MS-II Closed Loop Boost Control - PID
01-26-2010, 09:32 AM
#1
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MS-II Closed Loop Boost Control - PID
Any of you guys having good luck with the new code? I'm just starting to fool around with it this week and was hoping to get a better starting off point with my PID values.
Currently I'm running:
Proportional Gain(%) - 130
Integral Gain(%) - 35
Differential Gain(%) - 60
It has been suggested in order to tune you should:
I have my boost targets set to 14.5psi, and I'm really close to hitting it initially but it's tapering off as the revs increase.
I assume I just need to starting increasing the I value until it stops tapering off, and maybe just increase P to hit a higher target.
Thought? Tips? Free Hugs?
(ignore my duty cycle values, as you can see I'm going crazy rich in boost on purpose)
Currently I'm running:
Proportional Gain(%) - 130
Integral Gain(%) - 35
Differential Gain(%) - 60
It has been suggested in order to tune you should:
First, turn off all I.
Second, Adjust P higher. Keep going higher until it gets close to your boost without overshooting (a little overshoot is OK here).
Once you get to this point, adjust the I term until the code will hold your target boost across the rev range.
Last, adjust the D term to get rid of any leftover overshoot, and to help with any oscillation that might pop up.
Second, Adjust P higher. Keep going higher until it gets close to your boost without overshooting (a little overshoot is OK here).
Once you get to this point, adjust the I term until the code will hold your target boost across the rev range.
Last, adjust the D term to get rid of any leftover overshoot, and to help with any oscillation that might pop up.
I assume I just need to starting increasing the I value until it stops tapering off, and maybe just increase P to hit a higher target.
Thought? Tips? Free Hugs?
(ignore my duty cycle values, as you can see I'm going crazy rich in boost on purpose)
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01-26-2010, 10:50 AM
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Just as you said - I would adjust P a wee bit lower and then I a bit higher to keep it on the target. I really don't know about the D. (Didn't really do a lot to me)
My values at the moment are:
P= 105 I=48 D=150 (ignore that) - still seems to overshoot a bit but keeps quite good to the target.
Now give me a hug...
Greets
My values at the moment are:
P= 105 I=48 D=150 (ignore that) - still seems to overshoot a bit but keeps quite good to the target.
Now give me a hug...
Greets
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01-26-2010, 05:22 PM
#9
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Here's what I don't like: Driving home I settle on P - 150 I - 40 and D - 60, holds 14.3psi flat in a 4th gear pull from 3K to 5.5K, looking good; my target is 14.5psi. Stop at a light, give it hell in second and it's only holding like 13psi...that's why I pulled my EBC in the first place...
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01-27-2010, 02:11 AM
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Here's what I don't like: Driving home I settle on P - 150 I - 40 and D - 60, holds 14.3psi flat in a 4th gear pull from 3K to 5.5K, looking good; my target is 14.5psi. Stop at a light, give it hell in second and it's only holding like 13psi...that's why I pulled my EBC in the first place...
If that overshoots in the beginning you could up the D value.
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01-27-2010, 08:35 AM
#15
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Yeah I went the wrong way, mistaking P for I. I'm finished with P=110 I=53 D=47 by the time I got to work this morning, it's hitting my target then around 4K it starts to fade off. I'll keep at it but I don't have very many stretches of road where I can give it boost so it's going to take a while 
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01-27-2010, 11:18 AM
#18
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Effects of increasing a parameter independently
Stole this from wiki, shows the relationship of increasing a value, should help for tuning if you understand these relationships.
also, looks like the tuning method I first posted is the Ziegler-Nichols method of tuning. Should be a good way to start from scratch, basically: Start with everything zeroed out. Then increase only P until you achieve your boost target, then increase I to hold the target throughout, and then increase D to remove initial overshoot and oscillation.
Code:
Prmtr Rise time Overshoot Settling time Steady-state error P Decrease Increase Small change Decrease I Decrease Increase Increase Large Decrease D Sm. decrease Sm. decrease Sm. decrease No effect
also, looks like the tuning method I first posted is the Ziegler-Nichols method of tuning. Should be a good way to start from scratch, basically: Start with everything zeroed out. Then increase only P until you achieve your boost target, then increase I to hold the target throughout, and then increase D to remove initial overshoot and oscillation.
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01-27-2010, 01:51 PM
#20
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I suck at this. I cant do anything to get the boost from not tapering off. If I look on logs the Duty Cycle is "increasing" but I believe the settings in TS are set to "inverted," so I figure it's actually trying to dump boost off.
I guess I need to start from scratch with everything zeroed and work from there.
I just tried P=30 I=0 D=0 and It hit 16.5psi and tapered of to 13psi.
So I'll keep increasing P and work from there. It seems the P% value is too low and it's not reacting quick enough.
However, at same time P=107 I=75 D=45 let me hit 14psi (14.5 target), rising up to 15.5, then tapering off to 12psi. When I tried more I (100) it really didn't help the tapering off effect.
My wastegate holds 11psi flat right now. Would it be good to set a smaller open and closed % in the main parameters so it doesn't run the valve at such a large range? I probably need like 20-40% DC.
I guess I need to start from scratch with everything zeroed and work from there.
I just tried P=30 I=0 D=0 and It hit 16.5psi and tapered of to 13psi.
So I'll keep increasing P and work from there. It seems the P% value is too low and it's not reacting quick enough.
However, at same time P=107 I=75 D=45 let me hit 14psi (14.5 target), rising up to 15.5, then tapering off to 12psi. When I tried more I (100) it really didn't help the tapering off effect.
My wastegate holds 11psi flat right now. Would it be good to set a smaller open and closed % in the main parameters so it doesn't run the valve at such a large range? I probably need like 20-40% DC.
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