add heightrate ff for tecs

src/lib/external_lgpl/tecs/tecs.cpp

@@ -238,7 +238,7 @@ void TECS::_update_height_demand(float demand, float state)
 	_hgt_dem_adj = demand;//0.025f * demand + 0.975f * _hgt_dem_adj_last;
 	_hgt_dem_adj_last = _hgt_dem_adj;
 
-	_hgt_rate_dem = (_hgt_dem_adj-state)*_heightrate_p;
+	_hgt_rate_dem = (_hgt_dem_adj-state)*_heightrate_p + _heightrate_ff * (_hgt_dem_adj - _hgt_dem_adj_last)/_DT;
 	// Limit height rate of change
 	if (_hgt_rate_dem > _maxClimbRate) {
 		_hgt_rate_dem = _maxClimbRate;

src/lib/external_lgpl/tecs/tecs.h

@@ -47,6 +47,7 @@ public:
 		_rollComp(0.0f),
 		_spdWeight(0.5f),
 		_heightrate_p(0.0f),
+		_heightrate_ff(0.0f),
 		_speedrate_p(0.0f),
 		_throttle_dem(0.0f),
 		_pitch_dem(0.0f),
@@ -220,6 +221,10 @@ public:
 		_heightrate_p = heightrate_p;
 	}
 
+	void set_heightrate_ff(float heightrate_ff) {
+		_heightrate_ff = heightrate_ff;
+	}
+
 	void set_speedrate_p(float speedrate_p) {
 		_speedrate_p = speedrate_p;
 	}
@@ -256,6 +261,7 @@ private:
 	float _rollComp;
 	float _spdWeight;
 	float _heightrate_p;
+	float _heightrate_ff;
 	float _speedrate_p;
 
 	// throttle demand in the range from 0.0 to 1.0

src/modules/fw_pos_control_l1/fw_pos_control_l1_main.cpp

@@ -211,6 +211,7 @@ private:
 		float max_climb_rate;
 		float climbout_diff;
 		float heightrate_p;
+		float heightrate_ff;
 		float speedrate_p;
 		float throttle_damp;
 		float integrator_gain;
@@ -256,6 +257,7 @@ private:
 		param_t max_climb_rate;
 		param_t climbout_diff;
 		param_t heightrate_p;
+		param_t heightrate_ff;
 		param_t speedrate_p;
 		param_t throttle_damp;
 		param_t integrator_gain;
@@ -494,6 +496,7 @@ FixedwingPositionControl::FixedwingPositionControl() :
 	_parameter_handles.speed_weight = 			param_find("FW_T_SPDWEIGHT");
 	_parameter_handles.pitch_damping = 			param_find("FW_T_PTCH_DAMP");
 	_parameter_handles.heightrate_p =			param_find("FW_T_HRATE_P");
+	_parameter_handles.heightrate_ff =			param_find("FW_T_HRATE_FF");
 	_parameter_handles.speedrate_p =			param_find("FW_T_SRATE_P");
 
 	/* fetch initial parameter values */
@@ -563,6 +566,7 @@ FixedwingPositionControl::parameters_update()
 	param_get(_parameter_handles.climbout_diff, &(_parameters.climbout_diff));
 
 	param_get(_parameter_handles.heightrate_p, &(_parameters.heightrate_p));
+	param_get(_parameter_handles.heightrate_ff, &(_parameters.heightrate_ff));
 	param_get(_parameter_handles.speedrate_p, &(_parameters.speedrate_p));
 
 	param_get(_parameter_handles.land_slope_angle, &(_parameters.land_slope_angle));
@@ -600,6 +604,7 @@ FixedwingPositionControl::parameters_update()
 	_tecs.set_indicated_airspeed_max(_parameters.airspeed_max);
 	_tecs.set_max_climb_rate(_parameters.max_climb_rate);
 	_tecs.set_heightrate_p(_parameters.heightrate_p);
+	_tecs.set_heightrate_ff(_parameters.heightrate_ff);
 	_tecs.set_speedrate_p(_parameters.speedrate_p);
 
