Autonomy. Lawrence Burns

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СКАЧАТЬ computer file at 4:30 A.M. The file would feature a series of about 2,500 GPS waypoints, which everyone referred to as “breadcrumbs,” spaced about a hundred yards away from one another, tracing out the course in a dot-to-dot fashion. The dozen members of Red Team’s planning unit would leap into action. One would feed the file into a software program that used the Mojave map’s cost estimates to build a more precise route, with many times more breadcrumbs than DARPA’s route network definition file (RNDF).

      But Urmson, Whittaker and their team didn’t trust the route calculated by the planning software. It had been known to send Sandstorm on journeys that went over ridges, into ditches or through wire fences. So a team of editors would divide up the course into sections and then, using computers, virtually go over every yard of the computer-calculated race path to make sure the software hadn’t made any mistakes. Once the human editors were done correcting the course, they’d reassemble it into a single route and upload it to Sandstorm, to execute on the race course.

      Still, by January 2004, just two months before race date, Sandstorm had not yet gone fifty miles on its own. One thing causing Whittaker and Urmson anxiety was the disconnect between where they were testing Sandstorm and the race course. They were testing the robot on the frigid shores of Pittsburgh’s Monongahela River. The race would be held in the Mojave Desert. Would the change in environment pose a problem to Sandstorm?

      In February, Whittaker arranged for some of the team’s key members, including Urmson, Peterson and Spiker, to accompany Sandstorm to the Mojave Desert to refine the robot’s capabilities. (Sandstorm actually made the trip in a fifty-two-foot enclosed semi-trailer.) The final part of preparations would happen at the Nevada Automotive Test Center, an enormous swathe of desert where companies from all parts of the automotive sector, from tire manufacturers to transmission firms, tested their products in the harshest desert terrain available.

      In Nevada, Urmson’s team worked exclusively on Sandstorm. Write code, take Sandstorm out to test the code, watch for mistakes, take note of the mistakes, write code. They repeated the cycle without regard to clocks or arbitrary separations of day and night. Two, three days at a time they worked without sleeping, fueled by Mountain Dew, Red Bull and junk food, and then, when they were too exhausted to manage to keep themselves vertical, they slept. Sometimes in an RV they’d rented, although the trailer didn’t have enough beds for all of them; others slept on the floor of the test center’s mechanics shop on folding lawn chairs, or in the reclined seats of the SUVs they rented to tail Sandstorm.

      Working nonstop, through night, through day, the way they did presented some difficulties. One evening, past midnight, Sandstorm ran into a fence post, wrecking the front bumper, which was necessary to support cameras and radar sensors. The test center’s mechanics building was locked up, of course, but in the spirit of asking for forgiveness being easier than requesting advance permission, Spiker and one of the students scaled the fence and broke into the building, where they welded together an entirely new bumper with thick steel pipe. The thing ended up weighing about two hundred pounds—making it more than able to support the sensing equipment the robot required. “You could probably have driven through a building and not hurt that thing,” Spiker recalls.

      One thing they didn’t do much of was bathe. The wastewater tank in their rented RV filled up, and by the time they got around to driving it to the nearest town to empty it, the vibrations from the washboard dirt road into town splashed sewage all over the RV’s interior. Cleaning the mess was so traumatizing that the team outlawed use of the RV’s bathroom. While there were bathrooms available in the mechanics shop, no other showers were available, so the guys went without washing for about six weeks. Then, in mid-February, one of their computer sponsors, Intel, invited the Nevada members of Red Team to San Francisco, where the computer chip manufacturer wanted to show off Sandstorm at the Intel Developer Forum.

      By that time, Sandstorm had managed a speed of 49 mph and an autonomous run of a hundred miles. The guys were excited about the progress they’d made. But the robot still had its mechanical idiosyncrasies. It was apt to see obstacles that weren’t there, or miss obstacles that were, or even misinterpret pre-programmed commands. What if something like that happened while Sandstorm was onstage at the conference?

      The following morning, an audience of hundreds watched the autonomous vehicle creep out onto the stage, apparently thanks to the benefit of high-tech sensors, engineering and computers powered by “Intel inside.” The crowd cheered in response. The applause felt good to the Red Team members present. Here they were at a Silicon Valley event being treated like celebrities. The recognition validated their sacrifices and the worth of the project. It also made the team thankful that no one realized that during the onstage demonstration, a Red Team member had hidden in the space under Sandstorm’s steering wheel, prepared on a moment’s notice to slam his hand on the brake pedal if the massive robot threatened to roll off the stage into the crowd.

      On Friday, March 5, 2004—eight days before the race and just three days to go before the qualifying events—Chris Urmson rose early in the morning, put on his usual uniform of a mud-spattered baseball cap, fleece sweater and worn jeans, laced up his running shoes and decided that today would be the day to stage Sandstorm’s culminating test challenge.

      Urmson, Peterson, Spiker and the rest of the Nevada squad tested Sandstorm in the worst conditions they could imagine—frequently, along sections of the trail the old Pony Express had followed more than a hundred years earlier. “Red is really gung-ho about testing hard,” explains Peterson. DARPA had said its route would be about 150 miles. The longest run Sandstorm had made was a hundred miles. But with the race a little more than a week away, everyone on the team was hoping for a longer run to boost their confidence.

      The goal was just like the race: 150 miles in ten hours. The route amounted to a flat oval, about two miles around. While they prepared Sandstorm, Urmson and Peterson tinkered with a new part of the software: a component of the speed-setting module designed to slow down the robot when it approached a curve. The new code was designed to allow Sandstorm to drive more quickly on straightaways.

      The code worked wonderfully. During a few warm-up laps, Sandstorm managed to get up to 49 mph along the straightaways and then the new algorithm slowed it down as the robot headed into the curves. In fact, as Urmson and Peterson watched the robot, they wondered whether it slowed Sandstorm too much. An adjustment to the algorithm during a refueling break seemed to improve things. On the first lap they watched as Sandstorm cruised into a curve, slowed a little bit and then accelerated through the curve’s exit. At the end of the second lap, Sandstorm was heading fast into what Urmson would later describe in his field test report as a “soft S-curve” to the left. The right-side tires drifted off the road into deep sand, and when Sandstorm tried to correct things, to get back on the track’s packed-down dirt, it steered too hard to the left. The right-side tires bit into the soft sand. The left-side tires came up off the road. Behind, in the chase car, Urmson watched, horrified, as Sandstorm tipped up and over, and came to rest upside down—right on top of the e-box and the gimbal housing all the vehicle’s most sensitive equipment.

      The robot had been designed to insulate the box’s components from being damaged in all sorts of accidents. Front-end collisions, rear-end collisions—pretty much any collision that happened on the ground plane, Sandstorm would be able to withstand just fine. But the robot had one fatal weakness: a rollover. Because Humvees sat comparatively low and flat, their geometry made rollover accidents almost impossible.

      Unless you were testing a robot Humvee in the Mojave Desert, apparently.

      A History Channel crew had come out to film the test run. They rushed out onto the track with their cameras and shoved one into Urmson’s face, asking him to list the damage. Urmson looked at the wrecked robot the team had spent the better part of a year engineering: at the crushed gimbal, the compacted GPS antennae, СКАЧАТЬ