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Author Topic: Boost PID tuning  (Read 59127 times)
Rick
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« Reply #30 on: August 04, 2012, 02:02:13 PM »

Not quite.

Don't forget your set point isn't always going to be reached at 3600.  What if you floor the throttle at 4k?

Rick
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Bische
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« Reply #31 on: August 04, 2012, 11:34:33 PM »

Not quite.

Don't forget your set point isn't always going to be reached at 3600.  What if you floor the throttle at 4k?

Rick

Yes, I realized this shortly after my post. Setpoint is also reached sooner in higher gears.. I also read up on PID controllers and their tuning and found out I had some terms wrong due to translation.

I thought about this and came to conclusion that the integer should probably be around 80% and the proportional the remaining 20% up to meet setpoint?

Does anyone have a log with stock turbos/PID maps?
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silentbob
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« Reply #32 on: August 04, 2012, 11:54:45 PM »

Bosch boost control is shit because there is no proper way of precontrol for the valve.
What you can do for better boost response is use the strategy that is implemented in the RS4 with using LDDIMNN as precontrol. But use with caution because this tends to overshoot.
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Bische
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« Reply #33 on: August 05, 2012, 01:05:37 AM »

Thanks for the tip!

I noticed my P, I and D maps are all KF's, this should allow for more flexibility:
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nyet
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« Reply #34 on: August 05, 2012, 01:29:50 AM »

Integer != Integral
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Bische
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« Reply #35 on: August 05, 2012, 03:15:00 AM »

Integer != Integral

Thanks, corrected Smiley

I have a question: How is the pressure axis used in the P, I and D maps?

Example:

error/lde is 900hpa, my axis looks like this:

100  25
200  26
400  27
700  28

Does it use the 700 axis to multiply with?

(900/700=1,285714285714286) x 28 ?

Or does still multiply by each 100hpa, and use the value of 28 in my 700 axis?

(900/100) x 28 ?
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nyet
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« Reply #36 on: August 05, 2012, 10:43:20 AM »

some are lde, some are ld.. you'll have to consult the FR to know which.
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silentbob
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« Reply #37 on: August 05, 2012, 11:04:40 AM »

............................
Or does still multiply by each 100hpa, and use the value of 28 in my 700 axis?

(900/100) x 28 ?

This is correct
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Bische
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« Reply #38 on: August 05, 2012, 11:30:49 AM »

some are lde, some are ld.. you'll have to consult the FR to know which.

Yeah I know the axes is lde, but I was riddled how/if it was used in the math.

This is correct

Thanks for confirming  Smiley
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nyet
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« Reply #39 on: August 05, 2012, 11:44:10 AM »

Sorry, I misunderstood your question..

And even worse, I don't understand the answer either Smiley

Can you or silentbob go through it for me?

Thanks, I appreciate it.
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nyet
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« Reply #40 on: August 05, 2012, 11:49:36 AM »

Ok i think i understand what your question is.

The example you gave is lde=900hpa

The row you are looking at is

700 28 (last row, since 700<900)

The result is 28 (which is in % per 100hpa)

Which means the actual coefficient is 900/100 * 28 (28 per 100 hpa)

What threw me was "Or does still multiply by each 100hpa", which i incorrectly read as "multiply each by 100hpa", instead of "multiply by 28 per 100hpa"
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matchew
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« Reply #41 on: August 05, 2012, 12:09:49 PM »

Any value above 700 will use 28
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nyet
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« Reply #42 on: August 05, 2012, 02:11:17 PM »

Which means the actual coefficient is 900/100 * 28 (28 per 100 hpa)

Actually, this isn't always true.

The usage of the output is only lde on the P part.

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Bische
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« Reply #43 on: August 07, 2012, 11:59:18 AM »

Can someone explain this to me:
Quote
P component (LDRQ0DY (or LDRQ0S) - KFLDRQ2 (or 0)) = * lde ldptv

Why is the D component subtracted from the P component? Or I guess my question really is, why isnt the P% set lower from the beginning with the D% = 0, instead of setting the P% to 25 then subtract 18 from the D%?
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nyet
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« Reply #44 on: August 07, 2012, 12:10:07 PM »

The answer to your question is more of a PID/math theory question .. you'll have to look more at the various PID "forms".

The basic form  "Kp(P) + Ki(I) + Kd(D)" isn't the only form.
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Please do not ask me for tunes. I'm here to help people make their own.

Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your ex
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