Robotic 'exoskeletons' could help soldiers bear heavier loads.

• Author: Pappalardo, Joe

Researchers are edging closer to fielding a gas-powered system that will permit soldiers to effortlessly carry hundreds of pounds of equipment on the battlefield.

The program, sponsored by the Defense Advanced Research Projects Agency (DARPA), is paving the way for robotically enhanced soldiers, but not necessarily futuristic front-line warriors, caution scientists.

Contractors and the program manager of the exoskeletons for human performance augmentation (EHPA) said that, while the option for battle-ready, wearable robotic suits remains open, the system that is being currently pursued is aimed at allowing soldiers to tote enormous loads.

"This thing is useful for carrying payload," said DARPA project manager John Main. "It could be 200 pounds of food, or it could be 200 pounds of body armor."

The overall goal of EHPA is to develop devices that increase the speed, strength and endurance of soldiers in combat environments. When EHPA was launched in 2000, visions of massive power suits that propelled wearers over buildings and through walls--mainly products of the fertile imagination of science fiction writer Robert Heinlein--leapt into people's minds. The reality may be more mundane, but the challenge remains enormous.

"This is a fairly boring transportation program," Main said, with a small grin. "We're not jumping over buildings. We're getting into rough terrain that is denied to Humvees."

In 2001, six contractors were left to pursue the development of self-powered, controlled, and wearable strength augmentation systems. The first challenge was proving that actuators--machine muscle--and high-density, man-portable energy sources were feasible.

In the fall of 2003, two contractors the University of California-Berkeley and Sarcos Research Corp.--were chosen to create the system. Locust USA Inc. of Miami and TIAX LLC, of Cambridge, Mass., are working on the power source.

The words off-the-shelf are not used much in the exoskeleton program, Main said, since everything is being built and optimized specifically for the product. "Every part going into the exoskeleton needs to be designed from the ground up," be said.

It may be too early to plan around real-world applications, but military personnel are watching the development of the project. Those who handle logistics envision exoskeletons loading trucks, while infantry commanders see the extra weight dedicated to shielding, Main noted.

"If you think about this in terms of airplanes, we're about...