Robust low-order control design of a generic flexible test structure

The design of robust low-order controllers based on a high-order model of a generic flexible space test structure with collocated sensors/actuators is considered. A new synthesis technique which combines the projective and the positive-real control concepts is developed and used for control design. The proposed method alleviates the known difficulty of the projective approach where the residual (nonretained) closed-loop modes can become unstable, and guarantees the strictly positive realness of the controller. Two approaches for selecting the free design parameters of the design technique are provided. Based on the new technique, two global controllers and one decentralised controller are designed with their performance evaluated and compared.