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

@@ -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
  *