This smart prosthetic ankle adjusts to rough terrain

By Devin Coldewey

Prosthetic limbs are getting better and more personalized, but useful as they are, they’re still a far cry from the real thing. This new prosthetic ankle is a little closer than others, though: it moves on its own, adapting to its user’s gait and the surface on which it lands.

Your ankle does a lot of work when you walk: lifting your toe out of the way so you don’t scuff it on the ground, controlling the tilt of your foot to minimize the shock when it lands or as you adjust your weight, all while conforming to bumps and other irregularities it encounters. Few prostheses attempt to replicate these motions, meaning all that work is done in a more basic way, like the bending of a spring or compression of padding.

But this prototype ankle from Michael Goldfarb, a mechanical engineering professor at Vanderbilt, goes much further than passive shock absorption. Inside the joint are a motor and actuator, controlled by a chip that senses and classifies motion and determines how each step should look.