Cooperative Optimization Of Traffic Signal And Vehicle Ttrajectory At Intersection

Intersection with signal is a common scene in urban traffic environment,and massive vehicle congestion happen easily at intersection.The traditional constant phase time control method at intersection will cause delay by stop and wait of massive vehicles on the one hand,and on the other hand,additional fuel consumption will be caused by vehicles’ frequency stop-and-go and idling due to red lights.The development of intelligent transportation and intelligent connected vehicles gives a new approach to solve the congestion problem at intersection.In this dissertation,method of cooperative optimization of signal phase and vehicle trajectory at intersection is studied.Firstly,the application of signal phase at intersection is analyzed,and based on the analysis,the traffic simulation platform VISSIM is secondary developed through MATLAB and build a simulation environment for cooperative optimization of signal phase and vehicle trajectory.Basing on DP,the optimization method for two-phase signal timing at intersection with the minimum overall delay of vehicles in the road as the optimization objective is proposed,and the optimization algorithm is applied to the simulation environment as the basis of vehicle trajectory control.Secondly,the longitudinal kinematic model of the vehicle on a single lane is established,the distance from the vehicle to the intersection and the optimized signal phase are used as constraints to make the vehicle reach the intersection at the beginning of the green light to achieve barrier-free cross,at the same time,the minimum acceleration duration within the time constraint is obtained as the optimization objective to optimize fuel consumption,and the objective function is solved by using minimum principle of optimal control to obtain control strategies for vehicles with different initial states.At the same time,to take the characteristic of heavy traffic flow at the intersection scenario into consideration,a method to divide the vehicle platoon in the lane is proposed,the platoon is divided into the leading vehicle and the following vehicle,in which,the trajectory of leading vehicle is optimized through the fuel-optimal control principle,and the following vehicle will follow the preceding vehicle according to the constraints in the following model,so the platoon could be controllable.Finally,the simulation of the cooperative optimization method is carried out,and the overall delay is analyzed between original and optimization,meanwhile,an instantaneous fuel consumption model is used to calculate the fuel consumption in the simulation process,and the result show the validity of the cooperative optimization method.In the verification section,an intelligent car platoon is built by STM32 microcontroller to verify the validity of following model under multi-vehicle cooperative control environment,and after collected data from the running of system is fitted,the operation result is analyzed.