fig113.m

realize analysis and design for computer-controlled system

% Generates Fig 11.3 (ldouble)
% 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;
clear;
set(gcf,'PaperUnits','centimeters','PaperPosition',[2 2 13 10])
set(gcf,'Units','centimeters','position',get(gcf,'PaperPosition'))
lw=0.9;
N=100;
h=1;
Ac=[0 1;0 0];
Bc=[0;1];
[A,B]=c2d(Ac,Bc,h);
Q=[1 0;0 0];
R=logspace(-5,5,N);
L=zeros(N,2);
E=zeros(N,2);
S=zeros(N,3);
for k=1:N,
[L1,S1,E1]=dlqr(A,B,Q,R(k)); 
L(k,:)=L1;
E(k,:)=E1';
S(k,1)=S1(1,1);
S(k,2)=S1(1,2);
S(k,3)=S1(2,2);
end;

subplot(3,1,1)
semilogx(R,L(:,1),'k-',R,L(:,2),'k--','Linewi',lw)
axis([0.00001 100000 0 2])
set(gca,'Fontsize',9,'Fontname','NewCenturySchlbk');
set(gca,'ytick',[0 2]);
xlabel('Control weighting \rho','Fontname','NewCenturySchlbk','Fontsize',9)
ylabel(' Gains {\it l_i}','Fontname','NewCenturySchlbk','Fontsize',9)