Navigating difficult terrain is not much of a challenge for most people, but traversing something as commonplace as uneven pavement can pose stability problems for those with lower limb prosthetics. Mechanical engineers at Stanford University hope to achieve a greater measure of motive stability for this The foot incorporates three rubber contact points — two front toes and one rear heel. Source: Stanford Universitypopulation with a new tripod foot design that responds to rough terrain by actively shifting pressure between three different contact points.

The redesigned prosthetic uses the heel and two toes as the contact points, and onboard sensors and motors enable the device to monitor terrain and control movement so as to maximize stability. The design phase itself is streamlined with an emulator system that accelerates the prototyping and testing process. The assembled tripod prosthetic is connected to the emulator’s off-board motors and computer systems that control how the foot responds as a user moves over different types of terrain.

Various tests have been conducted with the lightweight, compact emulator to determine torque measurement accuracy, closed-loop torque control bandwidth, torque tracking error and center of pressure control accuracy. The system was demonstrated to support rapid development of controllers designed to enhance user balance.