THE DAY COULD SOON come when autonomous robots roam the planet in search of raw biomass to consume for power. Such is the vision of the Energetically Autonomous Tactical Robot system, although you can call it EATR. “Imagine the robot in the movie WALL-E—but instead of just compacting trash, it's combusting trash for electrical energy,” says Robert Finkelstein, director of the Intelligent Systems Laboratory in the Clark School of Engineering at the University of Maryland and president of Robotic Technology, the company developing EATR. The robot uses intelligent software to visually distinguish its preferential “food”—wood chips, dried leaves and other vegetative biomass—from nonuseful materials such as rocks, animal matter and metal. Then, using a robotic arm guided by a close-range laser-based guidance system, EATR grabs the vegetation and places it into a hopper leading to an external-combustion engine, which charges an onboard battery.