Magnetically actuated high-pressure valve

Abstract

A hydraulic system includes an outer magnetic coupler positioned about an inner magnetic coupler, a motor having a shaft configured to rotate the outer magnetic coupler, and a drive shaft longitudinally movable via rotation of the inner magnetic coupler. A poppet valve is configured to unseat from a sealed state in response to longitudinal movement of the drive shaft. The rotation of the outer magnetic coupler causes rotation of the inner magnetic coupler.

Description

Docket No.569.0001 MAGNETICALLY ACTUATED HIGH-PRESSURE VALVE TECHNICAL FIELD

[0001] Embodiments of the present invention relate to oceanic data collection, and more particularly to apparatus and methods of controlling buoyancy in autonomous profiling floats and gliders. BRIEF STATEMENT

[0002] Autonomous underwater vehicles (AUVs) such as autonomous profiling floats are revolutionizing the way scientists study the ocean. Before the first profiling float entered the water, our ability to measure climate, biological and chemical trends was limited in scope while large-scale studies were a costly endeavor. Today, scientists monitor the world’s oceans with thousands of floats. These developments have provided an unprecedented amount of data.

[0003] Programs have extended an array of profiling floats to include biogeochemical sensors for pH, oxygen, nitrate, chlorophyll, suspended particles, and downwelling irradiance. They are intended to address numerous challenges in ocean science and in the management of ocean and global resources. Newly developed sensors allow profiling floats to observe biogeochemical and other properties with sufficient accuracy for climate studies. This data will help determine the seasonal to decadal-scale variability in biological productivity, the supply of essential nutrients from deep waters to the sunlit surface layer, ocean acidification, hypoxia, and ocean uptake of CO2.

[0004] An exemplary cycle of an autonomous profiling float includes receiving mission data for a period of study. The mission data is typically received wirelessly based on communications with satellites. After receiving the mission instructions, the float descends to a target depth in the ocean to drift for a period of time while collecting data. Near the end of the mission, the float may descend, yet more, to gather information from a deeper depth. The float ascends to the ocean surface at the end of the mission, often collecting more profile data along the ascent. Once at the surface, the float may communicate with a receiver to transfer data collected during the mission. In one example, a mission may last for ten or more days at a time. The profiling float is robust and capable of performing many more missions within its lifetime.Docket No.569.0001

[0005] Operational factors, such as mass, reliability, power draw, and maintenance, affect operations of the AUV. Typically, low mass, low power draw, high reliability, and low maintenance are desirable to allow such AUVs to operate as desired. Each component within the AUV contributes to the operational factors of the entire system. Improvements to the operational factors can be beneficial to improve the operational lifetime and usage of the AUV. OVERVIEW

[0006] In accordance with one aspect of the present disclosure, a hydraulic system includes an outer magnetic coupler positioned about an inner magnetic coupler, a motor having a shaft configured to rotate the outer magnetic coupler, and a drive shaft longitudinally movable via rotation of the inner magnetic coupler. A poppet valve is configured to unseat from a sealed state in response to longitudinal movement of the drive shaft. The rotation of the outer magnetic coupler causes rotation of the inner magnetic coupler.

[0007] In accordance with another aspect of the present disclosure, a method for adjusting a buoyancy of an autonomous underwater vehicle (AUV) includes controlling a motor to rotate an outer magnetic coupler positioned about an inner magnetic coupler, the motor comprising a shaft coupled with the outer magnetic coupler. The method also includes causing the inner magnetic coupler to rotate in response to the rotation of the outer magnetic coupler, driving a drive shaft toward a poppet valve in response to the rotation of the inner magnetic coupler, unseating the poppet valve from a seal in response to a movement of the drive shaft, and pumping a hydraulic fluid from an internal reservoir and into an external bladder through the seal, the external bladder positioned externally to a housing of the AUV.

[0008] In accordance with another aspect of the present disclosure, an autonomous underwater vehicle includes a housing, an external bladder coupled to an exterior of the housing, an internal reservoir positioned within an interior volume of the housing, a pump positioned within the interior volume and coupled with the internal reservoir and with the external bladder, and a magnetic coupler assembly. A motor having a shaft is configured to rotate the magnetic coupler assembly, a drive shaft is movable via rotation of the magnetic coupler assembly, and a poppet valve is configured to unseat from a sealed state in response to movement of the drive shaft to allow the pump to transfer a hydraulic fluid from the internal reservoir to the external bladder to increase a buoyancy of the autonomous underwater vehicle.Docket No.569.0001 BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The drawings illustrate embodiments presently contemplated for carrying out the invention.

