siso.m

在鲁棒控制中

G=nd2sys([1 -2],[2 -1],-1);
minfo(G)
K1=1;
T1=formloop(G,K1,'neg','pos');
spoles(T1)
K2=nd2sys([1 1.9],[1.9 1]);
clp2=formloop(G,K2);
spoles(clp2)
K3=nd2sys([1.9 1],[1 1.9]);
clp3=formloop(G,K3);
spoles(clp3)
K4=nd2sys([1 2.5],[2.5 1]);
K4=mmult(K4,nd2sys([1.7 1.5 1],[1 1.5 1.7]));
clp4=formloop(G,K4);
spoles(clp4)

omega=logspace(-2,2,80);
G_g=frsp(G,omega);
K1_g=frsp(K1,omega);L1=mmult(G_g,K1_g);
K2_g=frsp(K2,omega);L2=mmult(G_g,K2_g);
K3_g=frsp(K3,omega);L3=mmult(G_g,K3_g);
K4_g=frsp(K4,omega);L4=mmult(G_g,K4_g);
vplot('nyq',L1,'-',L2,'--',L3,'-.',L4,'.'),add_disk
figure
axis([-4 1 -1 1])
vplot('bode',L1,'-',L2,'--',L3,'-.',L4,'.'),grid;