Long-range autonomous underwater vehicle and operating method thereof

Abstract

The present document discloses a long-range autonomous underwater vehicle (AUV) for transporting, deploying and retrieving underwater payload and logistic support to seabed nodes and sub-sea assets, that combines the capability of precise hovering and relative positioning for deploying, retrieving and seabed assets operation support, namely charging and data collection, and underwater gliding for efficient long range locomotion, by using a combination of locomotion and hovering thrusters, control surfaces and variable-buoyancy control for both the gliding and transporting, deploying and retrieving underwater payloads, comprising one or more gliding surfaces, one or more propulsion thrusters, one or more hovering thrusters, two or more variable buoyancy ballast tanks, and electronic data processor configured to: adjusting the one or more gliding surfaces and the one or more variable buoyancy ballast tanks for underwater gliding; actuating the one or more propulsion thrusters, and the one or more hovering thrusters for deploying the underwater payload; and actuating the one or more propulsion thrusters, and the one or more hovering thrusters for retrieving the underwater payload. It is further disclosed an operating method of said long-range AUV.

Description

D E S C R I P T I O NLONG-RANGE AUTONOMOUS UNDERWATER VEHICLE AND OPERATING METHOD THEREOFTECH NICAL FIELD

[0001] The present disclosure relates to a long-range autonomous underwater vehicle, and operating method thereof, namely for logistic support of remote seabed, or water column, monitoring infrastructures, including precise deployment and retrieving cargo or payload, energy, and communication support.BACKGROU ND

[0002] The deployment and installation of monitoring equipment in the deep-sea seabed is typically done using large research / working vessels and dropping or winching the monitoring systems to the seabed. When a precise or accurate positioning of the equipment is required in the seabed or in the case of more sensitive and delicate equipment, a working class remotely operated vehicle (ROV) is typically used to assist the process. This adds considerable extra costs with working ROV usage and associated specialized operators, as well as with the required vessel to support that operation.

[0003] SMD commercializes a range of working-class ROVs [2] ranging from the lightweight Atom ROV to the QTrencher trenching ROV and the heavy-duty Quantum, that can interface with the latest tools, instruments, and cameras to provide customers with the flexibility they need. They incorporate highly reliable, high- performance components that utilize the latest advanced distributed control systems and dynamic positioning technologies, offering improved stability and increased usable deck space by being purposefully designed wider and lower than the competition. Although these systems are customizable to accommodate specialist requirements, they still need a vessel with a launch and recovery system as well as an umbilical cord for energy, control, and data transfer, and an operator onboard the vessel.

[0004] An alternative approach is to use systems like the Turtle robotic landers, developed by INESC TEC [3], that can have a large payload of sensors installed, andthat can move efficiently in the vertical axis, changing its buoyancy, becoming heavy or light, and in that way moving down or up in the water column. This, combined with its eight motors, allows complete control of the motion of the platform, not only in the vertical direction but also in the horizontal plane in a local area. This allows the precise positioning of the sensor's payload on the seabed and easy retrieval without the need of a working class ROV. However, this solution still requires a support vessel to transport the monitoring systems to the area of operation and some crane / winch capable of deploying them to the water.

[0005] In recent years, many marine surveys were conducted, which significantly promoted the development of marine observation equipment. Many institutes have launched their related products, such as slocum glider [3] by Woods Hole Oceanographic Institution, sea-wing glider [4] by Shenyang Institute of Automation, CAS and SOLO [5] float developed at the Scripps Institution of Oceanography, all this kind of vehicles have months endurance. Monterey Bay Aquarium Research Institute launched Tethys class AUV [6], with 300m working depth and about 120 kilograms. The National Oceanography Centre of Southampton developed Autosub LR AUV [7] [8] with 6000m working depth and with more weight. Long Range AUVs (LR-AUVs) which, unlike underwater gliders, are propeller driven. Thus, LR-AUVs combine the mobility and variable speed typical of conventional AUVs with low-power sensor payloads and energy management to extend their ra nge / e nd u rance in a similar manner to gliders.

[0006] Sea-Whale 2000 is a 3 m long, 2000 m depth-rated hybrid AUV with a nominal range of 1500 km at 0.5 m / s supporting a low-power payload of up to 7 W, including a CTD and ADCP [9], A buoyancy engine and internal moving mass enables the vehicle to undertake a glider-like sawtooth profile or operate like a conventional AUV using the propeller and control surfaces. The inclusion of a buoyancy engine enables the Sea- Whale to minimise its net buoyancy at any depth reducing the power required to maintain depth

[0010] , Sea-Whale 2000 has demonstrated week-long deployments operating in two modes, profiling and constant depth (Qju et al., 2020), and has superior range characteristics as compared with existing propeller-driven AUVs.

