move landing slope calculations into own class

4 files changed, 180 insertions, 25 deletions

diff --git a/src/modules/fw_pos_control_l1/fw_pos_control_l1_main.cpp b/src/modules/fw_pos_control_l1/fw_pos_control_l1_main.cpp
index eb84c49d1..ae0f8c0ea 100644
--- a/src/modules/fw_pos_control_l1/fw_pos_control_l1_main.cpp
+++ b/src/modules/fw_pos_control_l1/fw_pos_control_l1_main.cpp
@@ -87,6 +87,7 @@
 
 #include <ecl/l1/ecl_l1_pos_controller.h>
 #include <external_lgpl/tecs/tecs.h>
+#include "landingslope.h"
 
 /**
  * L1 control app start / stop handling function
@@ -168,6 +169,9 @@ private:
 	bool land_motor_lim;
 	bool land_onslope;
 
+	/* Landingslope object */
+	Landingslope landingslope;
+
 	float flare_curve_alt_last;
 	/* heading hold */
 	float target_bearing;
@@ -308,11 +312,6 @@ private:
 	void		vehicle_setpoint_poll();
 
 	/**
-	 * Get Altitude on the landing glide slope
-	 */
-	float getLandingSlopeAbsoluteAltitude(float wp_distance, float wp_altitude, float landing_slope_angle_rad, float horizontal_displacement);
-
-	/**
 	 * Control position.
 	 */
 	bool		control_position(const math::Vector2f &global_pos, const math::Vector2f &ground_speed,
@@ -536,6 +535,9 @@ FixedwingPositionControl::parameters_update()
 		return 1;
 	}
 
+	/* Update the landing slope */
+	landingslope.update(math::radians(_parameters.land_slope_angle), _parameters.land_flare_alt_relative, _parameters.land_thrust_lim_horizontal_distance, _parameters.land_H1_virt);
+
 	return OK;
 }
 
@@ -707,11 +709,6 @@ FixedwingPositionControl::calculate_gndspeed_undershoot(const math::Vector2f &cu
 	}
 }
 
-float FixedwingPositionControl::getLandingSlopeAbsoluteAltitude(float wp_distance, float wp_altitude, float landing_slope_angle_rad, float horizontal_displacement)
-{
-	return (wp_distance - horizontal_displacement) * tanf(landing_slope_angle_rad) + wp_altitude; //flare_relative_alt is negative
-}
-
 bool
 FixedwingPositionControl::control_position(const math::Vector2f &current_position, const math::Vector2f &ground_speed,
 		const struct mission_item_triplet_s &mission_item_triplet)
@@ -854,20 +851,13 @@ FixedwingPositionControl::control_position(const math::Vector2f &current_positio
 			float airspeed_land = 1.3f * _parameters.airspeed_min;
 			float airspeed_approach = 1.3f * _parameters.airspeed_min;
 
-			float landing_slope_angle_rad = math::radians(_parameters.land_slope_angle);
-			float flare_relative_alt = _parameters.land_flare_alt_relative;
-			float motor_lim_horizontal_distance = _parameters.land_thrust_lim_horizontal_distance;//be generous here as we currently have to rely on the user input for the waypoint
 			float L_wp_distance = get_distance_to_next_waypoint(prev_wp.getX(), prev_wp.getY(), curr_wp.getX(), curr_wp.getY()) * _parameters.land_slope_length;
-			float H1 = _parameters.land_H1_virt;
-			float H0 = flare_relative_alt + H1;
-			float d1 = flare_relative_alt/tanf(landing_slope_angle_rad);
-			float flare_constant = (H0 * d1)/flare_relative_alt;//-flare_length/(logf(H1/H0));
-			float flare_length = - logf(H1/H0) * flare_constant;//d1+20.0f;//-logf(0.01f/flare_relative_alt);
-			float horizontal_slope_displacement = (flare_length - d1);
-			float L_altitude = getLandingSlopeAbsoluteAltitude(L_wp_distance, _mission_item_triplet.current.altitude, landing_slope_angle_rad, horizontal_slope_displacement);
-			float landing_slope_alt_desired = getLandingSlopeAbsoluteAltitude(wp_distance, _mission_item_triplet.current.altitude, landing_slope_angle_rad, horizontal_slope_displacement);
+			float L_altitude = landingslope.getLandingSlopeAbsoluteAltitude(L_wp_distance, _mission_item_triplet.current.altitude);//getLandingSlopeAbsoluteAltitude(L_wp_distance, _mission_item_triplet.current.altitude, landing_slope_angle_rad, horizontal_slope_displacement);
+			float landing_slope_alt_desired = landingslope.getLandingSlopeAbsoluteAltitude(wp_distance, _mission_item_triplet.current.altitude);//getLandingSlopeAbsoluteAltitude(wp_distance, _mission_item_triplet.current.altitude, landing_slope_angle_rad, horizontal_slope_displacement);
+
+
 
