ABE has the ability to dock to a mooring and remain in "sleep" mode to perform preprogrammed, repeatable seafloor measurements over extended periods. Low power sleep mode, docking, closed loop positioning, terrain-following, high and low-frequency acoustic navigation. Each type of vehicle has inherent attributes that make it more suitable for certain tasks than are other systems. However, because of their limitations of range and time on bottom or in the water column, which is dictated by the on-board energy source, human endurance, and the cost of support ship and crew, DSVs generally are not well suited for large area search and survey or extended observation—tasks that are most efficiently carried out by towed vehicles at present.
DSVs have been used in some cases. An example was the Challenger search when the Johnson Sea-Link I and II had a large area survey role in water depths of less than 1, meters. Large area up to sq km observation and measurement, medium geodetic or relative navigation accuracy. Relatively large area coverage, acoustic and optical sensing, object identification, good navigation.
Close-up observation, optical and other sensors, good vehicle positioning and stability. Transport and placement of toxic materials in predetermined locations. May be large quantities or a deep site. DSVs are not suitable for operating in dangerous areas, such as in tunnels or around explosives. ROVs, which are powered from the surface, have no real energy limitations. They are also generally stable. Viewing facilities for the human operator are good and continue to be improved, including stereo and new "augmented reality" compatibility.
However, due to tether drag, ROVs are limited in how far and how fast they can travel from their support craft, and they are less suitable for large area, long-range search or survey and long, under ice transits. AUVs can move rapidly and, subject to limitations of the on-board energy storage, can generally traverse great distances relative to the other two types of vehicles. This makes them well suited for transporting sensors over large areas for surveys of various kinds. Some AUV systems have used a fiber-optic communications link for all or part of their operation.
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However, this is not a routine mode of operation, and, without a tether, the communication mechanisms for real-time human intervention are limited. Nevertheless, the narrow beam acoustic links have passed at least 50, bits per second bps , and even low-bandwidth links can pass some useful data. To extend the range of AUV applications, increasingly effective autonomous work systems are evolving rapidly along with the general field of robotics. Another present AUV limitation is that data transfer must wait until the AUV vehicle is recovered on-board a mother ship. In response to this problem, acoustic telemetry schemes now emerging offer a hybrid arrangement where the human can intervene on a limited, non-real-time basis.
New advances in task-level control architecture will enable the operator to command tasks at a high-level in real-time within the new bandwidth. AUVs are limited by the current lack of maturity of task-management architecture that can be placed on-board. Overcoming this limitation is the focus of present research at the Monterey Bay Aquarium Research Institute Wang et al. Table summarizes the foregoing discussion and includes a list of generic tasks that may be performed by vehicle systems. The committee has characterized the relative abilities of the different vehicle types to carry out these tasks; several qualitative descriptors are used, each representing the collective opinions of the committee and each based on considerations such as those discussed above.
This section evaluates the state of the art and state of practice for vehicle technologies and assesses the potential for future developments. In the total system context described. For "augmented reality," the human can move an icon i. The technologies described are typically applicable to several if not all types of vehicles covered in this report. This section groups the subsystems into two categories: These two categories may overlap in some cases, but the distinction is useful for analysis. New developments with near-term usefulness are cited for each area, and the status of synergistic technology developments from other industries is discussed.
Each subsystem and its driving technologies play a role in overall vehicle performance and contribute to the vehicle's capability to accomplish specific mission objectives. Lack of development in certain technology areas inhibits progress and further applications because they determine or facilitate vehicle capabilities. The technologies in other subsystems are highly developed, and further advancement will not appreciably improve the overall performance of the system.
Accordingly, during the committee's evaluation, each subsystem was given an importance rating of "critical," "incremental," or "mature," depending on our evaluation of its impact on further vehicle development. These ratings are characterized as follows:. Critical—Improvement in the subsystem will enable or create important new vehicle capabilities. Incremental—Vehicle progress can benefit from development of subsystems technologies in an evolutionary manner.
Mature—Development has been successful and further improvement may occur, but development will contribute only marginally to improved vehicle performance, and improvements will be used only if they are cost-effective compared to current techniques. Existing energy sources pose limitations for systems without cable connections i.
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Energy limitations on AUVs are critical, and they are becoming more critical for DSVs because of the growing power demands of sensors, lights, computers, and manipulators. High-energy density batteries could lengthen missions and generally improve performance. Energy sources are rated in terms of both energy and power.
