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Transparent control in overground walking exoskeleton reveals interesting changing in subject's stepping frequency

Rafhael M. Andrade, Stefano Sapienza, Abolfazl Mohebbi, Eric Fabara and Paolo Bonato

Article (2024)

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Lower-limb gait training (GT) exoskeletons have been successfully used in rehabilitation programs to overcome the burden of locomotor impairment. However, providing suitable net interaction torques to assist patient movements is still a challenge. Previous transparent operation approaches have been tested in treadmill-based GT exoskeletons to improve user-robot interaction. However, it is not yet clear how a transparent lower-limb GT system affects user’s gait kinematics during overground walking, which unlike treadmill-based systems, requires active participation of the subjects to maintain stability. In this study, we implemented a transparent operation strategy on the ExoRoboWalker, an overground GT exoskeleton, to investigate its effect on the user’s gait. The approach employs a feedback zero-torque controller with feedforward compensation for the exoskeleton’s dynamics and actuators’ impedance. We analyzed the data of five healthy subjects walking overground with the exoskeleton in transparent mode (ExoTransp) and non-transparent mode (ExoOff) and walking without exoskeleton (NoExo). The transparent controller reduced the user-robot interaction torque and improved the user’s gait kinematics relative to ExoOff. No significant difference in stride length is observed between ExoTransp and NoExo (p = 0.129). However, the subjects showed a significant difference in cadence between ExoTransp (50.9± 1.1 steps/min) and NoExo (93.7 ± 8.7 steps/min) (p = 0.015), but not between ExoTransp and ExoOff (p = 0.644). Results suggest that subjects wearing the exoskeleton adjust their gait as in an attention-demanding task changing the spatiotemporal gait characteristics likely to improve gait balance.

Uncontrolled Keywords

low-limb exoskeleton; gait training; transparent control; fait kinematics

Subjects: 1900 Biomedical engineering > 1900 Biomedical engineering
1900 Biomedical engineering > 1901 Biomedical technology
1900 Biomedical engineering > 1902 Biomedical materials
2100 Mechanical engineering > 2100 Mechanical engineering
Department: Department of Mechanical Engineering
Funders: Peabody Foundation, Financiadora de Estudos e Projetos, Fundação de Amparo à Pesquisa e Inovação do Espírito Santo
Grant number: Recursos do FNDCT ref 2784/20, TO: 460/2021, Project No. 2021-L7SZ4, TO 151/2021, Project No. 2021-8GJZ6, TO: 414/2022, Project No. 2022-SX1VM
PolyPublie URL: https://publications.polymtl.ca/56745/
Journal Title: IEEE Journal of Translational Engineering in Health and Medicine (vol. 12)
Publisher: IEEE
DOI: 10.1109/jtehm.2023.3323381
Official URL: https://doi.org/10.1109/jtehm.2023.3323381
Date Deposited: 23 Jan 2024 12:49
Last Modified: 20 Apr 2024 12:19
Cite in APA 7: Andrade, R. M., Sapienza, S., Mohebbi, A., Fabara, E., & Bonato, P. (2024). Transparent control in overground walking exoskeleton reveals interesting changing in subject's stepping frequency. IEEE Journal of Translational Engineering in Health and Medicine, 12, 182-193. https://doi.org/10.1109/jtehm.2023.3323381


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