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2014 American Transactions on Engineering & Applied Sciences.

American Transactions on Engineering & Applied Sciences http://TuEngr.com/ATEAS

International Editorial Board

Editor-in-Chief

Executive Editor

Associate Professor, South Dakota State University, USA

Associate Professor, Thammasat University, THAILAND

Zhong Hu, PhD

Boonsap Witchayangkoon, PhD

Associate Editors:

Associate Professor Dr. Ahmad Sanusi Hassan (Universiti Sains Malaysia ) Associate Prof. Dr.Vijay K. Goyal (University of Puerto Rico, Mayaguez) Associate Professor Dr. Narin Watanakul (Thammasat University, Thailand ) Assistant Research Professor Dr.Apichai Tuanyok (Northern Arizona University, USA) Associate Professor Dr. Kurt B. Wurm (New Mexico State University, USA ) Associate Prof. Dr. Jirarat Teeravaraprug (Thammasat University, Thailand) Dr. H. Mustafa Palancıoğlu (Erciyes University, Turkey )

Editorial Research Board Members

Professor Dr. Nellore S. Venkataraman (University of Puerto Rico, Mayaguez USA) Professor Dr. Marino Lupi (Università di Pisa, Italy) Professor Dr.Martin Tajmar (Dresden University of Technology, German ) Professor Dr. Gianni Caligiana (University of Bologna, Italy ) Professor Dr. Paolo Bassi ( Universita' di Bologna, Italy ) Associate Prof. Dr. Jale Tezcan (Southern Illinois University Carbondale, USA) Associate Prof. Dr. Burachat Chatveera (Thammasat University, Thailand) Associate Prof. Dr. Pietro Croce (University of Pisa, Italy) Associate Prof. Dr. Iraj H.P. Mamaghani (University of North Dakota, USA) Associate Prof. Dr. Wanchai Pijitrojana (Thammasat University, Thailand) Associate Prof. Dr. Nurak Grisadanurak (Thammasat University, Thailand ) Associate Prof.Dr. Montalee Sasananan (Thammasat University, Thailand ) Associate Prof. Dr. Gabriella Caroti (Università di Pisa, Italy) Associate Prof. Dr. Arti Ahluwalia (Università di Pisa, Italy) Assistant Prof. Dr. Malee Santikunaporn (Thammasat University, Thailand) Assistant Prof. Dr. Xi Lin (Boston University, USA ) Assistant Prof. Dr.Jie Cheng (University of Hawaii at Hilo, USA) Assistant Prof. Dr. Jeremiah Neubert (University of North Dakota, USA) Assistant Prof. Dr. Didem Ozevin (University of Illinois at Chicago, USA) Assistant Prof. Dr. Deepak Gupta (Southeast Missouri State University, USA) Assistant Prof. Dr. Xingmao (Samuel) Ma (Southern Illinois University Carbondale, USA) Assistant Prof. Dr. Aree Taylor (Thammasat University, Thailand) Assistant.Prof. Dr.Wuthichai Wongthatsanekorn (Thammasat University, Thailand ) Assistant Prof. Dr. Rasim Guldiken (University of South Florida, USA) Assistant Prof. Dr. Jaruek Teerawong (Khon Kaen University, Thailand) Assistant Prof. Dr. Luis A Montejo Valencia (University of Puerto Rico at Mayaguez) Assistant Prof. Dr. Ying Deng (University of South Dakota, USA) Assistant Prof. Dr. Apiwat Muttamara (Thammasat University, Thailand) Assistant Prof. Dr. Yang Deng (Montclair State University USA) Assistant Prof. Dr. Polacco Giovanni (Università di PISA, Italy) Dr. Monchai Pruekwilailert (Thammasat University, Thailand ) Dr. Piya Techateerawat (Thammasat University, Thailand ) Scientific and Technical Committee & Editorial Review Board on Engineering and Applied Sciences Dr. Yong Li (Research Associate, University of Missouri-Kansas City, USA) Dr. Ali H. Al-Jameel (University of Mosul, IRAQ) Dr. MENG GUO (Research Scientist, University of Michigan, Ann Arbor) Dr. Mohammad Hadi Dehghani Tafti (Tehran University of Medical Sciences)

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Contact & Office: Associate Professor Dr. Zhong Hu (E ditor-in-Chief), CEH 222, Box 2219 Mechanical Engineering Department, College of Engineering, Center for Accelerated Applications at the Nanoscale and PhotoActivated Nanostructured Systems, South Dakota Materials Evaluation and Testing Laboratory (METLab), South Dakota State University, Brookings, SD 57007 Tel: 1-(605) 688-4817 Fax: 1-(605) 688-5878 Zhong.Hu@sdstate.edu, Editor@TuEngr.com Postal Paid in USA.

2014 American Transactions on Engineering & Applied Sciences.

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Enhancement of Space Environment Via Healing Garden a

Ooi Say Jer and Fuziah Ibrahim a

a*

School of Housing, Building and Planning, Universiti Sains Malaysia, MALAYSIA

ARTICLEINFO

Article history: Received August 24, 2013 Received in revised form August 29, 2014 Accepted September 10, 2014 Available online September 15, 2014

Keywords: Garden element; Therapeutic landscape; Healing factors; Garden design.

ABSTRACT

Green nature, sunlight and fresh air have been known as important component of healing in healthcare facilities. This paper presents the finding of an exploratory study on healing garden elements in healthcare facilities. The purpose of the paper is to find the elements of healing gardens and its healing factors in the existing garden design. In conducting this research study, site observation and informal interview at selected healthcare facilities have been performed. The study reveals the elements of existing garden design, the interactivity and the end users expectation on a garden. The finding shows that lacking some of the elements of garden design lead to less user friendliness and interactivity in the garden.

It also shows that the visibility, accessibility, quietness and comfortable condition in the garden give impact to the utilization of the garden.

2014 Am. Trans. Eng. Appl. Sci.

1. Introduction The article highlights an exploratory study on the elements of garden and how they contribute to healing in general. The exploration would focus on two gardens with different design at two hospitals in Penang, Malaysia. The main methods of data collection were observation and informal interview with the patrons. The patrons were the patients and visitors at the garden. The study requires the exploration of the garden design and users’ experience, their expectation to the garden and how garden affect them. The study was a respond to Hartig and Marcus (2006) who emphasis *Corresponding author (Fuziah Ibrahim). Tel/Fax: +60-4-6532834. E-mail address: fuziah@usm.my.

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that garden is a combination of a place with process. Dilani (2001) also claims that the garden is to benefit all users either in general nor specific needs.

According to American Horticultural Therapy Association (2007), garden is a plant dominated environment with nature aspect such as plantations, flowers, waters and other aspects. It is a designed place for users to respite and relax. According to Marcus (2007), the meaning of the word “healing” in healing garden is not meant to “cure” and will not cure hard diseases or any physical damages but it can reduce stress to more balanced state, to build up self-confidence, to provide an environment for therapeutic program with patients and provide an alternative place for visitor from hospital interior.

The history and evolution of healing garden is being a long age and the significant of healing garden can be group into three by its goals and users (Sandel, 2004). The first group is vocational programs. It is design for skill and personal development and the goal is for work adaption and leadership modeling. The main purpose of the program is to help users recover from injures, sickness or disabilities and help users regain and involve into social activities. The main target of the program is employees. Sandel (2004) claimed that the second program is therapeutic program which collaborate with vocational program and is for self-development. The target of this program is more on a group, unlike vocational program which targeted on personal development. The therapeutic program showed effect and helped participants built their self-confident and social soft-skill through various method. The last program is social program which help maintaining personal physical and psychological recovery. The design of the garden under this concept only implements horticulture activities as recreational activity. Many garden designs in hospitals apply social program.

First systematic Post Occupancy Evaluation study on gardens in hospital are conducted in the San Francisco Bay Area in the United State in 1994 and the result shows that ninety percent of garden users experienced a positive change of mood after time spent outdoors (Marcus and Barnes, 1995).

According to Ulrich (1999), there is probably advantages and four potential advantages to healthcare facilities which is the reduction of stress in patients, staff and visitors, to reduced pain in patients, the reduction in depression, higher reported quality of life for chronic and terminally-ill 282

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and improved way-finding (especially if garden in prominent location). Besides, the potential advantages of healing garden to healthcare facilities is to reduced costs, the length of staying for certain patient categories will be shorter and fewer strong pain medication doses will be taken. The other potential advantages are to increased patient mobility and independence, and would increase patient and staff job satisfaction. Ulrich (1999) also claims that healing garden does not only give advantages to the patients, but also to the staff, who working in stressful jobs and difficult conditions. With staff hiring and retention an increasing problem in many Western countries, improving the work environment, includes providing outdoor space for breaks, can be an important investment.

2. Element of Healing Garden According to Marcus (2007), there are potential activities for users in garden which is viewing, sitting, walking, resting, meditation praying, receiving therapeutic program, reading, playing and sporting. Ulrich (1999) also states that there are four basic garden design guidelines with intent to use garden to reduce user’s stress in the Roger Ulrich’s Theory of Supportive Garden Design.

The first basic guideline would be to provide opportunities for movement and exercise.

Exercise is a combination of movement with physically and psychologically benefits, to improve cardio-vascular health and stress reduction among adults and children (Brannon and Feist, 1997; Koniak-Griffin, 1994). In this theory, setting with looped pathway system offer shorter and longer routes for user with few different functions. The first function is setting which facilitate physical therapist for outdoor therapeutic activity. The second function is setting which allow children running and playing and the third function is setting for contemplative walking (i.e., a maze) and for users to walk or jogging. The last function is setting with landscape for post-surgery exercise.

Ulrich (1999) claim that the second guideline should provide opportunities to make choices, seek privacy and experience a sense of control. Patient in hospital is experiencing limitation of freedom (Ulrich, 1999). Stress from limitation of freedom shows negative reaction on immune system functioning among patients and will decreased staff motivation. An interview with garden user shows that one of the major motivations for using garden is regaining freedom and reducing stress (Marcus and Barnes, 1995). As garden is to reduce user stress by sense of control, users *Corresponding author (Fuziah Ibrahim). Tel/Fax: +60-4-6532834. E-mail address: fuziah@usm.my.

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explore with the entire access able route and users must able to make decision by their own on which pathway they prefer, therefore, the design must offer different choices – place to be alone or with others; place to sit under sun or shade; place with broad or narrow view; fixed or moveable seating; different length of walking routes.

The third guideline claim by Ulrich (1999) is the garden design should encourage people gather together and experience social support. Research shows that higher level of social support will improve stress reduction and recovery rate for various medical conditions than isolated ones(Ulrich, 1999). The design is suggested to locate garden close to patient room, waiting area and main entrances in provide moveable seating, sub-space for small group to find privacy and to provide areas with tables and chairs for family and staff group to having meal together.

The last guideline is to encourage positive distractions with nature. According to Ulrich (1999), healing garden can have the effect to calm the mind, awakening the senses, stress reduction and can assist user to master their inner healing resources. To provide maximum therapeutic benefits, garden design must have multi ranging supply of plant material, i.e. with seasonal changes, subtleties of color, texture and shape. The design must also provide views to sky, trees can attract wildlife, and elements reflect sound of moving water.

Besides, there are another six requirement suggests by them to be consideration in garden design to reach garden’s full potential which is visibility, accessibility, familiarity, quiet, comfort and unambiguously positive art.

Under the visibility requirement, it stated that there are only three of over hundred acute care hospital included signage to outdoor garden or roof garden in their way-finding system. The design of outdoor space is recommended locating near building entrance or visible from main foyer so that users can access to garden easily without helps of signage.

The second requirement is accessibility. It stated that the garden must be used by all ages and abilities. The wide of pathway must be wide enough for two wheelchairs to pass horizontally (minimum of six feet) at the same time. The paving joints should be narrow enough so as not to harm to catch a cane, wheelchairs or IV-pole. Access to outdoor spaces are keep locked in many hospital to reduce use or maintenance. However, accessibility can be enhanced by have good visual access to garden from indoor.

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The third requirement claim by Ulrich et el.(1999) is familiarity. Many seek for familiar and comforting environment while in stressful condition. In medical setting, those who are sick or in anxiety may need to access to garden setting to relieve. They claims this is especially important in the hospices for terminally ill.

The forth is quietness. According to Marcus and Barnes (1995), a study of four hospital gardens found that users are disturbed by mechanical sound such as air conditioners and street traffic. Garden user need to feel calm and relax, and be able to feel the wind, the sound of the fountain, even sound of birds. Hence, the location of garden must be away from traffic, parking space and machinery room.

Comfort is one of the requirements. The garden design need to provide physiological comfort and psychologically secure for users - with choices of places to sit under sun or shade; seating which allowed sprawl or lie down; seats with arms and backs; paving material do not cause excessive glare; a special patio for smokers to separate from non-smoker users.

And the last requirement is unambiguously positive art. According to Niedenthal et al. (1994), people trend to project their stress onto nearby objects and people while anxiety and discomfort experienced inside have developed “emotional congruence” which mean the attention of a person will focus on those parts that match the viewer’s emotional state. Ulrich (1999) also state that the scene may be seen as interesting or discomfort experience by the non-stress person. Hence in place which may increase level of stress especially in hospital, the design elements must be unambiguously positive in their message. Complex sculpture design may be appropriate in museum or corporate setting but is not appropriate in hospital. A research shows that recovery rate of heart surgery patients which exposed to landscape photographs is higher and had lower anxiety and fewer doses of strong pain killer compare with other patients with no pictures (Ulrich, et al., 1999). Ulrich also state that a classic case of in appropriate sculpture design in one of the hospital in United State where abstract figures of birds in courtyard cause dislike and fear emotion by cancer patients in adjacent wards and is been removed.

*Corresponding author (Fuziah Ibrahim). Tel/Fax: +60-4-6532834. E-mail address: fuziah@usm.my.

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3. Methodology The methodology chosen for the preliminary study of garden was the observation method.

According to Guba and Lincoln(1994), observation methods can span paradigms in research, from structured observations to highly unstructured participant observation. They quoted that question of method should be secondary to questions of paradigm, which can guides the investigation, not only in choices of method but in ontologically and epistemologically fundamental ways.

Hammersley and Atkinson (2007) also claim that observation as a methodology clearly contributes to these understandings, as it can be employed in ‘natural’ settings, rather than those set up for research purposes such as interviews. And Walshe et.al (2001) claim that observation methods have advantages when the focus of research is on understanding actions, roles and behaviour. They claim that interview allowed patrons said what they did but an observation allowed researchers to see directly what patrons done.

Both hospitals were chosen for the preliminary study because they have specific therapeutic garden. Observations were made during the day. In the same time, a few of those who visited the gardens were informally interviewed in order to understand the reason they visited the space and their expectation of a garden.

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Result and Discussion

4.1 Observation at Hospital Seberang Jaya, Pulau Pinang Hospital Seberang Jaya is located at Seberang Perai Tengah district in Penang state. It started operating since October 1991 to serve people from Seberang Perai district especially people from Seberang Jaya area. Hospital Seberang Jaya is strategically located near to the North-South Expressway (PLUS) and the Butterworth-Kulim Expressway (BKE). The location is also near to the Prai Industrial Park, Bukit Mertajam City and Butterworth City. (Portal Rasmi Hospital Seberang Jaya, 2013). Figure 1 is a schematic plan shows the location of the hospital with its building arrangement.

Figure 2 (a) shows the main entrance and signage at main gate of the therapeutic garden. The main entrance is located in front of the hospital main road. The garden is visible and obviously seen by public. Figure 2 (b) shows the main route at the main entrance for the garden whereas Figure 2

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(c) and (d) shows the walkway in the garden. The route design is accessible for all ages and abilities. The pathway is accessible for wheelchair users as the width is about six feet. The paving joints in the garden are narrow enough so will not harm or catch a cane, wheelchairs or IV-pole.

Figure 1: The schematic plan of the healing garden in Hospital Seberang Jaya.

Figure 2: (a-b) The main entrance; (c-d) The walk way in the garden There are three pavilions in the garden. Figure 3 (a) and (b) shows the outlook of one of the pavilion. Figure 3 (c) and (d) shows the interior view in the pavilion. Figure 3 (c) shows that the route into the pavilion is designed accessible for wheelchair user and seat is provided in the *Corresponding author (Fuziah Ibrahim). Tel/Fax: +60-4-6532834. E-mail address: fuziah@usm.my.

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pavilion. Figure 3 (d) shows there is dustbin provided in the pavilion for user handling their disposal. Figure 3 (e) and (f) shows there are visitors resting inside the pavilion. The pavilion provided space for users to sit rest and to calm down.

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(e) (d) Figure 3: (a-b) pavilions in the garden; (c-d) interior view of pavilion; (e-d) activities in pavilion

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(b) (c) Figure 4: (a) Water fountain in the garden; (b-d) Facilities in the garden

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Figure 4 (a) shows the water fountain in the garden. The sound of water would give a calming effect on the people and would encourage positive distractions with the nature. Figure 4 (b) shows the reflexology facilities in the garden and Figure 4 (c) shows the physiotherapy facilities in the garden. The facilities would provide opportunities for movement and exercises. Figure 4 (d) shows that there is a little Surau provided beside the garden. The Surau would be convenient to Muslim users whose punctually in praying is important while they are in the garden.

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(a)

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Figure 5: (a) View beyond the garden; (b) Lacking of benches in the garden

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Figure 6: (a) View playground; (b) Sitting area in the playground; (c) Waiting area beside of the playground; (d) Public phone facilities near to the playground.

Figure 5 (a) shows that the garden is located near to the main road (please refer to schematic plan). The main road beyond the garden is North-South Expressway (PLUS) which would cause heavy traffic and noise. This might cause discomfort and disturbance to the users in fact might harm their health. Figure 5 (b) shows there are lack of benches in the garden; users might not have enough space to sit and rest when in the garden. The location of the therapeutic garden is strategically located for the hospital in the sense that it acts as a buffer zone from the noise of the heavy traffic to the hospital interiors.

There are playground facilities provided in the hospital and is located opposite the therapeutic the garden as shows in Figure 6 (a). Even thought it is not included as part of the garden but the researcher felt that it is relevant to the garden element as it provided opportunities for movement and exercises especially for children. At the same time, it also provides area for children to play when they felt bored waiting in the treatment rooms or the wards. Figure 6 (b) shows the sitting area in the playground for parents to sit and rest whiles their children playing at the playground.

Besides, waiting area is also provided beside of the playground as shown in Figure 6 (c) as alternative place to stay if sitting area in playground is full. Besides, since the playground is located *Corresponding author (Fuziah Ibrahim). Tel/Fax: +60-4-6532834. E-mail address: fuziah@usm.my.

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beside of the orthopedic clinic, patients prefer to be in the outside waiting area rather than staying in the clinic while waiting to receive treatment. Figure 6 (d) shows the public phone service is provided near to playground.

Figure 7: The schematic plan of the healing garden in Hospital Kepala Batas 3.1 Observation at Hospital Kepala Batas, Pulau Pinang The second observation site is the Hospital Kepala Batas, Pulau Pinang. Hospital Kepala Batas is located at Seberang Perai Utara district in Penang state and is operated since January 2003. It was built to give services to people in Seberang Perai Utara district and to served over two hundred and ninety thousand people from the district. In fact, Kepala Batas city is a new emerging develop district for Seberang Perai Utara. Kepala Batas is planned to move towards “Medical City� in the future and Hospital Kepala Batas plays an important role in the planning deveoplment. (Portal Rasmi Hospital Kepala Batas, 2013).

The design of the garden in the Hospital Kepala Batas is different with Hospital Seberang Jaya as it is designed with the courtyard within the hospital building as shows in Figure 8 (a). The garden fully utilize all spaces and is compacted in the courtyard (please refer to the schematic plan). Figure 8 (b), (c) and (d) shows the main entrance of the garden, the mixture of hard and soft landscape provides a pleasing and comfortable environment. Besides the main entrance it could be 290

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accessed from four other entrances. Tall trees which provided the needed shade are mixed well with herbal shrubs which enhances the space with colorful flowers, and sweet smelling Jasmine and other herbal flowers.

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Figure 8: (a) Location of the garden; (b-c) Main entrance of the garden; (d) Garden appearance

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Figure 9: (a-b) Water element in the garden; (c-d) Pathway design in the garden.

