Optimization Of Vehicle Trajectory And Signal Timing At Signalized Intersections Based On Energy Consumption In CAV Environments

Vehicle braking and idling behaviors at intersections have led to a reduction in intersection operating efficiency and an increase in vehicle fuel consumption.With the development of intelligent network connection technology,real-time control of intersections can simultaneously consider the interaction of signal timing and vehicle trajectories to achieve realtime collaborative optimization,effectively reduce the fuel consumption of vehicles within the range of signalized intersections,and achieve eco-driving.In view of this,this paper proposes a coordinated optimization method of vehicle trajectory and signal timing at a plane intersection considering energy consumption in a CAV(Connected Autonomous Vehicles)environment,and the effect of the optimization is verified by simulation analysis.First,according to the optimal control theory,with the goal of minimizing vehicle fuel consumption,a CAV vehicle trajectory optimization model at an isolated intersection is constructed,and the numerical solution of vehicle trajectory is iteratively obtained based on the Pontryagin minimum principle.A MATLAB project was built to write a cross-contrast analysis of fuel consumption levels at intersections before and after CAV vehicle trajectory optimization under different initial speeds and traffic conditions.In the project,the average initial speed is divided into 3 cases: 15m/s,10m/s,and 5m/s;the traffic flow is divided into 4 cases: 450veh/h,600veh/h,750veh/h,and 900veh/h.The simulation results show that the trajectory optimization model can significantly reduce the fuel consumption at the intersection,and the trajectory optimization effect is better with the increase of the traffic flow and the decrease of the average initial speed.With a traffic flow of 900 veh/h and an average initial speed of 5 m/s,the reduced fuel consumption of the trajectory optimization is 23.29%.Secondly,in order to realize the coordinated optimization of CAV vehicle trajectory and signal timing,a two-level programming model is constructed where the top decision is optimized for intersection signal timing and the bottom decision is optimized for vehicle trajectory.Through simulation analysis,under the conditions of different initial speeds and traffic flows described above,the intersection fuel consumption level after only optimizing the vehicle trajectory and co-optimizing the vehicle trajectory and signal control was compared.The simulation results show that compared with the single trajectory optimization model,the fuel consumption level of vehicles passing through the intersection has been further reduced.Under the conditions of 900veh/h and initial speed of 5m/s,the average fuel consumption of vehicles at intersections after the collaborative optimization was reduced by 35.91%.Finally,under the mixed traffic flow conditions in which CAV vehicles and ordinary vehicles coexist,a coordinated optimization model of vehicle trajectory and signal control at the intersection is studied.Through simulation analysis,under the conditions of different CAV vehicle proportions and the above-mentioned initial speed and traffic conditions,the coordinated optimization effect of vehicle trajectory and signal control of mixed traffic flow is compared.The results show that as the proportion of CAV vehicles increases,the fuel consumption rate at intersections decreases significantly.When the traffic flow is 900 veh/h and the initial speed is 5 m/s,the corresponding intersection fuel consumption reduction rates are14.48%,33.09%,and 35.91 when the CAV ratios are 50%,70%,and 100%,respectively.