[0007] In 2023, the UK National Oceanography Centre designed and operated the Autosub Long Range 1500, the latest vehicles to join the Autosub family of AUVs.Unlike conventional AUVs, the ALR1500 has been developed for unaccompanied multimonth operations beyond visual line of sight

[0011] , This low-carbon technology consists of a highly capable autonomous submarine that can deliver data for scientific research, environmental monitoring, meeting licensing requirements, and undertaking industry surveys at a fraction of the cost of using specialist ships.

[0008] Cellula Robotics developed Solus-XR

[0012] , a fuel cell-powered extra-large uncrewed underwater vehicle (XLUUV) platform designed for the port-to-port, lightly supervised surveillance missions over long ranges. Solus-XR is intended to be deployed solo or in fleets to provide a persistent at-sea capability with inter-vehicle communications and adaptive missions. Solus-XR is built using an ultra-reliable and cost-effective commercial AUV survey core architecture, with the ability to carry defense or commercial payloads in its large removable payload modules. However, Solus-XR is unable to deploy the cargo accurately, much less recover it.

[0009] Despite the advanced technology developments worldwide, there are still data communication constraints and energy limits present in all these solutions. Usually, it is necessary for the system to emerge from the water in order to charge as well as for data transfer.

[0010] The current operational landscape presents several challenges in the deployment and management of underwater systems. Key among these challenges is the necessity for a support vessel capable of deploying working class Remotely Operated Vehicles (W-ROV) or Autonomous Underwater Vehicles (AUVs), contributing to high operational costs stemming from vessel expenses, W-ROV costs, and the employment of ROV operators. Moreover, missions are often of short duration, amplifying the reliance on support vessels for energy and data transfer, while simultaneously exacerbating the carbon footprint associated with these operations. Another significant hurdle lies in the deployment and retrieval of autonomous robotic landers which necessitates the presence of a support vessel. Furthermore, existing systems struggle with autonomy, as they are unable to cover long distances independently, accurately deploy systems, or retrieve previously deployed equipment. These limitations are compounded by the bulky and heavy nature of the vehiclesinvolved, further complicating operational efficiency and flexibility in underwater exploration and research endeavours.

[0011] These facts are disclosed in order to illustrate the technical problem addressed by the present disclosure.GENERAL DESCRIPTION

[0012] The present document discloses a long-range autonomous underwater vehicle (AUV) for transporting, deploying and retrieving underwater payloads and logistic support to subsea assets, capable of precise hovering and relative positioning for deploying, retrieving and seabed assets support operation and underwater gliding for long range motion, using variable-buoyancy control for both the gliding and transporting, deploying and retrieving underwater payloads, comprising one or more gliding surfaces, one or more propulsion thrusters, one or more hovering thrusters, two or more variable buoyancy ballast tanks, and an electronic data processor configured to carry out, in any order, the steps of: adjusting the one or more gliding surfaces and one or more of the two or more variable buoyancy ballast tanks for underwater gliding and optionally adjusting the AUV buoyancy to put it neutral with changes in water density or when releasing or retrieving some payload; actuating the one or more propulsion thrusters, and the one or more hovering thrusters for deploying the underwater payload; and actuating the one or more propulsion thrusters, and the one or more hovering thrusters for retrieving the underwater payload.

[0013] The disclosure includes the transport, deployment and retrieving of underwater payloads, with the use of buoyancy variation capabilities (in particular, higher buoyancy variation capabilities) associated to the combination of thrusters, allowing for both efficient gliding or standard motions, as well precise positioning, and trimming buoyancy after deployment or retrieving underwater payloads or in water densities changes.

[0014] In an embodiment, in order to enable the transport of payloads to the seabed, which are never completely neutral in terms of buoyancy, the vehicle comprises abuoyancy adaptation capability significantly greater than that typically required for gliding operations. The buoyancy variation control is configured to allow adjustment both for compensating the weight of the payload and for enabling gliding, wherein the required variation may reach several hundreds of kilograms. Traditionally, buoyancy variation systems are used solely for gliding and for minor buoyancy adjustments (trimming), in order to maintain neutral buoyancy with depth.

[0015] The disclosure includes a long-range autonomous underwater vehicle (AUV) for transporting, deploying and retrieving underwater payloads and logistic support to subsea assets, capable of precise hovering and relative positioning for deploying, retrieving and seabed assets operation support (charging and data collection) and underwater gliding for long range motion, using variable-buoyancy control for both the gliding and transporting, deploying and retrieving underwater payloads, comprising one or more gliding surfaces, one or more propulsion thrusters, one or more hovering thrusters, two or more variable buoyancy ballast tanks, and an electronic data processor configured to carry out, in any order, the steps of: adjusting the one or more gliding surfaces and one or more of the two or more variable buoyancy ballast tanks for underwater gliding and adjusting the AUV buoyancy to put it neutral with changes in water density or when releasing or retrieving some payload; actuating the one or more propulsion thrusters, and the one or more hovering thrusters for deploying the underwater payload; and actuating the one or more propulsion thrusters, and the one or more hovering thrusters for retrieving the underwater payload.

