A modified structure internal model robust control method for the integration of active front steering and direct yaw moment control

Abstract

Taking into account the nonlinearity of vehicle dynamics and the variations of vehicle parameters, the integrated control strategy for active front steering (AFS) and direct yaw control (DYC) that can maintain the performance and robustness is a key issue to be researched. Currently, the H ∞ method is widely applied to the integrated control of chassis dynamics, but it always sacrifices the performance in order to enhance the stability. The modified structure internal model robust control (MSIMC) obtained by modifying internal model control (IMC) structure is proposed for the integrated control of AFS and DYC to surmount the conflict between performance and robustness. Double lane change (DLC) simulation is developed to compare the performance and the stability of the MSIMC strategy, the PID controller based on the reference vehicle model and the H ∞ controller. Simulation results show that the PID controller may oscillate and go into instability in severe driving conditions because of large variations of tire parameters, the H ∞ controller sacrifices the performance in order to enhance the stability, and only the MSIMC controller can both ensure the robustness and the high performance of the integrated control of AFS and DYC.