A Methodology to Design a Variable Resistance Hand Exerciser using a Compliant Mechanism

Abstract

The design of an effective hand-exercising device is based on an existing study of the force-deflection behavior of the human hand. This paper presents a design methodology using a compliant mechanism construct, for generating the desired force-deflection profile as the output. This is made possible by the integration of a rigid cam profile segment. The compliant segments serve as the followers, and their material and geometric properties serve as design variables. The force-deflection profile utilized was developed through experimental studies conducted on the human hand, along with a mathematical model that predicts the maximum grip force as a function of the handle’s diameter. A procedure is proposed herein that would allow the use of various force-deflection profiles, to be able to change the resistance level in order to meet individual requirements. The synthesis results obtained are investigated for cam-follower non-interference using a novel pseudo-rigid-body model (PRBM) approach and verified by finite element analysis. The exercise devices generally ignore in their conceptualization and design the anatomical mechanical advantage. This methodology, owing to the nature of the experiment, duly regards the variable mechanical advantage characteristic of the hand in different positions naturally.

Meeting Name

ASME Design Engineering Technical Conference, IDETC-CIE 2020 (2020: Aug. 17-19, Virtual)

Department(s)

Mechanical and Aerospace Engineering

Keywords and Phrases

Compliant cam-follower design; Compliant mechanism; Force-deflection profile; Grip strength; Mechanical advantage; Pseudo-rigid-body model; The human hand

International Standard Book Number (ISBN)

978-079188399-0

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2020 American Society of Mechanical Engineers (ASME), All rights reserved.

Publication Date

19 Aug 2020

Link to Full Text

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