2 Observer Design for Nonlinear Systems

Abstract

In this chapter, an overview of main observability problems and possible observer designs for nonlinear systems is proposed. In particular the observer problem and related observability conditions are first given. Then, some basic designs are reviewed, divided into Luenberger-like designs for socalled uniformly observable systems, and Kalman-like designs for non uniformly observable ones. Finally, two directions for more advanced designs – in the sense that they are based on the previously listed ones – are proposed: designs based on observer interconnections on the one hand, and designs based on system transformations on the other hand.