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LibrePilot/flight/Modules/Attitude/attitude.c
James Cotton 86b652bbab Merge branch 'next' into camera_stabilization
2011-08-14 18:07:57 -05:00

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/**
******************************************************************************
* @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 "attitudesettings.h"
#include "flightstatus.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 int8_t updateSensors(AttitudeRawData *);
static void updateAttitude(AttitudeRawData *);
static void settingsUpdatedCb(UAVObjEvent * objEv);
static float accelKi = 0;
static float accelKp = 0;
static float yawBiasRate = 0;
static float gyroGain = 0.42;
static int16_t accelbias[3];
static float q[4] = {1,0,0,0};
static float R[3][3];
static int8_t rotate = 0;
static bool zero_during_arming = false;
static bool bias_correct_gyro = true;
/**
* Initialise the module, called on startup
* \returns 0 on success or -1 if initialisation failed
*/
int32_t AttitudeStart(void)
{
// 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;
}
/**
* Initialise the module, called on startup
* \returns 0 on success or -1 if initialisation failed
*/
int32_t AttitudeInitialize(void)
{
AttitudeActualInitialize();
AttitudeRawInitialize();
AttitudeSettingsInitialize();
// Initialize quaternion
AttitudeActualData attitude;
AttitudeActualGet(&attitude);
attitude.q1 = 1;
attitude.q2 = 0;
attitude.q3 = 0;
attitude.q4 = 0;
AttitudeActualSet(&attitude);
// Cannot trust the values to init right above if BL runs
gyro_correct_int[0] = 0;
gyro_correct_int[1] = 0;
gyro_correct_int[2] = 0;
q[0] = 1;
q[1] = 0;
q[2] = 0;
q[3] = 0;
for(uint8_t i = 0; i < 3; i++)
for(uint8_t j = 0; j < 3; j++)
R[i][j] = 0;
// 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);
return 0;
}
MODULE_INITCALL(AttitudeInitialize, AttitudeStart)
/**
* 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();
// Set critical error and wait until the accel is producing data
while(PIOS_ADXL345_FifoElements() == 0) {
AlarmsSet(SYSTEMALARMS_ALARM_ATTITUDE, SYSTEMALARMS_ALARM_CRITICAL);
PIOS_WDG_UpdateFlag(PIOS_WDG_ATTITUDE);
}
// Force settings update to make sure rotation loaded
settingsUpdatedCb(AttitudeSettingsHandle());
// Main task loop
while (1) {
FlightStatusData flightStatus;
FlightStatusGet(&flightStatus);
if((xTaskGetTickCount() < 7000) && (xTaskGetTickCount() > 1000)) {
// For first 7 seconds use accels to get gyro bias
accelKp = 1;
accelKi = 0.9;
yawBiasRate = 0.23;
init = 0;
}
else if (zero_during_arming && (flightStatus.Armed == FLIGHTSTATUS_ARMED_ARMING)) {
accelKp = 1;
accelKi = 0.9;
yawBiasRate = 0.23;
init = 0;
} else if (init == 0) {
// Reload settings (all the rates)
AttitudeSettingsAccelKiGet(&accelKi);
AttitudeSettingsAccelKpGet(&accelKp);
AttitudeSettingsYawBiasRateGet(&yawBiasRate);
init = 1;
}
PIOS_WDG_UpdateFlag(PIOS_WDG_ATTITUDE);
AttitudeRawData attitudeRaw;
AttitudeRawGet(&attitudeRaw);
if(updateSensors(&attitudeRaw) != 0)
AlarmsSet(SYSTEMALARMS_ALARM_ATTITUDE, SYSTEMALARMS_ALARM_ERROR);
else {
// Only update attitude when sensor data is good
updateAttitude(&attitudeRaw);
AttitudeRawSet(&attitudeRaw);
AlarmsClear(SYSTEMALARMS_ALARM_ATTITUDE);
}
}
}
/**
* Get an update from the sensors
* @param[in] attitudeRaw Populate the UAVO instead of saving right here
* @return 0 if successfull, -1 if not
*/
static int8_t 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 -1;
}
// No accel data available
if(PIOS_ADXL345_FifoElements() == 0)
return -1;
// 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;
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;
float accel[3] = {(float) x / i, (float) y / i, (float) z / i};
if(rotate) {
// TODO: rotate sensors too so stabilization is well behaved
float vec_out[3];
rot_mult(R, accel, vec_out);