Figure 9 (a) and (b) shows two different designed water fountains in the garden. The sound of water would provide calming down and soothing effect to the users. Figure 9 (c) and (d) shows the pathway design in the garden. Although the pathway arrangements were too narrow and was not accessible for wheelchair users hence discouraging the wheelchair users, it was pleasant enough for other users to walk through the garden. The observation reveals that some patrons used the garden as a way to get to other parts of the building.

Figure 10 (a) shows the design of covered pathway in the garden. The covered pathway provided shading and users are not exposed to the sunlight and would stayed in the garden for longer period. Figure 10 (b) shows the sitting area in the garden. The sitting area is fully covered by the atap roofing material, hence users might free from exposure to sunlight and raining. Figure 10 (c) shows that people used the pathway in the garden as a short cut. The observation, shows that many people preferred to use the garden as a short cut to across to another place rather than using corridor. *Corresponding author (Fuziah Ibrahim). Tel/Fax: +60-4-6532834. E-mail address: fuziah@usm.my.

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(a)

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Figure 10: (a) Design of roof in the garden; (b) Sitting area in the garden; (c) User pass by the garden

(a) (b) Figure 11: (a-b) Pavilion in the garden.

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(e) (f) Figure 12: (a) Therapeutic garden in the hospital; (b) The function of the therapeutic garden; (c-f) The pathway design of the therapeutic garden.

There is only one pavilion in the garden as shows in Figure 11 (a) and (b). The small number of the pavilion would limit the amount of user. Figure 11 (a) and (b) shows that people used the pavilion for relaxing and having their meals. Interviewed conducted revealed that the pavilion is also used as a praying space by some Muslim patrons especially male Muslims.

Figure 12 (a) shows the label of the Therapeutic Garden. The garden is also used for 292

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reflexology as there is a reflexology pathway provided and shows in Figure (b). Figure 12 (c), (d), (e) and (f) shows the pathway design in the therapeutic garden with different tactile pathway. As the function is limited for reflexology, patient with leg injuries might be discouraged to use the garden.

(a) (b) Figure 13: (a-b) Route appearance at entrance Figure 13 (a) and (b) shows the route at the garden entrance. The step from the corridor to the garden is too high and might be dangerous to the users. The users need to alert while walking to the garden.

4. Summary of Discussion Table 1 shows the comparison of the finding of the elements of garden from Hospital Seberang Jaya and Hospital Kepala Batas with Roger Ulrich’s Theory of Supportive Garden Design (Ulrich, 1999). The overall design from each hospital met the requirement state in Roger Ulrich’s Theory.

In term of visibility, some user might not be aware there is a therapeutic garden in the Hospital Seberang Jaya as the location is located in front of hospital main door and is less strategic because most people are using side door to enter the hospital building. Comparatively, the location of the therapeutic garden in Hospital Kepala Batas is more visible due to its strategic location in the centre of the building. It is a nice calm retreat for all patrons, since it is located beside the pharmacy section. All out patients will go to the pharmacy to get their medications will not miss to see the garden and will eventually venture into it while waiting for their medications.

In term of accessibility, the therapeutic garden in Hospital Seberang Jaya could be accessible to all users, inclusive of wheelchair bound patients. The therapeutic garden in Hospital Kepala Batas is not accessible to wheelchair users because the paving of the pathway in the garden is too narrow for the wheelchairs. *Corresponding author (Fuziah Ibrahim). Tel/Fax: +60-4-6532834. E-mail address: fuziah@usm.my.

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Table 1: Comparison of the finding of the elements of garden from Hospital Seberang Jaya and Hospital Kepala Batas with Roger Ulrich’s Theory of Supportive Garden Design (Ulrich, 1999).

Element of Gardens from Roger Ulrich’s Theory of Hospital Seberang Hospital Kepala Supportive Garden Design (Ulrich 1999) Jaya Batas To provide opportunities for movement and exercise * * To provide opportunities to make choices, seek privacy * * To encourage people gather together and experience social support To encourage positive distractions with nature * * Visibility * Accessibility * Familiarity * * Quiet * Comfort * Unambiguously positive art * * Due to the location of the garden in Hospital Seberang Jaya, is quite noisy from the traffic of the North-South Expressway (PLUS), which is located in front of the hospital. In contrast, the patrons in Hospital Kepala Batas could really enjoyed the quietness of the garden since the location is in a form of courtyard in the hospital. The “noise” that the patrons could hear is the sound of the water fountain and sometimes the chipping sound of birds.

In term of comfort, patrons in Hospital Seberang Jaya would felt less comfortable compared with Hospital Kepala Batas due to less number of benches in the garden. The only sitting area in the garden is the three pavilions and patrons might not have enough sitting place when all the pavilions were fully occupied. However there are plenty of benches around the hospital compound itself.

Patrons in Hospital Kepala Batas would enjoyed more comfortable environment in the garden even though there is only one pavilion and one sitting area in the garden. The garden is located at the courtyard of the building and patrons might sit on the benches located at the corridor or in front of the pharmacy clinic.

Both the gardens do not actually have the element that would encourage people to gather together and experience social support. Both the gardens are meant for seclusion, resting and relaxing. Both the gardens also do have any unambiguously positive art. It is in accordance to Ulrich, et al(1999) as inappropriate sculptural abstract figures of birds in courtyard cause dislike and fear emotion by cancer patients in adjacent wards and had been removed in their respective hospitals.

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Beside the observation, informal interviews were conducted to identify level of the user’s satisfaction on the current garden condition.

Among the patrons, the major reason of them attending the hospital are for visiting family member or friends and others receiving treatment. Patrons went to the garden are to accompany their children to playground and waiting for relatives to receiving treatment. Some of them went to the garden for relaxation, having some quiet moments and even to do a bit of light stretching and excises.

On their satisfactory level to the current garden condition, for Hospital Seberang Jaya most of them are not satisfied due to the poor maintenance of playground and the cleanliness issues.

Patrons comment about not well maintained playground would be dangerous or even cause injury to the children. The grass in the garden is not well maintained and the cleanliness on the chairs and tables are not at acceptable level. There are areas in the garden that are quite hot in the afternoon that the patron refused to choose as substitute location to the clinic. However the garden in Hospital Kepala Batas is well maintained as approved by the patrons.

Since this study is conducted as a preliminary study to a prospective cohort study, the interviews were only conducted from the convenient samplings from the patrons who visited the garden. On the continuation of the study, further interview will be carried out to the staff of the healthcare facilities to reveal if they actually use the garden to calm down from their stressful work load. More healthcare facilities will be looked into especially those who claimed to have therapeutic gardens as well as healthcare facilities which do not have any therapeutic gardens.

5. Conclusion The study reveals that both the gardens met most of the requirement state by Roger Ulrich’s Theory of Supportive Garden Design, even though their design are different from each other. They have all the features of visibility, encouraging positive distraction with nature, easily accessible to most patrons, seeking some privacy from the crowded waiting areas in the hospital, some positive arts for relaxing the eyes.

The study reveals the patrons would chose to go to garden as their substitute location before or *Corresponding author (Fuziah Ibrahim). Tel/Fax: +60-4-6532834. E-mail address: fuziah@usm.my.

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while waiting for a treatment. The garden is a relief to the children who are getting easily bored while in hospital building. This exploratory study also shows that the playground for children and waiting space was the main demand among others and it should be taken as primary consideration in garden design. This finding suits to Ulrich (1999) as quoted in the Roger Ulrich’s Theory of Supportive Garden Design that the garden would provide opportunities for movement and exercise, to encourage positive distractions with nature and comfortable environment for users.

Garden with playground provided opportunities for movement and exercise, and comfortable environment lets users waiting their relatives in comfortable situation. The current condition in the garden is upgradable and the interactivity among users is expandable.

Hence, based on the findings in this preliminary study, playground and comfortable waiting space would be the added elements in the healing garden.

6. Acknowledgements The authors would like to thank reviewers who gave guidance and comment leading our article to higher efficient and quality.

7. References American Horticultural Therapy Association.(2007). Horticultural therapy[Online]. Retrieved Feb 15, 2008 from the World Wide Web: http://www.ahta.org/documents/Final_HT_Position_Paper_updated_409.pdf Bakas T. and Champion V. (1999). Development and psychometric testing of the Bakas caregiving outcomes scale. Nursing Research 48, 250–259.

Bowling A. (1997). Research Methods in Health. Open University Press, Buckingham.

Brannon, L. and J. Feist. (1997). Health Psychology, 3rd ed. Pacific Grove, CA: Brooks/Cole.

Catherine Walshe, Gail Ewing and Jane Griffiths. (2001). Using Observation as a Data Collection Method to Help Understand Patient and Professional Roles and Actions in Palliative Care Settings.

Chen M-L (1999) Validation of the structure of the perceived meanings of cancer pain inventory.

Journal of Advanced Nursing 30, 344–351.

Cooper Marcus, C. and M. Barnes. (1995). Gardens in Health Care Facilities: Uses, Therapeutic Benefits, and Design Considerations. Martinez, CA: The Center of Health Design.

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Cooper Marcus, C. and M. Barnes. (1999). Healing Gardens: Therapeutic Benefits and Design Recommendations, John Wiley and Sons, Ins. New York.

Cooper Marcus, C. (2007). Interdisciplinary Design and Research e-Journal. Volume I, Issue I: Design and Health.

Dilani, A. (Ed.). (2001). Design and Health: The Theraputic Benefits of Design. Svensk Byggtjånst, Stockholm.

Guba EG and Lincoln YS. (1994). Handbook of Qualitative Research. Thousand Oaks: Sage.

Hammersley M. and Atkinson P. Ethnography. (2007). Principles in Practice. 3rd ed. Routledge: London.

Hartig, T. & Marcus, C. C. (2006). Essay: Healing Gardens—Places for Nature in Health Care. The Lancet, 368, S36-S37.

Jeffreys MR. (2000). Development and psychometric evaluation of the transcultural self-efficacy tool: a synthesis of findings. Journal of Transcultural Nursing 11, 127–136.

Jones M.C. & Johnston DW. (1999). The derivation of a brief student nurse stress index. Work and Stress 13, 162–181.

Niedenthal, P. M., M. B. Setterland, and D. E. Jones (1994). “Emotional Organization of Perceptual Memory.” In P. M. Niedenthal and S. Kitayama (Eds.), The Heart’s Eye: Emotional Influences in Perception & Attention. San Diego: Academic Press, pp. 87-113.

Portal Rasmi Hospital Kepala Batas.(2013). Imbasan Sejarah[Online]. Retrieved July 20, 2013 from the World Wide Web: http://hkbatas.moh.gov.my/v2/modules/xt_conteudo/index.php?id=11 Portal Rasmi Hospital Seberang Jaya.(2013). Sejarah[Online]. Retrieved July 20, 2013 from the World Wide Web: http://hsbjy.moh.gov.my/v2/modules/xt_conteudo/index.php?id=10 Rattray J., Johnston M. and Wildsmith JAW. (2004). The intensive care experience: development of the intensive care experience (ICE) questionnaire. Journal of Advanced Nursing 47, 64– 73.

Rattray J and Jones M.C. (2005). Essential elements of questionnaire design and development.

Journal of Clinical Nursing 16, 234-243.

Sandel, M. H.(2004). Therapeutic Gardening in a Long-term Detention Setting. Journal for Juvenile Justice Service, 19(1&2), 123-131.

Sitzia J, Dikken C & Hughes J. (1997). Psychometric evaluation of a questionnaire to document side-effects of chemotherapy. Journal of Advanced Nursing 25, 999–1007.

Siu O-L. (2002). Predictors of job satisfaction and absenteeism in two samples of Hong Kong *Corresponding author (Fuziah Ibrahim). Tel/Fax: +60-4-6532834. E-mail address: fuziah@usm.my.

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Nurses. Journal of Advanced Nursing 40, 218–229.

Ulrich, R. S. (1999). Chapter 2, “Effects of Gardens on Health Outcomes: Theory and Research.”

In C.C. Marcus, and M. Barnes (Eds). Healing Gardens: Therapeutic Benefits and Design Recommendations. New York: John Wiley & Sons, pp. 27-86.

Waltz C & Jenkins L. (2001). Measurement of Nursing Outcomes: Volume 1: Measuring Nursing Performance in Practice, Education, and Research. Springer Publishing Company, New York.

Ooi Say Jer is a postgraduate student from School of Housing, Building and Planning in Universiti Sains Malaysia, Malaysia. He is pursuing his MSc. (Interior Design) program in research. His research work encompasses healing garden.

Dr. Fuziah Ibrahim is an Associate Professor in School of Housing, Building and Planning from Universiti Sains Malaysia, Malaysia. She is a lecturer in the Architectural Programme. Her Ph.D. is from Manchester Metropolitan University (1995), M.A. (Industrial Design) from Manchester Polytechnic (1991) and Hons. (HBP) from USM. She received a letter of commendation from the Head of Department for her research achievements carried out for her M.A. dissertation. Dr. Fuziah's specializes in product design and development and interior design.

Peer Review: This article has been internationally peer-reviewed and accepted for publication according to the guidelines given at the journal’s website.

Note: Original version of this article was accepted and presented at the International Workshop on Livable Cities (IWLC2013) – a joint conference with International Conference on Sustainable Architecture and Urban Design (ICSAUD2013) organized by the Centre of Research Initiatives and School of Housing, Building & Planning, Universiti Sains Malaysia, Penang, Malaysia from October 2rd to 5th, 2013.

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2014 American Transactions on Engineering & Applied Sciences.

American Transactions on Engineering & Applied Sciences http://TuEngr.com/ATEAS

Design of Quadruped Walking Robot with Spherical Shell Takeshi AOKI a b

a*

, Kazuki OGIHARA

b

Department of Advanced Robotics, Chiba Institute of Technology, JAPAN Future Robotics Technology Center, Chiba Institute of Technology, JAPAN

ARTICLEINFO

Article history: Received July 24, 2014 Accepted August 08, 2014 Available online August 12, 2014

Keywords: Mechanical design; Transformable robot; Disaster robot; Rescue engineering; Basic robot experiments.

ABSTRACT

We propose a new quadruped walking robot with a spherical shell, called "QRoSS." QRoSS is a transformable robot that can store its legs in the spherical shell. The shell not only absorbs external forces from all directions, but also improves mobile performance because of its round shape. In rescue operations at a disaster site, carrying robots into a site is dangerous for operators because doing so may result in a second accident. If QRoSS is used, instead of carrying robots in, they are thrown in, making the operation safe and easy. This paper reports details of the design concept and development of the prototype model.

Basic experiments were conducted to verify performance, which includes landing, rising and walking through a series of movements.

2014 Am. Trans. Eng. Appl. Sci.

1. Introduction Recently, many mobile robots have been developed to investigate and perform rescue operations at disaster sites where it is difficult for operators to enter. Two examples are the 510 Packbot (iRobot 510 PackBot, 2013), a commercial product, and Quince (Rohmer et al., 2013), both of which are in practical use. We believe that wide range searches using many small, inexpensive robots dedicated to search operations are effective in finding victims quickly. *Corresponding author (Takeshi AOKI). Tel/Fax: +81-47-478-0392. E-mail address: takeshi.aoki@it-chiba.ac.jp.

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However, carrying robots into a disaster site is dangerous; operators may be injured carrying them in, resulting in a second accident. Throwing the robots in over uneven terrain results in a safer, easier way of getting the robot into the site. Various search robots that can be thrown have been developed for military or security use. The packbot 110 FirstLook, made by iRobot, is a small type crawler vehicle with two flipper arms; it can climb over obstacles using its arms (iRobot 110 FirstLook, 2013). The SandFlea, made by Boston Dynamics, is a small wheel type vehicle comprising four wheels and a jump mechanism. It can move and jump over high steps using gas power (Boston Dynamics SandFlea, 2013). The Throwbot, made by Recon Robotics, comprises a column body and two wheels. It can be operated by wireless controller (Recon Robotics Throwbot, 2013). Each of these robots is small, very lightweight and resistant to shock.

Their wheels or crawler belt on the ends of their body and absorbs shock, so landing on a flat surface is fine. However, landing on uneven surfaces such as rubble in a disaster site causes shock to the robot body. We believe this robot needs shock absorbent materials that can withstand external force from all directions.

Walking robots can contact the ground over discrete points and the contact points can be arbitrarily selected according to terrain features. Recently, some robots have been field tested on uneven terrains with good results. The LittleDog (Buchli et al., 2009) and The BigDog (Boston Dynamics BigDog, 2013) are well-known quadruped walking robots made by Boston Dynamics; performance was tested by having them walk on easily collapsed rubble and on a mountain surface. The Titan X (Hodoshima et al, 2010) is a hybrid quadruped Walking Robot with the mobility of a crawler vehicle. Each leg mechanism has a crawler belt that can also be used as a drive train. The Titan X demonstrates proper performance over irregular ground using crawler mode and walking mode. Previous robots did not have a shock-proof function to protect the robot when it falls. Consequently, it was difficult for them to walk over irregular ground. Neither did they have the kinematic performance needed to recover from a fall.

We propose and aim to develop a new quadrupedal walking robot called "QroSS," which has a spherical outer shell and features walking mode and shock-proof mode. The mechanical design is reported here. The remainder of this paper is organized as follows: Section II overviews and discusses the design concept; Section III gives details of mechanical design; Section IV presents considerations on rising motions; and Section V presents and discusses basic experiments.

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2. Design Concept We assume the following rescue scenario for our robot, shown in Figure 1: a) getting investigation robot into disaster site from safe area by throwing, b) landing on rubble while absorbing shock, c) rising by extending its legs, and d) investigation by walking mode. QRoSS design requirements are that it must be shock absorbent, mobile and recoverable.

Figure 1: Application concept of our robot

Figure 2: Spherical shell for shock-proofing.

Figure 3: Omni-directional design for fall posture.

2.1 Basic Design Concept A spherical outer shell can receive external force from all directions, such as that shown in Figure 2. It is difficult for a rectangular solid shape to absorb landing shock completely on uneven surfaces. Many mobile robots have been proposed that have a ball outer shape and can roll through movement of a C.O.G. inside the outer shell. Traveling performance of these robots, *Corresponding author (Takeshi AOKI). Tel/Fax: +81-47-478-0392. E-mail address: takeshi.aoki@it-chiba.ac.jp.

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however, is low because reaction force of the rotating outer shell cannot be received with only the inside moment of the C.O.G. For that reason, we propose a quadruped walking robot with a spherical shell; it can change from ball mode to walking mode. With the common design of previous walking robots, because of the up and down directions, a rising mechanism is required when the robot lands upside down. directions.

We propose a new design concept that has no up and down

This is done by expanding the working range of each leg in the vertical direction

(Figure 3).

2.2 Design of Spherical Shell The transformable design from a ball shape to a walking mode is an old idea from ancient times. Two examples are “HARO,” a bipedal robot in Gundam, and “Destroyer droid,” a tripedal robot in Star Wars. These robots are unique mechanisms and achieving them has been difficult.

The MorpHex III is a transforming Hexapod Robot that can be changed to ball mode, hexapod walking mode and rotational transfer mode by leg actuators and a body actuator (Halvorsen, 2013). However, because the ball shape is formed by the leg mechanisms, it cannot withstand external force that impacts its spherical surface. Even if it uses a structure in which the outline of the leg mechanisms can receive force, designing it to be lightweight enough for a mobile robot is difficult.

Figure 4: Structure of spherical shell of QRoSS. We propose making the spherical outer shell and the walking mechanisms independent of each other. By doing so, our robot can achieve both functions: mobility of the legs and resistance to external shock. It can also be made small and lightweight. We designed the outer shell of the QRoSS with an outer spherical cage, rubber absorbers and a center pole with coil springs, shown in Figure 4. The cage is structured of wires featuring super elasticity. The center pole connects the outer cage through the absorbers, and the center frame, which is a base of legs, floats on the center pole over coil springs. With this structure, QRoSS can absorb external shock.

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2.3 Design of leg mechanism QRoSS’s legs must be mounted between the super elasticity wires of the spherical cage. The common joint arrangement of a quadruped walking robot, which is a spider type robot, is type A of Figure 5. However, the cage prevents work space of leg motion which swings along the horizontal plane. Therefore, because the legs must swing outside the cage, type B or type C of Figure 5 can be chosen. Because both types need a large work space for the knee joint – almost 360 degrees to achieve the omni-directional design in the vertical direction and storage legs in the shell – the knees must be double-jointed. However, type C cannot store the legs in the shell and the knee and the end part of the shin are outside, as shown in the upper figure of Figure 6. This is the case because type C cannot use the inside space of the shell effectively. Type B can move the shin part into the center area using the horizontal axis of the knee joint, shown in the lower figure of Figure 6. Thus, QRoSS uses the type B joints arrangement of the leg mechanisms.

