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LibrePilot/flight/Modules/Attitude/attitude.c
peabody124 3afdc7e41c CC-24: Rotate the CC board at any angle relative to "flat and level" with GCS 
config plugin updates.  Has not been tested in flight yet although seems
sensible so please be careful when using this code.

git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@3166 ebee16cc-31ac-478f-84a7-5cbb03baadba
2011-04-15 06:37:16 +00:00

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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 "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 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;
/**
* 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);
yawBiasRate = 0.01 / (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;
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;
// 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] * yawBiasRate;
}
static void updateAttitude(AttitudeRawData * attitudeRaw)
{
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 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;
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);
float rotationQuat[4];
accelKp = attitudeSettings.AccelKp;
accelKi = attitudeSettings.AccelKi;
yawBiasRate = attitudeSettings.YawBiasRate;
gyroGain = attitudeSettings.GyroGain;
accelbias[0] = attitudeSettings.AccelBias[ATTITUDESETTINGS_ACCELBIAS_X];
accelbias[1] = attitudeSettings.AccelBias[ATTITUDESETTINGS_ACCELBIAS_Y];
accelbias[2] = attitudeSettings.AccelBias[ATTITUDESETTINGS_ACCELBIAS_Z];
// Indicates not to expend cycles on rotation
if(attitudeSettings.RotationQuaternion[0] == 126) {
rotate = 0;
rotationQuat[0] = 1;
rotationQuat[1] = rotationQuat[2] = rotationQuat[3] = 0;
return;
}
rotate = 1;
rotationQuat[0] = (float) attitudeSettings.RotationQuaternion[0] / 127.0;
rotationQuat[1] = (float) attitudeSettings.RotationQuaternion[1] / 127.0f;
rotationQuat[2] = (float) attitudeSettings.RotationQuaternion[2] / 127.0f;
rotationQuat[3] = (float) attitudeSettings.RotationQuaternion[3] / 127.0f;
float len = sqrt(rotationQuat[0] * rotationQuat[0] + rotationQuat[1] * rotationQuat[1] +
rotationQuat[2] * rotationQuat[2] + rotationQuat[3] * rotationQuat[3]);
// Sanitize input. Shouldn't do anything functional.
if(len < 1e-3) {
// Really wrong value
rotationQuat[0] = 1;
rotationQuat[1] = rotationQuat[2] = rotationQuat[3] = 0;
rotate = 0;
} else {
rotationQuat[0] /= len;
rotationQuat[1] /= len;
rotationQuat[2] /= len;
rotationQuat[3] /= len;
}
Quaternion2R(rotationQuat, R);
}
/**
* @}
* @}
*/
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