Abstract:
In various embodiments, an apparatus for use in the recovery of unmanned underwater vehicles includes a recovery vehicle configured to be coupled to a winch via a tether. The recovery vehicle includes one or more sensors for locating the unmanned underwater vehicle, a first mechanical linking device for coupling the recovery vehicle to the unmanned underwater vehicle, and a plurality of steering mechanisms for actively guiding the unmanned underwater vehicle in such a way as to allow the first mechanical linking device to capture the unmanned underwater vehicle by locking onto a second mechanical linking device of the unmanned underwater vehicle.

Description:
FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT 
     This invention (Navy Case No. 099145) was developed with funds from the United States Department of the Navy. Licensing inquiries may be directed to the Office of Research and Technical Applications, Space and Naval Warfare Systems Center, San Diego, Code 2112, San Diego, Calif., 92152; voice 619-553-2778; email T2@spawar.navy.mil. 
    
    
     BACKGROUND 
     I. Field 
     This disclosure relates to systems and methods for the deployment and recovery of unmanned underwater vehicles. 
     II. Background 
     Unmanned underwater vehicles (UUVs) are forms of robots that travel underwater. Generally, UUVs include autonomous underwater vehicle (AUVs), which are devices that require no human control, and non-autonomous Remotely Operated underwater vehicles (ROVs), which are undersea vehicles that are controlled and powered from a remote location by an operator/pilot via an umbilical communications connection. 
     When UUVs are deployed, it becomes generally necessary to recover such devices. However, such recovery procedures can be extremely difficult, especially when the UUVs are autonomous devices having limited power or other resources (e.g., long-range underwater gliders), and no ready means to communicate with the outside world. Currently, launch and recovery operations of these assets are conducted with high risk to small boats, swimmer personnel and high-value equipment. Generally, a small boat or swimmer, in variable ocean conditions, must physically move to a UUV to attach a tow or lift line, or retrieve the vehicle by hand. This is extremely dangerous in high sea states. 
     With increasingly demanding requirements, the necessity to operate in higher sea states and from ships with differing freeboards, new recovery methods and devices for UUVs are desirable. 
     SUMMARY 
     Various aspects and embodiments of the invention are described in further detail below. 
     In a first series of embodiments, an apparatus for use in the recovery of unmanned underwater vehicles includes a recovery vehicle configured to be coupled to a winch via a tether. The recovery vehicle includes one or more sensors for locating the unmanned underwater vehicle, a first mechanical linking device for coupling the recovery vehicle to the unmanned underwater vehicle, and a plurality of steering mechanisms for actively guiding the unmanned underwater vehicle in such a way as to allow the first mechanical linking device to capture the unmanned underwater vehicle by locking onto a second mechanical linking device of the unmanned underwater vehicle. 
     In another series of embodiments, an apparatus for use in the recovery of unmanned underwater vehicles includes a recovery vehicle configured to be coupled to a winch via a tether. The recovery vehicle includes locating means for locating the unmanned underwater vehicle, linking means for coupling the recovery vehicle to the unmanned underwater vehicle, and steering means for actively guiding the unmanned underwater vehicle in such a way as to allow the linking means to capture the unmanned underwater vehicle by locking onto a second linking means of the unmanned underwater vehicle. 
     In another series of embodiments, a method for the recovery of unmanned underwater vehicles using a recovery vehicle coupled to a winch via a tether includes steering the recovery vehicle within an appreciably close range of the unmanned underwater vehicle using a remote steering system, a plurality of steering mechanisms of the recovery vehicle, and one or more first sensors of the recovery vehicle, placing the recovery vehicle into a capture mode, wherein when in the capture mode the recovery vehicle captures the unmanned underwater vehicle using a first mechanical linking device for coupling the recovery vehicle to the unmanned underwater vehicle and one or more sensors incorporated into the recovery vehicle configured to determine relative position of the unmanned underwater vehicle to the recovery vehicle, and retrieving both the recovery vehicle and unmanned underwater vehicle using the tether and winch. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features and nature of the present disclosure will become more apparent from the detailed description set forth below when taken in conjunction with the accompanying drawings in which reference characters identify corresponding items. 
         FIG. 1  is an exemplary unmanned underwater vehicle recovery system. 
         FIG. 2  depicts an unmanned underwater vehicle together with the recovery vehicle of  FIG. 1 . 
         FIG. 3  depicts an exemplary coupling and sensor configuration for the unmanned underwater vehicle together and recovery vehicle of  FIG. 2 . 
         FIG. 4  is a processing system for the recovery vehicle of  FIG. 3 . 
         FIG. 5  is a flowchart outlining an exemplary process for capturing an unmanned underwater vehicle. 
