MulticopterLandDetector.h

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/**
 * @file MulticopterLandDetector.h
 * Land detection implementation for multicopters.
 *
 * @author Johan Jansen <jnsn.johan@gmail.com>
 * @author Morten Lysgaard <morten@lysgaard.no>
 * @author Julian Oes <julian@oes.ch>
 */

#pragma once

#include <uORB/topics/actuator_controls.h>
#include <uORB/topics/battery_status.h>
#include <uORB/topics/vehicle_angular_velocity.h>
#include <uORB/topics/vehicle_attitude.h>
#include <uORB/topics/vehicle_control_mode.h>
#include <uORB/topics/vehicle_local_position_setpoint.h>

#include "LandDetector.h"

using namespace time_literals;

namespace land_detector
{

class MulticopterLandDetector : public LandDetector
{
public:
    MulticopterLandDetector();
    ~MulticopterLandDetector() override = default;

protected:
    void _update_params() override;
    void _update_topics() override;

    bool _get_landed_state() override;
    bool _get_ground_contact_state() override;
    bool _get_maybe_landed_state() override;
    bool _get_freefall_state() override;
    bool _get_ground_effect_state() override;

    float _get_max_altitude() override;
private:

    /** Get control mode dependent pilot throttle threshold with which we should quit landed state and take off. */
    float _get_takeoff_throttle();

    bool _has_low_thrust();
    bool _has_minimal_thrust();
    bool _has_altitude_lock();
    bool _has_position_lock();
    bool _is_climb_rate_enabled();

    /** Time in us that landing conditions have to hold before triggering a land. */
    static constexpr hrt_abstime LAND_DETECTOR_TRIGGER_TIME_US = 300_ms;

    /** Time in us that almost landing conditions have to hold before triggering almost landed . */
    static constexpr hrt_abstime MAYBE_LAND_DETECTOR_TRIGGER_TIME_US = 250_ms;

    /** Time in us that ground contact condition have to hold before triggering contact ground */
    static constexpr hrt_abstime GROUND_CONTACT_TRIGGER_TIME_US = 350_ms;

    /** Time interval in us in which wider acceptance thresholds are used after landed. */
    static constexpr hrt_abstime LAND_DETECTOR_LAND_PHASE_TIME_US = 2_s;

    /** Handles for interesting parameters. **/
    struct {
        param_t minThrottle;
        param_t hoverThrottle;
        param_t minManThrottle;
        param_t landSpeed;
    } _paramHandle{};

    struct {
        float minThrottle;
        float hoverThrottle;
        float minManThrottle;
        float landSpeed;
    } _params{};

    uORB::Subscription _actuator_controls_sub{ORB_ID(actuator_controls_0)};
    uORB::Subscription _battery_sub{ORB_ID(battery_status)};
    uORB::Subscription _vehicle_acceleration_sub{ORB_ID(vehicle_acceleration)};
    uORB::Subscription _vehicle_angular_velocity_sub{ORB_ID(vehicle_angular_velocity)};
    uORB::Subscription _vehicle_control_mode_sub{ORB_ID(vehicle_control_mode)};
    uORB::Subscription _vehicle_local_position_sub{ORB_ID(vehicle_local_position)};
    uORB::Subscription _vehicle_local_position_setpoint_sub{ORB_ID(vehicle_local_position_setpoint)};

    actuator_controls_s               _actuator_controls {};
    battery_status_s                  _battery_status {};
    vehicle_angular_velocity_s        _vehicle_angular_velocity{};
    vehicle_control_mode_s            _vehicle_control_mode {};
    vehicle_local_position_setpoint_s _vehicle_local_position_setpoint {};

    hrt_abstime _min_trust_start{0};    ///< timestamp when minimum trust was applied first
    hrt_abstime _landed_time{0};

    bool _in_descend{false};        ///< vehicle is desending
    bool _horizontal_movement{false};   ///< vehicle is moving horizontally

    DEFINE_PARAMETERS_CUSTOM_PARENT(
        LandDetector,
        (ParamFloat<px4::params::LNDMC_ALT_MAX>)    _param_lndmc_alt_max,
        (ParamFloat<px4::params::LNDMC_FFALL_THR>)  _param_lndmc_ffall_thr,
        (ParamFloat<px4::params::LNDMC_FFALL_TTRI>) _param_lndmc_ffall_ttri,
        (ParamFloat<px4::params::LNDMC_LOW_T_THR>)  _param_lndmc_low_t_thr,
        (ParamFloat<px4::params::LNDMC_ROT_MAX>)    _param_lndmc_rot_max,
        (ParamFloat<px4::params::LNDMC_XY_VEL_MAX>) _param_lndmc_xy_vel_max,
        (ParamFloat<px4::params::LNDMC_Z_VEL_MAX>)  _param_lndmc_z_vel_max
    );
};

} // namespace land_detector