EXTERNAL PAYLOAD CARRIER FOR UNDERWATER VEHICLE

Abstract

A technique for carrying a payload by a UUV includes providing a structure that extends around an outer surface of the UUV along a length of the UUV. The structure has an outer membrane that forms a streamlined shape around the UUV and contains the payload.

Description

BACKGROUND

UUVs (unmanned underwater vehicles) are commonly used for exploring and monitoring underwater environments and for carrying payloads to underwater locations. A typical UUV includes sensors and a location service, such as GPS (Global Positioning Service) and/or DVL (Doppler Velocity Log). Typical payloads include sensors, munitions, and other cargo.

SUMMARY

Unfortunately, adapting UUVs for carrying various payloads can be engineering-intensive and mission-specific. Indeed, different sizes or configurations of payloads may require different UUV designs, which may involve constructing modifications for inserting payloads into a main body of a UUV. Some have attempted to attach payloads to external UUV surfaces, e.g., using straps or bungee cords, but doing so introduces a host of design issues, including impaired hydrodynamics and imbalanced drag characteristics. What is needed, therefore, is a more versatile approach for carrying payloads by a UUV that is general purpose and does not impair mobility.

The above need is addressed at least in part by an improved technique for carrying a payload by a UUV. The technique includes providing a structure that extends around an outer surface of the UUV along a length of the UUV. The structure has an outer membrane that forms a streamlined shape around the UUV and contains the payload.

Advantageously, the structure can be engineered once for accommodating a variety of payloads of different sizes and shapes. The streamlined shape of the outer membrane ensures consistent and efficient hydrodynamic performance even as payloads are changed. Little or no design or engineering expertise is required of operators for provisioning a UUV with a wide range of payloads.

Certain embodiments are directed to a structure for carrying payloads of a UUV (unmanned underwater vehicle). The structure includes an outer membrane constructed and arranged to (i) extend around an outer surface of the UUV along a length of the UUV, (ii) contain a payload, and (iii) form a streamlined shape around the UUV.

In some examples, the outer membrane includes a tensioned wrap that extends around the payload on one side of the UUV and around a spacer on an opposite side of the UUV.

In some examples, the streamlined shape is symmetrical about at least one plane.

In some examples, the outer membrane is constructed and arranged to form the streamlined shape when an enclosed region between the UUV and the outer membrane is inflated with fluid.

In some examples, the streamlined shape of the outer membrane when inflated with the fluid is tapered toward the UUV at first and second ends of the outer membrane.

In some examples, the outer membrane is constructed and arranged to assume a predetermined shape when the enclosed region is inflated with the fluid.

In some examples, the outer membrane is composed of multiple panels stitched or otherwise fused together.

In some examples, the structure further includes an inner membrane constructed and arranged to conform to the outer surface of the UUV, the enclosed region being disposed between the inner membrane and the outer membrane.

In some examples, the inner membrane forms a water-impermeable seal with the outer membrane at the first and second ends of the outer membrane.

In some examples, the inner membrane and the outer membrane form a watertight container that surrounds the enclosed region.

In some examples, the outer membrane when inflated with the fluid forms an interior space arranged to contain the payload, and the interior space has an opening through which the payload can controllably be ejected into surrounding water.

In some examples, the outer membrane is folded in on itself to form the opening of the interior space. The opening is normally closed to contain the payload and to provide a continuous outer surface of the structure directly outside the interior space.

In some examples, the continuous outer surface is symmetrical with an outer surface of the outer membrane on a diametrically opposite side of the structure.

In some examples, the structure further includes an actuator constructed and arranged to eject the payload through the opening.

In some examples, the actuator is constructed and arranged to eject the payload at a velocity sufficient to enable control surfaces of the payload to influence a path of the payload through the surrounding water.

In some examples, the structure further includes a communications interface constructed and arranged to communicate with the UUV and to eject the payload through the opening in response to a command from the UUV.

In some examples, the structure has a tunable buoyancy.

Other embodiments are directed to an apparatus that includes a UUV (unmanned underwater vehicle) having a length and an outer surface, and a structure applied around the outer surface along at least a portion of the length, the structure including an outer membrane constructed and arranged to (i) extend around an outer surface of the UUV along a length of the UUV, (ii) contain a payload, and (iii) form a streamlined shape around the UUV.

