Constraining the Body for Better Force-Tracking Analysis
| dc.contributor.author | Thompson, Megan Elizabeth | |
| dc.date.accessioned | 2008-03-04T16:59:42Z | |
| dc.date.available | 2013-03-04T07:22:41Z | |
| dc.date.issued | 2008-03-04T16:59:42Z | |
| dc.description.abstract | My work has two goals: to develop a method capable of comfortably isolating a single group of muscles to improve in vivo human muscle testing and to investigate how well humans can track target force profiles. I designed, built, and tested a system for isolating leg-extensor muscles (muscles that lift the lower leg) and for measuring knee extension forces during an interactive tracking experiment featuring computer feedback. The chair was designed to isolate the leg-extensor muscle and to eliminate movement by forming rigid connections to the body. When properly constrained in the chair, the maximum movement observed during "fixed" leg angle experiments was a leg rotation of ~1 degree. In the first force-tracking experiments, the test subject tracked a periodic target force function at a fixed leg angle. In the second experiments, the subject attempted to match a constant, ramp, or sine wave force profile as her leg angle was being oscillated from 90 degrees to 120 degrees by a motor. Target wave frequencies for the fixed-angle experiments were 0.10 Hz, 0.25 Hz, 0.50 Hz, 1.00 Hz, and 2.00 Hz; for variable-angle experiments: 0.25 Hz, 0.50 Hz, or 1.00 Hz. Among fixed-angle tests, the lowest RMS error was 4.12%, and the highest was 23.86%. The best variable angle result, obtained while tracking a constant force, was 9.06%. Error was considerably lower for fixed-angle experiments than it was for variable-angle experiments--the lowest measured error in variable-angle tests was similar to the highest error in fixed-angle tests. Results generally improved with increasing target force magnitude and worsened with increasing target and forcing frequency. For fixed-angle tests, conducting additional tests improved accuracy but not precision; the opposite was true for variable-angle tests. | en_US |
| dc.identifier.uri | https://hdl.handle.net/1813/10135 | |
| dc.language.iso | en_US | en_US |
| dc.relation.isformatof | bibid: 6397092 | |
| dc.subject | mechanical engineering | en_US |
| dc.subject | biomechanics | en_US |
| dc.subject | force-tracking | en_US |
| dc.subject | limb constraints | en_US |
| dc.title | Constraining the Body for Better Force-Tracking Analysis | en_US |
| dc.type | dissertation or thesis | en_US |
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