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Comparison of point foot, collisional and smooth rolling contact models on the bifurcations and stability of bipedal walking / William Charles; Pooya Mahmoodi; Rajesh Ransing; Igor Sazonov; Michael Friswell

European Journal of Computational Mechanics, Volume: 25, Issue: 3, Pages: 273 - 293

Swansea University Author: Rajesh, Ransing

Abstract

Traditional biped walkers based on passive dynamic walking usually have flat or circular feet. Thisfoot contact may be modelled with an eective rocker - represented as a roll-over shape - to describethe function of the knee-ankle-foot complex in human ambulation. Mahmoodi et al. has representedthis...

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Published in: European Journal of Computational Mechanics
ISSN: 1779-7179
Published: 2016
Online Access: Check full text

URI: https://cronfa.swan.ac.uk/Record/cronfa31527
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Abstract: Traditional biped walkers based on passive dynamic walking usually have flat or circular feet. Thisfoot contact may be modelled with an eective rocker - represented as a roll-over shape - to describethe function of the knee-ankle-foot complex in human ambulation. Mahmoodi et al. has representedthis roll-over shape as a polygon with a discretized set of collisions. In this paper point foot, collisionaland smooth rolling contact models are compared. An approach based on the Lagrangian mechanicsare used to formulate the equations for the swing phase that conserves mechanical energy. Qualitativeinsight can be gained by studying the bifurcation diagrams of gait descriptors such as average velocity,step period, mechanical energy and inter-leg angle for dierent gain and length values for the feet,as well as dierent mass and length ratios. The results from the three approaches are compared anddiscussed. In the case of a rolling disk, the collisional contact model gives a negligible energy loss;incorporated into the double inverted pendulum system, however, reveals much greater errors. Thisresearch is not only useful for understanding the stability of bipedal walking, but also for the designof rehabilitative devices such as prosthetic feet and orthoses.
Keywords: Passive walking; Gait analysis; Roll-over shape; Prosthetic foot; Foot contact; Bifurcation diagrams; Basin of attraction
College: College of Engineering
Issue: 3
Start Page: 273
End Page: 293