[0016] In an embodiment, the two or more variable buoyancy ballast tanks are interconnected for the passage of a fluid between the two or more variable buoyancy ballast tanks for simultaneously pitching the AUV and for varying the buoyancy of the AUV.

[0017] In an embodiment, the electronic data processor is further configured to deactivate the one or more propulsion thrusters and the one or more hovering thrusters when underwater gliding. Alternatively, the electronic data processor may be further configured to activate the one or more propulsion thrusters when underwater gliding with gliding, in particular for optimising a predetermined motion objective.

[0018] In an embodiment, the propulsion thrusters, one or more (preferably four), are mostly aligned with the vehicle's preferred locomotion direction. The hovering thrusters allow control of the AUV in the other degrees of freedom, enabling movement in sway, heave, yaw, pitch, and optionally in roll. This can be achieved using between four and sixteen thrusters arranged in different configurations, with a preferred configuration comprising eight thrusters.

[0019] In an embodiment, the electronic data processor is further configured for varying the buoyancy of the two or more variable buoyancy ballast tanks when deploying or retrieving the underwater payload in order to stabilise AUV buoyancy. This is advantageous for avoiding large variations in buoyancy that could generate an abrupt acceleration of the AUV. When retrieving some object from seabed, the electronic data processor is further configured for first grabbing the object then increase buoyancy to became neutral with the new payload. And when releasing assets in the seabed, the electronic data processor is configured to do the opposite process.

[0020] In an embodiment, the electronic data processor is further configured for varying the buoyancy of the two or more variable buoyancy ballast tanks for trimming the AUV buoyancy to put it equal to the AUV weight to be neutral in the water.

[0021] In an embodiment, the electronic data processor is further configured for gradually changing between said operation modes (gliding, hovering, deploying, retrieving).

[0022] In an embodiment, the long-range AUV further comprises spatial sensors and / or navigational sensors, namely passive and active acoustic detectors, visual detectors, camera, sonar, scanning sonar, multibeam echosounder, side-scan sonar, structured light sensor, inertial measurement unit (I MU), doppler velocity log (DVL), pressure sensor, or a combination of any of these.

[0023] In an embodiment, the long-range AUV further comprises a one or more hydrophones to detect and locate and track eventual vehicles at surface that can pose a risk for the AUV when surfacing.

[0024] In an embodiment, the long-range AUV comprises a high bandwidth optical modem and / or an acoustic modem for communication, e.g., with seabed devices or a set of external sensors.

[0025] In an embodiment, the one or more gliding surfaces comprise at least a pair of fins with a fixed part and a controllable / adjustable part, thus optimizing energy consumption.

[0026] In an embodiment, the long-range AUV further comprises a bidirectional wireless charger for inductive coupling, i.e., for electrically charging underwater devices / equipment, for charging a seabed node, preferably when hovering, in particular an underwater sensor. Alternatively, or additionally, the long-range AUV further comprises bidirectional wireless communications for communicating with underwater devices / equipment, for transferring data with a seabed node, preferably when hovering, in particular an underwater sensor.

[0027] In an embodiment, the bidirectional wireless charger is placed at the bottom of the long-range AUV or in a separated tethered platform extension.

[0028] In an embodiment, the long-range AUV comprises at least one energy harvester, preferably a solar panel on the top of the vehicle, wave power generator, a thermoelectric generator (TEG), e.g., a Seebeck generator, a turbine to harvest energy from a moving water flow, or a combination of these.

[0029] In an embodiment, the long-range autonomous underwater vehicle (AUV) is pre-equipped with cargo before entering the water.

[0030] It is further disclosed a method of operating the long-range autonomous underwater vehicle (AUV) for underwater gliding by variable-buoyancy control and / or combining with thruster, for transporting, deploying and retrieving underwater payload, the method comprising the steps, in any order, the steps of : adjusting one or more gliding surfaces and one or more variable buoyancy ballast tanks for underwater gliding; actuating one or more propulsion thrusters, and one or more hovering thrusters for deploying the underwater payload; one or more variable buoyancy ballast tanks for optionally compensating the changes in weight when releasing or retrievingsome underwater payload; and actuating one or more propulsion thrusters, and one or more hovering thrusters for retrieving the underwater payload.

[0031] The gliding locomotion by the gliding surfaces may be combined with propulsion thrusters, and / or the gliding locomotion by the gliding surfaces may be combined with hoovering thrusters.

[0032] In an embodiment, deploying the underwater payload comprises lowering it via a drone extension, winching a mechanical / magnetic release / catching device, or directly placing it on the seabed using an articulated arm. Thus, eliminating the need for surface vessels and associated Working class ROVs or traditional transportation methods, streamlining logistics, drastically cutting logistics-associated costs and minimizing environmental impact.

[0033] In an embodiment, retrieving the payload comprises hoisting or catching the underwater payload.

