The pit crews behind DARPA's robot race

From MIT professors to high school dropouts, humans are the driving force as the urban challenge draws closer. Photos: Teams tune up for Urban Challenge

People in downtown Ithaca, N.Y., got a glimpse this spring of the vehicular equivalent of a headless horseman--a Chevy Tahoe gutted and modified with computers, wire controls and sensors so that it can drive city streets by itself.

Isaac Miller, a doctoral student in mechanical engineering at Cornell University, said bystanders had one of several responses when they saw the Chevy shuttled through town on the way to a remote testing site: fear, disgust or appreciation. Like many other teams, Cornell is preparing for the Defense Advanced Research Projects Agency's Urban Challenge, a $2 million military-sponsored race of autonomous vehicles on city roads that's set for November 3.

Then there's the response Miller calls "the joke," for "when the onlooker laughs, thinking we're crackpots who just threw a bunch of crap on our car for no reason."

"Not surprisingly, we get very few looks of appreciation and quite a good number of fearful glances. The latter are especially commonplace in Ithaca and the surrounding area, where there are a good number of closet hippies and environmentalists unwilling to believe the Vietnam War is over," Miller wrote on the team's blog.

Pedestrians' incredulity aside, there are 53 teams working on autonomous vehicles that see the Urban Challenge as anything but a joke. The month of June is crucial for contestants because DARPA is making the rounds for so-called site visits, prequalification meetings in which the military's research and development arm will evaluate each team's viability to compete.

That means that to proceed in the challenge, each team's robot must prove basic navigation skills by driving on a prescribed course, and demonstrate traffic skills by negotiating a four-way intersection with two human-driven cars and another robotic vehicle. The feat, as well as the final race, will require the robots to sense its surroundings, discern moving objects from static ones, read their positions and predict behaviors, among other abilities. As one team leader put it: "It's a very unpredictable scenario."

The third of DARPA's robot races since 2004, the Urban Challenge will easily garner more attention than past races. That's largely because when the Stanford University Racing Team took first prize in the 2005 Grand Challenge, a 132-mile Nevada desert race of autonomous vehicles, more people began to take notice and envision a future of robotic vehicles--both in and outside the military's domain.

So when DARPA raised the stakes with an urban race, more universities, including the Massachusetts Institute of Technology, joined the fray. Computer scientists and engineers seem to agree that building artificially intelligent cars to navigate city streets is a much harder challenge than what was previously on the table. And as in any competition, every team has a slightly different story. Here are three teams to watch:

The heavy hitter
After passing over the two previous DARPA competitions, MIT, an academic stalwart in computer science and robotics, will try to play catch-up to race veterans like Stanford this year, according to John Leonard, one of the team's leaders. MIT joins the challenge with support from the university, Quanta Computer, Draper Laboratory and Ford Motor, which donated a Land Rover LR3 to the cause.

"We sort of like to pose ourselves challenge problems, and we want to push the field...and try to envision 10 years from now."
--John Leonard, team lead, MIT team

Leonard, associate professor in mechanical engineering at MIT, said the school's group is different than others because instead of employing one visionary leader--such as robotics professor Red Whittaker, who's led the Carnegie Mellon University team throughout the previous two DARPA challenges--it draws on the expertise of various faculty for "distributed decision making."

For example, Dave Barrett, a professor at Olin College, is building the vehicle with a team of students. Seth Teller, a professor in the electrical-engineering group at MIT, is leading perception development for the robot. And Jonathan How, in MIT's Department of Aeronautics and Astronautics, is working on the car's planning and control system.

Leonard said the robot is still a work in progress but that the team is making obvious safe bets in some cases and taking risks in other areas. For example, it is using an Electronic Mobility Controls drive-by-wire system, which Team Gray proved reliable in the 2005 Grand Challenge effort. But he said the team is being aggressive with a novel perception strategy. He said the robot will deploy tens of sensors to help perceive surroundings and infer the state of the world, but he did not go further into the technology.

Rather, Leonard gave a higher-level perspective on the contest.

"We sort of like to pose ourselves challenge problems, and we want to push the field...and try to envision 10 years from now. In that context, we thought urban driving was it," Leonard said. "We're drawn to it precisely for how hard we think it is."

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