SYSTEM AND METHOD FOR RECOVERY OF AUTONOMOUS UNDERWATER VEHICLES

Abstract

An autonomous tethered vehicle for recovering autonomous underwater vehicles (AUVs) is provided. The autonomous tethered vehicle includes an open-structure frame with vertical and horizontal frame members and a top surface attached to a top portion of the open-structure frame. The autonomous tethered vehicle further includes at least four horizontal thrusters operable to provide lateral maneuvering and at least two vertical thrusters operable to provide vertical thrust. Additionally, the autonomous tethered vehicle includes a plurality of onboard sensors operable to provide positional information of the autonomous tethered vehicle in reference to a nearby AUV, and an electronics housing unit having a control system operable to collect data from the plurality of the onboard sensors and make real-time operational decisions based on the collected data.

Claims

1. A tethered vehicle for recovering autonomous underwater vehicles, comprising: an open-structure frame comprising vertical and horizontal frame members; a top surface attached to a top portion of the open-structure frame; at least four horizontal thruster, each positioned on a respective vertical frame member of the open-structure frame, the four horizontal thrusters operable to provide lateral maneuvering to the tethered vehicle; at least two vertical thruster integrated into the top surface and operable to provide vertical thrust to the tethered vehicle; a plurality of onboard sensors attached to the open-structure frame, the plurality of onboard sensor operable to provide positional information of the tethered vehicle in reference to a nearby autonomous underwater vehicle (AUV); and an electronics housing unit attached to the open-structure frame, the electronics housing unit comprising a control system operable to collect data from the plurality of the onboard sensors and make real-time operational decisions for the tethered vehicle based on the collected data.

2. The tethered vehicle of claim 1, wherein the control system allows the tethered vehicle to seek and attach to the AUV autonomously or with limited human intervention.

3. The tethered vehicle of claim 1, wherein the open-structure frame is made from a lightweight material.

4. The tethered vehicle of claim 1, wherein the plurality of onboard sensors comprises acoustic sensors operable to receive acoustic signals emitted from the AUV.

5. The tethered vehicle of claim 1, wherein the plurality of onboard sensors comprises four cameras operable to optically identify fiducial targets on the AUV.

6. The tethered vehicle of claim 1, further comprising an actuator positioned on the top surface (208) of the tethered vehicle operable to enable vertical movement of the tethered vehicle along a length of a crane cable traversing the top surface of the tethered vehicle.

7. The tethered vehicle of claim 6, wherein the crane cable comprises a docking mechanism configured to mechanically latch on a corresponding receptacle on the AUV to mechanically couple the tethered vehicle to the AUV.

8. The tethered vehicle of claim 7, wherein the vertical position of the docking mechanism relative to the AUV is controlled with a hard stop attached to the crane cable above the actuator.

9. The tethered vehicle of claim 6, wherein the crane cable is a multi-functional conduit configured to facilitate both mechanical deployment and data connectivity between the tethered vehicle and a recovery vessel.

10. The tethered vehicle of claim 9, wherein the electronics housing unit is communicatively coupled to the crane cable so that the control system becomes communicatively coupled to the recovery vessel.

11. A method for recovering autonomous underwater vehicles, comprising: instructing an autonomous underwater vehicle (AUV) to approach a recovery vessel at a predetermine underwater location; deploying an autonomous tethered vehicle from a deck of the recovery vessel at the predetermined underwater location, the autonomous tethered vehicle being tethered to the recovery vessel via a crane cable; upon deployment of the autonomous tethered vehicle from the deck of the recovery vessel, allowing the recovery vessel to enter a drift mode to minimize its relative motion to the autonomous tethered vehicle; the autonomous tethered vehicle, using a first set of sensors attached to an open-structure frame of the autonomous tethered vehicle, detecting the AUV and navigating towards the AUV to position itself over the AUV; the autonomous tethered vehicle, using a second set of sensors attached to the open-structure frame of the autonomous tethered vehicle, detecting fiducial targets on the AUV and subsequently using the fiducial targets as alignment marks to align to the AUV; and upon alignment with the AUV, the autonomous tethered vehicle deploying a docking mechanism attached to an end of the crane cable towards a receptacle on the AUV to dock the AUV.

12. The method of claim 11, further comprises: lifting the autonomous tethered vehicle and the docked AUV from sea level to the deck of the recovery vessel; and upon lowering the autonomous tethered vehicle and the docked AUV to the deck of the recovery vessel, aligning the docked AUV to a capture frame on the deck.

13. The method of claim 11, wherein deploying the autonomous tethered vehicle from the deck of the recovery vessel comprises: attaching the autonomous tethered vehicle to a crane via the crane cable; with the crane lifting the autonomous tethered vehicle from the deck of the recovery vessel and positioning the autonomous tethered vehicle over sea water; and lowering the autonomous tethered vehicle to sea level above the predetermined underwater location.

14. The method of claim 11, wherein using the first set of sensors attached to the open-structure frame of the autonomous tethered vehicle comprises using acoustic sensors operable to receive acoustic signals emitted from the AUV.

15. The method of claim 11, wherein using the second set of sensors attached to the open-structure frame of the autonomous tethered vehicle comprises using optical sensors.

16. The method of claim 15, wherein the optical sensors comprise digital cameras.

17. The method of claim 11, wherein deploying the docking mechanism comprises using an actuator attached to a top surface of the autonomous tethered vehicle above the open-structure frame, the actuator operable to enable vertical movement of the autonomous tethered vehicle along a length of the crane cable.

18. The method of claim 17, wherein a vertical position of the docking mechanism relative the AUV is controlled with a hard stop attached to the crane cable above the actuator.

19. The method of claim 1, wherein the autonomous tethered vehicle while navigating towards the AUV and deploying the docking mechanism uses horizontal and vertical thrusters controlled by an onboard control system to maintain alignment with the AUV under high-current underwater conditions.

