matlab_pid.rar_pid整定_增量PID

%//==========================================================// %ljk,revised 2010-7-4 wuxi pid %Matlab仿真程序如下： %// %==========================================================// close all;clc;clear; ts=0.001; %sampling periods of system// %===================================// sys=tf(200,[1,40,0]); % 200 % ---------- % s^2 + 40 s %==================================// dsys=c2d(sys,ts,'z'); %Transfer function: % 9.868e-005 z + 9.737e-005 %------------------------- % z^2 - 1.961 z + 0.9608 % Sampling time: 0.001 %=================================// [num,den]=tfdata(dsys,'v'); %num:1.0e-004 * 0 0.9868 0.9737 %den: 1.0000 -1.9608 0.9608 u_1=0.0;u_2=0.0;u_3=0.0; y_1=0.0;y_2=0.0;y_3=0.0; x=[0,0,0]'; error_1=0; % error_2=0; % for k=1:1:1000; time(k)=k*ts; rin(k)=1.0; % reference input for PID ontrollor// kp=5; % ki=0.10; kd=10; %// %//du(k)=kp[e(k)-e(k-1)]+ki*e(k)+... %//kd*(e(k)-2e(k-1)+e(k-2)) %// du(k)=kp*x(1)+kd*x(2)+ki*x(3); u(k)=u_1+du(k); %//u(k)=u(k-1)+du(k) %// %=========================// if (u(k)>10) u(k)=10; end; if (u(k)<-10) u(k)=-10; end; %==========================// %//y(n)=1.961y(n-1)-0.9608y(n-2)+9.868x(n-1) %//+9.737x(n-2); yout(k)=-den(2)*y_1-den(3)*y_2+num(2)*u_1+num(3)*u_2; error=rin(k)-yout(k); %caculat the current error PID// u_3=u_2; u_2=u_1; u_1=u(k); %//u_1 save the last control varible % y_3=y_2; y_2=y_1; y_1=yout(k); x(1)=error-error_1; %//x(1)=e(k)-e(k-1)// %//x(2)=e(k)-2e(k-1)+e(k-2) x(2)=error-2*error_1+error_2; x(3)=error; %//x(3)=e(k); %// error_2=error_1; error_1=error; end; %//==============================================================// plot(time,rin,'b',time,yout,'r'); %//plot reference value & pid result./////// xlabel('time(s)');ylabel('rin,yout'); %//=============================================================//