Cooperative control of yaw and roll motion for in-wheel motor vehicle with semi-active suspension

A new vehicle motion control strategy is proposed, which synthesizes the rolling and yaw performance of vehicle by cooperating the damping force of semi-active suspension and yaw moment. To address the coupled dynamic behavior of roll and yaw motion, the modeling approach for nonlinear roll and yaw coupled dynamics is firstly employed. Furthermore, considering that the yaw and roll controllers are located in different electronic control units in practice, a distributed structure of cooperative control is presented. The key of cooperative control is that the damping force of semi-active suspension is controlled to adjust the roll dynamic, the front- and rear-axle load transfer cooperating the yaw motion; the yaw stability controller is designed to improve the yaw dynamic performance. To design the suspension damping force controller, the effect of the suspension damping force on roll and yaw dynamic behavior is discussed, and the piecewise-linear damping-force model with drive current as input is established. Moreover, the optimal suspension drive current is designed to alter roll performance and load transfer. To enhance the yaw dynamic performance, the yaw stability controller based on a sliding mode method is explored, and the optimal sliding-surface parameter is discussed to synthesize the settling time and overshoot of the yaw rate. Simulation and hardware-in-loop (HIL) test results show that the cooperative control combines the roll and yaw dynamics performance well; the overshoot and oscillation of yaw rate and lateral speed can be restrained.