RFID Based Autonomous Mobile Vehicle

Transcription

1 RFID Based Autonomous Mobile Vehicle M. Jayashree Oli, T. Chetan Sai Kumar & K. Akshitha Electronics and Communication Engineering, Amrita vishwa vidyapeetam Bangalore, India Abstract Radio Frequency Identification (RFID) system is looked upon as one of the top ten important technologies in the 20th century. Industrial automation application is one of the key issues in developing RFID. Therefore, this paper designs and implements a RFID-based autonomous mobile vehicle for more extensively application of RFID systems. The microcontroller of ATmega 16 is used to control the autonomous mobile vehicle and to communicate with RFID reader. By storing the moving control commands such as turn right, turn left, speed up and speed down etc. into the RFID tags beforehand and sticking the tags on the tracks, the autonomous mobile vehicle can then read the moving control commands from the tags and accomplish the proper actions. Due to the convenience and non-contact characteristic of RFID systems, the proposed mobile car has great potential to be used for industrial automation, goods transportation, data transmission, and unmanned medical nursing etc. in the future. Experimental results demonstrate the validity of the proposed mobile vehicle. Keywords Radio Frequency Identification, Industrial Automation, Autonomous Mobile vehicle, RFID Reader, RFID Tag I. INTRODUCTION Radio Frequency Identification (RFID) system is looked upon as one of the top ten important technologies in the 20th century. According to the investigation of the AMR Research, the willingness for using RFID tags exceeds 85% based on 500 USA enterprises. Over twothirds of the investigated enterprises are being on the stage of planning, implementing, evaluating, and utilizing of RFID systems. According to the investigation, RFID is likely to become the main stream of the market in foreseeing years. Forrester predicted that there will be over 400 billion commodities labeled with RFID tags before The report of IDC published in 2004 shown that, the retailed providing chain of USA, due to much more involving and sophisticated, the market scale of RFID rapidly increases from USD 9.1 billion in 2003 to USD 130 billion in Thus, peoples call it the second IT revolution to describe the potential and development of RFID technology. The derived commercial opportunity is uncountable and boundless. In the upcoming years, the emphasis of RFID development should be put on the fields such as, the leading applications in public areas, the participation of RFID standards community, the construction of core technology, the education and training of R&D workforces, the development of new products, and the set-up of the basic research energy, etc RFID system is composed of two main parts: electronic tag and reader. According to the energized ways of tags, there are three categories of RFID, the active type, passive type, and half-active type, respectively. An active tag uses its internal power source to supply energy without the need of acquiring power from RFID reader to initialize. Since it can actively transmit signal, the identifiable distance can reach as far as some ten meters, and one hundred meters even more. Whereas, the limited life cycle and the higher cost are its disadvantages. Passive tag is not equipped with independent power and employs the electromagnetic energy transmitted by RFID reader to initialize its functions. It possesses the features of light weight, small size, long life, as well as low cost. The expiry date of passive tag is indefinite, thus meeting the requirements of the applications needing frequent and repeated writing/reading and being suitable for permanent data storage. The major drawback of passive type is, of course, the short identifiable distance. The applications of RFID systems include apparatus management, procedure control, personnel access control, electronic money pocket, electronic toll collection system, smart card, and industrial automation and so on. Undoubtedly, industrial automation application is one of the key issues in developing RFID. The utilization of RFID technology is novel and might enhance the existed automation system. A RFID-based autonomous mobile vehicle is designed and implemented in this paper for more extensively application of RFID systems. The microcontroller of ATmega 16 is used to control the proposed autonomous mobile vehicle and to communicate with RFID reader. Due to the uniqueness of RFID tag, the moving control 131

