% Generates Fig 4.21
% Computer Controlled Systems (3rd ed)
% Author: B. Wittenmark
% Last edit: 1997-07-02
% Copyright (c) 1996 by K. J. Åström, B. Wittenmark and
% Department of Automatic Control, Lund Institute of
% Technology, Lund, Sweden

close all; clear all;

%block421;

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

lw=2;
h=0.5;
sfbdesign
l1=L(1);
l2=L(2);
l3=L(3);
lc=l_c;
obsdesign
t0=0;
clf;

%
[t,x,y]=sim('block421',[0, 80]);
subplot(2,1,1);
plot(t,y(:,3),'k--',t,y(:,1),'b','Linew',lw);
axis([0,80,0,1.5]);
%title(['Fig 4.21']);
set(gca,'Fontsize',9,'Fontname','NewCenturySchlbk');
set(gca,'xtick',[0 20 40 60 80]);
set(gca,'ytick',[0 1]);
ylabel('Output','Fontname','NewCenturySchlbk','Fontsize',9)
title('u_c: a step at t = 0; v: a pulse of height: -10 & duration: 0.1 at t = 25')
drawnow;
%
subplot(2,1,2);
[ts,ys]=stairs(t,y(:,2));
plot(ts,ys,'r','Linew',lw);
axis([0,80,-1,2]);
set(gca,'Fontsize',9,'Fontname','NewCenturySchlbk');
set(gca,'xtick',[0 20 40 60 80]);
set(gca,'ytick',[-1 0 1 2]);
xlabel('Time','Fontname','NewCenturySchlbk','Fontsize',9)
ylabel('Input','Fontname','NewCenturySchlbk','Fontsize',9)
title('Use etimated states as state feedback')
drawnow;
%
ylblalgn;