encoder with pid controller

i encounter following problems:
1)i need bit more precision. want count 1/2 ticks. got code here post 21. edit it, doesn't work leftencoderaset.
2)how can set value of ticks , goes in value.
3)how can find dead zone of dc motor , embed in code.

code: [select]


#include <digitalwritefast.h>
// quadrature encoders
// left encoder
#define c_leftencoderinterrupt 0
#define c_leftencoderpina 2
#define c_leftencoderinterrupt 1
#define c_leftencoderpinb 3
#define leftencoderisreversed
//
volatile bool _leftencoderaset;
volatile bool _leftencoderbset;

volatile long _leftencoderticks = 0;


//variables pid
double setpoint=1350.0;//h timi p thelw na paei
unsigned long lasttime;
double errsum, lasterr;
double input, output;
double kp=0.009;
double ki=0;
double kd=0;
int speedpin=5;
int motorpin1=6;
int motorpin2=7;

//send command 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(){
digitalwrite(motorpin1,low);
digitalwrite(motorpin2,high);
analogwrite(speedpin, abs(output));//abs apoliti t
}
void ccw(){
digitalwrite(motorpin1,high);
digitalwrite(motorpin2,low);
analogwrite(speedpin, abs(output));
}


//compute controller output pid algorithm

void compute()
{
   /*how long since last calculated*/
   unsigned long = millis();
   double timechange = (double)(now - lasttime);
  input=_leftencoderticks;
   /*compute 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)+60);
 
   
if(output>255){output = 255;}
else if(output <-255){output = -255;}
else{}
 
   /*remember variables next time*/
   lasterr = error;
   lasttime = now;
}

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

// quadrature encoders
// left encoder
pinmode(c_leftencoderpina, input); // sets pin input
digitalwrite(c_leftencoderpina, low); // turn on pullup resistors
pinmode(c_leftencoderpinb, input); // sets pin b input
digitalwrite(c_leftencoderpinb, low); // turn on pullup resistors
_leftencoderaset = digitalreadfast(c_leftencoderpina);   // read input pin
_leftencoderbset = digitalreadfast(c_leftencoderpinb);   // read input pin
attachinterrupt(c_leftencoderinterrupt, handleleftmotorinterrupta, rising);
attachinterrupt(c_leftencoderinterrupt, handleleftmotorinterruptb, rising);
pinmode(motorpin1, output);
pinmode(motorpin2, output);
pinmode(speedpin, output);

// left encoder
pinmode(c_leftencoderpina, input); // sets pin input
digitalwrite(c_leftencoderpina, high); // turn on pullup resistors
pinmode(c_leftencoderpinb, input); // sets pin b input
digitalwrite(c_leftencoderpinb, high); // turn on pullup resistors
_leftencoderaset = digitalreadfast(c_leftencoderpina);   // read input pin
_leftencoderbset = digitalreadfast(c_leftencoderpinb);   // read input pin
attachinterrupt(c_leftencoderinterrupt, handleleftmotorinterrupta, falling);
attachinterrupt(c_leftencoderinterrupt, handleleftmotorinterruptb, falling);
pinmode(motorpin1, output);
pinmode(motorpin2, output);
pinmode(speedpin, output);
}


// interrupt service routines left motor's quadrature encoder
void handleleftmotorinterrupta()
{
// test transition
  _leftencoderaset = digitalreadfast(c_leftencoderpina);   // read input pin
  _leftencoderbset = digitalreadfast(c_leftencoderpinb);   // read input pin

  // , adjust counter + if leads b
#ifdef leftencoderisreversed
_leftencoderticks += (_leftencoderaset != _leftencoderbset) ? -1 : +1;
#else
_leftencoderticks -= (_leftencoderaset != _leftencoderbset) ? -1 : +1;
#endif
}
// interrupt service routines left motor's quadrature encoder
void handleleftmotorinterruptb()
{
// test transition
  _leftencoderaset = digitalreadfast(c_leftencoderpina);   // read input pin
  _leftencoderbset = digitalreadfast(c_leftencoderpinb);   // read input pin

  // , adjust counter + if leads b
#ifdef leftencoderisreversed
_leftencoderticks += (_leftencoderaset != _leftencoderbset) ? -1 : +1;
#else
_leftencoderticks -= (_leftencoderaset != _leftencoderbset) ? -1 : +1;
#endif
}


quote from: kostas15 on jun 22, 2013, 10:05 pm

2)how can set value of ticks , goes in value.
3)how can find dead zone of dc motor , embed in code.

sorry, don't understand question.

perhaps consider encoder value number of half-ticks, semi-ticks etc. still dealing integer value.

if want drive motor until encoder position reaches specified value method of doing semi-ticks same ticks - integer value less than, more or equal target position.

what mean dead zone?

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