Figure 5: Arrangement of joint axes.

Jumping robot (Kovac et al., 2009) has an outer cage and can jump on two legs; the cage can absorb external forces. This robot can roll over and return to its basic posture through the center of gravity effect, which is decentered. However, it cannot use outer its outer shell to travel; it uses only its legs. The QRoSS can use the outer shell as an extra contact point and to climb over high steps.

3. Mechanical Design of QRoSS Figure 7 is the first prototype model of the QRoSS and Table 1 lists specifications. The prototype model comprises the spherical outer shell and four legs; each leg is arranged radially from the center of the shell. Thus, the QRoSS does not have directivity in either the vertical direction or horizontal direction in preparation for landing on a complicated geographical surface. *Corresponding author (Takeshi AOKI). Tel/Fax: +81-47-478-0392. E-mail address: takeshi.aoki@it-chiba.ac.jp.

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Moreover, it can move using rotation of the spherical shell. This rotational torque is bigger than that of a rotational ball robot because the legs can receive the reaction force of the shell’s rotational torque. Each leg has three active DOFs: each actuator is a servo motor – a Futaba RS303MR with Maximum torque of 6.5[kgf-cm].

Battery is a Li-Fe battery (2 cells, 6.6[V],

300[mAh]); its running time approaches ten minutes.

Type C of joints arrangement: Leg structures overflows from the shell.

Type B of joints arrangement: The space in the shell can be used effectively.

Figure 6: Difference in storage states of joint arrangement of legs

Figure 7: First prototype model of QRoSS. 270

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Table 1: Specification of QRoSS. Height 247[mm] Width 240[mm] Diameter of spherical shell 210[mm] Mass (Including battery) 1039[g] DOFs 12 Actuators Futaba RS303MR Ground clearance 40[mm] Walking speed 140[mm/s]

Load is acted in front of a wire of the spherical outer shell

Load is acted in between wires of the spherical outer shell Figure 8: Structural analysis of spherical shell.

3.1 Spherical Outer Shell The outer shell is structured as a cage, which is 210[mm] diameter and comprises twelve wires, with a center pole through the absorbers.

The wires of the cage are super elasticity rods –

made of titanium alloys and a shape memory alloy. deformation does not reach the plastic region.

Therefore, when shocked from the outside,

At both ends of the super elastic rods, the amount

*Corresponding author (Takeshi AOKI). Tel/Fax: +81-47-478-0392. E-mail address: takeshi.aoki@it-chiba.ac.jp.

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of absorbable shock is small because deformations are restricted by connections to the hub.

To

absorb the shock in this part, the absorbers, which are made of a polyurethane foam, are arranged between the wire hub and the center pole.

Because an axial direction of the center pole has no

modification element (like an elastic rod) the center frame is floating, mounted on the pole by coil springs; it can slide on the surface and absorb the shock of an axial direction.

To select the wire diameter of the spherical shell, simulation of the structural analysis was performed using Autodesk Inventor.

In this simulation, a static load of 800[N] was applied to

the simulation model of the shell. This load is an equivalent value of an impact force: a robot's mass is set to 2[kg] and it is dropped from a height of 2[m] in free fall and an adsorption distance of 50 mm. From the analysis result, the wire diameter of the super elastic rod is set at φ2.3[mm], and 12 wires are used. This diameter is the largest size that can be purchased.

The upper figure

of Figure 8 illustrates receiving force from the front of a wire, and the following figure illustrates receiving force from a place where the interval of wires is the largest to expand leg mechanisms toward the exterior. Although deformation is too large when load is applied between wires, because the wire diameter is the maximum we can buy, we decided to make up for it by limiting the weight and distributing shock.

3.2 Leg Mechanism The leg mechanisms must be designed for an up-and-down symmetrical work space and stored in the outer shell. Taking into account modification of the cage of the spherical outer shell, the clearance between the leg and the cage is prevented when the rods are modified. We therefore decided to select a double joint mechanism. The upper picture of Figure 9 is the prototype model of the leg mechanisms. Each joint is called first, second and third joint from a base joint of the body (Figure 9). At the third joint, the activity and the passivity joints can be driven as same angles by combining two gears, which have the same number of teeth, to fold the legs completely.

Moreover, to be able to move the legs on the outside of the shell and prevent them from interfering with the wires of the cage when QRoSS is in walking mode, the second joint is arranged at the center of the leg to twist. Futaba RS303MRs are chosen as actuators of the leg joins; RS303MRs use serial communications and several servo motors can be operated through a single serial communication port of a micro controller. We designed the legs according to the specifications of this servo motor, in spite of its small output torque of only 6.5[kgfｼcm]. Small size and the ability to use serial communication were the most important reasons for selection.

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Each length of the leg mechanism is as follows: from the first joint to the passive joint of the third joint is 50[mm]; from the passivity joint to the activity of the third joint is 28[mm]; and from the activity joint to the end of the leg is 110[mm].

Figure 9: Prototype model of leg module.

Figure 10 shows the work ranges of the prototype is that leg mechanism. The work ranges in the vertical direction and the horizontal direction exceed 180 degrees, large enough to achieve operations.

To verify the work range of the leg in walking based on the CAD model of the

designed whole body, the range of the landing area of the end point of the leg, which changes with the height from the ground to the robot, was checked. Figure 11 shows the range on which the end point of the leg can land with the height of the robot. Results show that generations of walking motions are possible through planning the straight line paths required for walk operation in each circle.

Top view Side view Figure 10: Work range of leg module. *Corresponding author (Takeshi AOKI). Tel/Fax: +81-47-478-0392. E-mail address: takeshi.aoki@it-chiba.ac.jp.

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Figure 11: Results of paths of leg’s end point.

3.3 System Configuration Figure 12 shows the system configuration of the prototype model of QRoSS. We did only tele-operation because the purpose of this experimental model is to verify mobilities. QRoSS is controlled by one micro controller, the mbed NXP LPC1768 with a USB Bluetooth module.

These micro controllers produce the paths of the legs and command values for servo motors of the legs and communicate using RS485 serial communication protocol. Inclination of the body is always detected by the accelerometer and the deployment direction and rising direction of the legs are controlled. The prototype model is operated from a PlayStation 3 video game pad, using wireless LAN.

Figure 12: System configuration of prototype model.

4. Consideration of Rising Motion The rising motion of the QRoSS is achieved by the motion path of the legs. Because it 274

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cannot detect the contact point with the ground when it lands on rubble, it needs to rise by motion of the legs from every state. We should divide and take into account rising motion and standing motion, because the actuators of the legs have only small outputs. In considering the work ranges of the legs, the QRoSS needs to perform standing operation where contact points of the foot are near the outer shell. There is no directivity in the body of the QRoSS; however, the direction in which the legs are to be folded up is decided when the legs are stored. The state in which it cannot rise by one series motion exists depending on the body posture. The left figure of Figure 13 is a schematic illustration of the QRoSS in two-dimensional display; it is a rotational state.

Where φ is an attitude angle of the body, L0, L1, and L2 express each link of the leg, and θ1 and θ2 express the first joint and the third joint. When the grounding point of the spherical shell is the origin of x-y coordinates, the contact point of the leg is set to X and Y. If the tip of the foot has reached the ground, formulas (1) and (2) are materialized.

X = L0 cos ϕ + L1 cos(θ1 − ϕ ) + L2 cos(θ 2 − θ1 + ϕ )

(1)

Y = R − L0 sin ϕ + L1 sin(θ1 − ϕ ) + L2 sin(θ 2 − θ1 + ϕ )

(2)

Rotational state

Starting state

Figure 13: Two-dimensional model of QRoSS Although there are times when the tip of the foot may not reach the ground, the motion is not affected because the C.O.G. of the robot is at near center. If Y=0, the foot is on the ground, and x can be estimated, shown in the right figure of Figure 13. When x≥0, the QRoSS can rotate and rise in the CCW direction in a single motion. When x<0, however, by deploying the legs in the side direction of the shell, rotation is in the CW direction once, and rising occurs by slipping and closing the tip to the shell. Figure 14 is the result of estimating the border value of the rotating *Corresponding author (Takeshi AOKI). Tel/Fax: +81-47-478-0392. E-mail address: takeshi.aoki@it-chiba.ac.jp.

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direction; the horizontal axis is φ and the vertical axis is X. The parameters are as follows: L0=40[mm], L1=50[mm], L2 =120[mm] and θ1=90[deg] whose value can be fixed near the border state. The border value is 78.7[deg]. As the graph shows, the border line is 78.7[deg], the QRoSS can rise with a single motion at the left side of the line; at the right side, however, double motions are required. Because it needs the double motions to roll over in more than half the conditions, the double motion is adopted in the rising motion.

Figure 14: Rotational direction depending on attitude angle.

5. Experiments and Discussion Three performance experiments were conducted to verify effectiveness of our design concept. In this experiment, because the current of the servo motor could not be measured correctly, quantitative evaluation was not done. Because an external power cable and wire communication would prevent mobility of the experimental robot, the experiments were made using an internal battery and wireless controller. For those experiments, the motion paths – rising motion and crawl locomotion – were prepared as the basic motion paths.

The first experiment is verification of deployment of the leg mechanism from a spherical shape and the rising operation. In deployment operation, the legs are expanded after the accelerometer detects direction of the ground when all legs are stored (No.1 of Figure 15) from No.2 to No.3: all legs are expanded from the outer shell in the horizontal direction. The posture changes into a state in which it is easy to do rising operation with four legs from the state of fall posture by this operation. In rising operation, the posture can be changed and risen through paddling motion of the leg. To reduce overload torque at the third joint, the legs once put above the landing point of the tip of the feet, as in No.4, descend to the ground verticality, and the 276

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QRoSS finishes standing up, as in No.5. This results in confirming one series performance of rising operations.

Figure 15: Deployment legs and rising

Figure 16: Return from fall state by autonomous system. *Corresponding author (Takeshi AOKI). Tel/Fax: +81-47-478-0392. E-mail address: takeshi.aoki@it-chiba.ac.jp.

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Figure 17: One series operation of rescue mission The second experiment confirms rising operation of the autonomous system when the robot falls. Figure 16 is the result of the second experiment. Even when the posture of the QRoSS is in fall down and the reverse state, the accelerometer detected the situation, and the robot could rise by autonomous operation, confirming validity.

The third experiment confirms a series operation of the rescue missions. The following operations were performed as a series operation: throwing onto a flat surface, deployment of the legs, rising and walking, and turning by crawl locomotion. Figure 17 shows the result of the third experiment, a series of planning operations was demonstrated. In crawl locomotion of the walking mode, because the center of gravity is contained in the triangle consisting of landing points of supporting legs, stable walk is possible; maximum walking speed was 140[mm/s]. In this report, a prototype of the QRoSS was developed and validity of the design concept was confirmed. Because the return from the fall state becomes easy using a spherical outer shell, this 278

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robot can challenge travel on more difficult surfaces. However, because the first prototype model was small, large output torque of the actuators could not be analyzed and the length of the legs was restricted. Consequently, in this first prototype, locomotion has not been tested using the spherical shell. We believe that hybrid locomotion using the outer shell is an effective way of achieving mobility on uneven terrain. In future work, the second prototype model will be large enough to use actuators with sufficient output torque. And we want to demonstrate the robot at an actual disaster site and thereby prove validity.

6. Conclusion We proposed a quadruped walking robot (QRoSS) with a spherical shell and developed a first prototype model. QRoSS is a transformable robot and can change from the storage state in which four legs are stored in the spherical shell to deploy the legs outside the shell. The shell not only absorbs external forces from all directions, but also improves mobile performance by virtue of its round shape.

This paper discussed the QRoSS design concept, functional design,

structural design, and arrangement of the joints. Development of the first prototype model with the structural analysis of the cage was explained. Finally, we proved effectiveness of the prototype performance through basic experiments.

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Halvorsen. Morphex III. available from <http://www.robotee.com/index.php/ innovation-contest-winner-hexapod-morphex-31007/>, (accessed 2013-12-27).

M. Kovac, M. Schlegel, J.C. Zufferey and D. Floreano. (2009). A Miniature Jumping Robot with Self-Recovery Capabilities. Proc. of Int. Conf. on Intelligent Robots and Systems, 583-588.

Dr. Takeshi Aoki is an Associate Professor of Department of Advanced Robotics of Chiba Institute of Technology. He received his PhD in Engineering from Tokyo Institute of Technology in 2004 and was a researcher of the Tokyo Tech from 2004 to 2010. His current interests encompass mobile robots on uneven terrain, quadruped walking robots and rehabilitation tools.

Kazuki Ogihara is a Research Scientist of the Future Robotics Technology Center of Chiba Institute of Technology. He received the B. E. degree from Department of Advanced Robotics of the CIT in 2002. His current interests encompass rescue engineering, which is development of investigation robots in nuclear power plants, and a personal mobility.

Peer Review: The original of this article has been submitted to The 3rd International Conference on Design Engineering and Science (ICDES 2014), held at Pilsen, Czech Republic. The Paper Award Committee of ICDES 2014 has reviewed and selected this paper for journal publication.

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Takeshi AOKI and Kazuki OGIHARA

2014 American Transactions on Engineering & Applied Sciences.

American Transactions on Engineering & Applied Sciences http://TuEngr.com/ATEAS

Motion Analysis of Pitch Rotation Mechanism for Posture Control of Butterfly-style Flapping Robot Taro Fujikawa a b

a*

b

, Masahiro Shindo , and Koki Kikuchi

b

Department of Robotics and Mechatronics, Tokyo Denki University, JAPAN Department of Advanced Robotics, Chiba Institute of Technology, JAPAN

ARTICLEINFO

Article history: Received July 24, 2014 Accepted August 04, 2014 Available online August 08, 2014 Keywords: Flapping robot; Butterfly; Pitch rotation mechanism; Posture control; Pitch angle; Flapping angle.

A B S T RA C T

We developed a small flapping robot on the basis of movements made by a butterfly with a low flapping frequency of approximately 10 Hz, a few degrees of freedom of the wings, and a large flapping angle. In this study, we clarify the pitch rotation mechanism that is used to control its posture during takeoff for different initial pitch and flapping angles by the experiments of both manufactured robots and simulation models. The results indicate that the pitch angle can be controlled by altering the initial pitch angle at takeoff and the flapping angles. Furthermore, it is suggested that the initial pitch angle generates a proportional increase in the pitch angle during takeoff, and that certain flapping angles are conducive to increasing the tendency for pitch angle transition. Thus, it is shown that the direction of the flight led by periodic changing in the pitch angle can be controlled by optimizing control parameters such as initial pitch and flapping angles.

2014 Am. Trans. Eng. Appl. Sci.

1. Introduction Flying robots with various methods of lift and propulsion, such as unmanned air vehicles, airships, and multi-rotor helicopters, have been developed as observation systems because they are unaffected by ground conditions and have high versatility (Green 2006, Fukao 2003, and Holfman 2007). Although these robots exist in several sizes, smaller robots are effective for *Corresponding author (T.Fujikawa). Tel: +81-3-5284-5613 Fax: +81-3-5284-5698.

E-mail addresses: fujikawa@fr.dendai.ac.jp.

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passing through narrow spaces. Here, flying creatures whose wings have high flight capabilities such as ability to turn at right angles and to accelerate at more than 10 G from takeoff. The flapping mechanism of small flying insects is particularly useful for maneuvering through narrow spaces, such as gaps between debris. Although many insect-scale flapping robots have been developed thus far, they have not achieved practical flight (Deng 2006, Fearing 2000, Sitti 2001, and Wood 2008) because it is difficult to implement a heavy driving system such as a conventional actuator consisting of a motor, gears, and a battery in such a small body. In addition, the complexity of the link mechanism deteriorates the transmission efficiency because the viscosity factors such as friction are more dominant than inertia at this scale. To overcome such challenges, we developed a flapping robot modeled after a butterfly having a low flapping frequency of approximately 10 Hz and a few degrees of freedom (DOF) of the wings. This robot is equipped with a rubber motor as a lightweight actuator, which does not require converting electrical energy into mechanical energy. Furthermore, it contains a simple slider-crank mechanism with elastic links to enable a wide flapping angle. In our previous research (Udagawa 2007 and Fujikawa 2008, 2010), a manufactured flapping robot took off from an airspeed of 0 m/s and flew upward during the downstroke and then forward during the upstroke in a staircase pattern to mimic the flight trajectory of a butterfly. However, posture control was not realized.

Here, one of the characteristics of the butterfly-style flight is a posture control mechanism that raises the body pitch angle during the downstroke and lowers it during the upstroke, thereby synchronizing with flapping motion. Although, a butterfly has a few DOF of the wingsâ&#x20AC;&#x201D;control of its wings is complicatedâ&#x20AC;&#x201D;this insect flies skillfully.

Figure 1: Definitions of parameters used in motion analysis.

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Taro Fujikawa, Masahiro Shindo, and Koki Kikuchi

In this study, we analyze the periodical pitch rotation mechanism that affects the posture of a butterfly during the takeoff by using a manufactured flapping robot and numerical simulation.

Furthermore, we clarify the posture control mechanism to realize autonomous flight of the flapping robot.

Figure 2: Stroboscopic photographs of a butterfly captured during takeoff This paper is organized as follows: In section 2, we analyze the flight characteristics of a butterfly. In section 3, we describe the butterfly-style flapping robot and numerical simulation *Corresponding author (T.Fujikawa). Tel: +81-3-5284-5613 Fax: +81-3-5284-5698.

E-mail addresses: fujikawa@fr.dendai.ac.jp.

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model. In section 4, we analyze and discuss the pitch rotation mechanism of both robots and the simulation models. Finally, in section 5, we conclude the paper and outline future works.

2. Flight Characteristics of a Butterfly We analyzed the flight characteristics of a swallowtail butterfly (Papilio xuthus) during takeoff by using a 3-D high-speed camera system with a resolution of 640 × 480 pixels and 200 fps (Fujikawa, 2010). Figure 1 shows the definitions of parameters used in the motion analysis, and Figure 2 displays stroboscopic images of a butterfly captured during takeoff. The red line in Figure 2 denotes the trajectory of the center of the thorax.

Figure 3 shows a typical example of the relationship between flapping and pitch angles. As shown in the figure, the downstroke of the flapping begins at approximately 80 deg and the upstroke begins at approximately −60 deg; that is, a butterfly flaps its wings in asymmetric up-and-down motion. In addition, the pitch angle begins at approximately 20 deg and periodically changes with a phase difference of approximately 90 deg between the flapping and pitch angles. These results show that the asymmetric flapping angle and takeoff upon ascension affect the pitch rotation. It is thought that a butterfly controls its posture through effective management of these mechanisms.

Figure 3: Relationship between flapping and pitch angles during takeoff.

3. Butterfly-style flapping robot and numerical simulation model We manufactured a butterfly-style flapping robot and developed a numerical simulation model. The robot as shown in Figure 4, which was constructed in bamboo to be lightweight, is equipped with a rubber motor as an actuator for a high power–mass ratio. The wing membranes are thin films made of polyethylene. The slider-crank mechanism mounted on its rear translates the rotation of the actuator into the flapping motion of the wings. By bending the elastic links, a 254

Taro Fujikawa, Masahiro Shindo, and Koki Kikuchi

wide flapping angle such as that from 80 deg to (â&#x2C6;&#x2019;60) deg is obtained compared with using rigid links (Fujikawa, 2010).

Figure 5 shows the simulation model, the body of which consists of four mass points including the head, thorax 1, thorax 2, and abdomen, which are connected by springs and dampers. Both right and left wings are integrated with the respective fore and hind wings for synchronous movement. Each wing is divided in Nx-1 points along the wingspan direction and in Ny-1 points along chord direction, which are connected by springs and dampers. The finite element method (FEM) was used to calculate the body and wing motions and flow field around the wings; details have been previously documented (Fujikawa, 2008).

The manufactured robot was used in takeoff experiments to observe trajectories of the flight and transitions of its pitch angle. To analyze its lift, thrust, and pitch rotation moment around the center of mass, we used numerical simulation.

