Improvement of vehicle handling and stability by integrated control of four wheel steering and direct yaw moment

This study proposes a new vehicle integrated robust model matching controller (R-MMC) that cooperates four wheel steering and direct yaw moment control to improve the vehicle handling performance and stability. The design frame work of the R-MMC is based on linear matrix inequalities (LMIs) in this study. Since vehicle sideslip angle measurement is difficult to achieve in practice, a LMI-based sliding mode observer (SMO) that requires only vehicle yaw rate as the measured input is also developed. The performance and robustness of the SMO and the integrated controller are demonstrated under critical steering maneuvers and road surface conditions. Simulation results reveal the satisfactory tracking ability of the SMO, and the superior improved vehicle handling performance, stability and robustness of the integrated control vehicle.