Multiple Impedance Control of Redundant Manipulators

Abstract

The Multiple Impedance control (MIC) enforces a designated impedance on all cooperating manipulators, and the manipulated object itself. A redundant manipulator exploits more degrees of freedom than those required to achieve the desired position and orientation of the end-effector. In this paper, the MIC law is extended to control cooperative redundant manipulators in the presence of impacts due to contact with the environment. Due to redundancy, the jacobian velocity matrix is non-squared. However, in the proposed method the adjustment of robot behavior is done without calculation of inverse of this jacobian matrix. The extended formulation of the MIC algorithm is presented, and a system of two cooperating redundant planar manipulators carrying a common object is studied. The obtained results show good tracking performance even in the presence of impacts due to contact with an obstacle, and also system flexibility. These results reveal the merits of MIC algorithm for object manipulation tasks with redundant arms, though it can be also implemented with obstacle avoidance strategies.