G=tf(1,[1,3,3,1]); Ti=1; Td=1; Kp=1; N=10;
no=Kp*([Ti*Td,0,0]+conv([Ti,1],[Td/N,1]))/Ti;
do=[Td/N 1 0]; Gc=tf(no,do);
G_c=feedback(G*Gc,1);
step(G_c), hold on
nH=[(1+Kp/N)*Ti*Td,Kp*(Ti+Td/N),Kp]; 
dH=Kp*conv([Ti,1],[Td/N,1]); 
H=tf(nH,dH); Gc1=tf(Kp*[Ti,1],[Ti,0]);
G_c1=feedback(G*Gc1,H); step(G_c1)