Carnegie Mellon University rolled out its latest unmanned combat prototype vehicle yesterday in a display of speed and mobility that would make a monster truck show look tame.

	Darrell Sapp, Post-Gazette
	The newly unveiled autonomous robotic vehicle "Crusher" shows how it can take on difficult terrain, at the National Robotics Engineering Center in Lawrenceville. It weights 6.5 tons. NREC is part of the Robotics Institute in Carnegie Mellon University's School of Computer Science. The work is funded by the U.S. Army and the Defense Advanced Research Projects Agency (DARPA).

The National Robotics Engineering Center, part of the CMU Robotics Institute, unveiled Crusher, a six-wheeled vehicle billed as leaner and more agile than its predecessor, Spinner, but also more durable and able to handle a heavier payload.

Two Crusher vehicles paraded slowly before an audience at the center's headquarters in Lawrenceville before one of them headed outside to clamber nimbly over logs and other obstacles, a quality that earned it its name. A video presentation showed the vehicle speeding through rough terrain.

The center is the prime contractor for Crusher, a project funded by the Army and the Pentagon's Defense Advanced Research Projects Agency, known as DARPA.

Since 2001, DARPA has awarded the center more than $35 million for the development of Crusher, its predecessors and autonomous navigation technology, which allows the vehicles to drive by themselves without human supervision.

Eventually, the military hopes to use large unmanned vehicles for reconnaissance, re-supply of troops or other needs -- the "dull, dirty and dangerous tasks that can be better accomplished by machines," said Steve Welby, director of DARPA's tactical technology office.

Unlike Spinner, Crusher is not designed to keep operating if it flips over.

The Crusher design team concluded that abandoning the capacity for inverted operation, while maintaining some of Spinner's other design characteristics, would offer dramatic reductions in weight, complexity and cost. At 6.5 tons, Crusher is nearly one-third lighter than its predecessor, but can comfortably handle a four-ton payload.

Features include a light, strong frame made of aluminum and titanium and a suspension system that allows the vehicle to either rest on its belly or have 30 inches of ground clearance, allowing for greater ease in clearing obstacles. Electric motors in each of the wheels allow them to run at different speeds.

Still, "you hit things you don't expect," said John Bares, the center's director. So Crusher is equipped with an energy-absorbing nose and a protective plate beneath the vehicle, with blocks of rubber around the chassis to absorb shock.

To provide maximum power with minimum weight, Crusher has a turbo-diesel engine that recharges the vehicle's batteries. With the engine turned off, Crusher can operate quietly for two miles or more on battery power alone.

At yesterday's demonstration, operators directed both Crusher vehicles using remote controls. But plans calls for outfitting Crusher later this year with autonomous navigation that will allow the vehicle to find its own way to a specified location, adjusting for obstacles it may encounter.

Testing will be done in Colorado later this summer.