Mixed internal model-based and feedforward control for robust tracking in nonlinear systems

The purpose of this paper is to compare different features of two approache s to the problem of tracking-prescribed trajectories in a nonlinear system, and to propose a possible merger of these approaches in what is called her e the problem of "Asymptotically Robust Perfect Tracking". The latter is th e problem of designing a feedforward/error-feedback control law achieving p erfect tracking in case the initial conditions of the system/exosystem are known and compatible with perfect tracking, and asymptotic tracking in all other cases. (C) 2000 Elsevier Science Ltd. All rights reserved.