Merge pull request #1250 from PX4/throttle_tuning

Throttle tuning

src/lib/external_lgpl/tecs/tecs.cpp

@@ -298,7 +298,7 @@ void TECS::_update_throttle(float throttle_cruise, const math::Matrix<3,3> &rotM
 
 	} else {
 		// Calculate gain scaler from specific energy error to throttle
-		float K_STE2Thr = 1 / (_timeConst * (_STEdot_max - _STEdot_min));
+		float K_STE2Thr = 1 / (_timeConstThrot * (_STEdot_max - _STEdot_min));
 
 		// Calculate feed-forward throttle
 		float ff_throttle = 0;
@@ -327,9 +327,12 @@ void TECS::_update_throttle(float throttle_cruise, const math::Matrix<3,3> &rotM
 			_throttle_dem = constrain(_throttle_dem,
 						  _last_throttle_dem - thrRateIncr,
 						  _last_throttle_dem + thrRateIncr);
-			_last_throttle_dem = _throttle_dem;
 		}
 
+		// Ensure _last_throttle_dem is always initialized properly
+		// Also: The throttle_slewrate limit is only applied to throttle_dem, but does not limit the integrator!!
+		_last_throttle_dem = _throttle_dem;
+
 
 		// Calculate integrator state upper and lower limits
 		// Set to a value thqat will allow 0.1 (10%) throttle saturation to allow for noise on the demand

src/lib/external_lgpl/tecs/tecs.h

@@ -28,6 +28,26 @@ class __EXPORT TECS
 {
 public:
 	TECS() :
+		_update_50hz_last_usec(0),
+		_update_speed_last_usec(0),
+		_update_pitch_throttle_last_usec(0),
+		// TECS tuning parameters
+		_hgtCompFiltOmega(0.0f),
+		_spdCompFiltOmega(0.0f),
+		_maxClimbRate(2.0f),
+		_minSinkRate(1.0f),
+		_maxSinkRate(2.0f),
+		_timeConst(5.0f),
+		_timeConstThrot(8.0f),
+		_ptchDamp(0.0f),
+		_thrDamp(0.0f),
+		_integGain(0.0f),
+		_vertAccLim(0.0f),
+		_rollComp(0.0f),
+		_spdWeight(0.5f),
+		_heightrate_p(0.0f),
+		_speedrate_p(0.0f),
+		_throttle_dem(0.0f),
 		_pitch_dem(0.0f),
 		_integ1_state(0.0f),
 		_integ2_state(0.0f),
@@ -123,6 +143,10 @@ public:
 		_timeConst = time_const;
 	}
 
+	void set_time_const_throt(float time_const_throt) {
+		_timeConstThrot = time_const_throt;
+	}
+
 	void set_min_sink_rate(float rate) {
 		_minSinkRate = rate;
 	}
@@ -204,6 +228,7 @@ private:
 	float _minSinkRate;
 	float _maxSinkRate;
 	float _timeConst;
+	float _timeConstThrot;
 	float _ptchDamp;
 	float _thrDamp;
 	float _integGain;

src/modules/fw_pos_control_l1/fw_pos_control_l1_main.cpp

@@ -203,9 +203,11 @@ private:
 		float l1_damping;
 
 		float time_const;
+		float time_const_throt;
 		float min_sink_rate;
 		float max_sink_rate;
 		float max_climb_rate;
+		float climbout_diff;
 		float heightrate_p;
 		float speedrate_p;
 		float throttle_damp;
@@ -227,6 +229,7 @@ private:
 		float throttle_min;
 		float throttle_max;
 		float throttle_cruise;
+		float throttle_slew_max;
 
 		float throttle_land_max;
 
@@ -245,9 +248,11 @@ private:
 		param_t l1_damping;
 
 		param_t time_const;
+		param_t time_const_throt;
 		param_t min_sink_rate;
 		param_t max_sink_rate;
 		param_t max_climb_rate;
+		param_t climbout_diff;
 		param_t heightrate_p;
 		param_t speedrate_p;
 		param_t throttle_damp;
@@ -269,6 +274,7 @@ private:
 		param_t throttle_min;
 		param_t throttle_max;
 		param_t throttle_cruise;
+		param_t throttle_slew_max;
 
 		param_t throttle_land_max;
 
