Robust practical output tracking by dynamic output feedback for uncertain non-linear systems with unstabilisable and undetectable linearisation

Abstract: This paper studies the global robust practical output tracking problem using a dynamic output feedback controller (i.e., an output compensator) for a family of uncertain non-linear systems whose Jacobian linearisation may be unstabilisable and/or undetectable. It is shown that under some mild conditions on a given system, there is an output compensator achieving global robust practical output tracking and such a compensator is explicitly constructed by the ‘coupled controller-observer method’ recently proposed. The usefulness of our result is illustrated by some simple numerical examples.