pid2.txt

PID温度控制,实现温度升降,通过调节其中的Kp,Ki,Kd,可以改变响应速度,可以消除振荡,通过改变传递函数可以改变响应速度

%降温
close  all;
ts=1;
sys=tf(2.5,[1,50,0]);
dsys=c2d(sys,ts,'z');
[num,den]=tfdata(dsys,'v');
u_1=0.0;u_2=0.0;u_3=0.0;
y_1=38;y_2=0;y_3=0;
x=[0,0,0];
e=0;e_1=0;e_2=0;
for k =1:1:1000;
    time(k)=k*ts;
    rin(k)=0;
    kp=2;
    ki=0.01;
    kd=0.2;
    du(k)=kp*x(1)+kd*x(2)+ki*x(3);
    u(k)=u_1+du(k);
    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-num(2)*u_1-num(3)*u_2;
    e=yout(k)-rin(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)=e-e_1;
    x(2)=e-2*e_1+e_2;
    x(3)=e;
    e_2=e_1;
    e_1=e;
end
figure(2)
plot(time,rin,'b',time,yout,'r');
xlabel('time(s)');ylabel('rin,yout');
hold on