PID - Root Locus (Sisotool) for Transfer Function with Zeros and Poles

In summary, it is possible to stabilize the transfer function by adding zeros and poles, but it may require some experimentation and possibly a more advanced type of controller.
  • #1
Brian1776
1
0
Hi everyone! I have a 8th order transfer function, you can see it in the first image:

% Transfer function
num = [2.091,0,203.3,0,-2151,0,-1.072e05];
den = [1,0,-830.4,0,-1.036e05,0,-5.767e05,0,2.412e07];
tf = tf(num, den)

tf.png

rootlocus.png

I need to use a PID, so I'm trying to use a compensator, adding poles and zero with the sisotool in MatLab to turn it stable. But iI tried, I tried, and tried, without success. How you can see in picture bellow. But the zero on the right side always holds a pole.
Note: Red zeros and poles have been added, and blue ones belong to the original transfer function.

sisotool2.png


My question is:
Is it possible stable this function adding zeros and poles, or not ?

Any tips ?
Note: I must use a PID for this lesson :(
 
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  • #2
Yes, it is possible to stabilize the transfer function by adding zeros and poles. However, it may take some trial and error to find a configuration that works. You may want to experiment with different combinations of zeros and poles, as well as adjusting the parameters of the PID controller. Additionally, you may want to consider using a more advanced type of controller, such as an Adaptive Control, which is designed to automatically adjust itself based on feedback from the system.
 

FAQ: PID - Root Locus (Sisotool) for Transfer Function with Zeros and Poles

What is PID?

PID stands for Proportional-Integral-Derivative. It is a control algorithm used in engineering and science to regulate a system's output based on its error signal.

What is Root Locus?

Root Locus is a graphical representation of a system's poles and zeros in the complex plane. It is used to analyze the stability and performance of a control system.

What is Sisotool?

Sisotool is a MATLAB tool used for designing and analyzing control systems. It provides a user-friendly interface for plotting root locus, calculating controller parameters, and simulating closed-loop responses.

How do I use Sisotool to design a PID controller?

To design a PID controller using Sisotool, you first need to obtain the transfer function of your system. Then, open Sisotool and import the transfer function. Next, you can use the graphical tools to adjust the controller parameters and plot the root locus to analyze the system's stability and performance. Finally, you can simulate the closed-loop response to see how the controller affects the system's output.

What is the significance of zeros and poles in a transfer function?

Zeros and poles are important components of a transfer function. Zeros are the values of the independent variable that make the numerator of the transfer function equal to zero, while poles are the values that make the denominator equal to zero. They provide information about the behavior and stability of the system, and they are used in designing controllers to improve the system's performance.

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