Biomimetic Tendon-Based Mechanism for Finger Flexion and Extension in a Soft Hand Exoskeleton: Design and Experimental Assessment

This study proposes a bioinspired exotendon routing configuration for a tendon-based mechanism to provide finger flexion and extension that utilizes a single motor to reduce the complexity of the system. The configuration was primarily inspired by the extrinsic muscle–tendon units of the human muscu...

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Main Authors: Mohamed H. Abdelhafiz, Lotte N. S. Andreasen Struijk, Strahinja Dosen, Erika G. Spaich
Format: Article
Language:English
Published: MDPI AG 2023-02-01
Series:Sensors
Subjects:
Online Access:https://www.mdpi.com/1424-8220/23/4/2272
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author Mohamed H. Abdelhafiz
Lotte N. S. Andreasen Struijk
Strahinja Dosen
Erika G. Spaich
author_facet Mohamed H. Abdelhafiz
Lotte N. S. Andreasen Struijk
Strahinja Dosen
Erika G. Spaich
author_sort Mohamed H. Abdelhafiz
collection DOAJ
description This study proposes a bioinspired exotendon routing configuration for a tendon-based mechanism to provide finger flexion and extension that utilizes a single motor to reduce the complexity of the system. The configuration was primarily inspired by the extrinsic muscle–tendon units of the human musculoskeletal system. The function of the intrinsic muscle–tendon units was partially compensated by adding a minor modification to the configuration of the extrinsic units. The finger kinematics produced by this solution during flexion and extension were experimentally evaluated on an artificial finger and compared to that obtained using the traditional mechanism, where one exotendon was inserted at the distal phalanx. The experiments were conducted on nine healthy subjects who wore a soft exoskeleton glove equipped with the novel tendon mechanism. Contrary to the traditional approach, the proposed mechanism successfully prevented the hyperextension of the distal interphalangeal (DIP) and the metacarpophalangeal (MCP) joints. During flexion, the DIP joint angles produced by the novel mechanism were smaller than the angles generated by the traditional approach for the same proximal interphalangeal (PIP) joint angles. This provided a flexion trajectory closer to the voluntary flexion motion and avoided straining the interphalangeal coupling between the DIP and PIP joints. Finally, the proposed solution generated similar trajectories when applied to a stiff artificial finger (simulating spasticity). The results, therefore, demonstrate that the proposed approach is indeed an effective solution for the envisioned soft hand exoskeleton system.
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spelling doaj.art-b480a059cf8f41899dd44a13f749a20c2023-11-16T23:12:37ZengMDPI AGSensors1424-82202023-02-01234227210.3390/s23042272Biomimetic Tendon-Based Mechanism for Finger Flexion and Extension in a Soft Hand Exoskeleton: Design and Experimental AssessmentMohamed H. Abdelhafiz0Lotte N. S. Andreasen Struijk1Strahinja Dosen2Erika G. Spaich3Neurorehabilitation Systems Group, Department of Health Science and Technology, Aalborg University, 9260 Gistrup, DenmarkNeurorehabilitation Robotics and Engineering Group, Center for Rehabilitation Robotics, Department of Health Science and Technology, Aalborg University, 9260 Gistrup, DenmarkNeurorehabilitation Systems Group, Department of Health Science and Technology, Aalborg University, 9260 Gistrup, DenmarkNeurorehabilitation Systems Group, Department of Health Science and Technology, Aalborg University, 9260 Gistrup, DenmarkThis study proposes a bioinspired exotendon routing configuration for a tendon-based mechanism to provide finger flexion and extension that utilizes a single motor to reduce the complexity of the system. The configuration was primarily inspired by the extrinsic muscle–tendon units of the human musculoskeletal system. The function of the intrinsic muscle–tendon units was partially compensated by adding a minor modification to the configuration of the extrinsic units. The finger kinematics produced by this solution during flexion and extension were experimentally evaluated on an artificial finger and compared to that obtained using the traditional mechanism, where one exotendon was inserted at the distal phalanx. The experiments were conducted on nine healthy subjects who wore a soft exoskeleton glove equipped with the novel tendon mechanism. Contrary to the traditional approach, the proposed mechanism successfully prevented the hyperextension of the distal interphalangeal (DIP) and the metacarpophalangeal (MCP) joints. During flexion, the DIP joint angles produced by the novel mechanism were smaller than the angles generated by the traditional approach for the same proximal interphalangeal (PIP) joint angles. This provided a flexion trajectory closer to the voluntary flexion motion and avoided straining the interphalangeal coupling between the DIP and PIP joints. Finally, the proposed solution generated similar trajectories when applied to a stiff artificial finger (simulating spasticity). The results, therefore, demonstrate that the proposed approach is indeed an effective solution for the envisioned soft hand exoskeleton system.https://www.mdpi.com/1424-8220/23/4/2272hand exoskeletonassistive devicesrehabilitation devicestendon-based systems
spellingShingle Mohamed H. Abdelhafiz
Lotte N. S. Andreasen Struijk
Strahinja Dosen
Erika G. Spaich
Biomimetic Tendon-Based Mechanism for Finger Flexion and Extension in a Soft Hand Exoskeleton: Design and Experimental Assessment
Sensors
hand exoskeleton
assistive devices
rehabilitation devices
tendon-based systems
title Biomimetic Tendon-Based Mechanism for Finger Flexion and Extension in a Soft Hand Exoskeleton: Design and Experimental Assessment
title_full Biomimetic Tendon-Based Mechanism for Finger Flexion and Extension in a Soft Hand Exoskeleton: Design and Experimental Assessment
title_fullStr Biomimetic Tendon-Based Mechanism for Finger Flexion and Extension in a Soft Hand Exoskeleton: Design and Experimental Assessment
title_full_unstemmed Biomimetic Tendon-Based Mechanism for Finger Flexion and Extension in a Soft Hand Exoskeleton: Design and Experimental Assessment
title_short Biomimetic Tendon-Based Mechanism for Finger Flexion and Extension in a Soft Hand Exoskeleton: Design and Experimental Assessment
title_sort biomimetic tendon based mechanism for finger flexion and extension in a soft hand exoskeleton design and experimental assessment
topic hand exoskeleton
assistive devices
rehabilitation devices
tendon-based systems
url https://www.mdpi.com/1424-8220/23/4/2272
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AT strahinjadosen biomimetictendonbasedmechanismforfingerflexionandextensioninasofthandexoskeletondesignandexperimentalassessment
AT erikagspaich biomimetictendonbasedmechanismforfingerflexionandextensioninasofthandexoskeletondesignandexperimentalassessment