Autonomy. Lawrence Burns
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Название: Autonomy
Автор: Lawrence Burns
Издательство: HarperCollins
Жанр: Программы
isbn: 9780008302085
isbn:
Minutes later, Red Team heard from a race organizer that something was wrong with Sandstorm. The hay bale the robot had run over just after the start turned out to reflect an ongoing problem. Perhaps because its sensors hadn’t been calibrated properly, perhaps because the main LIDAR’s replacement unit scanned at a much slower rate than the original, Sandstorm consistently appeared to think that it was a foot or two to the left or right of where it actually was. The Humvee drove over a fencepost, then another and a third. Some miles later, the vehicle swung itself into a curve, a particularly tricky one given the inside edge was separated from a steep drop-off by only a knee-high berm. As Urmson and Peterson intended, Sandstorm slowed down as the road turned. But the robot was a foot or two to the left from where it should have been. As a result, the left-most tires climbed up the berm, then dropped down the steep inside ledge. Sandstorm was now stuck on its belly—what Urmson called “high-centering.”
Things quickly grew worse. Sensing Sandstorm wasn’t moving, the speed control system kicked in, directing more power to the engine. One of the tires hanging over the other side of the berm was situated just high enough off the ground that it could still touch the Mojave sand. The friction heated up the rubber until it smoked and eventually burst into flames. The robot’s progress was over 7.3 miles from its start.
The media used Sandstorm’s flame-out as a metaphor for the entire event. The number-two entrant, SciAutonics II, also got stuck on a low hill of earth. Dave Hall’s Toyota Tundra became confused by a small rock. The UCLA entry, Golem Group, stalled out when a safety device prevented its engine from accelerating enough to get up an incline. And TerraMax, the 32,000-pound monster truck known for its brute force approach, ended up halted when a pair of tumbleweeds it incorrectly considered immovable obstacles blew ahead and behind it. And those were the best-performing vehicles.
The result put DARPA director Tony Tether in a tough spot. At the other end of the race course, in Primm, Nevada, was a tent full of reporters who had traveled across the country to file stories on the race winner. Tether figured he was going to get killed by the press—an expectation that proved right. “DARPA’s Debacle in the Desert,” went one headline. The gist of the stories portrayed DARPA as an out-of-touch government bureaucracy that had wasted money staging a fool’s errand. So to distract them, Tether took the stage and announced a second race, to be held in a year or so, with a doubling of the 2004 race’s purse, to $2 million.
The only way to prove you’re a good sport is to lose.
—ERNIE BANKS
Red Whittaker started planning for the second race even before Sandstorm returned to Pittsburgh from the first. Through his repeated entreaties for sponsorship, Whittaker had developed a relationship with AM General, the company that manufactured the Humvee. Now Whittaker thought he could convince the executives to donate an additional vehicle for Red Team to use in the next challenge—if the executive team would only witness a demonstration of Sandstorm’s capabilities.
Several days after the first challenge, Whittaker, Spiker and Peterson arrived with Sandstorm at the AM General campus in South Bend, Indiana, to conduct that demonstration. Spiker and Peterson stayed outside and set up the robot on an obstacle course the Humvee manufacturer maintained to educate new owners on the capabilities of their vehicles.
One element of the obstacle course was a concrete tabletop structure, maybe eighteen inches off the ground. Peterson and Spiker wondered whether Sandstorm could drive itself up and onto the obstacle. Moments later, rather than creeping toward the tabletop, as Spiker and Peterson had intended, Sandstorm took off toward it at high speed.
A kill switch was designed to deactivate Sandstorm if it ever did anything unpredictable. Trouble was, the kill switch had about a two-second delay. Spiker pressed the switch, but Sandstorm hit the tabletop before the command took effect. The front wheels bounced the front end into the air. The rear wheels hit the tabletop and bounced up the Humvee’s back end. For a moment the entire vehicle was airborne. Then the front end nose-dived with a violent slam against the concrete.
That’s when the kill switch disabled the vehicle.
Spiker and Peterson rushed to assess the damage. Whittaker was in a nearby building conducting his presentation for AM General executives on Red Team, and the wonderful capabilities of the robot they’d developed. Outside, Spiker and Peterson discovered the impact of Sandstorm on the tabletop had crushed an engine-compartment coolant tank. Once that was repaired, they set up Sandstorm on a section of clear road and activated the giant robot to test it. Immediately the front wheels turned to the right. That shouldn’t have happened. “Kill kill kill!” Spiker shouted to Peterson. With a snort of exhaust, Sandstorm accelerated right off the road and straight into the building where Whittaker was talking to the AM General executives. The impact of the Humvee against the wall shook the entire structure.
Later, Spiker figured out that the tabletop collision had detached a steering position sensor from its mooring—which, in turn, caused the second accident. But it turned out not to have mattered. Whittaker and the AM General executives rushed from the building to investigate the source of the impact. Spiker figured the sponsorship bid was toast. But as the execs surveyed the scene of the accident, Spiker realized his fears were groundless.
“Unflinching grace” is the way Whittaker characterizes the AM General execs’ reactions, portraying them as “great hosts who don’t fuss over a dropped fork or spilled water.” The executives saw themselves as manufacturing a vehicle designed to push the bounds of what an automobile could do—and so, in its own way, did the Red Team. Of course they would sponsor Whittaker’s team. “We’ll give you two Humvees,” one of the AM General execs proclaimed. “Just be careful.”
Some months later, in the summer of 2004, a computer scientist named Sebastian Thrun listened to a presentation about the first DARPA Grand Challenge in a seminar room at Stanford University. Thrun had recently moved from a faculty position at Carnegie Mellon’s Robotics Institute, where he’d been working on a project with Red Whittaker—a robot called Groundhog that was designed to map Pennsylvania’s abandoned coal mines. His new job was in Palo Alto, California, leading the Stanford Artificial Intelligence Laboratory, a once-respected research facility established by AI pioneer John McCarthy in 1963, which had been dormant since it had been rolled into the greater computer science faculty in 1980. To reincarnate the facility, Thrun brought nine Carnegie Mellon academics with him. Having left behind all his projects at his old school, Thrun was looking for a quick way to reestablish the AI lab’s reputation.
Thrun had attended the first Grand Challenge as a spectator, and was intrigued by the prospect of entering the second, as the rebooted Stanford AI lab’s first major feat. So Thrun asked one of his fellow CMU transplants, who had also attended the first challenge, to conduct a presentation to the rest of the group.
The presenter was Mike Montemerlo, a soft-spoken engineer who had a reputation as a software whiz known for his ability to program robots to conduct the simultaneous localization and mapping that had so bedeviled Sandstorm in the first race. Montemerlo’s father, Melvin Montemerlo, was a program executive at NASA and had worked СКАЧАТЬ