(a) \(G(s)=\dfrac{\omega_n^2}{s(s+2\zeta\omega_n+K_t\omega_n^2)}(\omega_n=1,\zeta=0.2,K_t=0.1)\) (b) \(G(s)=\dfrac{\omega_n^2}{s(s+2\zeta\omega_n+K_t\omega_n^2)}(\omega_n=1,\zeta=0.2,K_t=1.5)\)
图 5-66 系统开环对数频率特性(MATLAB)
(a) \(G(s)=\dfrac{\omega_n^2}{s(s+2\zeta\omega_n+K_t\omega_n^2)}(\omega_n=1,\zeta=0.2,K_t=0.1)\) (b) \(G(s)=\dfrac{\omega_n^2}{s(s+2\zeta\omega_n+K_t\omega_n^2)}(\omega_n=1,\zeta=0.2,K_t=1.5)\)
图 5-67 系统单位阶跃响应(MATLAB)
MATLAB 文本：exe542b.m
wn=1;keth=0.2;Kt1=0.1;Kt2=1.5;
G1=tf(wn^2,conv([1,0],[1,2*keth*wn+Kt1*wn^2]));
G2=tf(wn^2,conv([1,0],[1,2*keth*wn+Kt2*wn^2]));
close1=feedback(G1,1);
close2=feedback(G2,1);
figure(1);margin(G1);grid;
figure(2);margin(G2);grid;
figure(3);step(close1);grid;
figure(4);step(close2);grid;
(3) 对于图 5-63(c),系统的开环传递函数为
\[G_3(s)=\dfrac{\omega_n^2(1+K_ds)}{s(s+2\zeta\omega_n)}=\dfrac{1+K_ds}{s(s+0.4)}\]
则开环频率特性为