Nonlinear observers for locally uniformly observable systems

¹ LAGEP, UMR 5007 du CNRS, Université Lyon 1, ESCPE Lyon, bâtiment 308G, 43 boulevard du 11 novembre 1918, 69622 Villeurbanne Cedex, France; hammouri@lagep.cpe.fr.
² LAP, EA 2611, ISMRA, Université de Caen, 6 boulevard du Maréchal Juin, 14050 Caen Cedex, France.

Received: 21 October 2002
Revised: 10 December 2002

Abstract

This paper deals with the observability analysis and the observer synthesis of a class of nonlinear systems. In the single output case, it is known [4-6] that systems which are observable independently of the inputs, admit an observable canonical form. These systems are called uniformly observable systems. Moreover, a high gain observer for these systems can be designed on the basis of this canonical form. In this paper, we extend the above results to multi-output uniformly observable systems. Corresponding canonical forms are presented and sufficient conditions which permit the design of constant and high gain observers for these systems are given.