void
MulticopterPositionControl::task_main()
{
	warnx("started");

	_mavlink_fd = open(MAVLINK_LOG_DEVICE, 0);
	mavlink_log_info(_mavlink_fd, "[mpc] started");

	/*
	 * do subscriptions
	 */
	_att_sub = orb_subscribe(ORB_ID(vehicle_attitude));
	_att_sp_sub = orb_subscribe(ORB_ID(vehicle_attitude_setpoint));
	_control_mode_sub = orb_subscribe(ORB_ID(vehicle_control_mode));
	_params_sub = orb_subscribe(ORB_ID(parameter_update));
	_manual_sub = orb_subscribe(ORB_ID(manual_control_setpoint));
	_arming_sub = orb_subscribe(ORB_ID(actuator_armed));
	_local_pos_sub = orb_subscribe(ORB_ID(vehicle_local_position));
	_pos_sp_triplet_sub = orb_subscribe(ORB_ID(position_setpoint_triplet));

	parameters_update(true);

	/* initialize values of critical structs until first regular update */
	_arming.armed = false;

	/* get an initial update for all sensor and status data */
	poll_subscriptions();

	bool reset_int_z = true;
	bool reset_int_z_manual = false;
	bool reset_int_xy = true;
	bool was_armed = false;

	hrt_abstime t_prev = 0;

	const float alt_ctl_dz = 0.2f;
	const float pos_ctl_dz = 0.05f;

	math::Vector<3> sp_move_rate;
	sp_move_rate.zero();
	math::Vector<3> thrust_int;
	thrust_int.zero();
	math::Matrix<3, 3> R;
	R.identity();

	/* wakeup source */
	struct pollfd fds[1];

	fds[0].fd = _local_pos_sub;
	fds[0].events = POLLIN;

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

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

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

		poll_subscriptions();
		parameters_update(false);

		hrt_abstime t = hrt_absolute_time();
		float dt = t_prev != 0 ? (t - t_prev) * 0.000001f : 0.0f;
		t_prev = t;

		if (_control_mode.flag_armed && !was_armed) {
			/* reset setpoints and integrals on arming */
			_reset_pos_sp = true;
			_reset_alt_sp = true;
			reset_int_z = true;
			reset_int_xy = true;
		}

		was_armed = _control_mode.flag_armed;

		update_ref();

		if (_control_mode.flag_control_altitude_enabled ||
		    _control_mode.flag_control_position_enabled ||
		    _control_mode.flag_control_climb_rate_enabled ||
		    _control_mode.flag_control_velocity_enabled) {

			_pos(0) = _local_pos.x;
			_pos(1) = _local_pos.y;
			_pos(2) = _local_pos.z;

			_vel(0) = _local_pos.vx;
			_vel(1) = _local_pos.vy;
			_vel(2) = _local_pos.vz;

			sp_move_rate.zero();

			/* select control source */
			if (_control_mode.flag_control_manual_enabled) {
				/* manual control */
				if (_control_mode.flag_control_altitude_enabled) {
					/* reset alt setpoint to current altitude if needed */
					reset_alt_sp();

					/* move altitude setpoint with throttle stick */
					sp_move_rate(2) = -scale_control(_manual.z - 0.5f, 0.5f, alt_ctl_dz);
				}

				if (_control_mode.flag_control_position_enabled) {
					/* reset position setpoint to current position if needed */
					reset_pos_sp();

					/* move position setpoint with roll/pitch stick */
					sp_move_rate(0) = _manual.x;
					sp_move_rate(1) = _manual.y;
				}

				/* limit setpoint move rate */
				float sp_move_norm = sp_move_rate.length();

				if (sp_move_norm > 1.0f) {
					sp_move_rate /= sp_move_norm;
				}

				/* scale to max speed and rotate around yaw */
				math::Matrix<3, 3> R_yaw_sp;
				R_yaw_sp.from_euler(0.0f, 0.0f, _att_sp.yaw_body);
				sp_move_rate = R_yaw_sp * sp_move_rate.emult(_params.vel_max);

				/* move position setpoint */
				_pos_sp += sp_move_rate * dt;

				/* check if position setpoint is too far from actual position */
				math::Vector<3> pos_sp_offs;
				pos_sp_offs.zero();

				if (_control_mode.flag_control_position_enabled) {
					pos_sp_offs(0) = (_pos_sp(0) - _pos(0)) / _params.sp_offs_max(0);
					pos_sp_offs(1) = (_pos_sp(1) - _pos(1)) / _params.sp_offs_max(1);
				}

				if (_control_mode.flag_control_altitude_enabled) {
					pos_sp_offs(2) = (_pos_sp(2) - _pos(2)) / _params.sp_offs_max(2);
				}

				float pos_sp_offs_norm = pos_sp_offs.length();

				if (pos_sp_offs_norm > 1.0f) {
					pos_sp_offs /= pos_sp_offs_norm;
					_pos_sp = _pos + pos_sp_offs.emult(_params.sp_offs_max);
				}

