Abstract: The optimal control laws of 4WS on the complex typical path are studied using driver model of preview follower method based on the certain vehicle model considering roll, yaw and lateral motions. The actual vehicle model is considered as uncertain systems. The cornering stiffness of the front and rear wheels and outer disturbance vary over a limited range. The adaptive model-following variable structure control method is used for controlling the steering of front and rear wheels of the actual vehicle, so that the steering characteristics of uncertain vehicle model can follow the characteristics of reference model. Simulation results have demonstrated that the control system can overcome the drawbacks of parameter perturbations and outer disturbance.

Key words: 4WS, Complex path, Driver model, Uncertain model, Variable structure control