void VtolAttitudeControl::task_main()
{
	PX4_WARN("started");
	fflush(stdout);

	/* do subscriptions */
	_v_att_sp_sub          = orb_subscribe(ORB_ID(vehicle_attitude_setpoint));
	_mc_virtual_att_sp_sub = orb_subscribe(ORB_ID(mc_virtual_attitude_setpoint));
	_fw_virtual_att_sp_sub = orb_subscribe(ORB_ID(fw_virtual_attitude_setpoint));
	_mc_virtual_v_rates_sp_sub = orb_subscribe(ORB_ID(mc_virtual_rates_setpoint));
	_fw_virtual_v_rates_sp_sub = orb_subscribe(ORB_ID(fw_virtual_rates_setpoint));
	_v_att_sub             = orb_subscribe(ORB_ID(vehicle_attitude));
	_v_att_sp_sub          = orb_subscribe(ORB_ID(vehicle_attitude_setpoint));
	_v_control_mode_sub    = orb_subscribe(ORB_ID(vehicle_control_mode));
	_params_sub            = orb_subscribe(ORB_ID(parameter_update));
	_manual_control_sp_sub = orb_subscribe(ORB_ID(manual_control_setpoint));
	_armed_sub             = orb_subscribe(ORB_ID(actuator_armed));
	_local_pos_sub         = orb_subscribe(ORB_ID(vehicle_local_position));
	_airspeed_sub          = orb_subscribe(ORB_ID(airspeed));
	_battery_status_sub	   = orb_subscribe(ORB_ID(battery_status));
	_vehicle_cmd_sub	   = orb_subscribe(ORB_ID(vehicle_command));

	_actuator_inputs_mc    = orb_subscribe(ORB_ID(actuator_controls_virtual_mc));
	_actuator_inputs_fw    = orb_subscribe(ORB_ID(actuator_controls_virtual_fw));

	parameters_update();  // initialize parameter cache

	/* update vtol vehicle status*/
	_vtol_vehicle_status.fw_permanent_stab = _params.vtol_fw_permanent_stab == 1 ? true : false;

	// make sure we start with idle in mc mode
	_vtol_type->set_idle_mc();

	/* wakeup source*/
	px4_pollfd_struct_t fds[3] = {};	/*input_mc, input_fw, parameters*/

	fds[0].fd     = _actuator_inputs_mc;
	fds[0].events = POLLIN;
	fds[1].fd     = _actuator_inputs_fw;
	fds[1].events = POLLIN;
	fds[2].fd     = _params_sub;
	fds[2].events = POLLIN;

	while (!_task_should_exit) {
		/*Advertise/Publish vtol vehicle status*/
		if (_vtol_vehicle_status_pub != nullptr) {
			orb_publish(ORB_ID(vtol_vehicle_status), _vtol_vehicle_status_pub, &_vtol_vehicle_status);

		} else {
			_vtol_vehicle_status.timestamp = hrt_absolute_time();
			_vtol_vehicle_status_pub = orb_advertise(ORB_ID(vtol_vehicle_status), &_vtol_vehicle_status);
		}

		/* wait for up to 100ms for data */
		int pret = px4_poll(&fds[0], (sizeof(fds) / sizeof(fds[0])), 100);


		/* timed out - periodic check for _task_should_exit */
		if (pret == 0) {
			continue;
		}

		/* this is undesirable but not much we can do - might want to flag unhappy status */
		if (pret < 0) {
			warn("poll error %d, %d", pret, errno);
			/* sleep a bit before next try */
			usleep(100000);
			continue;
		}

		if (fds[2].revents & POLLIN) {	//parameters were updated, read them now
			/* read from param to clear updated flag */
			struct parameter_update_s update;
			orb_copy(ORB_ID(parameter_update), _params_sub, &update);

			/* update parameters from storage */
			parameters_update();
		}

		_vtol_vehicle_status.fw_permanent_stab = _params.vtol_fw_permanent_stab == 1 ? true : false;

		mc_virtual_att_sp_poll();
		fw_virtual_att_sp_poll();
		vehicle_control_mode_poll();	//Check for changes in vehicle control mode.
		vehicle_manual_poll();			//Check for changes in manual inputs.
		arming_status_poll();			//Check for arming status updates.
		vehicle_attitude_setpoint_poll();//Check for changes in attitude set points
		vehicle_attitude_poll();		//Check for changes in attitude
		actuator_controls_mc_poll();	//Check for changes in mc_attitude_control output
		actuator_controls_fw_poll();	//Check for changes in fw_attitude_control output
		vehicle_rates_sp_mc_poll();
		vehicle_rates_sp_fw_poll();
		parameters_update_poll();
		vehicle_local_pos_poll();			// Check for new sensor values
		vehicle_airspeed_poll();
		vehicle_battery_poll();
		vehicle_cmd_poll();

