Fuzzy logic controller for a vehicle active suspension system

An active suspension system has been proposed to improve the ride comfort. Its dynamic performance was investigated by using computer simulation results. A quarter-car 2 degree-of-freedom (DOF) system is designed and constructed on the basis of the concept of a four-wheel independent suspension to simulate the actions of an active vehicle suspension system. Since the mathematical model of this hydraulic actuating suspension system is non-linear and complicated, it is difficult to derive an accurate system model for designing a model-based controller. Therefore, a model-free fuzzy control algorithm is employed to design a controller for achieving vibration isolation. The experimental results show that the tyre deformation influences significantly the control performance of the active suspension system. Hence, a grey predictor is introduced to predict the tyre deformation and filter it from the feedback error signal. The control performance of this fuzzy control strategy with grey predictor is significantly improved.