integrate range finder into fw landing

2026-06-28 04:40:35 +08:00 · 2014-03-15 11:56:04 +01:00
parent e590d96c0a
commit 3317259e79
4 changed files with 138 additions and 27 deletions
@@ -89,6 +89,7 @@
 #include <launchdetection/LaunchDetector.h>
 #include <ecl/l1/ecl_l1_pos_controller.h>
 #include <external_lgpl/tecs/tecs.h>
+#include <drivers/drv_range_finder.h>
 #include "landingslope.h"


@@ -134,6 +135,7 @@ private:
 	int 		_params_sub;			/**< notification of parameter updates */
 	int 		_manual_control_sub;		/**< notification of manual control updates */
 	int		_sensor_combined_sub;		/**< for body frame accelerations */
+	int		_range_finder_sub;		/**< range finder subscription */

 	orb_advert_t	_attitude_sp_pub;		/**< attitude setpoint */
 	orb_advert_t	_nav_capabilities_pub;		/**< navigation capabilities publication */
@@ -147,6 +149,7 @@ private:
 	struct vehicle_global_position_s		_global_pos;			/**< global vehicle position */
 	struct position_setpoint_triplet_s		_pos_sp_triplet;		/**< triplet of mission items */
 	struct sensor_combined_s			_sensor_combined;		/**< for body frame accelerations */
+	struct range_finder_report 			_range_finder;			/**< range finder report */

 	perf_counter_t	_loop_perf;			/**< loop performance counter */

@@ -181,7 +184,7 @@ private:
 	/* Landingslope object */
 	Landingslope landingslope;

-	float flare_curve_alt_last;
+	float flare_curve_alt_rel_last;
 	/* heading hold */
 	float target_bearing;

@@ -239,6 +242,7 @@ private:
 		float land_flare_alt_relative;
 		float land_thrust_lim_alt_relative;
 		float land_heading_hold_horizontal_distance;
+		float range_finder_rel_alt;

 	}		_parameters;			/**< local copies of interesting parameters */

@@ -283,6 +287,7 @@ private:
 		param_t land_flare_alt_relative;
 		param_t land_thrust_lim_alt_relative;
 		param_t land_heading_hold_horizontal_distance;
+		param_t range_finder_rel_alt;

 	}		_parameter_handles;		/**< handles for interesting parameters */

@@ -308,6 +313,12 @@ private:
 	 */
 	bool		vehicle_airspeed_poll();

+	/**
+	 * Check for range finder updates.
+	 */
+	bool		range_finder_poll();
+
+
 	/**
 	 * Check for position updates.
 	 */
@@ -328,6 +339,11 @@ private:
 	 */
 	void navigation_capabilities_publish();

+	/**
+	 * Get the relative alt either from the difference between estimate and waypoint or from the laser range finder
+	 */
+	float get_relative_landingalt(float land_setpoint_alt, float current_alt, const struct range_finder_report &range_finder, float range_finder_use_relative_alt);
+
 	/**
 	 * Control position.
 	 */
@@ -384,6 +400,7 @@ FixedwingPositionControl::FixedwingPositionControl() :
 	_control_mode_sub(-1),
 	_params_sub(-1),
 	_manual_control_sub(-1),
+	_range_finder_sub(-1),

 /* publications */
 	_attitude_sp_pub(-1),
@@ -403,7 +420,7 @@ FixedwingPositionControl::FixedwingPositionControl() :
 	launch_detected(false),
 	last_manual(false),
 	usePreTakeoffThrust(false),
-	flare_curve_alt_last(0.0f),
+	flare_curve_alt_rel_last(0.0f),
 	launchDetector(),
 	_airspeed_error(0.0f),
 	_airspeed_valid(false),
@@ -417,7 +434,8 @@ FixedwingPositionControl::FixedwingPositionControl() :
 	_control_mode(),
 	_global_pos(),
 	_pos_sp_triplet(),
-	_sensor_combined()
+	_sensor_combined(),
+	_range_finder()
 {
 	_nav_capabilities.turn_distance = 0.0f;