     
    
    
     DETAILED DESCRIPTION 
     The disclosed methods and systems below may be described generally, as well as in terms of specific examples and/or specific embodiments. For instances where references are made to detailed examples and/or embodiments, it should be appreciated that any of the underlying principles described are not to be limited to a single embodiment, but may be expanded for use with any of the other methods and systems described herein as will be understood by one of ordinary skill in the art unless otherwise stated specifically. 
       FIG. 1  is an exemplary unmanned underwater vehicle (UUV) recovery system  100 . As shown in  FIG. 1 , the UUV recovery system  100  includes a remote surface platform  110 , e.g., a ship, having a winch  120  and connected to an underwater Recovery Vehicle (RV)  130  via a tether  122 . The remote surface platform  110  floats on the surface of water  190 . 
     In operation, an operator at an operating center  112  on the remote surface platform  110  can deploy the RV  130  to search for a UUV, guiding the RV  130  through an area where a UUV is known or suspected to be. Note that the RV  130  may be guided and/or propelled using any number of mechanical devices, such as steerable water jets, steerable propellers, and one or more propellers with rudders. Also note that, in various other embodiments, the RV  130  may be propelled by virtue of being pulled by the remote surface platform  110  with steering accomplished using only a number of rudders/steering fins. Still also note that, in lieu of a human operator, the RV  130  may be guided automatically using sensors and computer control equipment located on platform  110  and/or on the RV  130 . 
     Continuing, the RV  130  may be guided to an appreciably close proximity of a UUV using any number of sensors to aid an operator, whether the operator be human or computer-based. Such sensors may include vision systems, such as cameras having low-light capability, sonar, LIDAR, magnetic sensors, EM sensors, and so on. While it is envisioned that such location sensors may be located within or on the RV  130 , in various embodiments some, part of some, or all of the sensors may be located on the remote platform  110 . For example, in an exemplary configuration, location of a UUV may be accomplished through a combination of an array of CCD array cameras on the RV  130 , an active sonar on the remote surface platform  110 , and a semi-active transponder system where a UUV responds to an sound or electro-magnetic (EM) pulse emitted by the remote surface platform  110  by emitting another sound and/or EM pulse that may be sensed by the RV  130 . 
     Once the RV  130  is guided to an appreciably close range to a UUV, the RV  130  may operate on an autonomous or semi-autonomous mode to capture the UUV as will be further explained below. Once captured, the UUV and RV  130  may be retrieved to the surface platform  110  via the winch  120  and tether  122 . 
       FIG. 2  depicts an exemplary UUV  230  together, i.e., within an appreciable range, of the exemplary RV  130  of  FIG. 1 . As shown in  FIG. 2 , the exemplary RV  130  includes a set of steering water jets  138  and a recovery apparatus  132  having internal control and communication electronics (not shown), a first set of sensing/communication devices  136  and a first mechanical capture device  134 . An alternative recovery apparatus  132 -ALT, may be used to demonstrate the idea that sensors and mechanical linkages may be located anywhere on the RV  130 . 
     In reference to  FIG. 2 , the exemplary UUV  230  includes internal control and communication electronics (not shown) and a mating spar  232 , which itself includes a second set of sensing/communication devices  236  and a second mechanical capture device  234 . Note that the exemplary “mating spar” shown in  FIG. 2  is to help demonstrate the different portions of the overall systems and is not intended to be limiting. For example, the exemplary second set of sensing/communication devices  236  may be directly incorporated into the body of the UUV  230 , and the second mechanical capture device  234  may extend directly from the body of the UUV  230 . 
     In operation, once the RV  130  and UUV  230  are within an appreciably close range, e.g., a range where the RV  130  might effectively sense the relative location and/or communicate with the UUV  230 , the RV  130  may work in an autonomous (or principally autonomous) mode where the RV  130  can use any number or combination of sensing devices, such as vision systems, LIDAR, RADAR, SONAR, laser-based scanning systems, magnetic sensors, EM sensors, transponders, and so on, to determine the relative location and possibly velocity of the UUV  230 . 
     Further, in various embodiments, the RV  130  may use any number or combination of communication devices capable of short-range (or longer) communication, such as EM/radio, laser or sound-based communication systems, to establish a communication link with the UUV  230  and possible establish control of the UUV&#39;s actions. For example, in various embodiments the RV  130  and UUV may establish a 2-way link using FM modulated radio signals so as to allow the RV  130  to take control of the UUV&#39;s speed and direction, thus allowing for a “closed-loop” controlled capture of the UUV  230 . 
     It should be appreciated that during operation coupling the RV  130  and UUV  230  may be done in a variety of ways. For example, the RV  130  may be made to “bump” the UUV  230  (or vice versa) head-on, tail-to-head, head-to-tail, or even couple from above or below. 
