Manipulation of Enveloped Multiple Objects

This paper discusses the manipulation of multiple objects grasped by the enveloping grasp. In case of the enveloping grasp, since the contact force cannot be uniquely determined for a given joint torque, the resultant force also cannot be obtained uniquely. We derive a joint torque set enabling the resultant force set directing the desired direction. First, we extract the feature of the contact force for the enveloping grasp of multiple objects. Based on the analysis, we show the method to calculate the resultant force set. Then, we formulate the way to obtain the joint torque. Lastly, to show the effectiveness of the proposed method, a numerical example is shown.