-			if ( (_global_pos.alt < _mission_item_triplet.current.altitude + flare_relative_alt) || land_noreturn_vertical) {  //checking for land_noreturn to avoid unwanted climb out
+			if ( (_global_pos.alt < _mission_item_triplet.current.altitude + landingslope.flare_relative_alt()) || land_noreturn_vertical) {  //checking for land_noreturn to avoid unwanted climb out
 
 				/* land with minimal speed */
 
@@ -877,7 +867,7 @@ FixedwingPositionControl::control_position(const math::Vector2f &current_positio
 				/* kill the throttle if param requests it */
 				throttle_max = _parameters.throttle_max;
 
-				 if (wp_distance < motor_lim_horizontal_distance || land_motor_lim) {
+				 if (wp_distance < landingslope.motor_lim_horizontal_distance() || land_motor_lim) {
 					throttle_max = math::min(throttle_max, _parameters.throttle_land_max);
 					if (!land_motor_lim) {
 						land_motor_lim  = true;
@@ -886,7 +876,7 @@ FixedwingPositionControl::control_position(const math::Vector2f &current_positio
 
 				 }
 
-				float flare_curve_alt =   _mission_item_triplet.current.altitude + H0 * expf(-math::max(0.0f, flare_length - wp_distance)/flare_constant) - H1;
+				float flare_curve_alt =   _mission_item_triplet.current.altitude + landingslope.H0() * expf(-math::max(0.0f, landingslope.flare_length() - wp_distance)/landingslope.flare_constant()) - landingslope.H1_virt();
 
 				/* avoid climbout */
 				if (flare_curve_alt_last < flare_curve_alt && land_noreturn_vertical || land_stayonground)
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
+}
+
diff --git a/src/modules/fw_pos_control_l1/landingslope.h b/src/modules/fw_pos_control_l1/landingslope.h
new file mode 100644
index 000000000..f855b796f
--- /dev/null
+++ b/src/modules/fw_pos_control_l1/landingslope.h
@@ -0,0 +1,86 @@
+/****************************************************************************
+ *
+ *   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.h
+ *
+ * @author: Thomas Gubler <thomasgubler@gmail.com>
+ */
+
+#ifndef LANDINGSLOPE_H_
+#define LANDINGSLOPE_H_
+
+class Landingslope
+{
+private:
+	float _landing_slope_angle_rad;
+	float _flare_relative_alt;
+	float _motor_lim_horizontal_distance;
+	float _H1_virt;
+	float _H0;
+	float _d1;
+	float _flare_constant;
+	float _flare_length;
+	float _horizontal_slope_displacement;
+
+	void calculateSlopeValues();
+
+public:
+	Landingslope() {}
+	~Landingslope() {}
+
+	float getLandingSlopeAbsoluteAltitude(float wp_distance, float wp_altitude);
+
+	void update(float landing_slope_angle_rad,
+			float flare_relative_alt,
+			float motor_lim_horizontal_distance,
+			float H1_virt);
+
+
+	inline float landing_slope_angle_rad() {return _landing_slope_angle_rad;}
+	inline float flare_relative_alt() {return _flare_relative_alt;}
+	inline float motor_lim_horizontal_distance() {return _motor_lim_horizontal_distance;}
+	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_ */
diff --git a/src/modules/fw_pos_control_l1/module.mk b/src/modules/fw_pos_control_l1/module.mk
index b00b9aa5a..cf419ec7e 100644
--- a/src/modules/fw_pos_control_l1/module.mk
+++ b/src/modules/fw_pos_control_l1/module.mk
@@ -38,4 +38,5 @@
 MODULE_COMMAND	= fw_pos_control_l1
 
 SRCS		= fw_pos_control_l1_main.cpp \
-		  fw_pos_control_l1_params.c
+		  fw_pos_control_l1_params.c \
+		  landingslope.cpp