An output regulation perspective on the model reference adaptive control problem

The paper presents a connection between the classic model reference adaptive control and recent developments in the theory of adaptive output regulation. Specifically, it is shown how the certaintyequivalence model reference controller realizes an internal model of an extended exogenous system comprising the zero dynamics of the plant driven by the steady-state trajectories of the reference model. Furthermore, the classic nonminimal realization of the certaintyequivalence controller required for adaptive redesign is equivalent to a canonical parameterization of the internal model in question, achieved via a nonobservable (but detectable) system immersion.Copyright (c) 2012 John Wiley & Sons, Ltd.