ex2_10.m

离散控制系统设计的MATLAB 代码

%%%%%%%%%%%%%%%%% Example 2.10 %%%%%%%%%%%%%%%%%%
%   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                 %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%   ---- Blocking zeros ----
%
clear
disp('Example 2.10')
zz = [-0.3; exp(0.5i); exp(-0.5i)];   % zeros of G(z)
pp = [0.9; 0.7; 0.7; -0.5];           % poles of G(z)
gn = 1, Ts = 1                        % unity gain & sampling period
G = zpk(zz,pp,gn,Ts)                  % build G(z) as ZPK object
figure
ucircle, axis equal, hold on          % set up unit circle
pzmap(G), hold off                    % plot poles & zeros
set_xo_size                           % show larger X's and O's
disp('Plotting pole-zero locations')
disp('******>'), pause 

%--- zeros determined as roots of numerator polynomial ----
[numG,denG] = tfdata(G,'v')           % zeros determined as roots     
%--- magnitudes and angles of zeros from tfdata command ---
disp('Zeros of G via roots command')
xy2p(roots(numG));                    % ...of numerator polynomial
%--- magnitudes and angles of zeros from tzero command ---
disp('Zeros of G via tzero command')
xy2p(tzero(G));                       % zeros determined by 'tzero' command

k  = [0:50];                          % generate discrete time array
u  = sin(0.5*k);                      % generate discrete input sequence signal
[ylsim,k] = lsim(G,u);                % compute system response due to u(k)

figure
stem(k,ylsim,'filled'),grid           % plot response
hold on 
plot(k,u,'o'), hold off               % plot sinusoidal input
text(31,0.8,'input')
text(16,1.9,'output')
title('Example 2.10')
xlabel('Discrete time (k)')
%%%%%%%%%%