Model and Analysis of the Interaction Dynamics in Cooperative Manipulation Tasks

Efficient coordination of a multirobot team is the key challenge in robotic application domains such as manufacturing, construction, and service robotics. In cooperative manipulation tasks, the system dynamics result from the complex interaction of several manipulators handling a common object. A comprehensive model is indispensable for a sophisticated model-based control design. An open problem is the modeling and analysis of the overall system dynamics including the manipulators' interaction wrenches. Based on the apparent end-effector dynamics in task space, in this paper we focus on the characterization of the interaction effects when manipulating a common object. We note the central role of the imposed kinematic constraints for the emerging system dynamics, their significance for the manipulator coordination in terms of control design, and the analysis of internal wrenches applied to the object. We derive fundamental properties of the cooperative manipulator system relevant to the manipulation task such as the apparent impedance with respect to external disturbances. An experimental study is conducted with two cooperating anthropomorphic manipulators supporting the relevance of our findings.