The most frequently used ratings are "specific energy" watt-hours per kilogram or "energy density" watt-hours per liter. Batteries are usually used in underwater vehicles; numerous other energy technologies are also available, but they are more costly. The performance characteristics of available energy sources are compared in Table The table is divided into four types of energy systems: Secondary batteries are electrically rechargeable, while primary batteries are used for only a single cycle.
Ag-Zn may be included in either category; in its primary configuration it may be recharged as many as five cycles, which hardly counts as rechargeable. Fuel cells are electrochemical devices that passively without heat react a fuel and an oxidizer to produce electricity; power levels are controlled by the amount of reactant injected into the cell. Many fuel cells are rechargeable, but not in the same way as secondary batteries; instead, reactant tanks are filled, and in some cases sacrificial metallic elements are replaced.
Heat engines are generally closed-cycle, air-dependent systems that react fuel and oxidant in a mechanical cycle to drive an engine, which in turn directly drives the propulsion system or a generator to support electronic equipment. Table is not intended to be all-inclusive. Instead it provides an overview of available energy technologies that can be considered for undersea vehicles.
Battery and fuel cell technologies developed for applications in space, automobile, and communications industries have not been adapted for use in undersea vehicles because of their cost, safety, immaturity in development, or incompatibility with marine missions. Cost is a primary factor and, as shown in Table , varies by orders of magnitude for different systems. Cost roughly increases as the energy density increases. These types of energy sources are found mostly in military systems where mission and endurance are primary factors that outweigh cost.
Factors important in selecting a battery include power density the ability to deliver stored energy at the rate needed , outgassing properties, failure modes, reliability, ease and speed of recharge, and ability to operate over broad temperature and pressure ranges. Considerations of safety in handling energy sources, both aboard ship and aboard the vehicle, are critical and have limited the use of some chemistries, such as lithium, despite their high energies.
Some systems give off explosive gases during operation, and others may start fires if they fail. Current battery types used in undersea vehicles include standard lead-acid and nickel-cadmium batteries as well as silver-zinc and lithium-thionyl-chloride batteries. Figure provides a helpful way to visualize the power and energy capabilities of various battery chemistries. For military applications, silver-zinc has been the de facto standard for over 20 years.
Recently lithium-thionyl-chloride see primary lithium in Figure has seen some use because of its significantly higher energy rating. Silver-zinc batteries are typically usable for 20 to 30 cycles,. The higher energy batteries hold the potential for violent release of energy under certain circumstances and are not generally used in commercial and scientific applications Harma, ; Moore, Although higher energy systems are critically important to high-endurance AUVs, cost and safety must be primary objectives as new sources are developed.
Newer secondary lithium chemistries hold the promise of reasonable production cost, high numbers of recharge cycles approaching the lifetimes of lead-acid automobile batteries , no outgassing, benign failure modes, and energy densities better than offered by silver-zinc batteries.
Development of these batteries is largely being driven by laptop computer and portable electronics applications, but they are presently being adapted to larger-scale batteries for automotive use and should be available for military and commercial undersea vehicles within three to five years. Recharging techniques for secondary batteries are being developed for a variety of user applications in the telecommunications, automotive, and undersea vehicle industries. The intent is to reduce the recharge time, extend the ratio of operating to charging time, improve battery cycle life, and promote personnel safety.
Charging techniques such as pulse charging can be used to manage the recharge process and decrease recharge time, to reduce heat generation, and to minimize cell degradation. For undersea vehicles, some new. This information is based on current Lockheed Martin Corporation programs and plans and on independent research and development related to energy sources as described in internally published documents Gentry, Other charging schemes include charging with solar cells, either by surfacing or by connecting to a subsurface charging station powered from the surface.
Other energy system developments include seawater batteries, which react metals with the oxygen dissolved in seawater. These batteries have been difficult to use because they produce very low- voltage and power due to the limited quantity of dissolved oxygen in seawater. However, efficient dc-to-dc conversion can overcome some of these limitations. Since seawater batteries depend on dissolved oxygen, these batteries also may not be suitable in some parts of the ocean, such as in hypoxic areas Blase and Bis, Military research and development efforts have explored using seawater batteries, but little work is ongoing in this area in the United States.
Metals can also be reacted with oxygen carried on-board a vehicle. An aluminum-oxygen semi-fuel cell has been built and tested at sea with some success Collins et al. ARPA is developing a higher power density version Gibbons et al. The key concerns in this technology are oxygen storage and manufacturability. Canadian companies have also developed an aluminum semi-fuel cell, which uses pumped alkaline electrolyte and oxygen sources. This energy subsystem has been tested in an AUV Stannard et al.
