ex9_1.m

离散控制系统设计的MATLAB 代码

%%%%%%%%%%%%%%%%%% Example 9.1 %%%%%%%%%%%%%%%%%%
%   Discrete-Time Control Problems using        %
%       MATLAB and the Control System Toolbox   %
%   by J.H. Chow, D.K. Frederick, & N.W. Chbat  %
%         Brooks/Cole Publishing Company        %
%                September 2002                 %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%   ---- Frequency-response plots of G(z) and G(w) ----
%
clear
disp('Example 9.1')

num = 4                             % numerator
den = conv([2 1],[0.5 1])           % denominator
Gp = tf(num,den)        % continuous lti object
Ts = 0.1                % sampling time
Gz = c2d(Gp,Ts,'zoh')   % discretization
Gw = d2c(Gz,'tustin')   % bilinear transform
disp('******>'), pause

figure, bode(Gz),grid
title('Frequency response of G(z)')
disp('Click on the frequency response curves to find')
disp('frequency response values')
disp('******>'), pause
figure, bode(Gw,logspace(-1,4,100)),grid
title('Frequency response of G(w)')
disp('Click on the frequency response curves to find')
disp('frequency response values')
disp('******>'), pause
w = 5*pi
ww = 2/Ts*tan(w*Ts/2)
[magz,phz] = bode(Gz,w)    % find magnitude and 
[magw,phw] = bode(Gw,ww)   % ... phase
%%%%%%%%%%