fig133.m

realize analysis and design for computer-controlled system

% Generates Fig 13.3 (identres)
% Using the System Identification Toolbox
% Computer Controlled Systems (3rd ed)
% Author: B. Wittenmark
% Last edit: 1997-08-04
% Copyright (c) 1996 by K. J. 舠tr鰉, B. Wittenmark and
% Department of Automatic Control, Lund Institute of
% Technology, Lund, Sweden

newplot;
set(gcf,'PaperUnits','centimeters','PaperPosition',[2 2 13 10])
set(gcf,'Units','centimeters','position',get(gcf,'PaperPosition'))

lw=0.9;

a1=-1.5;
a2=0.7;
b1=1;
b2=0.5;
c1=-1;
c2=0.2;
sig=0.5;

model=poly2th([1 a1 a2],[0 b1 b2],[1 c1 c2]);
u=idinput(600,'prbs',[0 1/6]);
u=-u(1:500);
randn('seed',0);
e=sig*randn(500,1);
y=idsim([u e],model);
ustep=ones(100,1);
ydet=idsim(ustep,model);
tdet=[1:100];
mydata=[y u];
arx111=arx(mydata,[1 1 1]);
y111=idsim(ustep,arx111);
subplot(3,2,1)
plot(tdet,y111,'k-',tdet,ydet,'k--','Linew',lw);
axis([0,100,0 10]);
set(gca,'Fontsize',9,'Fontname','NewCenturySchlbk');
set(gca,'xtick',[0 100],'ytick',[0 5 10]);
ylabel('Output','Fontsize',9,'Fontname','NewCenturySchlbk')
text(-28,10.3,'(a)','Fontsize',9,'Fontname','NewCenturySchlbk')

arx221=arx(mydata,[2 2 1]);
y221=idsim(ustep,arx221);
subplot(3,2,2)
plot(tdet,y221,'k-',tdet,ydet,'k--','Linew',lw);
axis([0,100,0 10]);
set(gca,'Fontsize',9,'Fontname','NewCenturySchlbk');
set(gca,'xtick',[0 100],'ytick',[0 5 10]);
ylabel('Output','Fontsize',9,'Fontname','NewCenturySchlbk')
text(-28,10.3,'(b)','Fontsize',9,'Fontname','NewCenturySchlbk')

arx441=arx(mydata,[4 4 1]);
y441=idsim(ustep,arx441);
subplot(3,2,3)
plot(tdet,y441,'k-',tdet,ydet,'k--','Linew',lw);
axis([0,100,0 10]);
set(gca,'Fontsize',9,'Fontname','NewCenturySchlbk');
set(gca,'xtick',[0 100],'ytick',[0 5 10]);
ylabel('Output','Fontsize',9,'Fontname','NewCenturySchlbk')
xlabel('Time','Fontsize',9,'Fontname','NewCenturySchlbk')
text(-28,10.3,'(c)','Fontsize',9,'Fontname','NewCenturySchlbk')

armx2221=armax(mydata,[2 2 2 1]);
ym2221=idsim(ustep,armx2221);
subplot(3,2,4)
plot(tdet,ym2221,'k-',tdet,ydet,'k--','Linew',lw);
axis([0,100,0 10]);
set(gca,'Fontsize',9,'Fontname','NewCenturySchlbk');
set(gca,'xtick',[0 100],'ytick',[0 5 10]);
ylabel('Output','Fontsize',9,'Fontname','NewCenturySchlbk')
xlabel('Time','Fontsize',9,'Fontname','NewCenturySchlbk')
text(-28,10.3,'(d)','Fontsize',9,'Fontname','NewCenturySchlbk')