October 30, 2007
Days 5-6: The Field Narrows
Hello, friends of DEXTER! I apologize for not updating yesterday, but I assure you our time has not been wasted! The field has narrowed by six teams as of this writing, but DEXTER and Team Case are still in the race!
On Monday, we replaced DEXTER's batteries. This has greatly improved DEXTER's idling and electrical performance. We also re-ran course A on Monday. We had a problem where the left LIDAR (laser scanner) was tilted too far down and was seeing the road to the front and left of the vehicle as an obstacle. This caused DEXTER to err on the side of caution and not take his turn at the intersections at track A. We've since fixed this issue, and hopefully we'll get another shot at "A."
Another issue that had been giving us trouble is that our vision computer was running on the same 300W 24V DC/DC converter as the LIDAR units, so that power bus was right on the edge of its budget. This situation was exacerbated by our old batteries. So, we decided to mount an additional Vicor 500W 24V DC/DC converter to the vehicle's 48V bus. Unfortunately, during the upgrade, the 24V line came into contact with hot 48V and we lost three LIDAR units - the side two and the rear one. I learned of this around 1AM, so I woke back up and got to work on repairing the system through the night. This involved re-wiring the power connector blocks (which were charred), moving some of our existing and spare LIDARs (the front-left and front-vertical units were moved to left and right, and a spare was mounted at the rear), and updating our sensor placement configuration files to take all this into account.
This morning, the Georgia Tech Sting Racing Team, who has already been eliminated from the competition, graciously lent us two of their LIDAR units. Using these, we were able to re-populate all of our LIDAR mounting locations. CALTECH also let us borrow one of their spare LIDARs. We've ordered new units, but they won't be here until after the NQE is over. So, we are extremely grateful to GT and CAL, who are a class act for helping us out!
As I'm typing, DEXTER is getting ready for his second run of Course B, which is the most similar track to the final competition. I'll post an update later today with DEXTER's results! If you haven't seen it yet, you can also watch DEXTER's first track A run online. Go Team Case!
Posted by: Bradley Farnsworth October 30, 2007 12:43 PM | Category:
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Posted by: bdf (Bradley Farnsworth) October 30, 2007 12:43 PM | Comments (7)