Assist Research 2021 eTextile Excerpt

Creating the next generation of health wearables

2021 RESEARCH PORTFOLIO Energy Harvesting & Storage • Low Power Sensing Low Power Systems-on-Chip • E-Textiles • Engineered Systems

E-Textiles

Transformative Textiles Designs for SelfPowered, Multi-Modal Sensing Garments Objective:

Key Accomplishments:

The objective of this project is to apply macroscale strategies for innovative materials design and manufacturing to solve the tradeoff issues that exist between textile and device performance in the field of electronic textiles (e-textiles). The fundamental research explores mechanical burdens placed upon textiles by the incorporation of electronic materials and devices and the

Our team has determined a means for evaluating the impact of electrode location and contact pressure on the ECG sensing performance on the upper left arm. We also evaluated how the size of the armband form factor affects its ECG sensing performance. Our experimental results confirm that armbands exhibiting modeled contact pressures of 500 Pa to 1500 Pa can acquire ECG signals.

low cost means by which to resolve these burdens. Solutions sought through this effort primarily focus on commercially ready materials and processes, enabling rapid translation of

However, armband sizes exhibiting experimental contact pressures of 1297 ± 102 Pa demonstrated the best performance, with signal-to-noise ratios (SNR) comparable

the innovations to industry.

with wet electrode benchmarks. These results will be applied in an Institutional Review Board (IRB)-approved

Approach:

study with law enforcement in a local municipality (Town of Cary, NC). Our team is also creating an information portal

Our team is establishing garment design methods to validate the biometric performance of wearable systems.

Systematic studies are designed for testing the quality of ASSIST’s shirt and armband platforms, including a use case

for existing e-textile commercial products that incorporates teardown of the products to inspect materials and design trade-offs.

of law enforcement officer stress monitoring through biometrics analysis.

Impact: Biometric data quality of an e-textile smart garment is heavily reliant on the design strategy for fabrication of the garment and can vary from user to user. This project identifies the key factors in achieving design, comfort, and performance of smart textiles using methods that are manufacturable in the textile industry.

Arm sleeve test platform (left) and example comparison data (right) between ECG collected from the sleeve with Ag/AgCl dry electrodes and that obtained from the chest with Ag/AgCl wet electrodes.

Principal Investigators: Dr. Jesse Jur, Textile Engineering, Chemistry, & Science, NC State University Dr. Amanda Mills, Textile Engineering, Chemistry, & Science, NC State University

Students:

Funding source:

Tashana Flewwellin, Isabel Hines, Beomjun Ju, Furkan Kose, Braden Li, Marissa Noon, Busra Sennik, Olivia Turschak, Vince Varju 32

NSF ASSIST Center

Method of Automated Handling of Textiles for Improved Efficiency and Accuracy to Enable E-Textile Manufacturing Objective:

Key Accomplishments:

Automation through fabric handling and assembly is a necessary means for bringing textile manufacturing back to the United States. This method reduces the amount of labor necessary and enables new capabilities in textile product

We have successfully automated the grasping and transferring of the part pieces to construct an Improved Outer Tactical Vest (IOTV) cummerbund. Currently this product is being constructed manually with an average of

manufacturing to lower the end product cost. The cost issue is heightened for electronic textile products, lending to an

169 seconds spent just transferring the part pieces throughout the construction process for each production

increased need for automation. Currently, textile manufacturing is highly dependent on manual construction due to the challenges in automating the handling of fabric because of its flexibility and drape. Automated handling

batch. With the insertion of automated handling, this time can be reduced, and the process to construct the IOTV cummerbund can be streamlined.

can provide more reliable and consistent construction. The

Impact:

goal of this work is to use this automated handling technique to provide accurate placement of fabric, enabling new opportunities in e-textile product construction.