20. The tethered vehicle of claim 1, wherein the crane cable is a multi-functional conduit configured to facilitate mechanical deployment and data connectivity between the autonomous tethered vehicle and the recovery vessel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying figures, which are included as part of the present specification, illustrate the presently preferred embodiments and together with the general description given above and the detailed description of the preferred embodiments given below serve to explain and teach the principles described herein.

[0013] FIG. 1 shows a recovery vessel equipped with a crane for the deployment of an autonomous tethered vehicle, in accordance with some embodiments.

[0014] FIG. 2 shows a detailed view of an autonomous tethered vehicle, in accordance with some embodiments.

[0015] FIG. 3 shows an autonomous tethered vehicle and an autonomous underwater vehicle, in accordance with some embodiments.

[0016] FIG. 4 shows a recovery vessel equipped with a crane for the deployment of an autonomous tethered vehicle and a capture frame for positioning an autonomous underwater vehicle, in accordance with some embodiments.

[0017] FIG. 5 shows an autonomous underwater vehicle captured by an autonomous tethered vehicle hanging over the deck of a recovery vessel, in accordance with some embodiments.

[0018] While the present disclosure is subject to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and will herein be described in detail. The present disclosure should not be understood to be limited to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure.

DETAILED DESCRIPTION

[0019] According to some embodiments, FIG. 1 illustrates an exemplary recovery vessel 102 equipped with a crane 104 configured to deploy an autonomous tethered vehicle 106 from the deck of the recovery vessel 102 to the sea surface, and subsequently retrieve the vehicle back to the deck. The autonomous tethered vehicle 106 is designed to approach, engage with, and capture autonomous underwater vehicles (AUVs), thereby facilitating their recovery by the vessel 102. As used herein, the term autonomous refers to the tethered vehicle's capability to independently navigate, track, and interact with AUVs below the sea level using onboard sensors, control systems, and decision-making algorithms, without requiring continuous human oversight. Although physically connected via a tether (e.g., for power and/or communication), the vehicle maintains operational autonomy through its ability to perceive its surroundings, adapt to dynamic underwater conditions, and execute complex capture maneuvers with minimal operator intervention. It should be understood that while the tethered vehicle 106 is described as autonomous, non-autonomous variants are also within the scope of this disclosure. For example, the tethered vehicle 106 may alternatively be a robotic system manually operated in part or exclusively by a human operator aboard the recovery vessel 102.

[0020] By way of example and not limitation, crane 104 may be an A-frame crane equipped with a slew and snubbing mechanism (not shown in FIG. 1). In some embodiments, crane 104 may be one of multiple cranes forming part of a launch and recovery (LAR) system configured to deploy and retrieve both autonomous tethered vehicles 106 and AUVs, as described herein. Crane 104 may be pivotally mounted to the deck of the recovery vessel 102, allowing it to rotate forward and backward about pivot points located at its base. The pivoting motion may be actuated by hydraulic pistons 108 in combination with the slew and snubbing mechanism. Although crane 104 is described as an A-frame crane, it is understood that other crane types may be employed, including but not limited to knuckle boom cranes, offshore cranes, or other suitable alternatives, or any combination thereof. A winch 112 and a crane cable 110 is also be provided to assist with lifting and deployment operations discussed in further detail below.

[0021] According to some embodiments, FIG. 2 illustrates an isometric schematic view of the autonomous tethered vehicle 106. In certain implementations, the autonomous tethered vehicle 106 may be permanently affixed to the end of crane cable 110. However, in other embodiments, the vehicle may be removably attached via a suitable securing mechanism, allowing for greater operational flexibility. In some configurations, the autonomous tethered vehicle 106 is further configured to translate along the length of crane cable 110 or to lock into position at a desired location using an actuator 202. The vehicle's upward vertical travel may be constrained by a hard stop 204, which serves as a mechanical limit.

[0022] The position of hard stop 204 along crane cable 110 may be adjustable, depending on the required extension of the cable below the bottom portion of the vehicle's frame 206. Accordingly, hard stop 204 may be clamped at any convenient height relative to a top surface 208 of the autonomous tethered vehicle 106. This adjustability provides enhanced compatibility with vehicles of varying sizes and configurations.

[0023] In some embodiments, crane cable 110 also serves as a conduit for power and data transmission to the autonomous tethered vehicle 106. Preferably, crane cable 110 is a flexible, neutrally buoyant cable constructed with high-strength members to ensure mechanical durability while maintaining a minimal cross-sectional profile to reduce hydrodynamic drag during underwater operations.

[0024] In preferred embodiments, the frame 206 of the autonomous tethered vehicle 106 is constructed as a lightweight, open-structure frame, comprising a minimal number of solid panel surfaces to reduce hydrodynamic drag during underwater operations. The frame may consist of structural members with streamlined cross-sections, optimized for low resistance and high maneuverability in dynamic marine environments. These members may be fabricated from strong yet lightweight materials, such as carbon fiber composites, marine-grade aluminum alloys, titanium, or stainless steel, selected based on mission-specific requirements including corrosion resistance, strength-to-weight ratio, and cost.

[0025] The shape and dimensions of the autonomous tethered vehicle 106 may be tailored to match the geometry of the AUV being recovered, particularly the surface area and contours where docking and attachment occur. In some implementations, the frame 206 may be modular or reconfigurable to accommodate AUVs of varying sizes and profiles, enhancing the system's versatility across different platforms.

[0026] Internally, the frame 206 may be sized to house control units, power distribution systems, navigation electronics, acoustic and optical sensors, and multiple thrusters required for precise six-degree-of-freedom maneuvering. In certain configurations, the tethered vehicle may also support interchangeable payload bays or sensor modules, enabling adaptation to different recovery scenarios or environmental conditions. The design may further incorporate buoyancy control elements or trim adjustment features to maintain neutral buoyancy and optimal stability during docking operations.

[0027] In some embodiments, the frame 206 of the autonomous tethered vehicle 106 may be implemented as a modular structure, comprising a set of interchangeable frame segments, mounting brackets, and interface panels that can be assembled or reconfigured based on mission-specific requirements. This modularity enables the tethered vehicle to accommodate AUVs of varying sizes, shapes, and docking interfaces by adjusting the spacing, orientation, or number of structural members.

