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LibrePilot/flight/Modules/Attitude/attitude.c
peabody124 ea390d0b90 CC-26: Add accel bias term. Note it's units are LSB, not m/s^s
git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@2895 ebee16cc-31ac-478f-84a7-5cbb03baadba
2011-02-26 22:21:44 +00:00

328 lines
10 KiB
C

/**
******************************************************************************
* @addtogroup OpenPilotModules OpenPilot Modules
* @{
* @addtogroup Attitude Copter Control Attitude Estimation
* @brief Acquires sensor data and computes attitude estimate
* Specifically updates the the @ref AttitudeActual "AttitudeActual" and @ref AttitudeRaw "AttitudeRaw" settings objects
* @{
*
* @file attitude.c
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* @brief Module to handle all comms to the AHRS on a periodic basis.
*
* @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
*/
/**
* Input objects: None, takes sensor data via pios
* Output objects: @ref AttitudeRaw @ref AttitudeActual
*
* This module computes an attitude estimate from the sensor data
*
* The module executes in its own thread.
*
* 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 "pios.h"
#include "attitude.h"
#include "attituderaw.h"
#include "attitudeactual.h"
#include "attitudedesired.h"
#include "attitudesettings.h"
#include "manualcontrolcommand.h"
#include "CoordinateConversions.h"
#include "pios_flash_w25x.h"
// Private constants
#define STACK_SIZE_BYTES 540
#define TASK_PRIORITY (tskIDLE_PRIORITY+3)
#define UPDATE_RATE 2.0f
#define GYRO_NEUTRAL 1665
#define PI_MOD(x) (fmod(x + M_PI, M_PI * 2) - M_PI)
// Private types
// Private variables
static xTaskHandle taskHandle;
// Private functions
static void AttitudeTask(void *parameters);
static float gyro_correct_int[3] = {0,0,0};
static xQueueHandle gyro_queue;
static void updateSensors(AttitudeRawData *);
static void updateAttitude(AttitudeRawData *);
static void settingsUpdatedCb(UAVObjEvent * objEv);
static float accelKi = 0;
static float accelKp = 0;
static float gyroGain = 0.42;
static int16_t accelbias[3];
/**
* Initialise the module, called on startup
* \returns 0 on success or -1 if initialisation failed
*/
int32_t AttitudeInitialize(void)
{
// Initialize quaternion
AttitudeActualData attitude;
AttitudeActualGet(&attitude);
attitude.q1 = 1;
attitude.q2 = 0;
attitude.q3 = 0;
attitude.q4 = 0;
AttitudeActualSet(&attitude);
// Create queue for passing gyro data, allow 2 back samples in case
gyro_queue = xQueueCreate(1, sizeof(float) * 4);
if(gyro_queue == NULL)
return -1;
PIOS_ADC_SetQueue(gyro_queue);
AttitudeSettingsConnectCallback(&settingsUpdatedCb);
// Start main task
xTaskCreate(AttitudeTask, (signed char *)"Attitude", STACK_SIZE_BYTES/4, NULL, TASK_PRIORITY, &taskHandle);
TaskMonitorAdd(TASKINFO_RUNNING_ATTITUDE, taskHandle);
PIOS_WDG_RegisterFlag(PIOS_WDG_ATTITUDE);
return 0;
}
/**
* Module thread, should not return.