			} else {
				/* AUTO */
				bool updated;
				orb_check(_pos_sp_triplet_sub, &updated);

				if (updated) {
					orb_copy(ORB_ID(position_setpoint_triplet), _pos_sp_triplet_sub, &_pos_sp_triplet);
				}

				if (_pos_sp_triplet.current.valid) {
					/* in case of interrupted mission don't go to waypoint but stay at current position */
					_reset_pos_sp = true;
					_reset_alt_sp = true;

					/* project setpoint to local frame */
					map_projection_project(&_ref_pos,
							       _pos_sp_triplet.current.lat, _pos_sp_triplet.current.lon,
							       &_pos_sp.data[0], &_pos_sp.data[1]);
					_pos_sp(2) = -(_pos_sp_triplet.current.alt - _ref_alt);

					/* update yaw setpoint if needed */
					if (isfinite(_pos_sp_triplet.current.yaw)) {
						_att_sp.yaw_body = _pos_sp_triplet.current.yaw;
					}

				} else {
					/* no waypoint, loiter, reset position setpoint if needed */
					reset_pos_sp();
					reset_alt_sp();
				}
			}

			/* fill local position setpoint */
			_local_pos_sp.x = _pos_sp(0);
			_local_pos_sp.y = _pos_sp(1);
			_local_pos_sp.z = _pos_sp(2);
			_local_pos_sp.yaw = _att_sp.yaw_body;

			/* publish local position setpoint */
			if (_local_pos_sp_pub > 0) {
				orb_publish(ORB_ID(vehicle_local_position_setpoint), _local_pos_sp_pub, &_local_pos_sp);

			} else {
				_local_pos_sp_pub = orb_advertise(ORB_ID(vehicle_local_position_setpoint), &_local_pos_sp);
			}

			if (!_control_mode.flag_control_manual_enabled && _pos_sp_triplet.current.valid && _pos_sp_triplet.current.type == SETPOINT_TYPE_IDLE) {
				/* idle state, don't run controller and set zero thrust */
				R.identity();
				memcpy(&_att_sp.R_body[0][0], R.data, sizeof(_att_sp.R_body));
				_att_sp.R_valid = true;

				_att_sp.roll_body = 0.0f;
				_att_sp.pitch_body = 0.0f;
				_att_sp.yaw_body = _att.yaw;
				_att_sp.thrust = 0.0f;

				_att_sp.timestamp = hrt_absolute_time();

				/* publish attitude setpoint */
				if (_att_sp_pub > 0) {
					orb_publish(ORB_ID(vehicle_attitude_setpoint), _att_sp_pub, &_att_sp);

				} else {
					_att_sp_pub = orb_advertise(ORB_ID(vehicle_attitude_setpoint), &_att_sp);
				}

			} else {
				/* run position & altitude controllers, calculate velocity setpoint */
				math::Vector<3> pos_err = _pos_sp - _pos;

				_vel_sp = pos_err.emult(_params.pos_p) + sp_move_rate.emult(_params.vel_ff);

				if (!_control_mode.flag_control_altitude_enabled) {
					_reset_alt_sp = true;
					_vel_sp(2) = 0.0f;
				}

				if (!_control_mode.flag_control_position_enabled) {
					_reset_pos_sp = true;
					_vel_sp(0) = 0.0f;
					_vel_sp(1) = 0.0f;
				}

				/* use constant descend rate when landing, ignore altitude setpoint */
				if (!_control_mode.flag_control_manual_enabled && _pos_sp_triplet.current.valid && _pos_sp_triplet.current.type == SETPOINT_TYPE_LAND) {
					_vel_sp(2) = _params.land_speed;
				}

				if (!_control_mode.flag_control_manual_enabled) {
					/* limit 3D speed only in non-manual modes */
					float vel_sp_norm = _vel_sp.edivide(_params.vel_max).length();

					if (vel_sp_norm > 1.0f) {
						_vel_sp /= vel_sp_norm;
					}
				}

				_global_vel_sp.vx = _vel_sp(0);
				_global_vel_sp.vy = _vel_sp(1);
				_global_vel_sp.vz = _vel_sp(2);

				/* publish velocity setpoint */
				if (_global_vel_sp_pub > 0) {
					orb_publish(ORB_ID(vehicle_global_velocity_setpoint), _global_vel_sp_pub, &_global_vel_sp);

