![MiniU](https://upload.wikimedia.org/wikipedia/commons/d/d2/MiniU.jpg)
An autonomous underwater vehicle (AUV) is a
robot
A robot is a machine—especially one programmable by a computer—capable of carrying out a complex series of actions automatically. A robot can be guided by an external control device, or the control may be embedded within. Robots may be c ...
that travels underwater without requiring input from an operator. AUVs constitute part of a larger group of undersea systems known as
unmanned underwater vehicle
Unmanned underwater vehicles (UUV), sometimes known as underwater drones, are submersible vehicles that can operate underwater without a human occupant. These vehicles may be divided into two categories: remotely operated underwater vehicles (ROU ...
s, a classification that includes non-autonomous
remotely operated underwater vehicle
A remotely operated underwater vehicle (technically ROUV or just ROV) is a tethered underwater mobile device, commonly called ''underwater robot''.
Definition
This meaning is different from remote control vehicles operating on land or in the ai ...
s (ROVs) – controlled and powered from the surface by an operator/pilot via an umbilical or using remote control. In military applications an AUV is more often referred to as an unmanned undersea vehicle (UUV).
Underwater glider
An underwater glider is a type of autonomous underwater vehicle (AUV) that employs variable-buoyancy propulsion instead of traditional propellers or thrusters. It employs variable buoyancy in a similar way to a profiling float, but unlike a flo ...
s are a subclass of AUVs.
History
The first AUV was developed at the Applied Physics Laboratory at the
University of Washington
The University of Washington (UW, simply Washington, or informally U-Dub) is a public research university in Seattle, Washington.
Founded in 1861, Washington is one of the oldest universities on the West Coast; it was established in Seattle a ...
as early as 1957 by Stan Murphy, Bob Francois and later on, Terry Ewart. The "Special Purpose Underwater Research Vehicle", or
SPURV
SPURV, or Self-Propelled Underwater Research Vehicle, was an Autonomous Underwater Vehicle built in 1957 at the University of Washington's Applied Physics Laboratory. The research and development of this vehicle was funded by the United States O ...
, was used to study diffusion, acoustic transmission, and submarine wakes.
Other early AUVs were developed at the
Massachusetts Institute of Technology
The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the ...
in the 1970s. One of these is on display in the
Hart Nautical Gallery in MIT. At the same time, AUVs were also developed in the
Soviet Union
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national ...
(although this was not commonly known until much later).
Applications
This type of underwater vehicles has recently become an attractive alternative for underwater search and exploration since they are cheaper than manned vehicles. Over the past years, there have been abundant attempts to develop underwater vehicles to meet the challenge of exploration and extraction programs in the oceans. Recently, researchers have focused on the development of AUVs for long-term data collection in oceanography and coastal management.
Commercial
The oil and gas industry uses AUVs to make detailed
maps of the seafloor before they start building subsea infrastructure; pipelines and sub sea completions can be installed in the most cost effective manner with minimum disruption to the environment. The AUV allows survey companies to conduct precise surveys of areas where traditional bathymetric surveys would be less effective or too costly. Also, post-lay pipe surveys are now possible, which includes pipeline inspection. The use of AUVs for pipeline inspection and inspection of underwater man-made structures is becoming more common.
Research
![Solar auv tavros](https://upload.wikimedia.org/wikipedia/commons/e/e6/Solar_auv_tavros.jpg)
Scientists use AUVs to study lakes, the ocean, and the ocean floor. A variety of sensors can be affixed to AUVs to measure the concentration of various elements or compounds, the absorption or reflection of light, and the presence of microscopic life. Examples include conductivity-temperature-depth sensors (CTDs),
fluorometer
A fluorometer, fluorimeter or fluormeter is a device used to measure parameters of visible spectrum fluorescence: its intensity and wavelength distribution of emission spectrum after excitation by a certain spectrum of light. These parameters ar ...
s, and
pH sensors. Additionally, AUVs can be configured as tow-vehicles to deliver customized sensor packages to specific locations.
