Certainty equivalence in nonlinear output regulation with unmeasurable regulated error

In the present paper we consider a general nonlinear output regulation problem in which the regulated error is unmeasurable. It is assumed that the interconnection of the controlled plant with the exosystem observed through the measured output satisfies some appropriate observability conditions that allow the design of an asymptotic observer. Then, the contribution of this paper consists in showing that in the latter scenario, a design based on certainty equivalence is effective for determining a controller that achieves semiglobal output regulation. Copyright © 2007 International Federation of Automatic Control All Rights Reserved.