				} else {
					_global_vel_sp_pub = orb_advertise(ORB_ID(vehicle_global_velocity_setpoint), &_global_vel_sp);
				}

				if (_control_mode.flag_control_climb_rate_enabled || _control_mode.flag_control_velocity_enabled) {
					/* reset integrals if needed */
					if (_control_mode.flag_control_climb_rate_enabled) {
						if (reset_int_z) {
							reset_int_z = false;
							float i = _params.thr_min;

							if (reset_int_z_manual) {
								i = _manual.z;

								if (i < _params.thr_min) {
									i = _params.thr_min;

								} else if (i > _params.thr_max) {
									i = _params.thr_max;
								}
							}

							thrust_int(2) = -i;
						}

					} else {
						reset_int_z = true;
					}

					if (_control_mode.flag_control_velocity_enabled) {
						if (reset_int_xy) {
							reset_int_xy = false;
							thrust_int(0) = 0.0f;
							thrust_int(1) = 0.0f;
						}

					} else {
						reset_int_xy = true;
					}

					/* velocity error */
					math::Vector<3> vel_err = _vel_sp - _vel;

					/* derivative of velocity error, not includes setpoint acceleration */
					math::Vector<3> vel_err_d = (sp_move_rate - _vel).emult(_params.pos_p) - (_vel - _vel_prev) / dt;
					_vel_prev = _vel;

					/* thrust vector in NED frame */
					math::Vector<3> thrust_sp = vel_err.emult(_params.vel_p) + vel_err_d.emult(_params.vel_d) + thrust_int;

					if (!_control_mode.flag_control_velocity_enabled) {
						thrust_sp(0) = 0.0f;
						thrust_sp(1) = 0.0f;
					}

					if (!_control_mode.flag_control_climb_rate_enabled) {
						thrust_sp(2) = 0.0f;
					}

					/* limit thrust vector and check for saturation */
					bool saturation_xy = false;
					bool saturation_z = false;

					/* limit min lift */
					float thr_min = _params.thr_min;

					if (!_control_mode.flag_control_velocity_enabled && thr_min < 0.0f) {
						/* don't allow downside thrust direction in manual attitude mode */
						thr_min = 0.0f;
					}

					float tilt_max = _params.tilt_max_air;

					/* adjust limits for landing mode */
					if (!_control_mode.flag_control_manual_enabled && _pos_sp_triplet.current.valid &&
					    _pos_sp_triplet.current.type == SETPOINT_TYPE_LAND) {
						/* limit max tilt and min lift when landing */
						tilt_max = _params.tilt_max_land;

						if (thr_min < 0.0f) {
							thr_min = 0.0f;
						}
					}

					/* limit min lift */
					if (-thrust_sp(2) < thr_min) {
						thrust_sp(2) = -thr_min;
						saturation_z = true;
					}

					if (_control_mode.flag_control_velocity_enabled) {
						/* limit max tilt */
						if (thr_min >= 0.0f && tilt_max < M_PI / 2 - 0.05f) {
							/* absolute horizontal thrust */
							float thrust_sp_xy_len = math::Vector<2>(thrust_sp(0), thrust_sp(1)).length();

							if (thrust_sp_xy_len > 0.01f) {
								/* max horizontal thrust for given vertical thrust*/
								float thrust_xy_max = -thrust_sp(2) * tanf(tilt_max);

								if (thrust_sp_xy_len > thrust_xy_max) {
									float k = thrust_xy_max / thrust_sp_xy_len;
									thrust_sp(0) *= k;
									thrust_sp(1) *= k;
									saturation_xy = true;
								}
							}
						}

					} else {
						/* thrust compensation for altitude only control mode */
						float att_comp;

						if (_att.R[2][2] > TILT_COS_MAX) {
							att_comp = 1.0f / _att.R[2][2];

						} else if (_att.R[2][2] > 0.0f) {
							att_comp = ((1.0f / TILT_COS_MAX - 1.0f) / TILT_COS_MAX) * _att.R[2][2] + 1.0f;
							saturation_z = true;

						} else {
							att_comp = 1.0f;
							saturation_z = true;
						}

						thrust_sp(2) *= att_comp;
					}

					/* limit max thrust */
					float thrust_abs = thrust_sp.length();

					if (thrust_abs > _params.thr_max) {
						if (thrust_sp(2) < 0.0f) {
							if (-thrust_sp(2) > _params.thr_max) {
								/* thrust Z component is too large, limit it */
								thrust_sp(0) = 0.0f;
								thrust_sp(1) = 0.0f;
								thrust_sp(2) = -_params.thr_max;
								saturation_xy = true;
								saturation_z = true;

							} else {
								/* preserve thrust Z component and lower XY, keeping altitude is more important than position */
								float thrust_xy_max = sqrtf(_params.thr_max * _params.thr_max - thrust_sp(2) * thrust_sp(2));
								float thrust_xy_abs = math::Vector<2>(thrust_sp(0), thrust_sp(1)).length();
								float k = thrust_xy_max / thrust_xy_abs;
								thrust_sp(0) *= k;
								thrust_sp(1) *= k;
								saturation_xy = true;
							}

