WeatherVane.cpp

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/**
 * @file WeatherVane.cpp
 * Weathervane controller.
 *
 */

#include "WeatherVane.hpp"
#include <mathlib/mathlib.h>


WeatherVane::WeatherVane() :
    ModuleParams(nullptr)
{ }

void WeatherVane::update(const matrix::Vector3f &dcm_z_sp_prev, float yaw)
{
    _dcm_z_sp_prev = dcm_z_sp_prev;
    _yaw = yaw;
}

float WeatherVane::get_weathervane_yawrate()
{
    // direction of desired body z axis represented in earth frame
    matrix::Vector3f body_z_sp(_dcm_z_sp_prev);

    // rotate desired body z axis into new frame which is rotated in z by the current
    // heading of the vehicle. we refer to this as the heading frame.
    matrix::Dcmf R_yaw = matrix::Eulerf(0.0f, 0.0f, -_yaw);
    body_z_sp = R_yaw * body_z_sp;
    body_z_sp.normalize();

    float roll_sp = -asinf(body_z_sp(1));

    float roll_exceeding_treshold = 0.0f;
    float min_roll_rad = math::radians(_param_wv_roll_min.get());

    if (roll_sp > min_roll_rad) {
        roll_exceeding_treshold = roll_sp - min_roll_rad;

    } else if (roll_sp < -min_roll_rad) {
        roll_exceeding_treshold = roll_sp + min_roll_rad;
    }

    return math::constrain(roll_exceeding_treshold * _param_wv_gain.get(), -math::radians(_param_wv_yrate_max.get()),
                   math::radians(_param_wv_yrate_max.get()));
}