Wings

Elastic links

Slider-crank mechanism

Figure 4: Manufactured butterfly-style flapping robot

4. Motion analysis of pitch rotation mechanism 4.1 Parameters of flapping robots To analyze the flight characteristics for the pitch rotation mechanism, we manufactured three models. Model A has a flapping angle of 80 deg to â&#x2C6;&#x2019;60 deg, and an initial pitch angle of 15 deg based on the results of analysis of a butterfly. Model B has the same flapping angle as that of *Corresponding author (T.Fujikawa). Tel: +81-3-5284-5613 Fax: +81-3-5284-5698.

E-mail addresses: fujikawa@fr.dendai.ac.jp.

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Model A; however, its initial pitch angle is 0 deg. Model C has a flapping angle of 60 deg to â&#x2C6;&#x2019;80 deg and an initial pitch angle of 15 deg. The wing length and the chord length of each model are 53 mm and 42 mm, respectively, and the total mass of each model, including an actuator, is approximately 520 mg, which is equivalent to that of a butterfly.

Figure 5: Numerical simulation model We then performed experiments to clarify the following relationships for the takeoff motion by using a flapping frequency of 12 Hz for each model: (1)

For different initial pitch angles, a comparison experiment was conducted by using Model A and Model B.

(2)

For different flapping angles, a comparison experiment was conducted by using Model A and Model C.

Table 1 shows these experimental parameters.

Table 1: Parameters of flapping robots Model A Model B Flapping angle [deg] 80 ~ -60 80 ~ -60 Initial pitch angle [deg] 15 0 Flapping frequency [Hz] 12 12

Model C 60 ~ -80 15 12

4.2 Settings of Numerical Simulation Models The structural parameters of the numerical simulation models corresponded to those of manufactured flapping robot,

including a wing length of 53 mm, chord length of 42 mm, body

length of 38 mm (head 4 mm, thorax 10 mm, abdomen 24 mm), total mass of 520 mg (head 60 mg, thorax 150 mg, abdomen 210 mg, wing 100 mg), and wing thickness of a uniform 0.3 mm.

Taro Fujikawa, Masahiro Shindo, and Koki Kikuchi 256

Figure 6: Stroboscopic photographs of Model A captured during takeoff

Figure 7: Stroboscopic photographs of Model B captured during takeoff.

The computational scheme included the following parameters: wings were divided into Nx = 16 along the wingspan direction and Ny = 12 along the chord direction; node number of FEM *Corresponding author (T.Fujikawa). Tel: +81-3-5284-5613 Fax: +81-3-5284-5698.

E-mail addresses: fujikawa@fr.dendai.ac.jp.

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was approximately 700,000.

The computational space was set to be approximately 1,300 Ă&#x2014;

1,000 Ă&#x2014; 1,000 mm.

Figure 8: Transitions of pitch angles (left) and trajectories of center of mass (right) during takeoff of models A and B for manufactured flapping robot

Figure 9: Transitions of lift (left) and thrust (right) of models A and B by numerical simulation.

Figure 10: Transitions of pitch moment of models A and B by numerical simulation.

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Taro Fujikawa, Masahiro Shindo, and Koki Kikuchi

Figure 11: Stroboscopic photographs of model C captured during takeoff.

Figure 12: Transitions of pitch angle (left) and trajectories of center of mass (right) during takeoff of models A and C for manufactured flapping robot

4.3 Results and discussion 4.3.1

Different initial pitch angle

Figures 6 and 7 show stroboscopic photographs of takeoff of models A and B, respectively, which were captured by a high-speed camera. Figure 8 shows comparisons of transitions of pitch angle and trajectories of center mass. Figures 9 and 10 show comparisons of transitions of lift, thrust, and pitch rotation moment, respectively, of models A and B by numerical simulation. *Corresponding author (T.Fujikawa). Tel: +81-3-5284-5613 Fax: +81-3-5284-5698.

E-mail addresses: fujikawa@fr.dendai.ac.jp.

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The experiments revealed that the transition of pitch angle increased at a rate proportional to the initial pitch angle (Figure 8, left). An increase in initial pitch angle to Model A resulted in stronger backward flight during the downstroke than that observed in Model B (Figure 8, right).

The maximum lifts of models A and B were 0.028 N and 0.029 N, respectively, and maximum thrusts were 0.011 N and 0.012 N, respectively, for backward direction during the downstroke.

Because the pitch angle at the beginning of the upstroke of Model A (42 deg) became larger than that of Model B (29 deg), the lift of Model A (â&#x2C6;&#x2019;0.024 N) increased over that of Model B (â&#x2C6;&#x2019;0.021 N). That is, the flight level was lower in Model B (Figure 9, left), and the thrust of Model A at 0.025 N was larger than that of Model B at 0.023 N for foreword direction at a stroke cycle of approximately 0.75 (Figure 9, right). However, as shown Figure 10, the transitions of the pitch rotation moment showed little differences between the models because the angles of the downstrokes and upstrokes of both models were equal.

4.3.2

Different flapping angle

We performed the same experiments to compare different flapping angles during takeoff.

Figure 11 shows stroboscopic photographs captured during takeoff of Model C. Figure 12 shows comparisons of transitions of pitch angle and trajectories of center mass of manufactured hardware. Figures 13 and 14 show comparisons of transitions of lift, thrust, and pitch rotation moment of simulation models, respectively.

The transition of pitch angle of Model C showed an increasing tendency compared to that of Model A (Figure 12, left). Therefore, Model C showed stronger backward movement during the downstroke and more upward movement during the upstroke (Figure 12, right). Moreover, the lift during the downstroke of Model C reached a maximum faster than that of Model A, and its value at 0.031 N was larger than that of Model A. During the upstroke, distinctive characteristics of the transitions of lift were noted. The lift of Model C reached a maximum faster than that of Model A; however, although the lift of Model A was always negative, that of Model C remained positive until approximately 0.75 strokes (Figure 13, left). This result occurred because the pitch angle at the beginning of the upstroke was more than 60 deg, and the direction of the reaction force of the wings became downward. Therefore, the force of the flapping during the upstroke generated the lift. Here the maximum lift of Model C was 0.005 N. For thrust during the downstroke, because the pitch angle of Model C became larger than that of Model A, the thrust of Model C shifted to positive at an earlier point, which was observed as backward flight, than that 260

Taro Fujikawa, Masahiro Shindo, and Koki Kikuchi

of Model A (Figure 13, right). During upstroke, because the pitch angle of Model C reached nearly 90 deg, its thrust was larger than that of Model A. The maximum thrusts of Model C during downstroke and upstroke were 0.007 N and 0.030 N, respectively. As shown in Figure 14, because the total pitch rotation moment of Model C was larger than that of Model A, its nose-up movement was also larger than that of Model A. Hence, the pitch angle of Model C was increased over that of Model A. However, if the pitch angle at the start of the second stroke becomes over 45 deg, reaction force of the wings during downstroke generates backward thrust and then hardware does a backflip. Therefore, it is necessary to control the body pitch angle over 45 deg at the end of downstroke and under 45 deg at the end of upstroke like a Model A in the case of level flight.

Figure 13: Transitions of lift (left) and thrust (right) of models A and C by numerical simulation.

Figure 14: Transitions of pitch moment of models A and C by numerical simulation.

5. Conclusion To realize posture control of a butterfly-style flapping robot, we analyzed the pitch rotation mechanism that occurs during takeoff by performing experiments of hardware and numerical *Corresponding author (T.Fujikawa). Tel: +81-3-5284-5613 Fax: +81-3-5284-5698.

E-mail addresses: fujikawa@fr.dendai.ac.jp.

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simulation for different initial pitch angles and flapping angles. We demonstrated that the pitch angle is controlled by the initial flapping angle at takeoff for increasing the angle and by different flapping angles to generate the increasing tendency in the transition of the pitch angle. Thus, it was shown that these parameters control the direction of flight.

In future research, we aim to investigate the mechanism for yaw and roll control to realize autonomous flight of a butterfly-style flapping robot.

6. Acknowledgements This research was partially supported by Research Institute for Science and Technology of Tokyo Denki University Grant Number Q13T-06/Japan. The authors would like to express their deep gratitude to all involved in the research project.

7. References E. W. Green and P. Y. Oh. (2006). Autonomous Hovering of a Fixed-Wing Micro Air Vehicle. Proceedings of 2006 IEEE International Conference on Robotics and Automation. 2164-2169.

G. Hoffman, H. Huang, et al.. (2007). Quadrotor Helicopter Flight Dynamics and Control: Theory and Experiment. Proceedings of 2007 International Conference on the American Institute of Aeronautics and Astronautics. 1-20.

M. Sitti. (2001). PZT Actuated Four-Bar Mechanism with Two Flexible Links for Micromechanical Flying Insect Thorax. proceedings of IEEE International Conference on Robotics and Automation. 3893-3900.

R. J. Wood. (2007). Design, fabrication, and analysis of a 3 DOF, 3cm flapping-wing MAV. proceedings of IEEE International Conference on Intelligent Robots and Systems.

1576-1581.

R. J. Wood. (2008). The First Takeoff of a Biologically Inspired At-Scale Robotic Insect.

IEEE Trans. Rob. 24(2). 341-347.

R. S. Fearing, K. H. Chiang, M. H. Dickinson, D. L. Pick, M. Sitti, and J. Yan. (2000). Wing Transmission for a Micromechanical Flying Insect. proceedings of IEEE International Conference on Robotics and Automation. 1509-1516.

T. Fujikawa, et al.. (2008). Development of a Small Flapping Robot -Motion Analysis during Takeoff by Numerical Simulation and Experiment-. Mechanical Systems and Signal Processing (MSSP). 22(6). 1304-1315.

T. Fujikawa, Y. Sato, T. Yamashita, and K. Kikuchi. (2010). Development of A Lead-Lag Mechanism Using Simple Flexible Links for A Small Butterfly-Style Flapping Robot.

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ISIAC2010.

T. Fukao, K. Fujitani, T. Kanade. (2003). An autonomous blimp for a surveillance system.

Proceedings of 2003 IEEE/RSJ International Conference on Intelligent Robots and Systems. 1829-1825.

T. Udagawa, T. Fujikawa, X. GAO, and K. Kikuchi. (2005). Development of a Small-Sized Flapping Robot. JSDE The 1st International Conference on Design Engineering and Science. 283-288.

X. Deng, L. Schenato, W. Chung Wu, and S. S. Sastry. (2006). Flapping Flight for Biomimetic Robotic Insects: Part I â&#x20AC;&#x201C; System Modeling. IEEE Trans. Rob.. 22(4).

776-788.

Dr. Taro Fujikawa is an Assistant Professor of Department of Robotics and Mechatronics at Tokyo Denki University, Japan. He received his Ph.D. in Engineering from Chiba Institute of Technology, Japan, in 2011. From 2011 to 2012, he was a Postdoctoral Researcher at Research Institute of Chiba Institute of Technology. He was a recipient of the Miura Award, the Japan Society of Mechanical Engineers in 2007, and the Best Paper Award of the 1st International Conference of Design Engineering and Science (ICDES2005). His research interests include biomimetic robots, mobility vehicles, and mechanical engineering design.

Masahiro Shindo is a graduate student of Department of Advanced Robotics, Chiba Institute of Technology, Japan. He received his degree in Engineering from Chiba Institute of Technology in 2013. He also received the Hatakeyama Award, the Japan Society of Mechanical Engineers in 2013. He investigates the flight mechanism of a butterfly using a three-dimensional computational fluid analysis and an insect-scale flapping robot.

Dr.Koki Kikuchi is a professor of Department of Advanced Robotics, Chiba Institute of Technology, Japan. He received his Ph.D. in Engineering from Tokyo University of Science in 1999. He also received the best paper award of the International Conference of Design Engineering and Science (ICDES2005) from Japan Society of Design Engineering, JSDE, and the best paper award of journal of JSDE. He investigates mechanisms creating insect abilities and develops small robots such as a butterfly-style flapping robot, vertical wall climbing robot, on-water running robot, etc. based on insect scale physics.

Peer Review: The original of this article has been submitted to The 3rd International Conference on Design Engineering and Science (ICDES 2014), held at Pilsen, Czech Republic. The Paper Award Committee of ICDES 2014 has reviewed and selected this paper for journal publication.

*Corresponding author (T.Fujikawa). Tel: +81-3-5284-5613 Fax: +81-3-5284-5698.

E-mail addresses: fujikawa@fr.dendai.ac.jp.

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2014 American Transactions on Engineering & Applied Sciences.

American Transactions on Engineering & Applied Sciences http://TuEngr.com/ATEAS

Analysis of Roll Rotation Mechanism of a Butterfly for Development of a Small Flapping Robot Masahiro SHINDO a b

a*

b

, Taro FUJIKAWA , Koki KIKUCHI

a

Department of Advanced Robotics, Chiba Institute of Technology, JAPAN Department of Robotics and Mechatronics, Tokyo Denki University, JAPAN

ARTICLEINFO

Article history: Received July 24, 2014 Accepted July 31, 2014 Available online August 01, 2014

A B S T RA C T

In this paper, we investigated the aerodynamic characteristics during roll rotation of a butterfly based on computational fluid dynamics using a three-dimensional high-speed camera information. This method allows to create a numerical model of a butterfly from the camera images and to analyze the flow field corresponding to the captured behavior.

Keywords: We photographed two behaviors different in rotational axis and analyzed CFD; the roll rotational mechanism. In a typical pitch rotational flight, the Flapping flight; differential pressure was concentrated on the tip of fore wings. The Roll rotation; magnitudes of reaction forces on left and right wings were roughly Posture control; Aerodynamic characteristics. matched each other. On the other hands, the differential pressure of the roll rotational flight was distributed in the whole of wings. The magnitude of the right reaction force was twice greater than that of left at the first down stroke. The roll angle changed largely at the same time.

These results show that a butterfly rotates about roll by changing the reaction forces on each side.

2014 Am. Trans. Eng. Appl. Sci.

1. Introduction Birds and insects flap to achieve flight and can perform wonderful aerial feats such as vertical takeoff and landing, snap turns, and hovering.

They gain high maneuverability by

utilizing the vortices around the wings. A butterfly is a suitable model on which to base *Corresponding author (Masahiro Shindo). Email address: s1376014we@s.chibakoudai.jp.

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autonomous micro aerial vehicles (MAV), due to its sub-gram weight, low flapping frequency and a few degrees of freedom compared to other flying insects.

To develop a small flapping

robot, many studies on the flight mechanism of butterflies have been carried out (Wood 2011, 2013 and Shen 2012).

Takahashi et al. have developed a micro strain sensor using micro

electronic mechanical systems (MEMS) and measured the pressure by mounting it on the wings (Takahashi, 2012).

The result of measurement showed that the differential pressure on the fore

wings was dominant over the pressure on the hind wings. However, in this experiment, the butterfly flew while pulling a signal wire because the sensor was physically connected to an external circuit board.

Therefore, it is possible that the flight behavior was different to that of an

untethered butterfly.

Fuchiwaki et al. have visualized vortices around two kinds of butterfly

using particle image velocimetry (PIV) (Fuchiwaki, 2013).

The results show that a vortex ring

is formed at the beginning of the down stroke and passes over the body with growing vortices and flow speed regardless of the type of a butterfly.

The PIV method is able to analyze the air

flow in an arbitrary plane in space; however, flapping is a complex 3D action which requires the 3D visualization of vortices.

We clarify the attitude recovering mechanism of a butterfly by analyzing an untethered butterfly and visualizing the pressure and vortices. We photograph the flapping behavior using a 3D high speed camera system.

The 3D data from different points on the butterfly wings are

obtained from all three directions. The attitude (roll, pitch, and yaw angles) and flapping angle are determined by using these points. These points and velocities are also used as the boundary conditions for computational fluid dynamics (CFD). By reproducing the actual behavior of a butterfly in a computer, the airflow around the measured points can be deduced.

Based on this

numerical procedure, the magnitude and distribution of pressure and the behavior of the vortices can be visualized. Accordingly, the lift and drag forces on the butterfly are calculated by considering the pressure over the whole wing.

This study clarifies the roll rotation mechanism

of a butterfly by determining the reaction force exerted and the angular moments during flight.

2. Photography of Flight Behavior 2.1 Analysis of the Images In this study, we photographed the free flight behavior of Papilio xuthus using a 3D high speed camera system (Figure 1). The camera coordinate system has three axes parallel to the 234

Masahiro Shindo, Taro Fujikawa, and Koki Kikuchi

camera directions and its origin is fixed at the takeoff point of the butterfly.

All cameras are

orthogonally located 1,500mm from the roost. Table 1 shows the photography parameters.

The captured space is 250 × 250 × 250 mm3.

The positions of the cameras are identified by

calibration using a target, and then the coordinates of the measured points are calculated using epipolar geometry.

Figure 1: Camera configuration.

Table 1: Camera parameter.

Frame rate 1000 frame/sec Image resolution 1280 × 1024 pixels Shutter speed 1/5000 sec

L4

B1

L3 L2

L

R2 L

Fore wing

R3

L6

B2

R4 R5

R1 R

B3

Interest points Hind wing

L

R7 L8

L9

B4

R9

R8

Figure 2: Interest points of body and wing. *Corresponding author (Masahiro Shindo). Email address: s1376014we@s.chibakoudai.jp.

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Figure 2 shows the measured points of the butterfly. The body is divided into three parts: head, thorax, and abdomen (B1-B4 in Figure 2).

The measurements of the wings are carried out

along the edges since the opaque wings occlude points on the surfaces frequently during flight (L1-L9 and R1-R9 in Figure 2).

2.2 Definitions of the Parameters To determine the attitude and flight parameters of a butterfly, we define the butterfly coordinate system Σ B (Figure 3).

The XB axis is the vector from B1 to B3. The ZB axis is the

vector product of the XB axis and the body-span vector from L1 to R1. The YB axis is the vector product of ZB and XB.

Figure 3: Definitions of the butterfly frame, angles, and posture.

The attitude of the butterfly is shown in Figure 3, in which the roll, pitch, and yaw angles are denoted by φ , θ , and ψ , respectively. Here, we define horizontal and vertical body planes that have ZB and XB as normal vectors. The roll, pitch, and yaw angles are defined as follows: 236

Masahiro Shindo, Taro Fujikawa, and Koki Kikuchi

φ is the angle between the horizontal body plane and the Y axis, θ is the angle between the horizontal body plane and the X axis, and ψ is the angle between the vertical body plane and the Y axis.

The flight parameters describing the state of the butterfly are chosen as follows:

The angle

between the horizontal body plane and the normal vector of the fore wing is defined as the flapping angle.

The flapping cycle is divided into two phases, up and down strokes.

defined the lead-lag angle as a parameter which describes the wing state.

We also

The lead-lag motion

of a butterfly controls not only the pressure center on the wings but also the wing area by overlapping the fore and hind wings (Fujikawa, 2008, 2010 and Udagawa, 2005).

This motion

is parameterized by the angle between the vertical body plane and the vector from the root to the tip of the wing.

The parameter describing the state of the abdomen is as follows:

swings its abdomen horizontally and vertically as well as flapping.

A butterfly

The vertical abdomen angle

is defined as the angle between the horizontal body plane and the abdomen vector from B3 to B4.

The horizontal abdomen angle is the angle between the body and the abdomen vectors.

3. Computational Fluid Dynamics 3.1 Boundary Conditions around a Butterfly In this study, we analyzed the flow field around a real butterfly flying in the photographed space. Using the measured points and velocities defined in the previous section as the mesh boundaries, the behavior of real vortices can be visualized. The wing and body are divided into meshes bounded by the measured points (Figure 4).

The leading edges of the fore wings (L1-L5

and R1-R5) and the side edges of the hind wings (L6-L8 and R6-R8) are approximated to match a butterfly wing shape using third order spline interpolation.

The body and other wing sections

are divided linearly. To simplify the calculation, our simulation considers the fore and hind wings as one. The body of the butterfly model is composed of three parts, head, thorax, and abdomen.

These parts are cylindrical and their axes are the lines which join the measured points.

The coordinates of the butterfly are obtained by image processing every millisecond using a 1000 frame per second camera.

To improve calculation accuracy, we further divided these data

intervals into 0.01ms periods through the natural third spline interpolation. The approximate curve is continuous up to second order. *Corresponding author (Masahiro Shindo). Email address: s1376014we@s.chibakoudai.jp.

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3.2 Governing Equations of the Flow The numerical solver in this study analyzes the air flow caused by the flapping motion of the butterfly using the measured points and velocities as the boundary conditions.

