added library code files

Author: r-downing

AutoPID.cpp

@@ -0,0 +1,96 @@
+#include "AutoPID.h"
+
+AutoPID::AutoPID(double *input, double *setpoint, double *output, double outputMin, double outputMax,
+                 double Kp, double Ki, double Kd) {
+  _input = input;
+  _setpoint = setpoint;
+  _output = output;
+  _outputMin = outputMin;
+  _outputMax = outputMax;
+  setGains(Kp, Ki, Kd);
+  _timeStep = 1000;
+}//AutoPID::AutoPID
+
+void AutoPID::setGains(double Kp, double Ki, double Kd) {
+  _Kp = Kp;
+  _Ki = Ki;
+  _Kd = Kd;
+}//AutoPID::setControllerParams
+
+void AutoPID::setBangBang(double bangOn, double bangOff) {
+  _bangOn = bangOn;
+  _bangOff = bangOff;
+}//void AutoPID::setBangBang
+
+void AutoPID::setBangBang(double bangRange) {
+  setBangBang(bangRange, bangRange);
+}//void AutoPID::setBangBang
+
+void AutoPID::setOutputRange(double outputMin, double outputMax) {
+  _outputMin = outputMin;
+  _outputMax = outputMax;
+}//void AutoPID::setOutputRange
+
+void AutoPID::setTimeStep(unsigned long timeStep){
+  _timeStep = timeStep;
+}
+
+
+bool AutoPID::atSetPoint(double threshold) {
+  return abs(*_setpoint - *_input) <= threshold;
+}//bool AutoPID::atSetPoint
+
+void AutoPID::run() {
+  if (_stopped) {
+    _stopped = false;
+    reset();
+  }
+  //if bang thresholds are defined and we're outside of them, use bang-bang control
+  if (_bangOn && ((*_setpoint - *_input) > _bangOn)) {
+    *_output = _outputMax;
+    _lastStep = millis();
+  } else if (_bangOff && ((*_input - *_setpoint) > _bangOff)) {
+    *_output = _outputMin;
+    _lastStep = millis();
+  } else {                                    //otherwise use PID control
+    unsigned long _dT = millis() - _lastStep;   //calculate time since last update
+    if (_dT >= _timeStep) {                     //if long enough, do PID calculations
+      _lastStep = millis();
+      double _error = *_setpoint - *_input;
+      _integral += (_error + _previousError) / 2 * _dT / 1000.0;   //Riemann sum integral
+      //_integral = constrain(_integral, _outputMin/_Ki, _outputMax/_Ki);
+      double _dError = (_error - _previousError) / _dT / 1000.0;   //derivative
+      _previousError = _error;
+      double PID = (_Kp * _error) + (_Ki * _integral) + (_Kd * _dError);
+      //*_output = _outputMin + (constrain(PID, 0, 1) * (_outputMax - _outputMin));
+      *_output = constrain(PID, _outputMin, _outputMax);
+    }
+  }
+}//void AutoPID::run
+
+void AutoPID::stop() {
+  _stopped = true;
+  reset();
+}
+void AutoPID::reset() {
+  _lastStep = millis();
+  _integral = 0;
+  _previousError = 0;
+}
+
+bool AutoPID::isStopped(){
+  return _stopped;
+}
+
+void AutoPIDRelay::run() {
+  AutoPID::run();
+  while ((millis() - _lastPulseTime) > _pulseWidth) _lastPulseTime += _pulseWidth;
+  *_relayState = ((millis() - _lastPulseTime) < (_pulseValue * _pulseWidth));
+}
+
+
+double AutoPIDRelay::getPulseValue(){
+  return (isStopped()?0:_pulseValue);
+}
+
+

AutoPID.h

@@ -0,0 +1,61 @@
+#ifndef AUTOPID_H
+#define AUTOPID_H
+#include <Arduino.h>
+
+class AutoPID {
+
+  public:
+    // Constructor - takes pointer inputs for control variales, so they are updated automatically
+    AutoPID(double *input, double *setpoint, double *output, double outputMin, double outputMax,
+            double Kp, double Ki, double Kd);
+    // Allows manual adjustment of gains
+    void setGains(double Kp, double Ki, double Kd);
+    // Sets bang-bang control ranges, separate upper and lower offsets, zero for off
+    void setBangBang(double bangOn, double bangOff);
+    // Sets bang-bang control range +-single offset
+    void setBangBang(double bangRange);
+    // Allows manual readjustment of output range
+    void setOutputRange(double outputMin, double outputMax);
+    // Allows manual adjustment of time step (default 1000ms)
+    void setTimeStep(unsigned long timeStep);
+    // Returns true when at set point (+-threshold)
+    bool atSetPoint(double threshold);
+    // Runs PID calculations when needed. Should be called repeatedly in loop.
+    // Automatically reads input and sets output via pointers
+    void run();
+    // Stops PID functionality, output sets to 
+    void stop();
+    void reset();
+    bool isStopped();
+
+  private:
+    double _Kp, _Ki, _Kd;
+    double _integral, _previousError;
+    double _bangOn, _bangOff;
+    double *_input, *_setpoint, *_output;
+    double _outputMin, _outputMax;
+    unsigned long _timeStep, _lastStep;
+    bool _stopped;
+
+};//class AutoPID
+
+class AutoPIDRelay : public AutoPID {
+  public:
+
+    AutoPIDRelay(double *input, double *setpoint, bool *relayState, double pulseWidth, double Kp, double Ki, double Kd)
+      : AutoPID(input, setpoint, &_pulseValue, 0, 1.0, Kp, Ki, Kd) {
+      _relayState = relayState;
+      _pulseWidth = pulseWidth;
+    };
+
+    void run();
+
+    double getPulseValue();
+
+  private:
+    bool * _relayState;
+    unsigned long _pulseWidth, _lastPulseTime;
+    double _pulseValue;
+};//class AutoPIDRelay
+
+#endif