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Unread 17-03-2012, 19:08
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SteveGPage SteveGPage is offline
Mentor - Scouting and Strategy
AKA: Steve
FRC #0836 (RoboBees)
Team Role: Mentor
 
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Re: Intermittent connection on field only

Joe,

This sounds very similar to what was happening to us at Chesapeake. We, too, thought it had to be the FMS, since we were only having the issues when we connected to the field. The FTA said, that in his experience, the type of connection issues we were having were usually due to hardware issues. We replaced several wires, swapped out our cameras, removed the cameras, etc... All approaches I see above. We re-checked every connection, taped down everything that might move, did a very thourough shock and vibe set of tests on the bot in the pits, and then, at least, everything seemed to work in our first quarterfinal, and thought we had found the issue. The next match, we were playing blind again, our cameras had dropped the frames, and the lag times between the camera and the dashboard were killing us. we asked the FTA if the logs showed any connection issues, and he said no. He then said, "You do have, however, a lot of latency showing up. A lot more than I would expect."

We decided to bring the cameras home and run tests with our practice bot to see if we could re-create the issues, but were generally unable to do so. A post here on CD, regarding the 3-13 update had a post from a member of the Killer Bees (33) talking about issues he had found in some of the LabView code, and he posted a sample code he had written that had helped with some of the latency issues they were having.
http://www.chiefdelphi.com/forums/sh...=104580&page=2
It sounded familiar to our problems, so I forwarded the info to our programmers. Other than some of the basic code, our team had written a lot of the code ourselves. When they reviewed the info in this post, they found some of the same issues mentioned. They have been optimizing the code as described, and finding that the code is now a lot more efficient. We are continuing to run tests to see if there are other issues, but are hopeful that when we get to DC, we will not see a repeat of the problems we had in Chesapeake.
In previous years we had build rather "simple" machines, with very little reliance in sensors and complex code, this year, we have two cameras, complex image processing, a complex set of code that keeps track of the state of each ball in the system, etc... I'm wondering if this year's general increase in the complexity of the bots teams are building is bring some of these code issues to light? If you all find anything else that is causing these problems, I would love to hear about it. Thanks!

Steve
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