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Author Topic: PID contoller calibration from square one  (Read 73248 times)
julex
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« Reply #30 on: February 25, 2013, 09:54:20 PM »

If you are only calibrating up to 60%, then I would make KFLDRL linear from your newly adjusted 60% row to the 95%=95% row. But I'm just guessing. Experience/testing may prove different.

Thanks. Looks like audi did exactly that for 80 and 95 columns.
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airtite
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« Reply #31 on: February 26, 2013, 06:05:34 AM »

and then how are the runs done/logged? so lets say I lock wgdc at 10%, do I do a wot run in each gear and start a fresh vcds logging session for each run in each gear? how do I combine all the logs for that 10% wgdc together? sorry if these questions sound stupid but the last thing I want to do is do all this logging only to have to go and redo it all.
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s5fourdoor
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« Reply #32 on: February 26, 2013, 12:11:04 PM »

and then how are the runs done/logged? so lets say I lock wgdc at 10%, do I do a wot run in each gear and start a fresh vcds logging session for each run in each gear? how do I combine all the logs for that 10% wgdc together? sorry if these questions sound stupid but the last thing I want to do is do all this logging only to have to go and redo it all.

I switched my M-box to use RS4 axis.  Now my lowest functional column after 0% is 3% instead of 10% like on the stock M-box.
Here's what I'd do.  Set CWMDAPP = 8.  Set my KFLDRAPP to look like what you see in the image below.
Now.   Go out and find a nice stretch of road.  Get moving and get into third gear.
Do a few pulls from 1500 to 6500, or whatever your target power band is on your engine.
Go ahead and log your RPM and Boost Actual.
Take your logs and get your RPM and Boost Actual for each pull into a spreadsheet.

What you want to do is a linear interpolation.  So that you have a matrix with columns: [RPM_general BoostPull#1 BoostPull#2 BoostPull#3...]
Then you want to take the mean of your BoostPull#K columns, so you now have a mtrix:  [RPM_general BoostPullAvg].
Is that what you were confused about?  Get the data and upload it for me and I'll help with the mathematics for you if you need.
The spreadsheet gives you a great start on that tbh.
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airtite
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« Reply #33 on: February 26, 2013, 12:20:57 PM »

I switched my M-box to use RS4 axis.  Now my lowest functional column after 0% is 3% instead of 10% like on the stock M-box.
Here's what I'd do.  Set CWMDAPP = 8.  Set my KFLDRAPP to look like what you see in the image below.
Now.   Go out and find a nice stretch of road.  Get moving and get into third gear.
Do a few pulls from 1500 to 6500, or whatever your target power band is on your engine.
Go ahead and log your RPM and Boost Actual.
Take your logs and get your RPM and Boost Actual for each pull into a spreadsheet.

What you want to do is a linear interpolation.  So that you have a matrix with columns: [RPM_general BoostPull#1 BoostPull#2 BoostPull#3...]
Then you want to take the mean of your BoostPull#K columns, so you now have a mtrix:  [RPM_general BoostPullAvg].
Is that what you were confused about?  Get the data and upload it for me and I'll help with the mathematics for you if you need.
The spreadsheet gives you a great start on that tbh.

Thanks very much!
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s5fourdoor
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« Reply #34 on: February 27, 2013, 02:35:37 PM »

I've been trying to resolve something from the FR and I'm having no luck.

I've been comparing two WinOLS RS4 box, a tuner-pro k-box using prj's auto-K-xdf, and a tuner-pro m-box also using prj's auto-M-xdf.

Here's the problem.  I can't get correct LDDIMNN, LDDIMXN.  Can someone please assist me he here with details?

How would I search for this on my own, btw?

From my reading of the FR, we need these tables to be modified to get proper I control.
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s5fourdoor
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« Reply #35 on: February 27, 2013, 03:14:20 PM »

The FR says the following:

9. LDDIMNN: apply in the case of transitory problems arising from lighter dynamic response of around 5%, otherwise use the maximum value to deaden/nullify the function.

Thus with a value of 100 for all points in the stock m-box, this functionality is turned off...
The RS4 however appears to use LDDIMNN.
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AARDQ
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« Reply #36 on: February 27, 2013, 04:41:34 PM »

silentbob touched on LDDIMNN here:  http://nefariousmotorsports.com/forum/index.php?topic=315.30  Not much detail, alas.

