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Stabilization of Exoskeletons through Active Ankle Compensation

Gurriet, Thomas and Tucker, Maegan and Kann, Claudia and Boeris, Guilhem and Ames, Aaron D. (2019) Stabilization of Exoskeletons through Active Ankle Compensation. . (Unpublished) https://resolver.caltech.edu/CaltechAUTHORS:20200109-094832526

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Abstract

This paper presents an active stabilization method for a fully actuated lower-limb exoskeleton. The method was tested on the exoskeleton ATALANTE, which was designed and built by the French start-up company Wandercraft. The main objective of this paper is to present a practical method of realizing more robust walking on hardware through active ankle compensation. The nominal gait was generated through the hybrid zero dynamic framework. The ankles are individually controlled to establish three main directives; (1) keeping the non-stance foot parallel to the ground, (2) maintaining rigid contact between the stance foot and the ground, and (3) closing the loop on pelvis orientation to achieve better tracking. Each individual component of this method was demonstrated separately to show each component's contribution to stability. The results showed that the ankle controller was able to experimentally maintain static balance in the sagittal plane while the exoskeleton was balanced on one leg, even when disturbed. The entire ankle controller was then also demonstrated on crutch-less dynamic walking. During testing, an anatomically correct manikin was placed in the exoskeleton, in lieu of a paraplegic patient. The pitch of the pelvis of the exoskeleton-manikin system was shown to track the gait trajectory better when ankle compensation was used. Overall, active ankle compensation was demonstrated experimentally to improve balance in the sagittal plane of the exoskeleton manikin system and points to an improved practical approach for stable walking.


Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription
http://arxiv.org/abs/1909.11848arXivDiscussion Paper
ORCID:
AuthorORCID
Gurriet, Thomas0000-0002-5240-3720
Tucker, Maegan0000-0001-7363-6809
Kann, Claudia0000-0002-8318-4890
Ames, Aaron D.0000-0003-0848-3177
Additional Information:This work has been conducted under IRB No. 16-0693. The authors would like to thank the entire Wandercraft team which designed and constructed ATALANTE, and were valuable resources throughout the process. This material is based upon work supported by the NSF Graduate Research Fellowship No. DGE1745301 and NSF NRI Award No. 1724464.
Funders:
Funding AgencyGrant Number
NSF Graduate Research FellowshipDGE-1745301
NSFIIS-1724464
Record Number:CaltechAUTHORS:20200109-094832526
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20200109-094832526
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:100587
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:09 Jan 2020 18:01
Last Modified:09 Jan 2020 18:01

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