electrical.c

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/*
 * Copyright (C) 2010-2013 The Paparazzi Team
 *
 * This file is part of paparazzi.
 *
 * paparazzi is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * paparazzi is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with paparazzi; see the file COPYING.  If not, write to
 * the Free Software Foundation, 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include "subsystems/electrical.h"

#include "mcu_periph/adc.h"
#include "subsystems/commands.h"

#include "autopilot.h"

#include "generated/airframe.h"
#include BOARD_CONFIG

#ifdef MILLIAMP_PER_PERCENT
#warning "deprecated MILLIAMP_PER_PERCENT --> Please use MILLIAMP_AT_FULL_THROTTLE"
#endif
#if defined BATTERY_SENS || defined BATTERY_OFFSET
#warning "BATTERY_SENS and BATTERY_OFFSET are deprecated, please remove them --> if you want to change the default use VoltageOfAdc"
#endif

#if defined COMMAND_THROTTLE
#define COMMAND_CURRENT_ESTIMATION COMMAND_THROTTLE
#elif defined COMMAND_THRUST
#define COMMAND_CURRENT_ESTIMATION COMMAND_THRUST
#endif

#ifndef BAT_CHECKER_DELAY
#define BAT_CHECKER_DELAY 5
#endif

#define ELECTRICAL_PERIODIC_FREQ 10
static float period_to_hour = 1 / 3600.f / ELECTRICAL_PERIODIC_FREQ;

#ifndef MIN_BAT_LEVEL
#define MIN_BAT_LEVEL 3
#endif

PRINT_CONFIG_VAR(LOW_BAT_LEVEL)
PRINT_CONFIG_VAR(CRITIC_BAT_LEVEL)
PRINT_CONFIG_VAR(MIN_BAT_LEVEL)

struct Electrical electrical;

#if defined ADC_CHANNEL_VSUPPLY || (defined ADC_CHANNEL_CURRENT && !defined SITL) || defined MILLIAMP_AT_FULL_THROTTLE
static struct {
#ifdef ADC_CHANNEL_VSUPPLY
  struct adc_buf vsupply_adc_buf;
#endif
#if defined ADC_CHANNEL_CURRENT && !defined SITL
  struct adc_buf current_adc_buf;
#endif
#ifdef MILLIAMP_AT_FULL_THROTTLE
  float nonlin_factor;
#endif
} electrical_priv;
#endif

#ifndef VoltageOfAdc
#define VoltageOfAdc(adc) DefaultVoltageOfAdc(adc)
#endif
#ifndef MilliAmpereOfAdc
#define MilliAmpereOfAdc(adc) DefaultMilliAmpereOfAdc(adc)
#endif

#ifndef CURRENT_ESTIMATION_NONLINEARITY
#define CURRENT_ESTIMATION_NONLINEARITY 1.2
#endif

#if defined MILLIAMP_AT_FULL_THROTTLE && !defined MILLIAMP_AT_IDLE_THROTTLE
  PRINT_CONFIG_MSG("Assuming 0 mA at idle throttle")
  #define MILLIAMP_AT_IDLE_THROTTLE 0
#endif

PRINT_CONFIG_VAR(MILLIAMP_AT_IDLE_THROTTLE)

void electrical_init(void)
{
  electrical.vsupply = 0.f;
  electrical.current = 0.f;
  electrical.charge  = 0.f;
  electrical.energy  = 0.f;

  electrical.bat_low = false;
  electrical.bat_critical = false;

#if defined ADC_CHANNEL_VSUPPLY
  adc_buf_channel(ADC_CHANNEL_VSUPPLY, &electrical_priv.vsupply_adc_buf, DEFAULT_AV_NB_SAMPLE);
#endif

