Observer-based fuzzy sliding mode control for vehicle semi-active suspensions

This paper proposes a vehicle semi-active suspension system by using fuzzy sliding mode control (FSMC) with the filtered feedback scheme. Conventional approaches of direct state feedback control can not reduce the vibration in both above and below wheel frequency. To get over this limit, the filtered feedback scheme is augmented in the control system. For the full state feedback system, an observer is developed to estimate all system states. Fuzzy logic control (FLC) is employed to estimate the switching control gain of the sliding mode controller without need of the precise upper bound of system uncertainties in advance. The CarSim and SIMULINK co-simulation is used and a multi-body virtual prototype of sedan under a sine sweep of road profile is presented in CarSim software. The evaluation results show the superior performance of our approach in comparison with the built-in semi-active suspension system of CarSim, and the passive suspension system.