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UUVs—submersible unmanned vehicles—are divided into two categories: remotely operated underwater vehicles (ROVs) and autonomous underwater vehicles (AUVs). ROVs are controlled and powered by a person or crew on either land or neighboring craft via an umbilical or using remote control. The truly autonomous AUV systems are typically deployed from a research vessel, they are not tethered to the vessel and do not require direct human control while collecting data. It is often preprogrammed with waypoints and a designated task and when it finishes its mission, it returns to a preprogrammed location. Its data and information is then gathered and dowloaded for further analysis. Modern autonomous underwater vehicle (AUV) is an intelligent unmanned platform to perform a variety of military and civilian missions in complex marine environment, which can better meet the needs, such as scientific research, military operations and commercial applications.
Future naval battles will rely heavily on advantages gained through the combination of strategies, tactics, procedures, and technologies called network-centric warfare.
An AUV is a underwater robot that operates in six degrees of freedom (6DOF) and can conduct planned missions by using its own propulsion system controlled by an on board computer. The payload of an AUV includes, beside the CPU and the electro-energetic system, different types of sensors and technology like navigation, system and communication.
UUVs are broken into four classes, based on their displacements. The two larger classes (as defined by the 2004 UUV Master Plan) of Heavy Weight Vehicle (HWV) (21-inch diameter and less than 3000 pounds of displacement) and Large Vehicle (greater than 26-inch diameter and
approximately 20,000 pounds of displacement). Additionally, unmanned system complexity is a factor of the level of autonomy, which can range between human operated and fully autonomous.
The Navy needs a system for launching and recovering UUVs that are of a variety of sizes, weights, and shapes from a variety of ship , USV or submarine platforms. Currently, launch and recovery of AUVs from an unmanned surface vehicle (USV) requires human participation, either in the form of direct placement and retrieval from the water or by manual activation from the platform. Navies are now looking to develop automated launch and recovery systems will determine the safest methods for removing human operators from the process.
The limitation on the physical space and maintenance routines on board a submarine make L&R from submarine a greater challenge. One of the method is Launch without Recovery. Under this scenario UUV system is launched via a torpedo tube, missile tube, or dry-deck shelter will allow for covert deployment of one or more UUVs while avoiding the drawbacks associated with space considerations to support organizational level maintenance and technical risks of torpedo tube recovery. Upon mission completion, the UUV could either be abandoned or recovered by use of a support ship.
L&R Systems are required to be capable of repeatable launch and recovery under many different environmental conditions, demonstrated through in-water testing. L&R systems are required to be robust and repeatable and ensure proper restraint of UUVS during capture, interfacing, and retrieval. The critical technologies are mechanical design and interfacing, sensing and controls for smooth and controlled docking.
Our UUV launch and recovery technologies being developed are automated systems for unmanned underwater vehicles to larger vessels (both manned and unmanned).
Navy Requirements of UUV launch and Recovery systems
UUVs are off-board vehicles that are typically cylindrical or semi-cylindrical in cross section and can range in size from a small, hand-launched system such as the Woods Hole Oceanographic Institute (WHOI) REMUS 100 to large systems such as the HUGIN 3000 and REMUS 6000.
UUVs can be designed to be free-flooding or hermetically sealed, but often their shells are not adequate for lifting or grappling purposes. They often have easily damaged external features such as fins, propulsors, propellers, and antennas. Different manufacturers design different features for lifting including nose lift, tail lift, single-point body lift, and two-point body lift. Many UUVs are not designed to be driven or piloted through the water; they operate on a point-to-point system, diving underwater to transit via Inertial Navigation System (INS)/Inertial Measuring Unit (IMU) to a location where they surface to acquire the Global Positioning System (GPS) for a location fix. Many UUVs are equipped with forward looking or bottom mapping sonars that make interfacing with these areas difficult. Current commercial launch and recovery systems are often ship specific and UUV/AUV specific.
