In Edge of Tomorrow, a critically acclaimed science fiction movie released this summer, soldiers fight aliens with powered exoskeletons that enhance their strength, speed and agility. On the silver screen, alongside explosions and otherworldly enemies, the ideas seems like a Hollywood invention – but it’s closer to reality than you’d think.
Exoskeleton research has been underway for over a century, resulting in a number of viable prototypes. Surprisingly, though, they focus less on super-human strength and more on improving endurance and quality of life. Researchers in the field see the future as a marathon instead of a sprint.
Human exoskeletons have appeared in science fiction stories since the 1950s, but the first real exoskeleton was invented over a half-century earlier by Russian inventor Nicholas Yagn. Despite his country of residence, he decided to file a patent with the United States Patent Office in 1890. He described his invention as:
[…] a number of springs adapted to support the weight of the entire body and store and accumulate the power exerted thereby, together with the power exerted by the momentum of such dead-weight when in motion. – Nicholas Yagn, inventor
His exoskeleton also used “compressed-fluid accumulators” to store energy. According to Nicholas, his invention gave users better mobility and reduced the strain of running and jumping on the body. Sorry, steam-punk fans; this was no gear-driven death machine.
The first powered exoskeleton, called Hardiman, was developed by General Electric in the late 1960s. Massive and brutish, the suit looked much like the massive battle-suits envisioned by sci-fi authors. It was designed to amplify a user’s strength substantially, but its inventors never completely nailed down the controls and power requirements. As stated in the project’s final report:
The man-machine interface problem in the Hardiman I prototype has been a severe one. The high power gain, the complexity of the multi-jointed system and the intimate coupling of the man and machine imposed many design constraints and made heavy demands on existing technology.
The failure of Hardiman demonstrated the extreme difficulty of developing an exoskeleton with that era’s technology. Another attempt wasn’t made until the early 1990s, when researchers at Kawasaki began work on the Power Assist Suit, an exoskeleton designed to help medical professionals move immobile patients.
An explosion of new development occurred after the turn of the century. Japanese company Cyberdyne introduced the HAL-3 exoskeleton concept, Berkeley developed a lower body exoskeleton called Bleex to help soldiers carry heavy loads over long distances, and Honda has put together a pair of lower body exoskeletons designed for partially mobile people who might otherwise need a cane or walker.
The failed Hardiman project is the kind of suit most people think of when told to imagine an exoskeleton. Many of us recall images from fiction, such as the famous exoskeleton piloted by Sigourney Weaver (or rather, the stuntman hidden behind her) in Aliens.
A massive exoskeleton can certainly wow an audience, but its practical use is limited. Batteries still lack the endurance needed to power a beastly machine for long periods of time, and a large exoskeleton doesn’t do much a forklift, crane or other vehicle can’t already achieve. Modern exoskeletons focus on enhancing humans in practical ways that can be of use every day in a variety of situations.
One of the latest designs is the Human Universal Load Carrier, or HULC, a military exoskeleton designed by Lockheed-Martin to greatly enhance the physical capabilities of soldiers. The basic idea, as stated by program manager Jim Ni and detailed in a company press release, is to augment endurance and strength while also decreasing the risk of injury.
It [HULC] enables soldiers to do things they cannot do today, while helping to protect them from musculoskeletal injuries. – Jim Ni, HULC program manager
That doesn’t sound much different from the benefits Nicholas Yagn claimed for his exoskeleton over a century ago, but modern technology means researchers can better realize the idea. HULC can help solders carry loads of up to 200 pounds over various terrain while minimizing the risk of injuries that could slow a soldier in the field. Batteries power the exoskeleton, which weighs over fifty pounds, and life can extend up to 72 hours with special equipment.
But Lockheed-Martin is not the only company in this field. Raytheon has spent the last eight years developing the XOS, which hopes to fill the same role as the HULC. Unlike its competitor, though, the XOS covers a substantial portion of the user’s lower and upper body. Its inventors quote a similar maximum carrying capacity of at least 200 pounds, but the enhancement of strength extends to the arms, which can hold up to fifty pounds with little effort.
Not Just For Soldiers
In Japan, meanwhile, Cyberdyne has continued development of its HAL-5 exoskeleton. Unlike its American peers, this device is built for civilian rather than military use. The company is researching several models for use by industrial workers, disaster response personal and medical professionals.
A lower-limb model designed to help rehabilitate people with injury-related mobility issues has been approved for use in Europe and is being used in clinical trials. The first trial, completed in April of this year, suggests the exoskeleton provides a “highly significant improvement” to mobility when worn and also, with time, improves the same patient’s ability to move without the exoskeleton. Only eight patients were a part of the study, however, so more work must be done to confirm HAL’s benefits.
Another civilian exoskeleton receiving attention is the ReWalk, a lower body exoskeleton that fits a role similar to the HAL. The ReWalk uses low-power leg motors to assist in mobility while offering all-day battery life. Unlike the HAL, the ReWalk must be used with canes, but it’s also further along in its development and has been approved in several countries. The ReWalk can be used for rehabilitation or can be purchased for personal use as an alternative to a wheelchair or powered scooter.
Batteries Not Included
FORTIS, which just began testing this year, is Lockheed-Martin’s newest exoskeleton. Though the first round of testing is being conducted by the Navy, this exoskeleton, unlike HULC, is meant only for civilian use. It reinforces the user’s body, reducing the strain of handling the heavy tools Navy mechanics often use to repair ships.
By wearing the FORTIS exoskeleton, operators can hold the weight of those heavy tools for extended periods of time with reduced fatigue. – Adam Miller, director of new initiatives, Lockheed-Martin
While it lacks batteries, FORTIS has impressive abilities. It can help users hold up to 36 pounds “effortlessly.” That may not sound like much at first, but remember that mechanics use such tools for hours every day. Any substantial weight can become tiring after a few minutes. The exoskeleton also helps transfer these loads to the ground, reducing strain on the user’s back and legs.
This type of exoskeleton, should it prove successful, could be a major boon to construction and industrial workers who have to lift modest loads repeatedly throughout the day. Work related injuries are still common in these fields and, over time, can greatly reduce quality of life for veterans of these fields.
FORTIS’ lack of power also reduces complexity and cost, making the idea more palatable for wide-scale deployment. With that said, though, FORTIS is still very early in its development; it was first announced just last month. Most other exoskeleton projects have been in development for years, and in some cases decades, so this project still has a way to go.
Still Human, But Better
The focus of the modern exoskeleton has shifted from enhancing strength and speed to enhancing endurance. In this sense the goal is not to make us far quicker or stronger than before but instead to make us more durable and improve our quality of life. While it’s not glamorous, this approach make sense; we conquered lifting heavy loads with the forklift.
Injury and exhaustion, though, are foes we’ve yet to defeat. A tired, injured soldier is likely to slow his entire unit and is less capable of responding to threats, and a 2013 estimate found on-the-job injuries cost up to $250 billion annually in the United States alone. Reducing strain and increasing endurance can benefit everyone from infantry in battle to healthcare workers moving patients between beds, so we’ll likely see exoskeletons continue this new approach in the coming decade. Exoskeletons won’t give us super-human strength or blazing speed – at least not any time soon. But they will help us live longer, better lives.
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