Quote:
Originally Posted by Bryce2471
Great data. Thanks for that contribution. I have a couple questions:
How long did you wait between shots?
How much was the steady state error effected when you changed the set point.
How much time, or how many iterations did you spend tuning the Kf value? How about Kp?
Thanks again.
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1) We didn't time this precisely, but it was on the order of 10 seconds.
2) We haven't rigorously tested this yet, will report back once we have data
3) We tested our flywheel speed at max voltage, and then simply naively set Kf to (max output)/(max speed). We did not test across multiple battery voltages or setpoints - if anyone has suggestions for a good systematic way to do this, it'd be appreciated.
4) We started Kp pretty small and then doubled it until we started to see oscillations, at which point we set it to halfway between that and the previous value. There were a couple more iterations after that, I think, but I don't recall exactly how many.
All in all, it was a pretty "rough" tuning procedure - we were mostly interested in getting it working, with the understanding that we can fine-tune it later.
Quote:
Originally Posted by Jared Russell
We didn't use integral gain, but we did use some derivative gain to lessen the initial overshoot, and a 36V/s rate limit to smooth things out a bit:
https://github.com/Team254/FRC-2016-...ants.java#L152
(Talons were in coast mode as well)
We allowed firing whenever our flywheel was within 100rpm (1.67rps) of our setpoint because we found it made no practical difference to our shot trajectory. In practice, most shots we took were within 20rpm of our setpoint. If you are within .1rps (6rpm) steady-state, I'd say you're already in good shape. |
Thanks a bunch for all of your input - it's greatly appreciated. I'll add these to the list of things to try.
Hopefully we'll find some time to sit down and really play with different tuning schemes, and record the data.