Taking It to the Streets

Article excerpt

DARPA's Latest Robotic Competition Focuses on Urban Environment

In the predawn hours of Saturday, November 3, 2007, the former George Air Force Base, in Victorville, Calif., was a beehive of activity as industry and academia teams made a flurry of ?last-minute adjustments to nearly a dozen of the most unusual vehicle platforms to ever run in a milifary competition.

Called Urban Challenge, the event marked the third major robotic competition organized and conducted by the Defense Advanced Research Projects Agency (DARPA).

"We are the central research organization for the Department of Defense, conducting leading-edge and far-out projects that push the boundaries of technology," explained Dr. Norman Whitaker, DARPA's program manager for Urban Challenge. "We've been looking at the problem of protecting people on the battlefield for quite a while now. Unmanned aerial vehicles have been very successful; they are used extensively in the military context. We're now looking at 'the ground problem' in terms of unmanned ground vehicles."

DARPA's first significant competition focused on the ground problem was conducted in March 2004. Called Grand Challenge, the event included a 142-mile desert course between Barstow, Calif., and Primm, Nev. Fifteen autonomous ground vehicles attempted the course, but the best performance only stretched seven miles, and the $1 million cash prize went unclaimed.

A second Grand Challenge, held 19 months later, showed a quantum leap in robotic vehicle technologies. Similar in scope to the first, the October 2005 event required vehicles to complete a 132-mile desert route in southern Nevada in less than 10 hours.

"We had 195 entrants and had five finishers cross 132 miles of desert," Whitaker said. "A tremendous amount of energy was built as a result of that event."

"These are vehicles that are fully self-contained," he noted. "You put them on the starting line, push the button and they go. There's no remote control. It is totally under the control of its own computer."

In determining the path forward, DARPA planners shifted focus from an autonomous cross-country desert venue to a course that would introduce aspects of modern urban operational environments.

"I was out here in January when we discovered this area as a place where we could run vehicles down the street; if they crashed into a building or ran off the road, they would not cause any damage," Whitaker said. "This area is a closed military base that is used for MOUT (military operations in urban terrain) training, so it closely resembles the type of environment our troops face overseas."

Initial DARPA solicitations drew 89 applicants for Urban Challenge, a figure that was later reduced to 36 after DARPA site visits and analysis.

"For the past week or so, we have had 35 teams here [one of the 36 selected semifinalists subsequently withdrew] at the former George Air Force Base, where we have been testing them on the rudiments of urban driving," Whitaker said. "The problem of urban driving is difficult because basically every mission ends or begins someplace where there are people, vehicles, buildings and roads nearby. In order to build truly safe systems, we decided to provide metrics by which they would be judged."

He added that those performance metrics were roughly based on the California Driver Handbook.

"We have taken that handbook and looked at what human drivers were required to do: 15-year-olds-how well can they drive? And we have tried to impose that level of skill on the robots," he said.

Once at the Victorville site, the 35 teams participated in a national qualification event (NQE) from October 26-31.

Whitaker explained that the NQE involved different test areas.

"One test area included left turns across traffic. The vehicle had to be able to pull into a busy two-lane road with traffic coming in both directions. It was challenging for a vehicle to be looking in both directions at the same time, predicting when the other vehicles would arrive at the intersection and then determining when it was safe to pull in. …