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dc.contributor.authorShannon, Colleen Elizabethen_US
dc.date.accessioned2014-03-14T20:38:54Z
dc.date.available2014-03-14T20:38:54Z
dc.date.issued2003-05-19en_US
dc.identifier.otheretd-05292003-165003en_US
dc.identifier.urihttp://hdl.handle.net/10919/33322
dc.description.abstractRecurrent Gait of Anthropomorphic, Bipedal Walkers Colleen E. Shannon (ABSTRACT) This thesis explores the dynamics of two bipedal, passive-walker models that are free to move in a three-dimensional environment. Specifically, two rigid-bodied walkers that can sustain anthropomorphic gait down an inclined plane with gravity being the only source of energy were studied using standard dynamical systems methods. This includes calculating the stability of periodic orbits and varying the system parameter to create bifurcation diagrams and to address the persistence of a periodic solution under specific parameter variations. These periodic orbits are found by implementing the Newton-Raphson root solving scheme. The dynamical systems associated with these periodic orbits are not completely smooth. Instead, they include discontinuities, such as those produced due to forces at foot contact points and during knee hyper-extension. These discontinuities are addressed in the stability calculations through appropriate discontinuity mappings. The difference between the two walker models is the number of degrees of freedom (DOF) at the hip. Humans possess three DOF at each hip joint, one DOF at each knee joint, and at least two DOF at each ankle joint. The first walker model studied had revolute joints at the hips and knees and completely locked ankles. To make the walking motion more anthropomorphic, additional degrees of freedom were added to the hip. Specifically, the second walker model has ball joints at the hips. Two control algorithms are used for controlling the local stability of periodic motions for both walker models. The methods, reference and delay feedback control, rely on the presence of discontinuities in the system. Moreover, it is possible to predict the effects of the control strategy based entirely on information from the uncontrolled system. Control is applied to both passive walker models to try and stabilize an unstable periodic gait by making small, discrete, changes in the foot orientation during gait. Results show that both methods are successful in stabilizing an unstable walking motion for a 3D model with one DOF in each hip and to reduce the instability of the walking motions for the model having more mobility in the hip joints.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartcshannon2.pdfen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectFeedback Controlen_US
dc.subjectDynamical Systemsen_US
dc.subjectHuman Walkingen_US
dc.subjectPassive Walkeren_US
dc.subjectLocomotionen_US
dc.titleRecurrent Gait of Anthropomorphic, Bipedal Walkersen_US
dc.typeThesisen_US
dc.contributor.departmentMechanical Engineeringen_US
dc.description.degreeMaster of Scienceen_US
thesis.degree.nameMaster of Scienceen_US
thesis.degree.levelmastersen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineMechanical Engineeringen_US
dc.contributor.committeechairDankowicz, Harry J.en_US
dc.contributor.committeememberReinholtz, Charles F.en_US
dc.contributor.committeememberRobertshaw, Harry H.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-05292003-165003/en_US
dc.date.sdate2003-05-29en_US
dc.date.rdate2003-07-10
dc.date.adate2003-07-10en_US


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