MS2 V3.0 Boost control algorithm issue.
Hi guys, I've installed a new MAC solenoid for my internally gated gt2871, I'm tuning the PID controller but it's really not behaving as it should. Below are my tuner studio settings as well as a part of the log that shows the boost duty and target.
Considering the parameters, especially the derivative set to: 0, Boost duty shouldn't have fallen as the MAP was below the target, both P and I gains should increase, not decrease. Tell me what I'm doing wrong. https://cimg2.ibsrv.net/gimg/www.mia...7bacba781a.png https://cimg3.ibsrv.net/gimg/www.mia...081f54be51.png |
Depending on how you connected your solenoid (default open or default closed), you might have to flip the closed and open duty.
Also: Don't tell me you are doing all of this without a functioning wideband... |
The polarity is fine, it does rise and lower the boost as it should, but the derivative behaviour of the pid algorithm is not as it should be, only having coefficients for proportional and integrating while derivative is 0 it should first cross the boost target before lowering the duty.
also, my wideband died, but the map is fully tuned. |
Originally Posted by fleka
(Post 1483948)
Hi guys, I've installed a new MAC solenoid for my internally gated gt2871, I'm tuning the PID controller but it's really not behaving as it should. Below are my tuner studio settings as well as a part of the log that shows the boost duty and target.
Considering the parameters, especially the derivative set to: 0, Boost duty shouldn't have fallen as the MAP was below the target, both P and I gains should increase, not decrease. Tell me what I'm doing wrong. Trying to use closed loop boost control on a MS2. |
Originally Posted by sshamrockk
(Post 1484067)
Trying to use closed loop boost control on a MS2.
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I tried to tune mine, Vlad gave me tips and told me how, and i just couldnt get it to work, either made 10 psi or 18+ psi, there was like no inbetween.
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Have you characterized this open loop yet? That is where you start. Turn off boost tolerance, reduce sensitivity, read the instructions, ...
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And when you finally get there, reducing P is actually more aggressive with this algorithm. Start at 100 and go down.
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Originally Posted by Ted75zcar
(Post 1484454)
And when you finally get there, reducing P is actually more aggressive with this algorithm. Start at 100 and go down.
However I think I'm gonna try and do it with initial duty table as it seems this is not an actual PID controller, but something similar. |
Originally Posted by fleka
(Post 1484460)
I've simulated the source code for boost control in Matlab, it doesn't add up to what's happening in the car, given the same exact variables the pid gives me 100% duty when simulatedin Matlab with the same data, while the car lowers from 100 to 85% duty...
However I think I'm gonna try and do it with initial duty table as it seems this is not an actual PID controller, but something similar. either way, good for you. |
Originally Posted by sshamrockk
(Post 1484189)
I tried to tune mine, Vlad gave me tips and told me how, and i just couldnt get it to work, either made 10 psi or 18+ psi, there was like no inbetween.
Let's see if you can somehow figure it out. Also about PID: There were different FW versions for the ms2 over the years, and each had a different approach to how the PID settings worked. Just to further screw everything up for anyone trying to "solve" this now. I usually just tell ms2 owners to stick to MBC |
Originally Posted by Ted75zcar
(Post 1484470)
you simulated the MegaSquirt algorithm, or a traditional PID? MS does not use a traditional PID.
either way, good for you. |
that's a good start. at least then you're starting with known operation for each of the 3
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Originally Posted by 18psi
(Post 1484501)
that's a good start. at least then you're starting with known operation for each of the 3
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MS2 EBC can be made to work, it just takes work. IMO you HAVE to start with open loop tuning of the initial duty table and open/closed duty fields for the solenoid. I feel like a broken record on this one, but the Boost Tolerance functin NEVER did anything that I considered beneficial.
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we did that. it didn't work. in various fw's the pid's went up from zero, then down from 200 iirc, and other variations.
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yeah, guess I should add that you need to be on 3.4.2
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