Robust hybrid impedance control of robot manipulators via a tracking control method

In this work, we address robust hybrid impedance control via a tracking control method. The objective of hybrid impedance control is converted into tracking a targeted trajectory. A globally asymptotically stable robust control law is proposed and applied to the tracking control of the targeted trajectory. The position and velocity tracking errors converge to zero under the proposed control law, and the force error is bounded. Furthermore, it is shown that the force error can be reduced by applying inner-loop acceleration feedback. The same controller can be used for control of both free and constraint motions of robot manipulator. As an illustration, an example is presented, and the simulation results are in accordance with the theoretical analysis