*/
static void AttitudeTask(void *parameters)
{
uint8_t init = 0;
AlarmsClear(SYSTEMALARMS_ALARM_ATTITUDE);
PIOS_ADC_Config((PIOS_ADC_RATE / 1000.0f) * UPDATE_RATE);
// Keep flash CS pin high while talking accel
PIOS_FLASH_DISABLE;
PIOS_ADXL345_Init();
// Main task loop
while (1) {
if(xTaskGetTickCount() < 10000) {
// For first 5 seconds use accels to get gyro bias
accelKp = 1;
// Decrease the rate of gyro learning during init
accelKi = .5 / (1 + xTaskGetTickCount() / 5000);
} else if (init == 0) {
settingsUpdatedCb(AttitudeSettingsHandle());
init = 1;
}
PIOS_WDG_UpdateFlag(PIOS_WDG_ATTITUDE);
AttitudeRawData attitudeRaw;
AttitudeRawGet(&attitudeRaw);
updateSensors(&attitudeRaw);
updateAttitude(&attitudeRaw);
AttitudeRawSet(&attitudeRaw);
}
}
static void updateSensors(AttitudeRawData * attitudeRaw)
{
struct pios_adxl345_data accel_data;
float gyro[4];
// Only wait the time for two nominal updates before setting an alarm
if(xQueueReceive(gyro_queue, (void * const) gyro, UPDATE_RATE * 2) == errQUEUE_EMPTY) {
AlarmsSet(SYSTEMALARMS_ALARM_ATTITUDE, SYSTEMALARMS_ALARM_ERROR);
return;
}
// First sample is temperature
attitudeRaw->gyros[ATTITUDERAW_GYROS_X] = -(gyro[1] - GYRO_NEUTRAL) * gyroGain;
attitudeRaw->gyros[ATTITUDERAW_GYROS_Y] = (gyro[2] - GYRO_NEUTRAL) * gyroGain;
attitudeRaw->gyros[ATTITUDERAW_GYROS_Z] = -(gyro[3] - GYRO_NEUTRAL) * gyroGain;
// Applying integral component here so it can be seen on the gyros and correct bias
attitudeRaw->gyros[ATTITUDERAW_GYROS_X] += gyro_correct_int[0];
attitudeRaw->gyros[ATTITUDERAW_GYROS_Y] += gyro_correct_int[1];
// Because most crafts wont get enough information from gravity to zero yaw gyro
attitudeRaw->gyros[ATTITUDERAW_GYROS_Z] += gyro_correct_int[2];
gyro_correct_int[2] += - attitudeRaw->gyros[ATTITUDERAW_GYROS_Z] *
accelKi;
// Get the accel data
/* uint8_t i = 0;
attitudeRaw->accels[ATTITUDERAW_ACCELS_X] = 0;
attitudeRaw->accels[ATTITUDERAW_ACCELS_Y] = 0;
attitudeRaw->accels[ATTITUDERAW_ACCELS_Z] = 0;
do {
i++;
attitudeRaw->gyrotemp[0] = PIOS_ADXL345_Read(&accel_data);
attitudeRaw->accels[ATTITUDERAW_ACCELS_X] += (float) accel_data.x * 0.004f * 9.81;
attitudeRaw->accels[ATTITUDERAW_ACCELS_Y] += -(float) accel_data.y * 0.004f * 9.81;
attitudeRaw->accels[ATTITUDERAW_ACCELS_Z] += -(float) accel_data.z * 0.004f * 9.81;
} while ( (i < 32) && (attitudeRaw->gyrotemp[0] > 0) );
attitudeRaw->gyrotemp[1] = i;
attitudeRaw->accels[ATTITUDERAW_ACCELS_X] /= i;
attitudeRaw->accels[ATTITUDERAW_ACCELS_Y] /= i;
attitudeRaw->accels[ATTITUDERAW_ACCELS_Z] /= i;
*/
int32_t x = 0;
int32_t y = 0;
int32_t z = 0;
uint8_t i = 0;
uint8_t samples_remaining;
do {
i++;
samples_remaining = PIOS_ADXL345_Read(&accel_data);
x += accel_data.x;
y += -accel_data.y;
z += -accel_data.z;
} while ( (i < 32) && (samples_remaining > 0) );
attitudeRaw->gyrotemp[0] = samples_remaining;
attitudeRaw->gyrotemp[1] = i;
x -= accelbias[0];
y -= accelbias[1];
z -= accelbias[2];
attitudeRaw->accels[ATTITUDERAW_ACCELS_X] = ((float)x * 0.004f * 9.81f) / i;
attitudeRaw->accels[ATTITUDERAW_ACCELS_Y] = ((float)y * 0.004f * 9.81f) / i;
attitudeRaw->accels[ATTITUDERAW_ACCELS_Z] = ((float)z * 0.004f * 9.81f) / i;
