用MATLAB画零极点图.

用MATLAB将传递函数化为零极点增益模型并绘制零极点图将传递函数化为零极点增益模型并绘制零极点图•num=[328];•den=[13842];•G=tf(num,den)•Transferfunction:•3s^2+2s+8•-----------------------------•s^4+3s^3+8s^2+4s+2••G1=zpk(G);•z=G1.z;•p=G1.p;•Z=z{:};•P=p{:};•k=G1.k;•pzmap(G);•pzmap(G1);•gridon将传递函数化为零极点增益模型并绘制零极点图•Transferfunction:•3s^2+2s+8•-----------------------------•s^4+3s^3+8s^2+4s+2•将上式化为零极点增益模型，并绘制零极点图。•num=[328];•den=[13842];•G=tf(num,den)求传递函数。命令后无“;”则屏幕立即显示，否则不显示。Transferfunction:3s^2+2s+8-----------------------------s^4+3s^3+8s^2+4s+2•G1=zpk(G);%化为零极点增益形式•z=G1.z;%将G1零点存入z•p=G1.p;%将G1极点点存入p•k=G1.k;%将G1增益存入kZ=z{:}Z=-0.3333+1.5986i-0.3333-1.5986iP=p{:}P=-1.2496+2.2082i-1.2496-2.2082i-0.2504+0.4980i-0.2504-0.4980i显示零点显示极点%下面语句也可获得零极点。[z,p,k]=tf2zp(num,den)pzmap(G1);%绘制零极点图gridon%打开绘图网络鼠标指向某零点或极点会显示该方框。极点、阻尼比ζ、超调量、固有频率wn.21nw-1.4-1.2-1-0.8-0.6-0.4-0.20-2.5-2-1.5-1-0.500.511.522.5Pole-ZeroMapRealAxisImaginaryAxiswnζwnζ由斜边和实部求出。超调量由ζ求出。21/eMpwnwnwn化传递函数为零极点形式num=[121];den=[15389];t=0.2;G2=tf(num,den,t)%有采样时间t，则显示为脉冲传递函数，自变量为zTransferfunction:z^2+2z+1-----------------------------，Samplingtime:0.2z^4+5z^3+3z^2+8z+9Transferfunction:z^2+2z+1-----------------------------z^4+5z^3+3z^2+8z+9Samplingtime:0.2G22=zpk(G2)%求离散系统G2零极点Zero/pole/gain:(z+1)^2----------------------------------------(z+4.635)(z+1)(z^2-0.6347z+1.942)Samplingtime:0.2num=[121];den=[15389];t=0.2;G1=tf(num,den)%没有采样时间t，则显示为传递函数,自变量为sTransferfunction:s^2+2s+1-----------------------------s^4+5s^3+3s^2+8s+9G11=zpk(G1)%求连续系统G1零极点Zero/pole/gain:(s+1)^2----------------------------------------(s+4.635)(s+1)(s^2-0.6347s+1.942)•num=[121];•den=[15389];•[z,p,k]=tf2zp(num,den)%化传递函数为零极点增益形式z=-1-1p=-4.63470.3174+1.3569i0.3174-1.3569i-1.0000k=1化零极点增益形式为传递函数[num1,den1]=zp2tf(z,p,k)%化零极点增益形式为传递函数num1=00121den1=1.00005.00003.00008.00009.0000系统的串、并联的传递函数•2s^2+6s+5•G1=---------------------•s^3+4s^2+5s+2•s^2+7s+12•G2=--------------•s^2+3s+2•分别求G1、G2串、并联后的传递函数。num2=[1712];den2=[132];G2=tf(num2,den2)；num1=[265];den1=[1452];G1=tf(num1,den1)；G=series(G1,G2)或G=G1*G2%串联Transferfunction:2s^4+20s^3+71s^2+107s+60----------------------------------------s^5+7s^4+19s^3+25s^2+16s+4Gp=parallel(G1,G2)或Gp=G1+G2%并联Transferfunction:s^5+13s^4+57s^3+112s^2+101s+34--------------------------------------------s^5+7s^4+19s^3+25s^2+16s+4用零阶保持器将连续系统离散化)]()([)(?)(1)()1(1)(sGsGZzGzGsesGsssGhsTh求零阶保持器：num=[1];den=conv([10],[11]);G=tf(num,den);G1=c2d(G,1,'zoh')%G1=c2d(sys,Ts,‘method’)Transferfunction:0.3679z+0.2642----------------------z^2-1.368z+0.3679Samplingtime:1连续转化为离散（系统，采样时间，’方法‘）