The governing

equations for CFD are the continuity equation and the Navier-Stokes equation. The flow is considered to be 3D, incompressible, and unsteady.

In equation (1), U, ρ , P, and µ are the

mean velocity vector of flow, density, pressure, and the coefficient of viscosity, respectively.

∇⋅ U = 0  ∂U µ 1  + (U ⋅ ∇ )U = − ∇P + ∇ 2 U  ∂ t ρ ρ

(1)

Finite element method (FEM) was used for the calculation scheme. and maintains high accuracy with large mesh deformation.

This method is stable

The calculation space mesh tends to

deform because the flapping range of a butterfly is far wider than that of other insects, at almost

4

40

36

4

Node

6

Cell

Interest point Figure 4: Meshing for CFD: division numbers of the body and wing.

180deg.

Therefore, we adopt an arbitrary Lagrangian-Eulerian (ALE) method for the

deformation and motion of the calculation space and butterfly meshes.

The calculation of flow

is stabilized using the stream-upwind/Petrov-Galerkin (SUPG) method.

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Masahiro Shindo, Taro Fujikawa, and Koki Kikuchi

Dividing the

Navier-Stokes equation into two terms using a simplified marker and cell method (SMAC) method allows the explicit and implicit calculations of velocity and pressure, respectively.

The size of the calculation space is 130 × 100 × 100cm3 and the number of nodes for FEM is 94 × 108 × 75.

Figure 5 shows the boundary conditions of the space.

ucal, vcal, and wcal denote the velocities of the butterfly and the wall.

Here, ubody, vbody, wbody,

The origin of the coordinate

system of the calculation space is fixed at the initial position of the thorax and the X axis points in the opposite direction to the butterfly’s movement.

Z Y X

Figure 5: Calculation space and boundary conditions.

4. Computational Fluid Dynamics We photographed two kinds of flight patterns in which the butterfly rotated around different axes, to clarify the butterfly’s rotation mechanisms. Section 4.1 describes a pitch rotation which is a typical flight pattern for a butterfly. Section 4.2 describes a roll rotation and clarifies the attitude recovering mechanism for rotating from a rolled state to a horizontal state.

4.1 Flow Field of a Pitch Rotational Flight In this section, we describe the typical pitch rotational flight pattern. The initial attitude of the butterfly was φ = 1.5 deg, φ = 23.4 deg, and φ = −2.8 deg. of the flapping, pitch, and roll angles.

Figure 6 shows the transitions

It can be seen that the pitch angle increased

simultaneously with the down stroke. The wing motion changed from the down stroke to the up *Corresponding author (Masahiro Shindo). Email address: s1376014we@s.chibakoudai.jp.

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stroke at a flapping angle of â&#x2C6;&#x2019; 70 deg.

The pitch angle continued to increase for 10ms after the

stroke reversal. The reaction force on the wing provided the thrust since the stroke was in the positive X direction. decreasing pitch angle.

In the up stroke phase from 31ms to 81ms, the butterfly flew forward with The down stroke started again at a flapping angle of 80deg.

the first stroke, the pitch angle increased with a delay of 10ms in the second stroke. angle was almost unchanged throughout the two flapping cycles.

As well as The roll

The maximal variation was

25deg at a flapping angle of â&#x2C6;&#x2019; 10 deg during a first upstroke (Figure 6).

Figure 6: Time history of the angles: Pitch rotational flight.

Figure 7 shows the streamlines around the wings caused by the flapping motion.

The

streamlines are colored according to the flow speed, where the red lines are faster and blue lines are slower. The leading-edge vortices (LEV) and wing tip vortices (WTV) which were present on the upper surface of the wing were generated during the down stroke.

These vortices

decrease pressure causing the differential pressure between the top and bottom surfaces of the wing.

Dickinson et al. have reported the lift generation mechanisms (Dickinson, 1999), which

are as follows. Rotational circulation means that the rotation of the wing at the time of the stroke reversal generates an upward force.

The wake capture mechanism explains the increase

in aerodynamic force during the stroke reversal. right wings during two flapping cycles.

Figure 8 shows the twist angle of the left and

It shows that the twist angle changed at the time of the

stroke reversal. We think that the lift force was increased by rotational circulation at that time (Dickinson, 1999). The axes of the vortices are parallel to the wing surface.

Masahiro Shindo, Taro Fujikawa, and Koki Kikuchi 240

Figure 9 shows the constant pressure surfaces on the wings as stroboscopic images.

The

red and blue surfaces show positive and negative pressures of 0.8Pa and â&#x2C6;&#x2019; 0.8 Pa, respectively.

The pressure is positive on the upper side and negative underneath during the down stroke.

0 ms

5 ms

12 ms

17 ms

28 ms

41 ms

51 ms

58 ms

70 ms

The

Figure 7: Stroboscopic images of streamlines: Pitch rotational flight. *Corresponding author (Masahiro Shindo). Email address: s1376014we@s.chibakoudai.jp.

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butterfly rose with increasing pitch angle due to the differential pressure that concentrated near the leading-edge of the fore wings. The pressure is positive underneath the wings and negative

Figure 8: Time history of twist angles: Pitch rotational flight. on the upper side during the up stroke. Similarly to the down stroke, the butterfly flew forward with decreasing pitch angle due to the differential pressure that concentrated near the leading-edge of the fore wings.

Figure 10 shows the time history of the reaction force on the left and right wings.

During

the pitch rotational flight pattern, the reaction forces of the left and right wings were changed in the similar tendency.

The force on the right wing exceeded that on the left wing during the first

down stroke. This continued until the upstroke at 46ms, at which time the roll angle also increased. From the start of the second flapping cycle, the reaction forces on the left and right wings were the same and the roll angle of the butterfly did not change.

4.2 Flow Field of a Roll Rotational Flight This section describes the mechanism for rotating from a rolled state to a horizontal state. The initial attitude of the butterfly was φ = −58.0 deg, θ = 52.1 deg, and ψ = −87.8 deg. shows the transition of the flapping, pitch, and roll angles.

Figure 11

Unlike the previous flight pattern,

the maximum variation in pitch angle was 25deg. The pitch angle decreased with the down stroke because the butterfly took off from the bottom side of the roost.

The roll angle also

decreased and the butterfly rotated around the roll axis in the clockwise direction.

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0 ms

5 ms

12 ms

17 ms

28 ms

41 ms

51 ms

58 ms

70 ms

Figure 9: Stroboscopic images of the constant pressure surfaces: Pitch rotational flight.

*Corresponding author (Masahiro Shindo). Email address: s1376014we@s.chibakoudai.jp.

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Figure 10: Time history of the reaction forces: Pitch rotational flight.

The reaction force acted in the negative X direction since the pitch angle was 50deg.

The

butterfly moved 5mm in the Z direction. The down stroke ended and the upstroke began at a flapping angle of -50deg. The pitch angle decreased for 10ms at the beginning of the upstroke.

After that, it continued to increase until reaching a maximum at a flapping angle of 75deg.

On

the second down stroke, the flapping motion of the right wing preceded that of the left wing by 5ms.

From this point the roll angle started to change.

From 65ms, the rotational moment

around the roll axis increased over 5ms because the direction of the reaction forces on the right and left wings were different.

Figure 12 shows the streamlines around the wing.

The LEVs and WTVs, which were

present on the upper surface of the wing, were generated during the down stroke, as in the pitch rotation maneuver.

Figure 13 shows that the twist angle decreased from the beginning of down

stroke and this angle also increased 10ms before the stroke reversal.

We conclude that the

butterfly, similarly to Drosophila, used rotational circulation by advancing the fore wing to the

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Figure 11: Time history of the angles: Pitch rotational flight. hind wing (Dickinson, 1999; Lehmannl, 2005).

The behavior of the vortices during the

upstroke was different to that in the pitch rotation maneuver.

In this case, the axis of the WTVs

intersected the wings.

Figure 14 shows the constant pressure surfaces at the same time as those shown in Figure 12.

The pressure distribution during the down stroke was similar to that in the pitch rotational flight pattern; however, that in the up stroke was different.

The differential pressure during the up

stroke concentrated near the leading-edges of the fore wings during the pitch rotation. roll rotation, however, it extended across the whole wing.

The variation in pitch rotation was

slight because the magnitudes of the reaction forces on the wings were equal. the time history of the reaction force on the wings.

In the

Figure 15 shows

The reaction force on the right wing

preceded that on left wing by 5ms when the second down stroke started.

The butterfly rotated

around the roll axis due to the angular moment generated. During the second down stroke, the maximal force on the right wing was 400mN, while that on the left wing was 220mN.

The

reaction force on the left wing was also larger than that on the right wing during the second up stroke. The roll attitude of the butterfly, which was initially roll-rotated at â&#x2C6;&#x2019; 58.0 deg, became approximately horizontal at the start of the third down stroke. *Corresponding author (Masahiro Shindo). Email address: s1376014we@s.chibakoudai.jp.

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0 ms

5 ms

13 ms

21 ms

27 ms

37 ms

44 ms

52 ms

58 ms

Figure 12: Stroboscopic images of streamlines: Roll rotational flight.

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Masahiro Shindo, Taro Fujikawa, and Koki Kikuchi

Figure 13: Time history of twist angles: Roll rotational flight.

5. Conclusion In this paper, we analyzed vortices around the wings of a butterfly based on computational fluid dynamics using a three-dimensional high-speed camera information and clarified the posture control mechanism of a roll rotation. The results showed that the pressure distribution and behavior of the vortices changed according to the changes in attitude. In the case of a pitch rotational flight pattern, the pitch angle changed most significantly and the differential pressure concentrated near the leading edges of the fore wings.

The maximum reaction force on both

sides of the wing and the average angular moment about the pitch axis were 200mN and

− 32.0 µ Nm, respectively. In the case of a roll rotational flight pattern, the roll angle changed most significantly and the differential pressure was distributed across the whole wing.

The

maximum reaction force on the left wing was 400mN and that on the right wing was 220mN. The differential force generated an angular moment about the roll axis, which was − 282.0 µ Nm on average during flight.

These results show that a butterfly controlled its rotational direction

by changing the pressure distribution.

In future work, we need to analyze the long-term flight to clarify the posture stabilization mechanisms and validate it by deriving the flight experiment of ornithopter. *Corresponding author (Masahiro Shindo). Email address: s1376014we@s.chibakoudai.jp.

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0 ms

5 ms

13 ms

21 ms

27 ms

37 ms

44 ms

52 ms

58 ms

Figure 14: Stroboscopic images of the constant pressure surfaces: Roll rotational flight.

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Figure 15: Time history of the reaction forces: Roll rotational flight.

6. References Nestor O. Perez-Arancibia, John P. Whitney, Robert J. Wood, (2011). Lift Force Control of a Flapping-Wing Micro Robot, American Control Conference, 4761-4768.

Nestor O. Perez-Arancibia, John P. Whitney, Robert J. Wood, (2013). Lift Force Control of Flapping－Wing Micro Robots Using Adaptive Feed-forward Schemes, IEEE / ASME Transactions on Mechatronics, 155-168.

Fu-Yuen Hsiao, Lung-Jieh Yang, Sen-Huang Lin, Cheng-Lin Chen, Jeng-Fu SHEN, (2012).

Autopilots for Ultra Lightweight Robotic Birds－Automatic Altitude Control and System Integration of a sub-10g Weight Fapping-wing Micro Air Vehicle, IEEE Control Systems, 35-48.

Takahashi, H., Matsumoto, K., and Isao Shimoyama.

(2012).

Differential Pressure Measurement of an Insect Wing Using a MEMS Sensor. International Conference on Complex Medical Engineering, 349-352.

Fuchiwaki, M., Kuroi, T., Tanaka, K., and Tabata, T. (2013). Dynamic behavior of the vortex ring formed on a butterfly wing. Experimental in Fluid, 13-24.

Fujikawa, T., Sato, Y., Yamashita, T., and Kikuchi, K. (2010). Development of A Lead-Lag Mechanism Using Simple Flexible Links for A Small Butterfly-Style Flapping Robot.

WAC2010 (ICDES2005, MSSP2008, ISIAC2010), 1-6.

Fujikawa, T., Hirakawa, K., Okuma, S., Udagawa, T., Nakano, S., and KIKUCHI, K. *Corresponding author (Masahiro Shindo). Email address: s1376014we@s.chibakoudai.jp.

2014. American Transactions on Engineering & Applied Sciences. Volume 3 No. 4 ISSN 2229-1652 eISSN 2229-1660 Online Available at http://TUENGR.COM/ATEAS/V03/0233.pdf.

(2008).

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Development of a small flapping robot: Motion analysis during takeoff by numerical simulation and experiment. Mechanical Systems and Signal Processing, 22, 1304-1315.

Udagawa, T., Fujikawa, T., GAO, X., and Kikuchi, K. (2005). Development of a Small-Sized Flapping Robot. The 1st international conference on design engineering and Science, 283-288.

Dickinson, M., Lehmann, F., and Sane, S. (1999). Wing Rotation and the Aerodynamic Basis of Insect Flight. Science, 284, 1954-1960.

Lehmann, F., Sane, S., and Dickinson, M. (2005). The aerodynamic eďŹ&#x20AC;ects of wing-wing interaction in ďŹ&#x201A;apping insect wings. The Journal of Experimental Biology, 208, 3075-3092.

Masahiro Shindo is a graduate student of Department of Advanced Robotics, Chiba Institute of Technology, Japan. He received his degree in Engineering from Chiba Institute of Technology in 2013. He also received the Hatakeyama Award, the Japan Society of Mechanical Engineers in 2013.

He investigates the flight mechanism of a butterfly using a three-dimensional computational fluid analysis and an insect-scale flapping robot.

Dr. Taro Fujikawa is an Assistant Professor of Department of Robotics and Mechatronics at Tokyo Denki University, Japan. He received his Ph.D. in Engineering from Chiba Institute of Technology, Japan, in 2011. From 2011 to 2012, he was a Postdoctoral Researcher at Research Institute of Chiba Institute of Technology. He was a recipient of the Miura Award, the Japan Society of Mechanical Engineers in 2007, and the Best Paper Award of the 1st International Conference of Design Engineering and Science (ICDES2005). His research interests include biomimetic robots, mobility vehicles, and mechanical engineering design.

Dr.Koki Kikuchi is a professor of Department of Advanced Robotics, Chiba Institute of Technology, Japan. He received his Ph.D. in Engineering from Tokyo University of Science in 1999. He also received the best paper award of the International Conference of Design Engineering and Science (ICDES2005) from Japan Society of Design Engineering, JSDE, and the best paper award of journal of JSDE. He investigates mechanisms creating insect abilities and develops small robots such as a butterfly-style flapping robot, vertical wall climbing robot, on-water running robot, etc. based on insect scale physics.

Peer Review: The original of this article has been submitted to The 3rd International Conference on Design Engineering and Science (ICDES 2014), held at Pilsen, Czech Republic. The Paper Award Committee of ICDES 2014 has reviewed and selected this paper for journal publication.

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2014 American Transactions on Engineering & Applied Sciences.

American Transactions on Engineering & Applied Sciences http://TuEngr.com/ATEAS

Motion Analysis of Pitch Rotation Mechanism for Posture Control of Butterfly-style Flapping Robot Taro Fujikawa a b

a*

b

, Masahiro Shindo , and Koki Kikuchi

b

Department of Robotics and Mechatronics, Tokyo Denki University, JAPAN Department of Advanced Robotics, Chiba Institute of Technology, JAPAN

ARTICLEINFO

Article history: Received July 24, 2014 Accepted August 04, 2014 Available online August 08, 2014 Keywords: Flapping robot; Butterfly; Pitch rotation mechanism; Posture control; Pitch angle; Flapping angle.

A B S T RA C T

We developed a small flapping robot on the basis of movements made by a butterfly with a low flapping frequency of approximately 10 Hz, a few degrees of freedom of the wings, and a large flapping angle. In this study, we clarify the pitch rotation mechanism that is used to control its posture during takeoff for different initial pitch and flapping angles by the experiments of both manufactured robots and simulation models. The results indicate that the pitch angle can be controlled by altering the initial pitch angle at takeoff and the flapping angles. Furthermore, it is suggested that the initial pitch angle generates a proportional increase in the pitch angle during takeoff, and that certain flapping angles are conducive to increasing the tendency for pitch angle transition. Thus, it is shown that the direction of the flight led by periodic changing in the pitch angle can be controlled by optimizing control parameters such as initial pitch and flapping angles.

2014 Am. Trans. Eng. Appl. Sci.

1. Introduction Flying robots with various methods of lift and propulsion, such as unmanned air vehicles, airships, and multi-rotor helicopters, have been developed as observation systems because they are unaffected by ground conditions and have high versatility (Green 2006, Fukao 2003, and Holfman 2007). Although these robots exist in several sizes, smaller robots are effective for *Corresponding author (T.Fujikawa). Tel: +81-3-5284-5613 Fax: +81-3-5284-5698.

E-mail addresses: fujikawa@fr.dendai.ac.jp.

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passing through narrow spaces. Here, flying creatures whose wings have high flight capabilities such as ability to turn at right angles and to accelerate at more than 10 G from takeoff. The flapping mechanism of small flying insects is particularly useful for maneuvering through narrow spaces, such as gaps between debris. Although many insect-scale flapping robots have been developed thus far, they have not achieved practical flight (Deng 2006, Fearing 2000, Sitti 2001, and Wood 2008) because it is difficult to implement a heavy driving system such as a conventional actuator consisting of a motor, gears, and a battery in such a small body. In addition, the complexity of the link mechanism deteriorates the transmission efficiency because the viscosity factors such as friction are more dominant than inertia at this scale. To overcome such challenges, we developed a flapping robot modeled after a butterfly having a low flapping frequency of approximately 10 Hz and a few degrees of freedom (DOF) of the wings. This robot is equipped with a rubber motor as a lightweight actuator, which does not require converting electrical energy into mechanical energy. Furthermore, it contains a simple slider-crank mechanism with elastic links to enable a wide flapping angle. In our previous research (Udagawa 2007 and Fujikawa 2008, 2010), a manufactured flapping robot took off from an airspeed of 0 m/s and flew upward during the downstroke and then forward during the upstroke in a staircase pattern to mimic the flight trajectory of a butterfly. However, posture control was not realized.

Here, one of the characteristics of the butterfly-style flight is a posture control mechanism that raises the body pitch angle during the downstroke and lowers it during the upstroke, thereby synchronizing with flapping motion. Although, a butterfly has a few DOF of the wingsâ&#x20AC;&#x201D;control of its wings is complicatedâ&#x20AC;&#x201D;this insect flies skillfully.

Figure 1: Definitions of parameters used in motion analysis.

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Taro Fujikawa, Masahiro Shindo, and Koki Kikuchi

In this study, we analyze the periodical pitch rotation mechanism that affects the posture of a butterfly during the takeoff by using a manufactured flapping robot and numerical simulation.

Furthermore, we clarify the posture control mechanism to realize autonomous flight of the flapping robot.

Figure 2: Stroboscopic photographs of a butterfly captured during takeoff This paper is organized as follows: In section 2, we analyze the flight characteristics of a butterfly. In section 3, we describe the butterfly-style flapping robot and numerical simulation *Corresponding author (T.Fujikawa). Tel: +81-3-5284-5613 Fax: +81-3-5284-5698.

E-mail addresses: fujikawa@fr.dendai.ac.jp.

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model. In section 4, we analyze and discuss the pitch rotation mechanism of both robots and the simulation models. Finally, in section 5, we conclude the paper and outline future works.

2. Flight Characteristics of a Butterfly We analyzed the flight characteristics of a swallowtail butterfly (Papilio xuthus) during takeoff by using a 3-D high-speed camera system with a resolution of 640 × 480 pixels and 200 fps (Fujikawa, 2010). Figure 1 shows the definitions of parameters used in the motion analysis, and Figure 2 displays stroboscopic images of a butterfly captured during takeoff. The red line in Figure 2 denotes the trajectory of the center of the thorax.

Figure 3 shows a typical example of the relationship between flapping and pitch angles. As shown in the figure, the downstroke of the flapping begins at approximately 80 deg and the upstroke begins at approximately −60 deg; that is, a butterfly flaps its wings in asymmetric up-and-down motion. In addition, the pitch angle begins at approximately 20 deg and periodically changes with a phase difference of approximately 90 deg between the flapping and pitch angles. These results show that the asymmetric flapping angle and takeoff upon ascension affect the pitch rotation. It is thought that a butterfly controls its posture through effective management of these mechanisms.