		// update the vtol state machine which decides which mode we are in
		_vtol_type->update_vtol_state();

		// reset transition command if not in offboard control
		if (!_v_control_mode.flag_control_offboard_enabled) {
			if (_vtol_type->get_mode() == ROTARY_WING) {
				_transition_command = vehicle_status_s::VEHICLE_VTOL_STATE_MC;

			} else if (_vtol_type->get_mode() == FIXED_WING) {
				_transition_command = vehicle_status_s::VEHICLE_VTOL_STATE_FW;
			}
		}

		// check in which mode we are in and call mode specific functions
		if (_vtol_type->get_mode() == ROTARY_WING) {
			// vehicle is in rotary wing mode
			_vtol_vehicle_status.vtol_in_rw_mode = true;
			_vtol_vehicle_status.vtol_in_trans_mode = false;

			// got data from mc attitude controller
			if (fds[0].revents & POLLIN) {
				orb_copy(ORB_ID(actuator_controls_virtual_mc), _actuator_inputs_mc, &_actuators_mc_in);

				_vtol_type->update_mc_state();

				fill_mc_att_rates_sp();
			}

		} else if (_vtol_type->get_mode() == FIXED_WING) {
			// vehicle is in fw mode
			_vtol_vehicle_status.vtol_in_rw_mode = false;
			_vtol_vehicle_status.vtol_in_trans_mode = false;

			// got data from fw attitude controller
			if (fds[1].revents & POLLIN) {
				orb_copy(ORB_ID(actuator_controls_virtual_fw), _actuator_inputs_fw, &_actuators_fw_in);
				vehicle_manual_poll();

				_vtol_type->update_fw_state();

				fill_fw_att_rates_sp();
			}

		} else if (_vtol_type->get_mode() == TRANSITION) {
			// vehicle is doing a transition
			_vtol_vehicle_status.vtol_in_trans_mode = true;
			_vtol_vehicle_status.vtol_in_rw_mode = true; //making mc attitude controller work during transition

			bool got_new_data = false;

			if (fds[0].revents & POLLIN) {
				orb_copy(ORB_ID(actuator_controls_virtual_mc), _actuator_inputs_mc, &_actuators_mc_in);
				got_new_data = true;
			}

			if (fds[1].revents & POLLIN) {
				orb_copy(ORB_ID(actuator_controls_virtual_fw), _actuator_inputs_fw, &_actuators_fw_in);
				got_new_data = true;
			}

			// update transition state if got any new data
			if (got_new_data) {
				_vtol_type->update_transition_state();
				fill_mc_att_rates_sp();
				publish_att_sp();
			}

		} else if (_vtol_type->get_mode() == EXTERNAL) {
			// we are using external module to generate attitude/thrust setpoint
			_vtol_type->update_external_state();
		}

		publish_att_sp();
		_vtol_type->fill_actuator_outputs();

		/* Only publish if the proper mode(s) are enabled */
		if (_v_control_mode.flag_control_attitude_enabled ||
		    _v_control_mode.flag_control_rates_enabled ||
		    _v_control_mode.flag_control_manual_enabled) {
			if (_actuators_0_pub != nullptr) {
				orb_publish(ORB_ID(actuator_controls_0), _actuators_0_pub, &_actuators_out_0);

			} else {
				_actuators_0_pub = orb_advertise(ORB_ID(actuator_controls_0), &_actuators_out_0);
			}

			if (_actuators_1_pub != nullptr) {
				orb_publish(ORB_ID(actuator_controls_1), _actuators_1_pub, &_actuators_out_1);

			} else {
				_actuators_1_pub = orb_advertise(ORB_ID(actuator_controls_1), &_actuators_out_1);
			}
		}

		// publish the attitude rates setpoint
		if (_v_rates_sp_pub != nullptr) {
			orb_publish(ORB_ID(vehicle_rates_setpoint), _v_rates_sp_pub, &_v_rates_sp);

		} else {
			_v_rates_sp_pub = orb_advertise(ORB_ID(vehicle_rates_setpoint), &_v_rates_sp);
		}
	}

	warnx("exit");
	_control_task = -1;
	return;
}
void
FixedwingPositionControl::task_main()
{

	/* inform about start */
	warnx("Initializing..");
	fflush(stdout);

