gusucode.com > MATLAB与控制系统仿真实践 源代码 > MATLAB与控制系统仿真实践 源代码/第十四章/eg14_12.m

    delta=6;
s=tf('s');
G=1500/s/(s+10)/(s+5);
figure(1)
margin(G)
figure(2)
step(feedback(G,1))
ex_pm=40;
phi=-180+ex_pm+delta;
[mag,phase,w]=bode(G);
wc=spline(phase,w,phi);
mag1=spline(w,mag,wc);
magdB=20*log10(mag1);
beta=10^(-magdB/20);
t=1/(beta*(wc/10));
Gc=(1+beta*t*s)/(1+t*s);
figure(3)
margin(Gc*G)
figure(4)
step(feedback(Gc*G,1))
G2=feedback(G*Gc,1);
[num2,den2]=tfdata(G2,'v');
t=0:0.01:10;
y2=step(num2,[den2,0],t);
plot(t,t,t,y2,':');grid
title('斜坡输入和滞后校正后系统的斜坡响应')
legend('斜坡输入','滞后校正后系统的斜坡响应');