A New Concept in Semi-Active Vibration Isolation

Abstract

Semi-active suspensions can achieve performance close to that of active suspensions with much lower cost and complexity. They use an active damper in parallel with a passive spring. The forces in the damper are generated merely by the modulation of fluid-flow orifices based on a control scheme involving feedback variables. This paper presents an original control strategy employing only directly measurable variables in vehicle applications. The relative displacement and relative velocity across the suspension are the only feedback signals and the damper force can be continuously modulated (as opposed to on-off control). Vibration isolation performance of the new semi-active scheme is compared to semi-active sky-hook suspension, as well as passive and active suspensions.