Abstract:

To improve the lateral stability of four-in-wheel-motor-drive vehicles， in this paper a chassis coordinated control strategy that integrates torque coordination and active rear steering is proposed. The strategy aims to track the ideal yaw rate and sideslip angle while effectively reduce the body roll motion. Based on the characteristics of the vertical reaction force generated by the in-wheel motor， the decoupled control for the longitudinal， yaw and roll motions of the vehicles is designed based on torque coordination. To decrease the effect of ignored nonlinearity and uncertainty in modeling lateral dynamics on the control performance， a disturbance observer-based model predictive control for chassis cooperative control is designed to estimate and compensate the nonlinearity and uncertainty. To verify the effectiveness of the proposed method， a hardware-in-the-loop test is conducted for the double lane change maneuver. The results show that the proposed control strategy can improve the lateral stability and reduce the roll motion of the vehicle body. Furthermore， compared to the control without disturbance compensation， the disturbance observer-based control reduces the tracking errors of the desired yaw rate and sideslip angle by 56.9% and 27.3%， and the body roll angle and roll rate by 8.9% and 12.5%， respectively.

Key words: in-wheel motor drive, lateral stability, rear steering, disturbance observer, torque coordination, model predictive control