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July 24, 2020


Motors originally designed for the International Space Station are part of a new robotic prosthetic leg design that's more comfortable and offer users a more natural gait. It's the work of a National Science Foundation-funded team at the University of Michigan and University of Texas at Dallas.

Credit: National Science Foundation/Karson Productions


I'm Bob Karson with the Discovery Files, from the National Science Foundation.

Prosthetic legs are improving, but they're not perfect. Conventional ones cause an unnatural gait. Users have to raise their hips to lift the foot from the floor and swing the leg forward. (Sound effect: clunk!)

Robotic prosthetics are more comfortable, (Sound effect: robotic bursts) but their small motors need many gears to increase the force. Which adds noise and weight and makes the joints stiffer. A trade-off greatly reduced by researchers at the University of Michigan and the University of Texas at Dallas, with a newly designed leg prosthetic inspired by the robotic arm of the International Space Station.

(Sound effect: spacey reverb) Turns out that big honkin' robotic arm on the ISS uses small, more powerful motors with an original design. One the team borrowed and applied in their new prosthetic. One motor for knee power, one for ankle. Less gears -- for a naturally free-swinging knee that notches down the noise.

The leg consumes about half the battery power of state-of-the-art robotic legs. Even charges the battery with energy captured when the foot hits the ground. Amputees testing the design say it helps them push off as they walk, is more comfortable, and gives them a more natural motion.

(Sound effect: robotics sounds) Next, adjusting for terrain, pacing and transitions between activities.

Stepping up the game, by making some amazing strides.

"The discovery files" covers projects funded by the government's National Science Foundation. Federally sponsored research -- brought to you, by you! Learn more at or on our podcast.

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