/**
******************************************************************************
* @addtogroup OpenPilotModules OpenPilot Modules
* @{
* @addtogroup BatteryModule Battery Module
* @brief Measures battery voltage and current
* Updates the FlightBatteryState object
* @{
*
* @file battery.c
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* @brief Module to read the battery Voltage and Current periodically and set alarms appropriately.
*
* @see The GNU Public License (GPL) Version 3
*
*****************************************************************************/
/*
* This program 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 3 of the License, or
* (at your option) any later version.
*
* This program 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 this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/**
* Output object: FlightBatteryState
*
* This module will periodically generate information on the battery state.
*
* UAVObjects are automatically generated by the UAVObjectGenerator from
* the object definition XML file.
*
* Modules have no API, all communication to other modules is done through UAVObjects.
* However modules may use the API exposed by shared libraries.
* See the OpenPilot wiki for more details.
* http://www.openpilot.org/OpenPilot_Application_Architecture
*
*/
#include "openpilot.h"
#include "flightstatus.h"
#include "flightbatterystate.h"
#include "flightbatterysettings.h"
#include "hwsettings.h"
//
// Configuration
//
#define SAMPLE_PERIOD_MS 500
// Private types
// Private variables
static bool batteryEnabled = false;
// THESE COULD BE BETTER AS SOME KIND OF UNION OR STRUCT, BY WHICH 4 BITS ARE USED FOR EACH
// PIN VARIABLE, ONE OF WHICH INDICATES SIGN, AND THE OTHER 3 BITS INDICATE POSITION. THIS WILL
// WORK FOR QUITE SOMETIME, UNTIL MORE THAN 8 ADC ARE AVAILABLE. EVEN AT THIS POINT, THE STRUCTURE
// CAN SIMPLY BE MODIFIED TO SUPPORT 15 ADC PINS, BY USING ALL AVAILABLE BITS.
static int8_t voltageADCPin = -1; // ADC pin for voltage
static int8_t currentADCPin = -1; // ADC pin for current
// Private functions
static void onTimer(UAVObjEvent *ev);
static int8_t GetNbCells(const FlightBatterySettingsData *batterySettings, FlightBatteryStateData *flightBatteryData);
/**
* Initialise the module, called on startup
* \returns 0 on success or -1 if initialisation failed
*/
int32_t BatteryInitialize(void)
{
#ifdef MODULE_BATTERY_BUILTIN
batteryEnabled = true;
#else
uint8_t optionalModules[HWSETTINGS_OPTIONALMODULES_NUMELEM];
HwSettingsOptionalModulesGet(optionalModules);
if ((optionalModules[HWSETTINGS_OPTIONALMODULES_BATTERY] == HWSETTINGS_OPTIONALMODULES_ENABLED)) {
batteryEnabled = true;
} else {
batteryEnabled = false;
}
#endif
uint8_t adcRouting[HWSETTINGS_ADCROUTING_NUMELEM];
HwSettingsADCRoutingArrayGet(adcRouting);
// Determine if the battery sensors are routed to ADC pins
for (int i = 0; i < HWSETTINGS_ADCROUTING_NUMELEM; i++) {
if (adcRouting[i] == HWSETTINGS_ADCROUTING_BATTERYVOLTAGE) {
voltageADCPin = i;
}
if (adcRouting[i] == HWSETTINGS_ADCROUTING_BATTERYCURRENT) {
currentADCPin = i;
}
}
// Don't enable module if no ADC pins are routed to the sensors
if (voltageADCPin < 0 && currentADCPin < 0) {
batteryEnabled = false;
}
// Start module
if (batteryEnabled) {
FlightBatteryStateInitialize();
FlightBatterySettingsInitialize();
// FlightBatterySettingsConnectCallback(FlightBatterySettingsUpdatedCb);
static UAVObjEvent ev;
memset(&ev, 0, sizeof(UAVObjEvent));
EventPeriodicCallbackCreate(&ev, onTimer, SAMPLE_PERIOD_MS / portTICK_RATE_MS);
}
return 0;
}
MODULE_INITCALL(BatteryInitialize, 0);
static void onTimer(__attribute__((unused)) UAVObjEvent *ev)
{
static FlightBatterySettingsData batterySettings;
static FlightBatteryStateData flightBatteryData;
FlightBatterySettingsGet(&batterySettings);
FlightBatteryStateGet(&flightBatteryData);
const float dT = SAMPLE_PERIOD_MS / 1000.0f;
float energyRemaining;
// calculate the battery parameters
if (voltageADCPin >= 0) {
flightBatteryData.Voltage = (PIOS_ADC_PinGetVolt(voltageADCPin) - batterySettings.SensorCalibrations.VoltageZero) * batterySettings.SensorCalibrations.VoltageFactor; // in Volts
} else {
flightBatteryData.Voltage = 0; // Dummy placeholder value. This is in case we get another source of battery current which is not from the ADC
}
// voltage available: get the number of cells if possible, desired and not armed
GetNbCells(&batterySettings, &flightBatteryData);
// ad a plausibility check: zero voltage => zero current
if (currentADCPin >= 0 && flightBatteryData.Voltage > 0.f) {
flightBatteryData.Current = (PIOS_ADC_PinGetVolt(currentADCPin) - batterySettings.SensorCalibrations.CurrentZero) * batterySettings.SensorCalibrations.CurrentFactor; // in Amps
if (flightBatteryData.Current > flightBatteryData.PeakCurrent) {
flightBatteryData.PeakCurrent = flightBatteryData.Current; // in Amps
}
} else { // If there's no current measurement, we still need to assign one. Make it negative, so it can never trigger an alarm
flightBatteryData.Current = -0; // Dummy placeholder value. This is in case we get another source of battery current which is not from the ADC
}
// For safety reasons consider only positive currents in energy comsumption, i.e. no charging up.
