Robust controller for active vibration control of flexible systems

In this paper an active vibration controller for flexible systems is developed using a sliding manifold approach. The sliding surface consists of a time-invarying part which `eliminates' the selected modes without affecting the other dynamics, and a time-varying part which bounds the control amplitude and its rate in the transient. If the state is not available an observer is needed to implement the control law. In particular, a time varying term is introduced in the observer in order to avoid peaking phenomena. Moreover it is shown that it is possible to asymptotically recover the state feedback performance using a modified LTR procedure. The proposed control strategy reduces the excitation of the high frequencies modes, hence reducing the spillover phenomenon.