Output Regulation for Output Feedback Systems with An Uncertain Exosystem

This paper studies the global robust output regulation problem for a class of output feedback systems subject to an uncertain exosystem by using output feedback control. An adaptive control technique is used to handle the unknown parameter vector in the exosystem. It is shown that this unknown parameter vector can be exactly estimated asymptotically if the controller incorporates a minimal internal model. The effectiveness of our approach has been illustrated by an asymptotic tracking problem associated with a generalized fourth-order Lorenz system.