Still other embodiments are directed to a method of carrying and/or deploying external payloads by a UUV (unmanned underwater vehicle). The method includes applying a structure around an outer surface of the UUV, the structure including an outer membrane constructed and arranged (i) to extend around an outer surface of the UUV along a length of the UUV and (ii) to form a streamlined shape around the UUV. The method further includes inserting a payload into the structure and filling the inflatable region with fluid such that the structure forms a streamlined shape around the UUV and contains the payload.

In some examples, the method further includes deploying the UUV within a body of water, receiving, by a communications interface within the structure, a command from the UUV to release the payload, and releasing the payload in response to the command. Releasing the payload in response to the command is responsive to determining a time at which to release the payload based on a current location of the UUV within the body of water and a location of a desired target.

The foregoing summary is presented for illustrative purposes to assist the reader in readily grasping example features presented herein; however, this summary is not intended to set forth required elements or to limit embodiments hereof in any way. One should appreciate that the above-described features can be combined in any manner that makes technological sense, and that all such combinations are intended to be disclosed herein, regardless of whether such combinations are identified explicitly or not.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The foregoing and other features and advantages will be apparent from the following description of particular embodiments, as illustrated in the accompanying drawings, in which like reference characters refer to the same or similar parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of various embodiments.

FIG. 1 is a front-side view of an example UUV having a structure for carrying an external payload.

FIG. 2 is a top-left perspective view of an example structure of FIG. 1.

FIG. 3 is a cross-sectional view of a UUV and structure according to a first embodiment.

FIG. 4 is a cross-sectional view of a UUV and structure according to a second embodiment.

FIG. 5 is a flowchart showing an example method of carrying and/or deploying external payloads by a UUV.

DETAILED DESCRIPTION

Embodiments of the improved technique will now be described. One should appreciate that such embodiments are provided by way of example to illustrate certain features and principles but are not intended to be limiting.

An improved technique for carrying a payload by a UUV (unmanned underwater vehicle) includes providing a structure that extends around an outer surface of the UUV along a length of the UUV. The structure has an outer membrane that forms a streamlined shape around the UUV and contains the payload.

FIG. 1 shows an example UUV 100 with which embodiments of the improved technique can be practiced. Here, the depicted UUV 100 has a length 102, a nose 104, and a tail 106. A propeller may be mounted to the tail 106. The depicted UUV 100 has a substantially cylindrical shape, which is defined by an outer surface 108. One should appreciate that UUV designs can vary, however. Some may have different shapes from the one shown, and some may have tail fins. The illustrated UUV 100 is merely an example.

As further shown in FIG. 1, a structure 110 is applied to the UUV 100 around the outer surface 108. The structure 110 is constructed and arranged to contain a payload 120. FIG. 1 shows an example cylindrical payload 120 in three states of deployment from the UUV 100. The depicted payload 120 may have one or more control surfaces 122 to guide it through water along a controlled, predictable path. The payload 120 may have any shape and features, however, and it may have a range of sizes and masses. Although the depicted payload is deployable from the structure 110, other payloads may be non-deployable, e.g., certain payloads may be designed to remain within the structure 110.

The structure 110 may be placed at any desired location along the length 102 of the UUV 110. Structures 110 that are larger or smaller than the one shown may be provided, and multiple structures may be applied at different locations along the length 102. Preferably, the structure 110 is placed such that it does not interfere with sensors within the UUV 100. The structure 110 is further placed such that it has a minimal impact on mobility and maneuverability of the UUV 100, e.g., by placing the structure 110 near a center of mass of the UUV 100.

Preferably, the structure 110 is streamlined to promote efficient hydrodynamics and to minimize drag. The structure 110 preferably has uniform drag characteristics, so that the UUV 100 does not veer in any direction when under way. The structure 110 also preferably has a defined, stable external shape, which is maintained at all expected speeds through water. Ideally, the structure 110 has minimal impact on the handling and control characteristics of the UUV 100. For example, a control system of the UUV 100 may require few if any modifications for accommodating the structure 110. If the control system does require modifications, such modifications would need to be made only once for use with a particular structure 110 (assuming the location of the structure 110 does not change), even if payloads of different sizes and/or shapes are provided. The structure 110 preferably has controllable initial buoyancy, which may be adjusted, for example, through the use of floats or ballasts, and/or by filling internal spaces of the structure 110 with various fluids, such as with water of different salinities.

