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Unread 21-04-2012, 00:33
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AKA: James Killian
FRC #3481 (Bronc Botz)
Team Role: Engineer
 
Join Date: May 2011
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Location: San Antonio, Texas
Posts: 298
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Re: High Speed Encoder Problem

Quote:
Originally Posted by Mr. Rogers View Post
Hey, we have a 128 click encoder for our shooter speed. Our java programmers managed to get an encoder velocity, but it updates constantly and is all over the place, it ranges +/- 1000 clicks per second when we run a constant speed on the shooter motors, any way to clean up the "noise," if that's the problem. Thanks.

We ran into a stroke of luck tonight to find the ROOT cause of a similar problem. This can be best explained like so:

Our shooter was not quite aligned for some time, and as it hit those higher speeds the vibrations of the casing were so intense that it cracked the casing around the encoder... the little wheel inside the encoder started to roll around inside its own casing as such where during certain intervals it briefly lost connection and did not deliver the pulse counts. When I say brief, I mean about 3 iterations per 10 where each iteration ran about 10-11ms. We fixed the damage the best we could with electrical tape, and ensured the wheel inside kept constant contact.

It was interesting how we found this problem by sheer luck... as we just happened to press against it while I was reading the dump, and saw the numbers looking much better during the period it was touched.

Hope this helps.