/****************************************************************************
*
* Copyright (C) 2008-2012 PX4 Development Team. All rights reserved.
* Author: @author Lorenz Meier <lm@inf.ethz.ch>
* @author Thomas Gubler <thomasgubler@student.ethz.ch>
* @author Julian Oes <joes@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
* 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: landingslope.cpp
*
* @author: Thomas Gubler <thomasgubler@gmail.com>
*/
#include "landingslope.h"
#include <nuttx/config.h>
#include <stdlib.h>
#include <errno.h>
#include <math.h>
#include <unistd.h>
#include <mathlib/mathlib.h>
void Landingslope::update(float landing_slope_angle_rad,
float flare_relative_alt,
float motor_lim_horizontal_distance,
float H1_virt)
{
_landing_slope_angle_rad = landing_slope_angle_rad;
_flare_relative_alt = flare_relative_alt;
_motor_lim_horizontal_distance = motor_lim_horizontal_distance;
_H1_virt = H1_virt;
calculateSlopeValues();
}
void Landingslope::calculateSlopeValues()
{
_H0 = _flare_relative_alt + _H1_virt;
_d1 = _flare_relative_alt/tanf(_landing_slope_angle_rad);
_flare_constant = (_H0 * _d1)/_flare_relative_alt;
_flare_length = - logf(_H1_virt/_H0) * _flare_constant;
_horizontal_slope_displacement = (_flare_length - _d1);
}
float Landingslope::getLandingSlopeAbsoluteAltitude(float wp_distance, float wp_altitude)
{
return (wp_distance - _horizontal_slope_displacement) * tanf(_landing_slope_angle_rad) + wp_altitude; //flare_relative_alt is negative
}
float Landingslope::getFlarceCurveAltitude(float wp_distance, float wp_altitude)
{
return wp_altitude + _H0 * expf(-math::max(0.0f, _flare_length - wp_distance)/_flare_constant) - _H1_virt;
}