FIG. 2 shows an example structure 110 in additional detail. The illustrated structure 110 has an outer membrane 220 having a defined shape. The outer membrane 220 has a first end 110a and a second end 110b, as well as a top 220t and a bottom 220b. The outer membrane 220 is sized and arranged to fit against the outer surface 108 of a UUV at the first end 110a and the second end 110b. Although the first end 110a and the second end 110b are described as ends of the outer membrane 220, one can see that they also identify respective ends of the structure 110 overall.

The outer membrane 220 has a streamlined shape, which tapers down at the ends 110a and 110b and bulges out from a central axis 202 in the middle. In some examples, the bulging can be tuned to optimize drag, size, length, volume, shape, and/or mass characteristics. In an example, a space within the bottom region 220b contains a payload 120, and an opposite space within the top region 220t contains a spacer or other material, which in some examples may be fluid. Preferably, the top and bottom regions 220t and 220b are symmetrically shaped, such that they induce equal drag and keep the overall drag forces of the structure 110 coincident with the central axis 202. In some examples, the outer membrane is composed of multiple panels, which may be stitched or otherwise fused together. The upper spacer within the top region 220t is not required in some embodiments, as the carrier UUV may have the ability to accommodate a non-symmetric addition of volume and drag surfaces, or a given payload might not require it for balancing hydrodynamic loads.

Some embodiments may further include an inner membrane 210, which is constructed and arranged to conform to the outer surface 108 of a UUV and to be held tightly against the surface 108 by friction. In such examples, the inner membrane 210 may be joined with the outer membrane 220 at the first and second ends 110a and 110b.

The example of FIG. 2 is intended to be applicable to the embodiments shown in both FIGS. 3 and 4. Those embodiments and their similarities and differences will now be explained.

FIG. 3 shows a first embodiment of an example structure 110 applied around an example UUV 100. In this cross-sectional view, the structure 110 includes both an inner membrane 210 and an outer membrane 220. The inner membrane 210 extends around the outer surface 108 of the UUV 100, where the inner membrane 210 is held in place by friction. Alternatively, a positive attachment may be provided. Friction has been found to be sufficient, however, for maintaining location and orientation of the structure on the UUV outer surface 108. The outer membrane 220 extends around the inner membrane 210. No direct attachment can be seen between the inner membrane 210 and the outer membrane 220, but the two membranes are fused together at the ends 110a and 110b (FIG. 2). An enclosed region 310 is formed between the inner membrane 210 and the outer membrane 220.

In this embodiment, the inner membrane 210 is composed of a liquid-impermeable material, which may be flexible. The outer membrane 220 is also composed of a liquid impermeable material, which may be flexible, but it is also preferably inextensible, such that it does not stretch under expected pressures. Examples of suitable materials for both membranes may include polyester sheets, rubber-infiltrated fabrics, and the like.

In this embodiment, the enclosed region 310 provides a liquid-tight container between the first membrane 210 and the second membrane 220, and the container formed by the enclosed region 310 may be filled with fluid. For example, fluid may be pumped from an external source via a fluid coupling 370. The fluid may be gas or liquid, such as water. Water of a particular salinity may be chosen for providing a desired level of buoyancy. In some examples, the fluid may simply be seawater pumped into the enclosed region 310 prior to launch.

As can be seen, the fluid can flow completely around the UUV 100, equalizing pressure in all contained regions. Provided that all air has been evacuated, the structure once filled with liquid becomes incompressible and can withstand substantial depths in water. Preferably, sufficient pressure is achieved to inflate the outer membrane 220, such that it assumes the predefined shape (e.g., FIG. 2) and maintains that shape under varying conditions and at speed. The applied pressure also pushes the inner membrane 210 firmly against the outer surface 108 of the UUV, strengthening the frictional engagement.

As further shown, the outer membrane 220 has a top region 220a and a bottom region 220b. The bottom region 220b includes a payload 120 and associated componentry. The top region 220a is empty in this example, but alternative arrangements could include a spacer and/or ballast in this region. In further arrangements, asymmetry is permitted and the top region 220a conforms to the inner membrane 210 (no space is provided).

