TY - GEN
T1 - Design of a quasi-passive ankle-foot prosthesis with biomimetic, variable stiffness
AU - Shepherd, Max K.
AU - Rouse, Elliott J.
PY - 2017/7/21
Y1 - 2017/7/21
N2 - Modern passive ankle-foot prostheses do not exhibit appropriate biomechanics during walking, and are unable to adjust their mechanics for other mobility tasks, such as stair traversal or quiet standing. In this paper, we introduce a quasi-passive ankle-foot prosthesis that addresses these challenges; the ankle has a customizable, nonlinear torque-angle curve, and the overall stiffness can be varied continuously between mobility tasks. The variation in mechanics is accomplished by integrating two mechanisms: a cam-based transmission, in which rotation of the ankle joint causes deflection of a leaf spring, and an active sliding support beneath the leaf spring, which can modify the spring's effective stiffness. In addition to introducing the design, we present the mathematics to calculate the cam profile for any arbitrary torque-angle curve, and experimentally characterize the system for a desired curve based on human walking. Lastly, we demonstrate the full range of stiffness levels available and stiffness transition time.
AB - Modern passive ankle-foot prostheses do not exhibit appropriate biomechanics during walking, and are unable to adjust their mechanics for other mobility tasks, such as stair traversal or quiet standing. In this paper, we introduce a quasi-passive ankle-foot prosthesis that addresses these challenges; the ankle has a customizable, nonlinear torque-angle curve, and the overall stiffness can be varied continuously between mobility tasks. The variation in mechanics is accomplished by integrating two mechanisms: a cam-based transmission, in which rotation of the ankle joint causes deflection of a leaf spring, and an active sliding support beneath the leaf spring, which can modify the spring's effective stiffness. In addition to introducing the design, we present the mathematics to calculate the cam profile for any arbitrary torque-angle curve, and experimentally characterize the system for a desired curve based on human walking. Lastly, we demonstrate the full range of stiffness levels available and stiffness transition time.
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U2 - 10.1109/ICRA.2017.7989788
DO - 10.1109/ICRA.2017.7989788
M3 - Conference contribution
AN - SCOPUS:85028004024
T3 - Proceedings - IEEE International Conference on Robotics and Automation
SP - 6672
EP - 6678
BT - ICRA 2017 - IEEE International Conference on Robotics and Automation
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 2017 IEEE International Conference on Robotics and Automation, ICRA 2017
Y2 - 29 May 2017 through 3 June 2017
ER -