}
static void updateAttitude(AttitudeRawData * attitudeRaw)
{
AttitudeActualData attitudeActual;
AttitudeActualGet(&attitudeActual);
static portTickType lastSysTime = 0;
static portTickType thisSysTime;
static float dT = 0;
thisSysTime = xTaskGetTickCount();
if(thisSysTime > lastSysTime) // reuse dt in case of wraparound
dT = (thisSysTime - lastSysTime) / portTICK_RATE_MS / 1000.0f;
lastSysTime = thisSysTime;
// Bad practice to assume structure order, but saves memory
float * q = &attitudeActual.q1;
float gyro[3];
gyro[0] = attitudeRaw->gyros[0];
gyro[1] = attitudeRaw->gyros[1];
gyro[2] = attitudeRaw->gyros[2];
{
float * accels = attitudeRaw->accels;
float grot[3];
float accel_err[3];
// Rotate gravity to body frame and cross with accels
grot[0] = -(2 * (q[1] * q[3] - q[0] * q[2]));
grot[1] = -(2 * (q[2] * q[3] + q[0] * q[1]));
grot[2] = -(q[0] * q[0] - q[1]*q[1] - q[2]*q[2] + q[3]*q[3]);
CrossProduct((const float *) accels, (const float *) grot, accel_err);
// Account for accel magnitude
float accel_mag = sqrt(accels[0]*accels[0] + accels[1]*accels[1] + accels[2]*accels[2]);
accel_err[0] /= accel_mag;
accel_err[1] /= accel_mag;
accel_err[2] /= accel_mag;
// Accumulate integral of error. Scale here so that units are (rad/s) but Ki has units of s
gyro_correct_int[0] += accel_err[0] * accelKi;
gyro_correct_int[1] += accel_err[1] * accelKi;
//gyro_correct_int[2] += accel_err[2] * settings.AccelKI * dT;
// Correct rates based on error, integral component dealt with in updateSensors
gyro[0] += accel_err[0] * accelKp / dT;
gyro[1] += accel_err[1] * accelKp / dT;
gyro[2] += accel_err[2] * accelKp / dT;
}
{ // scoping variables to save memory
// Work out time derivative from INSAlgo writeup
// Also accounts for the fact that gyros are in deg/s
float qdot[4];
qdot[0] = (-q[1] * gyro[0] - q[2] * gyro[1] - q[3] * gyro[2]) * dT * M_PI / 180 / 2;
qdot[1] = (q[0] * gyro[0] - q[3] * gyro[1] + q[2] * gyro[2]) * dT * M_PI / 180 / 2;
qdot[2] = (q[3] * gyro[0] + q[0] * gyro[1] - q[1] * gyro[2]) * dT * M_PI / 180 / 2;
qdot[3] = (-q[2] * gyro[0] + q[1] * gyro[1] + q[0] * gyro[2]) * dT * M_PI / 180 / 2;
// Take a time step
q[0] = q[0] + qdot[0];
q[1] = q[1] + qdot[1];
q[2] = q[2] + qdot[2];
q[3] = q[3] + qdot[3];
}
// Renomalize
float qmag = sqrt(q[0]*q[0] + q[1]*q[1] + q[2]*q[2] + q[3]*q[3]);
q[0] = q[0] / qmag;
q[1] = q[1] / qmag;
q[2] = q[2] / qmag;
q[3] = q[3] / qmag;
attitudeActual.q1 = q[0];
attitudeActual.q2 = q[1];
attitudeActual.q3 = q[2];
attitudeActual.q4 = q[3];
// Convert into eueler degrees (makes assumptions about RPY order)
Quaternion2RPY(q,&attitudeActual.Roll);
AttitudeActualSet(&attitudeActual);
}
static void settingsUpdatedCb(UAVObjEvent * objEv) {
AttitudeSettingsData attitudeSettings;
AttitudeSettingsGet(&attitudeSettings);
accelKp = attitudeSettings.AccelKp;
accelKi = attitudeSettings.AccelKi;
gyroGain = attitudeSettings.GyroGain;
accelbias[0] = attitudeSettings.AccelBias[ATTITUDESETTINGS_ACCELBIAS_X];
accelbias[1] = attitudeSettings.AccelBias[ATTITUDESETTINGS_ACCELBIAS_Y];
accelbias[2] = attitudeSettings.AccelBias[ATTITUDESETTINGS_ACCELBIAS_Z];
}
/**
* @}
* @}
*/