Research On Coordinated Control Of Roll Stability And Braking Stability Performance Of Distributed Electric Vehicle

The distributed electric vehicle driven by hub motor will lead to the increase of mass center position and unsprung mass,which will affect the roll stability and braking coordinated control of the vehicle.In order to solve this problem,a distributed electric vehicle equipped with magnetorheological semi-active suspension and motor hydraulic compound braking is taken as the research object,the coordinated control of roll stability and braking stability of distributed electric vehicles is solved.The main contents are as follows:(1)For the single roll stability control,the lateral transfer of load is selected as the control objective.The model predictive control method is used to design the top roll stability controller to control the total anti roll torque generated by the semi-active suspension.At the same time,the suspension torque distributor is designed and the double line shifting condition is selected to simulate with the fishhook experiment,The experimental results show that the controller can improve the roll stability under extreme conditions,but slightly affect the yaw stability.(2)For the single control of braking stability,the braking stability under the normal condition and the extreme condition of additional yaw are studied.According to the i-curve,the front and rear axle braking distribution strategy and the compound braking strategy of the hydraulic motor under the normal working condition are formulated.The test results show that the control strategy meets the national standard;Based on the extreme condition of additional yaw moment,the control strategy of braking stability is studied.The MPC algorithm is used to design the yaw moment controller based on differential braking technology.The distribution relationship between yaw moment and wheel braking and torque is given,and the compound braking strategy of hydraulic motor under this condition is given,The simulation test of braking stability is carried out under the condition of low adhesion and double line shifting,and the braking torque distribution strategy of yaw moment controller is verified.The test results show that the sub control strategy can improve the braking stability under the extreme condition of additional yaw moment.(3)For the coordinated control of roll stability and braking stability of distributed electric vehicles,the lateral transfer of load and the steady value of yaw rate are taken as the control objectives.In order to ensure that the vehicle does not lose stability and rollover in the extreme condition,the model predictive control method is used to design the top roll stability and braking stability coordination controller to control the anti roll moment generated by the suspension and the anti yaw moment generated by the distributed electric vehicle.The front section design of the suspension torque distribution controller is used to distribute the total control roll torque,and the braking torque distributor is used to distribute the yaw torque.The double line shifting condition is selected and the fishhook experiment is carried out to verify the design of the controller.At the same time,the coordinated control and the single suspension control effect are compared,Compared with single suspension control,it has better performance in roll stability and braking stability.