[0010] In the drawings:

[0011] FIG. 1 is an illustration of an autonomous underwater vehicle according to an embodiment.

[0012] FIG. 2 is a block diagram of a hydarulic system of the AUV of FIG. 1 according to an embodiment.

[0013] FIG. 3 illustrates a valve component of the hydraulic system of FIG. 2 according to an embodiment.

[0014] FIG. 4 illustrates a portion of the valve component of FIG. 3 according to an embodiment.

[0015] FIG.5 illustrates an operational mission for an AUV according to an embodiment.

[0016] FIG. 6 illustrates a flowchart illustrating a method for assigning and carrying out a measurement mission according to an embodiment.

[0017] FIG. 7 illustrates a valve component of the hydraulic system of FIG. 2 according to another embodiment. DETAILED DESCRIPTION

[0018] Embodiments of the present invention provide for an apparatus and method for use in controlling buoyancy in an AUV.

[0019] Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structures. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.

[0020] FIG. 1 illustrates an autonomous underwater vehicle (AUV) 100 according to an embodiment. In one example, the AUV 100 represents an autonomous profiling float such asDocket No.569.0001 the Navis Autonomous Profiling Float available from Sea-Bird Scientific. The AUV 100 includes a sensor head 101, and buoyancy bladders 102, 103 at the bottom. In one embodiment, the buoyancy bladder 102 is an external oil bladder (e.g., extermal oil bladder 202 of FIG. 2) while the buoyancy bladder 103 is an internal air bladder. While at the surface of a body of water such that at least a portion of the AUV 100 is exposed to air, the air buoyancy bladder 103 may be filled via a pneumatic pump 104 to increase the buoyancy of the AUV 100. In addition, the external oil bladder 102 may also be filled to further increase the buoyancy.

[0021] The sensor head 101, for example, includes a satellite antenna 105 for communicating mission parameters, collected measurement data, and the like with a main system (not shown). The sensor head 101 may also include one or more sensors 106 for sensing and detecting conductivity, temperature, pressure, and other parameters of ocean water. Furthermore, an optical dissolved oxygen sensor 107 may be included to assist in critical hypoxia and ocean stoichiometric oxygen chemistry research.

[0022] The Navis buoyancy engine 108 uses a positive displacement piston pump (FIG. 2, 207) to transfer silicon oil from internal to external reservoirs 102, increasing the float volume and causing it to rise. This system provides improved energy efficiency, better parking stability, and an increased depth range compared with existing floats.

[0023] The Navis buoyancy engine 108 is augmented at the sea surface by inflation of an air reservoir 103. This surface-following function provides excess buoyancy to improve surface communications. The open-loop air buoyancy system uses a rubber bladder at the water surface. At the surface, Navis uses a Garmin 15xL-W GPS to acquire positional information. It then transmits the acquired data via an Iridium Transceiver 105. The Iridium antenna is mounted on the end cap 101 and supported by a cell guard.

[0024] FIG.2 illustrates a block diagram of a hydraulic system 200 of the AUV 100 of FIG. 1 according to an embodiment. The hydraulic system 200 includes a chassis or housing 201 having an external oil bladder 202 (e.g., the buoyancy bladder 103 of FIG. 1) coupled thereto that is inflated and deflated using oil from an internal oil bladder reservoir 203 positioned in an interior volume 204 of the housing 201. The amount of oil in the oil bladder 202 external to the interior of the AUV 100 determines a buoyancy of the AUV 100. Increasing the amount of oil in the oil bladder 202 increases the buoyancy, while decreasing the amount of oil decreases the buoyancy. At the surface of the ocean or other body of water, for example, the oil bladderDocket No.569.0001 202 would have an amount of oil sufficient to cause the AUV 100 to float. To sink the AUV 100, the oil in the oil bladder 202 is reduced.

