MATLAB: How to find out z, p, and k of SISO transfer function of a plant

pid design

Dear All, I need to apply zpk command upon my plant just like an attached photo. My plant is given as:
num=[4.16];
den=[1 0.82 0.69];
G=tf(num,den)
what are the z, p, and k for my plant just like in given mathworks example https://www.mathworks.com/help/control/examples/designing-pid-for-disturbance-rejection-with-pid-tuner.html

Best Answer

In your example, the transfer function is defined from the zeros, poles and gain. In this case, zpk will return the same since the system is a second order system. Use the following lines instead:
z=roots(Gs.Numerator{1});
p=roots(Gs.Denominator{1});
k=Gs.Numerator{1};
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