Optimal sliding mode control for active suspension systems

This paper presents a feedforward and feedback optimal sliding mode control design of active vehicle suspension system for quarter-car model with two-degree-of freedom. In some given conditions, the random road surface input firstly is formulated as the output variables of an exosystem. Then, by regarding some state variables of the suspension system as virtual control, the optimal sliding mode which consists of analytic term and a disturbances compensation term is obtained. The sliding mode control presented ensures the state trajectories reach the sliding surface in finite time and remain on it thereafter. Also, the sliding mode control can effectively attenuate random road surface disturbance. A numerical example is employed to verify the effectiveness of the proposed approach.