u=zeros(4,1);
y=zeros(3,1);
e=zeros(4,1);
a=[0,0.368,0];
b=[0,0,0,0.632];
c=[0,0.6065,0,0.3935];
d=[0.9226,-0.1291,0,0];     %0.6226改為0.9226，-0.2291改為-0.1291
yk=0;
yt=0;
t=0;
x=0:0.5:30
r=cos(x);
ek=0;
for k=1:60
    ek=r(k)-yk;
    e=[ek;e(1:3)];
    uk=c*u+d*e;
    u=[uk;u(1:3)];
    yk=a*y+b*u;
    y=[yk;y(1:2)]; 
    yt=[yt,yk];
    t=[t,k*0.5];
end
figure;
plot(t,yt,'r')
legend('cos跟蹤');
grid on