 	/* sanity check parameters */

src/modules/fw_pos_control_l1/fw_pos_control_l1_params.c

@@ -131,8 +131,8 @@ PARAM_DEFINE_FLOAT(FW_R_LIM, 45.0f);
 /**
  * Throttle limit max
  *
- * This is the maximum throttle % that can be used by the controller. 
- * For overpowered aircraft, this should be reduced to a value that 
+ * This is the maximum throttle % that can be used by the controller.
+ * For overpowered aircraft, this should be reduced to a value that
  * provides sufficient thrust to climb at the maximum pitch angle PTCH_MAX.
  *
  * @group L1 Control
@@ -142,10 +142,10 @@ PARAM_DEFINE_FLOAT(FW_THR_MAX, 1.0f);
 /**
  * Throttle limit min
  *
- * This is the minimum throttle % that can be used by the controller. 
- * For electric aircraft this will normally be set to zero, but can be set 
- * to a small non-zero value if a folding prop is fitted to prevent the 
- * prop from folding and unfolding repeatedly in-flight or to provide 
+ * This is the minimum throttle % that can be used by the controller.
+ * For electric aircraft this will normally be set to zero, but can be set
+ * to a small non-zero value if a folding prop is fitted to prevent the
+ * prop from folding and unfolding repeatedly in-flight or to provide
  * some aerodynamic drag from a turning prop to improve the descent rate.
  *
  * For aircraft with internal combustion engine this parameter should be set
@@ -158,7 +158,7 @@ PARAM_DEFINE_FLOAT(FW_THR_MIN, 0.0f);
 /**
  * Throttle limit value before flare
  *
- * This throttle value will be set as throttle limit at FW_LND_TLALT, 
+ * This throttle value will be set as throttle limit at FW_LND_TLALT,
  * before arcraft will flare.
  *
  * @group L1 Control
@@ -180,17 +180,17 @@ PARAM_DEFINE_FLOAT(FW_CLMBOUT_DIFF, 25.0f);
 /**
  * Maximum climb rate
  *
- * This is the best climb rate that the aircraft can achieve with 
- * the throttle set to THR_MAX and the airspeed set to the 
- * default value. For electric aircraft make sure this number can be 
- * achieved towards the end of flight when the battery voltage has reduced. 
- * The setting of this parameter can be checked by commanding a positive 
- * altitude change of 100m in loiter, RTL or guided mode. If the throttle 
- * required to climb is close to THR_MAX and the aircraft is maintaining 
- * airspeed, then this parameter is set correctly. If the airspeed starts 
- * to reduce, then the parameter is set to high, and if the throttle 
- * demand required to climb and maintain speed is noticeably less than 
- * FW_THR_MAX, then either FW_T_CLMB_MAX should be increased or 
+ * This is the best climb rate that the aircraft can achieve with
+ * the throttle set to THR_MAX and the airspeed set to the
+ * default value. For electric aircraft make sure this number can be
+ * achieved towards the end of flight when the battery voltage has reduced.
+ * The setting of this parameter can be checked by commanding a positive
+ * altitude change of 100m in loiter, RTL or guided mode. If the throttle
+ * required to climb is close to THR_MAX and the aircraft is maintaining
+ * airspeed, then this parameter is set correctly. If the airspeed starts
+ * to reduce, then the parameter is set to high, and if the throttle
+ * demand required to climb and maintain speed is noticeably less than
+ * FW_THR_MAX, then either FW_T_CLMB_MAX should be increased or
  * FW_THR_MAX reduced.
  *
  * @group L1 Control
@@ -200,8 +200,8 @@ PARAM_DEFINE_FLOAT(FW_T_CLMB_MAX, 5.0f);
 /**
  * Minimum descent rate
  *
- * This is the sink rate of the aircraft with the throttle 
- * set to THR_MIN and flown at the same airspeed as used 
+ * This is the sink rate of the aircraft with the throttle
+ * set to THR_MIN and flown at the same airspeed as used
  * to measure FW_T_CLMB_MAX.
  *
  * @group Fixed Wing TECS
