Impedance control for multi-arm manipulation

In this paper a geometrically consistent impedance concept is applied to control a multi-arm system. The case of a common rigid object rigidly grasped by the manipulators in the system is considered. A 6-DOF impedance behaviour is enforced at the object level so as to limit the force/moment due to the interaction with an external environment. Moreover, in order to avoid large internal forces, a 6-DOF impedance behaviour is imposed at each end-effector. The adoption of the unit quaternion to describe object´s frame orientation ensures consistency with the task geometry. The overall control scheme is of inverse dynamics type with an inner motion loop which provides robustness to unmodeled dynamics and disturbances