The Applied Physics Lab at the University of Washington has been creating iterations of its ''Seaglider'' AUV platform since the 1950s. Though the
Seaglider
The Seaglider is a deep-diving Autonomous Underwater Vehicle (AUV) designed for missions lasting many months and covering thousands of miles. In military applications the Seaglider is more commonly referred to as an Unmanned Underwater Vehicle ( ...
was originally designed for oceanographic research, in recent years it has seen much interest from organizations such as the U.S. Navy or the oil and gas industry. The fact that these autonomous gliders are relatively inexpensive to manufacture and operate is indicative of most AUV platforms that will see success in myriad applications.
An example of an AUV interacting directly with its environment is the Crown-Of-Thorns Starfish Robot (
COTSBot
COTSBot is a small intelligent underwater craft long, which is designed by Queensland University of Technology (QUT) to kill the very destructive crown of thorns starfish in the Great Barrier Reef off the north-east coast of Australia. It identifi ...
) created by the Queensland University of Technology (QUT). The COTSBot finds and eradicates
crown-of-thorns starfish
The crown-of-thorns starfish (frequently abbreviated to COTS), ''Acanthaster planci'', is a large starfish that preys upon hard, or stony, coral polyps (Scleractinia). The crown-of-thorns starfish receives its name from venomous thorn-like spine ...
(''Acanthaster planci''), a species that damages the
Great Barrier Reef
The Great Barrier Reef is the world's largest coral reef system composed of over 2,900 individual reefs and 900 islands stretching for over over an area of approximately . The reef is located in the Coral Sea, off the coast of Queensland, ...
. It uses a neural network to identify the starfish and injects
bile salts
Bile acids are steroid acids found predominantly in the bile of mammals and other vertebrates. Diverse bile acids are synthesized in the liver. Bile acids are conjugated with taurine or glycine residues to give anions called bile salts.
Primary b ...
to kill it.
Hobby
Many roboticists construct AUVs as a hobby. Several competitions exist which allow these homemade AUVs to compete against each other while accomplishing objectives. Like their commercial brethren, these AUVs can be fitted with cameras, lights, or sonar. As a consequence of limited resources and inexperience, hobbyist AUVs can rarely compete with commercial models on operational depth, durability, or sophistication. Finally, these hobby AUVs are usually not oceangoing, being operated most of the time in pools or lake beds. A simple AUV can be constructed from a microcontroller,
PVC pressure housing, automatic door lock actuator,
syringe
A syringe is a simple reciprocating pump consisting of a plunger (though in modern syringes, it is actually a piston) that fits tightly within a cylindrical tube called a barrel. The plunger can be linearly pulled and pushed along the inside ...
s, and a
DPDT
In electrical engineering, a switch is an electrical component that can disconnect or connect the conducting path in an electrical circuit, interrupting the electric current or diverting it from one conductor to another. The most common type of ...
relay. Some participants in competitions create designs that rely on open-source software.
Illegal drug traffic
Submarines that travel autonomously to a destination by means of GPS navigation have been made by illegal drug traffickers.
Air crash investigations
Autonomous underwater vehicles, for example
AUV ABYSS, have been used to find wreckage of missing airplanes, e.g.
Air France Flight 447
Air France Flight 447 (AF447 or AFR447) was a scheduled international passenger flight from Rio de Janeiro, Brazil, to Paris, France. On 1 June 2009, inconsistent airspeed indications led to the pilots inadvertently stalling the Airbus A330 ser ...
, and the
Bluefin-21 AUV was used in the search for
Malaysia Airlines Flight 370
Malaysia Airlines Flight 370 (MH370/MAS370) was an international passenger flight operated by Malaysia Airlines that disappeared on 8 March 2014 while flying from Kuala Lumpur International Airport in Malaysia to its planned destination ...
.
