Steering Stability Control of Four-wheel Hub Motor Driven Vehicle under Layered Control System

In order to eliminate the dangerous phenomenon that four-wheel hub motor driven electric vehicle is prone to instability when steering at high speed. This paper designs layered control control system which can control yaw stability to eliminate this problem. Layered control system is divided into three layers control structure. In the first layer control, two key parameters of vehicle steering stability were obtained by simplified vehicle model. In the second layer control, SMC is used to calculate the torque to maintain steering stability of the vehicle. In the third layer control, the optimal control method is adopted to properly allocate the torque of the four-wheel hub motor according to the torque from the second layer control. Finally, the layered control system is generated by Matlab/Simulink and the control system is applied to Carsim for simulation. As can be seen from the simulation figures, the layered control system proposed in this paper can effectively solve the problem of vehicle instability.