Robust Dynamic Output Feedback Guaranteed Cost Control for Discrete-Time Systems with Time-Varying Delays

The paper proposes a dynamic output feedback guaranteed cost control for uncertain discrete-time delay systems, where the unknown nonlinearities/uncertainties of the system are permitted to take their values in a fairly general set. The delays are considered to be unknown time varying functions with known bounds. A sufficient condition for the existence of the guaranteed cost control is given by matrix inequalities. It is shown how these inequalities can be traced back to linear matrix inequalities. An iterative algorithm is proposed to improve the quality of the control by minimizing the upper bound of the cost function. Numerical examples illustrate the effectiveness of the proposed method.