Robust tracking controllers of uncertain delay systems

A procedure for determining robust tracking control laws for a class of linear uncertain time-delay systems is presented. The system is controlled to track a dynamic input generated from a reference model. In the case that the system uncertainties satisfy the generalized matching conditions, by using the proposed linear controller, the ultimate bound of the tracking error can be made arbitrarily small and, therefore, the system practically tracks the reference model. In the case of mismatched uncertainties, we present a sufficient condition such that the designed controller guarantees ultimate boundedness of the tracking error. Compared with the existing results, our approach admits much larger system uncertainties in the control matrix. Numerical examples show that the resultant linear robust tracking controllers are less conservative.