The warfighter who carries up to 100 pounds of equipment on his back is expected to get relief from the cumbersome weight. The Defense Advanced Research Projects Agency’s (DARPA) semiautonomous Legged Squad Support System (LS3) robot will carry 400 pounds of warfighter equipment, walk 20 miles at a time, and act as an auxiliary power source for troops to recharge batteries for radios and handheld devices while on patrol.

Now in trials, the “pack mule” robot might have numerous functions, but its primary responsibility is to support the warfighter. And as the weight of their equipment has increased, so have instances of fatigue, physical strain, and degraded performance. Reducing the load warfighters carry has become a major point for research and development because the increasing weight of equipment has a negative effect on warfighter readiness.

DARPA’s five-year, $54 million LS3 project began in September 2009, and now is undergoing trials in the field. The LS3 must become familiar with different types of terrain, from wooded areas to deserts, and with varying weather conditions such as rain and snow. The LS3 prototype completed its first outdoor assessment in January, demonstrating its mobility by climbing and descending a hill and exercising its perception capabilities.

The robot’s sensors allow it to navigate around obstacles at night, maneuver in urban settings, respond to voice commands, and gauge distances and directions. The LS3 also can distinguish different forms of vegetation when walking through fields and around bushes. With the ability to avoid logs and rocks, the LS3’s intelligent foot placement on rough terrain is a key element.

The vision is a trained animal and its handler. A squad leader would learn 10 basic commands to tell the robot to do such things as stop, sit, follow him tightly, follow him on the corridor, and go to specific coordinates.