After learning control systems for over half a year, I realize I don't quite understand the intuitive graphical representation of closed-loop transfer function:
https://preview.redd.it/0el3hmgwyws71.png?width=992&format=png&auto=webp&s=39d0c13b2515a162a5d798dd7b173751c2410ab1
Above is a screenshot from Wikipedia. Could someone explain in detail how this transfer function is derived?
Here is my confusion: 1. that "1" in the denominator really troubles my mind; 2. why is the output not equal to Z(s)G(s)? I thought this transfer function would have Z(s)G(s) in the numerator
How do I get the closed-loop transfer function of the system, fitted with a PID controller, if the input valve has a transfer function given by:
Q(s) / P(s) = Kv / (Tv∗S+I)
Where Kv is a constant of proportionality between the steady-state discharge and the pressure on the input valve. Tv is the time constant of the input valve.
I'm not sure how I'm meant to use the input valve transfer function to work out the closed-loop system transfer function.
Could anyone help explain the steps?
Need help understanding the what happened at the last step of the reduction of the closed loop system. Why did they multiple by 5? Is multiplying by 5 normalizing the transfer function? Can you multiple it by 10,15? Why is 5 the chosen number too, the question doesn't state anything with 5.
https://imgur.com/a/sbLLZkv
I'm really struggling with some coursework at the minute, I've got a closed loop system and I have to find its transfer function and the maximum value of K at which it's stable, but I'm getting weird values for K, doing the initial check shows that K needs to be both above and below 0 for it to be stable, so I know I've done something wrong somewhere.
Here's the coursework: https://imgur.com/a/1hC30 Here's what I've done: https://i.imgur.com/UaBQC5J.jpg
myfigure = figure ;
for i = 1:100
% plot something
if ~isvalid(myfigure)
break ;
end
end
This seems to work alone, but I want to turn it into a function.
I am able to identify the loop and can solve it using various circuit analysis techniques. The confusion that I have is whether to consider PMOS tail node of the differential pair as virtual ground or not when the feedback loop is broken and the input is grounded. My friends claim it to be a virtual ground but are unable to give adequate proof. I say it cannot be considered virtual ground as the inputs to the differential pair will not be differential. When the feedback loop is broken the input terminal will be grounded and a test signal is administered only to the other branch of the differential pair.
https://preview.redd.it/45m4f9aro9681.jpg?width=1600&format=pjpg&auto=webp&s=fd2bd7fd949c900e7ef54e4b11121bb369211855
what is the open and closed loop function of this system?
i found this in the text book.
i solved by:
1- found the closed loop function of just the part of B(p) and its "feedback", let's call it B'(p).
2- after that i did H(p) = A(p) / ( 1 + A(p) * B'(p) )
but in the textbook they solved with H(p) = A(p) * B(P) / ( 1 + A(P) * B'(p) )
so why do you think that is?
PS: sorry i am not familiar with English technical terms since we study in French here.
With the S42A V2 closed loop kit the driver is working mostly normal, with switches 1 and 2 in open loop it does the expected functions. In calibration is performs normal and finishes. With the 3rd switch on, the behavior gets weird, the motor sometimes moves 11 mm and stops with the red fail light on, but it will move in the opposite direction and return to green light. The problem is it's only moving a little when I send command and indicating error and then halts movement. I can't get this to home or do anything more than 10mm in closed loop mode. I mean, closed loop is active and it will auto-correct position but that's it. What am I missing?
My question is specifically referring to system/process identification. I was wondering if you were to approximate a system as a FOPDT model. Lets say for a step change 0-100 the time constant is tau=20s Kp=5 and theta=3. If linear approximation is a good approximation, should the same values of tau, Kp and theta be obtained for a step change of 0-25?
I hope this makes sense. Thank you to this sub for all the help.
Tried googling, most lead to other types of main fermentors.
I've fermented in the keg for the first time with a spunding valve, it's all ready to go tomorrow, just wondering what's the best way to transfer.
I've already "dry" hopped it in the fermentor keg. Serving keg will be CO2 purged.
Thinking I will just hook up the dip tubes together and put some pressure on the fermentor keg while alowing the serving keg to vent?
So as I’ve learned here the last few months of brewing - oxygen, is only good during aeration. While I’ve done my best to mitigate any kind of air during transfer to keg, it was this last beer where I felt I could’ve had a better result if I came up with a closed transfer.
I chose to modify my Fermonster and Big Mouth Bubblers with a gas post. Some low pressure CO2 and we’re in business.
I brewed an Australian IPA which is on the lighter side almost like a NEIPA, so I really wanted no oxygen this time around to keep the color.
I guess I’m ready to try my hand at a juicy/hazy/NEIPA in the near future.
Cheers guys and gals!
https://i.imgur.com/AZ0yT2p.jpg
https://i.imgur.com/pmBLoA1.jpg
https://i.imgur.com/aOm5U0b.jpg
And the beer sample (finished are 6.4%)
https://i.imgur.com/SGIRuvi.jpg
My supervisor has told me the current control loop of IM contains a PI controller (Kp+Ki/s) and IM model (Km/(Tm*S+1), Km = 1.0/R Tm=(Ls-Lm*Lm/Lr)/R). HOW CAN I DERIVE THIS?
He also says there's a similar equation for the speed controller. My guess is speed control will be include J inertia and D friction?? HOW CAN I DERIVE THIS?
Any good papers?
It’s late so this is probably a stupid question, but I want to perform a closed-loop transfer from a table mounted Grainfather conical fermenter’s dual valve to a keg on the floor. Can’t I just connect the dual valve sampling port on the fermenter to the keg’s gas in line? If not and I need to connect the gas in line to the fermenter and the dual valve to the keg’s liquid in post, then would something like this work for connecting the gas line to the fermenter lid?
If that modified tri clamp is necessary, how can I add an air lock and/or a blow off tube to the ball lock post?
Last on this subject, how do you perform a closed-loop transfer of a carbonated beer without a drop in pressure resulting in foam?
Unrelated, but I thought I’d ask: how often (if ever) and how do you clean your gas lines?
Thank you!
https://i.stack.imgur.com/ghPqk.png
i found this in the text book.
i solved by:
1- found the closed loop function of just the part of B(p) and its "feedback", let's call it B'(p).
2- after that i did H(p) = A(p) / ( 1 + A(p) * B'(p) )
but in the textbook they solved with H(p) = A(p) * B(P) / ( 1 + A(P) * B'(p) )
so why do you think that is?
this is a screenshot of the textbook solution
https://i.stack.imgur.com/N98JV.png
the writing is in French, so please ask if you wanna a little explication
PS: sorry i am not familiar with English technical terms since we study in French here.