@@ -460,6 +466,7 @@ FixedwingPositionControl::FixedwingPositionControl() :
 	_parameter_handles.roll_limit = param_find("FW_R_LIM");
 	_parameter_handles.throttle_min = param_find("FW_THR_MIN");
 	_parameter_handles.throttle_max = param_find("FW_THR_MAX");
+	_parameter_handles.throttle_slew_max = param_find("FW_THR_SLEW_MAX");
 	_parameter_handles.throttle_cruise = param_find("FW_THR_CRUISE");
 	_parameter_handles.throttle_land_max = param_find("FW_THR_LND_MAX");
 
@@ -471,9 +478,11 @@ FixedwingPositionControl::FixedwingPositionControl() :
 	_parameter_handles.range_finder_rel_alt = param_find("FW_LND_RFRALT");
 
 	_parameter_handles.time_const = 			param_find("FW_T_TIME_CONST");
+	_parameter_handles.time_const_throt = 			param_find("FW_T_THRO_CONST");
 	_parameter_handles.min_sink_rate = 			param_find("FW_T_SINK_MIN");
 	_parameter_handles.max_sink_rate =			param_find("FW_T_SINK_MAX");
 	_parameter_handles.max_climb_rate =			param_find("FW_T_CLMB_MAX");
+	_parameter_handles.climbout_diff =			param_find("FW_CLMBOUT_DIFF");
 	_parameter_handles.throttle_damp = 			param_find("FW_T_THR_DAMP");
 	_parameter_handles.integrator_gain =			param_find("FW_T_INTEG_GAIN");
 	_parameter_handles.vertical_accel_limit =		param_find("FW_T_VERT_ACC");
@@ -532,10 +541,12 @@ FixedwingPositionControl::parameters_update()
 	param_get(_parameter_handles.throttle_min, &(_parameters.throttle_min));
 	param_get(_parameter_handles.throttle_max, &(_parameters.throttle_max));
 	param_get(_parameter_handles.throttle_cruise, &(_parameters.throttle_cruise));
+	param_get(_parameter_handles.throttle_slew_max, &(_parameters.throttle_slew_max));
 
 	param_get(_parameter_handles.throttle_land_max, &(_parameters.throttle_land_max));
 
 	param_get(_parameter_handles.time_const, &(_parameters.time_const));
+	param_get(_parameter_handles.time_const_throt, &(_parameters.time_const_throt));
 	param_get(_parameter_handles.min_sink_rate, &(_parameters.min_sink_rate));
 	param_get(_parameter_handles.max_sink_rate, &(_parameters.max_sink_rate));
 	param_get(_parameter_handles.throttle_damp, &(_parameters.throttle_damp));
@@ -547,6 +558,7 @@ FixedwingPositionControl::parameters_update()
 	param_get(_parameter_handles.speed_weight, &(_parameters.speed_weight));
 	param_get(_parameter_handles.pitch_damping, &(_parameters.pitch_damping));
 	param_get(_parameter_handles.max_climb_rate, &(_parameters.max_climb_rate));
+	param_get(_parameter_handles.climbout_diff, &(_parameters.climbout_diff));
 
 	param_get(_parameter_handles.heightrate_p, &(_parameters.heightrate_p));
 	param_get(_parameter_handles.speedrate_p, &(_parameters.speedrate_p));
@@ -564,9 +576,11 @@ FixedwingPositionControl::parameters_update()
 	_l1_control.set_l1_roll_limit(math::radians(_parameters.roll_limit));
 