NASA has used alkaline fuel cells widely in spacecraft for over 20 years. One of these fuel cells was successfully demonstrated in a DSV in the late s; however, cost and logistical problems limited further development for undersea use. The newer proton exchange membrane fuel cells offer many advantages over alkaline fuel cells, including lower cost, higher power capacities, improved tolerance to impurities in the reactant gases, and better long-term cycle performance.
Energy capabilities of fuel cells are high, but they are limited by the difficulty of storing hydrogen and oxygen at high densities. The logistics of reactant handling and storage continues to make cost reductions and practical usage of fuel cells elusive. These can use conventional or hydrogen fuels in combustion cycles e.
Brayton, Stirling similar to engines developed for the transportation industry. A Stirling engine was tested successfully in an undersea vehicle by a Swedish company and is operational on-board the French Saga vehicle. They have performed significant work in wick combustors, using liquid lithium reacted with sulphur hexaflorate to create a high-temperature heat source for a Rankine or Stirling thermal engine Hughes, In an attempt to achieve a more environmentally benign, refuelable, high-energy density product which is 80 percent of the energy generated by liquid lithium , the Applied Research Laboratory at Pennsylvania State University is investigating a wick combustor fueled with JP-5 standard Navy jet fuel and a lithium perchlorate oxygen source to drive the heat engine Hughes, If successful, this approach may provide a less costly power source for AUVs in the future.
Most research and development in the field of energy storage occurs outside the undersea vehicles area. The committee anticipates that future energy system development applicable to undersea vehicles will derive mostly from the aerospace and automobile industries, where batteries and fuel cells are being evaluated for near-term use, and from the telecommunications and personal computer industries, where small-format lithium batteries are in development.
Energy systems are a low development priority for ROVs, whose performance is limited by other considerations. However, size, cost, and duration limitations related to DSVs and AUVs will be mitigated only when practical, safe, and readily available energy sources are developed. The advisability of making large investments in energy system research and development for commercial applications is questionable, and the decision must be made in the light of true development costs. Since most near-term AUV and DSV applications can be accomplished with existing and proven battery chemistries, research and development funds will be better spent in technology areas that are specifically marine, such as underwater navigation, acoustic communications, or subsea sensors.
Energy systems will be advanced by industries such as the space, automotive, and telecommunication industries that have a more immediate need for them and can obtain development capital based on large markets for their products. Most undersea vehicle thrusters now use fixed-pitch propellers driven by electric or hydraulic motors.
The propeller configurations used derive from mature technology developed for ships and boats. However, optimization of propeller efficiencies continues as new undersea vehicle designs emerge. Heavy duty ROVs at work in the offshore petroleum industry use hydraulic motors to power thrusters; power is supplied from an electrohydraulic unit mounted in the vehicle.
The pumps, motors, and valves used in system integration are largely standard commercial products. If nozzles are used on AUVs, they usually serve as propeller guards rather than as thrust enhancers. Other thruster types, such as variable pitch propellers, cycloidal devices, and water jets have been abandoned because of complexity or inefficiency Gangadharan and Krein, Oscillating foils, which function like a fish tail, are being studied and have achieved limited drag reduction Triantafyllou et al.
This concept may be applicable to AUV propulsion in the future. Another interesting new direction in propulsion for long-distance observations is using controlled buoyancy or combinations of buoyancy and thrusters to propel undersea vehicles.
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The "Slocum" for example, is a concept that would use a heat engine, drawing on the ocean thermocline to adjust the buoyancy of an AUV; wings would provide lift and limited horizontal steering Kunzig, ; Stommel, The concept offers the promise of low-cost tens of thousands of dollars, per vehicle, rather than millions ; long-range 2, km as a near-term goal ; and increased endurance 50 days. The ultimate goal is to offer a fleet of low-cost, long-range AUVs that would operate simultaneously, taking oceanographic measurements with higher spatial and temporal resolution than are available with current techniques and at substantially lower costs.
The Odyssey vehicle, described in Chapter 1 , is another low-cost vehicle that could be deployed in fleets, although it has a shorter range. The Slocum buoyancy-adjustment mechanism without lift or steering has been tested at depths to 1, meters. The system currently being developed uses a battery-powered pump to enhance buoyancy control and propulsion Webb, Propulsion systems are a mature technology and a low priority for development since existing systems are adequate—although improvements in efficiency are always useful—for most underwater vehicle applications anticipated in the next decade.
