Development and Evaluation of an Energy-Removing Lower-Limb Exoskeleton for Human Gait Assistance
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Authors
Shepertycky, Michael
Date
Type
thesis
Language
eng
Keyword
Exoskeleton , Biomechanics , Gait , Energy-removing lower-limb exoskeleton , Energetics , Metabolic cost , Biomechanical energy harvesting , Mechanical engineering , Biomedical engineering
Alternative Title
Abstract
Walking is a metabolically demanding activity. Scientists have developed two general approaches to reducing the metabolic cost of walking using exoskeletons: 1) adding energy to the human-device system to assist concentric muscle contractions, and 2) transferring energy from one gait phase to another (or from one joint to another) to assist isometric muscle contractions. Despite several exoskeletons' success in reducing the metabolic cost of walking, the practical application of these devices is limited by their short operational lifespans and poor adaptive control.
This thesis outlines the design and evaluation of a novel lower limb exoskeleton capable of reducing the metabolic cost of walking. This device applies a novel approach to user assistance—removing energy to assist the hamstrings’ eccentric contractions during the swing period. Although devices that assist with concentric and isometric contractions have yielded larger metabolic cost reductions, we show that assisting with eccentric contractions can significantly reduce metabolic cost with the concurrent benefit of electricity production. This capacity to convert removed energy into electricity suggests that devices employing this assistive technique can be self-powering, extending their operational lifespan and enabling adaptive control. We also provide direct evidence that the assistance profile's timing and magnitude are important factors in reducing the metabolic cost of walking. We demonstrate that applying a moderate level of assistance during the terminal swing phase results in the greatest metabolic cost reduction under the present experimental conditions.
The present work advances our understanding of the complex human-device interactions that occur during walking with an exoskeleton, as well as the general principles governing human gait. In addition to elucidating the energetics and biomechanics of walking, the present work provides insights into the design, control, and evaluation of devices that remove energy for their users during walking. Based on our findings, we recommend that future lower-limb exoskeletons employ muscle-specific parameters and profiles to provide the largest amount of metabolic assistance.
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Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada
ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.
Attribution-NonCommercial-NoDerivs 3.0 United States
ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.
Attribution-NonCommercial-NoDerivs 3.0 United States