Quote:
Originally Posted by Michael Hill
While having brownout at such a high voltage sucks, it should just be treated as another design constraint. It's basically a built-in current limiter, something that exists in A LOT of real devices. You go over [X] current, you blow your power budget...maybe it's just the Aerospace Engineer in me. Successful teams will find ways of managing their power budget (disengage a CIM when it's not needed, use thicker power wire, run the compressor at strategic times, etc.). I'm not saying I would like a lower brownout voltage, but I have a hard time thinking there's anything that will be done on the RoboRio to fix the issue. So for now, we just have to treat it as another constraint.
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If this were the "real world," I would say, sure, one more constraint, add it to the list. BUT it isn't. This is a system who's job is to control a robot that plays a FIRST FRC game. FIRST was painted into a corner with the cRIO. They had insane time pressures and the had to pretty much take what they could get.
But the RoboRIO? It was designed SPECIFICALLY for FIRST FRC. It was a huge oversight to have anything important loose power, ever.
Another problem is that FIRST's system is SO COMPLEX that it is basically impossible for teams to duplicate what happens out on the field in their pit or even on the practice field.
I am not saying that it would have made that much of a difference but this whole brown out thing cost us in St. Louis. Our first competition match on Carson, something disabled us during auton, then re-enabled us. Shame on us but our code just restarted our auton and ran it again - which broke the robot. Here is the thing. Half of our Qualifying Matches were gone before we got a reasonable answer as to what the problem was and had a work around. It seems to be something related to our robot pulling the voltage below 7V for a small fraction of a second at one point in our auton.
Again, so, yes, shame on us for not realizing that we were close to the edge for 4 prior tournaments where we never saw this problem. But also shame on FIRST for having an unnecessary edge for us to fall off to begin with and for not providing a person with the time and the knowledge to diagnose tricky problems such as ours (had it not been for Mike Copioli and one of his minions from CTRE, we'd still be in the dark about it).
So, that is my team's experience. If you're not on our team, it is easy to say, "Who cares?" Except, I am sure that there were many other teams that ran into problems as well.
Bottom line, I think this is the bad fruit that grew from a bad seed. FIRST should have made this a non-issue with the new controller.
Dr. Joe J.