						} else {
							/* Z component is negative, going down, simply limit thrust vector */
							float k = _params.thr_max / thrust_abs;
							thrust_sp *= k;
							saturation_xy = true;
							saturation_z = true;
						}

						thrust_abs = _params.thr_max;
					}

					/* update integrals */
					if (_control_mode.flag_control_velocity_enabled && !saturation_xy) {
						thrust_int(0) += vel_err(0) * _params.vel_i(0) * dt;
						thrust_int(1) += vel_err(1) * _params.vel_i(1) * dt;
					}

					if (_control_mode.flag_control_climb_rate_enabled && !saturation_z) {
						thrust_int(2) += vel_err(2) * _params.vel_i(2) * dt;

						/* protection against flipping on ground when landing */
						if (thrust_int(2) > 0.0f) {
							thrust_int(2) = 0.0f;
						}
					}

					/* calculate attitude setpoint from thrust vector */
					if (_control_mode.flag_control_velocity_enabled) {
						/* desired body_z axis = -normalize(thrust_vector) */
						math::Vector<3> body_x;
						math::Vector<3> body_y;
						math::Vector<3> body_z;

						if (thrust_abs > SIGMA) {
							body_z = -thrust_sp / thrust_abs;

						} else {
							/* no thrust, set Z axis to safe value */
							body_z.zero();
							body_z(2) = 1.0f;
						}

						/* vector of desired yaw direction in XY plane, rotated by PI/2 */
						math::Vector<3> y_C(-sinf(_att_sp.yaw_body), cosf(_att_sp.yaw_body), 0.0f);

						if (fabsf(body_z(2)) > SIGMA) {
							/* desired body_x axis, orthogonal to body_z */
							body_x = y_C % body_z;

							/* keep nose to front while inverted upside down */
							if (body_z(2) < 0.0f) {
								body_x = -body_x;
							}

							body_x.normalize();

						} else {
							/* desired thrust is in XY plane, set X downside to construct correct matrix,
							 * but yaw component will not be used actually */
							body_x.zero();
							body_x(2) = 1.0f;
						}

						/* desired body_y axis */
						body_y = body_z % body_x;

						/* fill rotation matrix */
						for (int i = 0; i < 3; i++) {
							R(i, 0) = body_x(i);
							R(i, 1) = body_y(i);
							R(i, 2) = body_z(i);
						}

						/* copy rotation matrix to attitude setpoint topic */
						memcpy(&_att_sp.R_body[0][0], R.data, sizeof(_att_sp.R_body));
						_att_sp.R_valid = true;

						/* calculate euler angles, for logging only, must not be used for control */
						math::Vector<3> euler = R.to_euler();
						_att_sp.roll_body = euler(0);
						_att_sp.pitch_body = euler(1);
						/* yaw already used to construct rot matrix, but actual rotation matrix can have different yaw near singularity */

					} else if (!_control_mode.flag_control_manual_enabled) {
						/* autonomous altitude control without position control (failsafe landing),
						 * force level attitude, don't change yaw */
						R.from_euler(0.0f, 0.0f, _att_sp.yaw_body);

						/* copy rotation matrix to attitude setpoint topic */
						memcpy(&_att_sp.R_body[0][0], R.data, sizeof(_att_sp.R_body));
						_att_sp.R_valid = true;

						_att_sp.roll_body = 0.0f;
						_att_sp.pitch_body = 0.0f;
					}

					_att_sp.thrust = thrust_abs;

					_att_sp.timestamp = hrt_absolute_time();

					/* publish attitude setpoint */
					if (_att_sp_pub > 0) {
						orb_publish(ORB_ID(vehicle_attitude_setpoint), _att_sp_pub, &_att_sp);

					} else {
						_att_sp_pub = orb_advertise(ORB_ID(vehicle_attitude_setpoint), &_att_sp);
					}

				} else {
					reset_int_z = true;
				}
			}

		} else {
			/* position controller disabled, reset setpoints */
			_reset_alt_sp = true;
			_reset_pos_sp = true;
			reset_int_z = true;
			reset_int_xy = true;
		}

		/* reset altitude controller integral (hovering throttle) to manual throttle after manual throttle control */
		reset_int_z_manual = _control_mode.flag_armed && _control_mode.flag_control_manual_enabled && !_control_mode.flag_control_climb_rate_enabled;
	}

	warnx("stopped");
	mavlink_log_info(_mavlink_fd, "[mpc] stopped");

	_control_task = -1;
	_exit(0);
}
void
MulticopterPositionControl::task_main()
{

	_mavlink_fd = open(MAVLINK_LOG_DEVICE, 0);

