Force/Position Regulation of Robot Manipulators with Gravity Parameter Adaptation

Abstract The problem of force/position regulation of robot manipulators in contact with an elastically compliant surface is considered in this work. A control scheme was recently proposed which consists of a PD action on the position loop, a PI action on the force loop, together with gravity compensation and desired contact force feedforward. In this work local asymptotic stability is proved in the case of imperfect gravity compensation. The original controller is then made adaptive with respect to a suitable set of parameters in the gravity term. Numerical case studies are developed for a three-joint industrial manipulator.