DESIGN OF ROBUST ADAPTIVE CONTROLLERS FOR NONLINEAR-SYSTEMS WITH DYNAMIC UNCERTAINTIES

In this paper, a modified adaptive backstepping design procedure is pr oposed for a class of nonlinear systems with three types of uncertaint y: (i) unknown parameters; (ii) uncertain nonlinearities and (iii) unm odeled dynamics. Nonlinear damping terms are used to counteract the un certain nonlinear functions and a dynamic signal is introduced to domi nate the dynamic disturbance. The derived adaptive controller guarante es the global boundedness property for all signals and states and at t he same time, steers the output to a small neighborhood of the origin. Incidentally an adaptive output-feedback control problem is solved. ( C) 1998 Elsevier Science Ltd. All rights reserved.