The search has been on for years for a way to take the donkey work out of carrying heavy packs and equipment. In September researchers in the Media Lab’s Biomechatronics Group at the Massachusetts Institute of Technology (MIT) announced that their exoskeleton device almost fits the bill.
The technology has the potential for enabling soldiers, wildfire fighters and rescue and disaster relief personnel to carry heavy loads of equipment and supplies over all types of terrain. While ergonomic features of the design could lessen the likelihood of leg or back injury, the devices could boost the weight a person can carry and reduce the perceived level of difficulty of carrying a heavy load.
The MIT researchers reported in the September issue of the International Journal of Humanoid Robotics that their prototype can successfully support 80 percent of an 80-pound load carried on a person’s back.
The user places 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 small external power input of only one watt.
There is a catch. The prototype is limited because it impedes the natural walking gait of the person wearing it. 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.
The MIT 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 Conor Walsh, a graduate student who worked on the project, is that the team’s spring-based, low-energy design shows promise.
MIT’s exoskeleton is not the only wearable strength and endurance-enhancing device under development. The others also report limitations.
A prototype developed in 2004 by researchers at the Robotics and Human Engineering Laboratory of the University of California Berkeley, called the Berkeley Lower Extremity Exoskeleton (BLEEX), has promising features but it is bulky, heavy and noisy. In the UC Berkeley experiments, the human pilot moved about a room wearing the a 70-pound backpack while feeling as if he were lugging a mere 5 pounds, but the device weighs 100 pounds.
The focus of the BLEEX team has turned to miniaturization of the components. The researchers are developing a quieter, more powerful engine, and a faster, more intelligent controller that will enable the exoskeleton to carry loads up to 120 pounds.
Sources: Massachusetts Institute of Technology; University of California Berkeley