A computer-controlled actuator operates a camera that helps a robotic ankle “see” what’s ahead. Photograph courtesy of Michigan Technological University.
Mo Rastgaar, PhD, is poised to take a giant step forward in the development of prosthetic ankles.
The Michigan Technological University mechanical engineer and his team have already developed a prototype that can provide a range of motion that rivals a natural gait. Next, they aim to give their robotic ankle something different, eyes.
“We are developing an artificial vision system,” said Rastgaar, an assistant professor of mechanical engineering-engineering mechanics. The key components are a low-cost camera and a computer-controlled actuator, which adjusts the ankle’s position through a system of cables.
“The camera can identify the profile of the ground, while the computer knows where the next footstep will be, based on how the user is moving the leg,” he explained. “Then the computer analyzes the information from the camera and applies the correct angle and stiffness to the ankle, just as you would with your biological foot and ankle.”
Thus, the ankle could adapt precisely, whether the user is climbing stairs or striding over a pothole.
Rastgaar’s team has also refined the actuator’s design, making it lighter and more streamlined. Because the foot is moved by lines similar to bicycle brake cables, the actuator does not have to be mounted on the prosthesis, where the user must move it with every step. Instead, it could be carried in a pocket or fanny pack, for example.
“Also, this new actuator system will be easy to remove, so you can use it or not, based on your needs,” Rastgaar said. “If the user is going to stay at home, it might be simpler to walk around the house with a passive prosthesis.”
He hopes that eventually their robotic ankle will find its way out of the lab and onto the sidewalk.
This article was adapted from information provided by Michigan Technological University.