A Wearable Soft Fabric Sleeve for Upper Limb Augmentation

Trung Thien Hoang; Luke Sy; Mattia Bussu; Mai Thanh Thai; Harrison Low; Phuoc Thien Phan; James Davies; Chi Cong Nguyen; Nigel H. Lovell; Thanh Nho Do

doi:10.3390/s21227638

Sensors (Nov 2021)

A Wearable Soft Fabric Sleeve for Upper Limb Augmentation

Trung Thien Hoang,
Luke Sy,
Mattia Bussu,
Mai Thanh Thai,
Harrison Low,
Phuoc Thien Phan,
James Davies,
Chi Cong Nguyen,
Nigel H. Lovell,
Thanh Nho Do

Affiliations

Trung Thien Hoang: Graduate School of Biomedical Engineering, Faculty of Engineering, University of New South Wales, Sydney 2052, Australia
Luke Sy: Graduate School of Biomedical Engineering, Faculty of Engineering, University of New South Wales, Sydney 2052, Australia
Mattia Bussu: Institute of Robotics and Intelligent Systems, Eidgenössische Technische Hochschule Zürich, 8092 Zurich, Switzerland
Mai Thanh Thai: Graduate School of Biomedical Engineering, Faculty of Engineering, University of New South Wales, Sydney 2052, Australia
Harrison Low: Graduate School of Biomedical Engineering, Faculty of Engineering, University of New South Wales, Sydney 2052, Australia
Phuoc Thien Phan: Graduate School of Biomedical Engineering, Faculty of Engineering, University of New South Wales, Sydney 2052, Australia
James Davies: Graduate School of Biomedical Engineering, Faculty of Engineering, University of New South Wales, Sydney 2052, Australia
Chi Cong Nguyen: Graduate School of Biomedical Engineering, Faculty of Engineering, University of New South Wales, Sydney 2052, Australia
Nigel H. Lovell: Graduate School of Biomedical Engineering, Faculty of Engineering, University of New South Wales, Sydney 2052, Australia
Thanh Nho Do: Graduate School of Biomedical Engineering, Faculty of Engineering, University of New South Wales, Sydney 2052, Australia

DOI: https://doi.org/10.3390/s21227638
Journal volume & issue: Vol. 21, no. 22
p. 7638

Abstract

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Soft actuators (SAs) have been used in many compliant robotic structure and wearable devices, due to their safe interaction with the wearers. Despite advances, the capability of current SAs is limited by scalability, high hysteresis, and slow responses. In this paper, a new class of soft, scalable, and high-aspect ratio fiber-reinforced hydraulic SAs is introduced. The new SA uses a simple fabrication process of insertion where a hollow elastic rubber tube is directly inserted into a constrained hollow coil, eliminating the need for the manual wrapping of an inextensible fiber around a long elastic structure. To provide high adaptation to the user skin for wearable applications, the new SAs are integrated into flexible fabrics to form a wearable fabric sleeve. To monitor the SA elongation, a soft liquid metal-based fabric piezoresistive sensor is also developed. To capture the nonlinear hysteresis of the SA, a novel asymmetric hysteresis model which only requires five model parameters in its structure is developed and experimentally validated. The new SAs-driven wearable robotic sleeve is scalable, highly flexible, and lightweight. It can also produce a large amount of force of around 23 N per muscle at around 30% elongation, to provide useful assistance to the human upper limbs. Experimental results show that the soft fabric sleeve can augment a user’s performance when working against a load, evidenced by a significant reduction on the muscular effort, as monitored by electromyogram (EMG) signals. The performance of the developed SAs, soft fabric sleeve, soft liquid metal fabric sensor, and nonlinear hysteresis model reveal that they can effectively modulate the level of assistance for the wearer. The new technologies obtained from this work can be potentially implemented in emerging assistive applications, such as rehabilitation, defense, and industry.

Published in Sensors

ISSN: 1424-8220 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Technology: Chemical technology
Website: http://www.mdpi.com/journal/sensors

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