Military applications
![Mk 18 Mod 2 UUV launch from rigid-hull inflatable boat](https://upload.wikimedia.org/wikipedia/commons/1/14/Mk_18_Mod_2_UUV_launch_from_rigid-hull_inflatable_boat.JPG)
The U.S. Navy Unmanned Undersea Vehicle (UUV) Master Plan identified the following UUV's missions:
* Intelligence, surveillance, and reconnaissance
* Mine countermeasures
* Anti-submarine warfare
* Inspection/identification
* Oceanography
* Communication/navigation network nodes
* Payload delivery
* Information operations
* Time-critical strikes
The Navy Master Plan divided all UUVs into four classes:
* Man-portable vehicle class: 25–100 lb displacement; 10–20 hours endurance; launched from small water craft manually (i.e.
Mk 18 Mod 1 Swordfish UUV
* Lightweight vehicle class: up to 500 lb displacement, 20–40 hours endurance; launched from
RHIB
A rigid inflatable boat (RIB), also rigid-hull inflatable boat or rigid-hulled inflatable boat (RHIB), is a lightweight but high-performance and high-capacity boat constructed with a rigid hull bottom joined to side-forming air tubes that are i ...
using launch-retriever system or by cranes from surface ships (i.e.
Mk 18 Mod 2 Kingfish UUV
* Heavyweight vehicle class: up to 3,000 lb displacement, 40–80 hours endurance, launched from submarines
* Large vehicle class: up to 10 long tons displacement; launched from surface ships and submarines
In 2019, the Navy ordered five
''Orca'' UUVs, its first acquisition of unmanned submarines with combat capability.
Vehicle designs
Hundreds of different AUVs have been designed over the past 50 or so years, but only a few companies sell vehicles in any significant numbers. There are around 10 companies that sell AUVs on the international market, including
Kongsberg Maritime
Kongsberg Maritime (KM) is a Norwegian technology enterprise within the Kongsberg Gruppen (KOG). Kongsberg Maritime deliver systems for positioning, surveying, navigation, and automation to merchant vessels and offshore installations. Their most ...
, HII (formerly Hydroid, and previously owned by Kongsberg Maritime)
["KONGSBERG acquires Hydroid LLC"](_blank)
''Kongsberg - Hydroid'', 2007),
Bluefin Robotics,
Teledyne Gavia (previously known as Hafmynd),
International Submarine Engineering
International is an adjective (also used as a noun) meaning "between nations".
International may also refer to:
Music Albums
* ''International'' (Kevin Michael album), 2011
* ''International'' (New Order album), 2002
* ''International'' (The T ...
(ISE) Ltd,
Atlas Elektronik
Atlas Elektronik is a naval/marine electronics and systems business based in Bremen, Germany. It is involved in the development of integrated sonar systems for submarines and heavyweight torpedoes.
The company was a subsidiary of BAE Systems ...
, RTsys and OceanScan.
Vehicles range in size from man portable lightweight AUVs to large diameter vehicles of over 10 metres length. Large vehicles have advantages in terms of endurance and sensor payload capacity; smaller vehicles benefit significantly from lower logistics (for example: support vessel footprint; launch and recovery systems).
Some manufacturers have benefited from domestic government sponsorship including Bluefin and Kongsberg. The market is effectively split into three areas: scientific (including universities and research agencies), commercial offshore (offshor energy, marine minerals etc.) and defence related applications (mine countermeasures, battle space preparation). The majority of these roles utilize a similar design and operate in a cruise (torpedo-type) mode. They collect data while following a preplanned route at speeds between 1 and 4 knots.
Commercially available AUVs include various designs, such as the small
REMUS 100 AUV originally developed by
Woods Hole Oceanographic Institution
The Woods Hole Oceanographic Institution (WHOI, acronym pronounced ) is a private, nonprofit research and higher education facility dedicated to the study of marine science and engineering.
