Adaptive output feedback regulation with almost disturbance decoupling for nonlinearly parameterized systems

In this paper we design output feedback control algorithms for uncertain systems with output depending nonlinearities: the uncertainties (disturbances or time-varying parameters) are modelled as a bounded time-varying vector which is allowed to enter nonlinearly in the state equations. We first design an almost disturbance decoupling control which contains a positive scalar parameter so that both the L-2- and the L-infinity-induced norms between the disturbance vector and the tracking vector may be arbitrarily improved. We then incorporate an adaptive part in the controller so that, in addition, the tracking error asymptotically vanishes when both reference signals and disturbances become constant. Copyright (C) 2000 John Wiley & Sons, Ltd.