@@ -211,10 +211,10 @@ PARAM_DEFINE_FLOAT(FW_T_SINK_MIN, 2.0f);
 /**
  * Maximum descent rate
  *
- * This sets the maximum descent rate that the controller will use. 
- * If this value is too large, the aircraft can over-speed on descent. 
- * This should be set to a value that can be achieved without 
- * exceeding the lower pitch angle limit and without over-speeding 
+ * This sets the maximum descent rate that the controller will use.
+ * If this value is too large, the aircraft can over-speed on descent.
+ * This should be set to a value that can be achieved without
+ * exceeding the lower pitch angle limit and without over-speeding
  * the aircraft.
  *
  * @group Fixed Wing TECS
@@ -224,7 +224,7 @@ PARAM_DEFINE_FLOAT(FW_T_SINK_MAX, 5.0f);
 /**
  * TECS time constant
  *
- * This is the time constant of the TECS control algorithm (in seconds). 
+ * This is the time constant of the TECS control algorithm (in seconds).
  * Smaller values make it faster to respond, larger values make it slower
  * to respond.
  *
@@ -235,7 +235,7 @@ 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). 
+ * 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.
  *
@@ -246,7 +246,7 @@ PARAM_DEFINE_FLOAT(FW_T_THRO_CONST, 8.0f);
 /**
  * Throttle damping factor
  *
- * This is the damping gain for the throttle demand loop. 
+ * This is the damping gain for the throttle demand loop.
  * Increase to add damping to correct for oscillations in speed and height.
  *
  * @group Fixed Wing TECS
@@ -256,9 +256,9 @@ PARAM_DEFINE_FLOAT(FW_T_THR_DAMP, 0.5f);
 /**
  * Integrator gain
  *
- * This is the integrator gain on the control loop. 
- * Increasing this gain increases the speed at which speed 
- * and height offsets are trimmed out, but reduces damping and 
+ * This is the integrator gain on the control loop.
+ * Increasing this gain increases the speed at which speed
+ * and height offsets are trimmed out, but reduces damping and
  * increases overshoot.
  *
  * @group Fixed Wing TECS
@@ -269,9 +269,9 @@ PARAM_DEFINE_FLOAT(FW_T_INTEG_GAIN, 0.1f);
  * Maximum vertical acceleration
  *
  * This is the maximum vertical acceleration (in metres/second square)
- * either up or down that the controller will use to correct speed 
- * or height errors. The default value of 7 m/s/s (equivalent to +- 0.7 g) 
- * allows for reasonably aggressive pitch changes if required to recover 
+ * either up or down that the controller will use to correct speed
+ * or height errors. The default value of 7 m/s/s (equivalent to +- 0.7 g)
+ * allows for reasonably aggressive pitch changes if required to recover
  * from under-speed conditions.
  *
  * @group Fixed Wing TECS
@@ -281,10 +281,10 @@ PARAM_DEFINE_FLOAT(FW_T_VERT_ACC, 7.0f);
 /**
  * Complementary filter "omega" parameter for height
  *
- * This is the cross-over frequency (in radians/second) of the complementary 
- * filter used to fuse vertical acceleration and barometric height to obtain 
- * an estimate of height rate and height. Increasing this frequency weights 
- * the solution more towards use of the barometer, whilst reducing it weights 
+ * This is the cross-over frequency (in radians/second) of the complementary
+ * filter used to fuse vertical acceleration and barometric height to obtain
+ * an estimate of height rate and height. Increasing this frequency weights
+ * the solution more towards use of the barometer, whilst reducing it weights
  * the solution more towards use of the accelerometer data.
  *
  * @group Fixed Wing TECS
@@ -294,10 +294,10 @@ PARAM_DEFINE_FLOAT(FW_T_HGT_OMEGA, 3.0f);
 /**
  * Complementary filter "omega" parameter for speed
  *
- * This is the cross-over frequency (in radians/second) of the complementary 
- * filter used to fuse longitudinal acceleration and airspeed to obtain an 
+ * This is the cross-over frequency (in radians/second) of the complementary
