Field Test on Vibration Control of Vehicle Suspension System Featuring ER Shock Absorbers

This study presents vibration control responses of a passenger vehicle equipped with continuously controllable electrorheological (ER) shock absorbers. As a first step, four ER shock absorbers (two for front parts and two for rear parts) are designed and manufactured based on the damping force levels and mechanical dimensions required for the middle-sized passenger vehicle. After experimentally evaluating the field-dependent damping force property and controllability, the manufactured ER shock absorbers are incorporated with the suspension of a car to be tested. Subsequently, the skyhook control algorithm, which is simple, but very effective in real field, is formulated by considering vertical, pitch, and roll motions. The controller is then realized by integrating feedback sensors, such as accelerometer and the field test is undertaken under bump and random road conditions. The control responses for the ride quality and steering stability are evaluated in both time and frequency domains. In addition, the performance comparison between conventional suspension and ER suspension is carried out.