Looking at the bottom of FIG. 3, an example mechanism is shown for containing and selectively deploying the payload 120. Here, the bottom 220b of the outer membrane 220 is split into first and second jaws, 320a and 320b. The jaws 320a and 320b are normally closed, such that a bottom surface 360 of the structure 110 is closed and continuous. For example, the bottom surface 360 has substantially the same shape as a diametrically opposite top surface 360a, which is a continuous material that is not able to open. The first and second jaws 320a and 320b define an interior space 330, which contains the payload 120 and the associated componentry.

In the example shown, an actuator 350 is configured to eject the payload 120 from the structure 110. For example, the actuator 350 pushes down on the payload 120, causing the jaws 320a and 320b to open and causing the payload 120 to pass through. Once the payload 120 has exited through the opening formed between the opposing jaws 320a and 320b, the jaws close back to their original positions, shutting the opening and restoring the original shape.

In some examples, the actuator 350 ejects the payload 120 at a velocity and trajectory sufficient to enable control surfaces 122 (FIG. 1) of the payload 120 to influence a path of the payload 120 through the surrounding water. This feature helps to prevent the payload 120 from bumping into tail fins or propellers of the UUV 100. It also promotes a predictable descent of the payload 120 through the surrounding water, which can be useful if the payload 120 is intended to intersect a desired target or location.

In some examples, the actuator 350 operates in response to a command 390 issued by the UUV 100. To this end, the UUV 100 may include electronic control circuitry, such as a processor 380, memory 382, a wireless communications interface 384, and location services 386, such as GPS and/or DVL. The UUV 100 may operate its control circuitry to time the deployment of the payload 120. For example, the memory 382 may store a program which, when executed by the processor 380, calculates a time and location at which to drop the payload 120. The program may base its determination of time and location on the current location of the UUV 100 (e.g., latitude, longitude, and depth) and on a known location of a desired target. When the determined time for dropping the payload 120 arrives, the processor 380 directs the communications interface 384 to send the command 390. The command 390 travels a short distance and is received by a communications interface 340 within the structure 110, e.g., within the interior space 330. Preferably, the communications interface 340 is placed close to the inner membrane 210, such that there is little water or other fluid between the two interfaces 384 and 340 that could attenuate the wireless signal. It is noted that this use of wireless communications between the UUV 100 and the interface 340 avoids the need to pass cables through the wall of the UUV or through the membranes.

Although not shown, a power source (e.g., a battery), is assumed to be present for powering the interface 340. The actuator 350 may also require power. In some examples, the actuator 350 is spring-loaded. For instance, an operator loading the payload 120 may compress a spring of the actuator 350 and engage a latch, such that the payload 120 can be ejected with significant force just by releasing the latch and allowing the spring to expand.

One should appreciate that various mechanisms for containing and releasing payloads are contemplated. Thus, the example shown is intended to be illustrative rather than limiting.

FIG. 4 shows a second embodiment of an example structure 110 applied around an example UUV 100. In the cross-sectional view of FIG. 4, the structure 110 includes an outer membrane 220 but no inner membrane 210. Rather than holding its shape based on fluid pressure, as in FIG. 3, the outer membrane 220 of FIG. 4 holds its shape based on tension. The tension may be applied by one or more springs, which may be provided along a seam 470. Additionally or alternatively, the material from which the outer membrane 220 is composed may itself have an elastic character. In this example, the outer membrane 220 may be provided as a sheet that may be wrapped around the UUV, with the two ends of the sheet fastened together at the seam 470. There is no need in this embodiment for the outer membrane 220 to be liquid-impermeable.

In this arrangement, the defined shape of the outer membrane 220 is maintained using spacers 410 and 420, such as bladders, foam, or other components or materials. If bladders are used, such bladders may be filled with fluid, such as water, air or any other liquid or gas, or any combination of liquids and/or gases as needed to establish desired buoyancy and compression resistance. Deployment of a payload 120 may proceed similarly to that described in connection with FIG. 3 above.

FIG. 5 shows an example method 500 of carrying and/or deploying external payloads by a UUV 100. The method 500 may be performed, for example, by a human operator of the UUV (or a robot, machine, etc.), by a remote operator, by the UUV, and/or by the structure 110 itself. Although the acts of method 500 are shown as occurring in a certain order, that order is presented herein as an example and may be varied.