+ * filter used to fuse longitudinal acceleration and airspeed to obtain an
  * improved airspeed estimate. Increasing this frequency weights the solution
- * more towards use of the arispeed sensor, whilst reducing it weights the 
+ * more towards use of the arispeed sensor, whilst reducing it weights the
  * solution more towards use of the accelerometer data.
  *
  * @group Fixed Wing TECS
@@ -307,13 +307,13 @@ PARAM_DEFINE_FLOAT(FW_T_SPD_OMEGA, 2.0f);
 /**
  * Roll -> Throttle feedforward
  *
- * Increasing this gain turn increases the amount of throttle that will 
- * be used to compensate for the additional drag created by turning. 
- * Ideally this should be set to  approximately 10 x the extra sink rate 
- * in m/s created by a 45 degree bank turn. Increase this gain if 
- * the aircraft initially loses energy in turns and reduce if the 
- * aircraft initially gains energy in turns. Efficient high aspect-ratio 
- * aircraft (eg powered sailplanes) can use a lower value, whereas 
+ * Increasing this gain turn increases the amount of throttle that will
+ * be used to compensate for the additional drag created by turning.
+ * Ideally this should be set to  approximately 10 x the extra sink rate
+ * in m/s created by a 45 degree bank turn. Increase this gain if
+ * the aircraft initially loses energy in turns and reduce if the
+ * aircraft initially gains energy in turns. Efficient high aspect-ratio
+ * aircraft (eg powered sailplanes) can use a lower value, whereas
  * inefficient low aspect-ratio models (eg delta wings) can use a higher value.
  *
  * @group Fixed Wing TECS
@@ -323,15 +323,15 @@ PARAM_DEFINE_FLOAT(FW_T_RLL2THR, 10.0f);
 /**
  * Speed <--> Altitude priority
  *
- * This parameter adjusts the amount of weighting that the pitch control 
- * applies to speed vs height errors. Setting it to 0.0 will cause the 
- * pitch control to control height and ignore speed errors. This will 
- * normally improve height accuracy but give larger airspeed errors. 
- * Setting it to 2.0 will cause the pitch control loop to control speed 
- * and ignore height errors. This will normally reduce airspeed errors, 
- * but give larger height errors. The default value of 1.0 allows the pitch 
- * control to simultaneously control height and speed. 
- * Note to Glider Pilots - set this parameter to 2.0 (The glider will 
+ * This parameter adjusts the amount of weighting that the pitch control
+ * applies to speed vs height errors. Setting it to 0.0 will cause the
+ * pitch control to control height and ignore speed errors. This will
+ * normally improve height accuracy but give larger airspeed errors.
+ * Setting it to 2.0 will cause the pitch control loop to control speed
+ * and ignore height errors. This will normally reduce airspeed errors,
+ * but give larger height errors. The default value of 1.0 allows the pitch
+ * control to simultaneously control height and speed.
+ * 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 Fixed Wing TECS
@@ -341,9 +341,9 @@ PARAM_DEFINE_FLOAT(FW_T_SPDWEIGHT, 1.0f);
 /**
  * Pitch damping factor
  *
- * This is the damping gain for the pitch demand loop. Increase to add 
- * damping to correct for oscillations in height. The default value of 0.0 
- * will work well provided the pitch to servo controller has been tuned 
+ * This is the damping gain for the pitch demand loop. Increase to add
+ * damping to correct for oscillations in height. The default value of 0.0
+ * will work well provided the pitch to servo controller has been tuned
  * properly.
  *
  * @group Fixed Wing TECS
@@ -357,6 +357,13 @@ PARAM_DEFINE_FLOAT(FW_T_PTCH_DAMP, 0.0f);
  */
 PARAM_DEFINE_FLOAT(FW_T_HRATE_P, 0.05f);
 
+/**
+ * Height rate FF factor
+ *
+ * @group Fixed Wing TECS
+ */
+PARAM_DEFINE_FLOAT(FW_T_HRATE_FF, 0.0f);
+
 /**
  * Speed rate P factor
  *