Adaptive Robust Motion and Force Tracking Control of Robot Manipulators in Contact With Compliant Surfaces With Unknown Stiffness

Abstract

High performance robust motion and force tracking control of robot manipulators in contact with compliant surfaces is considered in this paper. The robot parameters and the stiffness of the contact surface may not be known. The system may also be subjected to uncertain nonlinearities coming from the joint friction of the robot, external disturbances, the contact surface friction model, and the unknown time-varying equilibrium position of the contact surface. An adaptive robust motion and force tracking controller is proposed, which needs measurements of position, velocity, and interaction force only. The controller achieves a guaranteed transient performance and final tracking accuracy, a desirable feature for applications and for maintaining contact. In addition, the controller achieves asymptotic motion and force tracking without resorting to high-gain feedback when the system is subjected to parametric uncertainties.