Structural materials currently used for DSVs, ROVs, and AUVs have been adapted from the submarine and shipbuilding industries as well as from advanced aerospace programs. Design approaches derive from work by ship classification organizations, such as the American Bureau of Shipping, as well as from finite-element analysis techniques used in naval architecture and in many industries.
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Thus, with the exception of full-ocean depth vehicles 11,meter depth capability , materials and design capabilities can be considered relatively mature. Improvements in materials tend to be more important for vehicles intended for deep applications because of the strength required to counter high pressures. Improvements in material are also important for applications to AUVs, where lightweight materials can be translated into energy and payload for additional range and endurance and for work or sensing capabilities that require energy.
Currently, nonmetallic materials, including filamentwound epoxies, Kevlar, and graphite composites and ceramics, are used for military applications in both primary structures pressure hulls and secondary structures fairings. However, the cost of some of these materials discourages commercial use. Ceramic alumina cylinders have been tested for pressure housings and hulls, with potential weight reductions of 85 percent compared with titanium; however, economical manufacturing techniques are still under development Stachiw, ; Kurkchubasche, , DeRoos et al.
Other ceramics being considered include silicon nitride, silicon carbide, and boron carbide materials Ashley, Advanced materials for fairings include graphite epoxy layup or fiberglass constructions using a fiber-impregnated, high-density polyethylene that is also acoustically transparent Sloan and Nguyen, AUSS uses this polyethylene material for its fairings. Advances in high quality acrylic and quartz glass will provide greater visibility to pilots of DSVs.
Developments in important materials technology for vehicles aim to provide low-cost, lightweight, high-buoyancy materials for flotation. Sandwiched composite and syntactic buoyancy materials are being used to provide lightweight, high-displacement secondary structures. Although strength, density, and buoyancy are key design factors, longevity, corrosion resistance, and reliability also affect materials selection.
Design innovations have been demonstrated during development of new structures despite the relative maturity of conventional technology in this field. The two Deep Flight vehicle prototypes for a single-occupant, free-flying, full-ocean depth DSV represent an innovation in alternatives for supporting human activity in the deep sea Hawkes and Ballou, ; Ashley, Deep Flight's pressure hulls are wound glass filament and epoxy matrix. Such a vehicle depends on advanced materials for structures to support its performance goals.
Russian and Ukrainian undersea vehicle programs have developed advanced techniques for fabricating structures of titanium, ceramic, and composite materials, according to two teams of experts who recently surveyed the undersea vehicle programs of western Europe and the former Soviet Union, under the auspices of the World Technology Evaluation Center Mooney et al. Another materials technology area of importance to system improvement is using coatings and other methods to resist biofouling or degradation of the vehicle's outer skin.
Biofouling can create dynamic drag and interfere with the performance of skin-mounted sensors. This can be an especially critical problem for long-duration missions. Conventional coating systems that are used on surface ships may not be desirable for vehicles because the toxic compounds they use to kill organisms might cause chemical contamination of the vehicle's scientific sensors. The success of most undersea vehicle applications depends on accurate navigation and positioning. Navigation is the function that continuously locates the vehicle within geodetic or relative coordinates and is critical to vehicle safety, operational productivity in real-time, and post-mission scientific and information processing.
Positioning refers to the localized and more precise measurements often used to determine specific distances relative to some fixed point. For example, vehicle work in the offshore oil and gas industry frequently involves precision measuring and positioning of equipment relative to installations on the seafloor. When operating a vehicle in a localized area, most contemporary navigation and positioning systems make use of acoustic transponders such as the long-baseline networks widely used in many types of deep water work.
Systems of this type use bottom-placed transducers in array fields with typical transponder separations of up to 4 km and can offer accuracies of 1 meter at frequencies of 26 to 36 kHz. Recent developments in acoustic positioning include a high-frequency, high-accuracy system that determines the position of a vehicle with an accuracy of a few centimeters in a bottom-placed transponder field. Other systems, which utilize transducers mounted on the surface ship and a transponder on the vehicle short baseline , do not require transponders on the seafloor. These systems are widely used for navigating vehicles relative to a support ship.
Combinations of these acoustic systems are used to maximize the advantages of each for best navigational accuracy for specific environmental conditions. Numerous other acoustic and nonacoustic sensor technologies are used on the vehicle to enhance navigation and positioning. Simple video cameras are useful, especially for ROVs and DSVs, when operating near the bottom of a structure and can provide the operator a reference for motion. Computerized image processing techniques have been developed that can use information from video cameras to navigate vehicles automatically Wang et al.