My understanding in broad concept is that LDDIMNN is subtracted from the output I-value such that the I output is never allowed to drop below that value.  If it's set to 100, then I is permitted to drop to zero.

LDDIMXN is added to the output I value so that the limit is increased in the prescribed circumstances.

Again, my understanding, good for a laugh if nothing else.
« Last Edit: February 27, 2013, 04:52:20 PM by AARDQ » Logged
s5fourdoor
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« Reply #37 on: February 27, 2013, 04:48:07 PM »

OK.  So it's known that with the M-box values set to 100, this function is absolutely turned off.
You can see it quite clearly in the K-box, this function is absolutely used.
Toying with this stuff isn't simple or safe.  All of your axis maps and values need to exact and your list of variables super precise.

I feel I'm personally far from even copying the RS4 settings onto my K04S4 m-box setup... tbh.
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airtite
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« Reply #38 on: February 27, 2013, 11:23:15 PM »

would LDDIMNN apply to the med9 as well? So to drop KFLRAPP to 0 LDDIMNN must be set to 100?
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bbernd
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« Reply #39 on: February 28, 2013, 03:33:12 AM »

I think I have still a big misunderstanding at this point...

The N75 Duty cycle is a result of adding P, I and D value based on lde.

KFLDIMX is only the upper limit for I value at a given point.

So if actual boost reaches desired boost, lde will be zero.

So the components P, I and D are all multiplicated with zero and added to zero...  so duty cycle is zero...

So without LDDIMNN what keeps the N75 duty cycle up to the needed value (for example 75% in steady state, desired = actual and lde = 0)

I do not get it from reading the FR on and on again...
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AARDQ
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« Reply #40 on: February 28, 2013, 08:33:34 AM »

I think I have still a big misunderstanding at this point...

The N75 Duty cycle is a result of adding P, I and D value based on lde.


the CHANGE in duty cycle is a result of P, I and D.


 so duty cycle is zero...




No, the duty cycle merely doesn't change from where it was.  Everything's good assuming actual meets requested.


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bbernd
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« Reply #41 on: February 28, 2013, 09:26:08 AM »

the CHANGE in duty cycle is a result of P, I and D.

No, the duty cycle merely doesn't change from where it was.  Everything's good assuming actual meets requested.


Ok, that should be my big misunderstanding - I will read it again..  thx
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nyet
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« Reply #42 on: February 28, 2013, 09:38:53 AM »

Ok, that should be my big misunderstanding - I will read it again..  thx

No, you had it right. The DC is the sum of P I an D
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nyet
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« Reply #43 on: February 28, 2013, 09:39:24 AM »

I think I have still a big misunderstanding at this point...

The N75 Duty cycle is a result of adding P, I and D value based on lde.

KFLDIMX is only the upper limit for I value at a given point.

So if actual boost reaches desired boost, lde will be zero.

So the components P, I and D are all multiplicated with zero and added to zero...  so duty cycle is zero...

So without LDDIMNN what keeps the N75 duty cycle up to the needed value (for example 75% in steady state, desired = actual and lde = 0)

I do not get it from reading the FR on and on again...

I is not zero. if lde is zero. Read up on PIDs

the I-limit is the steady state requested PID output.
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ME7.1 tuning guide (READ FIRST)
ECUx Plot
ME7Sum checksum checker/corrrector for ME7.x

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 experience.
AARDQ
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« Reply #44 on: February 28, 2013, 12:52:04 PM »


KFLDIMX is only the upper limit for I value at a given point.


Missed this first time through.  KFLDIMX is a pilot value, not an upper limit.  It is the output under steady state conditions, and takes over from the PID under near-zero lde condition, if you will.  Follow ldimx output from the KFLDIMX logic in the FR.    The FR calls it a 'limit' but then says it 'describes the steady state duty cycle', "I- Begrenzung festlegen:
KFLDIMX: mit den station¨aren Tastverh¨altniswerten beschreiben." PDF page 874

There are other documents such as patents that describe the whole thing better than the FR.
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