Noncontact impedance control for redundant manipulators

Abstract—This paper proposes an impedance control method that can regulate a virtual impedance between a robot ma-nipulator and external objects using visual information. The conventional impedance control method is not useful in some cases where no interaction force between the arm and its en-vironment exists, although it is one of the most effective control methods for manipulators in contact with the environment. Using the proposed method, we can control the manipulator motion based on the virtual impedance before contact with the objects. The validity of the proposed method is verified through computer simulations and experiments using a direct-drive robot. Index Terms—Impedance control, manipulators, motion-plan-ning, redundancy, robot dynamics, robot vision systems. I