An Underactuated Prosthetic Hand with Coupled Metacarpophalangeal Joints

Abstract

The design of a comfortable and functional prosthetic hand is still a challenge. This paper presents the design of a tendon-driven, 3D-printed, underactuated prosthetic hand. An improved structural design was developed to make the hand more flexible. Three fingers are equipped with abduction freedom at the metacarpophalangeal joints (MCP) to ensure natural enveloping for both cylinder and sphere-like objects. A force-sensing resistor (FSR) is adopted to measure the fingertip force of each finger. Experiments show that this type of structure design provides the hand with excellent dexterity, as the added abduction ensures natural enveloping grasp gestures for both cylinder and sphere-like objects. Moreover, a myoelectric control paradigm is implemented in the control system to demonstrate the feasibility.

A Single-Actuated, Cable-Driven, and Self-Contained Robotic Hand Designed for Adaptive Grasps

“…Through several research studies, the functionality of robotic hands has been improved by focusing on affordability, portability, weight, design simplicity, number of DOFs, number of actuators, and the ability to provide a safe, powerful, and robust grasp. The design requirements can be summarized in three basic design factors, namely anthropomorphic ( [1][2][3][4][5]), underactuated ([3,6-9]), and compliant ( [2,5,[10][11][12]) design. With an anthropomorphic design, hand DOFs and natural movements can be reproduced.…”

“…Developing compliant passive parts is a simple implementation of this idea. For instance, elastic elements or springs are used to passively model extension movement of the fingers [2,5,10,11]. Fully soft robotic hand designs using pneumatic actuators have also been proposed [12].…”