	/*
	 * do subscriptions
	 */
	_att_sub = orb_subscribe(ORB_ID(vehicle_attitude));
	_att_sp_sub = orb_subscribe(ORB_ID(vehicle_attitude_setpoint));
	_control_mode_sub = orb_subscribe(ORB_ID(vehicle_control_mode));
	_params_sub = orb_subscribe(ORB_ID(parameter_update));
	_manual_sub = orb_subscribe(ORB_ID(manual_control_setpoint));
	_arming_sub = orb_subscribe(ORB_ID(actuator_armed));
	_local_pos_sub = orb_subscribe(ORB_ID(vehicle_local_position));
	_pos_sp_triplet_sub = orb_subscribe(ORB_ID(position_setpoint_triplet));
	_local_pos_sp_sub = orb_subscribe(ORB_ID(vehicle_local_position_setpoint));
	_global_vel_sp_sub = orb_subscribe(ORB_ID(vehicle_global_velocity_setpoint));


	parameters_update(true);

	/* initialize values of critical structs until first regular update */
	_arming.armed = false;

	/* get an initial update for all sensor and status data */
	poll_subscriptions();

	bool reset_int_z = true;
	bool reset_int_z_manual = false;
	bool reset_int_xy = true;
	bool reset_yaw_sp = true;
	bool was_armed = false;

	hrt_abstime t_prev = 0;
	_hover_time = 0.0; // miao:
	_mode_mission = 1;
	math::Vector<3> thrust_int;
	thrust_int.zero();
	math::Matrix<3, 3> R;
	R.identity();

	/* wakeup source */
	struct pollfd fds[1];

	fds[0].fd = _local_pos_sub;
	fds[0].events = POLLIN;

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

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

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

		poll_subscriptions();
		parameters_update(false);

		hrt_abstime t = hrt_absolute_time();
		float dt = t_prev != 0 ? (t - t_prev) * 0.000001f : 0.0f;
		t_prev = t;

		if (_control_mode.flag_armed && !was_armed) {
			/* reset setpoints and integrals on arming */
			_reset_pos_sp = true;
			_reset_alt_sp = true;
			reset_int_z = true;
			reset_int_xy = true;
			reset_yaw_sp = true;
			_reset_mission = true;//miao:
		}

		//Update previous arming state
		was_armed = _control_mode.flag_armed;

		update_ref();

		if (_control_mode.flag_control_altitude_enabled ||
		    _control_mode.flag_control_position_enabled ||
		    _control_mode.flag_control_climb_rate_enabled ||
		    _control_mode.flag_control_velocity_enabled) {

			_pos(0) = _local_pos.x;
			_pos(1) = _local_pos.y;
			_pos(2) = _local_pos.z;

			_vel(0) = _local_pos.vx;
			_vel(1) = _local_pos.vy;
			_vel(2) = _local_pos.vz;

			_vel_ff.zero();
			_sp_move_rate.zero();

			/* select control source */
			if (_control_mode.flag_control_manual_enabled) {
				/* manual control */
				control_manual(dt);
				_mode_auto = false;

			} else if (_control_mode.flag_control_offboard_enabled) {
				/* offboard control */
				control_offboard(dt);
				_mode_auto = false;

			} else {
				/* AUTO */
				control_auto(dt);
			}

			if (!_control_mode.flag_control_manual_enabled && _pos_sp_triplet.current.valid && _pos_sp_triplet.current.type == position_setpoint_s::SETPOINT_TYPE_IDLE) {
				/* idle state, don't run controller and set zero thrust */
				R.identity();
				memcpy(&_att_sp.R_body[0], R.data, sizeof(_att_sp.R_body));
				_att_sp.R_valid = true;

				_att_sp.roll_body = 0.0f;
				_att_sp.pitch_body = 0.0f;
				_att_sp.yaw_body = _att.yaw;
				_att_sp.thrust = 0.0f;

				_att_sp.timestamp = hrt_absolute_time();

				/* publish attitude setpoint */
				if (_att_sp_pub > 0) {
					orb_publish(ORB_ID(vehicle_attitude_setpoint), _att_sp_pub, &_att_sp);

				} else {
					_att_sp_pub = orb_advertise(ORB_ID(vehicle_attitude_setpoint), &_att_sp);
				}

			} else {
				/* run position & altitude controllers, calculate velocity setpoint */
				math::Vector<3> pos_err = _pos_sp - _pos;

				_vel_sp = pos_err.emult(_params.pos_p) + _vel_ff;

				if (!_control_mode.flag_control_altitude_enabled) {
					_reset_alt_sp = true;
					_vel_sp(2) = 0.0f;
				}

				if (!_control_mode.flag_control_position_enabled) {
					_reset_pos_sp = true;
					_vel_sp(0) = 0.0f;
					_vel_sp(1) = 0.0f;
				}