Figure 3: Relationship between flapping and pitch angles during takeoff.

3. Butterfly-style flapping robot and numerical simulation model We manufactured a butterfly-style flapping robot and developed a numerical simulation model. The robot as shown in Figure 4, which was constructed in bamboo to be lightweight, is equipped with a rubber motor as an actuator for a high power–mass ratio. The wing membranes are thin films made of polyethylene. The slider-crank mechanism mounted on its rear translates the rotation of the actuator into the flapping motion of the wings. By bending the elastic links, a 254

Taro Fujikawa, Masahiro Shindo, and Koki Kikuchi

wide flapping angle such as that from 80 deg to (â&#x2C6;&#x2019;60) deg is obtained compared with using rigid links (Fujikawa, 2010).

Figure 5 shows the simulation model, the body of which consists of four mass points including the head, thorax 1, thorax 2, and abdomen, which are connected by springs and dampers. Both right and left wings are integrated with the respective fore and hind wings for synchronous movement. Each wing is divided in Nx-1 points along the wingspan direction and in Ny-1 points along chord direction, which are connected by springs and dampers. The finite element method (FEM) was used to calculate the body and wing motions and flow field around the wings; details have been previously documented (Fujikawa, 2008).

The manufactured robot was used in takeoff experiments to observe trajectories of the flight and transitions of its pitch angle. To analyze its lift, thrust, and pitch rotation moment around the center of mass, we used numerical simulation.

Wings

Elastic links

Slider-crank mechanism

Figure 4: Manufactured butterfly-style flapping robot

4. Motion analysis of pitch rotation mechanism 4.1 Parameters of flapping robots To analyze the flight characteristics for the pitch rotation mechanism, we manufactured three models. Model A has a flapping angle of 80 deg to â&#x2C6;&#x2019;60 deg, and an initial pitch angle of 15 deg based on the results of analysis of a butterfly. Model B has the same flapping angle as that of *Corresponding author (T.Fujikawa). Tel: +81-3-5284-5613 Fax: +81-3-5284-5698.

E-mail addresses: fujikawa@fr.dendai.ac.jp.

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Model A; however, its initial pitch angle is 0 deg. Model C has a flapping angle of 60 deg to â&#x2C6;&#x2019;80 deg and an initial pitch angle of 15 deg. The wing length and the chord length of each model are 53 mm and 42 mm, respectively, and the total mass of each model, including an actuator, is approximately 520 mg, which is equivalent to that of a butterfly.

Figure 5: Numerical simulation model We then performed experiments to clarify the following relationships for the takeoff motion by using a flapping frequency of 12 Hz for each model: (1)

For different initial pitch angles, a comparison experiment was conducted by using Model A and Model B.

(2)

For different flapping angles, a comparison experiment was conducted by using Model A and Model C.

Table 1 shows these experimental parameters.

Table 1: Parameters of flapping robots Model A Model B Flapping angle [deg] 80 ~ -60 80 ~ -60 Initial pitch angle [deg] 15 0 Flapping frequency [Hz] 12 12

Model C 60 ~ -80 15 12

4.2 Settings of Numerical Simulation Models The structural parameters of the numerical simulation models corresponded to those of manufactured flapping robot,

including a wing length of 53 mm, chord length of 42 mm, body

length of 38 mm (head 4 mm, thorax 10 mm, abdomen 24 mm), total mass of 520 mg (head 60 mg, thorax 150 mg, abdomen 210 mg, wing 100 mg), and wing thickness of a uniform 0.3 mm.

Taro Fujikawa, Masahiro Shindo, and Koki Kikuchi 256

Figure 6: Stroboscopic photographs of Model A captured during takeoff

Figure 7: Stroboscopic photographs of Model B captured during takeoff.

The computational scheme included the following parameters: wings were divided into Nx = 16 along the wingspan direction and Ny = 12 along the chord direction; node number of FEM *Corresponding author (T.Fujikawa). Tel: +81-3-5284-5613 Fax: +81-3-5284-5698.

E-mail addresses: fujikawa@fr.dendai.ac.jp.

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was approximately 700,000.

The computational space was set to be approximately 1,300 Ă&#x2014;

1,000 Ă&#x2014; 1,000 mm.

Figure 8: Transitions of pitch angles (left) and trajectories of center of mass (right) during takeoff of models A and B for manufactured flapping robot

Figure 9: Transitions of lift (left) and thrust (right) of models A and B by numerical simulation.

Figure 10: Transitions of pitch moment of models A and B by numerical simulation.

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Figure 11: Stroboscopic photographs of model C captured during takeoff.

Figure 12: Transitions of pitch angle (left) and trajectories of center of mass (right) during takeoff of models A and C for manufactured flapping robot

4.3 Results and discussion 4.3.1

Different initial pitch angle

Figures 6 and 7 show stroboscopic photographs of takeoff of models A and B, respectively, which were captured by a high-speed camera. Figure 8 shows comparisons of transitions of pitch angle and trajectories of center mass. Figures 9 and 10 show comparisons of transitions of lift, thrust, and pitch rotation moment, respectively, of models A and B by numerical simulation. *Corresponding author (T.Fujikawa). Tel: +81-3-5284-5613 Fax: +81-3-5284-5698.

E-mail addresses: fujikawa@fr.dendai.ac.jp.

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The experiments revealed that the transition of pitch angle increased at a rate proportional to the initial pitch angle (Figure 8, left). An increase in initial pitch angle to Model A resulted in stronger backward flight during the downstroke than that observed in Model B (Figure 8, right).

The maximum lifts of models A and B were 0.028 N and 0.029 N, respectively, and maximum thrusts were 0.011 N and 0.012 N, respectively, for backward direction during the downstroke.

Because the pitch angle at the beginning of the upstroke of Model A (42 deg) became larger than that of Model B (29 deg), the lift of Model A (â&#x2C6;&#x2019;0.024 N) increased over that of Model B (â&#x2C6;&#x2019;0.021 N). That is, the flight level was lower in Model B (Figure 9, left), and the thrust of Model A at 0.025 N was larger than that of Model B at 0.023 N for foreword direction at a stroke cycle of approximately 0.75 (Figure 9, right). However, as shown Figure 10, the transitions of the pitch rotation moment showed little differences between the models because the angles of the downstrokes and upstrokes of both models were equal.

4.3.2

Different flapping angle

We performed the same experiments to compare different flapping angles during takeoff.

Figure 11 shows stroboscopic photographs captured during takeoff of Model C. Figure 12 shows comparisons of transitions of pitch angle and trajectories of center mass of manufactured hardware. Figures 13 and 14 show comparisons of transitions of lift, thrust, and pitch rotation moment of simulation models, respectively.

The transition of pitch angle of Model C showed an increasing tendency compared to that of Model A (Figure 12, left). Therefore, Model C showed stronger backward movement during the downstroke and more upward movement during the upstroke (Figure 12, right). Moreover, the lift during the downstroke of Model C reached a maximum faster than that of Model A, and its value at 0.031 N was larger than that of Model A. During the upstroke, distinctive characteristics of the transitions of lift were noted. The lift of Model C reached a maximum faster than that of Model A; however, although the lift of Model A was always negative, that of Model C remained positive until approximately 0.75 strokes (Figure 13, left). This result occurred because the pitch angle at the beginning of the upstroke was more than 60 deg, and the direction of the reaction force of the wings became downward. Therefore, the force of the flapping during the upstroke generated the lift. Here the maximum lift of Model C was 0.005 N. For thrust during the downstroke, because the pitch angle of Model C became larger than that of Model A, the thrust of Model C shifted to positive at an earlier point, which was observed as backward flight, than that 260

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of Model A (Figure 13, right). During upstroke, because the pitch angle of Model C reached nearly 90 deg, its thrust was larger than that of Model A. The maximum thrusts of Model C during downstroke and upstroke were 0.007 N and 0.030 N, respectively. As shown in Figure 14, because the total pitch rotation moment of Model C was larger than that of Model A, its nose-up movement was also larger than that of Model A. Hence, the pitch angle of Model C was increased over that of Model A. However, if the pitch angle at the start of the second stroke becomes over 45 deg, reaction force of the wings during downstroke generates backward thrust and then hardware does a backflip. Therefore, it is necessary to control the body pitch angle over 45 deg at the end of downstroke and under 45 deg at the end of upstroke like a Model A in the case of level flight.

Figure 13: Transitions of lift (left) and thrust (right) of models A and C by numerical simulation.

Figure 14: Transitions of pitch moment of models A and C by numerical simulation.

5. Conclusion To realize posture control of a butterfly-style flapping robot, we analyzed the pitch rotation mechanism that occurs during takeoff by performing experiments of hardware and numerical *Corresponding author (T.Fujikawa). Tel: +81-3-5284-5613 Fax: +81-3-5284-5698.

E-mail addresses: fujikawa@fr.dendai.ac.jp.

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simulation for different initial pitch angles and flapping angles. We demonstrated that the pitch angle is controlled by the initial flapping angle at takeoff for increasing the angle and by different flapping angles to generate the increasing tendency in the transition of the pitch angle. Thus, it was shown that these parameters control the direction of flight.

In future research, we aim to investigate the mechanism for yaw and roll control to realize autonomous flight of a butterfly-style flapping robot.

6. Acknowledgements This research was partially supported by Research Institute for Science and Technology of Tokyo Denki University Grant Number Q13T-06/Japan. The authors would like to express their deep gratitude to all involved in the research project.

7. References E. W. Green and P. Y. Oh. (2006). Autonomous Hovering of a Fixed-Wing Micro Air Vehicle. Proceedings of 2006 IEEE International Conference on Robotics and Automation. 2164-2169.

G. Hoffman, H. Huang, et al.. (2007). Quadrotor Helicopter Flight Dynamics and Control: Theory and Experiment. Proceedings of 2007 International Conference on the American Institute of Aeronautics and Astronautics. 1-20.

M. Sitti. (2001). PZT Actuated Four-Bar Mechanism with Two Flexible Links for Micromechanical Flying Insect Thorax. proceedings of IEEE International Conference on Robotics and Automation. 3893-3900.

R. J. Wood. (2007). Design, fabrication, and analysis of a 3 DOF, 3cm flapping-wing MAV. proceedings of IEEE International Conference on Intelligent Robots and Systems.

1576-1581.

R. J. Wood. (2008). The First Takeoff of a Biologically Inspired At-Scale Robotic Insect.

IEEE Trans. Rob. 24(2). 341-347.

R. S. Fearing, K. H. Chiang, M. H. Dickinson, D. L. Pick, M. Sitti, and J. Yan. (2000). Wing Transmission for a Micromechanical Flying Insect. proceedings of IEEE International Conference on Robotics and Automation. 1509-1516.

T. Fujikawa, et al.. (2008). Development of a Small Flapping Robot -Motion Analysis during Takeoff by Numerical Simulation and Experiment-. Mechanical Systems and Signal Processing (MSSP). 22(6). 1304-1315.

T. Fujikawa, Y. Sato, T. Yamashita, and K. Kikuchi. (2010). Development of A Lead-Lag Mechanism Using Simple Flexible Links for A Small Butterfly-Style Flapping Robot.

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ISIAC2010.

T. Fukao, K. Fujitani, T. Kanade. (2003). An autonomous blimp for a surveillance system.

Proceedings of 2003 IEEE/RSJ International Conference on Intelligent Robots and Systems. 1829-1825.

T. Udagawa, T. Fujikawa, X. GAO, and K. Kikuchi. (2005). Development of a Small-Sized Flapping Robot. JSDE The 1st International Conference on Design Engineering and Science. 283-288.

X. Deng, L. Schenato, W. Chung Wu, and S. S. Sastry. (2006). Flapping Flight for Biomimetic Robotic Insects: Part I â&#x20AC;&#x201C; System Modeling. IEEE Trans. Rob.. 22(4).

776-788.

Dr. Taro Fujikawa is an Assistant Professor of Department of Robotics and Mechatronics at Tokyo Denki University, Japan. He received his Ph.D. in Engineering from Chiba Institute of Technology, Japan, in 2011. From 2011 to 2012, he was a Postdoctoral Researcher at Research Institute of Chiba Institute of Technology. He was a recipient of the Miura Award, the Japan Society of Mechanical Engineers in 2007, and the Best Paper Award of the 1st International Conference of Design Engineering and Science (ICDES2005). His research interests include biomimetic robots, mobility vehicles, and mechanical engineering design.

Masahiro Shindo is a graduate student of Department of Advanced Robotics, Chiba Institute of Technology, Japan. He received his degree in Engineering from Chiba Institute of Technology in 2013. He also received the Hatakeyama Award, the Japan Society of Mechanical Engineers in 2013. He investigates the flight mechanism of a butterfly using a three-dimensional computational fluid analysis and an insect-scale flapping robot.

Dr.Koki Kikuchi is a professor of Department of Advanced Robotics, Chiba Institute of Technology, Japan. He received his Ph.D. in Engineering from Tokyo University of Science in 1999. He also received the best paper award of the International Conference of Design Engineering and Science (ICDES2005) from Japan Society of Design Engineering, JSDE, and the best paper award of journal of JSDE. He investigates mechanisms creating insect abilities and develops small robots such as a butterfly-style flapping robot, vertical wall climbing robot, on-water running robot, etc. based on insect scale physics.

Peer Review: The original of this article has been submitted to The 3rd International Conference on Design Engineering and Science (ICDES 2014), held at Pilsen, Czech Republic. The Paper Award Committee of ICDES 2014 has reviewed and selected this paper for journal publication.

*Corresponding author (T.Fujikawa). Tel: +81-3-5284-5613 Fax: +81-3-5284-5698.

E-mail addresses: fujikawa@fr.dendai.ac.jp.

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2014 American Transactions on Engineering & Applied Sciences.

American Transactions on Engineering & Applied Sciences http://TuEngr.com/ATEAS

Design of Quadruped Walking Robot with Spherical Shell Takeshi AOKI a b

a*

, Kazuki OGIHARA

b

Department of Advanced Robotics, Chiba Institute of Technology, JAPAN Future Robotics Technology Center, Chiba Institute of Technology, JAPAN

ARTICLEINFO

Article history: Received July 24, 2014 Accepted August 08, 2014 Available online August 12, 2014

Keywords: Mechanical design; Transformable robot; Disaster robot; Rescue engineering; Basic robot experiments.

ABSTRACT

We propose a new quadruped walking robot with a spherical shell, called "QRoSS." QRoSS is a transformable robot that can store its legs in the spherical shell. The shell not only absorbs external forces from all directions, but also improves mobile performance because of its round shape. In rescue operations at a disaster site, carrying robots into a site is dangerous for operators because doing so may result in a second accident. If QRoSS is used, instead of carrying robots in, they are thrown in, making the operation safe and easy. This paper reports details of the design concept and development of the prototype model.

Basic experiments were conducted to verify performance, which includes landing, rising and walking through a series of movements.

2014 Am. Trans. Eng. Appl. Sci.

1. Introduction Recently, many mobile robots have been developed to investigate and perform rescue operations at disaster sites where it is difficult for operators to enter. Two examples are the 510 Packbot (iRobot 510 PackBot, 2013), a commercial product, and Quince (Rohmer et al., 2013), both of which are in practical use. We believe that wide range searches using many small, inexpensive robots dedicated to search operations are effective in finding victims quickly. *Corresponding author (Takeshi AOKI). Tel/Fax: +81-47-478-0392. E-mail address: takeshi.aoki@it-chiba.ac.jp.

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However, carrying robots into a disaster site is dangerous; operators may be injured carrying them in, resulting in a second accident. Throwing the robots in over uneven terrain results in a safer, easier way of getting the robot into the site. Various search robots that can be thrown have been developed for military or security use. The packbot 110 FirstLook, made by iRobot, is a small type crawler vehicle with two flipper arms; it can climb over obstacles using its arms (iRobot 110 FirstLook, 2013). The SandFlea, made by Boston Dynamics, is a small wheel type vehicle comprising four wheels and a jump mechanism. It can move and jump over high steps using gas power (Boston Dynamics SandFlea, 2013). The Throwbot, made by Recon Robotics, comprises a column body and two wheels. It can be operated by wireless controller (Recon Robotics Throwbot, 2013). Each of these robots is small, very lightweight and resistant to shock.

Their wheels or crawler belt on the ends of their body and absorbs shock, so landing on a flat surface is fine. However, landing on uneven surfaces such as rubble in a disaster site causes shock to the robot body. We believe this robot needs shock absorbent materials that can withstand external force from all directions.

Walking robots can contact the ground over discrete points and the contact points can be arbitrarily selected according to terrain features. Recently, some robots have been field tested on uneven terrains with good results. The LittleDog (Buchli et al., 2009) and The BigDog (Boston Dynamics BigDog, 2013) are well-known quadruped walking robots made by Boston Dynamics; performance was tested by having them walk on easily collapsed rubble and on a mountain surface. The Titan X (Hodoshima et al, 2010) is a hybrid quadruped Walking Robot with the mobility of a crawler vehicle. Each leg mechanism has a crawler belt that can also be used as a drive train. The Titan X demonstrates proper performance over irregular ground using crawler mode and walking mode. Previous robots did not have a shock-proof function to protect the robot when it falls. Consequently, it was difficult for them to walk over irregular ground. Neither did they have the kinematic performance needed to recover from a fall.

We propose and aim to develop a new quadrupedal walking robot called "QroSS," which has a spherical outer shell and features walking mode and shock-proof mode. The mechanical design is reported here. The remainder of this paper is organized as follows: Section II overviews and discusses the design concept; Section III gives details of mechanical design; Section IV presents considerations on rising motions; and Section V presents and discusses basic experiments.

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2. Design Concept We assume the following rescue scenario for our robot, shown in Figure 1: a) getting investigation robot into disaster site from safe area by throwing, b) landing on rubble while absorbing shock, c) rising by extending its legs, and d) investigation by walking mode. QRoSS design requirements are that it must be shock absorbent, mobile and recoverable.

Figure 1: Application concept of our robot

Figure 2: Spherical shell for shock-proofing.

Figure 3: Omni-directional design for fall posture.

2.1 Basic Design Concept A spherical outer shell can receive external force from all directions, such as that shown in Figure 2. It is difficult for a rectangular solid shape to absorb landing shock completely on uneven surfaces. Many mobile robots have been proposed that have a ball outer shape and can roll through movement of a C.O.G. inside the outer shell. Traveling performance of these robots, *Corresponding author (Takeshi AOKI). Tel/Fax: +81-47-478-0392. E-mail address: takeshi.aoki@it-chiba.ac.jp.

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however, is low because reaction force of the rotating outer shell cannot be received with only the inside moment of the C.O.G. For that reason, we propose a quadruped walking robot with a spherical shell; it can change from ball mode to walking mode. With the common design of previous walking robots, because of the up and down directions, a rising mechanism is required when the robot lands upside down. directions.

We propose a new design concept that has no up and down

This is done by expanding the working range of each leg in the vertical direction

(Figure 3).

2.2 Design of Spherical Shell The transformable design from a ball shape to a walking mode is an old idea from ancient times. Two examples are “HARO,” a bipedal robot in Gundam, and “Destroyer droid,” a tripedal robot in Star Wars. These robots are unique mechanisms and achieving them has been difficult.

The MorpHex III is a transforming Hexapod Robot that can be changed to ball mode, hexapod walking mode and rotational transfer mode by leg actuators and a body actuator (Halvorsen, 2013). However, because the ball shape is formed by the leg mechanisms, it cannot withstand external force that impacts its spherical surface. Even if it uses a structure in which the outline of the leg mechanisms can receive force, designing it to be lightweight enough for a mobile robot is difficult.

Figure 4: Structure of spherical shell of QRoSS. We propose making the spherical outer shell and the walking mechanisms independent of each other. By doing so, our robot can achieve both functions: mobility of the legs and resistance to external shock. It can also be made small and lightweight. We designed the outer shell of the QRoSS with an outer spherical cage, rubber absorbers and a center pole with coil springs, shown in Figure 4. The cage is structured of wires featuring super elasticity. The center pole connects the outer cage through the absorbers, and the center frame, which is a base of legs, floats on the center pole over coil springs. With this structure, QRoSS can absorb external shock.