@@ -442,6 +460,7 @@ FixedwingPositionControl::FixedwingPositionControl() :
 	_parameter_handles.land_flare_alt_relative = param_find("FW_LND_FLALT");
 	_parameter_handles.land_thrust_lim_alt_relative = param_find("FW_LND_TLALT");
 	_parameter_handles.land_heading_hold_horizontal_distance = param_find("FW_LND_HHDIST");
+	_parameter_handles.range_finder_rel_alt = param_find("FW_LND_RFRALT");

 	_parameter_handles.time_const = 			param_find("FW_T_TIME_CONST");
 	_parameter_handles.min_sink_rate = 			param_find("FW_T_SINK_MIN");
@@ -531,6 +550,8 @@ FixedwingPositionControl::parameters_update()
 	param_get(_parameter_handles.land_thrust_lim_alt_relative, &(_parameters.land_thrust_lim_alt_relative));
 	param_get(_parameter_handles.land_heading_hold_horizontal_distance, &(_parameters.land_heading_hold_horizontal_distance));

+	param_get(_parameter_handles.range_finder_rel_alt, &(_parameters.range_finder_rel_alt));
+
 	_l1_control.set_l1_damping(_parameters.l1_damping);
 	_l1_control.set_l1_period(_parameters.l1_period);
 	_l1_control.set_l1_roll_limit(math::radians(_parameters.roll_limit));
@@ -626,6 +647,20 @@ FixedwingPositionControl::vehicle_airspeed_poll()
 	return airspeed_updated;
 }

+bool
+FixedwingPositionControl::range_finder_poll()
+{
+	/* check if there is a range finder measurement */
+	bool range_finder_updated;
+	orb_check(_range_finder_sub, &range_finder_updated);
+
+	if (range_finder_updated) {
+		orb_copy(ORB_ID(sensor_range_finder), _range_finder_sub, &_range_finder);
+	}
+
+	return range_finder_updated;
+}
+
 void
 FixedwingPositionControl::vehicle_attitude_poll()
 {
@@ -754,6 +789,23 @@ void FixedwingPositionControl::navigation_capabilities_publish()
 	}
 }

+float FixedwingPositionControl::get_relative_landingalt(float land_setpoint_alt, float current_alt, const struct range_finder_report &range_finder, float range_finder_use_relative_alt)
+{
+	float rel_alt_estimated = current_alt - land_setpoint_alt;
+
+	/* only use range finder if:
+	 * parameter (range_finder_use_relative_alt) > 0
+	 * the measurement is valid
+	 * the estimated relative altitude (from global altitude estimate and landing waypoint) <= range_finder_use_relative_alt
+	 */
+	if (range_finder_use_relative_alt < 0 || !range_finder.valid || rel_alt_estimated > range_finder_use_relative_alt ) {
+		return rel_alt_estimated;
+	}
+
+	return range_finder.distance;
+
+}
+
 bool
 FixedwingPositionControl::control_position(const math::Vector<2> &current_position, const math::Vector<2> &ground_speed,
 		const struct position_setpoint_triplet_s &pos_sp_triplet)
@@ -896,12 +948,14 @@ FixedwingPositionControl::control_position(const math::Vector<2> &current_positi

 			/* Calculate distance (to landing waypoint) and altitude of last ordinary waypoint L */
 			float L_wp_distance = get_distance_to_next_waypoint(prev_wp(0), prev_wp(1), curr_wp(0), curr_wp(1));
-			float L_altitude = landingslope.getLandingSlopeAbsoluteAltitude(L_wp_distance, _pos_sp_triplet.current.alt);
+			float L_altitude_rel = landingslope.getLandingSlopeRelativeAltitude(L_wp_distance);

 			float bearing_airplane_currwp = get_bearing_to_next_waypoint(current_position(0), current_position(1), curr_wp(0), curr_wp(1));
-			float landing_slope_alt_desired = landingslope.getLandingSlopeAbsoluteAltitudeSave(wp_distance, bearing_lastwp_currwp, bearing_airplane_currwp, _pos_sp_triplet.current.alt);
+			float landing_slope_alt_rel_desired = landingslope.getLandingSlopeRelativeAltitudeSave(wp_distance, bearing_lastwp_currwp, bearing_airplane_currwp);

