Add yaw time constant

src/modules/fw_att_control/FixedwingAttitudeControl.cpp

@@ -100,6 +100,7 @@ FixedwingAttitudeControl::parameters_update()
 	_roll_ctrl.set_integrator_max(_param_fw_rr_imax.get());
 
 	/* yaw control parameters */
+	_yaw_ctrl.set_time_constant(_param_fw_y_tc.get());
 	_yaw_ctrl.set_k_p(_param_fw_yr_p.get());
 	_yaw_ctrl.set_k_i(_param_fw_yr_i.get());
 	_yaw_ctrl.set_k_ff(_param_fw_yr_ff.get());

src/modules/fw_att_control/FixedwingAttitudeControl.hpp

@@ -200,6 +200,7 @@ private:
 		(ParamFloat<px4::params::FW_WR_P>) _param_fw_wr_p,
 
 		(ParamFloat<px4::params::FW_Y_RMAX>) _param_fw_y_rmax,
+		(ParamFloat<px4::params::FW_Y_TC>) _param_fw_y_tc,
 		(ParamFloat<px4::params::FW_YR_FF>) _param_fw_yr_ff,
 		(ParamFloat<px4::params::FW_YR_I>) _param_fw_yr_i,
 		(ParamFloat<px4::params::FW_YR_IMAX>) _param_fw_yr_imax,

src/modules/fw_att_control/ecl_yaw_controller.cpp

@@ -47,9 +47,7 @@ float ECL_YawController::control_attitude(const float dt, const ECL_ControlData
 {
 	/* Do not calculate control signal with bad inputs */
 	if (!(PX4_ISFINITE(ctl_data.roll) &&
-	      PX4_ISFINITE(ctl_data.pitch) &&
-	      PX4_ISFINITE(ctl_data.roll_rate_setpoint) &&
-	      PX4_ISFINITE(ctl_data.pitch_rate_setpoint))) {
+	      PX4_ISFINITE(ctl_data.pitch))) {
 
 		return _rate_setpoint;
 	}

src/modules/fw_att_control/fw_att_control_params.c

@@ -272,6 +272,24 @@ PARAM_DEFINE_FLOAT(FW_YR_IMAX, 0.2f);
  */
 PARAM_DEFINE_FLOAT(FW_Y_RMAX, 50.0f);
 
+/**
+ * Attitude yaw time constant
+ *
+ * This defines the latency between a yaw step input and the achieved setpoint
+ * (inverse to a P gain). Half a second is a good start value and fits for
+ * most average systems. Smaller systems may require smaller values, but as
+ * this will wear out servos faster, the value should only be decreased as
+ * needed.
+ *
+ * @unit s
+ * @min 0.2
+ * @max 1.0
+ * @decimal 2
+ * @increment 0.05
+ * @group FW Attitude Control
+ */
+PARAM_DEFINE_FLOAT(FW_Y_TC, 0.4f);
+
 /**
  * Roll control to yaw control feedforward gain.
  *