Biologically inspired design and development of a variable stiffness powered ankle-foot prosthesis

Dobson, AA; Wei, G; Ren, L

Abstract

Recent advancements in powered lower limb prostheses have appeased several difficulties faced by lower limb amputees by using a Series-Elastic Actuator (SEA) to provide powered sagittal plane flexion. Unfortunately, these devices are currently unable to provide both powered sagittal plane flexion and 2-DOF at the ankle, removing the ankle’s capacity to invert/evert, thus severely limiting terrain adaption capabilities and user comfort. The developed 2-DOF ankle system in this paper allows both powered flexion in the sagittal plane and passive rotation in the frontal plane; a SEA emulates the biomechanics of the gastrocnemius and Achilles tendon for flexion, while a novel universal-joint system provides the 2-DOF. Several studies were undertaken to thoroughly characterize the capabilities of the device. Under both level and sloped-ground conditions, ankle torque and kinematic data was obtained by using force-plates and a motion capture system. The device was found to be fully capable of providing powered sagittal plane motion and torque very close to that of a biological ankle, while simultaneously being able to adapt to sloped terrain by undergoing frontal plane motion, thus providing 2-DOF at the ankle. These findings demonstrate that the device presented in this paper poses radical improvements to powered PAFD design.

Citation

Dobson, A., Wei, G., & Ren, L. (2019). Biologically inspired design and development of a variable stiffness powered ankle-foot prosthesis. Journal of Mechanisms and Robotics, 11(4), https://doi.org/10.1115/1.4043603

• Journal Article Type: Article
• Acceptance Date: Apr 3, 2019
• Online Publication Date: Apr 24, 2019
• Publication Date: Apr 24, 2019
• Deposit Date: Apr 4, 2019
• Publicly Available Date: Apr 24, 2020
• Journal: Journal of Mechanisms and Robotics
• Print ISSN: 1942-4302
• Electronic ISSN: 1942-4310
• Publisher: American Society of Mechanical Engineers
• Volume: 11
• Issue: 4
• DOI: https://doi.org/10.1115/1.4043603
• Publisher URL: https://doi.org/10.1115/1.4043603
• Related Public URLs: http://mechanismsrobotics.asmedigitalcollection.asme.org/journal.aspx