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An autonomous ocean vehicle is a mobile system whose
ability to accomplish a specific mission depends on the
design and interplay among its seven principal subsystems: propulsion, sensors, energy, navigation, communication, control, and autonomy. The subsystems are
coupled; a change in one impacts all the others in some
way. The operating environment for an ocean vehicle
is spatially complex, transient, and uncertain. The need
for long duration measurements and the constraints of
low bandwidth and intermittent communication dictate
autonomous capability. Large-scale, three-dimensional,
simultaneous coverage of the ocean requires concurrent
deployment of multiple vehicles. Under such conditions, cooperative, adaptive vehicle behavior provides
a competitive advantage in accomplishing most missions. Of the hundreds of types of unmanned ocean
vehicles that have been built, only a few are viable,
commercial products. Recent advances in component
technologies and subsystem performance have combined to establish new thresholds of capability that are
attractive and practical for many missions. This trend is
likely to continue. The goal of Part B is to document
the current state-of-the-art in some key areas and chart
directions for future research and development.
Propulsion is clearly a distinguishing feature of
mobile platforms. For subsurface vehicles, mechanical
forces and buoyancy forces are the two prime movers.
Propellers have dominated mechanical propulsion and
are a mature technology, which is not reviewed here.
There have been significant advances in biomimetic
propulsors, which have great advantages for maneuverability. Chapter 11 reviews biology-inspired systems
within a unifying framework of self-regulating nonlinear dynamics. Subsurface vehicles driven by buoyancy
forces (gliders) have seen explosive growth in recent
years. Chapter 12 reviews the underlying principles of
ocean gliders, in which the net hydrodynamic force of
lift and drag produced by a wing balances the net buoyancy. Various classes of gliders are categorized and new
innovative designs are described.
Ocean surface vehicles play an important and
unique role in an autonomous ocean sampling network by providing connectivity at the air-sea interface. Such connectivity includes near-surface sensing,
communication links, energy re-supply, and carrying
aircraft and subsurface vehicles. In the evolution of
autonomous surface vehicles, there has been a tendency to simply adapt existing vessels, designed for
other purposes, by removing the crew. Chapter 13
examines the characteristics of surface vehicles specifically designed for autonomous operation from the keel
up, and discusses the potential of and need for such
multi-functional platforms in an autonomous system of
systems.
Precise navigation is essential for mobile platforms
and is particularly challenging underwater. Improvements in performance in recent years are related to
reduction in the cost and size of component sensors,
and advances in algorithms such as simultaneous localization and mapping and cooperative positioning.
Chapter 14 reviews the state-of-the-art in estimating
the precise position of an autonomous ocean vehicle.
The degree of autonomy of an ocean vehicle is inversely related to the continuity and handshaking of
its communication link. Communication with an autonomous ocean vehicle is necessary to both acquire
data and/or modify its behavior. Radio, sound, and
light waves each have advantages and disadvantages in
specific applications. Chapter 15 focuses on acoustic
channel characteristics and modulation schemes used
to provide wireless connection between nodes operating underwater. Networking protocols and peer-peer
routing are important enablers for cooperative, adaptive
behavior of multiple vehicles.
Onboard energy is always a limitation for autonomous ocean vehicles, as it is for all mobile vehicles.
Efficient energy management is a function of subsystem
duty cycles, payload demand, and operating technique.
One approach is to design a vehicle to carry all the
energy it needs to complete its intended mission (e.g.,
a nuclear submarine). This approach puts a premium
on high-energy density power sources and tends toward
large displacement hull forms for long duration missions. An alternative approach is to treat energy as a distributed resource in the operational domain (caches,
renewable sources, replenishment vehicles, ambient kinetic energy advection), and plan missions to include
re-supply and/or ambient exploitation. Most mature
transportation systems use a distributed approach with
some type of supporting infrastructure. Common features of re-supply are localization of the mobile vehicle
relative to an energy source and physical connection
(docking) to enable transfer. Chapter 16 reviews advances and trade-offs inherent in autonomous ocean
vehicle docking.
