simple_pid.h

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/*
 * Copyright (c) 2017 Robert Leishman, BYU MAGICC Lab.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * * Redistributions of source code must retain the above copyright notice, this
 *   list of conditions and the following disclaimer.
 *
 * * Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 *
 * * Neither the name of the copyright holder nor the names of its
 *   contributors may be used to endorse or promote products derived from
 *   this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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#ifndef ROTOR_CONTROLLER_SIMPLE_PID_H
#define ROTOR_CONTROLLER_SIMPLE_PID_H

#include <ros/ros.h> // included temporarily for debug statements
#include <cmath>

namespace rosflight_utils
{
class SimplePID
{
public:
  SimplePID();

  SimplePID(double p, double i = 0.0, double d = 0.0, double max = DBL_MAX, double min = -DBL_MAX, double tau = 0.15);

  double computePID(double desired, double current, double dt, double x_dot = INFINITY);

  void setGains(double p, double i = 0.0, double d = 0.0, double tau = 0.15);

  void setLimits(double max, double min);

  void clearIntegrator() { integrator_ = 0.0; }

protected:
  double kp_;             
  double ki_;             
  double kd_;             
  double integrator_;     
  double differentiator_; 
  double last_error_;     
  double last_state_;     
  double tau_;            
  double max_;            
  double min_;            

  inline double saturate(double val, double &min, double &max)
  {
    if (val > max)
      val = max;
    else if (val < min)
      val = min;
    return val;
  }
};
} // namespace rosflight_utils

#endif // ROTOR_CONTROLLER_SIMPLE_PID_H