Design Of Dangerous Goods Vehicle Monitoring System In Highway Tunnel

China is one of the busiest countries for road transportation of dangerous goods.However,serious traffic accidents happen frequently highway in tunnel,especially those caused by dangerous goods vehicles.The traditional dangerous goods vehicle monitoring system based on GPS(Global Positioning System)and Beidou has two problems in tunnel: on the one hand,due to the shielding effect of the tunnel on the external electromagnetic wave,this kind of system can not receive external satellite signals,which makes it impossible to track the position and exchange information in the tunnel;on the other hand,this kind of system only focuses on the management of monitoring information,and lacks the reliability evaluation of dangerous goods vehicles from the perspective of the system model.Based on the above two points,the dangerous goods vehicle monitoring system in a highway tunnel has been designed.The contents mainly includes in the thesis:(1)The architecture of the dangerous goods vehicle monitoring system in highway tunnel is designed.The system includes a vehicle position monitoring subsystem and a vehicle status monitoring subsystem.The vehicle position monitoring subsystem uses tunnel positioning technology to monitor the position of dangerous goods vehicles.The vehicle status monitoring subsystem has two functions: one is to monitor the status of dangerous goods vehicles via CAN bus;the second is to use GO-Bayes method to evaluate the reliability of the dangerous goods vehicle brake system,and find out the fault part quickly through reverse reasoning.(2)Completed the research and improvement of the tunnel positioning algorithm and model.Two ranging methods,RSSI(Received Signal Strength Indication)ranging and TOA(Time of Arrival)ranging,are studied.The attenuation law of RSSI is analyzed,on this basis,an improved RSSI-d model is proposed to improve the accuracy of long-distance ranging.The TOA ranging method based on the Two-Way Time of Flight is analyzed,and verifies that the method can achieve high-precision ranging in the actual scene.The Least Square positioning algorithm with ranging error is studied,and the factors that affect the positioning accuracy of the Least Square positioning algorithm are analyzed by simulation.(3)Completed the modeling and reliability evaluation of the dangerous goods vehicle brake system.The working principle of the dangerous goods vehicle brake system is studied,the GO-Bayes modeling principle is studied.On this basis,the reliability evaluation model of dangerous goods vehicle brake system based on GO-Bayes is proposed.When brake system fails,the model can reverse infer the failure probability of the units in the system by Bayes formula,and the units with high failure probability should be inspected with emphasis.(4)Completed part of the software and hardware development work of the dangerous goods vehicle monitoring system.The dangerous goods vehicle position monitoring subsystem and the dangerous goods vehicle status monitoring subsystem based on CAN bus are built,the display interface of the dangerous goods vehicle position monitoring subsystem is developed,and the hardware circuit of the positioning module is designed.Finally,the function of the system is verified to realize the functions of position monitoring and status monitoring of dangerous goods vehicles.