bode1.m

控制系统仿真中的频率特性的MATLAB源码

%绘制开环bode图

disp('开环传递函数G(s)为：')
printsys(num1,den1,'s');
disp('反馈传递函数H(s)为:')
printsys(num2,den2,'s');
lcwin=figure('Position',[120 49 513 491],'Name','开环bode图','NumberTitle','off',...
      'MenuBar','none');

axes('position',[0 0 1 1]);
axis off;

htext1=uicontrol(lcwin,'style','text','units','normalized','position',[0.03 0.15 0.22 0.08],...
        'fontsize',15,'back',[1 1 1]);
htext2=uicontrol(lcwin,'style','text','units','normalized','position',[0.53 0.15 0.22 0.08],...
        'fontsize',15,'back',[1 1 1]);    
htext3=uicontrol(lcwin,'style','text','units','normalized','position',[0.03 0.03 0.22 0.10],...
        'fontsize',15,'back',[1 1 1]); 
    htext4=uicontrol(lcwin,'style','text','units','normalized','position',[0.53 0.03 0.22 0.10],...
        'fontsize',15,'back',[1 1 1]); 

%设置编辑文本框
numedit1=uicontrol(lcwin,'style','edit','units','normalized','position',[0.25 0.15 0.15 0.08],...
        'fontsize',15,'back',[1 1 1]);
numedit2=uicontrol(lcwin,'style','edit','units','normalized','position',[0.75 0.15 0.15 0.08],...
        'fontsize',15,'back',[1 1 1]);
    numedit3=uicontrol(lcwin,'style','edit','units','normalized','position',[0.25 0.05 0.15 0.08],...
        'fontsize',15,'back',[1 1 1]);
    
    numedit4=uicontrol(lcwin,'style','edit','units','normalized','position',[0.75 0.05 0.15 0.08],...
        'fontsize',15,'back',[1 1 1]);
%设置绘图区域
axes('Position',[.15 .33 .8 .56]);


%绘制开环bode图
n1=poly2sym(num1)
n2=poly2sym(num2)
d1=poly2sym(den1)
d2=poly2sym(den2)
num3=sym2poly(n1*n2)
den3=sym2poly(d1*d2)

  w=logspace(-1,2)
    [m,p]=bode(num3,den3,w)
    subplot('position',[0.25,0.68,0.55,0.25])
    semilogx(w,20*log10(m))
title('开环bode图')
    ylabel('幅值') 
    grid on
    subplot('position',[0.25,0.35,0.55,0.25])
    semilogx(w,p)
    xlabel('频率')
    ylabel('相角')
    grid on

sys3=tf(num3,den3)
  [Gm,Pm,Wcg,Wcp]=margin(sys3)

  set(numedit1,'string',Gm)
  set(numedit2,'string',Pm)
  set(numedit3,'string',Wcg)
  set(numedit4,'string',Wcp)
set(htext1,'string','幅值裕度Gm')
set(htext2,'string','相角裕度Pm')
set(htext3,'string','-pi穿越频率Wcg')
set(htext4,'string','剪切频率Wcp')