Robotic legs get wheelchair users walking

A new pair of robotic legs out of New Zealand lets wheelchair users do the improbable--stand, walk, and even go up and down stairs.

Users transfer themselves from their chair into the Robotic Exoskeleton (Rex) by holding on to Rex's legs. They then strap themselves in and use a hand-controlled joystick and control pad to maneuver the battery-powered mobility-assist device on solid, stable surfaces such as those inside the home or workplace. (Rex is not designed for use on slippery or soft surfaces, or in areas containing debris or small objects such as ice, snow, sand, grass, mud, or gravel.)

Hayden Allen suffered a spinal cord injury five years ago during a motorcycle accident and is one of the first people to use Rex. He said walking with the help of the machine for the first time spurred "a hundred million emotions.

"I'll never forget what it was like to see my feet walking under me the first time I used Rex," said Allen, a 6-foot-4-inch mechanic. "People say to me, 'Look up when you're walking,' but I just can't stop staring down at my feet moving."

Aside from the elation of standing; walking (albeit slowly, as you can see from the video below); looking directly into friends' eyes; and reaching tall shelves, Allen says he's experiencing concrete health benefits from spending less time in a seated position. He's getting fewer bladder infections, for example, his muscles and joints feel less stiff, and he's noticed that cuts and bruises heal more quickly.

The 84-pound robotic legs were developed by Auckland-based Rex Bionics. Company founders Richard Little and Robert Irving both have mothers who use wheelchairs, so they're familiar with some of the challenges and frustrations those in wheelchairs face.

In addition, more than seven years ago, Irving was diagnosed with multiple sclerosis, an autoimmune disease that attacks the central nervous system and can in some cases lead to paralysis. That's when the pair decided to apply their engineering know-how to developing a standing and walking complement to wheelchairs; they've been working on their invention since.

A lightweight rechargeable battery powers the machine; a full charge typically runs for two hours of active use.

There are some limitations on who can utilize the device. Users need adequate upper body strength and functionality to transfer themselves into the exoskeleton and operate the hand controls. Also, to fit into the chair, customers need to be between 4-foot, 8-inches and 6-foot, 4-inches tall; weigh less than 220 pounds; and have a hip girth of less than 14.9 inches.

Then there's the price--around $150,000. Rex is currently available for purchase and fitting in New Zealand, and is expected to be available in other countries next year.