FlightTaskManual: fix for the sideways oscillations in fast foward flight when using the vehicle yaw estimate

src/lib/FlightTasks/tasks/FlightTaskManual.cpp

@@ -145,6 +145,17 @@ bool FlightTaskManual::update()
 	return true;
 }
 
+float FlightTaskManual::_get_input_frame_yaw()
+{
+	/* using constant yaw angle from setpoint here to prevent sideways oscillation in fast forward flight */
+	if (PX4_ISFINITE(_hold_yaw)) {
+		return _hold_yaw;
+
+	} else {
+		return _yaw;
+	}
+}
+
 void FlightTaskManual::_updateYaw()
 {
 	const float yaw_speed = _sticks(3) * math::radians(_man_yaw_max.get());

src/lib/FlightTasks/tasks/FlightTaskManual.hpp

@@ -67,7 +67,7 @@ protected:
 	bool _evaluateSticks();
 	bool _sticks_data_required = true; /**< let sibling task define if it depends on stick data */
 
-	float _get_input_frame_yaw() { return _yaw; }
+	float _get_input_frame_yaw();
 	virtual void _scaleVelocity(matrix::Vector3f &velocity);
 
 	control::BlockParamFloat _z_vel_max_up; /**< maximal vertical velocity when flying upwards with the stick */