Scientific Journal of Information Engineering February 2014, Volume 4, Issue 1, PP.8-12
Research and Application of Intelligent Control Technologies of Storage System Based on Radio Frequency Identification Zhiliang Zhu 1, 2, Qingsong Wang2#, Yangyi Wu2, Qiongjun Chen 2 1. College of Electrical & Information Engineering, Hunan University, Changsha Hunan 410082, China 2. College of Physic & Electronic Information Engineering, Wenzhou University, Wenzhou Zhejiang 325000, China #
Abstract Along with the industrialization development for the logistics storage requirements, the popularization and application of RFID identification technology in various fields, this paper mainly studies the RFID technology and its application involved in the control of the intelligent storage system, then puts forward a design of intelligent storage system based on RFID. Keyword: RFID; MIFARE; Intelligent Storage
1 INTRODUCTION Warehousing and logistics industry is an important area of net of thing (NOT) applications . The method widely used now is to combine the EPC network and wireless sensor networks (WSN) technology, and applied it to warehouse management, to build intelligent logistics warehouse management system, which based in the study of NOT and radio frequency identification (RFID) technology, aiming at aspects for the arising existing warehouse management problems. Intelligent logistics warehouse management system is now widely used in libraries, access control systems, food safety traceability and other industries, with the application of this technology, lower costs and improving service levels can be achieved, making management more convenient. RFID technology is a non-contact automatic identification technology; the basic principle is the use of RF signal coupling (electromagnetic induction or electromagnetic propagation) transmission characteristics, to achieve the automatic identification of objects. RFID tag reader and the RFID tag achieve radio communication through the antenna, including read or write operations of tag identification code and the memory data. It is a trend that RFID technology will be applied to the logistics industry, which can work without human intervention, and in a variety of harsh environments. RFID technology can also identify fast moving objects and multiple tags, whose process is quick and convenient.
2 DESIGN CONCEPT This system provides an intelligent storage system based on RFID device model, automaticly recognize target through the RF signal and access to relevant data, it can read and sample electronic tag data, control the motor by the MCU, put items into the specified location. So it well enables intelligent storage purposes and meets the development of intelligent storage.
3 HARDWARE DESIGN 3.1RFID technology The core of the entire hardware design is RFID module (read-write device), RFID is the connected bridge between goods and intelligent control center. Reading and writing device, generally consists of three parts, transponder, reader and application software systems; transponder is made up of antenna, the coupling components and chips; in general, tag are used as a transponder, each tag has a unique electronic code, which is attached to the object to -8http://www.sjie.org
identify the target object; reader is made up with the antenna, coupling components, chips, it can read and write tag information and be designed for handheld or fixed RFID reader; application software systems is the application layer software, mainly for further processing the collected data which used by people. How does RFID system work? The reader send a RF signal in specific frequency by the transmitting antenna, then the electronic tag will produce induced currents when the it reaches the effective work area, after its energy activated, send out itself encoded information through the built-in radio antenna; reader receives a modulated tag signal transmitted by antenna, after demodulated and decoded by the reader signal processing module, signal will be sent to the host system; host system can identify the tag according to the logic operation, makes corresponding processing and control according to different Settings, finally sends commands to control reader to complete different read and write operations. Figure 1 shows the communication between MCU to RC522 and MIFARE RC522
FIGURE 1 COMMUNICATION BETWEEN MCU TO RC522 AND MIFARE
When RC522 communicates with MCU, the MCU set RC522â€™s NSS pin low voltage, RC522 is written commands or data through the MOSI pin, MCU reads data from RC522 through the MISO pin. RC522 has two send ports, TX1 and TX2, which are used to transmit modulated energy carrier signal of 13.56 MHz, when tag (MIFARE card) reaches the scope of RC522 recognition, it will be activated. Receiving data by RX, tag completes the corresponding operations according to the received commands, then sends data by TX back to the RX of RC522, this is the process of reading data from label, which is similar to writing information process.
3.2 System components Execution agency Stepper motor Mechanical claw s
Drive circuit Servo
I / O
FIGURE 2 HARDWARE DESIGN WIREFRAMES
As shown above, the hardware components include the RC522 chip, MCU, stepper motors, servo, mechanical claws, drive circuit and others. 3.2.1 Read-write device Read-write device is mainly made up of RFID modules, including electronic tags, readers and antennas; Taking account to the actual application, high-frequency RFID is more suitable for this system model because it has higher data transmission speed and lower price, Read-write device is primarily used to obtain information about the goods and send the obtained information to MCU. 3.2.2 Control Center RC522 send the read data to the MCU which is the control center in serial mode, MCU make a determination based -9http://www.sjie.org
on the data received, control the stepper motor and the steering gear through the I/O output. The process is primarily finished by software. 3.2.3 Execution agency Stepper motor is one of the actuator that takes electrical pulse into the angular displacement . When the stepper drive receives a pulse signal, it will be drived to rotate a fixed angle in the set direction. The angular displacement can be controlled by controlling the number of pulses, so as to achieve accurate positioning purposes; At the same time, the motor rotation speed and acceleration can be controlled by the pulse frequency, so as to achieve the purpose of speed. By controlling the phase current direction of the drive signal and the number of pulses we can control the direction of stepper motor and the corresponding number of laps, send goods to the corresponding position, and the steering controlled mechanical claw to place goods when the goods reach the designated position. Hardware also includes positions and cargo transfer orbit.
