The DARPA Urban Challenge
was held on November 3, 2007, at the former George AFB in Victorville, Calif.
Building on the success of the 2004 and
2005 Grand Challenges, this event
required teams to build an autonomous vehicle capable of driving in traffic,
performing complex maneuvers such as merging, passing, parking and negotiating
intersections. This event was truly groundbreaking as the first time autonomous
vehicles have interacted with both manned and unmanned vehicle traffic in an
urban environment.
Teams from around the world were whittled down through a series
of qualifying steps, beginning with technical papers and videos, then advancing
to actual vehicle testing at team sites. Of the 89 teams to initially apply, 35
teams were invited to the
National Qualification Event (NQE), a rigorous
eight-day vehicle testing period. The NQE was co-located with the Final Event
in Victorville, CA. DARPA transformed the roads of the former George AFB into an
autonomous vehicle testing ground, laying over four miles of protective k-rail
barriers in creating multiple test courses.
An autonomous ground vehicle is a vehicle that navigates and drives entirely on
its own with no human driver and no remote control. Through the use of various
sensors and positioning systems, the vehicle determines all the characteristics
of its environment required to enable it to carry out the task it has been
assigned.
To see videos and pictures of the event, please
visit the Gallery.
National
Qualification Event
The NQE for the Urban Challenge was divided into three separate test areas, each
with its own flavor and set of challenges:
The NQE A
test course required robots to safely merge into and out of two-way traffic in a
tight, circulating course. Needless to say, this led to some hair-raising
moments for some of the traffic drivers. Besides the complex timing and scoring
being recorded by course officials, traffic drivers would alert officials to
aggressive behavior with an ever-popular horn blast. Amazingly, in eight days
of testing, only one traffic vehicle was actually struck by a robotic vehicle, a
testament to the progress of the teams and DARPA’s focus on safety.
The meandering NQE B course tested
robots on their ability to stay within a lane as they traversed this 2.8-mile
course. One section, affectionately termed “The Gauntlet” required the robots to
delicately maneuver through a series of parallel parked cars and road obstacles.
A final test on the NQE B course required the robots to find an assigned parking spot between adjacent parked
cars, then safely pull into and back out of the spot before proceeding on its
mission.
NQE C was traffic intensive,
consisting of a series of four-way stop intersections for the robot to
negotiate, each with its own arrangement of traffic. Robots had to recognize the
other vehicles at these intersections, determine the order of precedence and
then safely proceed through the intersection when it was their turn. For the
second half of the NQE C course, various road blocks were emplaced and the
robots were tested on their ability to recognize the road block, execute a
U-turn and dynamically replan a new route to complete their mission.
Final Event
After tallying all of the NQE scores, DARPA
announced on November 1, 2007, that
11 teams would be competing in the Final
Event. And so at sunrise on November 3, in front of a crowd of thousands on hand
to witness history being made, Dr. Tether, DARPA Director, raised the
green flag and the race was on. One by one, all 11 finalist robots were released
from their starting chutes, followed by a chase vehicle equipped with an
emergency stop control.
The course for the final event was communicated to
the teams in the form of two
files, analogous to a map and a
specific mission. Upon announcing the finalist selections on November 1, teams
were given the ‘map’ file of the final course (Route
Network Definition File). However, each team didn’t receive their
Mission Definition File,
which lists the order of checkpoints they had to visit, until five
minutes before they launched on race day. With this approach, the teams had no a
priori knowledge of their missions, creating a truly autonomous driving test.
Thirty manned traffic vehicles
were also released onto the course to increase traffic density. This fleet of
Ford Tauruses were retrofitted with safety cages, race seats, fire systems,
radios and tracking systems,
and were driven by professional drivers. In all, over 50 vehicles, both manned and
unmanned, were navigating the city streets simultaneously during the final event.
DARPA staff were scattered throughout the course
serving as safety officials, noting any errant or unsafe behaviors which would
eventually be counted in a team’s final score. The Command Operations Center (COC)
served as the central hub for all race monitoring, where DARPA staff tracked all
vehicles, initiating coursewide emergency-stop commands to the robots as
necessary.
After strong starts by all the finalists, by mid-morning almost half of the
field had been removed from the race for a variety of reasons. Terramax, a
returning crowd favorite, went awry in a parking lot, and was stopped moments
before entering the old commissary building. Team UCF decided to take a break
and pulled off the road and into a carport before being removed from the race by
officials.
Despite these hiccups, six teams emerged as strong
contenders as they methodically picked through their missions. Early afternoon
brought the first true accident of the day when Cornell and MIT bumped sides at
low speed as they tried to share a lane. The robots were separated and allowed
to resume their missions.
Highlight videos and pictures of the NQE and Final
Event can be found in the
Gallery.
DARPA broadcasted the event live to the world over the internet and had a
huge viewing audience in the event tent, where live footage
was projected on
giant screens.
As the day wore on, it became apparent to all that this race was going to have finishers,
and that it was going to be a close one. At 1:43 pm, Stanford’s entry, “Junior” crossed
the finish line first with a run-time of just over four hours. A minute later, Tartan Racing’s
“Boss” crossed the finish line. It was a scene that would be repeated over and over as six robots
eventually crossed the finish line, an astounding feat for the teams and proving to the world that
autonomous urban driving could become a reality.
Awards Ceremony
This event was not just a timed race however –
robots were also being judged on their ability to follow
California driving
rules. DARPA officials pored through reams of data throughout the night,
analyzing each team’s infractions and elapsed run times.
At the awards ceremony the next morning,
DARPA announced the winning order: