Modular exosuit helps paraplegic ex-trapeze artist walk again

A modular lightweight exoskeleton has allowed former circus acrobat Silke Pan to walk again after a fall from a trapeze rendered her paraplegic ten years ago.

When searching for talented pilots, the EPFL team approached the Swiss Paraplegic Foundation. The organization redirected them to the Wheelchair Club Lausanne. Ms Silke Pan thus heard of the project through one of the club members and responded enthusiastically. Twiice Photo

By Jim Drury, Reuters, GMA News February 14, 2017

In 2007, Silke Pan was a 34-year-old renowned circus acrobat, at the top of her profession. But a fall from a trapeze left her paraplegic and facing the rest of her life in a wheelchair.

Despite her obvious devastation at losing the use of her legs, Pan had adapted to her unexpected status, and forged a successful career as a handcycle athlete.

But now Pan is walking again, thanks to a prototype exoskeleton pioneered by the Robotic Systems Laboratory (LSRO) at École Polytechnique Fédérale de Lausanne (EPFL).

Pan told Reuters: “The first time that I stood up with the exoskeleton was really emotional for me. It was as if I were in a dream. I couldn’t believe it. To see my legs moving and making the movement of walking was really so phenomenal.”

The TWIICE exoskeleton allows Pan to walk in various directions, turn, and even climb steps.

It weighs just 14 kilograms (30.8 pounds) and consists primarily of composite materials. Two electric motors on each leg allow the movements of flexion-extension of the hip and knee joints. With a charge that can last for up to three hours, it should provide enough daily independence for most requirements. The battery takes just half an hour to charge.

Once strapped into the exoskeleton, patients walk with the aid of crutches containing buttons in the handles that help users walk at various speeds, go up and down steps, and change direction. Most current exoskeletons only allow forward motion.

Tristan Vouga, a PhD student in micro-engineering, devised the concept.

“TWIICE is made of two main components,” he told Reuters. “The first one is the structure, so it acts like the bones of a normal leg. It makes the whole thing hold together, and then there are the electrical motors. These are like muscles that make the whole structure move as you’re moving your leg. These electrical motors have a gear reduction also included that makes the whole torque stronger.”

Vouga enlisted the help of Pan to refine the technology while constructing the prototype.

PolyWalk team in front of the Rolex Learning Center, EPFL. Since July 2016, Ms Pan has piloted the exoskeleton periodically two or three times per week. Her help contributed to many enhancements such as the adjunction of a system of auditory feedback. It helps to synchronize her own actions with TWIICE: the first signal indicates her foot detachment and the second one the end of the cycle, in other terms the return of the weight on the foot. Twiice Photo

Pan felt the belt was initially too low, while also suggesting that audio be added to various movements, such as when her feet landed on the floor, allowing her to look straight ahead confidently, knowing her feet were grounded during each step.

She then trained in the exoskeleton for three-hour sessions three times a week, and within a month felt confident to walk independently. Now Pan says it feels almost as if she is walking normally.

According to Vouga, one of the advantages of TWIICE is that it can be easily adapted to fit different bodies and work with different disabilities.

“This technique is a bit like 3D printing,” he said. “It’s also very versatile. We can create any shape we want, but it’s much more high-performance. It’s very lightweight, but also very very strong. So it’s made with composite materials but we can create any shape that we want very quickly and without the need of expensive tooling or expensive investment at the front end.”

Project supervisor Mohamed Bouri, LSRO group leader, hopes his team can help make it commonplace to see people walking around in exoskeletons.

“Our objective is really to develop and give the accessibility to exoskeletons, to more people, to more pathologies, to more needs, and this is why we are really targeting daily living activities,” he said. “When I say daily living activities I’m mainly speaking about sitting to standing, about going upstairs, in order to be capable to walk both indoors and outdoors.”

Bouri says that giving paraplegics the ability to stand will give them the feeling of parity, by sharing a common space with the able-bodied.

“We are trying to democratise this exoskeleton concept by developing lightweight, cost-affordable, exoskeletons, and by giving the exoskeletons more daily living functions,” said Bouri.

A modular lightweight exoskeleton has allowed former circus acrobat Silke Pan to walk again after a fall from a trapeze rendered her paraplegic ten years ago, as she demonstrated to Jim Drury. Published on YouTube Feb 13, 2017

Pan wore the exoskeleton at last October’s prestigious Cybathlon, the international sports competition for disabled athletes who use assistive technologies.

The German athlete says she feels less disabled while wearing the exoskeleton than she does in her wheelchair, and hopes others will benefit similarly.

“I hope that in a few years people like me will be able to choose between a wheelchair and an exoskeleton, maybe to have both and to live their daily life with it; to go shopping with it, to climb stairs, to climb a ladder, to go picking up an apple from the tree,” said Pan.

Researchers are now working on improving the suit’s ergonomics.

The team is among the finalists at the United Arab Emirates AI and Robotics Award for Good competition, taking place in Dubai on February 17-18.

According to its organisers, “the award intends to support innovation in the key area of artificial intelligence and robotics as part of the UAE’s commitment towards the National Innovation Strategy.”

Source Reuters via GMA News

Also see
Technology gets disabled people back on their feet in École Polytechnique Fédérale de Lausanne, EPFL
Driving innovation forward with exoskeleton TWIICE at Cybathlon in Fischer Connectors

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