Brewery/Arduino-PID-Library
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Merge 212d8fb4ab into d21d7e3d09

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bundgus 2013-02-21 20:08:47 -08:00
commit a2f02af7ce
2 changed files with 42 additions and 6 deletions
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41
PID_v1/PID_v1.cpp
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@ -21,6 +21,12 @@ PID::PID(double* Input, double* Output, double* Setpoint,
double Kp, double Ki, double Kd, int ControllerDirection)
{
priorInputsSum = 0.0;
priorInputCounter = 0;
for (int i = 0; i<5; i++){
priorInputs[i] = 0.0;
}
myOutput = Output;
myInput = Input;
mySetpoint = Setpoint;
@ -54,13 +60,33 @@ bool PID::Compute()
/*Compute all the working error variables*/
double input = *myInput;
double error = *mySetpoint - input;
ITerm+= (ki * error);
if (((kp * error)+ ITerm) < outMax){ // Modified Tracking Anti-Windup.. if proportional output is maxed, don't wind up the accumulator
ITerm+= (ki * error);}
if(ITerm > outMax) ITerm= outMax;
else if(ITerm < outMin) ITerm= outMin;
double dInput = (input - lastInput);
priorInputs[priorInputCounter] = input; // keep the last 5 input samples to be used for averaging for the differential multiplier Pd
if (priorInputCounter < 4){
priorInputCounter++;}
else{
priorInputCounter = 0;
}
double currentInputSum = 0.0;
for (int i = 0; i < 5; i++){
currentInputSum += priorInputs[i];
}
currentInputSum = currentInputSum / 5;
double dInput = (currentInputSum - priorInputsSum); // average of last 5 input samples minus average of last 2-6 input samples
//double dInput = (input - lastInput);
priorInputsSum = currentInputSum;
/*Compute PID Output*/
double output = kp * error + ITerm- kd * dInput;
double output = kp * error + ITerm - kd * dInput;
if(output > outMax) output = outMax;
else if(output < outMin) output = outMin;
@ -74,6 +100,13 @@ bool PID::Compute()
else return false;
}
/* ClearITerm() **********************************************************************
* Called to clear out the accumulator value, in the event of a significant tuning change
**********************************************************************************/
void PID::ClearITerm()
{
ITerm = 0;
}
/* SetTunings(...)*************************************************************
* This function allows the controller's dynamic performance to be adjusted.
@ -88,7 +121,7 @@ void PID::SetTunings(double Kp, double Ki, double Kd)
double SampleTimeInSec = ((double)SampleTime)/1000;
kp = Kp;
ki = Ki * SampleTimeInSec;
ki = Ki * SampleTimeInSec/100; // set the scale to allow reasonible Ki values > 1 for slow responding system
kd = Kd / SampleTimeInSec;
if(controllerDirection ==REVERSE)

7
PID_v1/PID_v1.h
View File

@ -41,7 +41,7 @@ class PID
// once it is set in the constructor.
void SetSampleTime(int); // * sets the frequency, in Milliseconds, with which
// the PID calculation is performed. default is 100
void ClearITerm(); // Called to clear out the accumulator value, in the event of a significant tuning change
//Display functions ****************************************************************
@ -71,7 +71,10 @@ class PID
unsigned long lastTime;
double ITerm, lastInput;
double priorInputs[5];
int priorInputCounter;
double priorInputsSum;
unsigned long SampleTime;
double outMin, outMax;
bool inAuto;