Intergral Windup method in PID control

Thread Starter

Vindhyachal Takniki

Joined Nov 3, 2014
594
1. Trying to write PID control for temperature maintain in oven. We are doing it Pb,Ti & Td.

2. Now I see sometimes I am able to maintain temperature to setpoints.

3. Problem happens when intergral grows to large values. I am reading on internet there are many ways available. I tried clamping method to try clamp to some values, but it dont work, for some cases it work and some it dont, i.e for every setpoint clamp value is different to maintain temperature. Higher the setpoint higher the clamp value required.
Currently I am doing by hit and trial, but its not final solutions

4.Any one have experiecne which methods work best for this type of applicaiton?

5. I have seen two most common are:
a) Back calculations: but found most of matlab implementations, trying to find c implemenation
b) second is this: but dont know how to calculate AR band

1592321235892.png

c) Any other better method?
 

crutschow

Joined Mar 14, 2008
34,283
You could clamp the integrator (capacitor if analog) value to zero until the temperature is near the desired set point and the signal error is small.
You might have to experimentally determine what value of "small" works best.
That should minimize integrator windup problems.

For future designs you might consider using the digital Fuzzy Logic method for feedback control, which uses no integrators, and thus has no windup problems.
It uses a series of If-Then-Else states for feedback control
It's generally more intuitive to use and handles non-linear systems more readily than PID (which was developed for analog control loops and is predicated on the system being linear).
 
Last edited:
Top