Abstract: In order to improve the steering stability of four wheel motor driven vehicles when cornering at high speed,and accurately coordinate the differential control among the driving wheels,a differential steering control strategy based on driving torque distribution is designed. The strategy employs a layered control architecture. The upper controller calculates the total driving torque required by the vehicle based on sliding mode variable structure control algorithm and optimization of fuzzy global fast terminal sliding mode control for calculating additional yaw moment of vehicle differential steering based on improved particle swarm optimization algorithm. The lower controller optimizes the calculated total driving torque and additional yaw moment based on quadratic programming algorithm to obtain the driving torque of each wheel. Finally,the designed control strategy is verified by Carsim/Simulink software co-simulation,and the results show that compared to traditional control strategies, the differential steering control strategy can effectively reduce the peak response of the vehicle′s yaw rate and the side slip angle during high-speed cornering.

Key words: four wheel motor, differential steering control, improved particle swarm optimization algorithm, quadratic programming