At 510, a structure 110 is applied to the outer surface 108 of the UUV 100. With the embodiment of FIG. 3, the structure 110 may be applied over the nose 114 of the UUV 110 and slid partway down the length 102 of the UUV 100 to a desired location, which is preferably clear of any sensors or control surfaces, and which does not excessively disrupt the maneuverability of the UUV 100. With the embodiment of FIG. 4, the structure 110 may be applied by wrapping the outer membrane 220 around the UUV 100 at a desired location along the length 102, inserting the spacers 410 and 420 if needed, and closing a seam 470 that joins the two ends of the membrane 220 together. The seam 470 may be tied, zippered, or fastened in any suitable way.

At 520, a payload 120 may be inserted into the structure 110. For example, a payload 120 may be slid into the interior region 330 from an end of the structure 110 and pushed forward to a desired position. If a spring-loaded actuator 350 is used, the spring may be compressed such that the actuator 350 becomes armed. Alternatively, the payload 120 may be inserted during step 510, or at a later time.

Step 530 applies only to the FIG. 3 embodiment. Here, the enclosed region 320 is inflated with fluid, pressurizing the outer membrane 220 and pushing the inner membrane 210 against the outer surface 108 of the UUV 100. The outer membrane 220 thus assumes the predefined shape. Pressurizing fluid may be obtained from seawater at the launch site, or it may be provided from other sources.

At 540, with the structure 110 applied (and pressurized, if needed) and the payload 120 inserted, the UUV 100 is deployed in the water at the launch site. The UUV 100 then proceeds through the water on its mission. One should appreciate that the UUV may be deployed from shore, from a ship at sea, from a submarine, or from any other location.

At 550, the structure 110 receives a command to release the payload 120. For example, the UUV 100 may compute a time and location for dropping the payload 120. When the time arrives at the determined location, the UUV 110 issues a command 390 via the wireless interface 384. The interface 340 within the structure 110 then receives the command 390.

At 360, in response to the command 390, the structure 110 and triggers or otherwise activates the actuator 350, causing the actuator 350 to force the payload 120 out of the structure 110 and along a descent path.

An improved technique has been described for carrying a payload 120 by a UUV 100. The technique includes providing a structure 110 that extends around an outer surface 108 of the UUV along a length 102 of the UUV. The structure has an outer membrane 220 that forms a streamlined shape around the UUV 100 and contains the payload 120.

Advantageously, the structure 110 can be engineered once for accommodating a variety of payloads 120 of different sizes and shapes. The streamlined shape of the outer membrane 220 ensures consistent and efficient hydrodynamic performance even as payloads 120 are changed. Little or no design or engineering expertise is required of operators for provisioning a UUV 100 with a wide range of payloads.

Having described certain embodiments, numerous alternative embodiments or variations can be made. For example, although the FIG. 3 embodiment uses both an inner membrane 210 and an outer membrane 220, some variants of this embodiment may dispense with the inner membrane 210. For example, the outer membrane 220 may be adhered to the outer surface 108 of the UUV 100 at the first and second ends 110a and 110b, effectively forming a sealed compartment bounded from below by the UUV and bounded from above by the second membrane 220.

Further, although features have been shown and described with reference to particular embodiments hereof, such features may be included and hereby are included in any of the disclosed embodiments and their variants. Thus, it is understood that features disclosed in connection with any embodiment are included in any other embodiment.

As used throughout this document, the words “comprising,” “including,” “containing,” and “having” are intended to set forth certain items, steps, elements, or aspects of something in an open-ended fashion. Also, as used herein and unless a specific statement is made to the contrary, the word “set” means one or more of something. This is the case regardless of whether the phrase “set of” is followed by a singular or plural object and regardless of whether it is conjugated with a singular or plural verb. Also, a “set of” elements can describe fewer than all elements present. Thus, there may be additional elements of the same kind that are not part of the set. Further, ordinal expressions, such as “first,” “second,” “third,” and so on, may be used as adjectives herein for identification purposes. Unless specifically indicated, these ordinal expressions are not intended to imply any ordering or sequence. Thus, for example, a “second” event may take place before or after a “first event,” or even if no first event ever occurs. In addition, an identification herein of a particular element, feature, or act as being a “first” such element, feature, or act should not be construed as requiring that there must also be a “second” or other such element, feature or act. Rather, the “first” item may be the only one. Also, and unless specifically stated to the contrary, “based on” is intended to be nonexclusive. Thus, “based on” should be interpreted as meaning “based at least in part on” unless specifically indicated otherwise. Although certain embodiments are disclosed herein, it is understood that these are provided by way of example only and should not be construed as limiting.

