Global impedance control of dual-arm manipulation for safe interaction

The impedance control of dual-arm 7-DOF cooperative manipulators is considered in this paper. Global compliant behavior for the whole system is achieved using impedance at three levels, i.e. object, end-effector and body level. A centralized impedance control strategy is provided to confer a compliant behavior to the object, while an active decentralized impedance control with force tracking is enforced to the end-effectors to control the internal forces on the object. A compliant behavior for the body of the dual-arm system is obtained by means of null-space impedance control. The manipulability measure of the whole system is locally maximized within this algorithm. The developed control scheme is verified in a simulation environment composed of two cooperating 7-DOF KUKA lightweight arms carrying a common object.