Autonomous ocean vehicles are tools for intervention and/or data acquisition. One useful class of
intervention is based on manipulators. Manipulation
is a mature technology on tethered, remotely operated
vehicles. The use of manipulators on autonomous platforms is more challenging. Chapter 17 reviews recent
progress in autonomous manipulation. Data acquisition
is a function of sensor payload, which determines the
An autonomous ocean vehicle is a mobile system whose
ability to accomplish a specific mission depends on the
design and interplay among its seven principal subsystems: propulsion, sensors, energy, navigation, communication, control, and autonomy. The subsystems are
coupled; a change in one impacts all the others in some
way. The operating environment for an ocean vehicle
is spatially complex, transient, and uncertain. The need
for long duration measurements and the constraints of
low bandwidth and intermittent communication dictate
autonomous capability. Large-scale, three-dimensional,
simultaneous coverage of the ocean requires concurrent
deployment of multiple vehicles. Under such conditions, cooperative, adaptive vehicle behavior provides
a competitive advantage in accomplishing most missions. Of the hundreds of types of unmanned ocean
vehicles that have been built, only a few are viable,
commercial products. Recent advances in component
technologies and subsystem performance have combined to establish new thresholds of capability that are
attractive and practical for many missions. This trend is
likely to continue. The goal of Part B is to document
the current state-of-the-art in some key areas and chart
directions for future research and development.
Propulsion is clearly a distinguishing feature of
mobile platforms. For subsurface vehicles, mechanical
forces and buoyancy forces are the two prime movers.
Propellers have dominated mechanical propulsion and
are a mature technology, which is not reviewed here.
There have been significant advances in biomimetic
propulsors, which have great advantages for maneuverability. Chapter 11 reviews biology-inspired systems
within a unifying framework of self-regulating nonlinear dynamics. Subsurface vehicles driven by buoyancy
forces (gliders) have seen explosive growth in recent
years. Chapter 12 reviews the underlying principles of
ocean gliders, in which the net hydrodynamic force of
lift and drag produced by a wing balances the net buoyancy. Various classes of gliders are categorized and new
innovative designs are described.
Ocean surface vehicles play an important and
unique role in an autonomous ocean sampling network by providing connectivity at the air-sea interface. Such connectivity includes near-surface sensing,
communication links, energy re-supply, and carrying
aircraft and subsurface vehicles. In the evolution of
autonomous surface vehicles, there has been a tendency to simply adapt existing vessels, designed for
other purposes, by removing the crew. Chapter 13
examines the characteristics of surface vehicles specifically designed for autonomous operation from the keel
up, and discusses the potential of and need for such
multi-functional platforms in an autonomous system of
systems.
Precise navigation is essential for mobile platforms
and is particularly challenging underwater. Improvements in performance in recent years are related to
reduction in the cost and size of component sensors,
and advances in algorithms such as simultaneous localization and mapping and cooperative positioning.
Chapter 14 reviews the state-of-the-art in estimating
the precise position of an autonomous ocean vehicle.
The degree of autonomy of an ocean vehicle is inversely related to the continuity and handshaking of
its communication link. Communication with an autonomous ocean vehicle is necessary to both acquire
data and/or modify its behavior. Radio, sound, and
light waves each have advantages and disadvantages in
specific applications. Chapter 15 focuses on acoustic
channel characteristics and modulation schemes used
to provide wireless connection between nodes operating underwater. Networking protocols and peer-peer
routing are important enablers for cooperative, adaptive
behavior of multiple vehicles.
Onboard energy is always a limitation for autonomous ocean vehicles, as it is for all mobile vehicles.
Efficient energy management is a function of subsystem
duty cycles, payload demand, and operating technique.
One approach is to design a vehicle to carry all the
energy it needs to complete its intended mission (e.g.,
a nuclear submarine). This approach puts a premium
on high-energy density power sources and tends toward
large displacement hull forms for long duration missions. An alternative approach is to treat energy as a distributed resource in the operational domain (caches,
renewable sources, replenishment vehicles, ambient kinetic energy advection), and plan missions to include
re-supply and/or ambient exploitation. Most mature
transportation systems use a distributed approach with
some type of supporting infrastructure. Common features of re-supply are localization of the mobile vehicle
relative to an energy source and physical connection
(docking) to enable transfer. Chapter 16 reviews advances and trade-offs inherent in autonomous ocean
vehicle docking.
Autonomous ocean vehicles are tools for intervention and/or data acquisition. One useful class of
intervention is based on manipulators. Manipulation
is a mature technology on tethered, remotely operated
vehicles. The use of manipulators on autonomous platforms is more challenging. Chapter 17 reviews recent
progress in autonomous manipulation. Data acquisition
is a function of sensor payload, which determines the