New approach to the design of robust tracking and model following controllers for uncertain delay systems

For a class of uncertain time-delay systems, a new approach to the design of robust tracking and model following controllers is presented. In the case that the system uncertainties satisfy the generalised matching conditions, the resultant linear controller guarantees uniform ultimate boundedness of the tracking error, and furthermore the error bound can be made arbitrarily small. In the case of mismatched uncertainties, a sufficient condition is presented such that the controller ensures ultimate boundedness of the tracking error. The main feature of this approach is that much larger system uncertainties arising in the control matrix can be admitted. Two numerical examples are included to show the effectiveness of the approach.