Variable structure model following control of active four-wheel-steering vehicle based on the optimal reference model

The optimal control laws of 4WS during single lane-change are studied using the driver model of the preview follower method based on a certain vehicle model. The actual vehicle models are considered as uncertain systems. The cornering stiffness of the front and rear wheels and outer disturbance vary over a limited range. An adaptative 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 an uncertain vehicle model can follow the characteristics of a reference model. Simulation results have demonstrated that the control system can overcome the drawbacks of parameter perturbations and outer disturbances.