optical encoder with pid controller

Projects Programming
1

GOOD EVENING YOUI HAVE A PROBLEM WITH THE PID CONTROLLER I CAN NOT FIND THE RIGHT Kp Ki Kd WHETHER TO GO TO SETPOINT I'VE argument. COULD SOMEONE TO HELP ME?

[#include <digitalWriteFast.h>
 // Quadrature encoders
// Left encoder
#define c_LeftEncoderInterruptA 0
#define c_LeftEncoderPinA 2
#define c_LeftEncoderInterruptB 1
#define c_LeftEncoderPinB 3
#define LeftEncoderIsReversed

volatile bool _LeftEncoderASet;
volatile bool _LeftEncoderBSet;

volatile long _LeftEncoderTicks = 0;


//Variables for PID
double Setpoint=10800.0;
unsigned long lastTime;
double errSum, lastErr;
double Input, Output;
double kp=0.1;
double ki=0;
double kd=0;
int SpeedPin=5;
int motorPin1=6;
int motorPin2=7;

//Send command to DC motor
void loop(){
 


Input=_LeftEncoderTicks;
Compute();
if(Output > 0) {
CC();
}
else if(Output<=0){
CCW();
}
Serial.print(_LeftEncoderTicks);
Serial.print("\n");

delay(20);
}

//Motor Control Function
void CC(){
digitalWriteFast(motorPin1,LOW);
digitalWriteFast(motorPin2,HIGH);
analogWrite(SpeedPin, abs(Output));
}
void CCW(){
digitalWriteFast(motorPin1,HIGH);
digitalWriteFast(motorPin2,LOW);
analogWrite(SpeedPin, abs(Output));
}

//Compute controller output by PID algorithm

void Compute()
{
   /*How long since we last calculated*/
   unsigned long now = millis();
   double timeChange = (double)(now - lastTime);
  Input=_LeftEncoderTicks;
   /*Compute all the working error variables*/
   double error = Setpoint - Input;
   errSum += (error * timeChange);
   double dErr = (error - lastErr) / timeChange;
  
   /*Compute PID Output*/
   Output = (kp * error + ki * errSum + kd * dErr)+80;
  
   
 if(Output>255){Output = 255;}
else if(Output <-255){Output = -255;}
else{}
  
   /*Remember some variables for next time*/
   lastErr = error;
   lastTime = now;
}

void setup()
{
Serial.begin(115200);

// Quadrature encoders
// Left encoder
pinMode(c_LeftEncoderPinA, INPUT); // sets pin A as input
pinMode(c_LeftEncoderPinB, INPUT); // sets pin B as input
_LeftEncoderASet = digitalReadFast(c_LeftEncoderPinA);   // read the input pin
_LeftEncoderBSet = digitalReadFast(c_LeftEncoderPinB);   // read the input pin
attachInterrupt(c_LeftEncoderInterruptA, HandleLeftMotorInterruptA, CHANGE);
attachInterrupt(c_LeftEncoderInterruptB, HandleLeftMotorInterruptB, CHANGE);
pinMode(motorPin1, OUTPUT);
pinMode(motorPin1, OUTPUT);
pinMode(motorPin2, OUTPUT);
pinMode(SpeedPin, OUTPUT);
}
// Interrupt service routines for the left motor’s quadrature encoder
void HandleLeftMotorInterruptA()
{
// Test transition
  _LeftEncoderASet = digitalReadFast(c_LeftEncoderPinA);   // read the input pin
  _LeftEncoderBSet = digitalReadFast(c_LeftEncoderPinB);   // read the input pin

 if(_LeftEncoderASet != _LeftEncoderBSet) {
   _LeftEncoderTicks=_LeftEncoderTicks + 1;
 }
   else {
     _LeftEncoderTicks=_LeftEncoderTicks - 1;
   }  
}
// Interrupt service routines for the left motor’s quadrature encoder
void HandleLeftMotorInterruptB()
{
// Test transition
  _LeftEncoderASet = digitalReadFast(c_LeftEncoderPinA);   // read the input pin
  _LeftEncoderBSet = digitalReadFast(c_LeftEncoderPinB);   // read the input pin

  // and adjust counter + if A leads B
 if ( _LeftEncoderASet == _LeftEncoderBSet) {
   _LeftEncoderTicks=_LeftEncoderTicks + 1;
 }
  else {
    _LeftEncoderTicks=_LeftEncoderTicks - 1;
  }
}]
2

You need to understand how the PID algorithm works, understand how to apply that to your problem, implement the PID controller, understand how to tune a PID controller and then tune your PID controller.

Which of these have you accomplished so far?

(If you could STOP SHOUTING that would be appreciated, too.)

3

Thanks for the help. I have not been able to find anything, could you send me some websites to understand how it works the Pid controller.So far I tried random.

4

could you send me some websites to understand how it works the Pid controller.

How WHAT works with the PID controller? Only YOU know what IT is.

5

Have a look at Improving the Beginner’s PID – Introduction « Project Blog and the pages that it links to