4 SOFTWARE DESIGN Software mainly includes three-parts: reader, stepper motors and servos.
4.1 Reader software design Figure 3 shows the communication process between the MCU and RC522. MCU is the master device in SPI communication, firstly initialize RC522, then carry out specific operations on the RC522, different commands will lead different operations, MCU sends data and commands to RC522, and save those in FIFODataReg register.When commands are writted to the CommandReg register, the communication between RC522 and MIFARE card will be started. During the communication RC522 can read status register to determine the status, make corresponding control according to the state, finally returns the report whether the communication is success or not . Reading and w riting communication control register, set the communication parameters
Write commands and data to the FIFO buffer zone of RC522
Write command w ord to the command register of RC522,Start communicating w ith MIFARE card
Read Status Register, detect RC522 MIFARE card w ith The communication state, according to the state make a corresponding control
Finally return to the end of the communication status w ord,Instructs the communication success
FIGURE 3 MCU THE COMMUNICATION BETWEEN MCU WITH RC522 - 10 http://www.sjie.org
According to the control flow of data transferred between RC522 and MIFARE card, communication process may appear different states. The various states are subject to different treatment, which is the focus of reader software design. RC522 command set two basic commands (Tranceive and MFAuthent) that may be encountered during the execution of the communication status and treatment. These two commands are implemented to the MIFARE card to send/receive data and encrypted authentication. All operations on the MIFARE card can be completed through them, including the Request (look for cards), Anticollision (anti-collision ), Select (option card), READ (reader), WRITE (write cards), etc. The following is the specific implementation process of tranceive command. The RC522 FIFO data are readed firstly, after the baseband coding and digital carrier modulated the read data are sent to the MIFARE card via the communication interface by RF; then detect whether there are RF signal response from MIFARE card via the communication interface after transmission, finally the received signal is demodulate and decoded into the FIFO . We get the flowchart of an algorithm to process the command after analysising of these tranceive command executions. Send
Start RC522 timer
NO Send IDLE command，return error "Card no response"
YES Send IDLE command，return "Card is Successful"
Send IDLE command，returns the corresponding error w ord
YES Read CollReg value, determines the conflict position, send IDLE command
FIGURE 4 MIFARE CARD ALGORITHM FLOWCHART
Overall MIFARE card runs as this: firstly send request signal to detect whether RC522 MIFARE card is present in the range of sensing, then carry out anti-collision verify, select a card for communication when multiple cards exist, and finally next step is to read and write cards.
4.2 stepper motor software design - 11 http://www.sjie.org
The design idea of the stepper motor part of the software system   is to generate a certain frequency pulse signal, control the number of pulses, drive the stepper motor forward and reverse to take the goods to the specified positions. The pulse signal comes from the driving circuit controlled by MCU's I/O output.
4.3 Servo software design Servo control signal is a pulse width modulated signal , we can generate a certain frequency PWM wave to control the rotation angle of the rudder plate through the MCU's timer function; it is a linear relationship between pulse width and angle. By grasping the steering gear to control the opening and closing mechanism.
5 SUMMARY This system is an intelligent warehouse storage system model that combines radio frequency identification and embedded systems technology; completely express the architecture and operating principle of a simple intelligent storage system. Other than that, RFID technology will be well applied to the warehouse storage areas in this system; goods information can be read and classificatted automatically by this technology, so it can greatly reduce the labor involved, and the operation is simple, fast, efficient and convenient.
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Zhiliang Zhu, male, the Han nationality.
Qingsong Wang, male, the Han nationality,
He obtained his Bachelor degree in
Bachelor. He is majored in Electrical
Electrical Engineering and Automation
Engineering and Automation with Physical
from University of Electronic Science and
and Electronic Information Engineering
Technology of China (UESTC) in 2005;
Department of Wenzhou University. His
and Master in Signal and Information
research field is Internet of Things.
Telecommunications in 2008. Currently, being a lecture of Wenzhou University, he is pursuing his Ph. D degree in Hunan University, China. His research interest focuses on the field of intelligent robot control. Email: email@example.com
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