[0028] For example, the frame may include removable crossbeams or adjustable-length struts that allow the overall footprint of the vehicle to be expanded or contracted. Mounting points for thrusters, sensors, and docking mechanisms may be standardized or rail-mounted, enabling repositioning or replacement without structural modification. In some configurations, payload bays or sensor pods may be hot-swappable, allowing the vehicle to be quickly re-tasked for different recovery scenarios or environmental conditions.

[0029] The modular design also facilitates maintenance, transport, and scalability. Damaged components can be replaced individually, and the frame can be disassembled for compact storage or shipping. Additionally, modularity supports future upgrades, such as integrating new sensor technologies or propulsion systems, without requiring a complete redesign of the vehicle.

[0030] According to some embodiments, when submerged, the autonomous tethered vehicle 106 is optimized for high-speed horizontal travel and precise lateral maneuvering through the use of a four-thruster configuration. Specifically, the vehicle is equipped with four horizontal thrusters 210, each configured to pivot independently about a vertical axis z at an angle , where is less than or equal to 90 (90). This configuration enables the vehicle to rapidly change its lateral direction of travel with minimal hydrodynamic resistance. In some implementations, each horizontal thruster 210 may be individually controlled in both speed and direction, enabling fine-tuned navigation and dynamic response to underwater conditions.

[0031] It is to be understood that the positioning of the horizontal thrusters 210 on the frame members of the autonomous tethered vehicle 106 is not limited to the configuration depicted in FIG. 2. Rather, the placement, orientation, and number of thrusters may vary depending on the size, mass distribution, and maneuverability requirements of the autonomous tethered vehicle. In some implementations, the thrusters may be mounted at different heights or angles along the frame 206 to optimize thrust vectoring, improve hydrodynamic efficiency, or accommodate specific mission profiles. Additionally, the thruster configuration may be adapted to support modular frame designs, allowing for reconfiguration based on the geometry of the AUV being recovered or the operational environment.

[0032] To facilitate vertical movement, a pair of vertical thrusters 212 may be integrated into the top surface 208 of the vehicle, allowing for controlled ascent and descent. It is to be understood that the placement of the vertical thrusters 212 on the autonomous tethered vehicle 106 is not limited to the configuration depicted in FIG. 2. While in some embodiments the vertical thrusters may be integrated into the top surface 208 of the frame 206, their position, orientation, and number may vary depending on the vehicle's size, center of mass, and desired vertical control authority. For example, vertical thrusters 212 may be mounted on side arms, internal compartments, or modular pods to optimize thrust distribution and minimize hydrodynamic interference. In certain implementations, multiple smaller thrusters may be distributed across the frame to provide redundancy and fine-grained control, while in others, larger centralized units may be used to maximize lift capacity. This flexibility in thruster placement supports a wide range of operational profiles and enables the tethered vehicle to maintain stable and responsive vertical maneuverability under varying load conditions and environmental forces.

[0033] The control system responsible for operating the horizontal and vertical thrusters may be housed, without limitation, in an electronics housing unit 214 mounted to a suitable location on the vehicle's frame 206. This control system may also include navigation systems and processing electronics configured to collect data from onboard sensors and make real-time operational decisions based on that data. In further embodiments, the electronics housing unit 214 is communicatively coupled to crane cable 110 via one or more wired connections, enabling power delivery and data exchange with systems aboard the recovery vessel 102. The electronics housing unit 214 may be mounted to a central or protected portion of the frame 206. In some embodiments, this housing unit is designed to be watertight, pressure-resistant, and thermally managed, ensuring reliable operation in harsh underwater environments.

[0034] In some implementations, the electronics housing unit 214 may be modular, allowing for easy access, maintenance, or upgrades. In some implementations, redundant control units may be included to provide fault tolerance, ensuring continued operation in the event of a subsystem failure. Placement of the electronics housing unit 214 is optimized to minimize impact on the vehicle's center of mass and buoyancy, protect sensitive electronics from collision or entanglement hazards, and maintain thermal balance through passive or active cooling strategies.

[0035] By way of example and not limitation, the control system housed in the electronics housing unit 214 may include embedded processors or microcontrollers for real-time control and decision-making, power management modules for distributing energy from the tether or onboard sources, communication interfaces for data exchange with the recovery vessel 102 via the crane cable 110, sensor fusion processors for integrating data from inertial measurement units (IMUs), Doppler velocity logs (DVLs), acoustic sensors, and optical systems, and motor controllers for managing thruster output and actuator functions.

[0036] In some embodiments, the autonomous tethered vehicle 106 may be equipped with a docking mechanism 216 positioned at the end of crane cable 110, below the frame 206. The docking mechanism 216 may include a secondary alignment capture mechanism configured to facilitate precise alignment between the autonomous tethered vehicle 106 and an AUV. Such alignment may enable the transfer of payloads through designated interface points on the AUV. In certain implementations, the secondary alignment capture mechanism may be configured to drive the autonomous tethered vehicle 106 downward onto the AUV and/or to draw the AUV upward toward the vehicle using an actuator (not shown). This dual-mode engagement capability enhances the reliability and versatility of the docking process, particularly in dynamic underwater environments.

[0037] As part of the secondary alignment capture mechanism, the autonomous tethered vehicle 106 may be equipped with one or more downward-facing sensors 218, such as digital cameras, to assist in the alignment process between the vehicle and the AUV. These sensors may be supplemented by downward-facing illumination sources (not shown in FIG. 2) to enhance visibility in low-light underwater environments. For example, the sensors 218 may include a plurality of digital cameras, such as four cameras, strategically positioned to provide comprehensive visual coverage during docking operations. Accordingly, the autonomous tethered vehicle 106 may utilize computer vision to analyze and process the images obtained by the digital cameras.

