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Prosthetic ankle and method of controlling same based on adaptation to speed

  • US 9,707,104 B2
  • Filed: 03/12/2014
  • Issued: 07/18/2017
  • Est. Priority Date: 03/14/2013
  • Status: Active Grant
First Claim
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1. A method of controlling a prosthetic ankle device, comprising:

  • providing the prosthetic ankle device, the prosthetic ankle device comprising a foot unit, a lower limb member configured to move relative to the foot unit, the foot unit and lower limb member defining an ankle angle therebetween, and an actuator configured to affect the ankle angle defined between the foot unit and the lower limb member, wherein the actuator comprises an active actuator configured to provide the movement between the foot unit and the lower limb member;

    determining gait speed based on data provided by one or more sensors on the prosthetic ankle device; and

    operating the active actuator of the prosthetic ankle device based on the determined gait speed, wherein;

    at gait speeds less than a first threshold speed, the active actuator of the prosthetic ankle device is operated using a neutral ankle angle curve, wherein the neutral ankle angle curve represents a relationship between percent of completion of a stride of a user of the prosthetic ankle device and number of degrees of the ankle angle, wherein the first threshold speed is greater than zero;

    at gait speeds at or above the first threshold speed and below a second threshold speed and traversed across a level surface, the active actuator of the prosthetic ankle device is operated using a first speed adaptive ankle angle curve that is shifted relative to the neutral ankle angle curve so that, for each percent of completion of the stride corresponding to a same percent completion of the stride on the neutral ankle angle curve, the prosthetic ankle device is more dorsiflexed than when the active actuator of the prosthetic ankle device is operated using the neutral ankle angle curve; and

    at gait speeds at or above the second threshold speed and traversed across the level surface, the active actuator of the prosthetic ankle device is operated using a second speed adaptive ankle angle curve that is shifted relative to the neutral ankle angle curve so that, for each percent of completion of the stride corresponding to a same percent completion of the stride on the neutral ankle angle curve, the prosthetic ankle device is more plantarflexed than when the active actuator of the prosthetic ankle device is operated using the neutral ankle angle curve.

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