mirror of https://github.com/ArduPilot/ardupilot
269 lines
7.8 KiB
C++
269 lines
7.8 KiB
C++
// -*- tab-width: 4; Mode: C++; c-basic-offset: 3; indent-tabs-mode: t -*-
|
|
/*
|
|
AP_Compass_HMC5843.cpp - Arduino Library for HMC5843 I2C magnetometer
|
|
Code by Jordi Muñoz and Jose Julio. DIYDrones.com
|
|
|
|
This library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
Sensor is conected to I2C port
|
|
Sensor is initialized in Continuos mode (10Hz)
|
|
|
|
Variables:
|
|
heading : magnetic heading
|
|
heading_x : magnetic heading X component
|
|
heading_y : magnetic heading Y component
|
|
mag_x : Raw X axis magnetometer data
|
|
mag_y : Raw Y axis magnetometer data
|
|
mag_z : Raw Z axis magnetometer data
|
|
last_update : the time of the last successful reading
|
|
|
|
Methods:
|
|
init() : Initialization of I2C and sensor
|
|
read() : Read Sensor data
|
|
calculate(float roll, float pitch) : Calculate tilt adjusted heading
|
|
set_orientation(const Matrix3f &rotation_matrix) : Set orientation of compass
|
|
set_offsets(int x, int y, int z) : Set adjustments for HardIron disturbances
|
|
set_declination(float radians) : Set heading adjustment between true north and magnetic north
|
|
|
|
To do : code optimization
|
|
Mount position : UPDATED
|
|
Big capacitor pointing backward, connector forward
|
|
|
|
*/
|
|
|
|
// AVR LibC Includes
|
|
#include <math.h>
|
|
#include "WConstants.h"
|
|
|
|
#include <Wire.h>
|
|
#include "AP_Compass_HMC5843.h"
|
|
|
|
#define COMPASS_ADDRESS 0x1E
|
|
#define ConfigRegA 0x00
|
|
#define ConfigRegB 0x01
|
|
#define magGain 0x20
|
|
#define PositiveBiasConfig 0x11
|
|
#define NegativeBiasConfig 0x12
|
|
#define NormalOperation 0x10
|
|
#define ModeRegister 0x02
|
|
#define ContinuousConversion 0x00
|
|
#define SingleConversion 0x01
|
|
|
|
// Constructors ////////////////////////////////////////////////////////////////
|
|
AP_Compass_HMC5843::AP_Compass_HMC5843() : orientation(0), declination(0.0)
|
|
{
|
|
// mag x y z offset initialisation
|
|
|
|
_offset.x = 0;
|
|
_offset.y = 0;
|
|
_offset.z = 0;
|
|
|
|
// initialise orientation matrix
|
|
orientation_matrix = ROTATION_NONE;
|
|
}
|
|
|
|
// Public Methods //////////////////////////////////////////////////////////////
|
|
bool AP_Compass_HMC5843::init(int initialise_wire_lib)
|
|
{
|
|
unsigned long currentTime = millis(); // record current time
|
|
int numAttempts = 0;
|
|
int success = 0;
|
|
first_call = 1;
|
|
|
|
if( initialise_wire_lib != 0 )
|
|
Wire.begin();
|
|
|
|
delay(10);
|
|
|
|
// calibration initialisation
|
|
calibration[0] = 1.0;
|
|
calibration[1] = 1.0;
|
|
calibration[2] = 1.0;
|
|
|
|
while( success == 0 && numAttempts < 5 )
|
|
{
|
|
// record number of attempts at initialisation
|
|
numAttempts++;
|
|
|
|
// force positiveBias (compass should return 715 for all channels)
|
|
Wire.beginTransmission(COMPASS_ADDRESS);
|
|
Wire.send(ConfigRegA);
|
|
Wire.send(PositiveBiasConfig);
|
|
if (0 != Wire.endTransmission())
|
|
continue; // compass not responding on the bus
|
|
delay(50);
|
|
|
|
// set gains
|
|
Wire.beginTransmission(COMPASS_ADDRESS);
|
|
Wire.send(ConfigRegB);
|
|
Wire.send(magGain);
|
|
Wire.endTransmission();
|
|
delay(10);
|
|
|
|
Wire.beginTransmission(COMPASS_ADDRESS);
|
|
Wire.send(ModeRegister);
|
|
Wire.send(SingleConversion);
|
|
Wire.endTransmission();
|
|
delay(10);
|
|
|
|
// read values from the compass
|
|
read();
|
|
delay(10);
|
|
|
|
// calibrate
|
|
if( abs(mag_x) > 500 && abs(mag_x) < 1000 && abs(mag_y) > 500 && abs(mag_y) < 1000 && abs(mag_z) > 500 && abs(mag_z) < 1000)
|
|
{
|
|
calibration[0] = fabs(715.0 / mag_x);
|
|
calibration[1] = fabs(715.0 / mag_y);
|
|
calibration[2] = fabs(715.0 / mag_z);
|
|
|
|
// mark success
|
|
success = 1;
|
|
}
|
|
|
|
// leave test mode
|
|
Wire.beginTransmission(COMPASS_ADDRESS);
|
|
Wire.send(ConfigRegA);
|
|
Wire.send(NormalOperation);
|
|
Wire.endTransmission();
|
|
delay(50);
|
|
|
|
Wire.beginTransmission(COMPASS_ADDRESS);
|
|
Wire.send(ModeRegister);
|
|
Wire.send(ContinuousConversion); // Set continuous mode (default to 10Hz)
|
|
Wire.endTransmission(); // End transmission
|
|
delay(50);
|
|
}
|
|
return(success);
|
|
}
|
|
|
|
// Read Sensor data
|
|
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
|
|
Wire.endTransmission(); //end transmission
|
|
|
|
//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++;
|
|
}
|
|
Wire.endTransmission(); //end transmission
|
|
|
|
if (i==6) // All bytes received?
