pid_zn.m

-PID controller has been extensively used in the industrial world. But in this controller it is dif

den1=[1 6 11 6 0];
num1=[1];
sysrl=tf(num1,den1);
%Transfer function of the Root Locus PID controller
den_pid=[1 0];
num_pid=[4.74 6 1.91]; %Kd Kp Ki
rl_pid=tf(num_pid,den_pid);
%Placing PID controller in unity feedback system with 'sysrl'
sys1=series(rl_pid,sysrl);
rl_sys=feedback(sys1,[1]);
figure(1)
hold on
step(rl_sys,'r',0:0.01:30);%Red-Root locus
hold off
title('Green : Genetic Algorithm  ,  Red : Zeigler Nichols Criterion')
disp(' Zeigler Nichols values :  Kd = 4.74 , Kp = 6 , Ki = 1.91');
grid