pid.m

基于MATLAB的PID程序

clear all;
close all;
ts=0.001;
sys=tf(5.235e005,[1,87.35,1.047e004,01]);
dsys=c2d(sys,ts,'z');
[num,den]=tfdata(dsys,'v');
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;
for k=1:1:500
    time(k)=k*ts;
    S=1;
    if S==1
        kp=0.50;
        ki=0.001;
        kd=0.001;
        rin(k)=1;
    elseif S==2
        kp=0.50;
        ki=0.001;
        kd=0.001;
        rin(k)=sign(sin(2*2*pi*k*ts));
    elseif S==3
        kp=1.5;
        ki=1.0;
        kd=0.01;
        rin(k)=0.5*sin(2*2*pi*k*ts);
    end
    u(k)=kp*x(1)+kd*x(2)+ki*x(3);
    if u(k)<=-10
        u(k)=-10;
    end
    if u(k)>=10
        u(k)=10;
    end
    yout(k)=-den(2)*y_1-den(3)*y_2-den(4)*y_3+num(2)*u_1+num(3)*u_2+num(4)*u_3;
    error(k)=rin(k)-yout(k);
    u_3=u_2;
    u_2=u_1;
    u_1=u(k);
    y_3=y_2;
    y_2=y_1;
    y_1=yout(k);
    x(1)=error(k);
    x(2)=(error(k)-error_1)/ts;
    x(3)=x(3)+error(k)*ts;
    error_1=error(k);
end
figure(1);
plot(time,rin,'b',time,yout,'r');
xlabel('time(s)');
ylabel('rin,yout');