Journal of Rehabilitation Research & Development (JRRD)

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Volume 50 Number 1, 2013
   Pages 43 — 52

Abstract — Mechanical and biomechanical analysis of a linear piston design for angular-velocity-based orthotic control

Edward D. Lemaire, PhD;1–2* Reza Samadi, MASc;1 Louis Goudreau, PEng;1 Jonathan Kofman, PhD, PEng3
1Ottawa Hospital Research Institute, The Ottawa Hospital Rehabilitation Centre, Ottawa, Canada; 2Faculty of Medicine, University of Ottawa, Ottawa, Canada; 3Department of Systems Design Engineering, University of Waterloo, Waterloo, Canada

Abstract — A linear piston hydraulic angular-velocity-based control knee joint was designed for people with knee-extensor weakness to engage knee-flexion resistance when knee-flexion angular velocity reaches a preset threshold, such as during a stumble, but to otherwise allow free knee motion. During mechanical testing at the lowest angular-velocity threshold, the device engaged within 2 degrees knee flexion and resisted moment loads of over 150 Nm. The device completed 400,000 loading cycles without mechanical failure or wear that would affect function. Gait patterns of nondisabled participants were similar to normal at walking speeds that produced below-threshold knee angular velocities. Fast walking speeds, employed purposely to attain the angular-velocity threshold and cause knee-flexion resistance, reduced maximum knee flexion by approximately 25 degrees but did not lead to unsafe gait patterns in foot ground clearance during swing. In knee collapse tests, the device successfully engaged knee-flexion resistance and stopped knee flexion with peak knee moments of up to 235.6 Nm. The outcomes from this study support the potential for the linear piston hydraulic knee joint in knee and knee-ankle-foot orthoses for people with lower-limb weakness.

Key words: angular velocity, angular-velocity-based orthosis, cyclic testing, gait, knee-ankle-foot orthosis, mechanical testing, orthosis, Ottawalk-Speed, stance control, stance-control orthosis.

View HTML  ¦  View PDF  ¦  Contents Vol. 50, No. 1
This article and any supplementary material should be cited as follows:
Lemaire ED, Samadi R, Goudreau L, Kofman J. Mechanical and biomechanical analysis of a linear piston design for angular-velocity-based orthotic control. J Rehabil Res Dev. 2013;50(1):43–52.
ResearcherID: Edward D. Lemaire, PhD: B-1502-2012

Last Reviewed or Updated  Monday, March 11, 2013 2:09 PM

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