Soldiers someday could power their electronic devices for as long as 72 hours a stretch, with their footsteps providing the energy necessary to recharge batteries. A program underway at the Army Communications-Electronics Research, Development and Engineering Center (CERDEC) at Aberdeen Proving Ground, Md., is focused on conversion of soldiers’ steps – and other natural movements – into usable energy that could power the devices. Other equipment, such as night-vision goggles and radios – also could gain power through soldiers’ movements.
The development process is complicated, the design team said. Single motions such as footsteps alone are not enough to provide the necessary energy.
“The body does not produce enough excess motion energy at any one location, so we have to look at other areas of the body to find more energy. The ankle experiences the largest torque of any joint in your body, so it is a great source for an energy harvester,” said Nathan Sharpes, an engineer on the team.
Sharpes and his colleagues are working to incorporate pieces of equipment soldiers carry – such as boots and rucksacks – into the energy-generation process.
“We embedded an energy-harvesting mechanism into a combat boot heel insole, so that each time a soldier’s heel strikes it activates a generator, which spins to produce energy,” said Sharpes.
Engineers are working to improve the mechanism, so that it closely resembles a natural and comfortable step.
The rucksack design incorporates a device, called the Energy Harvesting Assault Pack (EHAP), which captures kinetic energy and converts it into a form usable energy.
Before any such devices become a part of the gear soldiers carry, they must not cause more problems than they solve. Soldiers already carry rucksacks that can weigh anywhere from 35 to 135 pounds. The engineering team knows that any energy-generating gear cannot add to that burden. The team is working to reduce the weight of prototype devices by half.