Institutions such as WHOI and private industries supporting the petroleum industry all use UUVs/Autonomous Underwater Vehicles (AUVs) and conduct numerous launch and recovery operations every year.
Pier-side launch and recovery of UUVs is relatively simple as large cranes or davits can be used to lower or recover UUVs in sheltered bays, inlets, waterways. There is often unlimited overhead and the launch/recovery system is not in motion. With underway launch and recovery aboard a ship, the ship may be transiting to maintain heading and minimize ship motions. The ship may be hovering to allow the UUV to be lowered or lifted from a fixed location. The ship may be stationary but not hovering, in which case the ship will be driven by wind and waves, often causing the ship to heave, roll, sway, and yaw. The launch and recovery system will likewise be in motion at the same time the UUV will be in motion, often with a different frequency, phase, and magnitude. The UUV will not necessarily be aligned to the same heading as the ship, or be able to be commanded to do so.
Many UUVs do not have tow points allowing them to be put undertow by the ship for launch or recovery. The goal of this design is to provide flexibility of capability and interfaces that will support a variety of UUVs (in various sea states). This should take into consideration the design constraints associated with UUVs such as easily damaged components (e.g., fins, propellers/propulsors, external antennas), hull/shell strength, hard points/lift points, and UUVs that cannot be driven/piloted like a boat (i.e., they only operate by underwater movement from GPS coordinate to GPS coordinate).
The Navy has an objective to launch and recover UUVs in sea states through sea state 3 in accordance with STANAG 4194:1983. Supported platforms potentially could have a freeboard anywhere from near the waterline to as high as 15’ above the waterline. Both variants of the LCS as well as the Expeditionary Fast Transport (EPF) ship utilize stern launch and recovery of watercraft, versus using a moon pool or side mounted launch and recovery system.
A common approach to stern launch a UUV from a ship is to bring the ship to a standstill, deploy the handling system and lower the UUV to the water’s edge before releasing it. Depending upon whether the UUV is suspended or captive, a towline can be rigged to ensure the UUV maintains a suitable orientation relative to the ship and to the horizon.
Once the UUV is clear of the ship, it can begin its functional mission. Other methods include slowing the ship to a minimal speed at which steerage can be maintained, and towing the UUV as it enters the water. The current process to recover a UUV depends upon the approach.
Web page searches will show multiple approaches from underbelly lift for small UUVs (REMUS 100), nose tow up a ramp (HUGIN 3000), and vertical recovery (REMUS 6000) using an A-frame stern launch and recovery system. WHOI developed a Launch and Recovery System (LARS) specific to the REMUS 6000.
“The REMUS Launch and Recovery System has made over 1,000 successful launch and recoveries to date. Due to the vehicle’s larger size, this self-contained system has been engineered here at WHOI in the OSL. It enables the L & R of the vehicle in sea states up to those created by the Beaufort Scale 5 winds. It requires only one operator and, therefore, does away with the need to use tag lines eliminating extra people on deck and creating a safer working environment.
LARS is installed on the stern of a ship. For launch, the LARS has a built-in A-frame, which tilts the cradle up and over, while leaving the vehicle hanging by its nose well clear of the fantail. The cradle supports the vehicle during A-frame rotation, stabilizing the vehicle until it is a safe distance from the stern. The docking head provides damping to reduce swing in heavy seas. The vehicle is then lowered into the water, tail first, while the ship is making approximately 1-2 knots forward way (this allows the vehicle to stay well clear of the ships screws). All systems are given one final checkout before release. When ready, the vehicle is commanded to release its tow-line and begin its mission.”
Likewise, from the same website, the LARS for the REMUS 3000 is described as follows: “The REMUS 3000 Launch and Recovery system, similar to the proven system of our REMUS-6000 which has completed over 1,000 successful launch and recoveries to date, has a footprint of 5.5′ x 10′. The control consists of a tilt A-frame, tilt docking head, pay in/out winch and rotate vehicle. This system enables the launch and recovery system of the AUV to be simple, reliable, easy to operate and time-saving with the hydraulics operating at 10-15 HP with a built-in joystick controls in a waterproof operator console. The system is vessel dependent and is mounted on the stern of a ship. It allows the vehicle to be operated from a vessel in sea states up to those generated by the Beaufort Scale 5 winds.”
