Research On Detection Technology Of Vehicle Based On Single Loop-coil

Intelligent transportation system(ITS) from the global perspective of road traffic to build an efficient and real-time traffic management and transport systems, it combines the use of computer technology, sensor technology, communication technology and electronic control technology and other advanced technology to significantly improve the scientific level of the whole traffic management system. Intelligent transportation system improves the efficiency of transportation, abates traffic congestion, improves the capacity of road network, reduces traffic accidents and the environmental pollution based on existing traffic facilities. It is the most effective means to solve the traffic problem, and represents the developmental orientation of the roadway and traffic.This thesis studies emphatically on the traffic detector of intelligent transportation system. We designed the single loop detector based on the loop induction detector. Vehicle detector is the infrastructure in modern traffic control system that to measure speed, traffic flow, road occupancy and other basic data of vehicle, so as to provide basis for modeling, control and decision-inducing of intelligent transportation system. The single loop detector can avoid the problem of the mutual interference that traditional double loop detection has, and its circuit is simple, high reliability, low cost, especially for the fact that the existing road network has laid a large number of single loop detector, so this study has considerable economic value. However, the single loop detector can directly obtain traffic flow and road occupancy, but it can’t get speed of vehicle directly. This paper describes a method to achieve direct measurement of vehicle speed based on single loop-coil. The method is simple algorithm, high accuracy, to meet the requirements of intelligent transportation system.The letterpress establishes the theory model of single loop detector based on theoretical study, and proposes a new method to achieve direct measurement of the speed based on single loop-coil. In this method, the frequency data collected by single loop detector is transformed so that different types of vehicles in different situations through the loop coil have the same frequency variation with the standard curve, so as to make use of the upward slope of the frequency curve to measure vehicle speed, to achieve the single loop detector direct measurement of vehicle speed, and obtain the length of vehicle, vehicle flow and other traffic information.It spends a minor time for vehicles go across single loop, while the system should response fast and accurately, and be able to communicate with other devices. So, this system makes use of STM32F103ZET6 microprocessor with ARM-M3 kernel, which has high-powered process ability, communication ability and large storage space. In this paper, the design of hardware and software of the system was given.To further verify the effectiveness of the single loop detector for speed measurement of vehicle, we designed the speed test system based on infrared. The system is simple, easy to implement and high accuracy, to meet the requirements of speed measurement. This thesis describes the design of hardware and software of this system, and analyzes the measurement error, to verify the feasibility of the system for speed calibration. Experiments show that the method based on single loop-coil to achieve the speed measured directly proposed in this paper with high accuracy and robustness, it laid the foundation for single loop detector a wide range of practical applications.