The Research On Curve Speed Warning System Based On Vehicle Infrastructure Cooperative Systems

Traffic accident on curves is a kind of traffic accidents,which has the characteristics of frequent occurrence,high probability of occurrence,harmfulness.According to the 2013 annual report of road traffic accident statistics,we can see that among that year the incidence of traffic accidents on curves up to 36 thousand,the number of deaths up to 14 thousand,accounted for 18.4% of the total number of road traffic accidents and 23.3%,respectively.More than 90% of the traffic accidents are caused by speeding and operating errors.Therefore,the research on the curve speed warning system based on road vehicle coordination had a great significance to reduce the traffic accident rate caused by speeding.This paper studies the road speed warning model based on Vehicle Infrastructure Cooperative Systems by the analysis of the domestic and foreign research status,and designs the warning system.Specific research contents are as follows:Firstly,modeling and analysis of vehicle safety speed on curves.This section analyzed the factors that affect the safety speed,considering the relationship between the dynamic stiffness of vehicle suspension and the angle of heel and the relationship between the vehicle overturning moment,the nonlinear change of tire and the wheel side slip angle.vehicle safety speed model is established based on Trucksim vehicle dynamics platform.Finally,the model of paper is compared with the traditional vehicle speed calculation model,LEE calculation model and Lussetti calculation model.Secondly,ZigBee wireless communication technology and acquisition of model parameters.Through the research and analysis of the technical characteristics and protocol architecture of ZigBee wireless short-range communication technology,the star network is selected as the most suitable for network topology.Then,the parameters that safety speed model on curves required is sent from roadside units to vehicle units by ZigBee wireless communication technology;Finally,the performance of the designed network was tested by OPNET simulation platform,which verifies the accuracy and real-time of the communication between nodes and nodes in the network.Thirdly,the hardware and software design of warning system.The hardware design of the early warning system is mainly about the design of the road side unit and the vehicle unit,According to the function of the warning system of the vehicle speed,the circuit diagram is drawn,the PCB board is designed and the device is welded.The software design is divided into two parts,one part is the code of the wireless communication by IAR EW development environment.After compiling without error,the program burned to the RF chip;another part is the code of the main control warning system unit by Code Warrior development environment.After compiling without error,the program burned to the system chip.Perform functional debuggingFinally,the simulation experiment of the vehicle speed warning system based on Vehicle Infrastructure Cooperative Systems.This part simulated experiments of the warning system in the Laboratory environment because of the risk of real vehicle experiment.The data of the road parameters and the safety status displayed by the screen in the course of the experiment.The results show that the speed warning system in this paper can accurately calculate the safety status of the current test curve,and has important practical significance to prevent traffic accidents.