Model-Following Control of Nonlinear Elastic Joint Robots

Abstract

In this paper we study model-following control of manipulators with elastic joints. In the dynamic model of manipulators, the function of the joint flexibility may be nonlinear. A simple design procedure based on the notion of the Lie derivative is given. Checking of the involutivity conditions is not required. The nonlinear system will be linearized by the nonlinear state feedback and nonlinear state transformation. It is shown that the output converges to the model asymptotically, and the state is bounded. It is also shown that the proposed control method can be applied to a broad class of nonlinear functions of the joint flexibility.