The implementation of automated handling in the construction of textile products will reduce the amount of labor required, allowing for shorter lead times as well as a more economically viable method for manufacturing domestically. Additionally, it will provide an avenue to integrate more advanced materials such as e-textile systems because of the improved consistency within the

Approach: We have developed an electromagnetic end-effector gripper that latches and connects to the rigid

construction from automated handling.

ferromagnetic components of the e-textile systems as a means for material handling. Instead of trying to grasp the fabric itself, we have developed a method of grasping either permanent or temporary connectors within the textile to handle and transfer different textile part pieces.

Automating the handling of the textile part pieces generates higher accuracy, consistency, and speed within construction of textile products, creating opportunities for advanced materials integration for applications such as wearable technology.

Electromagnetic end-effector gripper that latches and connects to the rigid ferromagnetic components of the e-textile system.

Principal Investigator: Dr. Jesse Jur, Textile Engineering, Chemistry, & Science, NC State University

Students:

Funding sources:

Zoë Rosenberg

UNC General Administration ARMY DEVCOM-CCDC

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Novel Textile-Based Sensors for Inner Prosthetic Socket Environment Monitoring Objective:

Impact:

This project aims to develop a novel Flexible InneR-socket Sensing Technology (FIRST) seamlessly, unobtrusively, and elegantly integrated into the lower-limb prosthesis socket.

FIRST is based on an electronic-fabric structure in which the fibers of the fabric act as sensory elements that can simultaneously track tactile forces, moisture/wetness,

Amputation is one of the major causes of disability. Sockets are the important prosthesis components and physical interface to integrate the prosthetic limbs mechanically with the amputee's residual limb to replace lost function.

Objective monitoring of the inner socket environment (i.e. pressure, temperature, and humidity) and residual muscle

electromyography and body temperature at multiple sensing points around the residual limb. The major challenge is to develop a fundamental understanding of the coupling and interaction between multi-component fiber crosssectional architecture, fabric structure, and its electro-

activity during daily prosthesis use requires flexible, unobtrusive, multi-modal sensors that can be integrated into the socket structure without causing subject discomfort. The lack of such an inner-socket sensor technology has been a long-standing problem for

mechanical response to achieve a multimodal sensor that can be unobtrusively integrated into 'textile-based' sensory

evaluating the prosthesis socket, preventing the complications elicited by poor socket design and fit, and

devices in general. The interpretation of the data is to identify locations of skin problems to enable patient selfmanagement and allow for more objective clinical

advancing the socket technologies. Therefore, advanced socket technologies are urgently needed and will be developed under this project to significantly reduce the

evaluation to avoid the occurrence of potential skin breakdown and the resulting complications.

number of clinic visits, lower healthcare costs for amputees, and ultimately improve their quality of life.

Approach: Our collaborative research team works on melt-extruded multi-component fiber and seam-line based sensor development in which we carefully engineer the fiber crosssection, fabric structure, and electrical response. This targets a sensitive and specific multimodal response using microfabricated and, ultimately, textile-based polymeric fibers with ordered segments of conducting and insulating areas in the fiber cross-sectional structure. We aim to unobtrusively integrate these into many electronic small- or large-area textile-based sensory devices and systems of the future, especially for health monitoring.

Key Accomplishments: We manufactured arrays of multi-component fiber and seam-line based sensors connected to a wireless highspeed data recording and transmission system via textile interconnects. We tested the sensors on an in vitro artificial limb testing setup and two in vivo experiments involving an able-bodied subject donning a bent-knee adapter and a bilateral transtibial amputee participant. In all these cases, the sensor array successfully detected pressure changes

Schematic depictions of the fiber and seam-line sensor arrays, images of the integrated textile sensors, and examples of integration and testing with human subjects, demonstrating successful detection of pressure changes.

within the inner socket during weight-shifting and walking experiments.

Principal Investigators: Dr. Alper Bozkurt, Electrical & Computer Engineering, NC State University Dr. Tushar Ghosh, Textile Engineering, Chemistry, & Science, NC State University Dr. Helen Huang, Biomedical Engineering, UNC-CH

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Student:

Funding source:

Brendan Thompson

NSF