[0034] In an embodiment, the method of operating the long-range AUV comprises a first step of retrieving the underwater payload from a first georeferenced site and a subsequent step of deploying the underwater payload on a second georeferenced site.

[0035] In an embodiment, the first and second georeferenced sites identify an underwater location up to 6000m of depth or a location in the water column.

[0036] In an embodiment, the method of operating the long-range AUV comprises a step of receiving sensor data from spatial sensors, navigational sensors, and / or external underwater sensors, e.g., an underwater device.

[0037] In an embodiment, the method of operating the long-range AUV comprises a step of establishing a data link via a bidirectional wireless connection with an external underwater sensor, preferably the bidirectional wireless connection is an optical, acoustic, or electromagnetic wireless connection.

[0038] In an embodiment, the method of operating the long-range AUV comprises a step of establishing an inductive coupling between the long-range AUV and an underwater device for supplying electrical power to the underwater device and / or between the long-range AUV and an external power supplier, e.g., a platform orunderwater docking station, for supplying electrical power to the long-range AUV.Thus, enhancing the underwater device operational capabilities and longevity.

[0039] In an embodiment, the underwater payload is at least one of: a secondary AUV (one or more smaller AUVs), one or more seabed nodes, underwater equipment, an underwater cable, or a cable array.

[0040] In an embodiment, the method further comprising a step of landing at a seabed, i.e. bottoming in a seabed, and entering an ultra-low power hibernation mode.

[0041] In an embodiment, the method further comprising a step of harvesting energy, in particular using vertical turbines, when hibernated in the landed position in a seabed.

[0042] In an embodiment, the method comprising a step of harvesting energy when at surface by solar energy and / or wave energy.

[0043] In an embodiment, the method comprising a step of harvesting energy when gliding with the retractable vertical generator extended down.BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The following figures provide preferred embodiments for illustrating the disclosure and should not be seen as limiting the scope of invention.

[0045] Figures 1A-1D: Schematic representations, in a lateral cross section and top view, of an embodiment of a long-range autonomous underwater vehicle.

[0046] Figure 2: Schematic representation of an embodiment of a long-range autonomous underwater vehicle with a central section for transporting cargo opened and closed.

[0047] Figure 3: Schematic representation of the method for transporting cargo to remote underwater locations.

[0048] Figure 4: Schematic representation of an embodiment of a long-range autonomous underwater vehicle transporting smaller AUVs.

[0049] Figure 5: Schematic representation of a long-range autonomous underwater vehicle with a solar cell cover.

[0050] Figure 6: Schematic representation of a long-range autonomous underwater vehicle with turbines for energy harvesting.

[0051] Figure 7: Schematic representation of the path of the long-range autonomous underwater vehicle when gliding.DETAILED DESCRIPTION

[0052] A long-range autonomous underwater vehicle with the capacity to transport, deploy, and retrieve other systems to the deep-sea seabed, covering long distances and depths (typically, up to 6000 m, though it can be deeper). The AUV also gives support to the deployed systems through charging and data transfer, thus extending their permanence at sea. This opens the possibility for long-term monitoring operations of deep and remote locations without requiring very expensive support vessels in permanent operations.

[0053] Figure 1A shows a schematic representation, in a lateral cross section 110 and a top view 120, of an embodiment of a long-range autonomous underwater vehicle, wherein 100 represents a front section of the long-range AUV, 200 represents a front variable buoyancy system (VBS), 300 represents a central section for transporting cargo, 201 represents a back VBS, and 400 represents a back section of the long-range AUV.

[0054] In the top view it is possible to see the two spheres belonging to the VBS in each of the segments 200 and 201.

[0055] In an embodiment, the front section of the long-range AUV 100 supports an electronic data processor, e.g., a computer, and it further comprises spatial sensors (e.g., front looking sonar, scanning sonar, multibeam and sidescan), navigationsupporting sensors (e.g., IMU, DVL, or pressure sensor).

[0056] In an embodiment, the variable buoyancy ballast tanks, herein also named variable buoyancy system, comprises an oil tank, membranes bladers, pumps and valves.

[0057] In an embodiment, the central section for transporting cargo 300 comprises a at least a pair of fins for gliding and a door for controlling the opening of a deployment / recover system, i.e., acting as an internal storage system.

[0058] In an embodiment, the back section of the long-range AUV 400 comprises propulsion thrusters, herein also named as longitudinal thrusters, and directional and vertical control surfaces.

[0059] Figure IB shows a zoom in the front section of the long-range AUV 100 in a lateral cross section, wherein 101 represents a front looking sonar, 102 represents a scanning sonar, 103 represents a multibeam, 104 represents a computational cylinder, 105 represents a Sidescan / SAS, 106 represents IMU and a pressure sensor, 107 represents a DVL, and 109 represents cameras and a Structured Light Sensor (SLS).

