Yaw-rate control for electric vehicle with active front/rear steering and driving/braking force distribution of rear wheels

Direct yaw-moment control (DYC) is an effective method to make vehicle motion stable. In the DYC of vehicles having in-wheel motors and both active front steering system and active rear steering system, the control input generally has redundancy. The input variables can not be decided uniquely to generate the same yaw-moment. The equalization of workload for each wheel by the longitudinal force and lateral force distribution enhances vehicle cornering performance. Therefore, we propose the longitudinal force and lateral force distribution method based on least squares solution of equations of longitudinal, lateral and yawing motion in this paper. Moreover, we propose a method of lateral force control and a method of yaw moment compensation to attenuate tracking error in this controller. we show that the equalization of workload for each wheel and quick yaw-rate response are achieved in the proposed methods. Simulations and experiments are carried out to confirm effectiveness of the proposed methods.