OBSERVER DESIGN FOR A CLASS OF NONLINEAR-SYSTEMS

A viable design methodology to construct observers for a class of nonl inear systems is developed. The proposed technique is based on the off -line solution of a Riccati equation, and can be solved using commerci ally available software packages. For globally valid results, the clas s of systems considered is characterized by globally Lipschitz nonline arities. Local results relax this assumption to only a local requireme nt. For a more general description of nonlinear systems, the methodolo gy yields approximate observers, locally. The proposed theory is used to design an observer for a single-link flexible joint robot. This obs erver estimates the robot link variables based on the joint measuremen ts.