Kate Allyn, CPO, is the prosthetist on the project, which is being led by Sanders at her lab at the University of Washington Department of Bioengineering.
“[The small changes] have a big impact because they maintain a fit between residual limb and socket that is not too tight and not too loose—but just right,” said Allyn.
A gel interface material in the prosthetic sleeve contains a small amount of iron, and sensors embedded in the socket wall detect the distance to the iron in the gel and send that data to the socket’s microcontroller. The microcontroller calculates whether adjustments are needed. If so, it transmits instructions to three motorized panels within the socket wall—two in the front, one in the back—and they move to make the socket smaller or larger in increments less than a millimeter at a time. Changes can also be controlled manually via an app on the user’s smartphone.
Through user trials, Sanders’ team is collecting more detailed data on the device’s performance and is working to make the prototype’s motors smaller and lighter.