Research Of Unsignalized Intersection Optimal Control Method In Intelligent Vehicle Infrastructure Cooperative Systems

Intelligent vehicle infrastructure cooperative systems (I-VICS) ensure traffic safety and improve efficiency by the real-time information interaction of on-board units, infrastructures and travelers. I-VICS is a hot topic in transportation at present, and also the future development direction of the intelligent transportation system. Intersection is the key area influencing the safety and efficiency of transportation system, and one of the most important issues in I-VICS research. Unsignalized intersection is a common intersection type, where drivers can not accurately predict the specific location and arrival time of the conflicted vehicles because of the narrow vision of the road or the fast speed of the vehicles, which lead to the high incidence of traffic accidents and low efficiency. Therefore, solving the safety and efficiency problem of the unsignalized intersetion has become an imminent transportation demand. Thus in this paper, unsignalized intersection optimal control methods was designed in I-VICS.First, paper designed an unsignalized intersection control system based on the technical features of I-VICS, gap acceptance theory of unsignalized intersection and "right of way" theory, developed information interaction strategy between vehicles and infrastructure, and defined basic unsignalized intersection control process.The paper designed two unsignalized intersection optimal control methods to adapt different traffic flows, which aimed at improving intersection efficiency and ensuring vehicle safety.(1) Designed an unsignalized optimal control method based on speed guidance which adapted to the large traffic flow. The method retains the consideration of the traditional signal control using phase to ensure the vehicles safety, and uses the speed guidance model and intersection optimal control model to optimize the virtual signal timing, converts it into the information of right of way and speed guidance and sends to vehicles. Experiments showed that this method can not only solve the signalized intersection "dilemma zone" problem, but alse improve the traffic efficiency under the premise of ensure vehicles safety.(2) Designed an unsignalized optimal control method based on timed Petri net which adapted to the small traffic flow. The method try to make the intersection transportation resources are utilized to the maximum, so that the vehicle can through the intersection according to their arrival time. The unsignalized intersection was modeled by timed Petri net. A target function of intersection vehicle most quickly dissipated was established and using recursion to solve the vehicles optimum sequence crossing the intersection. Experiments proved that the method can ensure the safety and traffic efficiency in small traffic flow.Paper used reserved interface of the I-VICS simulation platform designed an unsignalized intersection control federation based on HLA. The federation is designed with the functions of data receiving, processing, method implementation and result statistical, which provided a powerful platform for validation test. On the simulation platform, it was proved that the two designed unsignalized control method is effective and fulfill the expected requirements.