High performance anthropomorphic robot hand with grasp force magnification mechanism

This paper presents a lightweight 328 g anthropomorphic robot hand that can exert a large grasp force. We propose a combination mechanism of a flexion-drive and a force-magnification-drive for a cable driven multifingered robot hand. The flexion-drive consisting of a feed screw enables quick motion of its fingers and the force-magnification-drive consisting of an eccentric cam, a bearing and a pulley enables a firm grasp. This paper also proposes a three-dimensional linkage for the thumb. This linkage consists of four links and is driven by a feed screw. It can oppose to a large force exerted by the other fingers with the force-magnification-drive. These mechanisms are compact enough to be installed in the developed lightweight hand. We experimentally verify that the maximum fingertip force of the hand exceeds 20 N and that the thumb can hold a large force of 100 N. The time to fully close the hand by using the flexion-drives is 0.47 s. After the fingers make contact with an object, the time to achieve a firm grasp by using the grasp-magnification-drive is approximately 1 s.