Sliding-mode control of four wheel steering systems

In this paper, a sliding mode control of active four-wheel steering systems is proposed in order to improve vehicle handling stability. An integral time-variant sliding surface is adopted to eliminate steady state errors, and a smooth function is used to alleviate the chattering effect. Dynamic responses of the front-wheel steering vehicles, the active four-wheel steering vehicles with LQR control and the active four-wheel steering vehicles with sliding mode control were compared. Simulation results show that the sliding mode control can track the ideal reference model and resist external disturbances.