Patent Grant
9586661
Unmanned underwater vehicles (UUVs) are very capable of mapping and inspecting sections of sea floors or harbors. They are currently incapable of repeatedly bottoming themselves into mud-like sea floors and separating due to being suctioned to the sea floor. Bottoming is a term that refers to the intentional contact with the bottom of a body of water and the arresting of motion in that location at the bottom of a body of water. The mud, at the bottom of the sea floor or harbor, places a suction force on any bottomed object, and actively resists separation. There is a need for an improved UUV design that provides the capability of countering these suction forces and allowing for separation from the sea floor.
Prior systems aimed at avoiding the sea floor altogether to prevent the vehicle from adhering to the mud or to prevent damage to a UUV. This device provides a UUV with a new capability of bottoming into mud and successfully separating.
Reference in the specification to “one embodiment” or to “an embodiment” means that a particular element, feature, structure, or characteristic described in connection with the embodiments is included in at least one embodiment. The appearances of the phrases “in one embodiment,” “in some embodiments,” and “in other embodiments” in various places in the specification are not necessarily all referring to the same embodiment or the same set of embodiments.
Some embodiments may be described using the expression “coupled” and “connected” along with their derivatives. For example, some embodiments may be described using the term “coupled” to indicate that two or more elements are in direct physical or electrical contact. The term “coupled,” however, may also mean that two or more elements are not in direct contact with each other, but yet still co-operate or interact with each other. The embodiments are not limited in this context.
As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Further, unless expressly stated to the contrary, “or” refers to an inclusive or and not to an exclusive or.
Additionally, use of the “a” or “an” are employed to describe elements and components of the embodiments herein. This is done merely for convenience and to give a general sense of the invention. This detailed description should be read to include one or at least one and the singular also includes the plural unless it is obviously meant otherwise.
This Unmanned Underwater Vehicle (UUV) Sea Floor Separation Device provides the capability for a UUV to repeatedly separate itself from the sea floor. In one embodiment, the device is comprised of a first plate positioned on top of and parallel to a second plate, where the first plate and second plate are separated by a spacer, and a pump. The pump draws water from an outside system, such as the surrounding sea, at ambient pressure, into the space created by the spacer situated between the two parallel plates. The top plate has no perforations, but the bottom plate is partially or fully perforated with a plurality of pin-sized holes or openings, which allow fluid to seep out or be forced out with the pump. There are several potential embodiments of the pattern of the pin-sized holes—they need not be spotted in a uniform or matrix-like pattern, but could be arranged in a spoke-hub type fashion so as to facilitate water intrusion towards the underbody, or any other design as would be recognized by one having ordinary skill in the art. For example, in one embodiment, the holes make up an X-like pattern on the bottoming plate, and in another embodiment the holes make up a starfish-like pattern on the bottoming plate. In both embodiments, the water can be concentrated in such a way as to invite water seepage into the mud (vs. uniformly spaced matrix of holes).
In one embodiment, the plates are coupled to the UUV, either via screws or nails or a similar mechanism for attachment. The UUV can either have a flat bottom or a curved bottom, and the plates would either be curved or straight depending on the corresponding UUV's structure. The holes can be arranged similarly for either shape, and arranging the holes in a line that follows the circumference of the plates naturally allows seawater to seek out and invade the vacuum pocket that is holding the vehicle in the mud. The starfish shape or X shape allows fluid to be forced out of the holes and can facilitate having one corner or edge separate first. If just one corner or edge could separate first, seawater would intrude and assist in separation.
The spacer plate separates the top and bottom plates by a fixed distance dictated by the thickness of the spacer plate. The spacer plate can be thought of as a gasket, and fits around the perimeter of the top and bottom plates creating a seal between the two parallel plates and creating a void for water to be pumped into. The flooded void is just slightly pressurized above ambient sea pressure when water is pumped into the vacant water space between the parallel plates.
The pump can be located within the UUV, outside the UUV, onboard the separation system, or any other location as would be recognized by one having ordinary skill in the art. The pump can be a peristaltic pump, diaphragm pump, rotary pump, or another similar pump.
The pressurized water, once pumped into the void space between the top and bottom plates, only has one option to exit and keep the system in hydrostatic balance. The pressurized water in the void space exits through the multitude of perforated pin-sized holes in the bottom plate. If the bottom plate is in contact with the mud on the bottom of the sea floor, the exiting water is capable of eroding the mud beneath the exit of the holes. Eventually, enough mud will be eroded beneath the bottom plate to reduce the suction force from the mud to a state that the system can fully separate. In this embodiment, the force to lift the system off the mud, once the suction force is reduced, comes from positive buoyancy of the system. This can be created with ballasting, a buoyancy engine, or a plurality of methods.
The Unmanned Underwater Vehicle (UUV) Sea Floor Separation Device is assigned to the United States Government and is available for licensing for commercial purposes. Licensing and technical inquiries may be directed to the Office of Research and Technical Applications, Space and Naval Warfare Systems Center, Pacific, Code 72120, San Diego, Calif., 92152; voice (619) 553-5118; email ssc_pac T2@navy.mil. Reference Navy Case Number 102371.
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