Further developments of this type will enhance the value of video as a navigation aide, especially for AUVs, where precise autonomous, near-field navigation is. These study teams included two members of this committee, J. Scanning or multibeam sonars are used to provide operators with images of obstacles and terrain in the immediate area surrounding the vehicle. These systems are very popular and have developed to the point that high-frequency, high-resolution systems are reliable and economically available on the commercial market.
Current developments in sonar and signal processing include obstacle-avoidance sonars that can construct a terrain map and guidance strategies for optimum pathfinding. Navigation over long distances or for prolonged durations is generally a requirement for AUV missions and is critical to mission success. AUV navigation systems typically use magnetic or gyro compasses and a velocity sensor to provide dead-reckoning. These systems, derived from extensive use on aircraft and spacecraft, provide inertial navigation, which is then corrected by velocity estimators and by position fixes, as available.
Estimated vehicle speed is obtained from current and flow sensors, Doppler sonars, or correlation sonars. Doppler sonar uses reflected echoes to provide highly accurate measures of motion relative to the bottom or fixed points in the water column. Doppler correlation sonars can "bottom-lock," referencing the vehicle's motion to the bottom, from altitudes of 3, meters or more. The advent of small inertial devices, such as ring laser gyros a solid-state version of the conventional rotating gyro , are making this type of navigation increasingly useful as accuracy goes up and cost goes down Moore, ; Ezekiel, The result is that velocity-aided inertial navigation systems are now available that provide accuracies on the order of 0.
As these improvements continue, costly, time consuming transponder fields will become increasingly unnecessary. The greatest advances in undersea navigation in the near future will come not from any one isolated type of system but from integration of an increasing number of systems and components.
Most of the above techniques benefit greatly from position referencing to the Global Positioning System. Recent work in the combination of inertial units with ultrashort baseline transponder systems and Doppler sonars has shown that combining sensors with different characteristics can synergistically improve navigation performance Hutchison and Skov, ; Hutchison, Accuracy on the order of 0. Navigation, guidance, and control functions are often separated for discussion, as is the case in this report.
This modularization assists in understanding the complex operating concept for undersea vehicles and is also helpful to the vehicle designer. In practice, however, these functions are highly interactive and, in fact, use many common sensors and processors.
Thus advances or improvements in one function normally are linked to advances in other functions. For example, the development of a highly accurate, long-duration navigation system would be useless without guidance and control capabilities that support mission intelligence and reliable navigational capabilities. Guidance and control of an undersea vehicle are generally implemented in a layered or hierarchical architecture. Guidance involves higher-level mission management activities, such as planning and directing vehicle movement through the water column; control operates at a lower functional level to interact with specific equipment on the vehicle.
The control level includes the closed loop functions autopilot that provide stable, controlled operation of the vehicle. The control level receives orders from guidance and, in turn, commands physical actuators, propulsors, and effectors to maneuver and operate the vehicle in a manner that accomplishes higher-level guidance objectives.
In the early days of undersea vehicle development, maneuvering depended almost exclusively on the direct manual control skills of human pilots, and all higher-level planning was accomplished by the pilot. With ROVs, pilots worked primarily from video images, using visual references to keep track of vehicle and tether location. Later, automatic heading and depth controls became common on most vehicles because of the evolution of reliable sensors, modern computing equipment, well-understood control algorithms, and efficient software.
Tracking systems, imaging sonars and inertial navigation systems also improved the human operator's ability to determine vehicle position in geodetic or local reference coordinates, thus enhancing vehicle guidance and control. Continuing improvements in navigation and control technology permit automation of all vehicle motions.
Marine engineering
A vehicle with full automation and control of movement and direction can hover for long periods and can follow preplanned track lines precisely while under "supervisory control," that is, with the human operator providing high-level, task-oriented commands rather than exercising direct control over all functions of the vehicle Yoerger and Slotine, ; Wang et al. Vehicles equipped with such capabilities have. Dead-reckoning is defined as the finding of location using compass readings and other recorded data, such as speed and distance traveled, rather than astronomical observations.
Techniques are also being developed to allow vehicles to hold position based on video, laser, and acoustic imagery and to use imagery for guidance Marks et al. Many advances in control depend on improved understanding of vehicle dynamics and improved signal processing algorithms for closing feedback loops around sensors to form servo loops Yuh, ; Healy and Leonard, ; Fossen, Future developments may extend these capabilities in several directions. Improved navigation that combines inertial and velocity measurements as described in the previous section currently being developed for military AUVs will enable precise automated vehicle motion without the need for a transponder network.
