Vibration control of magnetorheological damper system subjected to parameter variations

This paper presents vibration control of a semi-active magnetorhological (MR) suspension system subjected to parameter variations. After manufacturing the cylindrical MR damper, the field-dependent damping force and its controllability are experimentally evaluated. The full vehicle model is then derived by considering vertical, pitch and roll motions. A robust H-infinity controller is formulated by treating the sprung mass as parameter variation. This is accomplished by adopting the loop shaping design procedure. In order to demonstrate the effectiveness and robustness of the proposed control system, the Hardware-In-The-Loop Simulation (HILS) methodology is adopted by integrating the suspension model with the proposed MR damper. Vibration control responses of the vehicle suspension system such as vertical acceleration are evaluated under both bump and random road conditions.