Those skilled in the art will therefore understand that various changes in form and detail may be made to the embodiments disclosed herein without departing from the scope of the following claims.

Claims

1. A structure for carrying payloads of a UUV (unmanned underwater vehicle), comprising: an outer membrane constructed and arranged to (i) extend around an outer surface of the UUV along a length of the UUV, (ii) contain a payload, and (iii) form a streamlined shape around the UUV.

2. The structure of claim 1, wherein the outer membrane includes a tensioned wrap that extends around the payload on one side of the UUV and around a spacer on an opposite side of the UUV.

3. The structure of claim 1, wherein the streamlined shape is symmetrical about at least one plane.

4. The structure of claim 1, wherein the outer membrane is constructed and arranged to form the streamlined shape when an enclosed region between the UUV and the outer membrane is inflated with fluid.

5. The structure of claim 4, wherein the streamlined shape of the outer membrane when inflated with the fluid is tapered toward the UUV at first and second ends of the outer membrane.

6. The structure of claim 4, wherein the outer membrane is constructed and arranged to assume a predetermined shape when the enclosed region is inflated with the fluid.

7. The structure of claim 6, wherein the outer membrane is composed of multiple panels stitched or otherwise fused together.

8. The structure of claim 6, further comprising an inner membrane constructed and arranged to conform to the outer surface of the UUV, the enclosed region being disposed between the inner membrane and the outer membrane.

9. The structure of claim 8, wherein the inner membrane forms a water-impermeable seal with the outer membrane at the first and second ends of the outer membrane.

10. The structure of claim 8, wherein the inner membrane and the outer membrane form a watertight container that surrounds the enclosed region.

11. The structure of claim 8, wherein the outer membrane when inflated with the fluid forms an interior space arranged to contain the payload, the interior space having an opening through which the payload can controllably be ejected into surrounding water.

12. The structure of claim 11, wherein the outer membrane is folded in on itself to form the opening of the interior space, the opening normally being closed to contain the payload and to provide a continuous outer surface of the structure directly outside the interior space.

13. The structure of claim 12, wherein the continuous outer surface is symmetrical with an outer surface of the outer membrane on a diametrically opposite side of the structure.

14. The structure of claim 11, further comprising an actuator constructed and arranged to eject the payload through the opening.

15. The structure of claim 14, wherein the actuator is constructed and arranged to eject the payload at a velocity sufficient to enable control surfaces of the payload to influence a path of the payload through the surrounding water.

16. The structure of claim 11, further comprising a communications interface constructed and arranged to communicate with the UUV and to eject the payload through the opening in response to a command from the UUV.

17. The structure of claim 1 wherein the structure has a tunable buoyancy.

18. An apparatus, comprising: a UUV (unmanned underwater vehicle) having a length and an outer surface; anda structure applied around the outer surface along at least a portion of the length, the structure including an outer membrane constructed and arranged to (i) extend around an outer surface of the UUV along a length of the UUV, (ii) contain a payload, and (iii) form a streamlined shape around the UUV.

19. A method of carrying and/or deploying external payloads by a UUV (unmanned underwater vehicle), comprising: applying a structure around an outer surface of the UUV, the structure including an outer membrane constructed and arranged (i) to extend around an outer surface of the UUV along a length of the UUV and (ii) to form a streamlined shape around the UUV;inserting a payload into the structure; andfilling the inflatable region with fluid such that the structure forms a streamlined shape around the UUV and contains the payload.

20. The method of claim 19, further comprising: deploying the UUV within a body of water;receiving, by a communications interface within the structure, a command from the UUV to release the payload; andreleasing the payload in response to the command,wherein releasing the payload in response to the command is responsive to determining a time at which to release the payload based on a current location of the UUV within the body of water and a location of a desired target.