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RESEARCH ARTICLE

Fast 3D Modeling of Prosthetic Robotic Hands Based

on a Multi-Layer Deformable Design

Li Tian , Jianmin Zheng , Yiyu Cai , Muhammad Faaiz Khan Bin Abdul Halil ,
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Nadia Magnenat Thalmann , Daniel Thalmann and Hanhui Li *
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1 Institute for Media Innovation, Nanyang Technological University, Singapore
2 School of Computer Science and Engineering, Nanyang Technology University, Singapore
3 School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore
4 MIRALab, University of Geneva, Switzerland
5 École Polytechnique Fédérale de Lausanne, Switzerland
6 School of Electrical and Electronic Engineering, Nanyang Technology University, Singapore
Abstract: Current research of designing prosthetic robotic hands mainly focuses on improving their functionality by devising
new mechanical structures and actuation systems. Most of existing work relies on a single structure/system (e.g., bone-only
or tissue-only) and ignores the fact that the human hand is composed of multiple functional structures (e.g., skin, bones,
muscles, and tendons). This may increase the difficulty of the design process and lower the flexibility of the fabricated hand.
To tackle this problem, this paper proposes a three-dimensional (3D) printable multi-layer design that models the hand with
the layers of skin, tissues, and bones. The proposed design first obtains the 3D surface model of a target hand via 3D scanning,
and then generates the 3D bone models from the surface model based on a fast template matching method. To overcome
the disadvantage of the rigid bone layer in deformation, the tissue layer is introduced and represented by a concentric tube-
based structure, of which the deformability can be explicitly controlled by a parameter. The experimental results show that
the proposed design outperforms previous designs remarkably. With the proposed design, prosthetic robotic hands can be
produced quickly with low cost and be customizable and deformable.
Keywords: Prosthetic hand; Soft materials; 3D printing

*Correspondence to: Hanhui Li, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore;
hanhui.li@ntu.edu.sg

Received: July 13, 2021; Accepted: August 20, 2021; Published Online: September 28, 2021
(This article belongs to the Special Section: 3D Printing and Bioprinting for the Future of Healthcare)

Citation: Tian L, Zheng J, Cai Y, et al., 2022, Fast 3D Modeling of Prosthetic Robotic Hands Based on A Multi-Layer Deformable Design. Int
J Bioprint, 8(1):406. http:// doi.org/10.18063/ijb.v8i1.406
1. Introduction soft materials, and simplifying the hand designs are
emerging trends of research in recent years .
[10]
Designing robotic hands that mimic the general aspects From the perspective of human hand anatomy, most
of the human hand is one of the most challenging current robotic hands can be roughly divided into two
problems in robotics due to the sophisticated structure groups: (i) rigid-body robotic hands (e.g., bone based) [3,11-15]
and functionality of the human hand . Ever since the that consist of rigid, individual structures replicating
[1]
early dexterous Stanford/JPL hand was invented , there phalanges and joints, such as Shadow Dexterous Hand
[2]
[3]
have been extensive inspiring advances in this area [3-9] . and ACB hand , and (ii) soft, tissue-like hands [5,16] that
[15]
For example, Hughes et al. proposed the conditional are built using soft materials and actuators, among which
[8]
model that exploits the anisotropic mechanical stiffness RBO hand is the typical example . These two types of
[5]
to achieve passivity-based dynamic interactions. robotic hands have their own advantages: rigid-body
Particularly, replacing rigid mechanical structures with hands are reliable, sturdy, and better reflect the movement
© 2021 Author(s). This is an Open Access article distributed under the terms of the Creative Commons Attribution License, permitting distribution and
reproduction in any medium, provided the original work is properly cited.
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