 	_tecs.set_time_const(_parameters.time_const);
+	_tecs.set_time_const_throt(_parameters.time_const_throt);
 	_tecs.set_min_sink_rate(_parameters.min_sink_rate);
 	_tecs.set_max_sink_rate(_parameters.max_sink_rate);
 	_tecs.set_throttle_damp(_parameters.throttle_damp);
+	_tecs.set_throttle_slewrate(_parameters.throttle_slew_max);
 	_tecs.set_integrator_gain(_parameters.integrator_gain);
 	_tecs.set_vertical_accel_limit(_parameters.vertical_accel_limit);
 	_tecs.set_height_comp_filter_omega(_parameters.height_comp_filter_omega);
@@ -1095,7 +1109,7 @@ FixedwingPositionControl::control_position(const math::Vector<2> &current_positi
 				usePreTakeoffThrust = false;
 
 				/* apply minimum pitch and limit roll if target altitude is not within 10 meters */
-				if (altitude_error > 15.0f) {
+				if (_parameters.climbout_diff > 0.001f && altitude_error > _parameters.climbout_diff) {
 
 					/* enforce a minimum of 10 degrees pitch up on takeoff, or take parameter */
 					tecs_update_pitch_throttle(_pos_sp_triplet.current.alt,

src/modules/fw_pos_control_l1/fw_pos_control_l1_params.c

@@ -82,6 +82,17 @@ PARAM_DEFINE_FLOAT(FW_L1_DAMPING, 0.75f);
  */
 PARAM_DEFINE_FLOAT(FW_THR_CRUISE, 0.7f);
 
+/**
+ * Throttle max slew rate
+ *
+ * Maximum slew rate for the commanded throttle
+ *
+ * @min 0.0
+ * @max 1.0
+ * @group L1 Control
+ */
+PARAM_DEFINE_FLOAT(FW_THR_SLEW_MAX, 0.0f);
+
 /**
  * Negative pitch limit
  *
@@ -154,6 +165,18 @@ PARAM_DEFINE_FLOAT(FW_THR_MIN, 0.0f);
  */
 PARAM_DEFINE_FLOAT(FW_THR_LND_MAX, 1.0f);
 
+/**
+ * Climbout Altitude difference
+ *
+ * If the altitude error exceeds this parameter, the system will climb out
+ * with maximum throttle and minimum airspeed until it is closer than this
+ * distance to the desired altitude. Mostly used for takeoff waypoints / modes.
+ * Set to zero to disable climbout mode (not recommended).
+ *
+ * @group L1 Control
+ */
+PARAM_DEFINE_FLOAT(FW_CLMBOUT_DIFF, 25.0f);
+
 /**
  * Maximum climb rate
  *
@@ -181,7 +204,7 @@ PARAM_DEFINE_FLOAT(FW_T_CLMB_MAX, 5.0f);
  * set to THR_MIN and flown at the same airspeed as used 
  * to measure FW_T_CLMB_MAX.
  *
- * @group L1 Control
+ * @group Fixed Wing TECS
  */
 PARAM_DEFINE_FLOAT(FW_T_SINK_MIN, 2.0f);
 
@@ -194,7 +217,7 @@ PARAM_DEFINE_FLOAT(FW_T_SINK_MIN, 2.0f);
  * exceeding the lower pitch angle limit and without over-speeding 
  * the aircraft.
  *
- * @group L1 Control
+ * @group Fixed Wing TECS
  */
 PARAM_DEFINE_FLOAT(FW_T_SINK_MAX, 5.0f);
 
@@ -205,17 +228,28 @@ PARAM_DEFINE_FLOAT(FW_T_SINK_MAX, 5.0f);
  * Smaller values make it faster to respond, larger values make it slower
  * to respond.
  *
- * @group L1 Control
+ * @group Fixed Wing TECS
  */
 PARAM_DEFINE_FLOAT(FW_T_TIME_CONST, 5.0f);
 
+/**
+ * TECS Throttle time constant
+ *
+ * This is the time constant of the TECS throttle control algorithm (in seconds). 
+ * Smaller values make it faster to respond, larger values make it slower
+ * to respond.
+ *
+ * @group Fixed Wing TECS
+ */
+PARAM_DEFINE_FLOAT(FW_T_THRO_CONST, 8.0f);
+
 /**
  * Throttle damping factor
  *
  * This is the damping gain for the throttle demand loop. 
  * Increase to add damping to correct for oscillations in speed and height.
  *
- * @group L1 Control
+ * @group Fixed Wing TECS
  */
 PARAM_DEFINE_FLOAT(FW_T_THR_DAMP, 0.5f);
 
