'Prosthetic Emulator': New Tool for Designing More Stable Prosthetic Legs
Stanford University engineers have developed a more stable prosthetic leg, and a better way of designing them. Challenging terrain like a hiking trail or a cobblestone street could become more manageable for people who have lost a lower leg. The new design features a tripod foot that responds to rough or uneven terrain by shifting pressure between three contact points. The new prosthetic emulator tool allows the team to quickly emulate and improve their prototypes, and flips the design process on its head. Instead of building a prosthetic limb to test in the real world, the team built the basic tripod foot, and then hooked it up to powerful off-board motors and computer systems that control how the foot responds as a user moves over all kinds of terrain.
Transcript
00:00:00 There are about a million people in the United States who have amputation, and about 500,000 people who need lower limb prosthetic devices. The majority of the devices on the commercial market are just shaped carbon fiber. And I think we can do a lot better, especially if you look at the technologies that are out in other fields of robotics.
00:00:31 We use these tethered laboratory-based devices that are highly versatile. We call them prosthesis [? emulators. ?] And they allow us to try lots of different designs without the overhead of making new hardware. It's kind of a test bed. So we have it hooked up to these very large [? offboard ?] motors to ensure that we never run out of mechanical power. We have it connected to really powerful computers and all sorts of sensors to ensure that we never
00:00:56 run out of signals. These are robotic prosthetic devices that can sense the person's movement in the environment and then take corrective actions to help them with their balance or to propel them forward and make walking easier. We're using these as design tools, so people can have the physical experience of interacting with some new device without having [? to build it. ?] On experiment day, a participant will come in.
00:01:20 If it's their first time in the lab, we'll have a licensed prosthetist fit them to our device. And then after that, we will walk them through a series of conditions. So they'll just try to walk as normally as possible for about six minutes per condition. And while they're walking, we'll be recording a variety of measures, such as motion capture or energy expenditure.
00:01:43 So the prosthesis has sensors to tell where the toes and heel are in space, and sensors to tell how hard the toe is pushing on the ground. And an [? IMU ?] here. That senses where the device is in the lab space. So one of the things we're excited to do is translate what we find in the lab into lightweight and low power and therefore inexpensive devices that can be tested outside the lab. They're creative.
00:02:16 They're interesting. They're passionate. So that drives that same sort of sense in me. I enjoy working with the crew. Ultimately, down the line, I hope to benefit from, maybe, innovations they come up with. I think eventually it ends up helping not just me, but everybody else that's in my situation. [MUSIC PLAYING] For more, please visit us at stanford.edu.
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