[Dprglist] PID

[Ezra Christensen]

Patrick - do you have anyone on your team that is versed in ML? I'm
wondering if anyone has run an auto-tuning ML algo to come up with
coefficients, including possibly non-constant coefficients. The trial/error
approach seems tedious and prone to "close enough" calls from humans bored
of optimizing the three.

My FLL team built a calibrate sequence for i they would push before a run.
They found the motors and tires weren't consistent and the bot would start
driving better after X distance. Their hypotheses was that the total error
had to become sufficient to let the integral start doing it's part to
account for any mechanical drift of how the bot was feeling at that moment
(EV3s aren't super consistent, even with the same parts).


Ezra

On Thu, Sep 24, 2020 at 4:23 PM Patrick R. Michaud via DPRGlist <
dprglist at lists.dprg.org> wrote:

> While I've always been able to make good use of P-controllers, full PID
> tuning was a bit of a black box for me, even after reading lots of other
> resources (including the Wikipedia article).
>
> This past season our 7172 team needed much better control of their
> elevator -- P-control wasn't at all sufficient -- and the trick for us was
> to have the robot display the real-time contributions of P, I, and D to the
> result.  That really enabled the group to see how they could improve the I
> and D terms to get a more consistent result.
>
> I hope any videos/recordings of Tuesday's session are posted soon, I'd
> really like to see what was discussed.
>
> Pm
>
>
> On Thu, Sep 24, 2020 at 03:40:42PM -0500, David Anderson via DPRGlist
> wrote:
> > Howdy DPRG,
> >
> > As per our discussion at RBNO Tuesday evening on PID tuning, check out:
> >
> > https://en.wikipedia.org/wiki/PID_controller
> >
> > and particularly the cool animation of adjusting P,I,D values in the
> "Manual
> > tuning" section about half way down.
> >
> > There's also a useful "for dummies" page at:
> >
> > https://www.csimn.com/CSI_pages/PIDforDummies.html
> >
> > cheers
> >
> > dpa
> >
> >
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-- 
Ezra C Christensen
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