Underactuated Finger Design: A Minimalistic Approach Toward Biomimetic Prosthetic Finger

Dexterous prosthetic hands with a simple design are the need of the hour. The limiting factor for prosthetic hands is the structure, functionality, and control of the fingers and the thumb. Traditionally, robotic fingers used in prosthetic hands are tendon-driven or have linkage-based mechanisms. Wh...

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Main Authors: Vignesh Sompur, Varadhan Skm, Asokan Thondiyath
Format: Article
Language:English
Published: IEEE 2025-01-01
Series:IEEE Access
Subjects:
Online Access:https://ieeexplore.ieee.org/document/11008577/
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author Vignesh Sompur
Varadhan Skm
Asokan Thondiyath
author_facet Vignesh Sompur
Varadhan Skm
Asokan Thondiyath
author_sort Vignesh Sompur
collection DOAJ
description Dexterous prosthetic hands with a simple design are the need of the hour. The limiting factor for prosthetic hands is the structure, functionality, and control of the fingers and the thumb. Traditionally, robotic fingers used in prosthetic hands are tendon-driven or have linkage-based mechanisms. While tendon-driven mechanisms provide anthropomorphic behaviour, they lack sufficient grip force. In contrast, linkage mechanisms develop sufficient grip force but at the expense of the size and weight of the overall design. Further, a linkage-based mechanism provides only shape adaptation without joint coupling. To address this gap in prosthetic finger design, we propose a novel underactuated, hybrid, and minimalistic finger mechanism to achieve simultaneous coupling and self-adaptation. The designed finger mechanism has three degrees of freedom provided by two 4-bar mechanisms in series, with two degrees of actuation. The finger is actuated through a pair of inelastic tendons acting on two joints. The tendon architecture is bio-inspired and improves the finger mechanism’s anthropomorphic behaviour. A detailed kinematic and static analysis is provided to describe the finger design’s operating principle and construction. Simulations of fingertip trajectory and contact forces are also performed. Additionally, a prototype of the mechanism was 3D printed to validate the design of the finger. Grasping simulations and experiments were also performed for a typical 4-bar-based finger mechanism. The results show improved anthropomorphic motion and increased contact forces for the current finger design compared to the conventional 4-bar mechanism-based prosthetic finger.
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spelling doaj-art-061fb4b84a63433a8b1eafcd89926cf12025-08-20T03:24:56ZengIEEEIEEE Access2169-35362025-01-0113965179653410.1109/ACCESS.2025.357224111008577Underactuated Finger Design: A Minimalistic Approach Toward Biomimetic Prosthetic FingerVignesh Sompur0https://orcid.org/0000-0002-0833-4537Varadhan Skm1https://orcid.org/0000-0002-5746-2340Asokan Thondiyath2https://orcid.org/0000-0002-5474-3999Department of Engineering Design, Indian Institute of Technology Madras, Chennai, IndiaDepartment of Applied Mechanics and Biomedical Engineering, Indian Institute of Technology Madras, Chennai, IndiaDepartment of Engineering Design, Indian Institute of Technology Madras, Chennai, IndiaDexterous prosthetic hands with a simple design are the need of the hour. The limiting factor for prosthetic hands is the structure, functionality, and control of the fingers and the thumb. Traditionally, robotic fingers used in prosthetic hands are tendon-driven or have linkage-based mechanisms. While tendon-driven mechanisms provide anthropomorphic behaviour, they lack sufficient grip force. In contrast, linkage mechanisms develop sufficient grip force but at the expense of the size and weight of the overall design. Further, a linkage-based mechanism provides only shape adaptation without joint coupling. To address this gap in prosthetic finger design, we propose a novel underactuated, hybrid, and minimalistic finger mechanism to achieve simultaneous coupling and self-adaptation. The designed finger mechanism has three degrees of freedom provided by two 4-bar mechanisms in series, with two degrees of actuation. The finger is actuated through a pair of inelastic tendons acting on two joints. The tendon architecture is bio-inspired and improves the finger mechanism’s anthropomorphic behaviour. A detailed kinematic and static analysis is provided to describe the finger design’s operating principle and construction. Simulations of fingertip trajectory and contact forces are also performed. Additionally, a prototype of the mechanism was 3D printed to validate the design of the finger. Grasping simulations and experiments were also performed for a typical 4-bar-based finger mechanism. The results show improved anthropomorphic motion and increased contact forces for the current finger design compared to the conventional 4-bar mechanism-based prosthetic finger.https://ieeexplore.ieee.org/document/11008577/Biomimetic designfinger anthropomorphic indexmechanism synthesisprosthetic finger designunderactuation
spellingShingle Vignesh Sompur
Varadhan Skm
Asokan Thondiyath
Underactuated Finger Design: A Minimalistic Approach Toward Biomimetic Prosthetic Finger
IEEE Access
Biomimetic design
finger anthropomorphic index
mechanism synthesis
prosthetic finger design
underactuation
title Underactuated Finger Design: A Minimalistic Approach Toward Biomimetic Prosthetic Finger
title_full Underactuated Finger Design: A Minimalistic Approach Toward Biomimetic Prosthetic Finger
title_fullStr Underactuated Finger Design: A Minimalistic Approach Toward Biomimetic Prosthetic Finger
title_full_unstemmed Underactuated Finger Design: A Minimalistic Approach Toward Biomimetic Prosthetic Finger
title_short Underactuated Finger Design: A Minimalistic Approach Toward Biomimetic Prosthetic Finger
title_sort underactuated finger design a minimalistic approach toward biomimetic prosthetic finger
topic Biomimetic design
finger anthropomorphic index
mechanism synthesis
prosthetic finger design
underactuation
url https://ieeexplore.ieee.org/document/11008577/
work_keys_str_mv AT vigneshsompur underactuatedfingerdesignaminimalisticapproachtowardbiomimeticprostheticfinger
AT varadhanskm underactuatedfingerdesignaminimalisticapproachtowardbiomimeticprostheticfinger
AT asokanthondiyath underactuatedfingerdesignaminimalisticapproachtowardbiomimeticprostheticfinger