Vanderbilt's New 'Bionic' Leg Mimics Natural Movement

Researchers at Vanderbilt University have recently invented a new electronic prosthetic leg that allows amputees to move more naturally. Conventional prostheses can cause pain and muscle stiffness for amputees because they do not move in the same way that bones and muscles naturally move. This new cutting edge prosthetic leg avoids some of these issues by using new technology to create powered joints that operate together to provide a smooth, natural gait. The lower leg prosthesis has been dubbed a “bionic” leg because it uses technology such as motors and batteries to power the leg, but it relies on sensors to monitor and control motion. Sensors monitor changes in the user's balance and muscle movement and send signals to the microprocessors to control the leg movement. Electric motors in the knee and ankle joints then complete the movement using battery power. The prosthesis weighs in at around nine pounds, less than a human lower leg, and uses over 30% less energy to operate than conventional fixed leg prostheses.

Craig Hutto, the 23-year-old amputee who tested the leg for Vanderbilt University, told Science Daily about his experience with the new prosthesis: "When it's working, it's totally different from my current prosthetic. A passive leg is always a step behind me. The Vanderbilt leg is only a split-second behind." The new “bionic” leg allows for a wide range of movement, providing amputees with the ability to tackle obstacles, walk up and down slopes, and even avoid falling. Amputees can easily navigate stairs, and an innovative anti-stumble routine in the microprocessors that control the leg helps users regain their balance if the sensors report that the user is beginning to lose balance. "Going up and down slopes is one of the hardest things to do with a conventional leg," Hutto stated. "So I have to be conscious of where I go, because I can get very tired walking up and down slopes. But that won't be a problem with the powered leg, because it goes up and down slopes almost like a natural leg."

The powered prosthetic leg has been in development at the Vanderbilt Center for Intelligent Mechatronics for seven years. Research grants were given to the project by the National Institutes of Health and the National Science Foundation. Work is still being done on the “bionic” leg in order to give amputees more mobility and ease of use. The electronics within the leg are constantly being tweaked as researchers refine the prosthesis for manufacture by Freedom Innovations, a company that specializes in lower-limb prosthetic devices. Developers are also trying to make the leg quieter and lighter. Check out the video below to see where they're at now:

Sources: http://news.vanderbilt.edu/2011/08/bionic-leg/ http://www.wired.com/gadgetlab/2011/08/motorized-bionic-leg-moves-like-a-real-leg/