Established in 1930 in Woods Hole, Massachusetts, it i ...
in the US and now produced commercially by HII; the HUGIN Family of AUVs comprising HUGIN, HUGIN Edge, HUGIN Superior and HUGIN Endurance developed by Kongsberg Maritime and
Norwegian Defence Research Establishment
The Norwegian Defence Research Establishment (''Forsvarets forskningsinstitutt'' – ''FFI'') is a research institute that conducts research and development on behalf of the Norwegian Armed Forces and provides expert advice to political and mi ...
; the Bluefin Robotics vehicles; the ISE Ltd. Explorer; Cellula Robotics' Solus LR; the RT Sys Comet and NemoSens AUVs; Teledyne's Gavia, Osprey and SeaRaptor; and the L3 Harris Ocean Server Iver range of AUVs.
Most AUVs fall into the survey class or cruising AUVs, in a cylindrical or torpedo shape with a powered propeller. This is seen as the best compromise between size, usable volume, hydrodynamic efficiency and ease of handling. There are some vehicles that make use of a modular design, enabling components to be changed easily by the operators. Some recent developments move away from the traditional cylindrical shape in favour of other arrangements such as Saab's Sabretooth hybrid R/AUV or the recently launched HUGIN Edge. These either optimise the shape according to the operational requirements (Sabretooth) or to benefit from low drag hydrodynamic performance (HUGIN Edge).
The market has matured since 2010 with greater emphasis on data than on vehicle characteristics. Operators are more technically aware and the utilisation of AUVs has increased commensurately. More operators use their systems autonomously, rather than supervising the vehicles using an acoustic link. Consequently, on-board processing and in-mission autonomy have become more important features for AUVs. Most AUVs have what is considered navigational or event-based autonomy. They will follow a geographic mission plan with distinct events to operate sensors, change course or return to the surface. Some AUVs have adaptive autonomy, for example the ability to adjust course to avoid obstacles along the planned route. The current state of the art is a vehicle that collects, processes and acts on the data it has acquired without operator input.
As of 2008, a new class of AUVs are being developed, which mimic designs found in nature. Although most are currently in their experimental stages, these
biomimetic
Biomimetics or biomimicry is the emulation of the models, systems, and elements of nature for the purpose of solving complex human problems. The terms "biomimetics" and "biomimicry" are derived from grc, βίος (''bios''), life, and μίμησ ...
(or
bionic
Bionics or biologically inspired engineering is the application of biological methods and systems found in nature to the study and design of engineering systems and modern technology.
The word ''bionic'', coined by Jack E. Steele in August 1 ...
) vehicles are able to achieve higher degrees of efficiency in propulsion and maneuverability by copying successful designs in nature. Two such vehicles are
Festo
Festo is a German automation company based in Esslingen am Neckar, Germany. Festo produces and sells pneumatic and electrical control systems and drive technology for factories and process automation. Festo Didactic also offers industrial edu ...
's AquaJelly (AUV)
["AquaJelly"]
''Festo Corporate'', 2008 and the
EvoLogics BOSS Manta Ray.
Sensors
AUVs carry sensors to navigate autonomously and map features of the ocean. Typical sensors include
compass
A compass is a device that shows the cardinal directions used for navigation and geographic orientation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself with ...
es, depth sensors,
sidescan and other
sonar
Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigation, navigate, measure distances (ranging), communicate with or detect o ...
s,
magnetometer
A magnetometer is a device that measures magnetic field or magnetic dipole moment. Different types of magnetometers measure the direction, strength, or relative change of a magnetic field at a particular location. A compass is one such device, o ...
s,
thermistor
A thermistor is a type of resistor whose resistance is strongly dependent on temperature, more so than in standard resistors. The word thermistor is a portmanteau of ''thermal'' and ''resistor''.
Thermistors are divided based on their conduction ...
s and conductivity probes. Some AUVs are outfitted with biological sensors including
fluorometer
A fluorometer, fluorimeter or fluormeter is a device used to measure parameters of visible spectrum fluorescence: its intensity and wavelength distribution of emission spectrum after excitation by a certain spectrum of light. These parameters ar ...
s (also known as
chlorophyll
Chlorophyll (also chlorophyl) is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Greek words , ("pale green") and , ("leaf"). Chlorophyll allow plants to a ...
sensors),
turbidity
Turbidity is the cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality.