       FIG. 3  is a depiction of the forward spar  232  of the UUV of  FIG. 2  (along with the second set of sensing/communication devices  236  and the second mechanical capture device  234 ), as well as the aft/capture portion  132  of the RV  130  (along with the first set of sensing/communication devices  136 , the second mechanical capture device  134 , and a control module  138  for communication, operating sensors and interpreting sensor data, and conducting autonomous UUV  230  capture routines. Also depicted in  FIG. 3  are the various sensing and/or communication energies  310  emitted/provided by (or reflected off) the RV  130 , as well as are the various sensing and/or communication energies  320  emitted/provided by (or reflected off) the UUV  230 . 
     Still also shown in  FIG. 3 , the first and second mechanical capture devices  134  and  234  together include a ball-and-socket style connector having multiple degrees of freedom. That is, because an RV  130  and target UUV  230  may not be perfectly aligned and may have different pitch, yaw and roll angles relative to one another, a capture mechanism may benefit from a design that allows for such circumstances. Possible mechanical configurations of such ball-and-socket style connectors are known in the relevant arts, and specific examples of such devices can be found in U.S. Pat. No. 6,540,426 entitled “Passive ball capture joint”, U.S. Pat. No. 6,186,693 1 entitled “Passive capture joint with three degrees of freedom” and U.S. Pat. No. 2,755,105 entitled “BALL AND SOCKET COUPLING MECHANISM”, the contents of all of these patents being herein incorporated by reference in their entirety. 
     While the present example includes a ball-and-socket style coupling, it is to be appreciated that other types of connector/coupling systems may also be usable depending on various circumstances, such as the mass of a recovered UUV  230 . For example, it may be beneficial to use a magnetic coupling system, a suction-based coupler, an active moving mechanical coupling system capable of being pointed in different directions, and so on. 
     Continuing,  FIG. 4  is a control system  138  for the recovery vehicle of  FIG. 3 . As shown in  FIG. 4 , the exemplary control system  138  includes a controller  410 , a memory  420 , a sensor and transponder control device  430 , a ranging and direction device  440 , a guidance device  450 , control input/output circuitry  470 , communication input/output circuitry  480  and sensor/transponder input/output circuitry  490 . The above-components  410 - 490  are coupled together using control/data bus  402 . 
     Although the exemplary control system  138  of  FIG. 4  uses a bussed architecture, it should be appreciated that any other architecture may be used as is well known to those of ordinary skill in the art. For example, in various embodiments, the various components  410 - 490  can take the form of separate electronic components coupled together via a series of separate busses. 
     Still further, in other embodiments, one or more of the various components  410 - 490  can take form of separate processing systems coupled together via one or more networks. Additionally, it should be appreciated that each of components  410 - 490  advantageously can be realized using multiple computing devices employed in a cooperative fashion. 
     It also should be appreciated that some of the above-listed components  430 - 450  can take the form of software/firmware routines residing in memory  420  and be capable of being executed by the controller  410 , or even software/firmware routines residing in separate memories in separate computing systems being executed by different controllers. 
     It also should be appreciated from the discussion above that the control module  138  can accommodate both an autonomous and manual operation for both a searching mode of operation and a capture mode of operation. 
     For manual modes of operation, the control module  138  may be limited in its functionality to, e.g., merely collecting sensor and/or transponder data via the sensor/transponder input/output circuitry  490 , and forwarding such data to a remote operator via the communication input/output circuitry  480 . Such tasking may optionally include the interim processing of sensor and transponder data in order to provide an operator with enhanced data (e.g., provide relative position data (rather than raw data) and/or enhanced or compressed video), may also be provided by the control module  138 . Other processing in manual mode may include accepting commands from the remote operator via the communication input/output circuitry  480 , and controlling various propellers, control fins, water jets, and so on, based on such remote operator commands. 
     For automatic modes of operation, i.e., where no remote human operator is used, there are again two operational modes: a searching mode of operation and a capture mode of operation. 
     During the searching mode, under control of the controller  410  various sensors and/or transponders may be activated and controlled by the sensor/transponder control device  430  via the sensor/transponder input/output circuitry  490 . Accordingly, the resultant sensor/transponder data collected by sensors incorporated into the RV  130  may be imported by the sensor/transponder input/output circuitry  490 , and stored in memory  420 . Additionally, remote sensor data, such as sonar data provided by a remote surface platform, may be imported via the communication input/output circuitry  480  under control of the controller  410 , and also stored in memory  420 . Thereafter, the ranging and detection device  440  may use the various sensor and/or transponder data to search for a UUV  230  and provide a relative position of the UUV  230  to the guidance device  450 . Accordingly, the guidance device  450  may determine the appropriate commands to give whatever steering and propulsion mechanisms that the RV  130  has, and issue such commands to such steering and propulsion mechanisms until the RV  130  comes within an appreciable proximity to the UUV  230 . 
