num=[1,-1]; den=[1,2,1]; G=tf(num,den);
nW=0.62*[1,1.2,1]; dW=conv([1,0.001],conv([1,1.2],[0.001,1]));
[a,b,c,d]=tf2ss(num,den); S=mksys(a,b,c,d);
W1=[0,nW; dW]; TSS_2=augtf(S,W1,[1e-5;1],[]);
[gg,Fopt]=hinfopt(TSS_2);

[af,bf,cf,df]=branch(Fopt); Gc1=zpk(ss(af,bf,cf,df))

G_o1=G*Gc1; G_c1=feedback(G_o1,1);
step(G_c1), 
figure, ngrid('new'), nichols(G_o1), axis([-360,0,-40,40])