Abstract: Firstly, the dynamics model for an eight-axle distributed electric drive vehicle is established, and a two-layer control strategy for differential steering based on centroid sideslip angle is proposed. The upper controller takes the centroid sideslip angle and its change rate and the turning angle of front wheel as inputs, and adopts fuzzy control to generate the relative positions of the steering centers of mechanical steering axle and differential steering axle, to obtain the reference steering angle of rear axle. The lower controller takes the reference steering angle in upper controller as the control target, and adopts the incremental digital PI control to obtain the differential torque of rear axle motor. Finally, a hardware-in-the-loop simulation is conducted to verify the control effect and real-time performance of differential steering of rear axle under medium and high speeds conditions. The results indicate that compared with the ideal Ackerman steering strategy, the strategy proposed can effectively reduce the centroid sideslip angle of vehicle in the process of steering and ensure steering stability.

Key words: differential steering, distributed drive, two-layer control strategy, fuzzy control, steering stability