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Optimisation of bipedal walking motion with unbalanced masses. / Pooya Mahmoodi
Swansea University Author: Pooya Mahmoodi
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Abstract
Commercial prosthetic feet weigh about 25% of their equivalent physiological counterparts. The human body has a tendency to overcome the walking asymmetry resulting from the mass imbalance by exerting more energy. A two link passive walking kinematic model, with realistic masses for prosthetic, phys...
Published: |
2014
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Institution: | Swansea University |
Degree level: | Doctoral |
Degree name: | Ph.D |
URI: | https://cronfa.swan.ac.uk/Record/cronfa42489 |
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2018-08-02T16:24:29.4314045 v2 42489 2018-08-02 Optimisation of bipedal walking motion with unbalanced masses. e44c5ce3956d6738dbfcdc0cb3bd40a0 NULL Pooya Mahmoodi Pooya Mahmoodi true true 2018-08-02 Commercial prosthetic feet weigh about 25% of their equivalent physiological counterparts. The human body has a tendency to overcome the walking asymmetry resulting from the mass imbalance by exerting more energy. A two link passive walking kinematic model, with realistic masses for prosthetic, physiological legs and upper body, has been proposed to study the gait pattern with unbalanced leg masses. The 'heel to toe' rolling contact has significant influence on the dynamics of biped models. This contact is modelled using the roll-over shape defined in the local co-ordinate system aligned with the stance leg. The effect of rollover shape curvature and arc length has been studied on various gait descriptors such as average velocity, step period, inter leg angle (and hence step length), mechanical energy. The bifurcation diagrams have been plotted for point feet and different gain values. The insight gained by studying the bifurcation diagrams for different gain and length values is not only useful in understanding the stability of the biped walking process but also in the design of prosthetic feet. It is proposed that the stiffness and energy release mechanisms of prosthetic feet be designed to satisfy amputee's natural gait characteristics that are defined by an effective roll-over shape and corresponding ground reaction force combinations. Each point on the roll-over shape is mapped with a ground reaction force corresponding to its time step. The resulting discrete set of ground reaction force components are applied to the prosthetic foot sole and its stiffness profile is optimised to produce a desired deflection as given by the corresponding point on the roll-over shape. It is shown that the proposed methodology is able to provide valuable insights in the guidelines for selection of materials for a multi-material prosthetic foot. E-Thesis Biomechanics. 31 12 2014 2014-12-31 COLLEGE NANME Engineering COLLEGE CODE Swansea University Doctoral Ph.D 2018-08-02T16:24:29.4314045 2018-08-02T16:24:29.4314045 Faculty of Science and Engineering School of Engineering and Applied Sciences - Uncategorised Pooya Mahmoodi NULL 1 0042489-02082018162458.pdf 10801719.pdf 2018-08-02T16:24:58.5270000 Output 18676125 application/pdf E-Thesis true 2018-08-02T16:24:58.5270000 false |
title |
Optimisation of bipedal walking motion with unbalanced masses. |
spellingShingle |
Optimisation of bipedal walking motion with unbalanced masses. Pooya Mahmoodi |
title_short |
Optimisation of bipedal walking motion with unbalanced masses. |
title_full |
Optimisation of bipedal walking motion with unbalanced masses. |
title_fullStr |
Optimisation of bipedal walking motion with unbalanced masses. |
title_full_unstemmed |
Optimisation of bipedal walking motion with unbalanced masses. |
title_sort |
Optimisation of bipedal walking motion with unbalanced masses. |
author_id_str_mv |
e44c5ce3956d6738dbfcdc0cb3bd40a0 |
author_id_fullname_str_mv |
e44c5ce3956d6738dbfcdc0cb3bd40a0_***_Pooya Mahmoodi |
author |
Pooya Mahmoodi |
author2 |
Pooya Mahmoodi |
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E-Thesis |
publishDate |
2014 |
institution |
Swansea University |
college_str |
Faculty of Science and Engineering |
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facultyofscienceandengineering |
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Faculty of Science and Engineering |
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facultyofscienceandengineering |
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Faculty of Science and Engineering |
department_str |
School of Engineering and Applied Sciences - Uncategorised{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Engineering and Applied Sciences - Uncategorised |
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description |
Commercial prosthetic feet weigh about 25% of their equivalent physiological counterparts. The human body has a tendency to overcome the walking asymmetry resulting from the mass imbalance by exerting more energy. A two link passive walking kinematic model, with realistic masses for prosthetic, physiological legs and upper body, has been proposed to study the gait pattern with unbalanced leg masses. The 'heel to toe' rolling contact has significant influence on the dynamics of biped models. This contact is modelled using the roll-over shape defined in the local co-ordinate system aligned with the stance leg. The effect of rollover shape curvature and arc length has been studied on various gait descriptors such as average velocity, step period, inter leg angle (and hence step length), mechanical energy. The bifurcation diagrams have been plotted for point feet and different gain values. The insight gained by studying the bifurcation diagrams for different gain and length values is not only useful in understanding the stability of the biped walking process but also in the design of prosthetic feet. It is proposed that the stiffness and energy release mechanisms of prosthetic feet be designed to satisfy amputee's natural gait characteristics that are defined by an effective roll-over shape and corresponding ground reaction force combinations. Each point on the roll-over shape is mapped with a ground reaction force corresponding to its time step. The resulting discrete set of ground reaction force components are applied to the prosthetic foot sole and its stiffness profile is optimised to produce a desired deflection as given by the corresponding point on the roll-over shape. It is shown that the proposed methodology is able to provide valuable insights in the guidelines for selection of materials for a multi-material prosthetic foot. |
published_date |
2014-12-31T03:53:04Z |
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1763752630557868032 |
score |
11.012678 |