ER 댐퍼를 이용한 차량 현가장치 시스템의 이산시간 퍼지 슬라이딩 모드 제어

This paper presents control characteristics of a quarter-vehicle electrorheological(ER) suspension system by adopting a discrete-time fuzzy sliding mode control algorithm. A cylindrical ER damper is designed and manufactured by incorporating Bingham model of the ER fluid. After evaluating the field-dependent damping characteristics of the ER damper, a quarter-vehicle ER suspension system is constructed which is composed of sprung mass, ER damper, spring and tire. After deriving the governing equation of motion for the quarter-vehicle ER suspension system, a discrete-time control model with system uncertainties is formulated in a state space. A stable sliding surface is then designed followed by the formulations of a discrete-time sliding mode controller which consists of a discontinuous part and an equivalent part. In the controller formulation, the fuzzy control algorithm is also adopted to increase system robustness to the uncertainties and achieve faster reaching to the sliding surface. The controller is then realized and control performance is compared with the performance of continuous-time sliding mode controller.