  /* measure current if available, otherwise estimate it */
#if defined ADC_CHANNEL_CURRENT && !defined SITL
  adc_buf_channel(ADC_CHANNEL_CURRENT, &electrical_priv.current_adc_buf, DEFAULT_AV_NB_SAMPLE);
#elif defined MILLIAMP_AT_FULL_THROTTLE
  PRINT_CONFIG_VAR(CURRENT_ESTIMATION_NONLINEARITY)
  electrical_priv.nonlin_factor = CURRENT_ESTIMATION_NONLINEARITY;
#endif
}

void electrical_periodic(void)
{
  static uint32_t bat_low_counter = 0;
  static uint32_t bat_critical_counter = 0;
  static bool vsupply_check_started = false;

#if defined(ADC_CHANNEL_VSUPPLY) && !defined(SITL) && !USE_BATTERY_MONITOR
  electrical.vsupply = VoltageOfAdc((electrical_priv.vsupply_adc_buf.sum /
                                          electrical_priv.vsupply_adc_buf.av_nb_sample));
#endif

#ifdef ADC_CHANNEL_CURRENT
#ifndef SITL
  int32_t current_adc = electrical_priv.current_adc_buf.sum / electrical_priv.current_adc_buf.av_nb_sample;
  electrical.current = MilliAmpereOfAdc(current_adc) / 1000.f;
#endif
#elif defined MILLIAMP_AT_FULL_THROTTLE && defined COMMAND_CURRENT_ESTIMATION
  /*
   * Superellipse: abs(x/a)^n + abs(y/b)^n = 1
   * with a = 1
   * b = mA at full throttle
   * n = 1.2     This defines nonlinearity (1 = linear)
   * x = throttle
   * y = current
   *
   * define CURRENT_ESTIMATION_NONLINEARITY in your airframe file to change the default nonlinearity factor of 1.2
   */
  static float full_current = (float)MILLIAMP_AT_FULL_THROTTLE / 1000.f;
  static float idle_current = (float)MILLIAMP_AT_IDLE_THROTTLE / 1000.f;

  float x = ((float)commands[COMMAND_CURRENT_ESTIMATION]) / ((float)MAX_PPRZ);

  /* Boundary check for x to prevent math errors due to negative numbers in
   * pow() */
  Bound(x, 0.f, 1.f);

  /* electrical.current y = ( b^n - (b* x/a)^n )^1/n
   * a=1, n = electrical_priv.nonlin_factor
   */
#ifndef FBW
  if(autopilot_throttle_killed()) {
    // Assume no current when throttle killed (motors off)
    electrical.current = 0;
  } else {
#endif
    electrical.current = full_current -
                         powf((powf(full_current - idle_current, electrical_priv.nonlin_factor) -
                              powf(((full_current - idle_current) * x), electrical_priv.nonlin_factor)),
                           (1.f / electrical_priv.nonlin_factor));
#ifndef FBW
  }
#endif
#endif /* ADC_CHANNEL_CURRENT */

  float consumed_since_last = electrical.current * period_to_hour;

  electrical.charge += consumed_since_last;
  electrical.energy += consumed_since_last * electrical.vsupply;

  /*if valid voltage is seen then start checking. Set min level to 0 to always start*/
  if (electrical.vsupply >= MIN_BAT_LEVEL) {
    vsupply_check_started = true;
  }

  if (vsupply_check_started) {
    if (electrical.vsupply < LOW_BAT_LEVEL) {
      if (bat_low_counter > 0) {
        bat_low_counter--;
      }
      if (bat_low_counter == 0) {
        electrical.bat_low = true;
      }
    } else {
      // reset battery low status and counter
      bat_low_counter = BAT_CHECKER_DELAY * ELECTRICAL_PERIODIC_FREQ;
      electrical.bat_low = false;
    }

    if (electrical.vsupply < CRITIC_BAT_LEVEL) {
      if (bat_critical_counter > 0) {
        bat_critical_counter--;
      }
      if (bat_critical_counter == 0) {
        electrical.bat_critical = true;
      }
    } else {
      // reset battery critical status and counter
      bat_critical_counter = BAT_CHECKER_DELAY * ELECTRICAL_PERIODIC_FREQ;
      electrical.bat_critical = false;
    }
  }

}