pid.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

%升温
Close  all;
ts=1;
sys=tf(2.5,[1,50,0]);
dsys=c2d(sys,ts,'z');
[num,den]=tfdata(dsys,'v');
x=[0,0,0];
e=0;e_1=0;e_2=0;
u_1=0.0;u_2=0.0;u_3=0.0;
y_1=20;y_2=0;y_3=0;
for k =1:1:1000;
      time(k)=k*ts;
       rin(k)=38.0;
       kp=2;
       ki=0.015;
       kd=0.5;
       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=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)=e-e_1;
       x(2)=e-2*e_1+e_2;
       x(3)=e;
       e_2=e_1;
      e_1=e;  
end
  plot(time,rin,'b',time,yout,'r');
  xlabel('time(s)');ylabel('rin,yout');