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Compass: several fixes to compass calibration code 

this changes the calibration code to require at least 5 good reads
from the compass during initialisation. The calibration is taken as
the average of the 5 values.

This also fixes the expected values for the 3 axes for the 5883 to
match reality.

We also save a bit of code space by adding a common rotate_for_5883L()
routine.

git-svn-id: https://arducopter.googlecode.com/svn/trunk@3087 f9c3cf11-9bcb-44bc-f272-b75c42450872
This commit is contained in:
tridge60@gmail.com 2011-08-13 08:17:25 +00:00
parent 5ffd66bc83
commit 32c576f28c
2 changed files with 125 additions and 74 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

180
libraries/AP_Compass/AP_Compass_HMC5843.cpp
View File

@ -83,17 +83,73 @@ write_register(int address, byte value)
return true;
}
/*
the 5883L has a different orientation to the 5843. This allows us to
use a single MAG_ORIENTATION for both
*/
static void rotate_for_5883L(AP_VarS<Matrix3f> *_orientation_matrix)
{
_orientation_matrix->set_and_save(_orientation_matrix->get() * Matrix3f(ROTATION_YAW_90));
}
// Read Sensor data
bool AP_Compass_HMC5843::read_raw()
{
int i = 0;
byte buff[6];
Wire.beginTransmission(COMPASS_ADDRESS);
Wire.send(0x03); //sends address to read from
if (0 != Wire.endTransmission())
return false;
Wire.requestFrom(COMPASS_ADDRESS, 6); // request 6 bytes from device
while (Wire.available()) {
buff[i] = Wire.receive(); // receive one byte
i++;
}
if (0 != Wire.endTransmission())
return false;
if (i != 6) {
/* we didn't get enough bytes */
return false;
}
int16_t rx, ry, rz;
rx = (int16_t)(buff[0] << 8) | buff[1];
if (product_id == AP_COMPASS_TYPE_HMC5883L) {
rz = (int16_t)(buff[2] << 8) | buff[3];
ry = (int16_t)(buff[4] << 8) | buff[5];
} else {
ry = (int16_t)(buff[2] << 8) | buff[3];
rz = (int16_t)(buff[4] << 8) | buff[5];
}
if (rx == -4096 || ry == -4096 || rz == -4096) {
// no valid data available
return false;
}
mag_x = -rx;
mag_y = ry;
mag_z = -rz;
return true;
}
// Public Methods //////////////////////////////////////////////////////////////
bool
AP_Compass_HMC5843::init()
{
int numAttempts = 0;
int numAttempts = 0, good_count = 0;
bool success = false;
byte base_config; // used to test compass type
byte calibration_gain = 0x20;
uint16_t expected_xy = 715;
uint16_t expected_z = 715;
uint16_t expected_x = 715;
uint16_t expected_yz = 715;
delay(10);
@ -108,15 +164,14 @@ AP_Compass_HMC5843::init()
product_id = AP_COMPASS_TYPE_HMC5883L;
calibration_gain = 0x60;
expected_xy = 766;
expected_z = 713;
expected_x = 766;
expected_yz = 713;
if (old_product_id != product_id) {
/* now we know the compass type we need to rotate the
* orientation matrix that we were given
*/
Matrix3f rot_mat = _orientation_matrix.get();
_orientation_matrix.set_and_save(rot_mat * Matrix3f(ROTATION_YAW_90));
rotate_for_5883L(&_orientation_matrix);
}
} else if (base_config == (NormalOperation | DataOutputRate_75HZ<<2)) {
product_id = AP_COMPASS_TYPE_HMC5843;
@ -125,11 +180,12 @@ AP_Compass_HMC5843::init()
return false;
}
calibration[0] = 0;
calibration[1] = 0;
calibration[2] = 0;
while( success == 0 && numAttempts < 5 )
while ( success == 0 && numAttempts < 20 && good_count < 5)
{
unsigned long update_stamp = last_update;
// record number of attempts at initialisation
numAttempts++;
@ -143,29 +199,55 @@ AP_Compass_HMC5843::init()
! write_register(ModeRegister, SingleConversion))
continue;
// calibration initialisation
calibration[0] = 1.0;
calibration[1] = 1.0;
calibration[2] = 1.0;
// read values from the compass