Control systems combined with sensors that detect cables, pipelines, hydrocarbon leaks, or other pollutants allow highly efficient automated tracking and surveying Greig et al. Likewise, improvements to in situ sensors for oceanographic parameters and chemical samples, combined with advanced vehicle control systems, will allow scientists to map distributions with unprecedented sampling density at reasonable cost, perhaps with multiple vehicles Triantafyllou, ; Curtin et al.
At the heart of these improvements is the ability to integrate navigation, guidance, and controls with sensors, using modern hierarchical architecture techniques to enhance accuracy, efficiency, ease of human task-level control, and reliability of vehicles for a wide range of mission needs.
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Odyssey II reached a depth of 1, meters and ran surveys designed to characterize spatial variability of temperature and salinity in three dimensions. Navigation was provided by a long-baseline acoustic navigation system. To provide an understanding about temporal evolution in the survey volume, the grid survey was preceded and followed by vehicle paths crossing the survey volume. As indicated above, developments in guidance and control, at all levels, are critical for progress in AUV applications where robust mission management is key to reliable and repeatable performance.
Artificial intelligence techniques are being applied to offer AUVs an interpretive logic capability based on processing probabilistic data. In the future, AUVs should be capable of pursuing tasks that have abstract descriptions; for example, finding and following a chemical gradient or surveying a given area with the ability to replan and reconfigure the mission based on a wide range of changing internal and external factors. Failure detection and recovery are perhaps the most critical operations and the most difficult.
The vehicle must be able to sense when one or more of its subsystems have failed and must be capable of reconfiguring its controls and replanning the mission in real-time to work around in the worst case, aborting the mission in the safest manner. The the problems; accomplishing the highest priority objectives; and vehicle must also be able to handle high-level failures such as reattempting and Bellingham, Vehicle software provides commands for a set of quasi-independent "layered" behaviors, such as "detect collision," "hold heading," or "head to way-point.
A Navy-sponsored project is developing an intelligent, fault-tolerant vehicle guidance and control system, and system testing and demonstration are planned. While much of this development is directed toward specific use by AUVs, it is supported by complementary work of the computer aerospace and automated manufacturing industries. Continuing advances in task-level control architectures and higher bandwidth communications have resulted in robots that respond directly to graphical task-level human input.
These robots use an advanced form of "telerobotics," or control from a distance, which until recently allow only a "joy stick" human interface. For many mid-water tasks the vehicle and its manipulators need to be controlled as a single moving system. The new capability called "object-based task-level control" enables the direct human command to the task that will be performed; the control system then plans and executes the task.
Because of the much lower bandwidth required for task-level commands, object-based task-level central will enable near real-time control of AUVs, which will be a powerful new capability Wang et al. Techniques for vehicle control are continuously being improved. Apart from the act of sinking, these ships are generally sheltered from human or environmental disturbance such as ground swell, backwash, and tidal movements. But, because of the dark and high-pressured environment, it is also extremely difficult for humans to gain access.
The latter requires investigative resources on an entirely different scale, which is still very largely experimental. Underwater 2D and 3D photogrammetry have become very common in the last five years and are now widely used for underwater archaeology, either with ROVs or AUVs. But, the navigation and control capacities of the robot near 3D structures still need to be improved. Standard underwater manipulator arms are used to sample ancient artefacts from the deep. Moreover, the claws of underwater manipulator arms are not very well suited to fragile archaeological artefacts.
The robotic hand is operated dry from the ship's scientific command post where the live images of the on-board cameras arrive. As part of this research, the first Speedy robot tested an omnidirectional vision system and an anthropomorphic hand with three fingers that follow the shape of the objects seized. We are developing underwater robotic hands to do just that. Most of the tests so far are conducted on the Lune shipwreck testing laboratory. Some other experiments have been carried out on deeper antic shipwrecks m and on a more modern battleship wrecked in , located 1, m deep.
With the hand and the Speedy ROV, we have collected numerous fragile artefacts from the Lune site without any damage. The DRASSM have also tested many types of robotics devices such as large claws, water jetting, crawlers, several types of lights, and several custom-made cameras. The robots need to be pressure resistant, which means that most moving mechanical parts are oil filled.
And of course, they operate in the dark so need powerful lights. Each campaign gives the opportunity for Creuze and his team to experiment and improve new tools that are developed by the LIRMM and by the companies and institutions participating in the Corsaire Concept Project. These shipwrecks cannot be excavated without robots. High to Low Avg. Available for download now.
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