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2.3 Design of leg mechanism QRoSS’s legs must be mounted between the super elasticity wires of the spherical cage. The common joint arrangement of a quadruped walking robot, which is a spider type robot, is type A of Figure 5. However, the cage prevents work space of leg motion which swings along the horizontal plane. Therefore, because the legs must swing outside the cage, type B or type C of Figure 5 can be chosen. Because both types need a large work space for the knee joint – almost 360 degrees to achieve the omni-directional design in the vertical direction and storage legs in the shell – the knees must be double-jointed. However, type C cannot store the legs in the shell and the knee and the end part of the shin are outside, as shown in the upper figure of Figure 6. This is the case because type C cannot use the inside space of the shell effectively. Type B can move the shin part into the center area using the horizontal axis of the knee joint, shown in the lower figure of Figure 6. Thus, QRoSS uses the type B joints arrangement of the leg mechanisms.

Figure 5: Arrangement of joint axes.

Jumping robot (Kovac et al., 2009) has an outer cage and can jump on two legs; the cage can absorb external forces. This robot can roll over and return to its basic posture through the center of gravity effect, which is decentered. However, it cannot use outer its outer shell to travel; it uses only its legs. The QRoSS can use the outer shell as an extra contact point and to climb over high steps.

3. Mechanical Design of QRoSS Figure 7 is the first prototype model of the QRoSS and Table 1 lists specifications. The prototype model comprises the spherical outer shell and four legs; each leg is arranged radially from the center of the shell. Thus, the QRoSS does not have directivity in either the vertical direction or horizontal direction in preparation for landing on a complicated geographical surface. *Corresponding author (Takeshi AOKI). Tel/Fax: +81-47-478-0392. E-mail address: takeshi.aoki@it-chiba.ac.jp.

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Moreover, it can move using rotation of the spherical shell. This rotational torque is bigger than that of a rotational ball robot because the legs can receive the reaction force of the shellâ&#x20AC;&#x2122;s rotational torque. Each leg has three active DOFs: each actuator is a servo motor â&#x20AC;&#x201C; a Futaba RS303MR with Maximum torque of 6.5[kgf-cm].

Battery is a Li-Fe battery (2 cells, 6.6[V],

300[mAh]); its running time approaches ten minutes.

Type C of joints arrangement: Leg structures overflows from the shell.

Type B of joints arrangement: The space in the shell can be used effectively.

Figure 6: Difference in storage states of joint arrangement of legs

Figure 7: First prototype model of QRoSS. 270

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Table 1: Specification of QRoSS. Height 247[mm] Width 240[mm] Diameter of spherical shell 210[mm] Mass (Including battery) 1039[g] DOFs 12 Actuators Futaba RS303MR Ground clearance 40[mm] Walking speed 140[mm/s]

Load is acted in front of a wire of the spherical outer shell

Load is acted in between wires of the spherical outer shell Figure 8: Structural analysis of spherical shell.

3.1 Spherical Outer Shell The outer shell is structured as a cage, which is 210[mm] diameter and comprises twelve wires, with a center pole through the absorbers.

The wires of the cage are super elasticity rods â&#x20AC;&#x201C;

made of titanium alloys and a shape memory alloy. deformation does not reach the plastic region.

Therefore, when shocked from the outside,

At both ends of the super elastic rods, the amount

*Corresponding author (Takeshi AOKI). Tel/Fax: +81-47-478-0392. E-mail address: takeshi.aoki@it-chiba.ac.jp.

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of absorbable shock is small because deformations are restricted by connections to the hub.

To

absorb the shock in this part, the absorbers, which are made of a polyurethane foam, are arranged between the wire hub and the center pole.

Because an axial direction of the center pole has no

modification element (like an elastic rod) the center frame is floating, mounted on the pole by coil springs; it can slide on the surface and absorb the shock of an axial direction.

To select the wire diameter of the spherical shell, simulation of the structural analysis was performed using Autodesk Inventor.

In this simulation, a static load of 800[N] was applied to

the simulation model of the shell. This load is an equivalent value of an impact force: a robot's mass is set to 2[kg] and it is dropped from a height of 2[m] in free fall and an adsorption distance of 50 mm. From the analysis result, the wire diameter of the super elastic rod is set at Ď&#x2020;2.3[mm], and 12 wires are used. This diameter is the largest size that can be purchased.

The upper figure

of Figure 8 illustrates receiving force from the front of a wire, and the following figure illustrates receiving force from a place where the interval of wires is the largest to expand leg mechanisms toward the exterior. Although deformation is too large when load is applied between wires, because the wire diameter is the maximum we can buy, we decided to make up for it by limiting the weight and distributing shock.

3.2 Leg Mechanism The leg mechanisms must be designed for an up-and-down symmetrical work space and stored in the outer shell. Taking into account modification of the cage of the spherical outer shell, the clearance between the leg and the cage is prevented when the rods are modified. We therefore decided to select a double joint mechanism. The upper picture of Figure 9 is the prototype model of the leg mechanisms. Each joint is called first, second and third joint from a base joint of the body (Figure 9). At the third joint, the activity and the passivity joints can be driven as same angles by combining two gears, which have the same number of teeth, to fold the legs completely.

Moreover, to be able to move the legs on the outside of the shell and prevent them from interfering with the wires of the cage when QRoSS is in walking mode, the second joint is arranged at the center of the leg to twist. Futaba RS303MRs are chosen as actuators of the leg joins; RS303MRs use serial communications and several servo motors can be operated through a single serial communication port of a micro controller. We designed the legs according to the specifications of this servo motor, in spite of its small output torque of only 6.5[kgfｼcm]. Small size and the ability to use serial communication were the most important reasons for selection.

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Each length of the leg mechanism is as follows: from the first joint to the passive joint of the third joint is 50[mm]; from the passivity joint to the activity of the third joint is 28[mm]; and from the activity joint to the end of the leg is 110[mm].

Figure 9: Prototype model of leg module.

Figure 10 shows the work ranges of the prototype is that leg mechanism. The work ranges in the vertical direction and the horizontal direction exceed 180 degrees, large enough to achieve operations.

To verify the work range of the leg in walking based on the CAD model of the

designed whole body, the range of the landing area of the end point of the leg, which changes with the height from the ground to the robot, was checked. Figure 11 shows the range on which the end point of the leg can land with the height of the robot. Results show that generations of walking motions are possible through planning the straight line paths required for walk operation in each circle.

Top view Side view Figure 10: Work range of leg module. *Corresponding author (Takeshi AOKI). Tel/Fax: +81-47-478-0392. E-mail address: takeshi.aoki@it-chiba.ac.jp.

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Figure 11: Results of paths of legâ&#x20AC;&#x2122;s end point.

3.3 System Configuration Figure 12 shows the system configuration of the prototype model of QRoSS. We did only tele-operation because the purpose of this experimental model is to verify mobilities. QRoSS is controlled by one micro controller, the mbed NXP LPC1768 with a USB Bluetooth module.

These micro controllers produce the paths of the legs and command values for servo motors of the legs and communicate using RS485 serial communication protocol. Inclination of the body is always detected by the accelerometer and the deployment direction and rising direction of the legs are controlled. The prototype model is operated from a PlayStation 3 video game pad, using wireless LAN.

Figure 12: System configuration of prototype model.

4. Consideration of Rising Motion The rising motion of the QRoSS is achieved by the motion path of the legs. Because it 274

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cannot detect the contact point with the ground when it lands on rubble, it needs to rise by motion of the legs from every state. We should divide and take into account rising motion and standing motion, because the actuators of the legs have only small outputs. In considering the work ranges of the legs, the QRoSS needs to perform standing operation where contact points of the foot are near the outer shell. There is no directivity in the body of the QRoSS; however, the direction in which the legs are to be folded up is decided when the legs are stored. The state in which it cannot rise by one series motion exists depending on the body posture. The left figure of Figure 13 is a schematic illustration of the QRoSS in two-dimensional display; it is a rotational state.

Where φ is an attitude angle of the body, L0, L1, and L2 express each link of the leg, and θ1 and θ2 express the first joint and the third joint. When the grounding point of the spherical shell is the origin of x-y coordinates, the contact point of the leg is set to X and Y. If the tip of the foot has reached the ground, formulas (1) and (2) are materialized.

X = L0 cos ϕ + L1 cos(θ1 − ϕ ) + L2 cos(θ 2 − θ1 + ϕ )

(1)

Y = R − L0 sin ϕ + L1 sin(θ1 − ϕ ) + L2 sin(θ 2 − θ1 + ϕ )

(2)

Rotational state

Starting state

Figure 13: Two-dimensional model of QRoSS Although there are times when the tip of the foot may not reach the ground, the motion is not affected because the C.O.G. of the robot is at near center. If Y=0, the foot is on the ground, and x can be estimated, shown in the right figure of Figure 13. When x≥0, the QRoSS can rotate and rise in the CCW direction in a single motion. When x<0, however, by deploying the legs in the side direction of the shell, rotation is in the CW direction once, and rising occurs by slipping and closing the tip to the shell. Figure 14 is the result of estimating the border value of the rotating *Corresponding author (Takeshi AOKI). Tel/Fax: +81-47-478-0392. E-mail address: takeshi.aoki@it-chiba.ac.jp.

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direction; the horizontal axis is φ and the vertical axis is X. The parameters are as follows: L0=40[mm], L1=50[mm], L2 =120[mm] and θ1=90[deg] whose value can be fixed near the border state. The border value is 78.7[deg]. As the graph shows, the border line is 78.7[deg], the QRoSS can rise with a single motion at the left side of the line; at the right side, however, double motions are required. Because it needs the double motions to roll over in more than half the conditions, the double motion is adopted in the rising motion.

Figure 14: Rotational direction depending on attitude angle.

5. Experiments and Discussion Three performance experiments were conducted to verify effectiveness of our design concept. In this experiment, because the current of the servo motor could not be measured correctly, quantitative evaluation was not done. Because an external power cable and wire communication would prevent mobility of the experimental robot, the experiments were made using an internal battery and wireless controller. For those experiments, the motion paths – rising motion and crawl locomotion – were prepared as the basic motion paths.

The first experiment is verification of deployment of the leg mechanism from a spherical shape and the rising operation. In deployment operation, the legs are expanded after the accelerometer detects direction of the ground when all legs are stored (No.1 of Figure 15) from No.2 to No.3: all legs are expanded from the outer shell in the horizontal direction. The posture changes into a state in which it is easy to do rising operation with four legs from the state of fall posture by this operation. In rising operation, the posture can be changed and risen through paddling motion of the leg. To reduce overload torque at the third joint, the legs once put above the landing point of the tip of the feet, as in No.4, descend to the ground verticality, and the 276

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QRoSS finishes standing up, as in No.5. This results in confirming one series performance of rising operations.

Figure 15: Deployment legs and rising

Figure 16: Return from fall state by autonomous system. *Corresponding author (Takeshi AOKI). Tel/Fax: +81-47-478-0392. E-mail address: takeshi.aoki@it-chiba.ac.jp.

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Figure 17: One series operation of rescue mission The second experiment confirms rising operation of the autonomous system when the robot falls. Figure 16 is the result of the second experiment. Even when the posture of the QRoSS is in fall down and the reverse state, the accelerometer detected the situation, and the robot could rise by autonomous operation, confirming validity.

The third experiment confirms a series operation of the rescue missions. The following operations were performed as a series operation: throwing onto a flat surface, deployment of the legs, rising and walking, and turning by crawl locomotion. Figure 17 shows the result of the third experiment, a series of planning operations was demonstrated. In crawl locomotion of the walking mode, because the center of gravity is contained in the triangle consisting of landing points of supporting legs, stable walk is possible; maximum walking speed was 140[mm/s]. In this report, a prototype of the QRoSS was developed and validity of the design concept was confirmed. Because the return from the fall state becomes easy using a spherical outer shell, this 278

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robot can challenge travel on more difficult surfaces. However, because the first prototype model was small, large output torque of the actuators could not be analyzed and the length of the legs was restricted. Consequently, in this first prototype, locomotion has not been tested using the spherical shell. We believe that hybrid locomotion using the outer shell is an effective way of achieving mobility on uneven terrain. In future work, the second prototype model will be large enough to use actuators with sufficient output torque. And we want to demonstrate the robot at an actual disaster site and thereby prove validity.

6. Conclusion We proposed a quadruped walking robot (QRoSS) with a spherical shell and developed a first prototype model. QRoSS is a transformable robot and can change from the storage state in which four legs are stored in the spherical shell to deploy the legs outside the shell. The shell not only absorbs external forces from all directions, but also improves mobile performance by virtue of its round shape.

This paper discussed the QRoSS design concept, functional design,

structural design, and arrangement of the joints. Development of the first prototype model with the structural analysis of the cage was explained. Finally, we proved effectiveness of the prototype performance through basic experiments.

7. References iRobot

510 PackBot, available from <http://www.irobot.com/us/learn/defense/packbot/ Details.aspx>, (accessed 2013-12-27) .

Rohmer, E., Ohno, K., Yoshida, T., Nagatani, K., Koyanagi, E., and Tadokoro, S. (2013).

Integration of a Sub- Crawlers' Autonomous Control in Quince Highly Mobile Rescue Robot. Proc. of Int. Conf. on Robotics and Automation, 78-83. iRobot 110 FirstLook, available from <http://www.irobot.com/us/robots/defense/firstlook/ Details.aspx>, (accessed 2013-12-27).

Boston

Dynamics SandFlea, available from robot_sandflea.html>, (accessed 2013-12-27).

<http://www.bostondynamics.com/

Recon Robotics Throwbot, available from <http://www.reconrobotics.com/products/Throwbot _XT_audio.cfm>, (accessed 2013-12-27).

J. Buchli, M. Kalakrishnan, M. Mistry, P. Pastor and S. Schaal. (2009). Compliant quadruped locomotion over rough terrain. Proc. of Int. Conf. on Intelligent Robots and Systems, *Corresponding author (Takeshi AOKI). Tel/Fax: +81-47-478-0392. E-mail address: takeshi.aoki@it-chiba.ac.jp.

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814-820.

Boston

Dynamics BigDog, available from _bigdog.html>, (accessed 2013-12-27).

<http://www.bostondynamics.com/robot

Hodoshima, R., Fukumura, Y., Amano, H., and Hirose, S. (2010). Development of Track-changeable Quadruped Walking Robot TITAN X -Design of Leg Driving Mechanism and Basic Experiment-. Proc. of Int. Conf. on Intelligent Robots and Systems, 3340-3345.

K.

Halvorsen. Morphex III. available from <http://www.robotee.com/index.php/ innovation-contest-winner-hexapod-morphex-31007/>, (accessed 2013-12-27).

M. Kovac, M. Schlegel, J.C. Zufferey and D. Floreano. (2009). A Miniature Jumping Robot with Self-Recovery Capabilities. Proc. of Int. Conf. on Intelligent Robots and Systems, 583-588.

Dr. Takeshi Aoki is an Associate Professor of Department of Advanced Robotics of Chiba Institute of Technology. He received his PhD in Engineering from Tokyo Institute of Technology in 2004 and was a researcher of the Tokyo Tech from 2004 to 2010. His current interests encompass mobile robots on uneven terrain, quadruped walking robots and rehabilitation tools.

Kazuki Ogihara is a Research Scientist of the Future Robotics Technology Center of Chiba Institute of Technology. He received the B. E. degree from Department of Advanced Robotics of the CIT in 2002. His current interests encompass rescue engineering, which is development of investigation robots in nuclear power plants, and a personal mobility.

Peer Review: The original of this article has been submitted to The 3rd International Conference on Design Engineering and Science (ICDES 2014), held at Pilsen, Czech Republic. The Paper Award Committee of ICDES 2014 has reviewed and selected this paper for journal publication.

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American Transactions on Engineering & Applied Sciences http://TuEngr.com/ATEAS

Enhancement of Space Environment Via Healing Garden a

Ooi Say Jer and Fuziah Ibrahim a

a*

School of Housing, Building and Planning, Universiti Sains Malaysia, MALAYSIA

ARTICLEINFO

Article history: Received August 24, 2013 Received in revised form August 29, 2014 Accepted September 10, 2014 Available online September 15, 2014

Keywords: Garden element; Therapeutic landscape; Healing factors; Garden design.

ABSTRACT

Green nature, sunlight and fresh air have been known as important component of healing in healthcare facilities. This paper presents the finding of an exploratory study on healing garden elements in healthcare facilities. The purpose of the paper is to find the elements of healing gardens and its healing factors in the existing garden design. In conducting this research study, site observation and informal interview at selected healthcare facilities have been performed. The study reveals the elements of existing garden design, the interactivity and the end users expectation on a garden. The finding shows that lacking some of the elements of garden design lead to less user friendliness and interactivity in the garden.

It also shows that the visibility, accessibility, quietness and comfortable condition in the garden give impact to the utilization of the garden.

2014 Am. Trans. Eng. Appl. Sci.

1. Introduction The article highlights an exploratory study on the elements of garden and how they contribute to healing in general. The exploration would focus on two gardens with different design at two hospitals in Penang, Malaysia. The main methods of data collection were observation and informal interview with the patrons. The patrons were the patients and visitors at the garden. The study requires the exploration of the garden design and usersâ&#x20AC;&#x2122; experience, their expectation to the garden and how garden affect them. The study was a respond to Hartig and Marcus (2006) who emphasis *Corresponding author (Fuziah Ibrahim). Tel/Fax: +60-4-6532834. E-mail address: fuziah@usm.my.

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that garden is a combination of a place with process. Dilani (2001) also claims that the garden is to benefit all users either in general nor specific needs.

According to American Horticultural Therapy Association (2007), garden is a plant dominated environment with nature aspect such as plantations, flowers, waters and other aspects. It is a designed place for users to respite and relax. According to Marcus (2007), the meaning of the word “healing” in healing garden is not meant to “cure” and will not cure hard diseases or any physical damages but it can reduce stress to more balanced state, to build up self-confidence, to provide an environment for therapeutic program with patients and provide an alternative place for visitor from hospital interior.

The history and evolution of healing garden is being a long age and the significant of healing garden can be group into three by its goals and users (Sandel, 2004). The first group is vocational programs. It is design for skill and personal development and the goal is for work adaption and leadership modeling. The main purpose of the program is to help users recover from injures, sickness or disabilities and help users regain and involve into social activities. The main target of the program is employees. Sandel (2004) claimed that the second program is therapeutic program which collaborate with vocational program and is for self-development. The target of this program is more on a group, unlike vocational program which targeted on personal development. The therapeutic program showed effect and helped participants built their self-confident and social soft-skill through various method. The last program is social program which help maintaining personal physical and psychological recovery. The design of the garden under this concept only implements horticulture activities as recreational activity. Many garden designs in hospitals apply social program.

First systematic Post Occupancy Evaluation study on gardens in hospital are conducted in the San Francisco Bay Area in the United State in 1994 and the result shows that ninety percent of garden users experienced a positive change of mood after time spent outdoors (Marcus and Barnes, 1995).

According to Ulrich (1999), there is probably advantages and four potential advantages to healthcare facilities which is the reduction of stress in patients, staff and visitors, to reduced pain in patients, the reduction in depression, higher reported quality of life for chronic and terminally-ill 282

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and improved way-finding (especially if garden in prominent location). Besides, the potential advantages of healing garden to healthcare facilities is to reduced costs, the length of staying for certain patient categories will be shorter and fewer strong pain medication doses will be taken. The other potential advantages are to increased patient mobility and independence, and would increase patient and staff job satisfaction. Ulrich (1999) also claims that healing garden does not only give advantages to the patients, but also to the staff, who working in stressful jobs and difficult conditions. With staff hiring and retention an increasing problem in many Western countries, improving the work environment, includes providing outdoor space for breaks, can be an important investment.

2. Element of Healing Garden According to Marcus (2007), there are potential activities for users in garden which is viewing, sitting, walking, resting, meditation praying, receiving therapeutic program, reading, playing and sporting. Ulrich (1999) also states that there are four basic garden design guidelines with intent to use garden to reduce userâ&#x20AC;&#x2122;s stress in the Roger Ulrichâ&#x20AC;&#x2122;s Theory of Supportive Garden Design.

The first basic guideline would be to provide opportunities for movement and exercise.

Exercise is a combination of movement with physically and psychologically benefits, to improve cardio-vascular health and stress reduction among adults and children (Brannon and Feist, 1997; Koniak-Griffin, 1994). In this theory, setting with looped pathway system offer shorter and longer routes for user with few different functions. The first function is setting which facilitate physical therapist for outdoor therapeutic activity. The second function is setting which allow children running and playing and the third function is setting for contemplative walking (i.e., a maze) and for users to walk or jogging. The last function is setting with landscape for post-surgery exercise.