delay(50);
read();
if (last_update == update_stamp)
if (!read_raw())
continue; // we didn't read valid values
delay(10);
// calibrate
if( abs(mag_x) > 500 && abs(mag_x) < 2000 && abs(mag_y) > 500 && abs(mag_y) < 2000 && abs(mag_z) > 500 && abs(mag_z) < 2000)
{
calibration[0] = fabs(expected_xy / (float)mag_x);
calibration[1] = fabs(expected_xy / (float)mag_y);
calibration[2] = fabs(expected_z / (float)mag_z);
float cal[3];
// mark success
success = true;
cal[0] = fabs(expected_x / (float)mag_x);
cal[1] = fabs(expected_yz / (float)mag_y);
cal[2] = fabs(expected_yz / (float)mag_z);
if (cal[0] > 0.7 && cal[0] < 1.3 &&
cal[1] > 0.7 && cal[1] < 1.3 &&
cal[2] > 0.7 && cal[2] < 1.3) {
good_count++;
calibration[0] += cal[0];
calibration[1] += cal[1];
calibration[2] += cal[2];
}
#if 0
/* useful for debugging */
Serial.print("mag_x: ");
Serial.print(mag_x);
Serial.print(" mag_y: ");
Serial.print(mag_y);
Serial.print(" mag_z: ");
Serial.println(mag_z);
Serial.print("CalX: ");
Serial.print(calibration[0]/good_count);
Serial.print(" CalY: ");
Serial.print(calibration[1]/good_count);
Serial.print(" CalZ: ");
Serial.println(calibration[2]/good_count);
#endif
}
if (good_count >= 5) {
calibration[0] /= good_count;
calibration[1] /= good_count;
calibration[2] /= good_count;
success = true;
} else {
/* best guess */
calibration[0] = 1.0;
calibration[1] = 1.0;
calibration[2] = 1.0;
}
// leave test mode
@ -184,63 +266,31 @@ AP_Compass_HMC5843::init()
void
AP_Compass_HMC5843::read()
{
int i = 0;
byte buff[6];
Vector3f rot_mag;
Wire.beginTransmission(COMPASS_ADDRESS);
Wire.send(0x03); //sends address to read from
if (0 != Wire.endTransmission())
return;
//Wire.beginTransmission(COMPASS_ADDRESS);
Wire.requestFrom(COMPASS_ADDRESS, 6); // request 6 bytes from device
while(Wire.available())
{
buff[i] = Wire.receive(); // receive one byte
i++;
}
if (0 != Wire.endTransmission())
return;
if (i==6) // All bytes received?
{
int16_t rx, ry, rz;
rx = (int16_t)(buff[0] << 8) | buff[1];
if (product_id == AP_COMPASS_TYPE_HMC5883L) {
rz = (int16_t)(buff[2] << 8) | buff[3];
ry = (int16_t)(buff[4] << 8) | buff[5];
} else {
ry = (int16_t)(buff[2] << 8) | buff[3];
rz = (int16_t)(buff[4] << 8) | buff[5];
}
if (rx == -4096 || ry == -4096 || rz == -4096) {
// no valid data available, last_update is not updated
if (!read_raw()) {
return;
}
mag_x = -rx * calibration[0];
mag_y = ry * calibration[1];
mag_z = -rz * calibration[2];
mag_x *= calibration[0];
mag_y *= calibration[1];
mag_z *= calibration[2];
last_update = millis(); // record time of update
// rotate and offset the magnetometer values
// XXX this could well be done in common code...
rot_mag = _orientation_matrix.get() * Vector3f(mag_x,mag_y,mag_z);
Vector3f rot_mag = _orientation_matrix.get() * Vector3f(mag_x,mag_y,mag_z);
rot_mag = rot_mag + _offset.get();
mag_x = rot_mag.x;
mag_y = rot_mag.y;
mag_z = rot_mag.z;
}
}
// set orientation
void
AP_Compass_HMC5843::set_orientation(const Matrix3f &rotation_matrix)
{
if( product_id == AP_COMPASS_TYPE_HMC5883L ) {
_orientation_matrix.set_and_save(rotation_matrix * Matrix3f(ROTATION_YAW_90));
}else{
_orientation_matrix.set_and_save(rotation_matrix);
if (product_id == AP_COMPASS_TYPE_HMC5883L) {
rotate_for_5883L(&_orientation_matrix);
}
}

1
libraries/AP_Compass/AP_Compass_HMC5843.h
View File

@ -50,6 +50,7 @@ class AP_Compass_HMC5843 : public Compass
AP_Compass_HMC5843(AP_Var::Key key = AP_Var::k_key_none) : Compass(key) {}
virtual bool init();
virtual void read();
virtual bool read_raw();
virtual void set_orientation(const Matrix3f &rotation_matrix);
};