ardupilot/libraries/AP_AHRS/AP_AHRS_MPU6000.h

120 lines
3.2 KiB
C++

#ifndef __AP_AHRS_MPU6000_H__
#define __AP_AHRS_MPU6000_H__
/*
* DCM based AHRS (Attitude Heading Reference System) interface for
* ArduPilot
*
* 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.
*/
// Rate of the gyro bias from gravity correction (200Hz/4) => 50Hz
#define GYRO_BIAS_FROM_GRAVITY_RATE 4
// Initial value to detect that compass correction is not initialized
#define HEADING_UNKNOWN -9999
// max rate of gyro drift in gyro_LSB_units/s (16.4LSB = 1deg/s)
// 0.5 corresponds to 0.03 degrees/s/s;
static const float _MPU6000_gyro_drift_rate = 0.5;
class AP_AHRS_MPU6000 : public AP_AHRS
{
public:
// Constructors
AP_AHRS_MPU6000(AP_InertialSensor_MPU6000 *mpu6000, GPS *&gps) :
AP_AHRS(mpu6000, gps),
// ki and ki_yaw are experimentally derived from the simulator
_ki(0.0087),
_ki_yaw(0.01),
_mpu6000(mpu6000),
// dmp related variable initialisation
_compass_bias_time(0),
_gyro_bias_from_gravity_gain(0.008)
{
_dcm_matrix.identity();
}
// initialisation routine to start MPU6000's dmp
void init();
// return the smoothed gyro vector corrected for drift
Vector3f get_gyro(void) {
return _ins->get_gyro();
}
Matrix3f get_dcm_matrix(void) {
return _dcm_matrix;
}
// return the current drift correction integrator value
Vector3f get_gyro_drift(void) {
return _omega_I;
}
// Methods
void update(void);
void reset(bool recover_eulers = false);
// push offsets down from IMU to INS (required so MPU6000 can perform it's
// own attitude estimation)
void push_offsets_to_ins();
void push_gains_to_dmp();
// status reporting
float get_error_rp(void);
float get_error_yaw(void);
// set_as_secondary - avoid running some steps twice (imu updates) if
// this is a secondary ahrs
void set_as_secondary(bool secondary) {
_secondary_ahrs = secondary;
}
private:
float _ki;
float _ki_yaw;
AP_InertialSensor_MPU6000 *_mpu6000;
// Methods
void drift_correction(float deltat);
// Compass correction variables. TO-DO: move or replace?
// TO-DO: move wrap_PI to standard AP_AHRS methods
float wrap_PI(float angle_in_radians);
long _compass_bias_time;
void drift_correction_yaw(void);
float yaw_error_compass();
void euler_angles(void);
Vector3f _accel_filtered;
int16_t _accel_filtered_samples;
// bias_tracking
float _gyro_bias[3];
// bias correction algorithm gain
float _gyro_bias_from_gravity_gain;
uint8_t _gyro_bias_from_gravity_counter;
// primary representation of attitude
Matrix3f _dcm_matrix;
// current accel vector
Vector3f _accel_vector;
// Omega Integrator correction
Vector3f _omega_I;
Vector3f _omega_I_sum;
float _omega_I_sum_time;
// state to support status reporting
float _error_yaw_sum;
uint16_t _error_yaw_count;
float _error_yaw_last;
bool _secondary_ahrs;
};
#endif // __AP_AHRS_MPU6000_H__