1、t = 0:0.01:10;nG=0.5 1 10;dG=4 5 20;G1=tf(nG,dG);nG=1 2 20;dG=5 9 40;G2=tf(nG,dG);nG=2 4 40;dG=6 17 80;G3=tf(nG,dG);y1,T=impulse(G1,t);y1a,T=step(G1,t);y2,T=impulse(G2,t);y2a,T=step(G2,t);y3,T=impulse(G3,t);y3a,T=step(G3,t);subplot(121),plot(T,y1,-,T,y2,-,T,y3,)legend(kb=5,kb=10kb=20xlabel(t(sec),yl
2、abel(x(t);grid on;subplot(122),plot(T,y1a,T,y2a,T,y3a,(2)当Kb分别为5、10、20时,系统的瞬态性能指标程序和数据t=0:yss=0.5;dta=0.02;y1=step(G1,t);y2=step(G2,t);y3=step(G3,t);r=1;while y1(r)0.5-dta&y1(s)0.5+dta;s=s-1;ts1=(s-1)*0.01;while y2(r)y2(s)ts2=(s-1)*0.01;while y3(r)y3(s)=-3;n=n+1;Wb=w(n)2.3利用Matlab分析系统的稳定性den=4 5 20;
3、K=10;num1=K;Gm1 Pm1 Wg1 Wc1=margin(num1,den);K=100;num2=K;mag, phase,w=bode(num2,den);Gm2 Pm2 Wg2 Wc2=margin(mag, phase,w);20*log10(Gm1) Pm1 Wg1 Wc1;20*log10(Gm2) Pm2 Wg2 Wc2den=5 9 40;den=6 17 80;2.4利用Matlab设计系统校正校正前系统的Bode图和程序k=10numg=0.5 1 10;deng=4 5 20;num,den=series(k,1,numg,deng);%w=logspace(
4、-1,2,200);mag,phase,w=bode(tf(num,den),w);Gm,Pm,Wcg,Wcp=margin(mag,phase,w);Phi=(50-Pm+5)*pi/180;alpha=(1-sin(Phi)/(1+sin(Phi);M=10*log10(alpha)*ones(length(w),1);semilogx(w,20*log10(mag(:),w,M);校正后系统的Bode图和程序k=10;numgc=0.081 1;dengc=0.186 1;nums,dens=series(numgc,dengc,numg,deng);num,den=series(k,1,nums,dens);bode(tf(num,den),w);grid;title(相位裕度=,num2str(Pm);