Bio-inspired design and validation of the Efficient Lockable Spring Ankle (ELSA) prosthesis

Over the last decade, active lower-limb prostheses demonstrated their ability to restore a physiological gait for transfemoral amputees by supplying the required positive energy balance during daily life locomotion activities. However, the added-value of such devices is significantly impacted by their limited energetic autonomy, excessive weight and cost, thus preventing their full appropriation by the users. There is thus a strong incentive to produce active yet affordable, lightweight and energy efficient devices. To address these issues, we developed the ELSA (Efficient Lockable Spring Ankle) prosthesis embedding both a lockable parallel spring and a series elastic actuator, tailored to the walking dynamics of a sound ankle. The first contribution of this paper concerns the developement of a bio-inspired, lightweight and stiffness-adjustable parallel spring, comprising an energy efficient ratchet and pawl mechanism with servo actuation. The second contribution is the addition of a complementary rope-driven series elastic actuator to generate the active push-off. The system produces a sound ankle torque pattern during flat ground walking. Up to 50% of the peak torque is generated passively at a negligible energetic cost (0.1 J/stride). By design, the total system is lightweight (1.2 kg) and low cost.

Published in:
2019 Ieee 16Th International Conference On Rehabilitation Robotics (Icorr), 411-416
Presented at:
16th IEEE International Conference on Rehabilitation Robotics (ICORR), Toronto, CANADA, Jun 24-28, 2019
Jan 01 2019
New York, IEEE

 Record created 2020-10-08, last modified 2020-10-25

Rate this document:

Rate this document:
(Not yet reviewed)