MS2 Boost control - Am I missing something?
05-18-2015, 02:46 PM
#41
Boost Czar
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seems really high for the I value, you shouldn't be over like 40-50 on any value--MAYBE D. that's what causing it.
start I at 0 and increase until it can hold the target to redline--its long term tracking.
aidandj gets props for the drop shadowed screenshot.
start I at 0 and increase until it can hold the target to redline--its long term tracking.
aidandj gets props for the drop shadowed screenshot.
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05-18-2015, 02:49 PM
#43
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Wait a miniute, I'm dumb. I meant P, not I. I have I and D set at zero right now, I've been following this, starting at 150 and working down.
To Tune PID:
1. Set Integral and Differential Gains to 0% - To make tuning the Proportional gain easier, set the Integral and Differential gains to 0%.
2. Set Proportional gain to 150% and slowly lower - While tuning Proportional gain, higher numbers mean slower boost climb and lower final boost. For safety, start with a very high gain (150% should be sufficient). Find the RPM that typically spools quickly, and fully and quickly depress the accelerator. Note how much boost is reached. If boost overshoots the target, increase the Proportional gain. Otherwise, reduce the Proportional gain and try again. Do this until boost reaches the target with little or no overshoot.
3. Tune the Integral Gain - The next step after the target is reached consistently is to tune the Integral gain. Starting from the RPM used to tune the P-gain, fully depress the accelerator and watch the boost as the engine climbs through the RPM range. As the engine accelerates through the rev range, the boost will probably creep away from the target. Keep increasing the I gain until the controller adequately maintains the target with minimal oscillation.
4. Tune the Derivative Gain - If overshoot cannot be tuned out with the P gain on a quick acceleration, increase the D gain until the overshoot is minimized. Care must be taken when increasing the D gain as too much D gain can over-dampen the effects of the P and I gains.
No basic mode, does that slider do anything in PID mode? In MS2 that's all you get with basic AFAIK.
To Tune PID:
1. Set Integral and Differential Gains to 0% - To make tuning the Proportional gain easier, set the Integral and Differential gains to 0%.
2. Set Proportional gain to 150% and slowly lower - While tuning Proportional gain, higher numbers mean slower boost climb and lower final boost. For safety, start with a very high gain (150% should be sufficient). Find the RPM that typically spools quickly, and fully and quickly depress the accelerator. Note how much boost is reached. If boost overshoots the target, increase the Proportional gain. Otherwise, reduce the Proportional gain and try again. Do this until boost reaches the target with little or no overshoot.
3. Tune the Integral Gain - The next step after the target is reached consistently is to tune the Integral gain. Starting from the RPM used to tune the P-gain, fully depress the accelerator and watch the boost as the engine climbs through the RPM range. As the engine accelerates through the rev range, the boost will probably creep away from the target. Keep increasing the I gain until the controller adequately maintains the target with minimal oscillation.
4. Tune the Derivative Gain - If overshoot cannot be tuned out with the P gain on a quick acceleration, increase the D gain until the overshoot is minimized. Care must be taken when increasing the D gain as too much D gain can over-dampen the effects of the P and I gains.
No basic mode, does that slider do anything in PID mode? In MS2 that's all you get with basic AFAIK.
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05-18-2015, 02:52 PM
#45
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I think this run was at I125 or I130 or thereabouts, I was starting to subtract a bit form each run to get the overspool I want before I went home for the night. Do you have an initial overshoot, or at least one tuned out?
Need to go back out again, more tuning
Do you remember where you were getting this T3 to spool Scott? I'm pretty impressed for a <$200 5K+mi turbo.
Need to go back out again, more tuning
Do you remember where you were getting this T3 to spool Scott? I'm pretty impressed for a <$200 5K+mi turbo.
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05-18-2015, 03:16 PM
#52
SADFab Destructive Testing Engineer
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You should use the slider first then use the PID.
Quotes from Ken, the dev:
Quotes from Ken, the dev:
Technically it [the slider] affects how sensitive it is to changes in input. The input and target get converted to a percentage, the more sensitive, the larger that percentage changes given a particular change in boost. Think of it as a gain that affects all three PID gains at the same time by the same amount.
Changing between 1 and 0 shouldn't make that much difference... All that says to me is that it's a lot too sensitive... The change I'm planning to do is basically at the end of the PID calcs there's a division that divides off all the extra digits (we control the valve in 1% increments, but the internal calculations start at .01% precision... when the PID gains are multiplied in, that essentially multiplies it to .0001 precision, then that gets divided off at the end). I may have done the math wrong, or even if I did it right it might be a little to sensitive to be practical. So I can add a 0 to the end of the divisor there which should reduce the sensitivity by 10x and make the slider actually useful again.
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05-18-2015, 03:31 PM
#53
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That's how I saw it, but when I had slider even at 0, I would still get wild oscillations. However, this was with delta at 14, and intervals at 20ms... it could have been those factors that made the slider ineffective.
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05-18-2015, 07:17 PM
#55
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Just for *****, here is a 4th gear pull from 55 mph, then shifting to 5th and goin a little more:
Any idea what I can do to help lessen that dip after I get into 5th?
Here is the settings I currently run:
Any idea what I can do to help lessen that dip after I get into 5th?
Here is the settings I currently run:
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05-18-2015, 07:48 PM
#57
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I was tuning I this morning, and the boost was getting more stable the higher "I" was.
Haven't really messed with the slider tho.
Was thinking possibly tweaking the initial boost duty in that particular area might help too.
Haven't really messed with the slider tho.
Was thinking possibly tweaking the initial boost duty in that particular area might help too.
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05-18-2015, 07:56 PM
#59
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Side note: Target is 15psi, it peaks at 15.1, dips to about 14.1 and then stabilizes around 14.7~14.8 so the dip isn't that significant...
I'll try adding some D by what, 5 points at a time and see what happens?
I'll try adding some D by what, 5 points at a time and see what happens?
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