[0060] Figure 1C shows a zoom in the back section of the long-range AUV 400 in a lateral cross section, wherein 401 represents vertical control surface, 403 represents a direction control surface, and 405 represents a propulsion thruster.

[0061] In an embodiment, the vertical control surface comprises at least a pair of fins with a fixed part and a controllable / adjustable part.

[0062] Figure ID shows a zoom in the front variable buoyancy system 200 in a lateral cross section to the left and a top view to the right, wherein 401 represents an oil tank, 402 represents a membrane bladder, 403 represents a set of pumps, valves internal pressure sensors and VBS control electronics, 404 represents lateral and / or vertical thrusters (hovering thrusters), 405 represents an energy storage, 406 represents an energy management system, e.g., a dedicated electronic microcontroller. Hovering thrusters combined with propulsion thrusters enable six degrees of freedom control (surge, sway, heave, roll, pitch and yaw).

[0063] In an embodiment, a VBS is positioned in two sections of the vehicle 200, 201. First, the high relation of buoyancy variation capability to the total weight of the VBS allows for scaling the buoyancy variation and adapting it to transportation needs moreefficiently. Second, using two interconnected VBS in the front 200 and back 201 of the vehicle enables it to be used simultaneously to pitch the AUV up and put it buoyant or down and heavy. Combined with the shape and the fins surfaces, this provides a gliding capability that allows ultra-energy-efficient travel of very long distances.

[0064] The interconnection from the front 200 and back VBS 201, allows for the possibility to pump oil between those allowing to adjusting pitch with less energy consumption. This is possible because the alternative would be to increase the buoyancy in one and decrease in the other, but in that way, and since the external pressure is much higher than the internal pressure, the energy consumption in pumping oil out (more or less proportional to the external pressure) would be several times higher than to pump between the VBS tanks.

[0065] The combination of the gliding capabilities, longitudinal thrusters, control surfaces, and arrangement of lateral / vertical thrusters allows both the efficient long travelling for transportation of equipment to remote locations, e.g., over 1000 km, and hovering / precise positioning underwater near seabed enabling the deployment and recovering of the equipment to / from the seabed or water column and / or collect data (e.g., using high bandwidth optical modems or acoustic modems) and / or providing power using bidirectional wireless energy transfer modules.

[0066] In an embodiment, the variable buoyancy system comprises several functionalities such as: allows compensation of total buoyancy of the AUV - In deployment and recover operations - by pumping oil from deposit to / from external bladder; allow to became buoyant to move upward gliding - pumping from oil deposits to external bladder; allows to became heavy to move downward gliding - pumping oil from external bladder to oil deposits; and allows pitch and roll control - by transferring from front to back or from left to right.

[0067] Figure 2 shows a schematic representation of an embodiment of a long-range autonomous underwater vehicle with a central section for transporting cargo 300 opened and closed, wherein 301 represents controllable door for opening / closing thedeployment / recover system, 303 represents an internal storage system, and 305 represents a fin for gliding.

[0068] In an embodiment, the fins for gliding 305 are retractable.

[0069] Figure 3 shows a schematic representation of the method for transporting cargo to remote underwater locations, wherein 501 represents a drone extension for deployment or recovering farther from the AUV into the seabed, and 502 represents an alternative embodiment for deploying / recovering a cargo directly from the seabed with a simpler manipulation device, and 503 an alternative embodiment for deploying / recovering a cargo by winching a mechanical / magnetic release / catching device.

[0070] In an embodiment, the drone extension 501 allows for energy charging of a seabed device.

[0071] Figure 4 shows a schematic representation of an embodiment of a long-range autonomous underwater vehicle transporting smaller AUVs.

[0072] Figure 5 shows a schematic representation of a long-range autonomous underwater vehicle with a solar cell cover, wherein 503 represents a thin-film solar cell cover for energy harvesting at surface, and 504 represents a vertical turbine which is retracted when the AUV is near a water surface or when the AUV is gliding through a water volume.

[0073] In an embodiment, when the AUV is at the water surface, the energy of waves is harvested by an energy motion power generator, namely an internal module installed in both VBS sections 200, 201.

[0074] Figure 6 show a schematic representation of a long-range autonomous underwater vehicle with turbines for energy harvesting wherein 504 represents a vertical turbine for energy harvesting from low-speed currents flow when bottoming - that are retractable in and out of the main body, and 507 represents retractable supporting legs for landing the AUV at the seabed and, optionally, the AUV harvests the energy of the sea currents at this position.

[0075] In an embodiment, the AUV comprises energy harvesting systems, e.g., solar cells or vertical turbines or an energy motion power generator.

[0076] The installation of a large area of solar panels on the top of the vehicle allows the charging during days at the surface. Integrating a turbine to harvest energy from water flow can be used when bottoming at the seabed and optionally when gliding but losing some gliding efficiency.