The HUGIN 1000 can be installed in a 20-foot ISO container, which is used for storage, maintenance, launch, and recovery. According to the Kongsberg website, the HUGIN 1000 and launch device (stern ramp) can be deployed from the 20-foot ISO container from the stern of a ship. Typically, the largest challenge is to align the ship to a stationary UUV, secure a suitable lifting or towing apparatus to the UUV, and then lifting or towing the UUV from the water. Since UUVs can roll, approaches such as a v-shaped ramp or underbelly netting are generally not going to be acceptable approaches to lifting a wide range of UUVs because so many cannot afford to roll over or have fins/propellers take strain from lifting systems.
Lifecycle costs will be reduced by having a single ship that can perform multiple functions/missions with UUVs, all while using a single LARS. Likewise, savings can be realized in the use of a common LARS across various ship and shore platforms. Cost savings can be realized through reduced need for spares/use of common spares; standardized technical support services and manuals; savings through larger purchase quantities; commonality of materials and fluids. Additionally, a common handling system can be used as design criteria for future UUVs allowing them to integrate to a single system, versus developing a unique approach for every new UUV before the Navy or other users have an opportunity to influence interfaces and design. Proposers need to mindful that, if applicable, the development of supporting software must be done in an open architecture environment to facilitate maximum compatibility with future system iterations.
GLSV received a US Navy Phase-II SBIR to develop a modular, adjustable system to launch and recover UUVs (unmanned underwater vehicles) from the Freedom and Independence-class LCS ships. The recovery system will utilize a common platform that is deployed using the ship stern overhead crane. GLSV has developed an innovative strategy for UUV release and capture mechanisms, and the device is adjustable to accommodate a wide variety of UUVs of different sizes and characteristics. GLSV’s system will provide the Navy with a fast-tempo launch and recovery capability during rough seas, up to Sea State-3.
Thales Australia and Flinders University to develop automated launch and recovery system
Thales Australia and Flinders University have entered into a partnership to investigate the development of an automated launch and recovery system for the Bluefin 9 AUVs (automated underwater vehicles) that have been acquired by the Royal Australian Navy as part of its its Deployable Mine Counter Measures program.
Thales Australia will act as the design authority, working with key stakeholders to ensure that all capability and safety requirements that will enable Royal Australian Navy personnel to execute missions safely are met. Flinders University, an authority in marine environments and autonomy and a key academic partner in the recently announced $15 million TAS-CRC (Trusted Autonomous Systems Cooperative Research Centre) project, will provide subject matter expertise to investigate potential concepts for the Automatic Launch and Recovery System from a USV.
Troy Stephen, Director of Thales Underwater Systems, commented: “The concept of Automatic Launch and Recovery Systems from a USV would revolutionise the current method of deployment. Not only would it completely remove the person from the minefield but it could eliminate many of the current limitations of Unmanned Underwater Vessels (UUVs), such as transit time, battery drain, communications and mission risk. The automation of this process will provide a significant enhancement to the Navy’s capability.”
“This study is an important step forward in Navy’s transition towards autonomy; particularly in the field of mine countermeasures with its defined phases of Detection, Classification, Identification and Neutralisation. The complexity of this shift requires genuine partnership and collaboration between Defence, Industry and Academia and we’re pleased to be working with Flinders University on this crucial study.”
Professor Robert Saint, Deputy Vice-Chancellor (Research) at Flinders University, said: “As a research leader in autonomous marine vehicle systems, we look forward to contributing to strengthening Australia’s sovereign defence capabilities by developing and applying advanced imaging, guidance and control technology for unmanned underwater vehicles engaged in mine counter measure activities. This will open the way to keeping manned vessels and personnel out of dangerous minefields.”
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