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Investigation of an EMG referenced control channel for grasp force supplementation Forrest, Gregory G.
Abstract
This work investigates the potential of using an air-muscle actuated orthosis controlled by an electromyographic (EMG) signal to reliably supplement the grasping force of the hand, thereby allowing the user to reduce the muscle activation required for a power-grasping task. In particular, the study reported herein tested the hypotheses that subjects could stably handle objects and learn to reduce both their grip force and muscle activation levels with force supplementation. In this study, a surface-mounted EMG sensor on the flexor digitorum provides the input to a proportional-integral-derivative controller governing the force generated by the orthosis. Although this approach presumes that the human motor system will stably adapt to the orthotic system, we designed the system to operate in an intuitive and predictable manner. Nine subjects performed a sequence of unassisted and assisted lifts of a weighted and instrumented cylinder. When using the orthotic system to lift the cylinder, subjects reliably reduced their mean grip force and mean percent maximum voluntary contraction (%MVC) (p<0.01). The grip force applied to the cylinder was reduced for seven of the nine subjects (p<0.01) and the %MVC was reduced for five of the nine subjects (p<0.01). None of the subjects exhibited any instability or reported any difficulties when using the orthosis. On average, the subjects reduced their %MVC and grasp force by 31% and 56% respectively.
Item Metadata
Title |
Investigation of an EMG referenced control channel for grasp force supplementation
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
2004
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Description |
This work investigates the potential of using an air-muscle actuated orthosis controlled by an
electromyographic (EMG) signal to reliably supplement the grasping force of the hand, thereby
allowing the user to reduce the muscle activation required for a power-grasping task. In
particular, the study reported herein tested the hypotheses that subjects could stably handle
objects and learn to reduce both their grip force and muscle activation levels with force
supplementation. In this study, a surface-mounted EMG sensor on the flexor digitorum provides
the input to a proportional-integral-derivative controller governing the force generated by the
orthosis. Although this approach presumes that the human motor system will stably adapt to the
orthotic system, we designed the system to operate in an intuitive and predictable manner. Nine
subjects performed a sequence of unassisted and assisted lifts of a weighted and instrumented
cylinder. When using the orthotic system to lift the cylinder, subjects reliably reduced their mean
grip force and mean percent maximum voluntary contraction (%MVC) (p<0.01). The grip force
applied to the cylinder was reduced for seven of the nine subjects (p<0.01) and the %MVC was
reduced for five of the nine subjects (p<0.01). None of the subjects exhibited any instability or
reported any difficulties when using the orthosis. On average, the subjects reduced their %MVC
and grasp force by 31% and 56% respectively.
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Extent |
20776378 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-11-21
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0080729
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
2004-11
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.