[0077] In an embodiment, the AUV has advanced Energy management that allows a fine selection of the subsystems that need to be powered to achieve ultra-low power modes. It detects any malfunctioning system and provides protection capabilities, isolating it from other working systems.

[0078] Figure 7 shows a schematic representation of the path of the long-range autonomous underwater vehicle when gliding, wherein 701 represents a water surface, 702 represents a path of the long-range AUV, 703 represents a seabed, and 704 represents a long-range AUV.

[0079] In an embodiment, the path of the long-range AUV describes a sawtooth-like profile with the top and bottom round-shaped. Depending on the vertical amplitude available, and since the VBS is a slow system, it takes several minutes to change the buoyancy from negative to positive and the same to change from positive to negative. So, it takes some time to invert the vertical direction of the AUV motion, resulting in the profile shown in Fig. 7, with a parabolic-shaped profile at the top and at the bottom limit.

[0080] In an embodiment, there is a pre-defined safe margin to the surface of the water, the AUV thus sensing the top of the water column to get complete awareness of the presence of threads at surface, and / or a safe margin to the seabed to go as near as possible to underwater sensing systems.

[0001] In an embodiment, the AUV uses one or more hydrophones couple with sound acquisition system and signal processing techniques to identify, locate and track threads at surface, before surfacing.

[0081] In an embodiment, the AUV combines advanced navigation methods (for the logistics operations in the target location) with ultra-low power navigation methods for long distances travelling with low power consumption.

[0082] In an embodiment, the advanced navigation methods combine perception (to measure the relative positioning, e.g., to systems placed in the seabed or in the water column, and the physical restriction from seabed / environment morphology) and the complete controllability of the AUV, using the lateral / vertical / propulsion thrusters, and the buoyancy adjustment capability, using the VBS. These navigation methods allow the accurate and precise relative positioning that is relevant for supporting operations (i.e., deploy / retrieve cargo, energise and maintenance operations). Simultaneously, this allows to save energy by facing the AUV against underwater / seabed currents when they are high.

[0083] In an embodiment, spatial sensors and several perception / awareness functionalities for long-term deployments and logistic operations allow a precise mapping of seabed for deployment / recovering equipment; the acoustic detection of vessels at the surface provides safety when surfacing for charging or data communications by satellite; detection of fishnets and other obstacles in the water column for safe navigation.

[0084] In an embodiment, the high bandwidth optical modems for communication allow for the efficient retrieval / collection of monitoring data from deployed monitoring systems on the seabed and / or in the water column. This is possible combined with the motion capabilities for the correct positioning of the AUV and perception and awareness capabilities for relative positioning to the seabed / underwater system.

[0085] The integrated wireless energy transfer systems can be installed at the bottom of the AUV or in a small tethered platform that can approach the systems in the seabed closely.

[0086] The present long-range AUV is a lighter vehicle, e.g., weighting 2-3 ton, due to smaller size, e.g., 7-12 m of length, and due to the VBS, compared to other long range AUV known from the state of the art.

[0087] In an embodiment, the long-range AUV has a weight ratio higher than 10% of the total weight in variability in buoyancy, thus providing an excellent capability tocope with the needs of adaptation in bouncy for both the transport and the gliding capability.

[0088] The long-range autonomous underwater vehicle of the present disclosure has the capacity to transport, deploy, and retrieve other systems to the deep-sea seabed or in the water column, covering long distances and depths. The AUV also gives support to the deployed systems through charging and data transfer, thus extending their permanence at sea. This opens the possibility for long-term monitoring operations of deep and remote locations without requiring very expensive support vessels in permanent operations.

[0089] Compared with the prior art, the present solution offers a distinctive set of characteristics and beneficial effects. It boasts enhanced transport capacity, facilitating efficient movement to and from remote locations and the deep-sea seabed. Notably, it excels in autonomously achieving precise and accurate positioning of equipment within the seabed, while also providing essential support to seabed equipment through autonomous energy and data transport capabilities.

[0090] The system's variable buoyancy and modular structure enhance its adaptability and operational versatility. Moreover, it showcases extended operation periods and remarkable long-range capability, bolstered by the capacity to auto-recharge through integrated solar panels, waves kinetic energy harvesting and water currents in the seabed.

[0091] These features unlock a multitude of potential applications, including environmental assessments, critical underwater infrastructure monitoring and protection, seabed warfare, and deep-sea mining. Notably, the system's autonomous operation eliminates the need for a surface ship for deployment and recovery on the deep seabed or in the water column, while its extensive operational range enables a wide area of coverage, spanning hundreds of kilometres. Furthermore, its precise navigation capabilities, coupled with substantial payload capacities, ensure the precise deployment and recovery of sensor nodes, further enhancing its utility and efficacy in various underwater operations and exploration endeavours.

