From Science Fiction to Science Fact, 'Exoskeleton' Could Lighten the Load
Researchers in the Massachusetts Institute of Technology (MIT) Media Lab's Biomechatronics Group recently announced that they have created a device to lighten the burden for soldiers and others who carry heavy packs and equipment.
Their invention, known as an exoskeleton, transfers much of the weight of a heavy backpack directly to the ground, effectively taking a load off the back of the person wearing the device.
In the September issue of the International Journal of Humanoid Robotics, the researchers report that their prototype can successfully take on 80 percent of an 80-pound load carried on a person's back, but there's one catch, it impedes the natural walking gait of the person wearing it.
"You can definitely tell it's affecting your gait," said Conor Walsh, a graduate student who worked on the project. "You do feel it taking the load off and you definitely feel less stress on your upper body."
When the MIT researchers tested their device, they found that although the load borne by the wearer's back was lightened, the person carrying the load had to consume 10 percent more oxygen than normal, because of the extra effort to compensate for the gait interference.
Eventually, exoskeleton devices could boost the weight that a person can carry, lessen the likelihood of leg or back injury, and reduce the perceived level of difficulty of carrying a heavy load.
To wear the exoskeleton the user must place his or her feet in boots attached to a series of tubes that run up the leg to the backpack and transfer the weight of the backpack to the ground. Springs at the ankle and hip and a damping device at the knee allow the device to approximate the walking motion of a human leg, with a very small external power input (one watt, compared to similar devices in development that use up to 3,000 watts).
The team hopes to revise the design so the exoskeleton more closely mimics the movement of a human leg, allowing for more normal walking motion. The most important result of this study, says Walsh, is that the team's spring-based, low-energy design shows promise. "This is the first time that it has been tested," he said. "We didn't know what to expect."