Robust low-order control of a generic flexible test structure

The design of robust low-order controllers based on a high-order model of a generic flexible test structure with collocated sensors/actuators is considered. A synthesis technique which combines the projective and the positive real control concepts is developed and used for control design. The method not only alleviates the known difficulty of the projective approach, where the residual (nonretained) closed-loop modes can become unstable, but also guarantees the strictly positive realness of the controller. Two approaches for selecting the free design parameters are provided. Based on this technique, two global controllers and one decentralized controller are designed, and their performance is evaluated and compared