[0038] Alternatively or additionally, the autonomous tethered vehicle 106 may be equipped with one or more acoustic sensors to assist in locating and aligning with the AUV during recovery operations. These sensors may include hydrophones for passive detection of acoustic signals emitted by the AUV, as well as acoustic transducers or projectors for active sonar-based ranging and positioning. In certain implementations, the vehicle may also incorporate a short baseline (SBL) or ultra-short baseline (USBL) acoustic positioning system, enabling precise triangulation of the AUV's location relative to the tethered vehicle. These acoustic systems may operate in conjunction with onboard navigation and control algorithms to facilitate real-time tracking, alignment, and docking, even in low-visibility or high-current underwater environments.

[0039] In some embodiments, the autonomous tethered vehicle 106 may be equipped with an inertial positioning system to enhance underwater navigation and alignment capabilities, particularly in environments where acoustic and optical signals are intermittent or unreliable. Such systems may include an IMU comprising accelerometers, gyroscopes, and magnetometers to measure linear acceleration, angular velocity, and orientation. These measurements may be processed through sensor fusion algorithms, such as Kalman filtering, to estimate the vehicle's position and trajectory over time. When integrated with acoustic positioning systems, the inertial positioning system can provide continuous, high-resolution navigation data, enabling the autonomous tethered vehicle 106 to maintain accurate alignment with an AUV during docking and recovery operations.

[0040] Additionally, the vertical position of the docking mechanism 216 may be controlled using the hard stop 204 on crane cable 110. The autonomous tethered vehicle 106 may also utilize actuator 202 to move vertically along the length of crane cable 110, with its range of motion constrained by the position of hard stop 204. This configuration enables precise control over the docking depth and alignment, enhancing the reliability of AUV capture and payload transfer operations.

[0041] According to some embodiments, during a recovery operation, an overall command software system may coordinate the actions of both the autonomous tethered vehicle 106 and the AUV, determining an optimal meeting location and time for rendezvous. For example, the free-swimming AUV may be instructed to navigate to a designated location and depth below the wave-affected zone, where it may loiter in a stationary position in preparation for recovery by the recovery vessel 102.

[0042] The recovery vessel 102 may then transit to a prescribed location and deploy the autonomous tethered vehicle 106 into the water. Upon deployment, the vessel may enter a drift mode to minimize relative motion between the ship and the autonomous tethered vehicle 106 during the docking sequence. In some embodiments, both the autonomous tethered vehicle 106 and the AUV may be configured to track and follow the recovery vessel 102, maintaining proximity and alignment throughout the recovery process.

[0043] In some embodiments, the autonomous tethered vehicle 106 may utilize its integrated acoustic, inertial, and optical positioning systems to navigate toward and rendezvous with a free-swimming AUV. Once the tethered vehicle reaches close proximity to the AUVtypically within a range of approximately 2 to 5 meters, depending on water claritythe onboard control system of the recovery vessel 102, which oversees and coordinates the recovery operation, may transition to a purely relative optical navigation mode. In this mode, the system leverages data from the downward-facing sensors 218 on the autonomous tethered vehicle 106 to perform fine alignment and docking maneuvers with the AUV, ensuring precise and reliable capture under varying underwater conditions.

[0044] FIG. 3 illustrates the autonomous tethered vehicle 106 approaching and aligning with a free-swimming AUV 302. During this phase, the downward-facing sensors 218 on the tethered vehicle actively search for and track one or more fiducial targets 304 located on the upper surface of the AUV 302. These fiducial targets may include high-contrast visual markers, such as geometric patterns (e.g., checkerboards, concentric circles, or ArUco codes), or retroreflective surfaces designed to enhance visibility under artificial illumination. In some embodiments, the fiducial targets 304 may be optimized for underwater optical recognition, incorporating materials or coatings that maintain contrast and reflectivity in low-light or turbid conditions.

[0045] The fiducial targets 304 serve as reference points for the docking mechanism 216 on the tethered vehicle to align precisely with a corresponding receptacle 306 on the AUV. In certain configurations, the docking interface may employ either a passive engagement mechanism, such as tapered guides, magnetic couplings, or mechanical latches that secure upon contact, or an active engagement mechanism, which may include motorized clamps, actuators, or locking pins that are triggered upon successful alignment. These mechanisms ensure a secure and reliable connection between the two vehicles.

[0046] Once docking is achieved, the winch 112 on the recovery vessel 102 is activated to retract the crane cable 110, drawing both the autonomous tethered vehicle 106 and the AUV 302 upward toward the crane 104. The combined assembly is then lifted from the water and returned to the deck of the recovery vessel 102.

[0047] Referring now to FIG. 4, once the autonomous tethered vehicle 106 and the AUV 302 are lifted from the water, a capture frame 402 located on the deck of the recovery vessel 102 is used to guide the AUV 302 into a precise docking position. The capture frame 402 may include funnel-like structural features that assist in passively aligning the AUV as it is lowered, after which one or more active latching mechanisms (not shown in FIG. 4) secure the AUV in place for handling, servicing, or payload retrieval. This step ensures safe and repeatable capture of the AUV, even in dynamic sea states.

[0048] As shown in FIG. 5, the AUV 302 remains attached to the autonomous tethered vehicle 106 while suspended above the deck, just prior to final positioning within the capture frame 402. In some implementations, the top surface of the AUV 302 may be flush with the bottom surface of the autonomous tethered vehicle 106, and the entire assembly may be aligned beneath a snubbing mechanism to stabilize the system during final recovery operations.

[0049] According to some embodiments, following servicing and/or payload offloading, the crane 104 may be repositioned to lower the autonomous tethered vehicle 106 and the AUV 302 back into the water. At this stage, the AUV 302 may be released from the docking mechanism 216 to resume its mission. The autonomous tethered vehicle 106 may then either be recovered to the deck for redeployment or immediately redirected to intercept and recover another free-swimming AUV 302, enabling continuous and efficient multi-vehicle operations.

