Augmented system approach to measurement-based robust tracking

This paper considers the robust tracking problem using an augmented system approach. Our results extend previous full-state results to observer-based feedback. The system matrix is assumed to contain time-invariant uncertainty. Two cases are considered. In the first, the tracked output is available for feedback. The resulting control law call be applied to polynomial reference signals of known order and results in zero steady-state error. In the second case, where the tracked output is not available for feedback, our approach is restricted to step references, and the steady-state error is non-zero, although bounded by a prescribed value.