Quote:
Originally Posted by Aren_Hill
we had 4 on the 2008 bot, not a single issue, and 1 on the 2007bot no issue. we've begun using them instead of pots because of the reliability we've had.
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We had a particularly dry (as in, not humid) practice area for the last few years which I think accentuated the problem. With the increase in static charge build-up this year, it may become more of an issue. Anyway, if you're happy with them then great - I'm just putting out a warning that we had a lot of trouble with them.
What we had happen all the time last year is that we'd be driving around, then the robot would get close to a metal part of our field border, we'd see and hear the static discharge (large blue spark was visible), then our encoders would go haywire, sending semi-random but increasing values even though our crab wheels were not turning. This, in turn, caused our feedback loop to incorrectly move the wheels to correct, which would end up spinning them too far and ripping wires out etc. We added a fail-safe to prevent them from spinning for more than a second or two to address the symptoms but never were able to fix the root problem. Most often, power-cycling the encoders would fix the issue, but every now and then they'd be damaged permanently.