(Video via Vanderbilt University)
There are several approaches to prosthetic limbs. One is a direct actuation, like a sensor to detect what action the user would like to perform. Another, newer approach, uses a bit of A.I.
A leg prosthetic developed by the Center for Intelligent Mechatronics at Vanderbilt University (VU) is allowing an amputee to walk with almost a perfect gait. It is the world's first pairing of a powered knee and ankle joints that work in unison. Craig Hutto, a 23-year-old amputee of a shark attack that is helping with testing, explained how the leg feels, "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.”
Onboard sensors detect the person's movements. The microcontrollers use the data to predict what actions the person is trying to perform and then assists in that action. The Vanderbilt prosthetic makes it much easier for amputees to walk, stand, sit, going up and down stairs or inclines. The UV team stated that their leg is 25% faster than standard (passive) prosthetics.
Hutto explained just how easy the leg helps him on inclines,“Going up and down slopes is one of the hardest things to do with a conventional leg. 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.”
This leg weighs about nine pounds. On a single charge, it can last 3 days of normal usage or up to 8 miles (<14 km) of continuous walking.
The electronics of the limb has been re-done 15 times, according to UV researchers. This is not the end of revisions either. Although this is the quietest in their models, further silencing motor movements is a focus point. The latest addition is an "anti-stumble routine." When the leg detects that the user is stumbling, it will lift to clear obstacles and replant itself. As if the user is about to trip over something, it will attempt to go over it.
The UV team now plans a prosthetic arm and exoskeleton based on the same concept.
Another amazing achievement in prosthetics. I would like to see a similar control interface from the prosthetic hand in the UV leg. So, the user could move the leg in non-walking and arbitrary ways. All things in due time, I suppose.