				/* use constant descend rate when landing, ignore altitude setpoint */
				//if (!_control_mode.flag_control_manual_enabled && _pos_sp_triplet.current.valid && _pos_sp_triplet.current.type == position_setpoint_s::SETPOINT_TYPE_LAND) {
				// miao: for auto landing test with manual mode
				if (_mode_mission==3) {
					_vel_sp(2) = _params.land_speed;
				}

				_global_vel_sp.vx = _vel_sp(0);
				_global_vel_sp.vy = _vel_sp(1);
				_global_vel_sp.vz = _vel_sp(2);

				/* publish velocity setpoint */
				if (_global_vel_sp_pub > 0) {
					orb_publish(ORB_ID(vehicle_global_velocity_setpoint), _global_vel_sp_pub, &_global_vel_sp);

				} else {
					_global_vel_sp_pub = orb_advertise(ORB_ID(vehicle_global_velocity_setpoint), &_global_vel_sp);
				}

				if (_control_mode.flag_control_climb_rate_enabled || _control_mode.flag_control_velocity_enabled) {
					/* reset integrals if needed */
					if (_control_mode.flag_control_climb_rate_enabled) {
						if (reset_int_z) {
							reset_int_z = false;
							float i = _params.thr_min;

							if (reset_int_z_manual) {
								i = _manual.z;

								if (i < _params.thr_min) {
									i = _params.thr_min;

								} else if (i > _params.thr_max) {
									i = _params.thr_max;
								}
							}

							thrust_int(2) = -i;
						}

					} else {
						reset_int_z = true;
					}

					if (_control_mode.flag_control_velocity_enabled) {
						if (reset_int_xy) {
							reset_int_xy = false;
							thrust_int(0) = 0.0f;
							thrust_int(1) = 0.0f;
						}

					} else {
						reset_int_xy = true;
					}

					/* velocity error */
					math::Vector<3> vel_err = _vel_sp - _vel;

					/* derivative of velocity error, not includes setpoint acceleration */
					math::Vector<3> vel_err_d = (_sp_move_rate - _vel).emult(_params.pos_p) - (_vel - _vel_prev) / dt;
					_vel_prev = _vel;

					/* thrust vector in NED frame */
					math::Vector<3> thrust_sp = vel_err.emult(_params.vel_p) + vel_err_d.emult(_params.vel_d) + thrust_int;

					if (!_control_mode.flag_control_velocity_enabled) {
						thrust_sp(0) = 0.0f;
						thrust_sp(1) = 0.0f;
					}

					if (!_control_mode.flag_control_climb_rate_enabled) {
						thrust_sp(2) = 0.0f;
					}

					/* limit thrust vector and check for saturation */
					bool saturation_xy = false;
					bool saturation_z = false;

					/* limit min lift */
					float thr_min = _params.thr_min;

					if (!_control_mode.flag_control_velocity_enabled && thr_min < 0.0f) {
						/* don't allow downside thrust direction in manual attitude mode */
						thr_min = 0.0f;
					}

					float tilt_max = _params.tilt_max_air;

					/* adjust limits for landing mode */
					if (!_control_mode.flag_control_manual_enabled && _pos_sp_triplet.current.valid &&
					  	_pos_sp_triplet.current.type == position_setpoint_s::SETPOINT_TYPE_LAND) {
						/* limit max tilt and min lift when landing */
						tilt_max = _params.tilt_max_land;

						if (thr_min < 0.0f) {
							thr_min = 0.0f;
						}
					}

					/* limit min lift */
					if (-thrust_sp(2) < thr_min) {
						thrust_sp(2) = -thr_min;
						saturation_z = true;
					}

					if (_control_mode.flag_control_velocity_enabled) {
						/* limit max tilt */
						if (thr_min >= 0.0f && tilt_max < M_PI_F / 2 - 0.05f) {
							/* absolute horizontal thrust */
							float thrust_sp_xy_len = math::Vector<2>(thrust_sp(0), thrust_sp(1)).length();

							if (thrust_sp_xy_len > 0.01f) {
								/* max horizontal thrust for given vertical thrust*/
								float thrust_xy_max = -thrust_sp(2) * tanf(tilt_max);

								if (thrust_sp_xy_len > thrust_xy_max) {
									float k = thrust_xy_max / thrust_sp_xy_len;
									thrust_sp(0) *= k;
									thrust_sp(1) *= k;
									saturation_xy = true;
								}
							}
						}

					} else {
						/* thrust compensation for altitude only control mode */
						float att_comp;

						if (PX4_R(_att.R, 2, 2) > TILT_COS_MAX) {
							att_comp = 1.0f / PX4_R(_att.R, 2, 2);

