Research On Public Transport Priority Method Based On V2X

Travel time predictive control is mostly used in the current bus priority control methods,but the effect of these methods is limited by the accuracy of travel time prediction.The accuracy of the travel time prediction is greatly affected by the environment,such as the deceleration of the preceding vehicle and the congestion of the vehicle.These factors will cause large errors in the travel time prediction and reduce the effect of bus priority control.For example,when the actual travel time is much longer than the predicted time,the bus will still not pass the intersection after the green light ends with the green extension control strategy.V2X is a new generation of Internet of Vehicles technology.The technology aims to improve traffic safety and traffic efficiency,through wireless communication between vehicle and vehicle(V2V),vehicle and infrastructure(V2I),vehicle and person(V2P),vehicle and external network(V2N).The advantages of V2 X technology are timely perception of the environmental conditions around the vehicle and 360° perception.And it is not easily affected by surrounding environment.Due to thses problems,this paper utilizes the characteristics of V2 X technology to study the public transportation priority control method based on V2 X.The specific research content is as follows:1.This paper designs a signal control system based on V2 X,deeply coupling the current advanced V2 X technology with the traditional signal control system.On the one hand,the control system can be compatible with the functions of traditional signal machines,and on the other hand,it can also perform V2 X communication,which make the control system to communicate with V2 X.The system includes V2 X core control module,main control module,drive module,yellow flash module,etc.Each module has a different role in the system.And the software and hardware of the system is designed.2.This paper designs a hardware-in-the-loop simulation platform based on SUMO.This platform concerns about the combination of V2 X technology and the bus priority communication system,as well as the interference between bus and non-bus vehicles.The simulation system includes SUMO software,Py Charm server,network switch,on-board display screen,on-board equipment,and traffic signal control system that is based on V2 X.SUMO is used to simulate the real road environment.Py Charm server platform can communicate with on-board equipment and traffic signal control system through TCP/IP,and also interacte with SUMO through the Tra CI module provided by SUMO.The network switch builds a local area network which is consisted of Py Charm,on-board equipment and OBU.The system is based on real map data,and can perform real-time data interaction,and feed back the execution results of the program to the simulation platform.The hardware-in-the-loop simulation platform ensures the actual execution effect of the program,while avoiding the drawbacks of road testing,greatly improving the efficiency of program development.3.The V2X-based bus detection technology is proposed.In the current bus priority system,coil detection system,GPS detection system,RFID radio frequency detection system and video detection system are mainly used in the bus detection methods.However,these methods have some problems,such as the short detection distance,the limited detection position by the installation position of the sensor,the inadequate detection information,the terrible real-time performance,and the poor interactivity.But the V2 X technology has the advantages of communication distance,interactivity,realtime,etc.At the same time,the V2 X wireless communication technology is not easily affected by the environment,such as weather,and it is360-degree perception and rich in interactive data.Due to the existing problems of the current bus priority system and the advantages of V2 X technology,a V2X-based bus priority scenario is designed.In this priority scenario,it consists of bus detection,virtual detection setting,and calculation of bus priority phase.4.A V2X-based dynamic feedback control method for bus priority is proposed.Due to the current bus priority control methods depend excessively on the prediction accuracy of bus travel time,this paper proposes a V2X-based dynamic feedback control method for public transport priority,basing on the characteristics of high real-time and good interaction of V2 X technology,combining the dynamic priority control method with vehicle speed guidance.The method consists of bus travel time prediction which is based on Kalman filtering,bus priority preliminary guidance scheme,dynamic signal control module and vehicle speed guidance module.This method could reduce the excessive dependence of the bus priority control strategy on the accuracy of bus travel time prediction and improve the anti-interference ability of bus priority control system.