[0092] A computer data processor, as used herein, refers to any system, device, or apparatus capable of processing data in accordance with the methods described in this disclosure. The computer data processor may include one or more processors, such as a central processing unit (CPU), a graphics processing unit (GPU), a digital signal processor (DSP), or any combination thereof. These processors may be implemented as a single chip, a multi-core processor, a distributed computing system, or any other suitable configuration. For example, this can be a central processing unit (CPU), such as an Intel® Core™ i7 processor, and memory modules, including 16 GB of DDR4 RAM. The system may include a solid-state drive (SSD) for storage, an optional GPU (e.g., NVIDIA® GeForce RTX™ 3060), and runs a standard operating system, such as Microsoft® Windows® or Linux®. For example, this can be an embedded system utilizing a microcontroller, such as the ARM® Cortex®-M4 processor, with onboard memory (e.g., 1 MB of flash storage and 256 KB of SRAM). This system operates with real-time operating system (RTOS) software and can be integrated into an industrial device. The instance can be configured for example with 32 GB of RAM, 1 TB of elastic block storage (EBS), and executes server-side software designed to perform the computational processes disclosed in this specification.

[0093] The computer data processor may further include memory (e.g., random access memory (RAM), read-only memory (ROM), flash memory, or other suitable storage devices) for storing instructions and data. The processor executes instructions stored in memory to perform the functions described in this specification. The instructions may be implemented in any programming language, including but not limited to assembly language, C, C++, Python, or Java. The computer data processor may communicate with external systems via wired or wireless connections, such as USB, Bluetooth®, Wi-Fi®, or Ethernet. The data processor may also be integrated with or connected to a network, including a local area network (LAN), wide area network (WAN), or the internet, to receive and transmit data.

[0094] The term "comprising" whenever used in this document is intended to indicate the presence of stated features, integers, steps, components, but not to preclude the presence or addition of one or more other features, integers, steps, components, or groups thereof. The disclosure should not be seen in any way restricted to theembodiments described and a person with ordinary skill in the art will foresee many possibilities to modifications thereof. The above-described embodiments are combinable. The following claims further set out particular embodiments of the disclosure.

[0095] References[1] https: / / www.smd.co.uk / our-products / work-class-rovs / [2] E. Silva et al., "TURTLE - a robotic autonomous deep-sea lander," OCEANS 2016 MTS / IEEE Monterey, Monterey, CA, USA, 2016, pp. 1-5[3] Webb, Douglas C. , P. J. Simonetti , and C. P. Jones, "SLOCUM: An underwater glider propelled by environmental energy," IEEE J. of Ocean. eng 26.4(2001):447-452.[4] Chong-Jie, Liu , et al, "Realization of low power consumption control system for underwater glider," Machinery Design & Manufacture (2011).[5] Johnston S, Rudnick D L, Sherman J T, "Rapid Near-inertial Internal Wave Group Propagation Through the Transition Layer from Float and Glider Observations in the Bay of Bengal," American Geophysical Union, Ocean Sciences Meeting (2016), Abstract #po43c.[6] Hobson B W, Bellingham J G, Kieft B, et al, "Tethys-class long range AUVs - extending the endurance of propeller-driven cruise AUVs from days to weeks", Autonomous Underwater Vehicles. I EEE,(2012) :l-8.[7] Furlong M E , Paxton D , Stevenson P , et al, "Autosub Long Range: A long range deep diving AUV for ocean monitoring", Autonomous Underwater Vehicles. IEEE(2012).[8] Mcphail S, "Autosub6000: A Deep Diving Long Range AUV", Journal of Bionics Engineering, 6(1) (2009):55-62.[9] Huang Y.,et al 2019a. "Sea-whale 2000: A long-range hybrid autonomous underwater vehicle for ocean observation" OCEANS 2019 - Marseille (2019), pp. 1-6

[0010] Huang Y., et al, 2019b. "Development and experiments of the passive buoyancy balance system for sea-whale 2000 AUV" OCEANS 2019 - Marseille (2019), pp. 1-5,

[0011] Phillips et al "Autosub Long Range 1500: A continuous 2000 km field trial. OceanEngineering 280 (2023) 114626

[0012] https: / / www.cellula.com / solus-xr

Claims

C L A I M S1. A long-range autonomous underwater vehicle (AUV) for underwater gliding by variable-buoyancy control, for transporting, deploying and retrieving underwater payload, comprising one or more gliding surfaces, one or more propulsion thrusters, one or more hovering thrusters, two or more variable buoyancy ballast tanks, and an electronic data processor configured to carry out, in any order, the steps of: adjusting the one or more gliding surfaces and one or more of the two or more variable buoyancy ballast tanks for underwater gliding; actuating the one or more propulsion thrusters, and the one or more hovering thrusters, for deploying the underwater payload; and actuating the one or more propulsion thrusters, and the one or more hovering thrusters, for retrieving the underwater payload.

2. The long-range AUV according to the previous claim wherein the variable buoyancy ballast tanks are interconnected for the passage of a fluid between the two or more variable buoyancy ballast tanks for simultaneously pitching the AUV and for varying the buoyancy of the AUV.