Fluids can ...
sensors, and sensors to measure
pH, and amounts of
dissolved oxygen
Oxygen saturation (symbol SO2) is a relative measure of the concentration of oxygen that is dissolved or carried in a given medium as a proportion of the maximal concentration that can be dissolved in that medium at the given temperature. It ca ...
.
A demonstration at
Monterey Bay
Monterey Bay is a bay of the Pacific Ocean located on the coast of the U.S. state of California, south of the San Francisco Bay Area and its major city at the south of the bay, San Jose. San Francisco itself is further north along the coast, by a ...
, in California, in September 2006, showed that a diameter AUV can tow a -long hydrophone array while maintaining a cruising speed.
Navigation
Radio waves cannot penetrate water very far, so as soon as an AUV dives it loses its GPS signal. Therefore, a standard way for AUVs to navigate underwater is through
dead reckoning
In navigation, dead reckoning is the process of calculating current position of some moving object by using a previously determined position, or fix, and then incorporating estimates of speed, heading direction, and course over elapsed time. ...
. Navigation can however be improved by using an
underwater acoustic positioning system
An underwater acoustic positioning system is a system for the tracking and navigation of underwater vehicles or divers by means of acoustic distance and/or direction measurements, and subsequent position triangulation. Underwater acoustic position ...
. When operating within a net of sea floor deployed baseline transponders this is known as
LBL navigation. When a surface reference such as a support ship is available,
ultra-short baseline
USBL (ultra-short baseline, also known as SSBL for super short base line) is a method of underwater acoustic positioning. A USBL system consists of a transceiver, which is mounted on a pole under a ship, and a transponder or responder on the seaf ...
(USBL) or
short-baseline (SBL) positioning is used to calculate where the sub-sea vehicle is relative to the known (
GPS
The Global Positioning System (GPS), originally Navstar GPS, is a Radionavigation-satellite service, satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of t ...
) position of the surface craft by means of acoustic range and bearing measurements.
To improve estimation of its position, and reduce errors in dead reckoning (which grow over time), the AUV can also surface and take its own GPS fix.
Between position fixes and for precise maneuvering, an
Inertial Navigation System
An inertial navigation system (INS) is a navigation device that uses motion sensors (accelerometers), rotation sensors ( gyroscopes) and a computer to continuously calculate by dead reckoning the position, the orientation, and the velocity (dire ...
on board the AUV calculates through dead reckoning the AUV position, acceleration, and velocity. Estimates can be made using data from an
Inertial Measurement Unit
An inertial measurement unit (IMU) is an electronic device that measures and reports a body's specific force, angular rate, and sometimes the orientation of the body, using a combination of accelerometers, gyroscopes, and sometimes magnetometer ...
, and can be improved by adding a
Doppler Velocity Log
An acoustic Doppler current profiler (ADCP) is a hydroacoustic current meter similar to a sonar, used to measure water current velocities over a depth range using the Doppler effect of sound waves scattered back from particles within the water col ...
(DVL), which measures the rate of travel over the sea/lake floor. Typically, a pressure sensor measures the vertical position (vehicle depth), although depth and altitude can also be obtained from DVL measurements. These observations are
filtered
Filtration is a physical separation process that separates solid matter and fluid from a mixture using a ''filter medium'' that has a complex structure through which only the fluid can pass. Solid particles that cannot pass through the filter m ...
to determine a final navigation solution.
Propulsion
There are a couple of propulsion techniques for AUVs. Some of them use a brushed or brush-less electric motor, gearbox,
Lip seal
Radial shaft seals, also known as lip seals, are used to seal rotary elements, such as a shaft or rotating bore. Common examples include strut seals, hydraulic pump seals, axle seals, power steering seals, and valve stem seals. Early radial sh ...