Six Degrees of Freedom (6-DOF) Maneuvering Integration

[0050] In some embodiments, the autonomous tethered vehicle 106 is configured for full six degrees of freedom (6-DOF) maneuverability, enabling precise control over its position and orientation in three-dimensional underwater space. The six degrees of freedom include translation along the X, Y, and Z axes (commonly referred to as surge, sway, and heave, respectively) and rotation about those axes (roll, pitch, and yaw). This capability is critical for executing complex docking maneuvers, maintaining alignment with an autonomous underwater vehicle (AUV) under dynamic conditions, and compensating for environmental disturbances such as currents or turbulence.

[0051] To achieve 6-DOF control, the vehicle may be equipped with a distributed thruster array, including horizontal thrusters 210 and vertical thrusters 212, strategically positioned to generate force and torque in all necessary directions. The thruster configuration may be dynamically optimized based on the vehicle's geometry, mass distribution, and mission profile.

[0052] The control system may employ multi-axis control algorithms, such as model predictive control (MPC), nonlinear proportional-integral-derivative (PID) controllers, or adaptive control schemes, to coordinate thruster outputs in real time. These algorithms process input from a suite of onboard sensorssuch as sensors 218, including IMUs, depth sensors, DVLs, acoustic positioning systems, and optical tracking systemsto estimate the vehicle's current state and compute the optimal control actions required to achieve the desired trajectory or pose.

[0053] In docking scenarios, the 6-DOF control system enables the tethered vehicle to precisely align with the AUV's docking interface, compensating for any misalignment in pitch, roll, or yaw, and maintaining stable relative positioning during engagement. This level of control is particularly advantageous when operating in low-visibility or high-current environments, where passive alignment strategies may be insufficient.

[0054] The integration of 6-DOF maneuvering with vertical control algorithms and sensor fusion systems (i.e., technologies or algorithms that combine data from multiple sensors to produce more accurate, reliable, or comprehensive information than could be obtained from any single sensor alone) ensures that the autonomous tethered vehicle can perform high-precision, autonomous recovery operations without reliance on external stabilization systems such as DP on the recovery vessel.

Additional Functionality Via the Crane Cable

[0055] In some embodiments, the crane cable 110 is configured as a multi-functional conduit that facilitates both mechanical deployment and electrical and/or data connectivity between the autonomous tethered vehicle 106 and the recovery vessel 102. This integrated configuration enables a range of enhanced operational capabilities, as described below.

[0056] Power Delivery: In certain embodiments, the crane cable 110 is operable to transmit electrical power from the recovery vessel 102 to the tethered vehicle 106. This configuration obviates the need for onboard energy storage systems, such as batteries, thereby enabling extended mission durations. In some implementations, electrical power is transmitted at high voltage and subsequently converted onboard the tethered vehicle to voltage levels suitable for powering thrusters, sensors, and control systems.

[0057] Data Communication: The crane cable 110 may include one or more fiber optic or copper conductors configured to support high-bandwidth, low-latency data communication. This enables real-time transmission of sensor data, including but not limited to video, sonar, and telemetry, from the autonomous tethered vehicle 106 to operators aboard the recovery vessel 102. Additionally, such communication pathways may support remote control or supervisory override of autonomous functions.

[0058] Command and Control: In some embodiments, the crane cable 110 facilitates the transmission of command and control signals from the recovery vessel 102 to the tethered vehicle 106. These signals may include mission updates, navigation commands, and docking instructions. This functionality is particularly advantageous in semi-autonomous operational modes, wherein human oversight is retained for critical mission phases such as docking or payload manipulation.

[0059] Health Monitoring and Diagnostics: The crane cable 110 may also be configured to relay system health and diagnostic data from the tethered vehicle 106 to the recovery vessel 102. Such data may include, for example, thruster performance metrics, internal temperature readings, and fault condition indicators. This capability supports predictive maintenance strategies and facilitates real-time troubleshooting.

[0060] Sensor Synchronization: In certain embodiments, the crane cable 110 enables synchronization of time-sensitive data generated by onboard sensorssuch as cameras, IMUs, and acoustic arrayswith systems located on the recovery vessel 102. This synchronization enhances the accuracy of navigation, localization, and alignment algorithms employed during mission execution.

Benefits Over Conventional AUV Recovery Approaches

[0061] The systems and methods described herein offer several significant advantages over conventional AUV recovery approaches. Most notably, by eliminating the requirement for DP, the disclosed system enables the use of standard transport or support vesselswhich are typically not equipped with DP capabilitiesas effective recovery platforms. This flexibility allows a single vessel to serve dual roles, both transporting AUV payloads and performing recovery operations, with minimal hardware customization. As a result, the approach offers a substantial reduction in capital and operational costs, avoiding the need for specialized DP-equipped recovery vessels and their associated fuel consumption, maintenance, and crew requirements.

[0062] Additionally, the use of an autonomous tethered vehicle to perform all alignment and docking maneuvers-both vertical and lateral-shifts the burden of precision navigation away from the AUV. This is particularly advantageous in scenarios where the AUV is operating with limited battery reserves or degraded maneuverability. By offloading the alignment task to the tethered vehicle, the AUV can conserve energy for mission-critical functions or extend its operational range. This capability enhances mission resilience and enables recovery even under constrained power conditions.

[0063] Furthermore, the system's ability to operate below the wave-affected zone improves stability and reliability during docking, reducing the impact of surface disturbances. The modular nature of the tethered vehicle also supports rapid redeployment, enabling sequential recovery of multiple AUVs without requiring the recovery vessel to return to port or reposition extensively.