	/*
	 * do subscriptions
	 */
	_global_pos_sub = orb_subscribe(ORB_ID(vehicle_global_position));
	_pos_sp_triplet_sub = orb_subscribe(ORB_ID(position_setpoint_triplet));
	_att_sub = orb_subscribe(ORB_ID(vehicle_attitude));
	_sensor_combined_sub = orb_subscribe(ORB_ID(sensor_combined));
	_control_mode_sub = orb_subscribe(ORB_ID(vehicle_control_mode));
	_airspeed_sub = orb_subscribe(ORB_ID(airspeed));
	_params_sub = orb_subscribe(ORB_ID(parameter_update));
	_manual_control_sub = orb_subscribe(ORB_ID(manual_control_setpoint));
	_range_finder_sub = orb_subscribe(ORB_ID(sensor_range_finder));

	/* rate limit vehicle status updates to 5Hz */
	orb_set_interval(_control_mode_sub, 200);
	/* rate limit position updates to 50 Hz */
	orb_set_interval(_global_pos_sub, 20);

	/* abort on a nonzero return value from the parameter init */
	if (parameters_update()) {
		/* parameter setup went wrong, abort */
		warnx("aborting startup due to errors.");
		_task_should_exit = true;
	}

	/* wakeup source(s) */
	struct pollfd fds[2];

	/* Setup of loop */
	fds[0].fd = _params_sub;
	fds[0].events = POLLIN;
	fds[1].fd = _global_pos_sub;
	fds[1].events = POLLIN;

	while (!_task_should_exit) {

		/* wait for up to 500ms for data */
		int pret = poll(&fds[0], (sizeof(fds) / sizeof(fds[0])), 100);

		/* timed out - periodic check for _task_should_exit, etc. */
		if (pret == 0)
			continue;

		/* this is undesirable but not much we can do - might want to flag unhappy status */
		if (pret < 0) {
			warn("poll error %d, %d", pret, errno);
			continue;
		}

		perf_begin(_loop_perf);

		/* check vehicle status for changes to publication state */
		vehicle_control_mode_poll();

		/* only update parameters if they changed */
		if (fds[0].revents & POLLIN) {
			/* read from param to clear updated flag */
			struct parameter_update_s update;
			orb_copy(ORB_ID(parameter_update), _params_sub, &update);

			/* update parameters from storage */
			parameters_update();
		}

		/* only run controller if position changed */
		if (fds[1].revents & POLLIN) {

			/* XXX Hack to get mavlink output going */
			if (_mavlink_fd < 0) {
				/* try to open the mavlink log device every once in a while */
				_mavlink_fd = open(MAVLINK_LOG_DEVICE, 0);
			}

			static uint64_t last_run = 0;
			float deltaT = (hrt_absolute_time() - last_run) / 1000000.0f;
			last_run = hrt_absolute_time();

			/* guard against too large deltaT's */
			if (deltaT > 1.0f)
				deltaT = 0.01f;

			/* load local copies */
			orb_copy(ORB_ID(vehicle_global_position), _global_pos_sub, &_global_pos);

			// XXX add timestamp check
			_global_pos_valid = true;

			vehicle_attitude_poll();
			vehicle_setpoint_poll();
			vehicle_sensor_combined_poll();
			vehicle_airspeed_poll();
			range_finder_poll();
			// vehicle_baro_poll();

			math::Vector<2> ground_speed(_global_pos.vel_n, _global_pos.vel_e);
			math::Vector<2> current_position((float)_global_pos.lat, (float)_global_pos.lon);

			/*
			 * Attempt to control position, on success (= sensors present and not in manual mode),
			 * publish setpoint.
			 */
			if (control_position(current_position, ground_speed, _pos_sp_triplet)) {
				_att_sp.timestamp = hrt_absolute_time();

				/* lazily publish the setpoint only once available */
				if (_attitude_sp_pub > 0) {
					/* publish the attitude setpoint */
					orb_publish(ORB_ID(vehicle_attitude_setpoint), _attitude_sp_pub, &_att_sp);

				} else {
					/* advertise and publish */
					_attitude_sp_pub = orb_advertise(ORB_ID(vehicle_attitude_setpoint), &_att_sp);
				}

				/* XXX check if radius makes sense here */
				float turn_distance = _l1_control.switch_distance(100.0f);

				/* lazily publish navigation capabilities */
				if (fabsf(turn_distance - _nav_capabilities.turn_distance) > FLT_EPSILON && turn_distance > 0) {

					/* set new turn distance */
					_nav_capabilities.turn_distance = turn_distance;

					navigation_capabilities_publish();

				}

			}

		}

		perf_end(_loop_perf);
	}

	warnx("exiting.\n");

	_control_task = -1;
	_exit(0);
}