[0025] Increasing the amount of oil in the oil bladder 202 includes activating, via a controller 205 and internal batteries 206, a positive displacement piston pump 207 configured to draw oil from the internal oil bladder reservoir 203 through a low-pressure filter 208 and to force the oil through a high-pressure filter 209 and a check valve 210 of a high-pressure zone 211 of the hydraulic system 200. The external oil bladder 202, fluidly connected to the high-pressure zone 211, fills with oil, which increases the buoyancy of the AUV 100. An advantage of the hydraulic system 200 of the AUV 100 includes maintaining high-pressure within the high- pressure zone 211 without battery energy once the target hydraulic pressure is reached.

[0026] Decreasing the oil in the external oil bladder 202 includes operating, via the controller 205, a regulator 212 connected to a hydraulic valve 213 between the high-pressure zone 211 and the hydraulic valve 213. Oil flowing through the hydraulic valve 213 and the regulator 212 flows without pumping pressure from a pump. Bladder forces of the external oil bladder 202 once high-pressure is released, together with forces from the surrounding water in which the AUV 100 is placed, push the oil from the external oil bladder 202 through the regulator 212, the hydraulic valve 213, and the low-pressure filter 208 back to the internal oil bladder reservoir 203.

[0027] A benefit of the embodiments described herein includes an energy-efficient hydraulic valve 213 that uses efficient battery energy to open a passage through to the low-pressure filter 208 and efficient battery energy to close the passage. Once opened or closed, electrical energy to the hydraulic valve 213 can be removed while the valve maintains its state without further power consumption.

[0028] FIG.3 illustrates a hydraulic valve 300 of the hydraulic system of FIG. 2 according to an embodiment. The hydraulic valve 300 is energy efficient and maintains an open or closed valve state in the absence of electrical energy supplied thereto.

[0029] The hydraulic valve 300 includes an oil input passage 301 fluidly coupled with a poppet chamber 302. The poppet chamber 302 can be sealed from or connected to a plurality of oil output passages 303, 304, 305, 306 formed in a valve body member 307. The oil output passages 303-306 are all fluidly connected to each other. A sealing surface 308 made, for example, from an elastomer, is positioned between the poppet chamber 302 and the oil outputDocket No.569.0001 passage 303. A central opening in the sealing surface 308 allows a poppet 309, assisted by a spring 310, to extend a stem 311 therethrough and to engage an angled poppet sealing surface 312 to seal the oil output passage 303 from the poppet chamber 302. In this manner, oil existing within the oil input passage 301 and the poppet chamber 302 does not flow through to the oil output passage 306 and on to the external oil bladder 202 (FIG. 2). By pressing the stem 311 in a downward direction away from the sealing surface 308, the poppet sealing surface 312 disengages from the sealing surface 308 and allows fluid connectivity between the poppet chamber 302 and the oil output passage 306. In this manner, a higher pressure of the oil in the oil input passage 301 and the poppet chamber 302 allows the oil to flow through the oil output passages 303-306 to be collected in the external oil bladder 202.

[0030] Engaging the stem 311 to allow for oil flow through the hydraulic valve 300 or to seal the oil input passage 301 from the oil output passages 303-306 includes an electromechanical (E / M) system 313. The E / M system 313 involves a gearmotor drive 314 having a motor drive shaft 315 extending into an interior volume of a motor-valve coupler 316. The motor drive shaft 315 engages an outer magnetic coupler 317 having a plurality of outer drive magnets 318 positioned about an outer radius thereof. Electrical control of the gearmotor drive 314 causes the motor drive shaft 315 to rotate, which in turn causes the outer magnetic coupler 317 to rotate in a coupled manner. An iron magnetic shield 319 may be positioned about the outer drive magnets 318 to help maintain their alignment.

[0031] FIG.4 illustrates the motor drive shaft 315 and the outer magnetic coupler 317 of the hydraulic valve 300 according to an embodiment. A paddle 400 is affixed to the end of the motor drive shaft 315 and extends into an opening 401 formed in the outer magnetic coupler 317. Rotation of the motor drive shaft 315 causes the corners of the paddle 400 to engage the sides of the opening 401 thereby rotating the outer magnetic coupler 317 in tandem with the motor drive shaft 315.

