Tracy Staedter

Sep 30th 2019

The Human Exoskeleton Comes of Age


The human exoskeleton, an invention that arose in the 1960s, is finally coming into its own. Designed for medical, military and industrial applications, these wearable machines assist persons with limited mobility, augment human strength and endurance, and reduce the risk of worker injury. By transferring weight and load forces from a person’s body to an external, motorized frame, a human exoskeleton makes light work of heavy-duty tasks. And while the idea of augmenting humans with metallic frames may conjure images of fictional villains and mechanical superheroes, in reality, these devices are being developed to improve the lives of everyday people. Here’s how.

Better Than a Wheelchair

In the United States, about 288,000 people live with a spinal cord injury, according to the National Spinal Cord Injury Statistical Center. Not only can the medical costs from such injuries run into the millions over a person’s lifetime, pain and limited mobility can bring about feelings of hopelessness. Between 11% and 37% of people who suffer from spinal cord injuries experience depression, reports the Model Systems Knowledge Translation Center. To help them, research labs working on the future of robotics are developing assistive exoskeletons that give people a new way to get around.

Homayoon Kazerooni, director of the Berkeley Robotics and Human Engineering Laboratory and also the cofounder and CEO of suitX says that to assist people who cannot otherwise walk on their own, a human exoskeleton needs to do four things: help a person stand up, start walking, stop walking and sit down.

“These four things provide greater independence. They can move around, they can work, they can sit in front of a computer, they can work inside of a kitchen,” says Kazerooni.

Wheelchairs can’t do that.

But the Ekso GT and the Phoenix at suitX, both designed under Kazerooni, can. Each is basically a pair of wearable robotic legs — a mix of rigid and soft parts — that a patient puts on by placing their feet into footplates and then strapping the external frames to each leg. Using crutches for stability, they shift their weight slightly side-to-side to engage electronic motors in the frame. Mechanical joints at the hips and knees bend and move forward to produce a walking motion.

At first, the machine may do all of the work. But depending on the injury, the repetitive motion can, over time, reengage the patient’s muscles and nervous system. Sensors in the frame and motor monitor the progress and display the information on a screen for a physical therapist. If the therapist sees that the patient is getting stronger, he can reduce the power, encouraging muscles to work a little harder.

In the last few years, the Food and Drug Administration has approved several exoskeletons for walking assistance and rehabilitation, including suitX’s Phoenix, the Ekso GT, Cyberdyne’s Medical HAL, ReWalk Robotics and Parker Hannifin’s Indego. And in 2019, the health insurance provider Cigna announced it would change its policy to consider exoskeleton devices for individuals on a case-by-case basis.

Give Me Strength

Millennials are currently the talk of the town. But by 2035, adults age 65 and older will outnumber children under 18 for the first time in American history, according to a report from the Gerontological Society of America. It’s not just Americans that are getting older, either. Populations in Japan, Germany, France, Singapore and the United Kingdom will soon also see more elderly than young. At the same time, occupations that require strength, endurance or repetition, such as those in manufacturing, healthcare and the skilled trades, are facing job shortages, according to CBS News.

“You want to keep people working longer, but they can’t be put into these physically demanding positions — not without help,” says Eugene Demaitre, Senior Editor of the Robot Report.

That help could come from a human exoskeleton. According to the analyst firm ABI Research, shipments of industrial exoskeletons will grow from 7,000 units in 2018 to 301,000 by 2028, reaching a revenue of $5.8 billion by 2028. Assistive machines designed for the lower half of a person’s body can reduce the strain and fatigue of repetitive bending and lifting as well as protect knees and lower backs from injury. Those designed for the upper body protect the shoulders, neck and back.

Car manufacturers appear to be early adopters of this technology. Audi, for instance, has been testing startup Noonee’s Chairless Chair, a passive, wearable seat for workers who stand for hours on end. Hyundai Motor Group developed a similar device called the Chairless Exoskeleton (H-CEX) to reduce strain on knee joints, and the Hyundai Vest Exoskeleton (H-VEX) makes it possible for a worker to hold an extra 132 pounds overhead without effort.

In 2018, Ford announced it had partnered with Ekso Bionics to add wearable EksoVests to 15 assembly plants across seven countries. Some workers in these factories lift their arms overhead on average of 4,600 times per day. The EksoVest reduces fatigue and the possibility of injury by elevating and supporting a worker’s arms as they assemble parts that are chest height or higher. The vest fits workers between 5′ 2″ tall to 6′ 4″ tall and provides lift assistance from 5 lbs to 15 lbs per arm.

SuitX, which has sold 1,200 industrial exoskeletons internationally, entered into an agreement to implement exoskeleton technologies in Siemens’ factories around the globe. Kazerooni says that although discussion around the future of robotics suggests people will be supplanted by machines, it hasn’t happened yet. “At least for now, we can combine them,” he says.

March on Metal Warriors

For all the medical and industrial progress human exoskeletons promise, their origin lies in a military machine named Hardiman. Designed by General Electric engineer, Ralph S. Mosher, Hardiman was a hulking 1,500-pound wearable machine developed as a joint Army-Navy project. It had a force feedback system to sense the environment and 30 different joints that helped amplify human strength by a factor of 25. Although the prototype represented an engineering breakthrough, its weight, lack of stability and extraordinary power needs ultimately did it in.

But the Department of Defense still wants exoskeletons. Two of most advanced military machines being tested today are full-body, autonomously powered robotic exoskeletons from Sarcos. The Guardian XO and XO Max are rigid, hefty suits that can be put on and taken off in about 30 seconds. Unlike other exoskeletons that augment human strength, these machines bear it all. The XO can lift and support 80 lbs of weight for four hours at a time, while the XO Max can handle 200 lbs for up to eight hours. Both can walk at three miles per hour (Hardiman walked 2.5 mph).

The military has shown great interest. In 2019, the U.S. Special Operations Command contracted Sarcos to deliver a Guardian XO; in that same year the company announced a partnership with the Puget Sound Naval Shipyard to evaluate the exoskeleton. Previously, the U.S. Air Force had also signed contracts with Sarcos for the XO.

But although the original intention behind military exoskeletons has been to increase the strength, endurance, protection and tactical awareness of battlefield soldiers, these machines have yet to fulfill that vision. Earlier this year, Sarcos retired its futuristic Tactical Assault Light Operator Suit, or TALOS, saying that the large, relatively heavy machine wasn’t ready for the close, person-to-person environment of combat, reports Defense One.

U.S. military units are currently operating in parts of the world, such as the Middle East, that are warm, mountainous and dusty, where agility and comfort are going to be big factors, says Demaitre of the Robot Report. “A full-body battle suit is still the stuff of science fiction,” he says. For now, the military exoskeletons will be used mainly for industrial purposes, to load and unload materials, for instance.

Despite some limitations, human exoskeletons remain an important part of the future of robotics. Although originally conceived for battle, these machines will instead infiltrate healthcare and manufacturing to offer bodily support, rehabilitate injuries and bring mobility to people who cannot walk on their own. The future of robotics is just around the corner, but these machines are already making impacts in patient care, industrial labor and military performance. As the technology advances and demand for these devices grow, exoskeletons may be more common than wheelchairs.