Design of reduced-order robust controllers for flexible structural systems

An approach of designing reduced-order robust controller for active vibration control of a flexible plate structure is presented in this paper. FU-based robust output feedback control law is designed by using specific transformations of Lyapunov variable with appropriate linearizing transformations of the control variables, which gives rise to a tractable and practical LMI formulation of the vibration control problem. In terms of LMI technique, an H/sub /spl infin// output feedback controller is designed to suppress the low-frequency vibrations caused by external disturbances and to guarantee the stability and performance of the closed-loop system under uncertainties. The order of the controller is further reduced through an iterative two-step LMI-based algorithm for the frequency weighted model reduction problem. The efficiency of the approach is validated by numerical simulation studies of active vibration suppression for the flexible plate.