move landing slope calculations into own class

1 files changed, 78 insertions, 0 deletions

diff --git a/src/modules/fw_pos_control_l1/landingslope.cpp b/src/modules/fw_pos_control_l1/landingslope.cpp
new file mode 100644
index 000000000..ecf51b740
--- /dev/null
+++ b/src/modules/fw_pos_control_l1/landingslope.cpp
@@ -0,0 +1,78 @@
+/****************************************************************************
+ *
+ *   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>
+
+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
+}
+