Prosthetic Categories

New Robotic Prosthetic Leg Improves Gait

    Researchers at the University of Michigan's (U-M) Robotics Institute have developed a prototype for a new kind of robotic prosthetic leg. It has smaller but more powerful motors that encourage a more natural gait when worn.

     A prototype of a new robotic prosthetic leg improves gait.

    With the improved motors—initially designed for a robotic arm on the International Space Station—this prototype is more efficient and quieter than other robotic leg designs.

    Its other notable features include regenerative braking and a free-swinging knee.

    Regenerative braking  

    With regenerative brakes built into the design, the robotic leg can charge its battery using energy captured by the foot when it strikes the ground. This feature offers prosthetic users more than twofold their daily walking needs on a single charge.

    Furthermore, this prototype produces more force even as it consumes only roughly half the battery power needed by most state-of-the-art robotic legs.

    No stiff joints; less muscle work  

    Conventional leg prostheses have several drawbacks. Prosthetic users often find that they need to exert more effort in the hip muscles to set the device in motion, requiring more energy than walking with a biological leg. Because of all the extra muscle work, conventional leg prostheses can lead to joint damage and more pain.

    Another drawback is joint stiffness, which is more pronounced in users of robotic legs. The team of researchers at U-M addressed these problems in the prototype.

    The researchers designed the robotic leg's joints to be as flexible as possible. Once it is commercially available, prosthetic users will find that the leg's free-swinging knee feels almost similar to a biological one.

    Those who tested the prototype reported that they felt the leg pushing off the ground while they walked. This minimized the need to make their hip muscles work harder.

    The next phase of this development involves improving the leg's control algorithm, so it can quickly adjust to change in pace, varying terrain, and shift between different activities.

    Are you currently using a microprocessor-controlled prosthetic leg? If you are, would you consider getting yourself a new one once this prototype is commercially available?