mirror of https://github.com/ArduPilot/ardupilot
108 lines
3.5 KiB
C++
108 lines
3.5 KiB
C++
#ifndef AP_AHRS_MPU6000_H
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#define AP_AHRS_MPU6000_H
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/*
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* DCM based AHRS (Attitude Heading Reference System) interface for
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* ArduPilot
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*/
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#define GYRO_BIAS_FROM_GRAVITY_RATE 4 // Rate of the gyro bias from gravity correction (200Hz/4) => 50Hz
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#define HEADING_UNKNOWN -9999 // Initial value to detect that compass correction is not initialized
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// max rate of gyro drift in gyro_LSB_units/s (16.4LSB = 1deg/s)
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static const float _MPU6000_gyro_drift_rate = 0.5; // This correspond to 0.03 degrees/s/s;
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class AP_AHRS_MPU6000 : public AP_AHRS
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{
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public:
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// Constructors
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AP_AHRS_MPU6000(AP_IMU_INS *imu, GPS *&gps, AP_InertialSensor_MPU6000 *mpu6000) : AP_AHRS(imu, gps), _mpu6000(mpu6000)
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{
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_dcm_matrix.identity();
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// these are experimentally derived from the simulator
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// with large drift levels
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_ki = 0.0087;
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_ki_yaw = 0.01;
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// dmp related variable initialisation
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_gyro_bias_from_gravity_gain = 0.008;
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_compass_bias_time = 0;
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}
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// initialisation routine to start MPU6000's dmp
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void init( AP_PeriodicProcess * scheduler = NULL );
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// return the smoothed gyro vector corrected for drift
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Vector3f get_gyro(void) {
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return _imu->get_gyro();
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}
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Matrix3f get_dcm_matrix(void) {
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return _dcm_matrix;
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}
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// return the current drift correction integrator value
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Vector3f get_gyro_drift(void) {
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return _omega_I;
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}
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// Methods
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void update(void);
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void reset(bool recover_eulers = false);
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// push offsets down from IMU to INS (required so MPU6000 can perform it's own attitude estimation)
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void push_offsets_to_ins();
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void push_gains_to_dmp();
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// status reporting
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float get_error_rp(void);
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float get_error_yaw(void);
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// set_as_secondary - avoid running some steps twice (imu updates) if this is a secondary ahrs
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void set_as_secondary(bool secondary) { _secondary_ahrs = secondary; }
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private:
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float _ki;
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float _ki_yaw;
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AP_InertialSensor_MPU6000 *_mpu6000;
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// Methods
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void drift_correction(float deltat);
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// Compass correction variables. TO-DO: move or replace?
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float wrap_PI(float angle_in_radians); // TO-DO: move this to standard AP_AHRS methods
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long _compass_bias_time;
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void drift_correction_yaw(void);
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float yaw_error_compass();
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void euler_angles(void);
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Vector3f _accel_filtered;
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int16_t _accel_filtered_samples;
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float _gyro_bias[3]; // bias_tracking
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float _gyro_bias_from_gravity_gain; // bias correction algorithm gain
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uint8_t _gyro_bias_from_gravity_counter;
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// primary representation of attitude
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Matrix3f _dcm_matrix;
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Vector3f _accel_vector; // current accel vector
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Vector3f _omega_I; // Omega Integrator correction
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Vector3f _omega_I_sum;
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float _omega_I_sum_time;
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// state to support status reporting
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float _error_yaw_sum;
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uint16_t _error_yaw_count;
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float _error_yaw_last;
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bool _secondary_ahrs;
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};
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#endif // AP_AHRS_MPU6000_H
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