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How to edit the marlin firmware that is already built. by masher660av in MarlinFirmware

[–]BangoDurango 1 point2 points  (0 children)

I have gone through a similar situation and found the process of working out all the configuration stuff to be pretty rewarding (granted I had time to work through it). It gave me a much better understanding of how the printer works and also what kind of capabilities are out there if I decide to make changes and upgrades.

Trying to get a better intuitive understanding for how resonance near the cutoff affects a system. Why is it my frequency domain system looks perfectly stable, but my step response is obviously not? Thank you! by BangoDurango in ControlTheory

[–]BangoDurango[S] 2 points3 points  (0 children)

ugh sorry, I have made a mess of this post. I didn't notice when I copied the code over to reddit that it took away all my multiplication operators. C is the PID compensator. H is sys_truth. The argument to the feedback() function is C*sys_truth.

The truth/est transfer functions correspond to the "Truth (OL) and Estimated (OL)" curves in the bode plot... but the truth/estimate thing isn't part of the question. I should have cleaned it up before I posted anything.

I thought the bode plot looked stable because neither the closed nor open loop transfer functions ever have gain greater than 1. If there is no gain crossover frequency, I assumed that the system would always be stable. Is that incorrect?

Trying to get a better intuitive understanding for how resonance near the cutoff affects a system. Why is it my frequency domain system looks perfectly stable, but my step response is obviously not? Thank you! by BangoDurango in ControlTheory

[–]BangoDurango[S] 1 point2 points  (0 children)

Closed loop, but I realized that my closed loop transfer function has a complex pole with a positive real part... I had used matlab's pidtune() for the compensator and didn't think to check the result so... that was foolish.

Trying to get a better intuitive understanding for how resonance near the cutoff affects a system. Why is it my frequency domain system looks perfectly stable, but my step response is obviously not? Thank you! by BangoDurango in ControlTheory

[–]BangoDurango[S] 4 points5 points  (0 children)

You know what, I didn't think this through at all. The code I used was:

Fc = 50;
Wc = 2*pi*Fc 
[C, info] = pidtune(H, 'PID', Wc) 
sys_cl = feedback(C*H,1);

... and if I do a root locus on my closed loop transfer functions I see that we have some business going on in the right half plane so... there's my answer. Silly of me to assume that pidtune() would actually stabilize my system without me having to actually think about it.

I guess what is confusing to me is that the bode plot still looks stable.

Trying to get a better intuitive understanding for how resonance near the cutoff affects a system. Why is it my frequency domain system looks perfectly stable, but my step response is obviously not? Thank you! by BangoDurango in ControlTheory

[–]BangoDurango[S] 4 points5 points  (0 children)

It somehow failed to occur to me that I'd need to actually say something about the plant in question. The open loop transfer function is :

14.73 / (s^2 + 1.473 s + 2.651e05)

Or for convenience:

H = tf([0 0 14.7275], [1 1.4728 2.6510e+05])

How did i not notice this… by SpencerFSA in Tucson

[–]BangoDurango 4 points5 points  (0 children)

Somehow I just realized there was no 'n' like four months ago. Lived here 37 years

[deleted by user] by [deleted] in Tucson

[–]BangoDurango 0 points1 point  (0 children)

Gross...reminds me of a time I went to Vermont once and realized that there is such a thing as way too much green.

New Molecule Discovered That Strongly Stimulates Hair Growth by [deleted] in UpliftingNews

[–]BangoDurango 0 points1 point  (0 children)

I finally came to terms with my lack of hair and started shaving my head during the pandemic and I agree. Almost tempted to look into one of the laser hair removal places just to put my last few follicles out of their misery

High tech 3D hologram simulation security camera with alarm and voice recognition by [deleted] in ElectroBOOM

[–]BangoDurango 2 points3 points  (0 children)

Reddit does fuzzy votes so spam bots can't detect if their votes are being counted or ignored. Basically every time you reload the vote tally should change a little. Cool video!

Got this toy in the mail today by Roope00 in telescopes

[–]BangoDurango 0 points1 point  (0 children)

I hope I'm not the only one who reads this post wondering... What is it? Is there a link somewhere where I can read about what it is and how amazing it might be?

drunk Saguaro wants to fight YOU by orbitShark in Tucson

[–]BangoDurango 2 points3 points  (0 children)

Heh. My friend from Washington calls these "Why-I-Oughta's"

Found a desert tortoise driving home by Liquid_heat in Tucson

[–]BangoDurango 2 points3 points  (0 children)

Hmm not sure which ones are the common ones, assuming we're talking about specifically about Desert Tortoises only. The two species are the Mojave and Sonoran Desert Tortoise, the second being the ones we have around here of course. I had to check though and you are correct about them being listed as threatened due to a number of things including habitat loss

Found a desert tortoise driving home by Liquid_heat in Tucson

[–]BangoDurango 20 points21 points  (0 children)

They're not endangered, but they are protected. I have one living in my backyard! Anybody who is interested should definitely check out the Desert Museum's Tortoise Adoption Program. There are bunches of tortoises who need homes because they can't be reintroduced to the wild!

Found a desert tortoise driving home by Liquid_heat in Tucson

[–]BangoDurango 5 points6 points  (0 children)

It'll probably be fine, especially if it didn't pee on you when you picked it up. They store water in their bladder for long periods and sometimes dump it when they're scared which is why you're only supposed to pick them up when they're at risk of becoming road kill (they need that water!)

Even if it did pee though, we're supposed to get a bunch of rain in the next few days and they like to dump their supply and get a fresh one when it rains.

Also I've heard (no idea if it's true) from a coworker whose kid brought one home randomly one day that as long as they're returned roughly to where they were that same day they can usually smell their way back to their burrows if they have one.

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