State and input estimation for a class of uncertain systems

Abstract

We consider here the problem of state and input estimation for a class of uncertain systems which consist of a nominally linear part and an uncertain/nonlinear/time-varying part which can be regarded as a state-dependent/time-varying input. We obtain a Lyapunov-type characterization of the assumptions commonly found in the literature on this problem. Using this characterization, we obtain estimators which, using only a measured output, can asymptotically estimate to any desired accuracy the system state and the input. © 1998 Elsevier Science Ltd. All rights reserved.