Development of an Anthropomorphic Prosthetic Hand with Underactuated Mechanism

Wooseok Ryu,Youngjin Choi,Yeong Geol Lee,Yong Je Choi,Sungon Lee

doi:10.3390/app10124384

Wooseok Ryu, Youngjin Choi + Show 3 more

Open Access

https://doi.org/10.3390/app10124384

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Journal: Applied sciences	Publication Date: Jun 25, 2020
Citations: 13	License type: CC BY 4.0

Affiliation: Yonsei University, Hanyang University

Abstract

An anthropomorphic prosthetic hand for wrist or forearm amputees is developed herein. The prosthetic hand was designed with an underactuated mechanism, which makes self-adaptive grasping possible, as well as natural motions such as flexion and extension. The finger and thumb modules were designed with four degrees of freedom by motions of the distal interphalangeal, proximal interphalangeal, and metacarpophalangeal joints. In this research, we pursued several novel trials in prosthetic hand design. By using two four-bar linkages composed of a combination of linkages and gears for coupling joints at each finger, it was possible to make a compact design, and the linkage has advantages such as accurate positioning, uniform power transmission, and high payload. Also, by using constant-velocity joints, torque is transferred to finger modules regardless of adduction/abduction motions. In addition, adduction/abduction and self-adaptive grasping motions are passively realized using torsional springs. The developed prosthetic hand was fabricated with a weight of 475 g and a human hand size of 175 mm. Experiments with diverse objects showed its good functionality.

Highlights

For finger and forearm amputees, prosthetic and robotic hands of different types have been developed steadily, and human hand motions, such as natural and self-adaptive grasping motions, have been realized by anthropomorphic hands with various mechanism types and designs [1,2]
The DLR hand and Robonaut hand were developed with the objective of dexterous manipulation [3,4]
Grasping motion is an important function of the hand, and hands with an underactuated mechanism have a remarkable ability to grasp differently shaped objects adaptively because the control of robotic hands with multiple degrees of freedom (DOFs) becomes simple

Summary

Introduction

For finger and forearm amputees, prosthetic and robotic hands of different types have been developed steadily, and human hand motions, such as natural and self-adaptive grasping motions, have been realized by anthropomorphic hands with various mechanism types and designs [1,2]. Jing developed a biomimetic prosthetic hand with the aim of reducing weight and cost [5]. Grasping motion is an important function of the hand, and hands with an underactuated mechanism have a remarkable ability to grasp differently shaped objects adaptively because the control of robotic hands with multiple degrees of freedom (DOFs) becomes simple. When hands using an underactuated mechanism are designed, the description and design to realize the desired motions according to target grasping types become easier

Methods

Results

Conclusion