Results tagged “DARPA Grand Challenge” from kwc blog

correction: this occurred in the 2005 Grand Challenge, not the 2007 Urban Challenge.

There's a short article from Princeton team member Brian Cattle on how a memory leak caused their Urban Grand Challenge entry to fail. In their testing, the system would fail after 40 minutes. Not knowing what to do, they set the code to restart itself every 40 minutes -- sounds good, right? During the actual event their car failed after 28 minutes. Doh!

The article is essentially a marketing piece for the ANTS Profiler, while writeups over at robots.net and Slashdot are trying to blame Princeton's choice of C# and Microsoft Robotics Studio. I'm happy to use profilers and bash Microsoft, but in this case their bug was programming mistakes 101: they subscribed objects to events and neglected to add the one line of code to remove subscriptions when those objects were deleted.

In Princeton's case the objects were the obstacles that the car was seeing. In their testing, it would take 40 minutes to see enough obstacles to cause their problem. The DARPA course had more obstacles and caused a failure in 28 minutes.

DARPA Grand Challenge on PBS

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NOVA aired a special called The Great Robot Race covering the 2005 DARPA Grand Challenge. If you missed it, PBS has been kind enough to post the entire program online -- sweet.

NOVA also has one of my favorite video podcasts. Recently, they've been airing amusing mini-programs from the DARPA Grand Challenge. Great stuff for people who short attention spans like me that want our stories in 2-3 minute chunks.

Previously: * Sebastian Thrun's talk on Winning the DARPA Grand Challenge * DARPA Grand Challenge link roundup

Talk: Winning the DARPA Grand Challenge

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I went to go see Sebastian Thrun speak at Stanford about his team's winning effort in the DARPA Grand Challenge. Thrun described the contest as how to stay on the road for a very long time. It was not a general path-finding problem: DARPA gives you the route with a corridor you have to follow, as well as speed limits you have to observe for various parts of the course. Of course, DARPA didn't give perfect data. He showed a video generated from the data of Stanley driving through the most dangerous part of the course: the switchbacks of Beer Bottle Pass with a cliff on one side. DARPA's corridor was overlaid on top of Stanley's sensor data and it was easy to see that much of DARPA's corridor was actually over the cliff.

During training many traffic cones were "frequent victims of computer glitches," but Team Stanley was called "Team Boring" by the cleanup crew for their lack of incidents. The actual challenge was described as getting the data at 4AM, getting Stanley to the starting line at 6AM, and then sitting around drinking beer for several hours. The big moment came when Stanley passed CMU's Highlander as the CMU and Stanford teams listened to race radio. Thrun narrated the exciting finish for us: "[The head of DARPA] is waving his flag as if the car could see it."

Thrun said that they won mostly through luck given how close four of the teams finished. The speed limits set by DARPA for the various parts of the course were too conservative, so the cars were running below their full potential. DARPA also decided to make the course fairly easy. Asked if CMU would have won had they not had engine problems, Thrun answered, "In all likelihood, yes." Also, Team ENSCO had a faster average course time but flatted on "something really big CMU left behind" (the CMU part may have been a joke). Thrun felt that Stanford had better software than CMU and on a tougher course Stanford would have the advantage.

In the future, Thrun wants to try driving 65mph on 280, parking in a garage, convoy driving, and driving assist. Part of his motivation is to reduce traffic deaths, which a driving assist system could help prevent. He also feels that a fully automated system would change society by allowing you to use your commute time productively -- you could even drive to your destination, get out, and then send your car to go park in a parking garage farther away. These are still looking far ahead. In response to someone asking what it would take to drive at human-controlled speeds, Thrun related it to asking the Wright brothers, "If you want to fly over the Atlantic, what's missing?"

DARPA Grand Challenge

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This year's DARPA Grand Challenge looks like it was pretty awesome. People from work have been sending links to their photos (see below) and it's amazing to me to think that in the year since the inaugural competition there are already five autonomous robotic vehicles that completed the 130 mile course and the $2M prize has been claimed. I'm also happy to see that students from my high school were on a team (ENSCO) that made it two-thirds of the way through the course and finished sixth (highest of the non-finishers).

Yesterday I got to talk with someone who got to drive a chase car in last year's Grand Challenge. The vehicle he was following had been programmed to avoid obstacles and had a general plan for getting to the destination, but it didn't have much else. What happens when you only teach a vehicle to avoid obstacles? It finds obstacles and then avoids them, so instead of driving along the road, it would find two bushes along the side of the road and drive between them.