Dexterity and versatility in the pinching motion of robot fingers with multi-degrees of freedom

Abstract

This paper focuses on dexterity and versatility in pinching a rectangular object by a pair of robot fingers based on sensory feedback. In the pinching motion of humans, it is possible to execute concurrent pinching and orientation control quickly and precisely by using only the thumb and index finger. However, it is not easy for robot fingers to perform such imposed tasks agilely and simultaneously. In the case of robotic grasping, to perform concurrently such plural tasks retards the convergence speed in the execution of the overall task. This means that in order to increase versatility by imposing additional tasks, dexterity in the execution of each task may deteriorate. In this paper it is shown that both dexterity and versatility in the execution of such imposed tasks can be enhanced remarkably, without any deterioration in dexterity in the execution of each task, by using a sensory feedback method based on the idea of role-sharing joint control which comes from observation of the functional role of each human finger joint.