Unmanned
Aircraft
Types of automation used for various unmanned
aircraft today can vary greatly. The
operator might be “in the loop” or “on the loop” depending on the systems
design. Military UAV applications
continue to research and integrate greater levels of automation then in any other
industry.
UAV
Capabilities
The greatest advancement in terms of unmanned
automated flight pertaining to automatic takeoff and landing would be the X-47B
experimental demonstrator by Northrop Grumman.
The unmanned combat air vehicle was designed to show the ability of
landing on an aircraft carrier autonomously.
In addition, the aircraft also demonstrated the ability to refuel during
autonomous flight. The basic concept
behind the unmanned combat aerial vehicle is the capability to be launched by
the click of a button. The unmanned
carrier-launched surveillance and strike system requires superior processing
power and immense amounts of data in order to make split second decisions
during all flight phases.
The difference between the X-47B and other
UAV’s with autonomous capabilities is that the X-47B does not need to be
piloted by remote control. Control of
the UAV is carried out through a forearm-mounted box called the Control Display
Unit (CDU) shown in figure 1, which sends orders to an on-board computer (TechBlog. 2013). The CDU can also be used for taxiing the UAV
on the aircraft carrier. The CDU is not
used to fly the UCAV but for sending commands such as targets, waypoints, path
corrections, and any other information that will allow the UCAV to calculate its
course and navigate utilizing the autopilot system (Rutherford, H. 2013). GPS and collision avoidance sensors are also integrated
to help with sense and avoid capabilities. Accelerometers, altimeters, gyroscopes, and
other classified hardware were also designed and integrated to provide an
advanced level of autonomous flight (Dillow, C. 2012). The system was tested through thousands of simulated
flights prior to actual flight.
Advantages of the X-47B include the ability
to launch from naval carriers unlike the predator and repaper drones, which are
too slow and large to allow such a takeoff.
In addition, the other drones currently used by the military are mostly
landed via joystick and video feed which would be an incredible challenge to
land on a carrier even for the most experienced pilot (Dillow, C. 2012). Landing an aircraft on a carrier is a complex task,
which normally requires human-to-human voice communication to verbally report out
on altitude, fuel, and other pertinent information (Dillow, C. 2012). The X-47B autonomous landing procedures have
automated almost all of the previous verbal communication. The information such as position, speed, and
pitch are sent over a datalink to the tower. Datalink failures are a possibility as well so
the system was designed to fly past the carrier during approach, find an
alternative landing location, or worst-case ditch in the ocean (Dillow, C. 2012).
Figure
1 – Forearm mounted CDU controller for X-47B.
Adapted from http://www.techeblog.com/index.php/
UAV
Limitations
The tested capabilities of the UCAV meet all
expectations an autonomous UAV should live up to. However, the capabilities are limited to the
specific conditions tested since the program is strictly experimental. During flight test, similar issues of
communication and maintenance were experienced as are with most remotely
piloted vehicles. The idea behind the demonstrator
is to show the fully autonomous capabilities and potentially use the technology
in other fighter platforms and new UAV designs.
The fact that the operator is on the loop versus in the loop can lead to
challenges if the aircraft performs in a way not intended but can’t be immediately
taken control of by an operator or pilot.
Costs of programs such as this UCAV are high
and have a specified timeline, which can sometime limit full development
potential of a new technology or system.
Manned
Aircraft
Automated operations of
manned aircraft are usually found in commercial transport through the use of
autopilot on commercial airliners which give the pilot more of a supervisory
role. In terms of manned aircraft, auto-takeoff
is not a technology or operating procedure normally used. However, auto landing of an aircraft is more common,
especially in poor visibility weather conditions.
Manned
Capabilities
Aircraft such as the Boeing 737, 777, 787
and other Airbus aircraft all come standard with a variation of autoland. More recently, autoland was demonstrated in
General Aviation through the Diamond aircraft DA42 four-seat twin-engine
airplane shown in Figure 2.
