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Position:IcFull.com » IC Electronic information » Category: R

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RFID-based Intelligent Traffic Control Design

In Electronic Infomation Category: R | on April 13,2011

1 Introduction

Order to alleviate the traffic pressure and SN74LVC32ADR datasheet and reduce the road capital investment, reduce vehicle delay, energy conservation, design of intelligent traffic control is to build resource-saving society, the inevitable choice. This paper presents a RFID-based intelligent traffic control, the use of RFID to detect the vehicle near the intersection, intelligent traffic control signals based on the collected vehicle information, select the appropriate intersection control mode adaptive control of the vehicle travel time, to ensure vehicle traffic quality.

2 intersection control mode

Intersection control mode is the traditional time control, road * pass signal delay time is fixed and SN74LVC32ADR price and can not adaptively according to traffic flow dynamic adjustment of delay time, resulting in long delays and SN74LVC32ADR suppliers and unnecessary traffic congestion, etc. situation. Junction can be controlled by the advanced control, green wave mode, night mode and the emergency stop mode. Fuzzy control model traffic flow based on random fuzzy intelligent completion time of change in traffic signal control. Green Wave with a model in one-way traffic all the roads of the peak of the time delay between the traffic lights start a certain amount of light to ensure all the way to navigate the vehicle. Night traffic flow control mode at night to use the state of zero load, use only the yellow light warning car drivers to reduce the consumption of energy and time. Emergency stop mode to open up access for emergency vehicles, space, open the green light in the direction of emergency vehicles, other direction turned red. The design put forward at different times using different control modes, at 9: 00 - 11: 30,14: 30 - 17: 30 and 20: 30 - 24: 00 time fuzzy control mode; at 5:30 - 9: 00,11: 30 - 14: 30 and 17: 30 - 20: 30 hours with green wave pattern; 0: 00 - 5: 30 time control mode by night; in the detection of an emergency vehicle with emergency stop control mode. Choose a variety of control mode can be achieved in the rationalization of traffic control, from the junction to ease traffic pressure in fact. Set specific time periods or according to specific regional traffic flow from the signal to reset or modified.

3 Intelligent Traffic Control Design

3. 1 intelligent traffic control signals are installed

3 .1 .1 signal hardware design:

Domestic signal is divided into two categories: the 8 / 16 bit microcontroller as the processor, features a simple, single solution, it is difficult to achieve regional coordination of traffic control, can not meet the requirements of modern traffic control; the other is based on IPC or PC104, features, while powerful, but because of IPC and PC104 are the standard by general-purpose computer design, not specifically designed for signal applications, hardware structure is complicated and costly. Signal abroad (such as the Siemens 2070 and the United States EAGLE) started early, high level, but not for mixed traffic pattern in China, and the price is costly and inconvenient. This selection is based on ARM-core 32-bit embedded processor S3C44B0X R ISC intelligent traffic signal hardware design, to achieve the traffic flow data acquisition and processing, communications, networking and regional coordination of the control design purpose, signal hardware structure shown in Figure 1 instructions.


Figure 1 signal hardware

Signal to be stored boot program, operating system and applications data, the system starts to run after the operating system and need more space, outside storage unit designed to extend the storage space, memory module includes 8MB of SDRAM, 2MB The NorFlash and 16MB of N andFlash. Memory used to store the time, phase and other parameters. Flow of traffic signals collected confidential information, traffic flow detection module consists of RFID tags, reader antennas and RF components. Design of RFID tag is TG200, RF reader to FR200. S3C44B0x not integrated network controller, so use NE2000 compatible RTL8019 Ethernet controller chip to extend the Ethernet. LCD display and keyboard module is used to manually set or modify the traffic signal control parameters. ZLG7290B extended by a 44 keyboard matrix, ZLG7290B IIC serial bus with the processor through the connection; S3C44B0X built-in LCD drive controller, LCD driver control can automatically generate the required control signals, so S3C44B0X direct connection with LCD, without the need to increase LCD controller. System is also designed power module, RTC (Real Time Clock) module. The design parameters of the input signal with the control, storage, control status output, light state output control, real-time detection and storage of traffic parameters, with programs stored in the time, countdown board control, Ethernet and communicate with handheld devices and other functions.

3 .1 .2 Signal Software Design

Signal parameters using interrupt receiving and distribution of traffic control instructions. Modern intelligent signal lights need to color the state simultaneously, with the countdown phase control, timing optimization, communications, and traffic inspection and other tasks. In order to solve the multi-tasking program structure brought about by the confusion, dysfunction, inefficiency and other issues, the introduction of the embedded operating system, uC linux to support multiple file systems, modular design and computer-based network communication. uC linux kernel to complete process management, memory management, file systems, device control and network implementation and other functions, the kernel is modular in design, many function blocks can be independently added or deleted, when the re-compile the kernel, select the required embedded devices function modules, remove the redundant modules. By reconfiguring the kernel, you can reduce the system needs to run the kernel, to reduce resource usage, thereby significantly reducing the hardware required to run the system resources.

