Adaptive control strategies for lower-limb exoskeletons to assist gait

Sadegh Pour Aji Bishe, Safoura (2021) Adaptive control strategies for lower-limb exoskeletons to assist gait. Doctoral thesis, Northern Arizona University.

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Abstract

Walking is a critical mode of transportation during everyday life. As a result, gait impairments can greatly affect the quality of life and personal independence of those who are affected. About 15% of people in the world have some type of physical disability, and that population is increasing rapidly. One type of disability that refers to a group of conditions that affect movement control is Cerebral Palsy (CP). Exoskeletons may help patients with CP extend their lower limb joints during walking by providing assistance and helping them walk more efficiently. Alternatively, the strategy of this assistance may vary depending on the type and severity of crouch gait. In this dissertation, we worked on four different adaptive control strategies for lower-limb exoskeletons capable of providing assistance during walking on different terrains for unimpaired individuals and individuals with CP. In the first chapter of this doctoral dissertation, we describe an adaptive control strategy development of a light-weight ankle exoskeleton based on the biomechanics of walking and how the ankle plantarflexion assistance provided based on this strategy improved the walking performance of unimpaired individuals and individuals with CP. The second chapter describes the development of a user-adaptive control strategy of a light-weight hip exoskeleton. Then the assistance provided by this control strategy is evaluated on unimpaired individuals during level and incline treadmill, as well as one individual with CP walking during level treadmill walking. In chapter three, we describe the development of a synergic ankle-knee control strategy of a lightweight unilateral ankle-knee exoskeleton based on the biomechanics of walking and validation of this control strategy on an unimpaired individual. The fourth chapter describes a bioinspired ankle joint torque simulation method based on the Winding Filament Muscle model with the potential to control the ankle joint of commercialized exoskeletons. A conclusion of these four control strategies is provided in the final chapter of this doctoral dissertation.

Item Type:	Thesis (Doctoral)
Publisher’s Statement:	© Copyright is held by the author. Digital access to this material is made possible by the Cline Library, Northern Arizona University. Further transmission, reproduction or presentation of protected items is prohibited except with permission of the author.
Keywords:	Cerebral Palsy; Control ; Exoskeleton; Walking; Adaptive control; Gait impairments
Subjects:	T Technology > TJ Mechanical engineering and machinery
MeSH Subjects:	J Technology,Industry,Agriculture > J01 Technology, Industry, and Agriculture
NAU Depositing Author Academic Status:	Student
Department/Unit:	Graduate College > Theses and Dissertations College of Engineering, Informatics, and Applied Sciences > Mechanical Engineering
Date Deposited:	04 Feb 2022 21:22
Last Modified:	28 Dec 2022 08:30
URI:	https://openknowledge.nau.edu/id/eprint/5658

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