SOME EMBODIMENTS

[0064] Some embodiments may include any of the following:

[0065] A1. A tethered vehicle for recovering autonomous underwater vehicles that includes an open-structure frame with vertical and horizontal frame members and a top surface attached to a top portion of the open-structure frame. The tethered vehicle further includes at least four horizontal thruster, each positioned on a respective vertical frame member of the open-structure frame, with the four horizontal thrusters operable to provide lateral maneuvering to the tethered vehicle. Additionally, the tethered vehicle includes at least two vertical thruster integrated into the top surface and operable to provide vertical thrust to the tethered vehicle. The tethered vehicle also includes a plurality of onboard sensors attached to the open-structure frame and operable to provide positional information of the tethered vehicle in reference to a nearby autonomous underwater vehicle. Further, the tethered vehicle includes an electronics housing unit attached to the open-structure frame. The electronics housing unit includes a control system operable to collect data from the plurality of the onboard sensors and make real-time operational decisions for the tethered vehicle based on the collected data.

[0066] A2. The tethered vehicle of clause A1 can include any of the following components or features, in any combination. The control system allows the tethered vehicle to seek and attach to the AUV autonomously or with limited human intervention. The open-structure frame is made from a lightweight material. The plurality of onboard sensors comprises acoustic sensors operable to receive acoustic signals emitted from the AUV. The plurality of onboard sensors comprises four cameras operable to optically identify fiducial targets on the AUV. An actuator positioned on the top surface of the tethered vehicle operable to enable vertical movement of the tethered vehicle along a length of a crane cable traversing the top surface of the tethered vehicle. The crane cable comprises a docking mechanism configured to mechanically latch on a corresponding receptacle on the AUV to mechanically couple the tethered vehicle to the AUV. The vertical position of the docking mechanism relative to the AUV is controlled with a hard stop attached to the crane cable above the actuator. The crane cable is a multi-functional conduit configured to facilitate both mechanical deployment and data connectivity between the tethered vehicle and a recovery vessel. The electronics housing unit is communicatively coupled to the crane cable so that the control system becomes communicatively coupled to the recovery vessel.

[0067] A3. A method for recovering autonomous underwater vehicles. The method includes instructing an AUV to approach a recovery vessel at a predetermine underwater location, deploying an autonomous tethered vehicle from a deck of the recovery vessel at the predetermined underwater location, where the autonomous tethered vehicle is tethered to the recovery vessel via a crane cable. Upon deployment of the autonomous tethered vehicle from the deck of the recovery vessel, allowing the recovery vessel to enter a drift mode to minimize its relative motion to the autonomous tethered vehicle. The autonomous tethered vehicle, using a first set of sensors attached to an open-structure frame of the autonomous tethered vehicle, detecting the AUV and navigating towards the AUV to position itself over the AUV. The autonomous tethered vehicle, using a second set of sensors attached to the open-structure frame of the autonomous tethered vehicle, detecting fiducial targets on the AUV and subsequently using the fiducial targets as alignment marks to align to the AUV. Upon alignment with the AUV, the autonomous tethered vehicle is deploying a docking mechanism attached to an end of the crane cable towards a receptacle on the AUV to dock the AUV.

[0068] A4. The method of clause A3 can include any of the following components or features, in any combination. The method may also include lifting the autonomous tethered vehicle and the docked AUV from sea level to the deck of the recovery vessel, and upon lowering the autonomous tethered vehicle and the docked AUV to the deck of the recovery vessel, aligning the docked AUV to a capture frame on the deck. Deploying the autonomous tethered vehicle from the deck of the recovery vessel includes attaching the autonomous tethered vehicle to a crane via the crane cable; with the crane, lifting the autonomous tethered vehicle from the deck of the recovery vessel; positioning the autonomous tethered vehicle over sea water; and lowering the autonomous tethered vehicle to sea level above the predetermined underwater location. Using the first set of sensors attached to the open-structure frame of the autonomous tethered vehicle includes using acoustic sensors operable to receive acoustic signals emitted from the AUV. Using the second set of sensors attached to the open-structure frame of the autonomous tethered vehicle includes using optical sensors. Deploying the docking mechanism includes using an actuator attached to a top surface of the autonomous tethered vehicle above the open-structure frame, the actuator operable to enable vertical movement of the autonomous tethered vehicle along a length of the crane cable. A vertical position of the docking mechanism relative the AUV is controlled with a hard stop attached to the crane cable above the actuator. The autonomous tethered vehicle while navigating towards the AUV and deploying the docking mechanism uses horizontal thrusters and vertical thrusters controlled by an onboard control system to maintain alignment with the AUV under high-current underwater conditions. The crane cable is a multi-functional conduit configured to facilitate mechanical deployment and data connectivity between the autonomous tethered vehicle and the recovery vessel.

Other Considerations

[0069] The phrasing and terminology used herein is for the purpose of description and should not be regarded as limiting.

[0070] Measurements, sizes, amounts, and the like may be presented herein in a range format. The description in range format is provided merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as 1-20 meters should be considered to have specifically disclosed subranges such as 1 meter, 2 meters, 1-2 meters, less than 2 meters, 10-11 meters, 10-12 meters, 10-13 meters, 10-14 meters, 11-12 meters, 11-13 meters, etc.

[0071] Although the concepts and principles of operation for the autonomous tethered vehicle 106 have been described with limited number of components for simplicity, the autonomous tethered vehicle 106 may include additional electrical and/or mechanical components necessary for its operation. Such components may include, but are not limited to, mechanical controllers, different types of valves and/or connectors, computers, additional electronic controllers, transformers, gears, power supplies, additional electrical control panels, etc. These additional components are within the spirit and the scope of this disclosure.

[0072] Furthermore, connections between components or systems within the figures are not intended to be limited to direct connections. Rather, data or signals between these components may be modified, re-formatted, or otherwise changed by intermediary components. Also, additional or fewer connections may be used. The terms coupled, connected, or communicatively coupled shall be understood to include direct connections, indirect connections through one or more intermediary devices, wireless connections, and so forth.

[0073] In various embodiments, the systems and/or components of the autonomous tethered vehicle 106, as described herein, are modular in nature. This modularity permits the selective addition, removal, or substitution of one or more systems, subcomponents, or functional modules, thereby enhancing the operational flexibility and adaptability of the overall system. For example, the autonomous tethered vehicle 106 may be equipped with one or more controllers, sensors, or thrusters, which may be identical to or different from those specifically described herein.

