Fighting robots — once the stuff of Hollywood sci-fi flicks — could be making their way onto battlefields to help the military within a matter of years.

"We've always talked about robots doing the dangerous, dirty and dull jobs," said Chuck Thorpe, director of the Robotics Institute at Carnegie Mellon University. "Certainly a lot of those jobs are to be found in the military, where you'd like to have eyes and ears and hands and legs on the ground, but not risk people."

With a growing fleet of high-flying drone aircraft, the U.S. military has already taken steps toward a Phantom Menace-style army. The Predator drone — remotely operated by a human pilot — made headlines last year when it was used to locate fleeing Taliban and Al Qaeda fighters and to map unknown terrain in Afghanistan.

Yet the Predator drones are not actually robots because they rely on human beings to do their thinking. The idea of an autonomous mechanism is another step entirely.

But it's a step that hydraulically-powered, steel-sheathed feet could be taking sooner than you might think.

At General Dynamics, the Army has been in contract for years to develop robots that will be able to make the military a stronger, faster, more efficient fighting force.

"[With robots] you've got a tremendous capability to keep your troops out of harm's way," spokesman Peter Keating said from company headquarters in Sterling Heights, Mich. "Robots are cheaper and more expendable than human beings."

General Dynamics is working on four projects designing various robots for Army use, Keating said.

The first project seeks to develop sentinel robots that would be stationed inside or outside buildings. Equipped with heat, motion, chemical, biological, or sound sensors, or a combination thereof, they could make the dozing guard a relic of the past.

Another project is developing artificial intelligence to overcome obstacles that have, so far, confounded experts — how to get a robot to reliably climb stairs, negotiate a ditch or identify barriers it can neither cross nor climb.

"The Army could plot a course for the robot to go out as a scout vehicle or to carry medical supplies or rations," Keating said. "But if the robot goes on the route and realizes, 'Hey, there's a problem, the route's impassible, the bridge is blown up or flooded,' it would be able to tell, based on the sensors it had, infrared or acoustic, that it can't get through and get started moving on a different course."

The third project would develop robots for patrol areas, even quietly following intruders if ordered to by a remote human supervisor. And the final project would hash out ways the other three could be integrated and applied to military situations.

The Navy, meanwhile, is exploring "robo-crabs," eight-legged, lobster-like robots measuring 2.5 feet and weighing 10 pounds that could be used to find and detonate underwater mines, The Wall Street Journal reported.

Robots could also be used for civilian purposes, Thorpe said.

"Easy examples are the rescue efforts at the World Trade Center," he said. "A lot of brave people risked their lives going through that rubble. If we had the next generation of robots, we could have done a lot of that without people getting in harm's way."

Or they could clear out landmines in formerly war-torn countries, Thorpe said.

"Huge areas in Cambodia have landmines which are not really a military issue," he said. "Right now the military can get away with clearing a narrow strip through a field of landmines. But the poor farmers need the whole field."

But of course there are some things robots might never be able to do.

"Robots don't have the kind of common sense and decision-making ability to tell between someone surrendering and someone approaching with hostile intent," Thorpe said. "That's why we don't want robots carrying their own weapons and making firing decisions."

Keating said that, so far, it's impossible to make robots completely independent of humans on the battlefield.

But the day is coming when American soldiers will fight alongside robotic comrades — even if those robots aren't carrying weapons, Thorpe said.

"The military has shrunk drastically and has realized that there are more and more kinds of conflicts out there that heavy tanks aren't prepared for," he said. "And the military has been very receptive to the idea of a faster-moving, lighter force that puts things in harm's way, not people."