@@ -227,7 +261,7 @@ PARAM_DEFINE_FLOAT(FW_T_THR_DAMP, 0.5f);
  * and height offsets are trimmed out, but reduces damping and 
  * increases overshoot.
  *
- * @group L1 Control
+ * @group Fixed Wing TECS
  */
 PARAM_DEFINE_FLOAT(FW_T_INTEG_GAIN, 0.1f);
 
@@ -240,7 +274,7 @@ PARAM_DEFINE_FLOAT(FW_T_INTEG_GAIN, 0.1f);
  * allows for reasonably aggressive pitch changes if required to recover 
  * from under-speed conditions.
  *
- * @group L1 Control
+ * @group Fixed Wing TECS
  */
 PARAM_DEFINE_FLOAT(FW_T_VERT_ACC, 7.0f);
 
@@ -253,7 +287,7 @@ PARAM_DEFINE_FLOAT(FW_T_VERT_ACC, 7.0f);
  * the solution more towards use of the barometer, whilst reducing it weights 
  * the solution more towards use of the accelerometer data.
  *
- * @group L1 Control
+ * @group Fixed Wing TECS
  */
 PARAM_DEFINE_FLOAT(FW_T_HGT_OMEGA, 3.0f);
 
@@ -266,7 +300,7 @@ PARAM_DEFINE_FLOAT(FW_T_HGT_OMEGA, 3.0f);
  * more towards use of the arispeed sensor, whilst reducing it weights the 
  * solution more towards use of the accelerometer data.
  *
- * @group L1 Control
+ * @group Fixed Wing TECS
  */
 PARAM_DEFINE_FLOAT(FW_T_SPD_OMEGA, 2.0f);
 
@@ -282,7 +316,7 @@ PARAM_DEFINE_FLOAT(FW_T_SPD_OMEGA, 2.0f);
  * aircraft (eg powered sailplanes) can use a lower value, whereas 
  * inefficient low aspect-ratio models (eg delta wings) can use a higher value.
  *
- * @group L1 Control
+ * @group Fixed Wing TECS
  */
 PARAM_DEFINE_FLOAT(FW_T_RLL2THR, 10.0f);
 
@@ -300,7 +334,7 @@ PARAM_DEFINE_FLOAT(FW_T_RLL2THR, 10.0f);
  * Note to Glider Pilots - set this parameter to 2.0 (The glider will 
  * adjust its pitch angle to maintain airspeed, ignoring changes in height).
  *
- * @group L1 Control
+ * @group Fixed Wing TECS
  */
 PARAM_DEFINE_FLOAT(FW_T_SPDWEIGHT, 1.0f);
 
@@ -312,21 +346,21 @@ PARAM_DEFINE_FLOAT(FW_T_SPDWEIGHT, 1.0f);
  * will work well provided the pitch to servo controller has been tuned 
  * properly.
  *
- * @group L1 Control
+ * @group Fixed Wing TECS
  */
 PARAM_DEFINE_FLOAT(FW_T_PTCH_DAMP, 0.0f);
 
 /**
  * Height rate P factor
  *
- * @group L1 Control
+ * @group Fixed Wing TECS
  */
 PARAM_DEFINE_FLOAT(FW_T_HRATE_P, 0.05f);
 
 /**
  * Speed rate P factor
  *
- * @group L1 Control
+ * @group Fixed Wing TECS
  */
 PARAM_DEFINE_FLOAT(FW_T_SRATE_P, 0.05f);
 

src/modules/fw_pos_control_l1/mtecs/mTecs.cpp

@@ -76,7 +76,6 @@ mTecs::mTecs() :
 	_counter(0),
 	_debug(false)
 {
-	warnx("starting");
 }
 
 mTecs::~mTecs()