precland.h

Go to the documentation of this file.

/***************************************************************************
 *
 *   Copyright (c) 2017 PX4 Development Team. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name PX4 nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/
/**
 * @file precland.h
 *
 * Helper class to do precision landing with a landing target
 *
 * @author Nicolas de Palezieux (Sunflower Labs) <ndepal@gmail.com>
 */

#pragma once

#include <matrix/math.hpp>
#include <lib/ecl/geo/geo.h>
#include <px4_platform_common/module_params.h>
#include <uORB/Subscription.hpp>
#include <uORB/topics/landing_target_pose.h>

#include "navigator_mode.h"
#include "mission_block.h"

enum class PrecLandState {
    Start, // Starting state
    HorizontalApproach, // Positioning over landing target while maintaining altitude
    DescendAboveTarget, // Stay over landing target while descending
    FinalApproach, // Final landing approach, even without landing target
    Search, // Search for landing target
    Fallback, // Fallback landing method
    Done // Done landing
};

enum class PrecLandMode {
    Opportunistic = 1, // only do precision landing if landing target visible at the beginning
    Required = 2 // try to find landing target if not visible at the beginning
};

class PrecLand : public MissionBlock, public ModuleParams
{
public:
    PrecLand(Navigator *navigator);
    ~PrecLand() override = default;

    void on_activation() override;
    void on_active() override;

    void set_mode(PrecLandMode mode) { _mode = mode; };

    PrecLandMode get_mode() { return _mode; };

private:

    void updateParams() override;

    // run the control loop for each state
    void run_state_start();
    void run_state_horizontal_approach();
    void run_state_descend_above_target();
    void run_state_final_approach();
    void run_state_search();
    void run_state_fallback();

    // attempt to switch to a different state. Returns true if state change was successful, false otherwise
    bool switch_to_state_start();
    bool switch_to_state_horizontal_approach();
    bool switch_to_state_descend_above_target();
    bool switch_to_state_final_approach();
    bool switch_to_state_search();
    bool switch_to_state_fallback();
    bool switch_to_state_done();

    // check if a given state could be changed into. Return true if possible to transition to state, false otherwise
    bool check_state_conditions(PrecLandState state);
    void slewrate(float &sp_x, float &sp_y);

    landing_target_pose_s _target_pose{}; /**< precision landing target position */

    uORB::Subscription _target_pose_sub{ORB_ID(landing_target_pose)};
    bool _target_pose_valid{false}; /**< whether we have received a landing target position message */
    bool _target_pose_updated{false}; /**< wether the landing target position message is updated */

    struct map_projection_reference_s _map_ref {}; /**< reference for local/global projections */

    uint64_t _state_start_time{0}; /**< time when we entered current state */
    uint64_t _last_slewrate_time{0}; /**< time when we last limited setpoint changes */
    uint64_t _target_acquired_time{0}; /**< time when we first saw the landing target during search */
    uint64_t _point_reached_time{0}; /**< time when we reached a setpoint */

    int _search_cnt{0}; /**< counter of how many times we had to search for the landing target */
    float _approach_alt{0.0f}; /**< altitude at which to stay during horizontal approach */

    matrix::Vector2f _sp_pev;
    matrix::Vector2f _sp_pev_prev;

    PrecLandState _state{PrecLandState::Start};

    PrecLandMode _mode{PrecLandMode::Opportunistic};

    DEFINE_PARAMETERS(
        (ParamFloat<px4::params::PLD_BTOUT>) _param_pld_btout,
        (ParamFloat<px4::params::PLD_HACC_RAD>) _param_pld_hacc_rad,
        (ParamFloat<px4::params::PLD_FAPPR_ALT>) _param_pld_fappr_alt,
        (ParamFloat<px4::params::PLD_SRCH_ALT>) _param_pld_srch_alt,
        (ParamFloat<px4::params::PLD_SRCH_TOUT>) _param_pld_srch_tout,
        (ParamInt<px4::params::PLD_MAX_SRCH>) _param_pld_max_srch
    )

    // non-navigator parameters
    param_t _handle_param_acceleration_hor{PARAM_INVALID};
    param_t _handle_param_xy_vel_cruise{PARAM_INVALID};
    float   _param_acceleration_hor{0.0f};
    float   _param_xy_vel_cruise{0.0f};

};