The idea behind the automatic landing feature
of the Diamond aircraft is more of a general “electronic parachute” for general
aviation pilots. General Aviation
accidents are more common then commercial operations. Some aircraft have actual parachutes that can
be deployed, others allow for pilots to release themselves, and some have no
fail safe at all. The fly by wire autoland
system is designed as an emergency backup if a pilot experiences an engine
failure or becomes incapacitated (Horne, T. 2015). The
system activates if the aircraft is near its destination and no inputs from the
pilot have been detected. Through the
use of GPS navigation and radar altimeter the system utilizes autopilot and
control power changes to extend the landing gear, flaps, and actually land the
airplane (Horne, T. 2015).
The autoland feature is a true advancement
in automation for general aviation safety.
Whether the pilot is not capable to land the aircraft, visibility is limited,
or weather conditions are poor the autoland provides an automated
solution. The autoland can be overridden
at anytime as well, allowing the pilot to take back control. In addition to the autoland feature, Diamond
is also planning to test an automatic takeoff option (Horne, T. 2015).
Figure
2 – Diamond Aircraft – Left, Cockpit view during autoland flight - Right. Adapted from http://www.avweb.com/avwebflash/news/Video-Diamond-DA42-Autoland-224897-1.html
Manned
Limitations
The autoland feature
for the Diamond aircraft is great for specific situations but is still very
limited in its applications. The
autoland doesn’t include any other autopilot features during normal flight. Autothrottle is only applied during the
engagement of the autoland feature. Also
the cost of the system is very high in comparison to the overall cost of the
aircraft, making the benefit less desirable to the average general aviation
pilot.
Conclusion
Take-off and landing are the most critical
part of any flight and the level of automation associated with this flight phase
should be based on the environment.
Unmanned platforms can take greater advantage of automatic take-offs and
landings especially in military applications.
Auto takeoff and landing allows the reduction in launch and recovery
teams, equipment, infrastructure, and maintenance. Automated take offs and landings would allow a
reduction in cost for military applications.
Take-off and landing via a joystick and video feed is very challenging
and requires a high degree of skill and situational awareness. Full autonomous takeoff and landing of UAV’s
have come a long way but still require testing for all unique flight environments,
fail safe modes, electromagnetic interference, latency, and datalink management.
Manned aircraft with capability for
automated take-offs and landings are not used as predominately and are meant as
a means of assisting the crew. During
poor visibility and bad weather, autoland is a great asset. Heavily relying on such automation is not recommended. The crew is in command of the airplane, not
the automation. Take off and landing are
critical and pilots should be in control during these phases unless other
environmental circumstances are present.
Lastly, regardless of the level of
automation and how it might be used, training is crucial. The crew must understand the automated
systems capabilities, when it should be used, and the limitations.
References
Dillow, C. (2012). I am warplane. Retrieved from http://www.popsci.com/technology/article/2012-07/i-am-warplane
Grady, M.
(2015). Diamond DA42
Autoland. Retrieved from http://www.avweb.com/avwebflash/news/Video-Diamond-DA42-Autoland-224897-1.html
Horne, T.
(2015). Diamond Debuts Autoland
System. Retrieved from https://www.aopa.org/news-and-media/all-news/2015/september/22/diamond-debuts-autoland-system?WT.mc_id=150925epilot=WT.mc_sect%3dtts#.VgU9Dbl3OKc.mailto
Nasr, Reem.
(2015). Autopilot: What the
system can and cant do. Retrieved from http://www.cnbc.com/2015/03/26/autopilot-what-the-system-can-and-cant-do.html
Rutherford,
H. (2013). The unmanned combat air system demonstrator X-47B. Chips, 31(2),
30.
TechBlog. (2013).
X-47B Stealth Drone Completes Successful Launch Aircraft Carrier. Retrieved from http://www.techeblog.com/index.php/tech-gadget/x-47b-stealth-drone-completes-successful-launch-from-aircraft-carrier
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