Signal software from the system monitoring, traffic acquisition, intersection control mode selection, with the keypad scanner and LCD modules. The signal based on uC linux software structure shown in Figure 2.


software structure of Figure 2 Signal

3 .2 RFID technology-based vehicle detection

3 .2 .1 RFID-based vehicle detection program

RFID (Radio Frequency Ident ification) technology is a non-contact automatic identification technology that uses radio frequency signals and spatial coupling (inductive and electromagnetic coupling) transfer characteristics, RF card reader and wireless two-way communication between to realize the automatic identification of objects to be identified [8]. RF ID system consists of the basic reader, antenna, electronic label of three parts. Stored in the RFID tag using the unique ID identifies the object, high-speed reader automatically collect identifying information and data within the tag, enabling automatic identification of goods and information gathering capabilities logo items. Therefore, RFID technology can be of any moving objects in real time positioning, tracking and monitoring.

In the process of intelligent traffic control, signal confidential information based on real-time collection of vehicles to choose intersection control mode, the design is based on RF ID technology for vehicle detection. Such programs need to be demolished the existing traffic light device, simply paste the appropriate vehicle electronic tags, based on the original installation of traffic lights and adjust the lights RFID reader equipment controller software. Paste in the vehicle front windshield RFID tags, the traffic lights at the intersection of four directions the first 50 meters - 70 meters to install RFID readers, reader ramp on the road (extended reception range) to detect traffic flow near the intersection According to data collected by the vehicle, select the appropriate control mode and adjust the lights. When a phase of traffic flow than the other phase is large and the phase of the green light, then appropriate to extend the green phase of the cycle (green light green light cycle does not exceed the maximum period), to ensure that vehicles have sufficient time through the intersection; if the red phase light, red light is appropriate to shorten cycle (light cycle is not less than the minimum light cycle), to reduce vehicle waiting time, minimize the vehicle delay time at intersections.

Complicated as urban roads, it is easy to label cards diffraction reflection of microwave signals, to prevent the same RFID reader to read the card number by more than one, causing the vehicle to detect errors, through the software settings, once RFID card read signal, the follow-up reader in a specified time (eg 30 seconds) RFID card number on this screen, to avoid the same ID number is read in a card reader on the road after two false information sentence.

The vehicles RFID card ID number as a database key field. The vehicles ID number and license plate number of vehicle-related parameters associated with the database can be established, including model, engine number, chassis number, manufacture date, which examined the time limit, time limit to pay road maintenance fees and violation records; through the license plate number and vehicle owners correspondence between the owner can build a database of relevant information, including name, age, gender, unit, residence, and telephone (including fixed telephone and mobile phone) and so on. Established the basic parameters in the library, some for the operation of the vehicle, the vehicle also set some records parameters such as time and place of violation of fields; in the database has also established some of the graphics library, can record vehicle photos, pictures and vehicle owners illegal photos. The database also set the priority rights of vehicles, public transportation vehicles is set to normal priority, special vehicles (such as fire engines, ambulances, police cars) to the absolute priority. Once the tag detects the signal of special vehicles, the use of emergency stop control mode, the absolute green light to ensure the smooth passage of special vehicles.

3 .2 .2 RFID-based vehicle detection to achieve

This design uses active tags to identify vehicles TG200, FR200 multifunctional RFID reader to read RFID card information, TG200 and FR200 in the operating frequency is 433MH z, the maximum recognition distance of 150 meters, communication rate of 250Kbps, with low input costs, high reliability, high security, easy maintenance, installation and simple to implement. RFID reader via RS232 interface with S3C44B0x processor connected PC and the FR200 processor responsible for the completion of data transfer between the reader and control.

RFID data acquisition module includes: antenna, RF circuits and RF receiver circuit transmission, demodulation circuit, power supply, external communication interface, with its external communications interface to the final output of the RFID card ID information correctly. RFID data acquisition and processing flow chart shown in Figure 3. Vehicle file data (such as number, unit, priority rights, etc.) is stored in a unified file tx t file, process the data as a basis for identifying the data to determine the tag ID information is legitimate. If the tag ID information to judge NULL, then the alarm and other treatment; tag ID information if the judge as a special vehicle data, the priority control, data storage and so on. RFID information, acquisition time, location and other data are stored in a format * tx t file. Finally, the server terminal via Ethernet and Traffic Control Equipment to establish TCP / IP connection, intersection control devices will save files uploaded to the server for the management system. Upload file successfully deleted from the local F lash, the local Flash because of limited capacity, the use of round robin approach to storage, stored data exceeds 50MB, the store will be back at the beginning of the scope of coverage of the original file.


Figure 3 RFID data acquisition and processing flow chart

4 Conclusion

This paper proposes a RFID-based design of intelligent traffic control, at different times with different intersection control mode, based on uC linux S3C44B0X processor and operating system, development of intelligent traffic control signals, the use of active tags to identify TG200 vehicles, based on the traffic lights installed in the original multi-function RFID FR200 RFID card reader to read information from the terminal junctions of RFID reader, RFID collected data were processed to achieve the intelligent vehicle control.

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