PidController.cpp

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// Original version: Melonee Wise <mwise@willowgarage.com>
#include <cstdio>
#include "youbot_driver/generic/PidController.hpp"
#include <boost/math/special_functions/fpclassify.hpp>

namespace youbot {

PidController::PidController(double P, double I, double D, double I1, double I2) :
  p_gain_(P), i_gain_(I), d_gain_(D), i_max_(I1), i_min_(I2)
{
  p_error_last_ = 0.0;
  p_error_ = 0.0;
  d_error_ = 0.0;
  i_error_ = 0.0;
  cmd_ = 0.0;
  last_i_error = 0.0;
}

PidController::~PidController()
{
}

void PidController::initPid(double P, double I, double D, double I1, double I2)
{
  p_gain_ = P;
  i_gain_ = I;
  d_gain_ = D;
  i_max_ = I1;
  i_min_ = I2;

  reset();
}

void PidController::reset()
{
  p_error_last_ = 0.0;
  p_error_ = 0.0;
  d_error_ = 0.0;
  i_error_ = 0.0;
  cmd_ = 0.0;
}

void PidController::getGains(double &p, double &i, double &d, double &i_max, double &i_min)
{
  p = p_gain_;
  i = i_gain_;
  d = d_gain_;
  i_max = i_max_;
  i_min = i_min_;
}

void PidController::setGains(double P, double I, double D, double I1, double I2)
{
  p_gain_ = P;
  i_gain_ = I;
  d_gain_ = D;
  i_max_ = I1;
  i_min_ = I2;
}


double PidController::updatePid(double error, boost::posix_time::time_duration dt)
{
  double p_term, d_term, i_term;
  p_error_ = error; //this is pError = pState-pTarget
  double deltatime = (double)dt.total_microseconds()/1000.0; //in milli seconds
  

  if (deltatime == 0.0 || boost::math::isnan(error) || boost::math::isinf(error))
    return 0.0;

  // Calculate proportional contribution to command
  p_term = p_gain_ * p_error_;

  // Calculate the integral error
  
  i_error_ = last_i_error + deltatime * p_error_;
  last_i_error = deltatime * p_error_;

  //Calculate integral contribution to command
  i_term = i_gain_ * i_error_;

  // Limit i_term so that the limit is meaningful in the output
  if (i_term > i_max_)
  {
    i_term = i_max_;
    i_error_=i_term/i_gain_;
  }
  else if (i_term < i_min_)
  {
    i_term = i_min_;
    i_error_=i_term/i_gain_;
  }

  // Calculate the derivative error
  if (deltatime != 0)
  {
    d_error_ = (p_error_ - p_error_last_) / deltatime;
    p_error_last_ = p_error_;
  }
  // Calculate derivative contribution to command
  d_term = d_gain_ * d_error_;
  cmd_ = -p_term - i_term - d_term;
  
 // printf(" p_error_ %lf  i_error_ %lf  p_term %lf i_term %lf  dt %lf out %lf\n", p_error_, i_error_, p_term, i_term, deltatime, cmd_);

  return cmd_;
}


double PidController::updatePid(double error, double error_dot, boost::posix_time::time_duration dt)
{
  double p_term, d_term, i_term;
  p_error_ = error; //this is pError = pState-pTarget
  d_error_ = error_dot;
  double deltatime = (double)dt.total_microseconds()/1000.0;  //in milli seconds

  if (deltatime == 0.0 || boost::math::isnan(error) || boost::math::isinf(error) || boost::math::isnan(error_dot) || boost::math::isinf(error_dot))
    return 0.0;


  // Calculate proportional contribution to command
  p_term = p_gain_ * p_error_;

  // Calculate the integral error
  i_error_ = last_i_error + deltatime * p_error_;
  last_i_error = deltatime * p_error_;
  
 // i_error_ = i_error_ + deltatime * p_error_;
 //   printf("i_error_ %lf dt.fractional_seconds() %lf\n", i_error_, deltatime);

  //Calculate integral contribution to command
  i_term = i_gain_ * i_error_;

  // Limit i_term so that the limit is meaningful in the output
  if (i_term > i_max_)
  {
    i_term = i_max_;
    i_error_=i_term/i_gain_;
  }
  else if (i_term < i_min_)
  {
    i_term = i_min_;
    i_error_=i_term/i_gain_;
  }

  // Calculate derivative contribution to command
  d_term = d_gain_ * d_error_;
  cmd_ = -p_term - i_term - d_term;

  return cmd_;
}



void PidController::setCurrentCmd(double cmd)
{
  cmd_ = cmd;
}

double PidController::getCurrentCmd()
{
  return cmd_;
}

void PidController::getCurrentPIDErrors(double& pe, double& ie, double& de)
{
  pe = p_error_;
  ie = i_error_;
  de = d_error_;
}

}