PID implementation using code

조회 수: 7(최근 30일)
Sanjeet Kulkarni
Sanjeet Kulkarni 2022년 11월 24일
댓글: Sanjeet Kulkarni 2022년 11월 28일
I have implemented a PID controller using simulink pid block for a system. I was trying to implement the same thing using a PID code (formula) in a matlab function block and compare the performances. However, I am getting differences in both the cases. Unable to figure out where exactly is the problem.
For simulink block I have implemented antiwindup, similarly I have done it in the code.
PID code as in the matlab function is as below:
function y = fcn(error,kp,ki)
dt = sampletime;
persistent integral newintegral
if isempty(integral)
integral = 0;
if isempty(newintegral)
newintegral = 0;
newintegral = integral + (error*dt);
output = kp*error + ki * integral;
if output>48000
elseif output<3000
output =3000;
integral = newintegral;
y = output;
Is there anything that I am implementing wrong in the code? Requesting some help/direction.
Thank you


Sam Chak
Sam Chak 2022년 11월 25일
Wouldn't it be simpler if you obtain the signal directly from the Integrator block, and then feed it into the MATLAB function block? Something like this
function y = fcn(err, errint, Kp, Ki)
where err is the error signal and errint is the intergral of error signal.
  댓글 수: 3
Sanjeet Kulkarni
Sanjeet Kulkarni 2022년 11월 28일
I have used the clamp method of antiwindup, where in the integral action should be clamped to the maximum and mininum limits of the actuator.
Have declared integral as a persistent variable (not the built in function).

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