Research On Economic Speed Planning Method For Electric Vehicles On Urban Roads

Electrification and connectivity offer great opportunities to further improve the energy economy of vehicles.Electrification has promoted changes in vehicle drive/brake system technology,electric driving technology improves the efficiency of the powertrain significantly,and regenerative braking technology improves the energy economy of vehicles greatly.Functions like vehicle-to-vehicle(V2V)communication and vehicle-toinfrastructure(V2I)communication are now available on vehicles,which are beneficial for vehicle path planning and speed planning.To further improve the energy economy of electric vehicles(EVs),this paper takes the front-axle-driven EVs as the object,compares the differences of economic driving strategies between EVs and internal combustion engine vehicles(ICEVs),and designs economic speed planning method of EVs in multiple signalized intersections under urban environment.At the same time,to evaluate energy-saving contributions brought by the speed planning method,the electric drive/brake system research platform is built.Firstly,software-in-the-loop and hardware-in-the-loop research platforms for the electric drive/brake system are built.The models and control strategies of both electric drive/brake system and hydraulic braking system are built in MATLAB/Simulink,the traffic scenarios are built in Car Maker.The hardware-in-the-loop test bench is built on d SPACE/SCALEXIO platform by combining the models,control strategies,the traffic scenarios and the real electric drive/brake system together.Then comparisons of economic driving strategies among electric vehicles with regenerative braking(REVs),EVs and ICEVs are made.The driving task model is established,which defines the boundary conditions and constraints of the problems.Taking the energy consumed in the task as the objective function,the economic speed planning optimal control problems for REVs,EVs and ICEVs are built.Then,the optimal control problems are solved by numerical software named GPOPS,which is developed based on the pseudospectral method.Conclusions are drawn based on the numerical solutions.After that,the economic speed planning method of REVs in multiple signalized intersections under urban environments is designed.The multiple signalized intersections model is built with reasonable assumptions.The target average speed intervals are calculated based on signal phase and timing(SPAT).The target speeds are achieved by prescribed acceleration and deceleration profile or multiple-phase knotting technology combining the pseudospectral method.To guarantee the speed tracking performance and energy economy,the speed controller is built based on model predictive control.Cosimulations based on MATLAB/Simulink and Car Maker software platform are carried out to verify the effectiveness of the speed planning and control method.Finally,the electric drive/brake system hardware-in-the-loop test is carried out,which verifies the basic functions of the test bench and evaluates the effectiveness of the speed planning and tracking method.