Learning control for geometrically constrained robot manipulators

Abstract

A learning control scheme for class of robot manipulators whose endpoint is moving under geometrical constraints on a surface is proposed. In this scheme, the input torque command is composed of two different signals updated separately at every trial by different laws. One is updated by the angular velocity error vector which is projected to the tangent plane of the constraint surface in joint space. The other is updated by the magnitude of contact force error at the manipulator endpoint. A theoretical proof of the uniform boundedness of velocity and position trajectory errors and the convergence of their desired trajectories is given. In addition, a theoretical proof of the convergence of force errors when velocity and position trajectories are in a neighborhood of the desired ones is presented. Computer simulation results for a 3 DOF manipulator are given.