G=tf(10,[1,10,35,50,24]);
[Kc,pp,wg,wp]=margin(G);Tc=2*pi/wg;
[Gc1,Kp1]=ziegler(1,[Kc,Tc,10]);Gc1
[Gc2,Kp2,Ti2]=ziegler(2,[Kc,Tc,10]);Gc2
[Gc3,Kp3,Ti3,Td3]=ziegler(3,[Kc,Tc,10]);Gc3
G_c1=feedback(G*Gc1,1);step(G_c1);hold on
G_c2=feedback(G*Gc2,1);step(G_c2);
G_c3=feedback(G*Gc3,1);step(G_c3);