Adaptive Robust Control Synthesis for Linear Systems with Time-Varying Uncertainties

This paper describes the synthesis of robust H _infin state feedback controllers for linear systems with time-varying uncertainties. The uncertainties are assumed to be time-varying, unknown, but bounded. An adaptive mechanism is introduced to reduce the conservativeness inherent in standard quadratic H _infin, performance design method. The controller parameters are updated automatically according to the online estimations of uncertain parameters. A new sufficient condition is also given in the framework of linear matrix inequalities (LMIs) to guarantee the asymptotically stability and H _infin performance of the uncertain closed-loop system. The advantage of the proposed method is demonstrated by way of an example.