Adaptive robust H∞ dynamic output feedback for continuous time-varying uncertain systems

The problem of designing an adaptive robust H_infin dynamic output feedback controller for uncertain linear systems is considered. The uncertainties are assumed to be time-varying, unknown, but bounded, which appear affinely in the matrices of system model. Based on the online estimations of uncertain parameters, a robust dynamic output feedback controller with variable gains is constructed to compensate the effect of uncertainty on systems. An adaptive mechanism is introduced to estimate uncertain parameters according to the designed adaptive laws and to enhance system performance. New sufficient conditions with less conservativeness than those of traditional robust controllers are also derived to guarantee the stability and H_infin performance of the closed-loop systems. A numerical example is given to illustrate the effectiveness of the proposed method.