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VR Interfaces: ReWalk


Overview of ReWalk

ReWalk is an exoskeletal framework, based in part on recent robot gait algorithms. Its primary purpose is to allow wheelchair users to walk again - even if their own legs no-longer work.

De veloped by engineer Amit Goffer, founder of Israeli Argo Medical Technologies, is designed specifically to give the paralysed their ability to walk back.

ReWalk is advanced enough to take over simple fuinctions such as walking at a steady pace, handling stairs, sitting down and getting up, without relying on input from the user's nerves.

ReWalk consists of motorised leg supports, body sensors and a back pack that contains a computer and rechargeable batteries. Crutches are also required, as balance control is still a problem, and the user's arms are necessary to correct this. Ironically, because the arms are necessary, Goffer is unable to use ReWalk himself.

Goffer became paralysed in an accident in 1997, but because he lacks full use of his arms, he cannot balance with the system in its current incarnation. Still, that is motivation to keep refining it.

The video below shows former Israeli paratrooper Radi Kaiof, paralysed from the waist down for the past 20 years, walking about and interacting with his family, using ReWalk. The video also shows him driving a car, but it should be noted, that the car is adapted for hand-control, the ReWalk cannot handle precise gestures such as acceleration, deceleration, and emergency stop swiftly enough to be safe, yet.

"I never dreamed I would walk again. After I was wounded, I forgot what it's like," said Kaiof, who was injured while serving in the Israeli military in 1988.

"Only when standing up can I feel how tall I really am and speak to people eye to eye, not from below."

To control the frame, a wrist-pad is worn, similar in appearance to the bulky worn interfaces of TV in the 50s and 60s. On it are a handful of buttons, large and indented, to aid users with limited arm control as much as possible. These allow the user to change the mode the exoskeleton is in. It has several modes, each utilising a very different gait and limb movement. The standard settings are:

  • Stand (from sitting)
  • Sit
  • Walk (fixed pace)
  • Descend (stairs)
  • Climb (stairs)

The device cannot handle very uneven ground at this time, and steep slopes such as ramps can be a problem due to the fixed nature of walking speed. It is basically limited to urbanised areas, but is still an impressive stride forward, restoring mobility to wheelchair users, that was a pipe dream just months ago.

To command the unit, the desired preference is chosen, and then the user leans theirt upper body forwards. This tilts the internal gyroscopes, which initiates movement. Movement continues in whichever preset pattern was chosen, until the user tips back, or a solid obstruction is reached.

The battery power is sufficient to use it all day, but it must be charged overnight. The user's own legs do not even have to support the user's weight, initially - ReWalk is strong enough to do that for muscularly depleted legs.

ReWalk is in clinical trials in Tel Aviv's Sheba Medical Centre, with more scheduled at the Moss Rehabilitation Research Institute in Pennsylvania, US.

ReWalk is slated for commercial sale in 2010 at $20,000 - a price competitive with the more sophisticated wheelchairs on the market.

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