An exoskeleton powered by air can flex the wrists with a rotation approaching that of the natural joints. Such a device could help people rehabilitate from wrist-related injuries at home by building strength.
at the University of Notre Dame in Indiana and her colleagues used balloon-like materials to create inflatable artificial muscles for their exoskeleton. These can be blown up with air to move components within the device.
When assessed in lab tests, the exoskeleton rotated a mock-up of a wrist using the force created by the artificial muscles’ inflation and deflation.
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The researchers found that the exoskeleton mimicked 55 per cent of a natural wrist’s range of movement for flexion, defined as moving the joint in a downwards direction from a flat position.
It also achieved 69 per cent of a wrist’s range of movement for extension, moving it up from a flat position, and around 68 per cent for ulnar and radial deviation, the side-to-side movement used when waving.
at the University of Sheffield, UK, says the most interesting part of the device is the soft material elements that make up its artificial muscles. “This provides the wearer with a lightweight system that appears, from the photographs in the paper, to be much more natural than bulkier servo-based exosuits.”
The exoskeleton, which weighs 160 grams, can also recreate how many muscles contract when they go to move a joint, he says. These muscles often work in pairs, with one contracting as the other relaxes. The exoskeleton achieves this “without resorting to fixed structures, which are typically more unwieldy”, says Aitken.
Writing in their paper, the researchers say they hope their device can one day be used to help people do injury rehabilitation exercises at home. They plan to develop their prototype to reduce its size and manufacturing costs, which come to $134 for the exoskeleton itself and $3572 for a tethered console that controls it.
arXiv
