% ex5_17
% 離散控制系統(tǒng)的根軌跡
figure('pos',[50,50,250,200],'color','w');
axes('pos',[0.1,0.16,.8,.8]);
G=tf([0.5151 -0.1452 -0.2963 0.05284],[1 -2.3679 1.7358 -0.3679 0])
rlocus(G);
axis([-3 1 -1.5 1.5]);
hold on;
t=0:0.1:2*pi;
x=sin(t);
y=cos(t);
plot(x,y,':')