-			if ( (_global_pos.alt < _pos_sp_triplet.current.alt + landingslope.flare_relative_alt()) || land_noreturn_vertical) {  //checking for land_noreturn to avoid unwanted climb out
+			float relative_alt = get_relative_landingalt(_pos_sp_triplet.current.alt, _global_pos.alt, _range_finder, _parameters.range_finder_rel_alt);
+
+			if ( (relative_alt < landingslope.flare_relative_alt()) || land_noreturn_vertical) {  //checking for land_noreturn to avoid unwanted climb out

 				/* land with minimal speed */

@@ -911,7 +965,7 @@ FixedwingPositionControl::control_position(const math::Vector<2> &current_positi
 				/* kill the throttle if param requests it */
 				throttle_max = _parameters.throttle_max;

-				 if (_global_pos.alt < _pos_sp_triplet.current.alt + landingslope.motor_lim_relative_alt() || land_motor_lim) {
+				 if (relative_alt < landingslope.motor_lim_relative_alt() || land_motor_lim) {
 					throttle_max = math::min(throttle_max, _parameters.throttle_land_max);
 					if (!land_motor_lim) {
 						land_motor_lim  = true;
@@ -920,16 +974,16 @@ FixedwingPositionControl::control_position(const math::Vector<2> &current_positi

 				 }

-				float flare_curve_alt = landingslope.getFlareCurveAltitudeSave(wp_distance, bearing_lastwp_currwp, bearing_airplane_currwp, _pos_sp_triplet.current.alt);
+				float flare_curve_alt_rel = landingslope.getFlareCurveRelativeAltitudeSave(wp_distance, bearing_lastwp_currwp, bearing_airplane_currwp);

 				/* avoid climbout */
-				if ((flare_curve_alt_last < flare_curve_alt && land_noreturn_vertical) || land_stayonground)
+				if ((flare_curve_alt_rel_last < flare_curve_alt_rel && land_noreturn_vertical) || land_stayonground)
 				{
-					flare_curve_alt = pos_sp_triplet.current.alt;
+					flare_curve_alt_rel = 0.0f; // stay on ground
 					land_stayonground = true;
 				}

-				_tecs.update_pitch_throttle(_R_nb, _att.pitch, _global_pos.alt, flare_curve_alt, calculate_target_airspeed(airspeed_land),
+				_tecs.update_pitch_throttle(_R_nb, _att.pitch, relative_alt, flare_curve_alt_rel, calculate_target_airspeed(airspeed_land),
 												    _airspeed.indicated_airspeed_m_s, eas2tas,
 												    false, flare_pitch_angle_rad,
 												    0.0f, throttle_max, throttle_land,
@@ -941,7 +995,7 @@ FixedwingPositionControl::control_position(const math::Vector<2> &current_positi
 				}
 				//warnx("Landing:  flare, _global_pos.alt  %.1f, flare_curve_alt %.1f, flare_curve_alt_last %.1f, flare_length %.1f, wp_distance %.1f", _global_pos.alt, flare_curve_alt, flare_curve_alt_last, flare_length, wp_distance);

-				flare_curve_alt_last = flare_curve_alt;
+				flare_curve_alt_rel_last = flare_curve_alt_rel;
 			} else {

