ardupilot/libraries/AP_LandingGear/AP_LandingGear.h

// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-

/// @file	AP_LandingGear.h
/// @brief	Landing gear control library
#pragma once

#include <AP_Param/AP_Param.h>
#include <AP_Common/AP_Common.h>

#define AP_LANDINGGEAR_SERVO_RETRACT_PWM_DEFAULT    1250    // default PWM value to move servo to when landing gear is up
#define AP_LANDINGGEAR_SERVO_DEPLOY_PWM_DEFAULT     1750    // default PWM value to move servo to when landing gear is down

// Gear command modes
enum LandingGearCommandMode {
    LandingGear_Deploy,
    LandingGear_Auto,
    LandingGear_Retract
};

/// @class	AP_LandingGear
/// @brief	Class managing the control of landing gear
class AP_LandingGear {

public:

    /// Constructor
    AP_LandingGear() :
        _retract_enabled(false),
        _deployed(false),
        _force_deploy(false),
        _command_mode(LandingGear_Deploy)
    {
        // setup parameter defaults
        AP_Param::setup_object_defaults(this, var_info);
    }

    /// enabled - returns true if landing gear retract is enabled
    bool enabled() const { return _retract_enabled; }

    /// deployed - returns true if the landing gear is deployed
    bool deployed() const { return _deployed; }

    /// update - should be called at 10hz
    void update();

    /// set_cmd_mode - set command mode to deploy, auto or retract
    void set_cmd_mode(LandingGearCommandMode cmd) { _command_mode = cmd; }

    /// force_deploy - set to true to force gear to deploy
    void force_deploy(bool force) { _force_deploy = force;}

    static const struct AP_Param::GroupInfo        var_info[];

private:

    bool     _retract_enabled;          // true if landing gear retraction is enabled

    // Parameters
    AP_Int16    _servo_retract_pwm;     // PWM value to move servo to when gear is retracted
    AP_Int16    _servo_deploy_pwm;      // PWM value to move servo to when gear is deployed

    // internal variables
    bool        _deployed;              // true if the landing gear has been deployed, initialized false
    bool        _force_deploy;          // used by main code to force landing gear to deploy, such as in Land mode
    LandingGearCommandMode  _command_mode;  // pilots commanded control mode: Manual Deploy, Auto, or Manual Retract
    
    /// enable - enable landing gear retraction
    void enable(bool on_off);
    
    /// retract - retract landing gear
    void retract();
    
    /// deploy - deploy the landing gear
    void deploy();
};