Research And Design Of Road Traffic Flow Detection System Based Inductive Loop

Intelligent Transportation Systems (ITS) is a new highway traffic system, which is the trinity of personnel, vehicles and road, using sophisticated electronic information technology. ITS is a kind of systems combined with the advanced computer technology, information technology, data-communication technique, auto-control art, artificial intelligence and electronic technology, etc. It has been applied in traffic-transportation management system, helps to establish a wide-extent, whole-direction, accurate, punctual, efficient traffic-transportation management system. ITS is material representation that modern science and technology means applies for traffic field, that apply itself to abates air-logged road and reduce traffic accident, increase road user's convenience and comfort, representing intending roadway and traffic developmental orientation.In this thesis, the traffic flow detection system is emphatically studies. It is the most basic and the most important part of traffic flow detection system. A road traffic flow detection system based on induction coil is designed. The control platform based on the most advanced 32-bit ARM processor core LPC2138 as central hardware is constructed, together with CPLD. Subsequently, the traffic flow detection system respectively based on dual-coil and single coil are designed. By combination of laboratory simulation and field experiments, the design defect such as the traditional treatment capacity deficiency, low measurement accuracy and weak anti-interference ability, etc, is overcome. The data of the frequency change caused by the vehicles through the coil will be collected. Then according the obvious different characteristics of the output curve, the vehicle classification can be put forward.On the basis of theoretical study and simulation experiment, the theory of loop-coil detect is described.And the feasibility of this theory is further verified by actual measurement. The time of the vehicle through the coil is short, which requires the system can be able to quickly and accurately measure the vehicle information. So ARM7 series MCU is adopted in this system as processing unit. Compared with traditional SCM detection and control, this control unit has the features of strong information processing ability, fast speed, good communications and high storage capacity, etc. It provides reliable guarantee for the system's rapid acquisition information。In accordance with system requirements, the hardware structure frame of vehicle detection system based on inductive loop is designed, and specific hardware implementation of the control unit of the coil detection system with the LPC2138 as the core is introduced. The software design procedure is expounded in detail. The main functions of hardware modules are briefly analyzed. And the anti-interference measures in the design of hardware and software are explained. Compared with other detection products using traditional frequency measurement technology, the stability of the system operating in Poor working environment is enhanced, and detection accuracy is improved significantly. Finally, the further research is forecasted.The development of the loop coil detection system based on ARM7 series and the information obtained by field experiments provides a new means and new ideas for the research of Intelligent Transportation System in the traffic flow detection. The system not only have improved the system's detection precision and anti interference performances, and have overcome the disadvantages of the past loop coil detection system, but also have provided much reliable basis for the next step to apply the detection system to the practice.