						} else if (PX4_R(_att.R, 2, 2) > 0.0f) {
							att_comp = ((1.0f / TILT_COS_MAX - 1.0f) / TILT_COS_MAX) * PX4_R(_att.R, 2, 2) + 1.0f;
							saturation_z = true;

						} else {
							att_comp = 1.0f;
							saturation_z = true;
						}

						thrust_sp(2) *= att_comp;
					}

					/* limit max thrust */
					float thrust_abs = thrust_sp.length();

					if (thrust_abs > _params.thr_max) {
						if (thrust_sp(2) < 0.0f) {
							if (-thrust_sp(2) > _params.thr_max) {
								/* thrust Z component is too large, limit it */
								thrust_sp(0) = 0.0f;
								thrust_sp(1) = 0.0f;
								thrust_sp(2) = -_params.thr_max;
								saturation_xy = true;
								saturation_z = true;

							} else {
								/* preserve thrust Z component and lower XY, keeping altitude is more important than position */
								float thrust_xy_max = sqrtf(_params.thr_max * _params.thr_max - thrust_sp(2) * thrust_sp(2));
								float thrust_xy_abs = math::Vector<2>(thrust_sp(0), thrust_sp(1)).length();
								float k = thrust_xy_max / thrust_xy_abs;
								thrust_sp(0) *= k;
								thrust_sp(1) *= k;
								saturation_xy = true;
							}

						} else {
							/* Z component is negative, going down, simply limit thrust vector */
							float k = _params.thr_max / thrust_abs;
							thrust_sp *= k;
							saturation_xy = true;
							saturation_z = true;
						}

						thrust_abs = _params.thr_max;
					}

					/* update integrals */
					if (_control_mode.flag_control_velocity_enabled && !saturation_xy) {
						thrust_int(0) += vel_err(0) * _params.vel_i(0) * dt;
						thrust_int(1) += vel_err(1) * _params.vel_i(1) * dt;
					}

					if (_control_mode.flag_control_climb_rate_enabled && !saturation_z) {
						thrust_int(2) += vel_err(2) * _params.vel_i(2) * dt;

						/* protection against flipping on ground when landing */
						if (thrust_int(2) > 0.0f) {
							thrust_int(2) = 0.0f;
						}
					}

					/* calculate attitude setpoint from thrust vector */
					if (_control_mode.flag_control_velocity_enabled) {
						/* desired body_z axis = -normalize(thrust_vector) */
						math::Vector<3> body_x;
						math::Vector<3> body_y;
						math::Vector<3> body_z;

						if (thrust_abs > SIGMA) {
							body_z = -thrust_sp / thrust_abs;

						} else {
							/* no thrust, set Z axis to safe value */
							body_z.zero();
							body_z(2) = 1.0f;
						}

						/* vector of desired yaw direction in XY plane, rotated by PI/2 */
						math::Vector<3> y_C(-sinf(_att_sp.yaw_body), cosf(_att_sp.yaw_body), 0.0f);

						if (fabsf(body_z(2)) > SIGMA) {
							/* desired body_x axis, orthogonal to body_z */
							body_x = y_C % body_z;

							/* keep nose to front while inverted upside down */
							if (body_z(2) < 0.0f) {
								body_x = -body_x;
							}

							body_x.normalize();

						} else {
							/* desired thrust is in XY plane, set X downside to construct correct matrix,
							 * but yaw component will not be used actually */
							body_x.zero();
							body_x(2) = 1.0f;
						}

						/* desired body_y axis */
						body_y = body_z % body_x;

						/* fill rotation matrix */
						for (int i = 0; i < 3; i++) {
							R(i, 0) = body_x(i);
							R(i, 1) = body_y(i);
							R(i, 2) = body_z(i);
						}

						/* copy rotation matrix to attitude setpoint topic */
						memcpy(&_att_sp.R_body[0], R.data, sizeof(_att_sp.R_body));
						_att_sp.R_valid = true;

						/* calculate euler angles, for logging only, must not be used for control */
						math::Vector<3> euler = R.to_euler();
						_att_sp.roll_body = euler(0);
						_att_sp.pitch_body = euler(1);
						/* yaw already used to construct rot matrix, but actual rotation matrix can have different yaw near singularity */

					} else if (!_control_mode.flag_control_manual_enabled) {
						/* autonomous altitude control without position control (failsafe landing),
						 * force level attitude, don't change yaw */
						R.from_euler(0.0f, 0.0f, _att_sp.yaw_body);

						/* copy rotation matrix to attitude setpoint topic */
						memcpy(&_att_sp.R_body[0], R.data, sizeof(_att_sp.R_body));
						_att_sp.R_valid = true;

