Decentralized adaptive compliance control of robot manipulators

Abstract This paper presents two decentralized adaptive schemes for controlling the end-effector compliance of robot manipulators. The first scheme is developed using an adaptive impedance control approach for torque-controlled manipulators, while the second strategy is an adaptive admittance controller for position-controlled manipulators. The proposed controllers are very general and computationally efficient since they do not require knowledge of the manipulator dynamic model or parameter values of the manipulator or the environment. It is shown that the control strategies are globally stable in the presence of bounded disturbances, and that in the absence of disturbances the ultimate bound on the size of the system errors can be made arbitrarily small. The capabilities of the proposed control schemes are illustrated though laboratory experiments with a Robotics Research Corporation seven degree-of-freedom (DOF) manipulator.