// necesary when sensor are not perfectly calibrated
if (flightBatteryData.Current > 0) {
flightBatteryData.ConsumedEnergy += (flightBatteryData.Current * dT * 1000.0f / 3600.0f); // in mAh
}
// Apply a 2 second rise time low-pass filter to average the current
float alpha = 1.0f - dT / (dT + 2.0f);
flightBatteryData.AvgCurrent = alpha * flightBatteryData.AvgCurrent + (1 - alpha) * flightBatteryData.Current; // in Amps
/*The motor could regenerate power. Or we could have solar cells.
In short, is there any likelihood of measuring negative current? If it's a bad current reading we want to check, then
it makes sense to saturate at max and min values, because a misreading could as easily be very large, as negative. The simple
sign check doesn't catch this.*/
energyRemaining = batterySettings.Capacity - flightBatteryData.ConsumedEnergy; // in mAh
if (batterySettings.Capacity > 0 && flightBatteryData.AvgCurrent > 0) {
flightBatteryData.EstimatedFlightTime = (energyRemaining / (flightBatteryData.AvgCurrent * 1000.0f)) * 3600.0f; // in Sec
} else {
flightBatteryData.EstimatedFlightTime = 0;
}
// generate alarms where needed...
if ((flightBatteryData.Voltage <= 0) && (flightBatteryData.Current <= 0)) {
// FIXME: There's no guarantee that a floating ADC will give 0. So this
// check might fail, even when there's nothing attached.
AlarmsSet(SYSTEMALARMS_ALARM_BATTERY, SYSTEMALARMS_ALARM_ERROR);
AlarmsSet(SYSTEMALARMS_ALARM_FLIGHTTIME, SYSTEMALARMS_ALARM_ERROR);
} else {
// FIXME: should make the timer alarms user configurable
if (batterySettings.Capacity > 0 && flightBatteryData.EstimatedFlightTime < 30) {
AlarmsSet(SYSTEMALARMS_ALARM_FLIGHTTIME, SYSTEMALARMS_ALARM_CRITICAL);
} else if (batterySettings.Capacity > 0 && flightBatteryData.EstimatedFlightTime < 120) {
AlarmsSet(SYSTEMALARMS_ALARM_FLIGHTTIME, SYSTEMALARMS_ALARM_WARNING);
} else {
AlarmsClear(SYSTEMALARMS_ALARM_FLIGHTTIME);
}
// FIXME: should make the battery voltage detection dependent on battery type.
/*Not so sure. Some users will want to run their batteries harder than others, so it should be the user's choice. [KDS]*/
if (flightBatteryData.Voltage < batterySettings.CellVoltageThresholds.Alarm * flightBatteryData.NbCells) {
AlarmsSet(SYSTEMALARMS_ALARM_BATTERY, SYSTEMALARMS_ALARM_CRITICAL);
} else if (flightBatteryData.Voltage < batterySettings.CellVoltageThresholds.Warning * flightBatteryData.NbCells) {
AlarmsSet(SYSTEMALARMS_ALARM_BATTERY, SYSTEMALARMS_ALARM_WARNING);
} else {
AlarmsClear(SYSTEMALARMS_ALARM_BATTERY);
}
}
FlightBatteryStateSet(&flightBatteryData);
}
static int8_t GetNbCells(const FlightBatterySettingsData *batterySettings, FlightBatteryStateData *flightBatteryData)
{
// get flight status to check for armed
uint8_t armed = 0;
FlightStatusArmedGet(&armed);
// check only if not armed
if (armed == FLIGHTSTATUS_ARMED_ARMED) {
return -2;
}
// prescribed number of cells?
if (batterySettings->NbCells != 0) {
flightBatteryData->NbCells = batterySettings->NbCells;
flightBatteryData->NbCellsAutodetected = 0;
return -3;
}
// plausibility check
if (flightBatteryData->Voltage <= 0.5f) {
// cannot detect number of cells
flightBatteryData->NbCellsAutodetected = 0;
return -1;
}
float voltageMin = 0.f, voltageMax = 0.f;
// Cell type specific values
// TODO: could be implemented as constant arrays indexed by cellType
// or could be part of the UAVObject definition
switch (batterySettings->Type) {
case FLIGHTBATTERYSETTINGS_TYPE_LIPO:
case FLIGHTBATTERYSETTINGS_TYPE_LICO:
voltageMin = 3.6f;
voltageMax = 4.2f;
break;
case FLIGHTBATTERYSETTINGS_TYPE_A123:
voltageMin = 2.01f;
voltageMax = 3.59f;
break;
case FLIGHTBATTERYSETTINGS_TYPE_LIFESO4:
default:
flightBatteryData->NbCellsAutodetected = 0;
return -1;
}
// uniquely measurable under any condition iff n * voltageMax < (n+1) * voltageMin
// or n < voltageMin / (voltageMax-voltageMin)
// weaken condition by setting n <= voltageMin / (voltageMax-voltageMin) and
// checking for v <= voltageMin * voltageMax / (voltageMax-voltageMin)
if (flightBatteryData->Voltage > voltageMin * voltageMax / (voltageMax - voltageMin)) {
flightBatteryData->NbCellsAutodetected = 0;
return -1;
}
flightBatteryData->NbCells = (int8_t)(flightBatteryData->Voltage / voltageMin);
flightBatteryData->NbCellsAutodetected = 1;
return flightBatteryData->NbCells;
}
/**
* @}
*/
/**
* @}
*/