Vibration control of vehicle ER suspension system using fuzzy moving sliding mode controller

This paper presents robust vibration control performances of an electrorheological (ER) suspension system subjected to parameter uncertainty. A cylindrical type of ER damper is designed and manufactured on the basis of the required damping force level for a middle-sized passenger vehicle, and its field-dependent damping force and dynamic characteristics are experimentally evaluated. The ER damper is then incorporated to a quarter vehicle suspension system which is composed of sprung mass, spring and tire. After formulating the governing equation of motion of the proposed ER suspension system with parameter variations, a new moving sliding mode controller (MSMC) is formulated by adopting the fuzzy logic for the moving algorithm. The fuzzy MSMC is then experimentally realized with the quarter vehicle for the demonstration of a practical feasibility. Control performances such as vertical displacement and acceleration are evaluated in time and frequency domains under various road conditions. In addition, in order to verify the effectiveness of the proposed control strategy a comparative work between the proposed controller and conventional controllers such as sky-hook controller is undertaken.