						_att_sp.roll_body = 0.0f;
						_att_sp.pitch_body = 0.0f;
					}

					_att_sp.thrust = thrust_abs;

					/* save thrust setpoint for logging */
					_local_pos_sp.acc_x = thrust_sp(0);
					_local_pos_sp.acc_x = thrust_sp(1);
					_local_pos_sp.acc_x = thrust_sp(2);

					_att_sp.timestamp = hrt_absolute_time();


				} else {
					reset_int_z = true;
				}
			}

			/* fill local position, velocity and thrust setpoint */
			_local_pos_sp.timestamp = hrt_absolute_time();
			_local_pos_sp.x = _pos_sp(0);
			_local_pos_sp.y = _pos_sp(1);
			_local_pos_sp.z = _pos_sp(2);
			_local_pos_sp.yaw = _att_sp.yaw_body;
			_local_pos_sp.vx = _vel_sp(0);
			_local_pos_sp.vy = _vel_sp(1);
			_local_pos_sp.vz = _vel_sp(2);

			/* publish local position setpoint */
			if (_local_pos_sp_pub > 0) {
				orb_publish(ORB_ID(vehicle_local_position_setpoint), _local_pos_sp_pub, &_local_pos_sp);
			} else {
				_local_pos_sp_pub = orb_advertise(ORB_ID(vehicle_local_position_setpoint), &_local_pos_sp);
			}

		} else {
			/* position controller disabled, reset setpoints */
			_reset_alt_sp = true;
			_reset_pos_sp = true;
			_mode_auto = false;
			reset_int_z = true;
			reset_int_xy = true;
		}

		// generate attitude setpoint from manual controls
		if(_control_mode.flag_control_manual_enabled && _control_mode.flag_control_attitude_enabled) {

			// reset yaw setpoint to current position if needed
			if (reset_yaw_sp) {
				reset_yaw_sp = false;
				_att_sp.yaw_body = _att.yaw;
			}

			// do not move yaw while arming
			else if (_manual.z > 0.1f)
			{
				const float YAW_OFFSET_MAX = _params.man_yaw_max / _params.mc_att_yaw_p;

				_att_sp.yaw_sp_move_rate = _manual.r * _params.man_yaw_max;
				_att_sp.yaw_body = _wrap_pi(_att_sp.yaw_body + _att_sp.yaw_sp_move_rate * dt);
				float yaw_offs = _wrap_pi(_att_sp.yaw_body - _att.yaw);
				if (yaw_offs < - YAW_OFFSET_MAX) {
					_att_sp.yaw_body = _wrap_pi(_att.yaw - YAW_OFFSET_MAX);

				} else if (yaw_offs > YAW_OFFSET_MAX) {
					_att_sp.yaw_body = _wrap_pi(_att.yaw + YAW_OFFSET_MAX);
				}
			}

			//Control roll and pitch directly if we no aiding velocity controller is active
			if(!_control_mode.flag_control_velocity_enabled) {
				_att_sp.roll_body = _manual.y * _params.man_roll_max;
				_att_sp.pitch_body = -_manual.x * _params.man_pitch_max;
			}

			//Control climb rate directly if no aiding altitude controller is active
			if(!_control_mode.flag_control_climb_rate_enabled) {
				_att_sp.thrust = _manual.z;
			}

			//Construct attitude setpoint rotation matrix
			math::Matrix<3,3> R_sp;
			R_sp.from_euler(_att_sp.roll_body,_att_sp.pitch_body,_att_sp.yaw_body);
			memcpy(&_att_sp.R_body[0], R_sp.data, sizeof(_att_sp.R_body));
			_att_sp.timestamp = hrt_absolute_time();
		}
		else {
			reset_yaw_sp = true;
		}

		/* publish attitude setpoint
		 * Do not publish if offboard is enabled but position/velocity control is disabled,
		 * in this case the attitude setpoint is published by the mavlink app
		 */
		if (!(_control_mode.flag_control_offboard_enabled &&
					!(_control_mode.flag_control_position_enabled ||
						_control_mode.flag_control_velocity_enabled))) {
			if (_att_sp_pub > 0) {
				orb_publish(ORB_ID(vehicle_attitude_setpoint), _att_sp_pub, &_att_sp);

			} else {
				_att_sp_pub = orb_advertise(ORB_ID(vehicle_attitude_setpoint), &_att_sp);
			}
		}

		/* reset altitude controller integral (hovering throttle) to manual throttle after manual throttle control */
		reset_int_z_manual = _control_mode.flag_armed && _control_mode.flag_control_manual_enabled && !_control_mode.flag_control_climb_rate_enabled;
	}

	warnx("stopped");
	mavlink_log_info(_mavlink_fd, "[mpc] stopped");

	_control_task = -1;
	_exit(0);
}