 				 /* intersect glide slope:
@@ -949,20 +1003,20 @@ FixedwingPositionControl::control_position(const math::Vector<2> &current_positi
 				  * if current position is higher or within 10m of slope follow the glide slope
 				  * if current position is below slope -10m continue on maximum of previous wp altitude or L_altitude until the intersection with the slope
 				  * */
-				float altitude_desired = _global_pos.alt;
-				if (_global_pos.alt > landing_slope_alt_desired - 10.0f) {
+				float altitude_desired_rel = relative_alt;
+				if (relative_alt > landing_slope_alt_rel_desired - 10.0f) {
 					/* stay on slope */
-					altitude_desired = landing_slope_alt_desired;
+					altitude_desired_rel = landing_slope_alt_rel_desired;
 					if (!land_onslope) {
 						mavlink_log_info(_mavlink_fd, "#audio: Landing, on slope");
 						land_onslope = true;
 					}
 				} else {
 					/* continue horizontally */
-					altitude_desired =  math::max(_global_pos.alt, L_altitude);
+					altitude_desired_rel =  math::max(relative_alt, L_altitude_rel);
 				}

-				_tecs.update_pitch_throttle(_R_nb, _att.pitch, _global_pos.alt, altitude_desired, calculate_target_airspeed(airspeed_approach),
+				_tecs.update_pitch_throttle(_R_nb, _att.pitch, relative_alt, altitude_desired_rel, calculate_target_airspeed(airspeed_approach),
 							    _airspeed.indicated_airspeed_m_s, eas2tas,
 							    false, math::radians(_parameters.pitch_limit_min),
 							    _parameters.throttle_min, _parameters.throttle_max, _parameters.throttle_cruise,
@@ -1185,6 +1239,7 @@ FixedwingPositionControl::task_main()
 	_airspeed_sub = orb_subscribe(ORB_ID(airspeed));
 	_params_sub = orb_subscribe(ORB_ID(parameter_update));
 	_manual_control_sub = orb_subscribe(ORB_ID(manual_control_setpoint));
+	_range_finder_sub = orb_subscribe(ORB_ID(sensor_range_finder));

 	/* rate limit vehicle status updates to 5Hz */
 	orb_set_interval(_control_mode_sub, 200);
@@ -1264,6 +1319,7 @@ FixedwingPositionControl::task_main()
 			vehicle_setpoint_poll();
 			vehicle_sensor_combined_poll();
 			vehicle_airspeed_poll();
+			range_finder_poll();
 			// vehicle_baro_poll();

 			math::Vector<2> ground_speed(_global_pos.vel_n, _global_pos.vel_e);
@@ -375,3 +375,13 @@ PARAM_DEFINE_FLOAT(FW_LND_TLALT, 5.0f);
 * @group L1 Control
 */
 PARAM_DEFINE_FLOAT(FW_LND_HHDIST, 15.0f);
+
+/**
+ * Landing relative altitude threshold for range finder measurements
+ *
+ * range finder measurements will only be used below FW_LND_RFRALT estimated relative altitude (gobal_pos.alt - landing_waypoint.alt)
+ * set to -1 to disable
+ *
+ * @group L1 Control
+ */
+PARAM_DEFINE_FLOAT(FW_LND_RFRALT, 30.0f);
@@ -69,26 +69,46 @@ void Landingslope::calculateSlopeValues()
 	_horizontal_slope_displacement = (_flare_length - _d1);
 }

-float Landingslope::getLandingSlopeAbsoluteAltitude(float wp_distance, float wp_altitude)
+float  Landingslope::getLandingSlopeRelativeAltitude(float wp_landing_distance)
 {
-	return Landingslope::getLandingSlopeAbsoluteAltitude(wp_distance, wp_altitude, _horizontal_slope_displacement, _landing_slope_angle_rad);
+	return Landingslope::getLandingSlopeRelativeAltitude(wp_landing_distance, _horizontal_slope_displacement, _landing_slope_angle_rad);
 }