, and a propeller which may be surrounded by a nozzle or not. All of these parts embedded in the AUV construction are involved in propulsion. Other vehicles use a
thruster unit to maintain the modularity. Depending on the need, the thruster may be equipped with a nozzle for propeller collision protection or to reduce noise submission, or it may be equipped with
direct drive thrusterto keep the efficiency at the highest level and the noises at the lowest level. Advanced AUV thrusters have a redundant shaft sealing system to guarantee a proper seal of the robot even if one of the seals fails during the mission.
Underwater gliders do not directly propel themselves. By changing their buoyancy and trim, they repeatedly sink and ascend;
airfoil
An airfoil (American English) or aerofoil (British English) is the cross-sectional shape of an object whose motion through a gas is capable of generating significant lift, such as a wing, a sail, or the blades of propeller, rotor, or turbine.
...
"wings" convert this up-and-down motion to forward motion. The change of buoyancy is typically done through the use of a pump that can take in or push out water. The vehicle's pitch can be controlled by changing the center of mass of the vehicle. Fo
Slocum glidersthis is done internally by moving the batteries, which are mounted on a screw. Because of their low speed and low-power electronics, the energy required to cycle trim states is far less than for regular AUVs, and gliders can have endurances of months and transoceanic ranges.
Communications
Since radio waves do not propagate well under water, many AUV's incorporate Acoustic Modems to enable remote command and control. These modems typically utilize proprietary communications techniques and modulation schemes. In 2017 NATO ratified the ANEP-87 JANUS standard for subsea communications. This standard allows for 80 BPS communications links with flexible and
extensible message formatting
Power
Most AUVs in use today are powered by rechargeable batteries (
lithium ion
A lithium-ion or Li-ion battery is a type of rechargeable battery which uses the reversible reduction of lithium ions to store energy. It is the predominant battery type used in portable consumer electronics and electric vehicles. It also se ...
,
lithium polymer
A lithium polymer battery, or more correctly lithium-ion polymer battery (abbreviated as LiPo, LIP, Li-poly, lithium-poly and others), is a rechargeable battery of lithium-ion technology using a polymer electrolyte instead of a liquid electrolyt ...
,
nickel metal hydride
Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow to r ...
etc.), and are implemented with some form of
Battery Management System. Some vehicles use primary batteries which provide perhaps twice the endurance—at a substantial extra cost per mission. Previously some systems used aluminum based semi-
fuel cell
A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most batteries in requ ...
s, but these require substantial maintenance, require expensive refills and produce waste product that must be handled safely. An emerging trend is to combine different battery and power systems with
supercapacitor
A supercapacitor (SC), also called an ultracapacitor, is a high-capacity capacitor, with a capacitance value much higher than other capacitors but with lower voltage limits. It bridges the gap between electrolytic capacitors and rechargeable ba ...
s.
See also
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References
Bibliography
* Technology and Applications of Autonomous Underwater Vehicles Gwyn Griffiths
* Review of Autonomous Underwater Vehicle (AUV) Developments
* Masterclass in AUV Technology for Polar Science
* The Operation of Autonomous Underwater Vehicles2
* 1996 Symposium on Autonomous Underwater Vehicle Technology
* Development of an Autonomous Underwater Vehicle
* Optimal Control System for A Semi-Autonomous Underwater Vehicle
* Autonomous Underwater Vehicles
* Recommended Code of Practice for the Operation of Autonomous Marine Vehicles
* Autonomer Mobiler Roboter
* Remotely operated underwater vehicle
* Underwater Robots
* The World AUV Market Report 2010-2019
* Autonomous Underwater Vehicles: Design and practice
External links
First AUV to cross Atlantic Ocean Displayed at SmithsonianPresentation of the AUV Abyss (IFM-GEOMAR Kiel)The Application of Autonomous Underwater Vehicle (AUV) Technology in the Oil Industry – Vision and Experiences
{{DEFAULTSORT:Autonomous Underwater Vehicle
Vehicles introduced in 1957