Tendon-driven Mechanism for Improvement of Grasping Capability

Abstract

This paper proposes a tendon-driven mechanism with a spring in order to improve a grasping stability of a robotic hand. The properties of the tendon drive system with an elasticity are investigated from the viewpoint of finger posture in numerical simulations. The grasping stability generally decreases when a grasping object is displaced by an external force affected. The stability decrement of the tendon-driven mechanism becomes less than that of the conventional joint drive system, because the joint drive system allows a fingertip to rotate following to the external force. As a result, the fingertip tends to slip at grasping point. On the other hand, a fingertip of the tendon-driven mechanism rotates in the opposite direction in the same case. Besides the tendon-driven system mechanically and simultaneously responds to the disturbance without a time delay because it does not requre any sensors and feedback systems.