1、2、时域分析k=200 时：程序如下k=200; G1=tf(5*k,1 345 5*k);t=0:0.1:5;figure(1)step(G1,t);gridxlabel(t);ylabel(c(t);title(step response)figure(2)impulse(G1,t);gridxlabel(t);ylabel(c(t);title(impulse response)impulse responset (sec)c(t)0 1 2 3 4 500.511.522.5System: G1Peak amplitude: 2.2At time (sec): 0.10 1 2 3 4
2、 500.20.40.60.81 step responset (sec)c(t)K=300:0 1 2 3 4 500.20.40.60.81 step responset (sec)c(t)0 1 2 3 4 500.511.522.53impulse responset (sec)c(t)K=100 时：0 1 2 3 4 500.20.40.60.81 step responset (sec)c(t)0 1 2 3 4 500.511.5 impulse responset (sec)c(t)3、根轨迹分析（程序如下）1)求系统传函：G1=tf(1 1.5 0.5,1 0);G2=tf
3、(1,100 215 30.5 1);H3=1;sys1=series(G1,G2);得传函：G3= s2 + 1.5 s + 0.5-100 s4 + 215 s3 + 30.5 s2 + s 2)绘制根轨迹程-2.5 -2 -1.5 -1 -0.5 0-1-0.8-0.6-0.4-0.200.20.40.60.81 Pole-Zero MapReal AxisImaginary Axis序如下：根轨迹图像如下：-2 -1.5 -1 -0.5 0 0.5-5-4-3-2-1012345 Root LocusReal AxisImaginaryAxis系统传函为：G= 280 s2 + 420
4、 s + 140-100 s4 + 215 s3 + 310.5 s2 + 421 s + 140K=280 时，阶跃响应曲线如下：程序如下：G=tf(0.5 0.75 0.25,100 365 404 157.3 20 2 0.25);t=0:0.01:40;figure(1)step(G,t);gridxlabel(t);ylabel(c(t);t itle(step response);0 5 10 15 20 25 30 35 4000.20.40.60.811.21.41.61.82 step responset (sec)c(t)注：临界振荡时 K= 153.3165第一个比较点之前放前置滤波器， K=280，阶跃响应曲线0 100 200 300 400 500 600 700 800 900 1000-1.5-1-0.500.51x 104 step responset (sec)c(t)扰动信号传函为： 100 s5 + 365 s4 + 403 s3 + 154.3 s2 + 16.75 s + 0.5-100 s4 + 215 s3 + 31.5 s2 + 2.5 s + 0.5