3. The long-range AUV according to any of the previous claims wherein the electronic data processor is further configured to deactivate the one or more propulsion thrusters and the one or more hovering thrusters when underwater gliding.

4. The long-range AUV according to any of the previous claims wherein the electronic data processor is further configured for varying the buoyancy of the two or more variable buoyancy ballast tanks when deploying or retrieving the underwater payload in order to stabilise AUV buoyancy.

5. The long-range AUV according to any of the previous claims further comprising spatial sensors and / or navigational sensors, namely passive and active acoustic detectors, visual detectors, camera, sonar, scanning sonar, multibeamechosounder, side-scan sonar, structured light sensor, IMU, DVL, pressure sensor, or a combination of any of these, in particular the long-range AUV comprising a high bandwidth optical modem and / or an acoustic modem for communication.

6. The long-range AUV according to any of the previous claims wherein the one or more gliding surfaces comprise at least a pair of fins with an optional fixed part and a controllable or adjustable part.

7. The long-range AUV according to any of the previous claims further comprising a bidirectional wireless charger for inductive coupling for charging a seabed node, preferably when hovering, in particular an underwater sensor.

8. The long-range AUV according to the previous claim wherein the bidirectional wireless charger is placed at a bottom of the long-range AUV or in a separated tethered platform extension.

9. The long-range AUV according to any of the previous claims further comprises at least one energy harvester, preferably a solar panel on a top of the vehicle, wave power generator, a thermoelectric generator (TEG), a turbine to harvest energy from a moving water flow, or a combination of these.

10. The long-range AUV according to any of the previous claims wherein the underwater payload is at least one of: a secondary AUV, a seabed node, underwater equipment, an underwater cable, or a cable array, in particular one or more smaller AUVs.

11. The long-range AUV according to any of the previous claims comprising a sound acquisition and signal processing system, and one or more hydrophones for detecting and locating obstacles at sea surface, and wherein the electronic data processor is further configured to delay surfacing until said obstacles are no longer detected.

12. A method of operating the long-range autonomous underwater vehicle (AUV) of any of the claims 1-11 for underwater gliding by variable-buoyancy control, for transporting, deploying and retrieving underwater payload, the method comprising, in any order, the steps of: adjusting one or more gliding surfaces and one or more of the two or more variable buoyancy ballast tanks for underwater gliding; actuating one or more propulsion thrusters, and one or more hovering thrusters for deploying the underwater payload; actuating one or more propulsion thrusters, and one or more hovering thrusters for retrieving the underwater payload; and actuating one or more propulsion thrusters, and one or more hovering thrusters for seabed operation, in particular for charging underwater devices or data collecting underwater devices, further in particular seabed nodes.

13. The method according to the previous claim, wherein deploying the underwater payload comprises lowering said payload via a drone extension, winching a mechanical or magnetic release or catching device, or directly placing said payload on the seabed using an articulated arm.

14. The method according to any of the previous claims 12-13 wherein retrieving the payload comprises hoisting or catching the underwater payload.

15. The method according to any of the previous claims 12-14 comprising a first step of retrieving the underwater payload from a first georeferenced site and a subsequent step of deploying the underwater payload on a second georeferenced site.

16. The method according to the previous claim wherein the first and second georeferenced sites identify an underwater location up to 6000 m of depth or a location in the water column.

17. The method according to any of the previous claims 12-16 comprising a step of receiving sensor data from spatial sensors, navigational sensors, and / or external underwater sensors.

18. The method according to any of the previous claims 12-17 comprising a step of establishing a data link via a bidirectional wireless connection with an external underwater sensor, preferably the bidirectional wireless connection is an optical, acoustic, or electromagnetic wireless connection.

19. The method according to any of the previous claims 12-18 comprising a step of establishing an inductive coupling between the long-range AUV and an underwater device for supplying electrical power to the underwater device and / or between the long-range AUV and an external power supplier for supplying electrical power to the long-range AUV.

20. The method according to any of the previous claims 12-19 further comprising a step of harvesting energy, preferably via a solar panel, a wave power generator, a thermoelectric generator (TEG), a turbine to harvest energy from a moving water flow, or a combination of these.

21. The method according to any of the previous claims 12-20 wherein the underwater payload is at least one of: a secondary AUV, a seabed node, underwater equipment, an underwater cable, or a cable array, in particular one or more smaller AUVs.

22. The method according to any of the previous claims 12-21 further comprising a step of landing at a seabed and entering an ultra-low power hibernation mode.

23. The method according to the previous claim 22 further comprising a step of harvesting energy, in particular using vertical turbines, when hibernated in the landed position in a seabed.

24. The method according to any of the previous claims 12-23 comprising a step of harvesting energy when at surface by solar energy and / or wave energy.

25. The method according to any of the previous claims 12-24, comprising a step of harvesting energy when gliding with the retractable vertical generator extended down.

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