fig115.m

来自「realize analysis and design for computer」· M 代码 · 共 59 行

% Generates Fig 11.5 (closedpoles)
% Computer Controlled Systems (3rd ed)
% Author: B. Wittenmark
% Last edit: 1997-07-10
% Copyright (c) 1996 by K. J. 舠tr鰉, B. Wittenmark and
% Department of Automatic Control, Lund Institute of
% Technology, Lund, Sweden

newplot;clf;
set(gcf,'PaperUnits','centimeters','PaperPosition',[2 2 13 9.5])
set(gcf,'Units','centimeters','position',get(gcf,'PaperPosition'))

lw=0.9;
den=[1 -4 6 -4 1];
num=0.25*[0 1 2 1 0];
K=[0.000001:0.0001:0.1,0.1:0.1:1,1.1:0.1:20,50,500,5000,50000,50000000];
[m,n]=size(K);
r=zeros(n,4);
for i=1:n,
  tot=num+K(i)*den;
  r(i,:)=roots(tot)';
  end;
ro4=sort(r');
ro2=ro4(1:2,:)';
plot(ro2,'k','Linew',lw);
hold on
plot(1,0,'mo','Linew',lw);
plot(-1,0,'mx','Linew',lw);
plot(0,0,'mx','Linew',lw);
t=0:.1:6.3;
plot(sin(t),cos(t),'k-','Linew',lw)
axis([-1.5,1.3,-1.1,1.1]);
axis('equal');
%title(['Fig 11.5']);
K=0.01563;
po(1,:)=roots(num+K*den)';
K=0.05;
po(2,:)=roots(num+K*den)';
K=0.5;
po(3,:)=roots(num+K*den)';
K=10;
po(4,:)=roots(num+K*den)';
po4=sort(po');
po2=po4(1:2,:)';
plot(po2,'k*','Linew',lw)
set(gca,'Fontsize',9,'Fontname','NewCenturySchlbk');
set(gca,'ytick',[-1 0 1]);
set(gca,'xtick',[-1 0 1]);
text(-0.32,0.1,'(a)','Fontsize',9,'Fontname','NewCenturySchlbk');
text(-0.15,0.35,'(b)','Fontsize',9,'Fontname','NewCenturySchlbk');
text(0.23,0.45,'(c)','Fontsize',9,'Fontname','NewCenturySchlbk');
text(0.58,0.37,'(d)','Fontsize',9,'Fontname','NewCenturySchlbk');
xlabel('Real axis','Fontsize',9,'Fontname','NewCenturySchlbk');
ylabel('Imaginary axis','Fontsize',9,'Fontname','NewCenturySchlbk');
plot([-3 3],[0 0],'k:','Linew',lw)
plot([0 0],[-2 2],'k:','Linew',lw)

hold off