[0074] Moreover, various permutations, combinations, and modifications of these components may be implemented to achieve simplified, optimized, or otherwise more efficient configurations of the autonomous tethered vehicle 106. Such variations remain within the spirit and scope of the present disclosure and may be tailored to meet specific mission requirements, environmental conditions, or performance objectives.

[0075] Reference in the specification to one embodiment, preferred embodiment, an embodiment, some embodiments, or embodiments means that a particular feature, structure, characteristic, or function described in connection with the embodiment is included in at least one embodiment of the invention and may be in more than one embodiment. Also, the appearance of the above-noted phrases in various places in the specification is not necessarily referring to the same embodiment or embodiments.

[0076] The use of certain terms in various places in the specification is for illustration purposes only and should not be construed as limiting. A service, function, or resource is not limited to a single service, function, or resource; usage of these terms may refer to a grouping of related services, functions, or resources, which may be distributed or aggregated.

[0077] Furthermore, one skilled in the art shall recognize that: (1) certain steps may optionally be performed; (2) steps may not be limited to the specific order set forth herein; (3) certain steps may be performed in different orders; and (4) certain steps may be performed simultaneously or concurrently.

[0078] The term approximately, the phrase approximately equal to, and other similar phrases, as used in the specification and the claims (e.g., X has a value of approximately Y or X is approximately equal to Y), should be understood to mean that one value (X) is within a predetermined range of another value (Y). The predetermined range may be plus or minus 20%, 10%, 5%, 3%, 1%, 0.1%, or less than 0.1%, unless otherwise indicated.

[0079] The indefinite articles a and an, as used in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean at least one. The phrase and/or, as used in the specification and in the claims, should be understood to mean either or both of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with and/or should be construed in the same fashion, i.e., one or more of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the and/or clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to A and/or B, when used in conjunction with open-ended language such as comprising can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements).

[0080] As used in the specification and in the claims, or should be understood to have the same meaning as and/or as defined above. For example, when separating items in a list, or or and/or shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as only one of or exactly one of, or, when used in the claims, consisting of, will refer to the inclusion of exactly one element of a number or list of elements. In general, the term or as used shall only be interpreted as indicating exclusive alternatives (i.e. one or the other but not both) when preceded by terms of exclusivity, such as either, one of, only one of, or exactly one of Consisting essentially of, when used in the claims, shall have its ordinary meaning as used in the field of patent law.

[0081] As used in the specification and in the claims, the phrase at least one, in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase at least one refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, at least one of A and B (or, equivalently, at least one of A or B, or, equivalently at least one of A and/or B) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements).

[0082] The use of including, comprising, having, containing, involving, and variations thereof, is meant to encompass the items listed thereafter and additional items.

[0083] Use of ordinal terms such as first, second, third, etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed. Ordinal terms are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term), to distinguish the claim elements.

[0084] Implementations of the subject matter and the operations described in this specification can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them. Implementations of the subject matter described in this specification can be implemented as one or more computer programs, i.e., one or more modules of computer program instructions, encoded on computer storage medium for execution by, or to control the operation of, data processing apparatus. Alternatively or in addition, the program instructions can be encoded on an artificially generated propagated signal, e.g., a machine-generated electrical, optical, or electromagnetic signal, that is generated to encode information for transmission to suitable receiver apparatus for execution by a data processing apparatus. A computer storage medium can be, or be included in, a computer-readable storage device, a computer-readable storage substrate, a random or serial access memory array or device, or a combination of one or more of them. Moreover, while a computer storage medium is not a propagated signal, a computer storage medium can be a source or destination of computer program instructions encoded in an artificially-generated propagated signal. The computer storage medium can also be, or be included in, one or more separate physical components or media (e.g., multiple CDs, disks, or other suitable storage devices).

[0085] The operations described in this specification can be implemented as operations performed by a data processing apparatus on data stored on one or more computer-readable storage devices or received from other sources.

[0086] The term data processing apparatus encompasses all kinds of apparatus, devices, and machines for processing data, including by way of example a programmable processor, a computer, a system on a chip, or multiple ones, or combinations, of the foregoing. The apparatus can include special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit). The apparatus can also include, in addition to hardware, code that creates an execution environment for the computer program in question, e.g., code that constitutes processor firmware, a protocol stack, a database management system, an operating system, a cross-platform runtime environment, a virtual machine, or a combination of one or more of them. The apparatus and execution environment can realize various different computing model infrastructures, such as web services, distributed computing and grid computing infrastructures.

[0087] A computer program (also known as a program, software, software application, script, or code) can be written in any form of programming language, including compiled or interpreted languages, declarative or procedural languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, object, or other unit suitable for use in a computing environment. A computer program may, but need not, correspond to a file in a file system. A program can be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more modules, sub-programs, or portions of code). A computer program can be deployed to be executed on one computer or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communication network.

[0088] The processes and logic flows described in this specification can be performed by one or more programmable processors executing one or more computer programs to perform actions by operating on input data and generating output. The processes and logic flows can also be performed by, and apparatus can also be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit).

[0089] Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. The essential elements of a computer are a processor for performing actions in accordance with instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic disks, magneto-optical disks, optical disks, or solid state drives. However, a computer need not have such devices. Devices suitable for storing computer program instructions and data include all forms of non-volatile memory, media and memory devices, including, by way of example, semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry.

[0090] To provide for interaction with a user, implementations of the subject matter described in this specification can be implemented on a computer having a display device, e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor, for displaying information to the user and a keyboard and a pointing device, e.g., a mouse, a trackball, a touchpad, or a stylus, by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, speech, or tactile input. In addition, a computer can interact with a user by sending documents to and receiving documents from a device that is used by the user; for example, by sending web pages to a web browser on a user's client device in response to requests received from the web browser.

