Drive time

The Defense Advanced Research Projects Agency's competition for autonomous vehicles has seen great leaps forward in its first two incarnations. This year, the ride could get rather bumpy, as the Grand Challenge moves from the expanses of the desert to the mean streets of the city.

The competition, called the Urban Challenge for 2007, is no mere sporting event. DARPA's goal is to use the challenge to help develop technologies for self-guiding military vehicles that could reduce the deadly toll of vehicular-related battlefield casualties among U.S. military personnel.

Approximately half the U.S. soldiers killed to date in Iraq have died in enemy attacks on vehicles, whether by live enemy fire or by improvised explosive devices or, to a lesser extent, in vehicular accidents.

Based on results from the two previous Grand Challenges and a preliminary look at the entrants in DARPA's Urban Challenge contest now under way, 'we think that over time we will be able to build vehicles that will be able to drive as well as humans in certain situations,' said Norman Whitaker, program manager for DARPA's Urban Challenge.

In May, DARPA trimmed the roster of teams competing in the Urban Challenge from 89 to 53 and will further narrow the field to 30 semifinalists this week based on scores issued during site visits DARPA officials have been conducting since May. The agency also will name this week the location of the competition's Qualification Event scheduled for Oct. 26 to 31 and the location for the final contest Nov. 3.

To date, DARPA has said only that both events would take place in the western United States, although its placement in a simulated urban combat zone has become the theme of this year's contest and considerably upped the ante for the level of vehicle proficiency that will be required to successfully complete the contest's 60-mile course in six hours.

The complexities of a city environment and the introduction this year of other moving vehicles along the course increases exponentially the sophistication of the sensing, data processing and guidance technologies required, Whitaker said.

DARPA's goal in its successive challenges is to raise the bar each time, he said, although the addition of moving traffic represents the biggest obstacle ever added to the contest.

The first Grand Challenge in 2004 ran over a 142-mile course in the desert, but the competition looked more like the Keystone Cops than Knight Rider ' no vehicle made it past the eight-mile mark. Still, DARPA officials said they saw promise, which came to fruition in 2005, when four vehicles covered a 132-mile desert course. With those results, the decision was made to take the Grand Challenge downtown.

With an urban setting and traffic, vehicles 'have to make decisions fast, so we've speeded up the timeframe' in which vehicles must receive sensor data, process it and respond, all without human intervention, Whitaker said. 'As usual, we've taken it to the nth degree and said we want full autonomy. By [asking for an extreme], we get a lot of the middle ground covered.'

The placement of this year's contest in a dynamic setting creates challenges unheard of in previous challenges and requires technological advancements that will bring self-guided vehicles to a near reality, participants say.

'This year we have moving objectives and that dynamic interaction is new and very difficult,' said Gary Schmiedel, vice president of the advanced product engineering group at Oshkosh Truck, one of the corporate entrants in this year's Urban Challenge and one of the teams that successfully completed the 132-mile course in 2005. 'This brings us much closer to a real-world application of the technology and means that we have to build a truck that's as versatile as you or I would be.'

At the level of sophistication that will be required in this year's contest, 'this is really a software competition, not a hardware competition,' said David Stavens, a doctoral candidate at Stanford University who's working on Stanford's entry in the Urban Challenge and was a co-creator of Stanley, the modified Volkswagen Touareg sport utility vehicle that won DARPA's 2005 Grand Challenge for Stanford University.

The Stanford team, consequently, is spending much of its time this year working on probabilistic algorithms and machine learning capabilities and is tackling the problem with help from the Stanford Artificial Intelligence Laboratory, Stavens said. Probabilistic algorthms will help this year's Stanford entry, Junior, a Volkswagen Passat station wagon, deal with uncertainties along the course, while machine learning will enable the team to program the car with human-like driving skills.

'By driving other roads, you can gain enough knowledge that the robot will be able to handle the Urban Challenge course just fine,' Stavens said. 'This is a very rich subset of the skills that you and I would use when we jump in our own cars and go driving, but this type of technology can save our soldiers' lives in the battlefield and save lives in the civilian world.'

After this year's challenge, DARPA will evaluate whether the contests have advanced the technology enough to make commercial production of autonomous vehicles for the military feasible and economically practical, Whitaker said. After an experiment along the lines of the challenges, 'there's an intermediate phase before [the military] goes out and starts buying systems. It could also be that we'll need to see more work on the commercial side,' he said.