2 commands such as turn right, turn left, speed up and speed down etc. can be written into the RFID tags beforehand and the tags are then stuck on the tracks. The autonomous mobile vehicle can read the moving control commands from the tags and accomplish the proper actions. With this novel usage of RFID in industrial automation may, expectedly, lead to the wide and farreaching adoption of every area. Experimental results demonstrate the validity of the proposed system. II. SYSTEM ARCHITECHTURE Fig. 1 shows the hardware architecture of the proposed autonomous mobile car. The proposed car can be divided into four parts. 1) The RFID tags stuck on the tracks; 2) the RFID reader used to communicate with RFID tags and transmit the moving control commands to Micro Controllable Unit, (MCU) module; 3) the MCU module used to receive the moving control commands from RFID reader and control the mobile car; and 4) the mobile car. Passive RFID tags are used in this paper. The data transfer between passive RFID tag and RFID reader is shown in Fig. 2 and can be divided into the following four steps: 1) the RFID reader broadcasts electromagnetic signal to tag; 2) antenna in the tag receives the signal from the reader and stores charge in a capacitor; 3) when the capacitor has built up enough energy, it releases it over time to the tag's coils and 4) the tag s coils release an encoded radio wave containing the moving control commands in the tag, which the reader then demodulates. The 860 MHz ISO180006C mode tags and electronic reader are used in the experiments. The RFID tags in use possess (64 pages x 4 bytes) memory capacity. One tag can store the moving control commands of several cars; therefore, different vehicles can move in different paths according to moving control commands stored in and received from the tags. After the moving control commands were received by RFID reader, the commands will then be sent to MCU by USART. MCU will deal with those commands and control the mobile vehicle to turn left, turn right, speed up or speed down and so on through the I/O ports and Pulse Width Modulation (PWM). The MCU ATmega 16 features configurable unified 6k bytes internal RAM, I2C serial interface, UART, timers, programmable I/O ports, 8-bit Analog to Digital Conversion (ADC) and 16-bit high-resolution PWM etc; therefore, the MCU is suitable for industrial automation applications. Fig. 3 shows the concepts of the proposed autonomous mobile vehicle. From Fig. 3, it can be seen that the tags are stuck on the tracks and the car will move depending on the commands received from the tags. For example, while the vehicle moves to tag 1 and receives the commands of turn left and speeds up. Fig. 2: Data transfer between RFID reader and RFID tag Then the MCU will make some control actions to let the vehicle conform the commands. While the car moves to tag 2, the commands of go straight and slow down were received, the MCU will once again make some control actions to let the vehicle conform the commands. Therefore, the car will then move in moving path 1 automatically. Of course, the car can also move in the other paths according to the commands received from tags. Fig. 4 shows the physical hardware of the proposed RFID-based autonomous mobile vehicle. Fig. 1 : Hardware Architechture of proposed mobile vehicle Fig. 3 : Arena of RFID based Autonomous Mobile Vehicle 132

3 Fig. 4 : Physical architecture of proposed vehicle the motors according the commands received from the tags. Therefore, the main firmware programmed as shown in Fig. 5 can be divided into two parts; tag data processing procedure and motor control procedure. The flowchart of tag data processing procedure is shown in Fig. 6. From Fig. 6, it can be clearly observed that MCU will transmit the request command to tags and then received control commands from tags periodically. The control commands should include the moving forward/backward, direction and speed etc. If the commands have been received completely, the commands will be further transmitted from RFID reader to MCU. Fig. 7 shows the flowchart of motor control procedure. From Fig. 7, it can be seen that after the MCU received the control commands from RFID reader, the MCU will calculate and then send the PWM signals through the control signals to motors; and therefore, the vehicle will move according to the signals. III. FIRMWARE FOR THE PROPOSED VEHICLE Due to limited budget, a simple and cheap motor is used in the proposed autonomous mobile car. Of course, a high precise motor can also be integrated into the proposed vehicle to achieve more advanced and accurate control without modifying the architecture represented in this paper. Two motors are used in the proposed vehicle for direction and speed controls, respectively. The two control signals generated by MCU are used to control one motor. By changing the outputs of the MCU the vehicle can be turn left, right, backward or forward respectively. Fig. 6 : Flowchart of Tag data processing procedure Fig. 5: Flow chart of Firmware programmed for the proposed vehicle The firmware programmed in ATmega 16 is designed to communicate with RFID tags and control Fig. 7 : Flowchart of Motor Control Procedure 133

