Coordinated control of active front steering and direct yaw moment control for in-wheel-motor-drive electric vehicles

In this paper, a hierarchical control scheme is proposed to improve trajectory tracking ability and lateral stability for in-wheel-motor-drive electric vehicles via coordinating active front steering (AFS) and direct yaw moment control (DYC). It consists of three layers, i.e., the upper, the intermediate and the lower layer. Firstly, the upper layer controller calculates the desired additional yaw moment based on the sliding mode control (SMC) algorithm for ensuring vehicle dynamics stability. Then, the intermediate layer controller decides the working areas of the two subsystems based on the working conditions of tires. Finally, the lower layer controller coordinates the AFS and DYC subsystems for enhanced vehicle lateral stability. Simulink/CARSIM co-simulation results show that the proposed coordinated control scheme outperforms the DYC-only control in both path following performance and vehicle lateral stability under typical maneuvers.