Stronger, faster and harder is the promise of a new exoskeleton developed by Lockheed Martin for U.S. soldiers. Dubbed the Human Universal Load Carrier, or HULC, the device helps a soldier carry up to 200 pounds at a top speed of 10 mph.
"The soldier has the feeling of maybe an extra five to 10 pounds," said Doug Medcalf, Business Development Manager at Lockheed Martin. Today some soldiers are carrying loads of up to 130 pounds into combat.
Unlike most exoskeletons built to boost human ability, the HULC, which Medcalf says does not owe its name to the popular green comic book character, isn't limited to the length of its power cable.
The titanium HULC instead runs on a four lithium ion batteries nestled into the small of a soldier's back. Eight batteries can power the HULC on missions up to 96 hours.
The HULC is easy to put on, its makers report. It arrives folded into a small package. The soldier stretches a leg out and steps into foot beds underneath the boot. Straps wrap around the thighs, waist and shoulders.
The foot pads ensure that the weight from the soldier's load rests directly on the ground, not on the soldier's body. Inside the foot pads are pressure sensors that relay information about the speed and walking style of the soldier to an onboard computer. The computer's artificial intelligence moves the hydraulic system to amplify and enhance that movement.
The HULC allows a soldier to walk, run, kneel and crawl, among other things. It can impede other movements however, but if a soldier comes under fire and needs more flexibility, the HULC can be removed in about 30 seconds.
Wounded soldiers could be evacuated faster and easier by other HULC-equipped soldiers, Lockheed says. Retreating soldiers could deny the enemy equipment that today would have to be left behind because of its heft.
The HULC comes at a critical time. U.S. Army reports show that 20,000 soldiers are classified as "non-deployable." Half of those were injured during battle. The other half cannot be deployed because of physical problems, such as an inability to haul heavy loads.
HULC wasn't created to reduce injuries, but "if it does reduces injuries along the way, that is a positive for the war fighter," said Medcalf.
Medcalf said they could design an exoskeleton that could carry more weight, but they don't expect their customers will need to carry more than 200 pounds at once.
As a product of millions of years of evolution, the human body is naturally good at moving around, said Aaron Dollar, a professor of mechanical engineering at Yale University. Any attempt to improve on nature's design is a difficult engineering challenge.
"Walking is one of the things that the human body is most efficient at," said Dollar. "Anytime something is really good, like human walking, it is hard to improve it."