Robust linearization and,control of robot arm using acceleration feedback

This paper presents a motion control algorithm of a robot arm using acceleration feedback in a task coordinate system. The acceleration feed back is used in order to linearize the nonlinear dynamics of a robot arm in a task coordinate system, when the uncertainties of parameters of the robot arm dynamics exist. First, we consider the nonlinear feedback, which linearizes the nonlinear dynamics of a robot arm in a task coordinate system, and discuss the effect of uncertainties of parameters, which are used for the calculation of nonlinear feedback. Then the use of acceleration feedback is discussed in order to eliminate the effect of parameter uncertainties. The total control system is designed for the linearized robot arm in a task coordinate system. Both the proposed control algorithm and the conventional resolved acceleration control algorithm are experimentally applied to a direct-drive arm with two degrees of freedom. Experimental results illustrate the validity of the proposed control algorithm.