Know Your Mechanical Exoskeletons

Argo Medical Technologies expects big things for 2014. In the coming months the company's powered exoskeleton, ReWalk, will be the first of its kind to receive an FDA Class II clearance—a decision that will help transition wearable machines from the rehab center to the home and workplace.

In the meantime, exoskeletons have advanced on other fronts. This month Ekso Bionics unveiled its Ekso GT, designed to help stroke victims regain an even walk, and in May U.S. Special Operations Command tapped industry for Iron Man-suit concepts (sans rocket boots and hand blasters).

Welcome to the future, where there is an exoskeleton for nearly any use, from rehabilitating car-crash victims to supporting a factory worker through his shift to turning a soldier into a human battering ram who can crash through doors and shrug off AK-47 rounds.

Developed in 2004 by Argo Medical Technologies founder Amit Goffer, who had suffered a severe spinal-cord injury, ReWalk is designed to help those paralyzed from the midchest down go about their daily routine as if they were operating a walking, electric wheelchair. By contrast, most other medical exoskeletons are strictly rehab tools. "Users don't have independent control," says Argo CEO Larry Jasinski. "Someone walks behind them and pushes a button, or they do something else. And many of them are tethered to a ceiling."

So far, ReWalk has seen limited use in Europe and Israel, but an FDA certification will crack the American market wide open. Jasinski then expects to sell ReWalk in the U.S. for around $60,000 and hopes insurance companies will foot some of the bill—he argues that ReWalk will save them money they would otherwise spend on expensive medicines and procedures. "If you take a body and don't let it walk, it deteriorates like you wouldn't believe," he says.

A ReWalk will last, on average, five years, but Janinski believes that's still enough time to see savings accrue. To make its case, Argo Medical Technologies is designing studies with insurance companies "so that they are more likely to be comfortable with the data at the other end," he says.

Russ Angold, cofounder and CTO of Ekso Bionics (formerly Berkeley Bionics), got into medical exoskeletons by way of military devices. In 2004 he joined the University of California, Berkeley's robotics lab after it had created Bleex, the world's first untethered, powered exoskeleton, and he was ready to work on Gen II. However, Angold's Navy SEAL brother was unimpressed with the big, 5-kilowatt machine.

"I'm showing him the videos [of Bleex]," he recalls, "and he says, 'You know what? It isn't going to work. It's too loud. It's too heavy. It's too slow. The gas engine on the back is a nonstarter.'"

So when Angold spun off from his lab a year later, his company produced scaled-down exoskeletons, including the Human Universal Load Carrier (HULC). HULC, leased to Lockheed Martin in 2009, allows a soldier to march comfortably with 200 pounds on his back or run for bursts of 10 mph.

Ekso Bionics has made inroads into healthcare with rehab exoskeletons designed to train spinal-cord-injury victims to walk on their own again. In 2012 Angold sold the first Ekso. Now the $100,000-plus units can be found in hospitals nationwide, including Mt. Sinai Medical Center, Kessler Institute for Rehabilitation, and Walter Reed Army Medical Center. This month the company launched its Ekso GT for stroke victims. The device, he says, offers more unlockable joints, more ankle adjustment, and has a "quicker changeover time between patients" than did previous systems.

Homayoon Kazerooni, a professor of mechanical engineering at University of California, Berkeley and the head of its robotics lab, says the future of exoskeletons is on the factory floor. That means they have to be cheap. "You can't make a $135,000 machine and put it on an assembly line," he says, referring to Ekso's price tag.

Kazerooni was a cofounder of Berkeley Bionics but has since returned to the lab, where he has created a still-unnamed exoskeleton that costs just $15,000. "The one we have is so light that you can wear it under your clothing," he says, adding that a major Japanese manufacturer wants a few of his low-powered exoskeletons in its factories by early 2014.

In similar vein, the Navy is testing an unpowered MANTIS Human Augmentation System for maintenance work. That exoskeleton is paired up with an Equipois zeroG arm to aid workers who don't have to walk around much but do have to lift heavy tools, such as grinders.

Lockheed Martin, working with the Navy on MANTIS, argues that its frame increases worker productivity by 70 percent. But Kazerooni says it's just a HULC stripped of its actuators and balanced with added weight on its back. "It's really Philistine," he sniffs.

What factory workers, especially older ones, need is something that supports them even when tightening light screws, he says. "It's not the weight that leads to injury; it's bending their back, their posture," he says.

Special Operations Command wants Iron Man. Of course. So in May, the Army's Research, Development and Engineering Command put out a request for information for ideas on a Tactical Assault Light Operator Suit (TALOS). Basically, TALOS is a fast-moving, high-powered armored exoskeleton to be worn by the first guy through the door. As Angold puts it, "It's a bit of human tank."

By contrast, the Defense Advanced Research Projects Agency is looking at a soft exo-suit as part of its Warrior Webb concept. Using textiles and elastomers (polymers with rubberlike elasticity), this suit will enhance a soldier's endurance but not necessarily improve his load carriage, says Conor Walsh, the Harvard engineering professor who leads a team of researchers on the project.

By going the soft route, "the wearer's joints are unconstrained by external rigid structures, and the worn part of the suit is extremely light, which minimizes the suit's unintentional interference with the body's natural biomechanics," Walsh says.

Still, an infantry unit in the future might actually employ both suits. As with every exoskeleton—medical, industrial, and military—it all depends on the needs of the operator.