Ulrich (1999) claim that the second guideline should provide opportunities to make choices, seek privacy and experience a sense of control. Patient in hospital is experiencing limitation of freedom (Ulrich, 1999). Stress from limitation of freedom shows negative reaction on immune system functioning among patients and will decreased staff motivation. An interview with garden user shows that one of the major motivations for using garden is regaining freedom and reducing stress (Marcus and Barnes, 1995). As garden is to reduce user stress by sense of control, users *Corresponding author (Fuziah Ibrahim). Tel/Fax: +60-4-6532834. E-mail address: fuziah@usm.my.

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explore with the entire access able route and users must able to make decision by their own on which pathway they prefer, therefore, the design must offer different choices â&#x20AC;&#x201C; place to be alone or with others; place to sit under sun or shade; place with broad or narrow view; fixed or moveable seating; different length of walking routes.

The third guideline claim by Ulrich (1999) is the garden design should encourage people gather together and experience social support. Research shows that higher level of social support will improve stress reduction and recovery rate for various medical conditions than isolated ones(Ulrich, 1999). The design is suggested to locate garden close to patient room, waiting area and main entrances in provide moveable seating, sub-space for small group to find privacy and to provide areas with tables and chairs for family and staff group to having meal together.

The last guideline is to encourage positive distractions with nature. According to Ulrich (1999), healing garden can have the effect to calm the mind, awakening the senses, stress reduction and can assist user to master their inner healing resources. To provide maximum therapeutic benefits, garden design must have multi ranging supply of plant material, i.e. with seasonal changes, subtleties of color, texture and shape. The design must also provide views to sky, trees can attract wildlife, and elements reflect sound of moving water.

Besides, there are another six requirement suggests by them to be consideration in garden design to reach gardenâ&#x20AC;&#x2122;s full potential which is visibility, accessibility, familiarity, quiet, comfort and unambiguously positive art.

Under the visibility requirement, it stated that there are only three of over hundred acute care hospital included signage to outdoor garden or roof garden in their way-finding system. The design of outdoor space is recommended locating near building entrance or visible from main foyer so that users can access to garden easily without helps of signage.

The second requirement is accessibility. It stated that the garden must be used by all ages and abilities. The wide of pathway must be wide enough for two wheelchairs to pass horizontally (minimum of six feet) at the same time. The paving joints should be narrow enough so as not to harm to catch a cane, wheelchairs or IV-pole. Access to outdoor spaces are keep locked in many hospital to reduce use or maintenance. However, accessibility can be enhanced by have good visual access to garden from indoor.

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The third requirement claim by Ulrich et el.(1999) is familiarity. Many seek for familiar and comforting environment while in stressful condition. In medical setting, those who are sick or in anxiety may need to access to garden setting to relieve. They claims this is especially important in the hospices for terminally ill.

The forth is quietness. According to Marcus and Barnes (1995), a study of four hospital gardens found that users are disturbed by mechanical sound such as air conditioners and street traffic. Garden user need to feel calm and relax, and be able to feel the wind, the sound of the fountain, even sound of birds. Hence, the location of garden must be away from traffic, parking space and machinery room.

Comfort is one of the requirements. The garden design need to provide physiological comfort and psychologically secure for users - with choices of places to sit under sun or shade; seating which allowed sprawl or lie down; seats with arms and backs; paving material do not cause excessive glare; a special patio for smokers to separate from non-smoker users.

And the last requirement is unambiguously positive art. According to Niedenthal et al. (1994), people trend to project their stress onto nearby objects and people while anxiety and discomfort experienced inside have developed “emotional congruence” which mean the attention of a person will focus on those parts that match the viewer’s emotional state. Ulrich (1999) also state that the scene may be seen as interesting or discomfort experience by the non-stress person. Hence in place which may increase level of stress especially in hospital, the design elements must be unambiguously positive in their message. Complex sculpture design may be appropriate in museum or corporate setting but is not appropriate in hospital. A research shows that recovery rate of heart surgery patients which exposed to landscape photographs is higher and had lower anxiety and fewer doses of strong pain killer compare with other patients with no pictures (Ulrich, et al., 1999). Ulrich also state that a classic case of in appropriate sculpture design in one of the hospital in United State where abstract figures of birds in courtyard cause dislike and fear emotion by cancer patients in adjacent wards and is been removed.

*Corresponding author (Fuziah Ibrahim). Tel/Fax: +60-4-6532834. E-mail address: fuziah@usm.my.

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3. Methodology The methodology chosen for the preliminary study of garden was the observation method.

According to Guba and Lincoln(1994), observation methods can span paradigms in research, from structured observations to highly unstructured participant observation. They quoted that question of method should be secondary to questions of paradigm, which can guides the investigation, not only in choices of method but in ontologically and epistemologically fundamental ways.

Hammersley and Atkinson (2007) also claim that observation as a methodology clearly contributes to these understandings, as it can be employed in â&#x20AC;&#x2DC;naturalâ&#x20AC;&#x2122; settings, rather than those set up for research purposes such as interviews. And Walshe et.al (2001) claim that observation methods have advantages when the focus of research is on understanding actions, roles and behaviour. They claim that interview allowed patrons said what they did but an observation allowed researchers to see directly what patrons done.

Both hospitals were chosen for the preliminary study because they have specific therapeutic garden. Observations were made during the day. In the same time, a few of those who visited the gardens were informally interviewed in order to understand the reason they visited the space and their expectation of a garden.

4

Result and Discussion

4.1 Observation at Hospital Seberang Jaya, Pulau Pinang Hospital Seberang Jaya is located at Seberang Perai Tengah district in Penang state. It started operating since October 1991 to serve people from Seberang Perai district especially people from Seberang Jaya area. Hospital Seberang Jaya is strategically located near to the North-South Expressway (PLUS) and the Butterworth-Kulim Expressway (BKE). The location is also near to the Prai Industrial Park, Bukit Mertajam City and Butterworth City. (Portal Rasmi Hospital Seberang Jaya, 2013). Figure 1 is a schematic plan shows the location of the hospital with its building arrangement.

Figure 2 (a) shows the main entrance and signage at main gate of the therapeutic garden. The main entrance is located in front of the hospital main road. The garden is visible and obviously seen by public. Figure 2 (b) shows the main route at the main entrance for the garden whereas Figure 2

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(c) and (d) shows the walkway in the garden. The route design is accessible for all ages and abilities. The pathway is accessible for wheelchair users as the width is about six feet. The paving joints in the garden are narrow enough so will not harm or catch a cane, wheelchairs or IV-pole.

Figure 1: The schematic plan of the healing garden in Hospital Seberang Jaya.

Figure 2: (a-b) The main entrance; (c-d) The walk way in the garden There are three pavilions in the garden. Figure 3 (a) and (b) shows the outlook of one of the pavilion. Figure 3 (c) and (d) shows the interior view in the pavilion. Figure 3 (c) shows that the route into the pavilion is designed accessible for wheelchair user and seat is provided in the *Corresponding author (Fuziah Ibrahim). Tel/Fax: +60-4-6532834. E-mail address: fuziah@usm.my.

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pavilion. Figure 3 (d) shows there is dustbin provided in the pavilion for user handling their disposal. Figure 3 (e) and (f) shows there are visitors resting inside the pavilion. The pavilion provided space for users to sit rest and to calm down.

(a)

(b)

(c)

(d)

(e) (d) Figure 3: (a-b) pavilions in the garden; (c-d) interior view of pavilion; (e-d) activities in pavilion

(a)

(b) (c) Figure 4: (a) Water fountain in the garden; (b-d) Facilities in the garden

(d)

Figure 4 (a) shows the water fountain in the garden. The sound of water would give a calming effect on the people and would encourage positive distractions with the nature. Figure 4 (b) shows the reflexology facilities in the garden and Figure 4 (c) shows the physiotherapy facilities in the garden. The facilities would provide opportunities for movement and exercises. Figure 4 (d) shows that there is a little Surau provided beside the garden. The Surau would be convenient to Muslim users whose punctually in praying is important while they are in the garden.

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(a)

(b)

Figure 5: (a) View beyond the garden; (b) Lacking of benches in the garden

(a)

(b)

(c)

(d)

Figure 6: (a) View playground; (b) Sitting area in the playground; (c) Waiting area beside of the playground; (d) Public phone facilities near to the playground.

Figure 5 (a) shows that the garden is located near to the main road (please refer to schematic plan). The main road beyond the garden is North-South Expressway (PLUS) which would cause heavy traffic and noise. This might cause discomfort and disturbance to the users in fact might harm their health. Figure 5 (b) shows there are lack of benches in the garden; users might not have enough space to sit and rest when in the garden. The location of the therapeutic garden is strategically located for the hospital in the sense that it acts as a buffer zone from the noise of the heavy traffic to the hospital interiors.

There are playground facilities provided in the hospital and is located opposite the therapeutic the garden as shows in Figure 6 (a). Even thought it is not included as part of the garden but the researcher felt that it is relevant to the garden element as it provided opportunities for movement and exercises especially for children. At the same time, it also provides area for children to play when they felt bored waiting in the treatment rooms or the wards. Figure 6 (b) shows the sitting area in the playground for parents to sit and rest whiles their children playing at the playground.

Besides, waiting area is also provided beside of the playground as shown in Figure 6 (c) as alternative place to stay if sitting area in playground is full. Besides, since the playground is located *Corresponding author (Fuziah Ibrahim). Tel/Fax: +60-4-6532834. E-mail address: fuziah@usm.my.

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beside of the orthopedic clinic, patients prefer to be in the outside waiting area rather than staying in the clinic while waiting to receive treatment. Figure 6 (d) shows the public phone service is provided near to playground.

Figure 7: The schematic plan of the healing garden in Hospital Kepala Batas 3.1 Observation at Hospital Kepala Batas, Pulau Pinang The second observation site is the Hospital Kepala Batas, Pulau Pinang. Hospital Kepala Batas is located at Seberang Perai Utara district in Penang state and is operated since January 2003. It was built to give services to people in Seberang Perai Utara district and to served over two hundred and ninety thousand people from the district. In fact, Kepala Batas city is a new emerging develop district for Seberang Perai Utara. Kepala Batas is planned to move towards â&#x20AC;&#x153;Medical Cityâ&#x20AC;? in the future and Hospital Kepala Batas plays an important role in the planning deveoplment. (Portal Rasmi Hospital Kepala Batas, 2013).

The design of the garden in the Hospital Kepala Batas is different with Hospital Seberang Jaya as it is designed with the courtyard within the hospital building as shows in Figure 8 (a). The garden fully utilize all spaces and is compacted in the courtyard (please refer to the schematic plan). Figure 8 (b), (c) and (d) shows the main entrance of the garden, the mixture of hard and soft landscape provides a pleasing and comfortable environment. Besides the main entrance it could be 290

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accessed from four other entrances. Tall trees which provided the needed shade are mixed well with herbal shrubs which enhances the space with colorful flowers, and sweet smelling Jasmine and other herbal flowers.

(a)

(b)

(c)

(d)

Figure 8: (a) Location of the garden; (b-c) Main entrance of the garden; (d) Garden appearance

(a)

(b)

(c)

(d)

Figure 9: (a-b) Water element in the garden; (c-d) Pathway design in the garden.

Figure 9 (a) and (b) shows two different designed water fountains in the garden. The sound of water would provide calming down and soothing effect to the users. Figure 9 (c) and (d) shows the pathway design in the garden. Although the pathway arrangements were too narrow and was not accessible for wheelchair users hence discouraging the wheelchair users, it was pleasant enough for other users to walk through the garden. The observation reveals that some patrons used the garden as a way to get to other parts of the building.

Figure 10 (a) shows the design of covered pathway in the garden. The covered pathway provided shading and users are not exposed to the sunlight and would stayed in the garden for longer period. Figure 10 (b) shows the sitting area in the garden. The sitting area is fully covered by the atap roofing material, hence users might free from exposure to sunlight and raining. Figure 10 (c) shows that people used the pathway in the garden as a short cut. The observation, shows that many people preferred to use the garden as a short cut to across to another place rather than using corridor. *Corresponding author (Fuziah Ibrahim). Tel/Fax: +60-4-6532834. E-mail address: fuziah@usm.my.

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(a)

(b)

(c)

Figure 10: (a) Design of roof in the garden; (b) Sitting area in the garden; (c) User pass by the garden

(a) (b) Figure 11: (a-b) Pavilion in the garden.

(a)

(b)

(c)

(d)

(e) (f) Figure 12: (a) Therapeutic garden in the hospital; (b) The function of the therapeutic garden; (c-f) The pathway design of the therapeutic garden.

There is only one pavilion in the garden as shows in Figure 11 (a) and (b). The small number of the pavilion would limit the amount of user. Figure 11 (a) and (b) shows that people used the pavilion for relaxing and having their meals. Interviewed conducted revealed that the pavilion is also used as a praying space by some Muslim patrons especially male Muslims.

Figure 12 (a) shows the label of the Therapeutic Garden. The garden is also used for 292

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reflexology as there is a reflexology pathway provided and shows in Figure (b). Figure 12 (c), (d), (e) and (f) shows the pathway design in the therapeutic garden with different tactile pathway. As the function is limited for reflexology, patient with leg injuries might be discouraged to use the garden.

(a) (b) Figure 13: (a-b) Route appearance at entrance Figure 13 (a) and (b) shows the route at the garden entrance. The step from the corridor to the garden is too high and might be dangerous to the users. The users need to alert while walking to the garden.

4. Summary of Discussion Table 1 shows the comparison of the finding of the elements of garden from Hospital Seberang Jaya and Hospital Kepala Batas with Roger Ulrichâ&#x20AC;&#x2122;s Theory of Supportive Garden Design (Ulrich, 1999). The overall design from each hospital met the requirement state in Roger Ulrichâ&#x20AC;&#x2122;s Theory.

In term of visibility, some user might not be aware there is a therapeutic garden in the Hospital Seberang Jaya as the location is located in front of hospital main door and is less strategic because most people are using side door to enter the hospital building. Comparatively, the location of the therapeutic garden in Hospital Kepala Batas is more visible due to its strategic location in the centre of the building. It is a nice calm retreat for all patrons, since it is located beside the pharmacy section. All out patients will go to the pharmacy to get their medications will not miss to see the garden and will eventually venture into it while waiting for their medications.

In term of accessibility, the therapeutic garden in Hospital Seberang Jaya could be accessible to all users, inclusive of wheelchair bound patients. The therapeutic garden in Hospital Kepala Batas is not accessible to wheelchair users because the paving of the pathway in the garden is too narrow for the wheelchairs. *Corresponding author (Fuziah Ibrahim). Tel/Fax: +60-4-6532834. E-mail address: fuziah@usm.my.

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Table 1: Comparison of the finding of the elements of garden from Hospital Seberang Jaya and Hospital Kepala Batas with Roger Ulrich’s Theory of Supportive Garden Design (Ulrich, 1999).

Element of Gardens from Roger Ulrich’s Theory of Hospital Seberang Hospital Kepala Supportive Garden Design (Ulrich 1999) Jaya Batas To provide opportunities for movement and exercise * * To provide opportunities to make choices, seek privacy * * To encourage people gather together and experience social support To encourage positive distractions with nature * * Visibility * Accessibility * Familiarity * * Quiet * Comfort * Unambiguously positive art * * Due to the location of the garden in Hospital Seberang Jaya, is quite noisy from the traffic of the North-South Expressway (PLUS), which is located in front of the hospital. In contrast, the patrons in Hospital Kepala Batas could really enjoyed the quietness of the garden since the location is in a form of courtyard in the hospital. The “noise” that the patrons could hear is the sound of the water fountain and sometimes the chipping sound of birds.

In term of comfort, patrons in Hospital Seberang Jaya would felt less comfortable compared with Hospital Kepala Batas due to less number of benches in the garden. The only sitting area in the garden is the three pavilions and patrons might not have enough sitting place when all the pavilions were fully occupied. However there are plenty of benches around the hospital compound itself.

Patrons in Hospital Kepala Batas would enjoyed more comfortable environment in the garden even though there is only one pavilion and one sitting area in the garden. The garden is located at the courtyard of the building and patrons might sit on the benches located at the corridor or in front of the pharmacy clinic.

Both the gardens do not actually have the element that would encourage people to gather together and experience social support. Both the gardens are meant for seclusion, resting and relaxing. Both the gardens also do have any unambiguously positive art. It is in accordance to Ulrich, et al(1999) as inappropriate sculptural abstract figures of birds in courtyard cause dislike and fear emotion by cancer patients in adjacent wards and had been removed in their respective hospitals.

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Beside the observation, informal interviews were conducted to identify level of the userâ&#x20AC;&#x2122;s satisfaction on the current garden condition.

Among the patrons, the major reason of them attending the hospital are for visiting family member or friends and others receiving treatment. Patrons went to the garden are to accompany their children to playground and waiting for relatives to receiving treatment. Some of them went to the garden for relaxation, having some quiet moments and even to do a bit of light stretching and excises.

On their satisfactory level to the current garden condition, for Hospital Seberang Jaya most of them are not satisfied due to the poor maintenance of playground and the cleanliness issues.

Patrons comment about not well maintained playground would be dangerous or even cause injury to the children. The grass in the garden is not well maintained and the cleanliness on the chairs and tables are not at acceptable level. There are areas in the garden that are quite hot in the afternoon that the patron refused to choose as substitute location to the clinic. However the garden in Hospital Kepala Batas is well maintained as approved by the patrons.

Since this study is conducted as a preliminary study to a prospective cohort study, the interviews were only conducted from the convenient samplings from the patrons who visited the garden. On the continuation of the study, further interview will be carried out to the staff of the healthcare facilities to reveal if they actually use the garden to calm down from their stressful work load. More healthcare facilities will be looked into especially those who claimed to have therapeutic gardens as well as healthcare facilities which do not have any therapeutic gardens.

5. Conclusion The study reveals that both the gardens met most of the requirement state by Roger Ulrichâ&#x20AC;&#x2122;s Theory of Supportive Garden Design, even though their design are different from each other. They have all the features of visibility, encouraging positive distraction with nature, easily accessible to most patrons, seeking some privacy from the crowded waiting areas in the hospital, some positive arts for relaxing the eyes.

The study reveals the patrons would chose to go to garden as their substitute location before or *Corresponding author (Fuziah Ibrahim). Tel/Fax: +60-4-6532834. E-mail address: fuziah@usm.my.

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while waiting for a treatment. The garden is a relief to the children who are getting easily bored while in hospital building. This exploratory study also shows that the playground for children and waiting space was the main demand among others and it should be taken as primary consideration in garden design. This finding suits to Ulrich (1999) as quoted in the Roger Ulrich’s Theory of Supportive Garden Design that the garden would provide opportunities for movement and exercise, to encourage positive distractions with nature and comfortable environment for users.

Garden with playground provided opportunities for movement and exercise, and comfortable environment lets users waiting their relatives in comfortable situation. The current condition in the garden is upgradable and the interactivity among users is expandable.

Hence, based on the findings in this preliminary study, playground and comfortable waiting space would be the added elements in the healing garden.

6. Acknowledgements The authors would like to thank reviewers who gave guidance and comment leading our article to higher efficient and quality.

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Ooi Say Jer is a postgraduate student from School of Housing, Building and Planning in Universiti Sains Malaysia, Malaysia. He is pursuing his MSc. (Interior Design) program in research. His research work encompasses healing garden.

Dr. Fuziah Ibrahim is an Associate Professor in School of Housing, Building and Planning from Universiti Sains Malaysia, Malaysia. She is a lecturer in the Architectural Programme. Her Ph.D. is from Manchester Metropolitan University (1995), M.A. (Industrial Design) from Manchester Polytechnic (1991) and Hons. (HBP) from USM. She received a letter of commendation from the Head of Department for her research achievements carried out for her M.A. dissertation. Dr. Fuziah's specializes in product design and development and interior design.

Peer Review: This article has been internationally peer-reviewed and accepted for publication according to the guidelines given at the journal’s website.

Note: Original version of this article was accepted and presented at the International Workshop on Livable Cities (IWLC2013) – a joint conference with International Conference on Sustainable Architecture and Urban Design (ICSAUD2013) organized by the Centre of Research Initiatives and School of Housing, Building & Planning, Universiti Sains Malaysia, Penang, Malaysia from October 2rd to 5th, 2013.

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