Research On Coordinated Regenerative Braking Control Algorithm Based On Decoupling Brake By Wire System

In recent years,new energy vehicles have been vigorously promoted,and the biggest obstacle in the development of new energy vehicles is the driving range problem.To solve the problem,we need to start from many aspects.Regenerative braking is the only choice to solve this problem,and regenerative braking is bound to change the original braking force distribution characteristics and braking performance of vehicles,Many enterprise researchers have carried out relevant research on regenerative braking control.Because coordinated regenerative braking can achieve high energy recovery rate,the current mainstream research direction of regenerative braking is coordinated regenerative braking,and coordinated regenerative braking needs to redistribute the braking force and take into account multiple performance indicators.In this paper,based on the fully decoupled brake by wire system,the coordinated regenerative braking is studied,which can achieve high energy recovery rate and ensure the safety and comfort of braking.Firstly,the mathematical model of each component of the system is established,and then the simulation model is built in Matlab/Simulink,Secondly,the regenerative braking control strategy and the executive layer control strategy are designed.Finally,the joint simulation and hardware in the loop experiment are carried out.The details are as follows:(1)Modeling of brake by wire system and regenerative braking system.Firstly,the system composition of this paper is briefly described,including brake-by-wire system(including Ebooster,brake master cylinder,brake wheel cylinder,HCU and pressure sensor)and regenerative braking system(including front and rear driving motors).Secondly,the mathematical models of Ebooster motor and driving motor,Ebooster transmission mechanism,brake master cylinder,wheel cylinder,HCU and battery are established,and the corresponding simulation models are built based on the mathematical models.Finally,the above-mentioned brake master cylinder(2)Design regenerative braking control strategy.Firstly,the hierarchical controller architecture of this paper is briefly described;secondly,various influencing factors of regenerative braking are analyzed;and then the regenerative braking algorithm architecture studied in this paper is briefly described;finally,the regenerative braking control algorithm is designed based on the calculation method of maximum regenerative braking force,braking force distribution theory and model predictive control theory.(3)Design the executive control strategy.Firstly,the control method of permanent magnet synchronous motor is briefly introduced.Secondly,the control algorithm of Ebooster motor is designed,and the position loop,speed loop and current loop are simulated and verified.Finally,the control algorithm of driving motor is designed to complete the simulation verification of regenerative braking torque following control.Simulation results show that the motor control strategy designed in this paper has a good control effect.(4)Based on Matlab/Simulink and Carsim,the above control strategies(including regenerative braking control strategy and executive layer control strategy)are simulated jointly,including nine working conditions with different braking intensity and different vehicle speeds.The simulation results are analyzed,and the results prove that the control strategy designed in this paper meets the design objectives and has certain feasibility.Relying on the hardware resources of the research group,the control strategy proposed in this paper is verified by hardware-in-the-loop test,and its test conditions are consistent with the simulation.According to the final results,it can be considered that the strategy proposed in this paper can guarantee the safety,smoothness and energy recovery rate of braking.