ex8_11.m

反馈控制系统设计与分析（matlab程序）

G=tf(100,[1,7,2]); W=tf(100,[1,1]); 
[Gc,tau]=minsens(G,W,[0.001,1]);

tau, zpk(Gc)

G_o=G*Gc; G_c=feedback(G_o,1); step(G_c,0:0.00005:0.02)

[Gc1,tau]=minsens(G,W,[0.001,1]);

G_c1=feedback(G*Gc1,1); 
step(G_c1,0:0.00005:.01); hold on
[Gc2,tau]=minsens(G,W,[0.001,1]);

G_c2=feedback(G*Gc2,1); step(G_c2,0:0.00005:.01); 

g1=feedback(1,G*Gc); [m1,p1,w]=bode(g1); 
g2=feedback(1,G*Gc1); [m2,p2]=bode(g2,w);
g3=feedback(1,G*Gc2); [m3,p3]=bode(g3,w);
[m,p]=bode(W,w); 
m1=20*log10(m1(:)'); m2=20*log10(m2(:)'); 
m3=20*log10(m3(:)'); m=20*log10(m(:)');
semilogx(w,m,'-',w,m1,'--',w,m2,':',w,m3,'-.'), 
figure; semilogx(w,m+m1,'--',w,m+m2,':',w,m+m3,'-.')