Day 4 – Successful run in Area C

October 30, 2007 (1200 hrs), VICTORVILLE, CA. If you’ve been staying up biting nails, rest easy. CajunBot had a very successful run in Area C. This is the same area where we started our Day 1. Today’s performance was not picture perfect, but close enough.CajunBot completed the mission, which involved making eight laps around a loop. The loop had two four way stops. At each four way stop, CajunBot was to come across other vehicles. She was expected to follow the precedence rules for stop signs. Vehicles that arrive before you at the intersection have the right of way, before you.

Unlike our first run, CajunBot did perfect this time, in all except one intersection. The good news is that she did not go out of precedence. Which means none of the drivers had to hit pedal to the metal to escape her kiss, as they had to for the first run. The only exception was when she was a bit too gracious, and would not take her turn. The situation was a bit complex. Three vehicles were already at the intersection before she arrived. One vehicle left, and another (a fourth) vehicle drove up and stopped at the same place. The other two vehicles left. Now CajunBot should have moved. But she did not. Finally, the fourth vehicle moved, at which point CajunBot moved on.

For all practical purposes this appears to be a minor flaw, say in comparison to chasing a driver out his wits.

Talking about drivers, I chatted up with one, to learn how he could put himself in front of these reckless bots. He, and other drivers in Area C, are moving stunt men. They get thrill in making close calls. But I thought movie stunts are choreographed, so the risks are a lot controlled. But in these tests, there is no way to guess when a bot may go beserk. I sure do not want to be in their position. And I am sure they think they same about me.

Other than the intersections, there was one more test in this area. The bot had to detect that a road was obstructed, turn around, and find another way to get to the checkpoint. The checkpoint was on the other side of the obstruction, so she had to get to the other side, make another turn and come back.

CajunBot was perfect in replanning.

In essence we had overcome two of three issues that stumped us in the first go. We had fixed our algorithm to use sensor data to understand the world. We had fixed our replanning algorithm.

The one issue that is still not fixed is our ability to deal with imperfect GPS data. In the last test, the bot was driving on the curb but, based on GPS data, thought was on the lane. We did diagnose the reason for the GPS ‘drift’. Before the bot was launched, she is brought in a staging area. One end of the staging area has large trees with thick canopy. This was blocking a significant part of the sky, thus limiting the satellites that were in direct view.

We addressed the GPS drift at least for this run. Joshua was monitoring the GPS data in the staging area. When we started receiving error messages, we asked DARPA officials to move us to a different location. This led to a lot of radio chatter, getting approval from the higher chain of command. The request was granted. So when the bot was finally launched, she had already recovered from the temporary loss of GPS.

Several of you have sent compliments on the video from Area A. The compliments go to Scott. He is a videographer, director, and editor all rolled into one. He is working on a video from today’s run. By the evening we should have an upload.

Tomorrow we have two runs. In Area A at 0730 hrs and in Area B at 1220hrs.

Pre-run sunrise (by Adrian):

Approaching front intersection (by Adrian):

– Arun Lakhotia

5 Responses to “Day 4 – Successful run in Area C”

  1. I am glad to hear about the run.

  2. Even with the hiccup at that one intersection, sounds to me like she’s a better driver than most here in Lafayette. Keep up the great work!!

  3. It’s quite a testament to your team that it can move and adapt so quickly. It’s your Cajun Secret Sauce and its irreplaceable. Looking forward to both tests tomorrow.

  4. Take the cell phone away and all will be fine…we are so proud of you, year after year…the best! Geaux Cajuns

  5. Lee Johnson says:

    Very Inter resting applications, moon, mars, maybe, earth moving equipment, if you apply it to heavy machinery e-mail me maybe I can help. Green H1 @ Adalanto Gas station Thanx for the hat and Tshirt. I have 30+ years in dirt work. your ideas should work well on a scraper, dozer or excavator. Leland Johnson Gardnerville NV.

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