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#1
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Re: paper: Shooter Wheel Speed Control
We've settled on PID because we simply can't get the bang-bang method to give us better results. The real issue that I think I've hit is mechanical - we're at the limits of what our system can provide. No matter how we play with gains, filtering, etc, we're struggling to get the shooter more than +/- 40 to 60 rpm (actual RPM, not filtered much at all other than to remove big spikes that are obvious errors).
Filtering the speed before our 'enable shooting' vi really doesn't help shooter run any more consistently - it just makes it easier for us to check the limits. I did put a 4 sample moving average in to filter the pid input. That helped with some of the oscillation. We also turned down our proportional gain (we wrote a velocity PID, we're not using the position PID) to help some of the oscillation. The shooter still spins up in around 2 seconds, but that helped the oscillation as well. I had hoped to manage a major improvement before nationals. We've improved our velocity control probably 50%, but other folks are reporting numbers that are still close to 100% better than ours. That means that in real time ball shooting, we're seeing something like +/- 1 foot in height when hitting the backboard. |
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#2
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Re: paper: Shooter Wheel Speed Control
Hey, I didn't read the whole thread but just wanted to mention that this will not work with a Spike. I haven't tested, but a while ago I read into how the Spike works and it cannot coast, it either powers the motor or breaks.
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#3
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Re: paper: Shooter Wheel Speed Control
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Connect one lead of the motor to the PDB(-), and run the other lead through one relay in the Spike to the PDB(+). anyone: Is this FRC legal? See ensuing posts. Doh! Last edited by Ether : 22-04-2012 at 18:11. |
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#4
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Re: paper: Shooter Wheel Speed Control
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I could of course be very wrong ![]() |
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#5
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Re: paper: Shooter Wheel Speed Control
No, you're right.
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#6
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Re: paper: Shooter Wheel Speed Control
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It wouldn't be FRC legal. Also, because a Spike is a mechanical relay, don't they have a limit as to how quickly they can switch to ON/OFF? |
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#7
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Re: paper: Shooter Wheel Speed Control
When you make such a statement, you should reference the rule you have in mind.
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#8
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Re: paper: Shooter Wheel Speed Control
I'm not saying you're wrong, but what is your source for this information?
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#9
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Re: paper: Shooter Wheel Speed Control
I think the rule violation would either be:
Quote:
Quote:
I remember hearing/reading about it being one, and it seems to behave like any electro-mechanical relay I've used also. (Mainly, the clicking sound when it switches) |
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#10
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Re: paper: Shooter Wheel Speed Control
Quote:
Quote:
Last edited by Ether : 22-04-2012 at 18:36. |
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#11
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Re: paper: Shooter Wheel Speed Control
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