4 The RFID tags in use possess (64 pages x 4 bytes) memory capacity. The paper only employs 3 bytes to control moving path of one vehicle. Of course, more accurate control commands can also be planned; for example, more divisions for direction and speed control such as turn for 2 sec. left with speed 10 cm/s etc. can be planned and stored in tags to control the car. IV. EXPERIMENTAL RESULTS A RFID-based autonomous mobile vehicle was designed and implemented in this paper. Several moving paths have been planned and tested; however, only four cases are shown here. Four tags are used to control the vehicle with respect to the three cases, respectively. In the following fig 8, when a tag AK is near the as pre-defined the motor moves forward until it detects another tag it doesn t change its direction. The output is displayed on the LCD. In the following fig 10, When a tag MG is near to the reader its data is transferred and motor turns in right direction for some time and then it moves forward until it detects another tag it doesn t change its direction. Fig. 10: Display showing the right motion of the vehicle In the following fig 11, if a tag MA is near the as pre-defined the motor turns left and then moves forward until it detects another tag it doesn t change its direction. The output is displayed on the LCD. Fig. 8 : Display showing forward motion of vehicle In the fig 9, when a tag TC is in the vicinity of the as pre-defined the motor moves backward until it detects another tag it doesn t change its direction. Fig. 9 : Display showing the backward motion of the vehicle Fig. 11 : Display showing the Left motion of the vehicle The initial conditions for the car are moving forward in speed 30 cm/s. The control commands received from tags and the action performed by the motor is displayed on LCD as shown in Figs. 8, 9, 10 and 11 for the four test cases, respectively. All test cases as shown in Figures 8, 9, 10 and 11 shows that the proposed vehicle can move according to the control commands received from the tags. Therefore the validity of the proposed system can be demonstrated. V. CONCLUSION RFID system is looked upon as one of the top ten important technologies in the 20th century. Undoubtedly, the industrial automation application is one of the key issues in developing RFID. The 134

5 utilization of RFID technology is novel and might enhance the existed automation system. A RFID-based autonomous mobile vehicle was successfully designed and implemented in this paper. By writing the moving control commands into the RFID tags beforehand and sticking the tags on the tracks, the autonomous mobile vehicle can then read the moving commands from tags and accomplish the proper actions. Experimental results demonstrated the validity of the proposed system. Some more comprehensive and advanced control methods and their corresponding control commands can also be designed and stored in tags and then used to control the car accurately, the research will be investigated in the future. VI. REFERENCES [1] AMR research web site, [2] Forrester research inc., [3] Landt, J.; The history of RFID, IEEE Potentials, Volume 24, Issue 4, Oct.-Nov. 2005, pp [4] Weinstein, R.; RFID: a technical overview and its application to the enterprise, IT Professional, Volume 7, Issue 3, May-June 2005, pp [5] Bansal, R.; Coming soon to a Wal-Mart near you, IEEE Antennas and Propagation Magazine, Volume 45, Issue 6, Dec. 2003, pp [6] Perakslis, C.; Wolk, R.; Social acceptance of RFID as a biometric security method, IEEE Technology and Society Magazine, Vol. 25, Issue 3, 2006, pp [7] Special issue on RFID systems IEEE Transactions on Automation Science and Engineering, Vol. 4, Issue 1, Jan [8] Jabbar, H.; Taikyeong Jeong; Jun Hwang; Gyungleen Park; Viewer identification and authentication in IPTV using RFID technique, IEEE Transactions on Consumer Electronics, Vol. 54, Issue 1, February 2008, pp [9] Roussos, G.; Enabling RFID in retail, Computer, Volume 39, Issue 3, March 2006 pp [10] Dianmin Yue; Xiaodan Wu; Junbo Bai; RFID application framework for pharmaceutical supply chain, IEEE International Conference on Service Operations and Logistics, and Informatics, Vol. 1, Oct. 2008, pp [11] Rajparthiban, R.; Aravind, C.V.; Kannan; Development of an active RFID communicator for automatic control applications, 5 th International Colloquium on Signal Processing & Its Applications, March 2009, pp [12] Gandino, F.; Montrucchio, B.; Rebaudengo, M.; Sanchez, E.R.; On improving automation by integrating RFID in the traceability management of the Agri-food sector, IEEE Transactions on Industrial Electronics, Vol. 56, Issue 7, July 2009, pp [13] Floerkemeier, C.; Fleisch, E.; RFID applications: interfacing with readers, IEEE Software, Vol. 25, Issue 3, May-June 2008, pp [14] Shun-Yu Chan, Shang-Wen Luan, Jen-Hao Teng, Ming-Chang Tsai, Design and implementation of a RFID-based power meter and outage recording system, IEEE International Conference on Sustainable Energy Technologies, Singapore, 2008 [15] Roh, S.-g.; Choi, H.R.; 3-D tag-based RFID system for recognition of object, IEEE Transactions on Automation Science and Engineering, Vol. 6, Issue 1, Jan. 2009, pp [16] Sheng, Q.Z.; Xue Li; Zeadally, S.; Enabling next-generation RFID applications: solutions and challenges, Computer, Vol. 41, Issue 9, Sept. 2008, pp [17] Myungsik Kim; Nak Young Chong; Direction sensing RFID reader for mobile robot navigation, IEEE Transactions on Automation Science and Engineering, Vol. 6, Issue 1, Jan. 2009, pp [18] Microchip corporation, 135