Stabilization of vibration systems via delayed state difference feedback

This paper presents a study of the stabilization problem, via delayed state feedback of Pyragas type, for unstable vibration systems that have even number of characteristic roots with positive real parts. On the basis of stability switches with respect to the time delay, a new stabilization criterion is established, and an effective procedure for determining the admissible values of the feedback gains and the delay is given. Two examples are given in detail to demonstrate the efficiency of the theory.