Simulated performance of an energy storage and return prosthetic ankle based on cams and miniature hydraulics

Pace, A; Gardiner, JD; Kenney, LPJ; Howard, D

Abstract

Prosthetic feet are limited in their ability to mimic the energy-recycling behaviour of an intact ankle, negatively affecting lower-limb amputees’ gait in terms of metabolic cost and walking speed. To overcome these weaknesses, a novel prosthetic ankle based on hydraulics is described here. The ankle joint drives two cams, which in turn drive two hydraulic rams. One cam-ram system captures the negative work done from foot-flat until maximum dorsiflexion, by pumping oil into an accumulator, while the other returns positive work during push-off providing forward propulsion through fluid flowing from the accumulator to the ram. Simulation results are promising: of the total negative work done by the prosthetic ankle over the gait cycle (i.e., the maximum amount of energy available to be stored), 78% is returned, mainly during push-off; 14% is carried forward for future gait cycles; and 8% is lost. The estimated prosthesis height and mass are approximately 26.5cm and 2.3kg. Nonetheless, further work is necessary to realise a prototype for bench and in-vivo testing. By mimicking intact ankle torque and efficiently storing and returning energy at the ankle joint, this new design may contribute to reducing amputees’ metabolic cost of walking.

Citation

Pace, A., Gardiner, J., Kenney, L., & Howard, D. (2022). Simulated performance of an energy storage and return prosthetic ankle based on cams and miniature hydraulics. IEEE Transactions on Medical Robotics and Bionics, https://doi.org/10.1109/TMRB.2022.3146628

• Journal Article Type: Article
• Acceptance Date: Nov 28, 2021
• Online Publication Date: Jan 26, 2022
• Publication Date: Jan 26, 2022
• Deposit Date: Jan 31, 2022
• Publicly Available Date: Jan 31, 2022
• Journal: IEEE Transactions on Medical Robotics and Bionics
• Print ISSN: 2576-3202
• Publisher: Institute of Electrical and Electronics Engineers
• DOI: https://doi.org/10.1109/TMRB.2022.3146628
• Publisher URL: https://doi.org/10.1109/TMRB.2022.3146628
• Related Public URLs: https://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=8253409
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