Centibot army drills for action for the military

SAN JOSE, CALIF. — SAN JOSE, Calif. - When Randy Gobbel joined SRI International a year ago, one of the coolest things about his new job in the Engineering Building was the little red robots wandering the halls.

Wobbling around on three wheels and resembling mutant ladybugs, they would stop at Gobbel's open office door and silently peer inside. "Sometimes you feel like you just want to pet them," said Gobbel, a computer scientist who is working on a biochemical database.


But it wasn't a friendly visit. Though they looked like toys, they were working together to build a collective map, sending information back to a central computer. They were also on the lookout for objects interesting enough to warrant an alert to a human commander.

The Centibots are part of a military project funded by DARPA, the Pentagon's Defense Advanced Research Projects Agency. Working in teams of up to 100, they are designed to conduct surveillance in hazardous areas, spot intruders and find "objects of value" such as prisoners or wounded people. After a year and a half of development, the Centibots' creators say they are ready to show their stuff to their military backers. Last month, nearly 100 robots lined up in a hallway for a class picture, then were to spend the next few weeks in final testing before snuggling into bubble-wrap for the trip back east.


Charlie Ortiz, who oversees the Centibots project at SRI's Artificial Intelligence Center, said the effort represents a step forward in getting robots to work together autonomously and as a team. "They represent a major contribution in distributed robotics," he said.

Researchers have built robots that vacuum rooms, explore shipwrecks, manufacture microchips, imitate puppy dogs and fly around hunting for Osama bin Laden. But for the most part, modern robots act alone.

DARPA wanted machines that could coordinate with each other to create a map of an area. The Centibots communicate with a human commander who tells them where to search and reviews the information they send back. However, the commander doesn't need to give detailed instructions to each machine.

"They autonomously decide where to go," said Regis Vincent, a computer scientist who helped build the Centibots. "Nobody is controlling them."

SRI International, Stanford University, the University of Washington and ActivMedia, an Amherst, N.H.-based commercial robotics company, shared $2.2 million in DARPA funding to develop everything from a user interface to systems of navigation, communication and mapping.

The Centibots cost about $4,000 and are built from off-the-shelf components, including ordinary Wi-Fi cards for communicating with each other and cheap PC cameras that send images humans can interpret. Via Technologies, a Taiwanese company with operations in Fremont, Calif., supplied the motherboards. A Linux operating system manages 1.2 million lines of code, written in Java, C and C++.

Sitting in a windowless command center, surrounded by tables laden with computers and shelves packed with Centibots, Michael Eriksen, one of SRI's research engineers, put a handful of Centibots through their paces. As they trundled through the hallways, a map formed on his screen. He pressed some keys, and the map became a 3-D image.

Next, Eriksen put on a pair of glasses and selected Centibot No. 33. Streaming video showed him that the robot was "seeing" a hallway and a person's trouser legs.


Eriksen said the glasses could come in handy when the Centibots are used in real-world situations.

"A commander could tell the SWAT team, 'You are looking at this, and here is the guy we want, and this is what he is wearing,'" Eriksen said.

The Centibot researchers claim that the maps the robots create are correct within a couple of centimeters. The robots can also find and identify an object, recognize each other and spot an intruder by separating moving objects from stationary ones.

Though their skills are somewhat rudimentary - the object they best recognize is a big pink ball, and they find each other by zeroing in on highly reflective material - they've come a long way during the past 11 months.

Ortiz recalled when the Centibots were first turned loose last January, they kept bumping into each other. Equipped with sonar sensors that enabled them to identify obstacles, they would see another Centibot and try to move out of the way. But like two people trying to walk around each other, the Centibots moved in the same direction and collided.

More code had to be written so that two Centibots looking at the same pink ball would realize they were seeing one object and not two.


Now, the researchers say they believe they have succeeded in imbuing the machines with a new level of artificial intelligence.

And even if the Centibots don't have human brain cells, the computer scientists in the Engineering Building have become attached to the hallway wanderers. They'll miss the robots when they're gone.