A Multifingered Hand with Three Coupled Four-bar Mechanisms

Abstract

Myoelectric prosthetic hands should be lighter in weight and maintainable, and able to exert large grip force to comfortably substitute the upper limb of amputees in daily life. This means it requires a lighter and simplified system whilst maintaining grip force. In this paper, we propose a five-fingered mechanical hand which each finger is comprised of three coupled four-bar mechanism. And three fingers of them is connected to a balance joint driven by a servo motor for adaptive grasping. We examined this mechanism's grip force and compliance performed by three small RC servo motors. The result shows that the hand can grasp several kinds of objects used in daily life weighing up to 2kg, in addition to being lightweight.