-float Landingslope::getLandingSlopeAbsoluteAltitudeSave(float wp_distance, float bearing_lastwp_currwp, float bearing_airplane_currwp, float wp_altitude)
+float Landingslope::getLandingSlopeRelativeAltitudeSave(float wp_landing_distance, float bearing_lastwp_currwp, float bearing_airplane_currwp)
 {
 	/* If airplane is in front of waypoint return slope altitude, else return waypoint altitude */
 	if (fabsf(bearing_airplane_currwp - bearing_lastwp_currwp) < math::radians(90.0f))
-		return getLandingSlopeAbsoluteAltitude(wp_distance, wp_altitude);
+		return getLandingSlopeRelativeAltitude(wp_landing_distance);
+	else
+		return 0.0f;
+}
+
+float Landingslope::getLandingSlopeAbsoluteAltitude(float wp_landing_distance, float wp_altitude)
+{
+	return Landingslope::getLandingSlopeAbsoluteAltitude(wp_landing_distance, wp_altitude, _horizontal_slope_displacement, _landing_slope_angle_rad);
+}
+
+float Landingslope::getLandingSlopeAbsoluteAltitudeSave(float wp_landing_distance, float bearing_lastwp_currwp, float bearing_airplane_currwp, float wp_altitude)
+{
+	/* If airplane is in front of waypoint return slope altitude, else return waypoint altitude */
+	if (fabsf(bearing_airplane_currwp - bearing_lastwp_currwp) < math::radians(90.0f))
+		return getLandingSlopeAbsoluteAltitude(wp_landing_distance, wp_altitude);
 	else
 		return wp_altitude;
 }

-float Landingslope::getFlareCurveAltitudeSave(float wp_landing_distance, float bearing_lastwp_currwp, float bearing_airplane_currwp, float wp_landing_altitude)
+float Landingslope::getFlareCurveRelativeAltitudeSave(float wp_landing_distance, float bearing_lastwp_currwp, float bearing_airplane_currwp)
 {
 	/* If airplane is in front of waypoint return flare curve altitude, else return waypoint altitude */
 	if (fabsf(bearing_airplane_currwp - bearing_lastwp_currwp) < math::radians(90.0f))
-		return wp_landing_altitude + _H0 * expf(-math::max(0.0f, _flare_length - wp_landing_distance)/_flare_constant) - _H1_virt;
+		return _H0 * expf(-math::max(0.0f, _flare_length - wp_landing_distance)/_flare_constant) - _H1_virt;
 	else
-		return wp_landing_altitude;
+		return 0.0f;
+}
+
+float Landingslope::getFlareCurveAbsoluteAltitudeSave(float wp_landing_distance, float bearing_lastwp_currwp, float bearing_airplane_currwp, float wp_landing_altitude)
+{
+
+	return wp_landing_altitude + getFlareCurveRelativeAltitudeSave(wp_landing_distance, bearing_lastwp_currwp, bearing_airplane_currwp);
 }

@@ -63,11 +63,26 @@ 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_distance, float wp_altitude);
+	float getLandingSlopeAbsoluteAltitude(float wp_landing_distance, float wp_altitude);

 	/**
 	 *
@@ -76,13 +91,22 @@ public:
 	 */
 	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 (wp_landing_distance - horizontal_slope_displacement) * tanf(landing_slope_angle_rad) + wp_landing_altitude; //flare_relative_alt is negative
+		return getLandingSlopeRelativeAltitude(wp_landing_distance, horizontal_slope_displacement, landing_slope_angle_rad) + wp_landing_altitude;
 	}

 	/**
@@ -95,8 +119,9 @@ public:

 	}

+	float getFlareCurveRelativeAltitudeSave(float wp_distance, float bearing_lastwp_currwp, float bearing_airplane_currwp);

-	float getFlareCurveAltitudeSave(float wp_distance, float bearing_lastwp_currwp, float bearing_airplane_currwp, float wp_altitude);
+	float getFlareCurveAbsoluteAltitudeSave(float wp_distance, float bearing_lastwp_currwp, float bearing_airplane_currwp, float wp_altitude);

 	void update(float landing_slope_angle_rad,
 			float flare_relative_alt,