|
|
{
|
|
// MSB byte first, then LSB, X,Y,Z
|
|
mag_x = -((((int)buff[0]) << 8) | buff[1]) * calibration[0]; // X axis
|
|
mag_y = ((((int)buff[2]) << 8) | buff[3]) * calibration[1]; // Y axis
|
|
mag_z = -((((int)buff[4]) << 8) | buff[5]) * calibration[2]; // Z axis
|
|
last_update = millis(); // record time of update
|
|
// rotate the magnetometer values depending upon orientation
|
|
if( orientation == 0 )
|
|
rot_mag = Vector3f(mag_x,mag_y,mag_z);
|
|
else
|
|
rot_mag = orientation_matrix*Vector3f(mag_x,mag_y,mag_z);
|
|
rot_mag = rot_mag + _offset;
|
|
mag_x = rot_mag.x;
|
|
mag_y = rot_mag.y;
|
|
mag_z = rot_mag.z;
|
|
}
|
|
}
|
|
|
|
void AP_Compass_HMC5843::calculate(float roll, float pitch)
|
|
{
|
|
float headX;
|
|
float headY;
|
|
float cos_roll;
|
|
float sin_roll;
|
|
float cos_pitch;
|
|
float sin_pitch;
|
|
|
|
cos_roll = cos(roll); // Optimizacion, se puede sacar esto de la matriz DCM?
|
|
sin_roll = 1 - (cos_roll * cos_roll);
|
|
cos_pitch = cos(pitch);
|
|
sin_pitch = 1 - (cos_pitch * cos_pitch);
|
|
|
|
// Tilt compensated magnetic field X component:
|
|
headX = mag_x*cos_pitch+mag_y*sin_roll*sin_pitch+mag_z*cos_roll*sin_pitch;
|
|
// Tilt compensated magnetic field Y component:
|
|
headY = mag_y*cos_roll-mag_z*sin_roll;
|
|
// magnetic heading
|
|
heading = atan2(-headY,headX);
|
|
|
|
// Declination correction (if supplied)
|
|
if( declination != 0.0 )
|
|
{
|
|
heading = heading + declination;
|
|
if (heading > M_PI) // Angle normalization (-180 deg, 180 deg)
|
|
heading -= (2.0 * M_PI);
|
|
else if (heading < -M_PI)
|
|
heading += (2.0 * M_PI);
|
|
}
|
|
|
|
// Optimization for external DCM use. Calculate normalized components
|
|
heading_x = cos(heading);
|
|
heading_y = sin(heading);
|
|
}
|
|
|
|
|
|
void AP_Compass_HMC5843::null_offsets(Matrix3f dcm_matrix)
|
|
{
|
|
// Update our estimate of the offsets in the magnetometer
|
|
Vector3f calc(0.0, 0.0, 0.0);
|
|
Matrix3f dcm_new_from_last;
|
|
float weight;
|
|
|
|
Vector3f mag_body_new = Vector3f(mag_x,mag_y,mag_z);
|
|
|
|
if(!first_call) {
|
|
dcm_new_from_last = dcm_matrix.transposed() * last_dcm_matrix; // Note 11/20/2010: transpose() is not working, transposed() is.
|
|
|
|
weight = 3.0 - fabs(dcm_new_from_last.a.x) - fabs(dcm_new_from_last.b.y) - fabs(dcm_new_from_last.c.z);
|
|
if (weight > .001) {
|
|
calc = mag_body_new + mag_body_last; // Eq 11 from Bill P's paper
|
|
calc -= dcm_new_from_last * mag_body_last;
|
|
calc -= dcm_new_from_last.transposed() * mag_body_new;
|
|
if(weight > 0.5) weight = 0.5;
|
|
calc = calc * (weight);
|
|
_offset -= calc;
|
|
}
|
|
|
|
} else {
|
|
first_call = 0;
|
|
}
|
|
mag_body_last = mag_body_new - calc;
|
|
last_dcm_matrix = dcm_matrix;
|
|
|
|
}
|
|
|
|
void AP_Compass_HMC5843::set_orientation(const Matrix3f &rotation_matrix)
|
|
{
|
|
orientation_matrix = rotation_matrix;
|
|
if( orientation_matrix == ROTATION_NONE )
|
|
orientation = 0;
|
|
else
|
|
orientation = 1;
|
|
}
|
|
|
|
void AP_Compass_HMC5843::set_offsets(int x, int y, int z)
|
|
{
|
|
_offset.x = x;
|
|
_offset.y = y;
|
|
_offset.z = z;
|
|
}
|
|
|
|
void AP_Compass_HMC5843::set_declination(float radians)
|
|
{
|
|
declination = radians;
|
|
}
|