attitudeRaw->accels[0] = vec_out[0];
attitudeRaw->accels[1] = vec_out[1];
attitudeRaw->accels[2] = vec_out[2];
rot_mult(R, attitudeRaw->gyros, vec_out);
attitudeRaw->gyros[0] = vec_out[0];
attitudeRaw->gyros[1] = vec_out[1];
attitudeRaw->gyros[2] = vec_out[2];
} else {
attitudeRaw->accels[0] = accel[0];
attitudeRaw->accels[1] = accel[1];
attitudeRaw->accels[2] = accel[2];
}
// Scale accels and correct bias
attitudeRaw->accels[ATTITUDERAW_ACCELS_X] = (attitudeRaw->accels[ATTITUDERAW_ACCELS_X] - accelbias[0]) * 0.004f * 9.81f;
attitudeRaw->accels[ATTITUDERAW_ACCELS_Y] = (attitudeRaw->accels[ATTITUDERAW_ACCELS_Y] - accelbias[1]) * 0.004f * 9.81f;
attitudeRaw->accels[ATTITUDERAW_ACCELS_Z] = (attitudeRaw->accels[ATTITUDERAW_ACCELS_Z] - accelbias[2]) * 0.004f * 9.81f;
if(bias_correct_gyro) {
// 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];
attitudeRaw->gyros[ATTITUDERAW_GYROS_Z] += gyro_correct_int[2];
}
// Because most crafts wont get enough information from gravity to zero yaw gyro, we try
// and make it average zero (weakly)
gyro_correct_int[2] += - attitudeRaw->gyros[ATTITUDERAW_GYROS_Z] * yawBiasRate;
return 0;
}
static void updateAttitude(AttitudeRawData * attitudeRaw)
{
float dT;
portTickType thisSysTime = xTaskGetTickCount();
static portTickType lastSysTime = 0;
dT = (thisSysTime == lastSysTime) ? 0.001 : (portMAX_DELAY & (thisSysTime - lastSysTime)) / portTICK_RATE_MS / 1000.0f;
lastSysTime = thisSysTime;
// Bad practice to assume structure order, but saves memory
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 (deg/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];
if(q[0] < 0) {
q[0] = -q[0];
q[1] = -q[1];
q[2] = -q[2];
q[3] = -q[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;
// If quaternion has become inappropriately short or is nan reinit.
// THIS SHOULD NEVER ACTUALLY HAPPEN
if((fabs(qmag) < 1e-3) || (qmag != qmag)) {
q[0] = 1;
q[1] = 0;
q[2] = 0;
q[3] = 0;
}
AttitudeActualData attitudeActual;
AttitudeActualGet(&attitudeActual);
quat_copy(q, &attitudeActual.q1);
// Convert into eueler degrees (makes assumptions about RPY order)
Quaternion2RPY(&attitudeActual.q1,&attitudeActual.Roll);
AttitudeActualSet(&attitudeActual);
}
static void settingsUpdatedCb(UAVObjEvent * objEv) {
AttitudeSettingsData attitudeSettings;
AttitudeSettingsGet(&attitudeSettings);
accelKp = attitudeSettings.AccelKp;
accelKi = attitudeSettings.AccelKi;
yawBiasRate = attitudeSettings.YawBiasRate;
gyroGain = attitudeSettings.GyroGain;
zero_during_arming = attitudeSettings.ZeroDuringArming == ATTITUDESETTINGS_ZERODURINGARMING_TRUE;
bias_correct_gyro = attitudeSettings.BiasCorrectGyro == ATTITUDESETTINGS_BIASCORRECTGYRO_TRUE;
accelbias[0] = attitudeSettings.AccelBias[ATTITUDESETTINGS_ACCELBIAS_X];
accelbias[1] = attitudeSettings.AccelBias[ATTITUDESETTINGS_ACCELBIAS_Y];
accelbias[2] = attitudeSettings.AccelBias[ATTITUDESETTINGS_ACCELBIAS_Z];
gyro_correct_int[0] = attitudeSettings.GyroBias[ATTITUDESETTINGS_GYROBIAS_X] / 100.0f;
gyro_correct_int[1] = attitudeSettings.GyroBias[ATTITUDESETTINGS_GYROBIAS_Y] / 100.0f;
gyro_correct_int[2] = attitudeSettings.GyroBias[ATTITUDESETTINGS_GYROBIAS_Z] / 100.0f;
// Indicates not to expend cycles on rotation
if(attitudeSettings.BoardRotation[0] == 0 && attitudeSettings.BoardRotation[1] == 0 &&
attitudeSettings.BoardRotation[2] == 0) {
rotate = 0;
// Shouldn't be used but to be safe
float rotationQuat[4] = {1,0,0,0};
Quaternion2R(rotationQuat, R);
} else {
float rotationQuat[4];
const float rpy[3] = {attitudeSettings.BoardRotation[ATTITUDESETTINGS_BOARDROTATION_ROLL],
attitudeSettings.BoardRotation[ATTITUDESETTINGS_BOARDROTATION_PITCH],
attitudeSettings.BoardRotation[ATTITUDESETTINGS_BOARDROTATION_YAW]};
RPY2Quaternion(rpy, rotationQuat);
Quaternion2R(rotationQuat, R);
rotate = 1;
}
}
/**
* @}
* @}
*/
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