[0091] Implementations of the subject matter described in this specification can be implemented in a computing system that includes a back-end component, e.g., as a data server, or that includes a middleware component, e.g., an application server, or that includes a front-end component, e.g., a client computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the subject matter described in this specification, or any combination of one or more such back-end, middleware, or front-end components. The components of the system can be interconnected by any form or medium of digital data communication, e.g., a communication network. Examples of communication networks include a local area network (LAN) and a wide area network (WAN), an inter-network (e.g., the Internet), and peer-to-peer networks (e.g., ad hoc peer-to-peer networks).

[0092] The computing system can include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other. In some implementations, a server transmits data (e.g., an HTML page) to a client device (e.g., for purposes of displaying data to and receiving user input from a user interacting with the client device). Data generated at the client device (e.g., a result of the user interaction) can be received from the client device at the server.

[0093] In some embodiments, aspects of the systems and methods described herein may be implemented using ML and/or A1 technologies.

[0094] Machine learning generally refers to the application of certain techniques (e.g., pattern recognition and/or statistical inference techniques) by computer systems to perform specific tasks. Machine learning techniques may be used to build models based on sample data (e.g., training data) and to validate the models using validation data (e.g., testing data). The sample and validation data may be organized as sets of records (e.g., observations or data samples), with each record indicating values of specified data fields (e.g., independent variables, inputs, features, or predictors) and corresponding values of other data fields (e.g., dependent variables, outputs, or targets). Machine learning techniques may be used to train models to infer the values of the outputs based on the values of the inputs. When presented with other data (e.g., inference data) similar to or related to the sample data, such models may accurately infer the unknown values of the targets of the inference data set.

[0095] As used herein, model may refer to any suitable model artifact generated by the process of using a machine learning algorithm to fit a model to a specific training data set. The terms model, data analytics model, machine learning model and machine learned model are used interchangeably herein.

[0096] As used herein, the development of a machine learning model may refer to construction of the machine learning model. Machine learning models may be constructed by computers using training data sets. Thus, development of a machine learning model may include the training of the machine learning model using a training data set. In some cases (generally referred to as supervised learning), a training data set used to train a machine learning model can include known outcomes (e.g., labels or target values) for individual data samples in the training data set. For example, when training a supervised computer vision model to detect images of cats, a target value for a data sample in the training data set may indicate whether or not the data sample includes an image of a cat. In other cases (generally referred to as unsupervised learning), a training data set does not include known outcomes for individual data samples in the training data set.

[0097] Following development, a machine learning model may be used to generate inferences with respect to inference data sets. For example, following development, a computer vision model may be configured to distinguish data samples including images of cats from data samples that do not include images of cats. As used herein, the deployment of a machine learning model may refer to the use of a developed machine learning model to generate inferences about data other than the training data.

[0098] Artificial intelligence (AI) generally encompasses any technology that demonstrates intelligence. Applications (e.g., machine-executed software) that demonstrate intelligence may be referred to herein as artificial intelligence applications, AI applications, or intelligent agents. An intelligent agent may demonstrate intelligence, for example, by perceiving its environment, learning, and/or solving problems (e.g., taking actions or making decisions that increase the likelihood of achieving a defined goal). In many cases, intelligent agents are developed by organizations and deployed on network-connected computer systems so users within the organization can access them. Intelligent agents are used to guide decision-making and/or to control systems in a wide variety of fields and industries, e.g., security; transportation; risk assessment and management; supply chain logistics; and energy management. Intelligent agents may include or use models.

[0099] Some non-limiting examples of A1 application types may include inference applications, comparison applications, and optimizer applications. Inference applications may include any intelligent agents that generate inferences (e.g., predictions, forecasts, etc.) about the values of one or more output variables based on the values of one or more input variables. In some examples, an inference application may provide a recommendation based on a generated inference. For example, an inference application for a lending organization may infer the likelihood that a loan applicant will default on repayment of a loan for a requested amount, and may recommend whether to approve a loan for the requested amount based on that inference. Comparison applications may include any intelligent agents that compare two or more possible scenarios. Each scenario may correspond to a set of potential values of one or more input variables over a period of time. For each scenario, an intelligent agent may generate one or more inferences (e.g., with respect to the values of one or more output variables) and/or recommendations. For example, a comparison application for a lending organization may display the organization's predicted revenue over a period of time if the organization approves loan applications if and only if the predicted risk of default is less than 20% (scenario #1), less than 10% (scenario #2), or less than 5% (scenario #3). Optimizer applications may include any intelligent agents that infer the optimum values of one or more variables of interest based on the values of one or more input variables. For example, an optimizer application for a lending organization may indicate the maximum loan amount that the organization would approve for a particular customer.

[0100] Each numerical value presented herein, for example, in a table, a chart, or a graph, is contemplated to represent a minimum value or a maximum value in a range for a corresponding parameter. Accordingly, when added to the claims, the numerical value provides express support for claiming the range, which may lie above or below the numerical value, in accordance with the teachings herein. Absent inclusion in the claims, each numerical value presented herein is not to be considered limiting in any regard.

[0101] Particular embodiments of the subject matter have been described. Other embodiments are within the scope of the following claims. For example, the actions recited in the claims can be performed in a different order and still achieve desirable results. As one example, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In certain implementations, multitasking and parallel processing may be advantageous. Other steps or stages may be provided, or steps or stages may be eliminated, from the described processes. Accordingly, other implementations are within the scope of the following claims.

[0102] It will be appreciated by those skilled in the art that the preceding examples and embodiments are exemplary and not limiting to the scope of the present disclosure. It is intended that all permutations, enhancements, equivalents, combinations, and improvements thereto that are apparent to those skilled in the art upon a reading of the specification and a study of the drawings are included within the true spirit and scope of the present disclosure. It shall also be noted that elements of any claims may be arranged differently including having multiple dependencies, configurations, and combinations.

[0103] Having thus described several aspects of at least one embodiment of this invention, it is to be appreciated that various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be part of this disclosure, and are intended to be within the spirit and scope of the invention. Accordingly, the foregoing description and drawings are by way of example only.