Researchers Develop Power-Producing Backpack

Sept. 8, 2005 — -- Relief workers wandering through the hurricane-damaged areas of the Gulf Coast carry a heavy burden -- literally.

In addition to food, potable water, medical supplies, flashlights, radios and other electronic gear such as GPS satellite receivers, some crews -- rescue teams and National Guard soldiers, for example -- must carry other weighty tools while on duty.

Researchers say shouldering that load may someday be helpful in another way: To help produce electricity to run the workers' high-tech gear or to provide power in areas where there is none.

Researchers at the University of Pennsylvania have developed a new type of backpack that actually generates electricity as a load-bearer walks. Lawrence C. Rome, a professor at the university's Department of Biology and the lead researcher of the project, says the concept behind the device is pure simplicity.

"When you walk, your hips move about five to seven centimeters [about two to three inches] vertically," says Rome. "That's because you have a straight leg, that when you plant it on the ground, it's actually lifting you -- sort of like when a pole-vaulter plants his pole and then is lifted up -- in an arc as you move forward."

Most people don't notice those tiny up-and-down motions while walking. But Rome did and he set out with his research team -- Louis Flynn, an engineer, and postdoctoral fellows Evan M. Goldman and Taeseung D. Yoo -- to turn those small oscillations into pure electrical energy.

The team's prototype Suspended-load Backpack looks similar to any rigid-frame pack commonly used by campers, hikers and soldiers.

But as the name implies, the portion of the backpack that actually carries the wearer's cargo is suspended on a "load plate." The plate itself is connected to the frame by a series of vertical springs, allowing it to slide freely. Also on the plate is a "rack," or small row of teeth, which mates to a gear attached to a tiny generator mounted on the rigid frame.