/home/travis/build/lis-epfl/MAVRIC_Library/sensing/ahrs_madgwick.hpp

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/*******************************************************************************
 * \file ahrs_madgwick.hpp
 *
 * \author MAV'RIC Team
 * \author SOH Madgwick
 * \author Julien Lecoeur
 * \author Simon Pyroth
 *
 * \brief Implementation of Madgwick's AHRS algorithms.
 *
 * See: http://www.x-io.co.uk/node/8#open_source_ahrs_and_imu_algorithms
 *
 * Date         Author          Notes
 * 29/09/2011   SOH Madgwick    Initial release
 * 02/10/2011   SOH Madgwick    Optimised for reduced CPU load
 * 19/02/2012   SOH Madgwick    Magnetometer measurement is normalised
 * 04/02/2014   Julien Lecoeur  Adapt to MAVRIC
 *
 ******************************************************************************/


#ifndef AHRS_MADGWICK_HPP_
#define AHRS_MADGWICK_HPP_

#include "sensing/ahrs.hpp"
#include "sensing/imu.hpp"
#include "drivers/airspeed_analog.hpp"


class AHRS_madgwick: public AHRS
{
public:
    struct conf_t
    {
        float   beta;                       // 2 * proportional gain (Kp)
        float   zeta;                       // Gyro drift bias gain
        bool    acceleration_correction;    // Enable the correction of the parasitic accelerations ?
        float   correction_speed;           // Airspeed from which the correction should start
    };


    static inline conf_t default_config()
    {
        conf_t conf = {};

        conf.beta = 0.06f;
        conf.zeta = 0.0f;
        conf.acceleration_correction = false;
        conf.correction_speed        = 0.0f;

        return conf;
    };


    AHRS_madgwick(const Imu& imu, const Airspeed_analog& airspeed, const conf_t& config = default_config());


    bool update(void);


    float last_update_s(void) const;


    bool is_healthy(void) const;


    quat_t attitude(void) const;


    std::array<float,3> angular_speed(void) const;


    std::array<float,3> linear_acceleration(void) const;

protected:
    const Imu&             imu_;                      
    const Airspeed_analog& airspeed_;                 

    quat_t              attitude_;              
    std::array<float,3> angular_speed_;         
    std::array<float,3> linear_acc_;            
    float               last_update_s_;         

    float            beta_;                     
    float            zeta_;                     
    uint32_t         acceleration_correction_;  
    float            correction_speed_;         

private:
    // Global variables used in the Madgwick algorithm.
    // Quaternions used for the Madgwick algorithm. They are in the MADGWICK FRAME, not in the MAVRIC FRAME !
    float q0_, q1_, q2_, q3_;

    // Estimated gyro biases. Warning: they are also expressed in MADGWICK FRAME ! Transformation has to be made to express them in MAVRIC FRAME !
    float w_bx_, w_by_, w_bz_;

    void madgwick_algo(float gx, float gy, float gz, float ax, float ay, float az, float mx, float my, float mz, float beta, float zeta, float dt);
};

#endif /* AHRS_MADGWICK_HPP_ */