Ejemplo n.º 1
0
bool MulticopterLandDetector::_get_maybe_landed_state()
{
	// Time base for this function
	const hrt_abstime now = hrt_absolute_time();

	// When not armed, consider to be maybe-landed
	if (!_arming.armed) {
		return true;
	}

	if (_has_minimal_thrust()) {
		if (_min_trust_start == 0) {
			_min_trust_start = now;
		}

	} else {
		_min_trust_start = 0;
	}

	float landThresholdFactor = 1.0f;

	// Widen acceptance thresholds for landed state right after landed
	if (hrt_elapsed_time(&_landed_time) < LAND_DETECTOR_LAND_PHASE_TIME_US) {
		landThresholdFactor = 2.5f;
	}

	// Next look if all rotation angles are not moving.
	float maxRotationScaled = _params.maxRotation_rad_s * landThresholdFactor;

	bool rotating = (fabsf(_vehicleAttitude.rollspeed)  > maxRotationScaled) ||
			(fabsf(_vehicleAttitude.pitchspeed) > maxRotationScaled) ||
			(fabsf(_vehicleAttitude.yawspeed) > maxRotationScaled);

	// Return status based on armed state and throttle if no position lock is available.
	if (!_has_altitude_lock() && !rotating) {
		// The system has minimum trust set (manual or in failsafe)
		// if this persists for 8 seconds AND the drone is not
		// falling consider it to be landed. This should even sustain
		// quite acrobatic flight.
		return (_min_trust_start > 0) && (hrt_elapsed_time(&_min_trust_start) > 8_s);
	}

	if (_ground_contact_hysteresis.get_state() && _has_minimal_thrust() && !rotating) {
		// Ground contact, no thrust and no movement -> landed
		return true;
	}

	return false;
}
bool MulticopterLandDetector::_get_ground_contact_state()
{
	// Time base for this function
	const uint64_t now = hrt_absolute_time();

	// only trigger flight conditions if we are armed
	if (!_arming.armed) {
		_arming_time = 0;
		return true;

	} else if (_arming_time == 0) {
		_arming_time = now;
	}

	// If in manual flight mode never report landed if the user has more than idle throttle
	// Check if user commands throttle and if so, report no ground contact based on
	// the user intent to take off (even if the system might physically still have
	// ground contact at this point).
	const bool manual_control_idle = (_has_manual_control_present() && _manual.z < _params.manual_stick_down_threshold);
	const bool manual_control_idle_or_auto = manual_control_idle || !_control_mode.flag_control_manual_enabled;

	// Widen acceptance thresholds for landed state right after arming
	// so that motor spool-up and other effects do not trigger false negatives.
	float armThresholdFactor = 1.0f;

	if (hrt_elapsed_time(&_arming_time) < LAND_DETECTOR_ARM_PHASE_TIME_US) {
		armThresholdFactor = 2.5f;
	}

	// Check if we are moving vertically - this might see a spike after arming due to
	// throttle-up vibration. If accelerating fast the throttle thresholds will still give
	// an accurate in-air indication.
	bool verticalMovement = fabsf(_vehicleLocalPosition.vz) > _params.maxClimbRate * armThresholdFactor;

	// If pilots commands down or in auto mode and we are already below minimal thrust and we do not move down we assume ground contact
	// TODO: we need an accelerometer based check for vertical movement for flying without GPS
	if (manual_control_idle_or_auto && _has_minimal_thrust() &&
	    (!verticalMovement || !_has_altitude_lock())) {
		return true;
	}

	return false;
}
bool MulticopterLandDetector::_get_maybe_landed_state()
{
	// Time base for this function
	const uint64_t now = hrt_absolute_time();

	// only trigger flight conditions if we are armed
	if (!_arming.armed) {
		return true;
	}

	// If we control manually and are still landed, we want to stay idle until the pilot rises the throttle for takeoff
	if (_state == LandDetectionState::LANDED && _has_manual_control_present()) {
		if (_manual.z < _get_takeoff_throttle()) {
			return true;

		} else {
			// Pilot wants to take off, assume no groundcontact anymore and therefore allow thrust
			_ground_contact_hysteresis.set_state_and_update(false);
			return false;
		}
	}

	if (_has_minimal_thrust()) {
		if (_min_trust_start == 0) {
			_min_trust_start = now;
		}

	} else {
		_min_trust_start = 0;
	}

	float landThresholdFactor = 1.0f;

	// Widen acceptance thresholds for landed state right after landed
	// so that motor spool-up and other effects do not trigger false negatives.
	if (hrt_elapsed_time(&_landed_time) < LAND_DETECTOR_LAND_PHASE_TIME_US) {
		landThresholdFactor = 2.5f;
	}

	// Next look if all rotation angles are not moving.
	float maxRotationScaled = _params.maxRotation_rad_s * landThresholdFactor;

	bool rotating = (fabsf(_vehicleAttitude.rollspeed)  > maxRotationScaled) ||
			(fabsf(_vehicleAttitude.pitchspeed) > maxRotationScaled) ||
			(fabsf(_vehicleAttitude.yawspeed) > maxRotationScaled);

	// Return status based on armed state and throttle if no position lock is available.
	if (!_has_altitude_lock() && !rotating) {
		// The system has minimum trust set (manual or in failsafe)
		// if this persists for 8 seconds AND the drone is not
		// falling consider it to be landed. This should even sustain
		// quite acrobatic flight.
		if ((_min_trust_start > 0) &&
		    (hrt_elapsed_time(&_min_trust_start) > 8000000)) {

			return true;

		} else {
			return false;
		}
	}

	if (_ground_contact_hysteresis.get_state() && _has_minimal_thrust() && !rotating) {
		// Ground contact, no thrust and no movement -> landed
		return true;
	}

	return false;
}