/****************************************************************************
*
* Copyright (C) 2008-2012 PX4 Development Team. All rights reserved.
* Author: @author Thomas Gubler <thomasgubler@student.ethz.ch>
*
* 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
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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****************************************************************************/
/*
* @file: landingslope.h
*
*/
#ifndef LANDINGSLOPE_H_
#define LANDINGSLOPE_H_
#include <math.h>
#include <systemlib/err.h>
class Landingslope
{
private:
/* see Documentation/fw_landing.png for a plot of the landing slope */
float _landing_slope_angle_rad; /**< phi in the plot */
float _flare_relative_alt; /**< h_flare,rel in the plot */
float _motor_lim_relative_alt;
float _H1_virt; /**< H1 in the plot */
float _H0; /**< h_flare,rel + H1 in the plot */
float _d1; /**< d1 in the plot */
float _flare_constant;
float _flare_length; /**< d1 + delta d in the plot */
float _horizontal_slope_displacement; /**< delta d in the plot */
void calculateSlopeValues();
public:
Landingslope() {}
~Landingslope() {}
/**
*
* @return relative altitude of point on landing slope at distance to landing waypoint=wp_landing_distance
*/
float getLandingSlopeRelativeAltitude(float wp_landing_distance);
/**
*
* @return relative altitude of point on landing slope at distance to landing waypoint=wp_landing_distance
* Performs check if aircraft is in front of waypoint to avoid climbout
*/
float getLandingSlopeRelativeAltitudeSave(float wp_landing_distance, float bearing_lastwp_currwp, float bearing_airplane_currwp);
/**
*
* @return Absolute altitude of point on landing slope at distance to landing waypoint=wp_landing_distance
*/
float getLandingSlopeAbsoluteAltitude(float wp_landing_distance, float wp_altitude);
/**
*
* @return Absolute altitude of point on landing slope at distance to landing waypoint=wp_landing_distance
* Performs check if aircraft is in front of waypoint to avoid climbout
*/
float getLandingSlopeAbsoluteAltitudeSave(float wp_landing_distance, float bearing_lastwp_currwp, float bearing_airplane_currwp, float wp_landing_altitude);
/**
*
* @return Relative altitude of point on landing slope at distance to landing waypoint=wp_landing_distance
*/
__EXPORT static float getLandingSlopeRelativeAltitude(float wp_landing_distance, float horizontal_slope_displacement, float landing_slope_angle_rad)
{
return (wp_landing_distance - horizontal_slope_displacement) * tanf(landing_slope_angle_rad); //flare_relative_alt is negative
}
/**
*
* @return Absolute altitude of point on landing slope at distance to landing waypoint=wp_landing_distance
*/
__EXPORT static float getLandingSlopeAbsoluteAltitude(float wp_landing_distance, float wp_landing_altitude, float horizontal_slope_displacement, float landing_slope_angle_rad)
{
return getLandingSlopeRelativeAltitude(wp_landing_distance, horizontal_slope_displacement, landing_slope_angle_rad) + wp_landing_altitude;
}
/**
*
* @return distance to landing waypoint of point on landing slope at altitude=slope_altitude
*/
__EXPORT static float getLandingSlopeWPDistance(float slope_altitude, float wp_landing_altitude, float horizontal_slope_displacement, float landing_slope_angle_rad)
{
return (slope_altitude - wp_landing_altitude)/tanf(landing_slope_angle_rad) + horizontal_slope_displacement;
}
float getFlareCurveRelativeAltitudeSave(float wp_distance, float bearing_lastwp_currwp, float bearing_airplane_currwp);
float getFlareCurveAbsoluteAltitudeSave(float wp_distance, float bearing_lastwp_currwp, float bearing_airplane_currwp, float wp_altitude);
void update(float landing_slope_angle_rad_new,
float flare_relative_alt_new,
float motor_lim_relative_alt_new,
float H1_virt_new);
inline float landing_slope_angle_rad() {return _landing_slope_angle_rad;}
inline float flare_relative_alt() {return _flare_relative_alt;}
inline float motor_lim_relative_alt() {return _motor_lim_relative_alt;}
inline float H1_virt() {return _H1_virt;}
inline float H0() {return _H0;}
inline float d1() {return _d1;}
inline float flare_constant() {return _flare_constant;}
inline float flare_length() {return _flare_length;}
inline float horizontal_slope_displacement() {return _horizontal_slope_displacement;}
};
#endif /* LANDINGSLOPE_H_ */
