Estimating System State During Human Walking with a Powered Ankle-Foot Orthosis

dc.contributor.authorLi, David Y.
dc.contributor.authorBecker, Aaron T.
dc.contributor.authorShorter, Kenneth A.
dc.contributor.authorBretl, Timothy W.
dc.contributor.authorHsiao-Wecksler, Elizabeth T.
dc.date.accessioned2019-10-01T15:39:40Z
dc.date.available2019-10-01T15:39:40Z
dc.date.issued8/15/2011
dc.description.abstractThis paper presents a state estimator that reliably detects gait events during human walking with a portable powered ankle-foot orthosis (AFO), based only on measurements of the ankle angle and of contact forces at the toe and heel. Effective control of the AFO critically depends on detecting these gait events. A common approach detects gait events simply by checking if each measurement exceeds a given threshold. Our approach uses cross correlation between a window of past measurements and a learned model to estimate the configuration of the human walker, and detects gait events based on this estimate. We tested our approach in experiments with five healthy subjects and with one subject that had neuromuscular impairment. Using motion capture data for reference, we compared our approach to one based on thresholding and to another common one based on k -nearest neighbors. The results showed that our approach reduced the RMS error by up to 40% for the impaired subject and up to 49% for the healthy subjects. Moreover, our approach was robust to perturbations due to changes in walking speed and to control actuation.
dc.identifier10.1109/TMECH.2011.2161769
dc.identifier.citationCopyright 2011 IEEE/ASME Transactions on Mechatronics. This is a post-print version of a published paper that is available at: https://ieeexplore.ieee.org/abstract/document/5985534 Recommended citation: Li, David Yifan, Aaron Becker, Kenneth Alex Shorter, Timothy Bretl, and Elizabeth T. Hsiao-Wecksler. "Estimating system state during human walking with a powered ankle-foot orthosis." IEEE/ASME Transactions on Mechatronics 16, no. 5 (2011): 835-844. DOI: 10.1109/TMECH.2011.2161769 This item has been deposited in accordance with publisher copyright and licensing terms and with the author’s permission.
dc.identifier.urihttps://hdl.handle.net/10657/4904
dc.language.isoen_US
dc.publisherIEEE/ASME Transactions on Mechatronics
dc.subjectSensors
dc.subjectLegged locomotion
dc.subjectTorque
dc.subjectData models
dc.subjectState estimation
dc.subjectEvent detection
dc.titleEstimating System State During Human Walking with a Powered Ankle-Foot Orthosis
dc.typeArticle

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