State observers for rigid and elastic joint robots

Abstract

This paper refers to the design of nonlinear observers for robot manipulators. Robots without and with elasticity in the joints are analyzed. In both cases, the uniform asymptotic stability of the error dynamics is proved and some separation and robustness properties are derived. The observer design is accomplished by exploiting the structural properties of the robot dynamics. The proposed observation algorithms have no need of coordinate changes, thus simplifying the observer implementation.