Author Topic: PID Regulator  (Read 1083 times)

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Offline nForceTopic starter

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PID Regulator
« on: September 09, 2019, 07:50:39 pm »
Can a PID Regulator have two or more feedback loops? For example, if we are measuring process variable which has negative values and positive.
 

Offline Yansi

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Re: PID Regulator
« Reply #1 on: September 09, 2019, 08:12:51 pm »
Not sure if I understand you correctly.

Regulator can regulate regardless the sign of the value.
 
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Offline MosherIV

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Re: PID Regulator
« Reply #2 on: September 09, 2019, 08:24:33 pm »
Quote
Can a PID Regulator have two or more feedback loops? For example, if we are measuring process variable which has negative values and positive.
My understanding is no. PID only has a single control loop.
There are 2 ways to go about PID.
1. Manually tune the PI parameters to get best response then tweek the D.
2. Characterise the open loop transfer equation of the system, so that you can use for the closed loop equation.

With the 2 option, you can have as many inputs as you like. They will just boil down to a simple multiplier or an offset constants. This sounds like the 'negative values and positive'.
There is however only a single feedback loop.
 
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Online IanB

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Re: PID Regulator
« Reply #3 on: September 09, 2019, 08:29:39 pm »
Can a PID Regulator have two or more feedback loops? For example, if we are measuring process variable which has negative values and positive.

One loop controls one variable. If you have two variables to control you will need two loops. It is possible for two loops to interact with each other, in which case more advanced strategies may be required.

Your question about negative and positive values is hard to understand. It is still a single process variable.
 
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Offline Dave

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Re: PID Regulator
« Reply #4 on: September 09, 2019, 08:35:47 pm »
Please be more specific with your question. It's very hard to give you any sort of meaningful answer (or alternative solution) to your problem if you're being vague.
<fellbuendel> it's arduino, you're not supposed to know anything about what you're doing
<fellbuendel> if you knew, you wouldn't be using it
 
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Offline nForceTopic starter

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Re: PID Regulator
« Reply #5 on: September 11, 2019, 04:45:58 pm »
Sorry guys. Here is the thing:

I would like to control a synhrounous motor, which works as a motor and a generator. So our measurement of torque has negative and positive values. My question is at the PID regulator, how would I create a proper PID regulator such that  it would regulate properly. The PID regulator has the output torque, reference torque of course.

I know that reference torque subtract from actual torque.
 

Offline Yansi

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Re: PID Regulator
« Reply #6 on: September 11, 2019, 07:02:26 pm »
PID regulator does not give a turd, whether the value of y(t) is positive or negative. The error value is still e(t) = r(t) - y(t).

You should start studying hard, if you want to spin a synchronous motor. 
 


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