Study on coupled and self-adaptive finger for robot hand with parallel rack and belt mechanisms

This paper proposed a novel Coupling and Self-adaptive (COSA) grasping mode, aiming to overcome the disadvantages of the two main kinds of under-actuated fingers: coupled finger and self-adaptive finger. The COSA grasping mode includes 2 stages: coupling grasping and self-adaptive grasping. A 2-joint COSA finger (COSA-RB finger) was developed to demonstrate the new grasping function, based on a gear-rack mechanism and a pulley-belt mechanism. Force analyses and structure optimization rules of the new finger are given and discussed in detail. The experimental results show that the COSA grasping mode of the finger is effective. A highly under-actuated humanoid robot hand (TH-COSA-RB Hand) is designed based on the COSA grasping mode. The hand is more similar to human hand in appearances and actions, able to more dexterously and stably grasp different objects than traditional coupled or self-adaptive hands.