Sat. Feb 4th, 2023
A prototype of the exoskeleton
Enlarge / A prototype of the exoskeleton

Hillary Sanctuary/EPFL

With a slip and a turn, a robotic device that fits around an elderly person’s pelvis could prevent a dangerous fall, Italian researchers report in Scientific Reports.

Like the short version of exoskeleton pants, the device can sense an imminent fall within 350 milliseconds and apply torque directly to the wandering limb. The robotic hip rotation corrects the person’s center of gravity and successfully avoids a fall. In early prototype trials, eight elderly people and two elderly people with prosthetic legs could all remain upright while walking on a sliding treadmill designed to induce tripping.

The researchers hope that their device, called the Active Pelvis Orthosis, or APO, can significantly improve the health of the elderly. Every year, millions of people age 65 and older fall. They are the leading cause of fatal and non-fatal injuries in that demographic, causing 95 percent of hip fractures and most traumatic brain injuries. The resulting health care costs are estimated to be $31 billion a year in the US alone.

In terms of fall prevention, the APO has an edge over the competition, say the researchers. Unlike other mobility aids and exoskeletons, theirs doesn’t try to take over a person’s movement. The APO idles at the waist, learns quickly, and then follows a person’s gait. It only kicks in with force when it detects that a limb is out of alignment. This is critical, say the authors, because most elderly people prone to falls can and will attempt a fall themselves. Only they are often not strong enough to get it done.

“In this situation, it is necessary to develop ecological and symbiotic solutions that can help only when needed,” the authors wrote.

For that only-when-needed robot uncle, the researchers designed a waist that hugs the waist and connects to the thighs. The braces are made of lightweight carbon fiber and there are motors that sit on the side of each hip. The APO is attached to a computer and tracks the movement and angle of the limbs and hips as a person walks. With just a few steps, a custom algorithm can figure out a person’s individual gait and detect anomalies. When a hip hits the wrong angle and the wearer begins to lose balance, the device reacts in less than half a second. It applies a twisting force to both hips to push the thighs down and restore stability. The force is designed to be soft and calculated according to the weight of the wearer.

To test the APO, the researchers had their 10 tethered subjects walk on a split belt treadmill, in which the belts can move independently and slide apart to allow a user to slip. When that happened, the APO quickly restored the users’ balance so they could stay upright and walk normally again, the researchers found.

Smart exoskeleton recognizes loss of balance and prevents falls

But, they note, “challenges lie ahead after this promising proof of concept.” Much more testing and trial will be needed to see how the APO might work in real life – with real, clumsy falls and other frail elderly people. The researchers are also working to make the device untethered and less bulky and conspicuous. At the moment, it weighs about 4.2 kilograms (about nine pounds), which can be a challenge for some. There’s also no word on what a final device might cost for an elderly patient, who is often on a tight budget.

Still, APO wearers are impressed so far, including 69-year-old Fulvio Bertelli, who tried the device at a hospital in Florence and said it helped and protected him. “I feel more confident wearing the exoskeleton,” he said.

Scientific Reports2017. DOI: 10.1038/srep46721 (About DOIs).

By akfire1

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