     After the RV  130  is in proximity of the UUV  230 , the control module  138  may enter a capture mode in order to mechanically couple the RV  130  to the UUV  230  via a mechanical coupling system, such as the ball-and-socket joints discussed above. Upon entering the capture mode, the control module  138  may use the same set of sensors used for steering mode, or may employ other sensors more suitable for determining relative location in finer increments of angle and/or distance. For example, in a steering mode the control module  138  may use remotely provided sonar data, but switch to combination local vision system and laser-based scanning system to determine relative UUV  230  position once in capture mode. 
     Additionally, the controller  410  may optionally make direct communication with the UUV  230  using the communication input/output circuitry  480  and a short-range communication system incorporated into both the RV  130  and UUV  230 , such as a two-way EM radio or infrared laser-based communication device. Again, as mentioned before, such a communication interface may be used to control the actions of the UUV  230  in order to provide a closed-loop control system to more precisely guide a mechanical coupling on the UUV  230  to a complementary mechanical coupling device on the RV  130 . Again, the sensor/transponder control device  430 , the ranging and detection device  440 , and the guidance device  450  may be used to control sensors, collect sensor data, determine relative position and determine the appropriate guidance commands to issue to either or both the RV  130  and UUV  230 . 
       FIG. 5  is a flowchart outlining an exemplary process for capturing an unmanned underwater vehicle. The process starts in step  502  where an RV  130  may be deployed to recover/capture a UUV  230 . Next, in step  504 , the RV  130  may be steered to an appreciable proximity of the UUV  230  using one or more first sensors under control of a human or (optionally) a computer-based operator. Again, as mentioned above, sensors deployed on a surface platform  110  or on the RV  130  may be used to facilitate guidance. Then, in step  506 , assuming that the RV  130  is in such an appreciable distance that local sensors and/or communication devices may be effectively used with the UUV  230 , the appropriate sensors/transponders and communication links may be activated. Control continues to step  508 . 
     In step  508 , sensor/transponder data of sensors incorporated in the RV  130 , as well as remote sensor data, may be accumulated and stored. Additional data, such as telemetry data derived by the UUV  230  and sent over the appropriate communication link, may also be collected and stored. For example, while the RV  130  may use a local sonar and vision system to determine relative position of the RV  130  to the UUV  230 , relative velocity data may be derived using RV  130 -based velocity sensors and velocity sensors, e.g., gyroscopes, incorporated into the UUV  230  and sent over the appropriate communication link. Next, in step  510 , relative direction, (optional) velocity and ranging information may be derived, and in step  512  the appropriate guidance commands may be derived for either or both the RV  130  and UUV  230 . Control continues to step  514 . 
     In step  514 , the guidance commands derived in step  512  may be issued and performed by the RV  130  and/or UUV  230  so as to guide a mechanical coupling of the UUV  230  to a complementary coupling device on the RV  130 . Next, in step  520 , a determination is made as to whether the RV  130  and UUV  230  are securely coupled. If the RV  130  and UUV  230  are securely coupled, then control continues to step  522 ; otherwise, control jumps back to step  508  where after steps  508 - 520  can be repeated as necessary. 
     In step  522 , the RV  130  and UUV  230  may be redeployed to a remote surface platform  110  via a winch  120  and tether  122  until the RV  130  and UUV  230  are secured to the surface platform  110 , and control continues to step  550  where the process stops. 
     In various embodiments where the above-described systems and/or methods are implemented using a programmable device, such as a computer-based system or programmable logic, it should be appreciated that the above-described systems and methods can be implemented using any of various known or later developed programming languages, such as “C”, “C++”, “FORTRAN”, Pascal”, “VHDL” and the like. 
     Accordingly, various storage media, such as magnetic computer disks, optical disks, electronic memories and the like, can be prepared that can contain information that can direct a device, such as a computer, to implement the above-described systems and/or methods. Once an appropriate device has access to the information and programs contained on the storage media, the storage media can provide the information and programs to the device, thus enabling the device to perform the above-described systems and/or methods. 
     For example, if a computer disk containing appropriate materials, such as a source file, an object file, an executable file or the like, were provided to a computer, the computer could receive the information, appropriately configure itself and perform the functions of the various systems and methods outlined in the diagrams and flowcharts above to implement the various functions. That is, the computer could receive various portions of information from the disk relating to different elements of the above-described systems and/or methods, implement the individual systems and/or methods and coordinate the functions of the individual systems and/or methods related to communications. 
     What has been described above includes examples of one or more embodiments. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the aforementioned embodiments, but one of ordinary skill in the art may recognize that many further combinations and permutations of various embodiments are possible. Accordingly, the described embodiments are intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims. Furthermore, to the extent that the term “includes” is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term “comprising” as “comprising” is interpreted when employed as a transitional word in a claim.