www.pudn.com > chap1.rar > chap1_8s.m

function [sys,x0,str,ts]=exp_pidf(t,x,u,flag) 
switch flag, 
case 0           % initializations 
    [sys,x0,str,ts] = mdlInitializeSizes; 
case 2           % discrete states updates 
    sys = mdlUpdates(x,u); 
case 3           % computation of control signal 
%    sys = mdlOutputs(t,x,u,kp,ki,kd,MTab); 
    sys=mdlOutputs(t,x,u); 
case {1, 4, 9}   % unused flag values 
    sys = []; 
otherwise        % error handling 
    error(['Unhandled flag = ',num2str(flag)]); 
end; 
 
%============================================================== 
% when flag=0, perform system initialization 
%============================================================== 
function [sys,x0,str,ts] = mdlInitializeSizes 
sizes = simsizes;        % read default control variables 
sizes.NumContStates = 0; % no continuous states 
sizes.NumDiscStates = 3; % 3 states and assume they are the P/I/D components 
sizes.NumOutputs = 1;    % 2 output variables: control u(t) and state x(3) 
sizes.NumInputs = 2;     % 4 input signals 
sizes.DirFeedthrough = 1;% input reflected directly in output 
sizes.NumSampleTimes = 1;% single sampling period 
sys = simsizes(sizes);   %  
x0 = [0; 0; 0];          % zero initial states 
str = [];  
ts = [-1 0];             % sampling period 
%============================================================== 
% when flag=2, updates the discrete states 
%============================================================== 
function sys = mdlUpdates(x,u) 
T=0.001; 
sys=[ u(1);  
      x(2)+u(1)*T; 
      (u(1)-u(2))/T]; 
 
%============================================================== 
% when flag=3, computates the output signals 
%============================================================== 
function sys = mdlOutputs(t,x,u,kp,ki,kd,MTab) 
 
kp=1.5; 
ki=2.0; 
kd=0.05; 
 
%sys=[kp,ki,kd]*x; 
sys=kp*x(1)+ki*x(2)+kd*x(3);