[0032] Referring back to FIG. 3, the outer magnetic coupler 317 is positioned around a containment barrier 320 configured to shield a working fluid (e.g., hydraulic oil within the hydraulic system 200) such as that flowing into and out of the external oil bladder 202 described herein. The containment barrier 320 is fixedly attached within the hydraulic valve 300 and does not rotate in response to rotation of the outer magnetic coupler 317. An inner magnetic coupler 321 is positioned near a top of the containment barrier 320 and includes a plurality of inner drive magnets 322 coupled thereto about an outer radius of the inner magnetic coupler 321. InDocket No.569.0001 one embodiment, the inner magnetic coupler 321 is bobbin-shaped and has a threaded internal bore 323 extending longitudinally therethrough. Using the containment barrier as a roller bearing surface for both the inner and outer magnetic couplers allows for significant miniaturization of the valve compared to a design using a standard set of bearings (e.g., such as the design shown in FIG. 5). Miniaturization of the internals of the valve allows one to increase the valve’s maximum depth rating. As the size of internal components increases, the axial force on the containment barrier due to internal hydraulic pressure increases dramatically.

[0033] The placement of the outer magnetic coupler 317 about the containment barrier 320 aligns the outer drive magnets 318 and the inner drive magnets 322 together and creates a magnetic coupling assembly. In one embodiment, the outer magnetic coupler 317 and the inner magnetic coupler 321 are self-aligning with each other due to the magnetic coupling. This self- alignment reduces longitudinal forces exerted on the outer magnetic coupler 317 by the motor drive shaft 315. The rotation of the gearmotor drive 314 that causes the motor drive shaft 315 to rotate the outer magnetic coupler 317 causes rotation of the inner magnetic coupler 321 via magnetic coupling of the outer and inner drive magnets 318, 322. In addition, by magnetically coupling the turning force, the magnetic coupling of the drive allows for the removal of a shaft seal on the drive shaft. Removal of the shaft seal dramatically limits pressure induced loading on the drive shaft and threads. This helps reduce the power needed to actuate the valve and, thus, minimize the overall size of the valve.

[0034] A threaded drive shaft 324 having external threads is engaged with the threads of the bore 323. The threaded drive shaft 324 has an end thereof coupled with a linear actuator 325 positioned within an actuator bore 326 of the valve body member 307. The non-circular shapes of the linear actuator 325 and the actuator bore 326 allow longitudinal movement of the linear actuator 325 within the actuator bore 326 and prevent rotation of the linear actuator 325 within the actuator bore 326. Accordingly, the coupling of the drive shaft end with the linear actuator 325 prevents rotation of the threaded drive shaft 324. In this manner, rotation of the inner magnetic coupler 321 does not cause rotation of the threaded drive shaft 324. By not rotating with the inner magnetic coupler 321, the rotation of the inner magnetic coupler 321 causes the threads of the bore 323 to linearly move the threaded drive shaft 324 up and down within the bore 323. Such linear movement of the threaded drive shaft 324 correspondingly causes like linear movement of the linear actuator 325. The linear actuator 325 engages a push rod 327 at a top end of the rod 327. The push rod 327 is positioned within a central bore 328 of the valveDocket No.569.0001 body member 307 that is, in one embodiment, centrally aligned with the actuator bore 326 and the bore 323 of the containment barrier 320. A bottom end of the push rod 327 engages the stem 311 of the poppet 309 and controls the sealed or open state of the poppet 309.

[0035] In one operational example, electrical energy is provided to the gearmotor drive 314 from the internal battery pack 206 (FIG.2) to cause the motor drive shaft 315 to rotate the outer magnetic coupler 317. The inner magnetic coupler 321, magnetically coupled with the outer magnetic coupler 317, is therefore caused to rotate together with the outer magnetic coupler 317, which causes the threads of the bore 323 to move the threaded drive shaft 324 up or down. In response to a first direction of rotation, the bore threads cause the threaded drive shaft 324 to move toward the poppet 309, which causes the linear actuator 325 to engage the push rod 327 to push the stem 311 downward, which causes the poppet sealing surface 312 to disengage from the sealing surface 308. Accordingly, the oil input passage 301 and the poppet chamber 302 become fluidly coupled with the oil output passages 303-306, and oil is allowed to flow from the external oil bladder 202 to the internal oil bladder reservoir 203 as described herein above. Once moved linearly toward the poppet 309 sufficiently to unseal the input and output chambers, the supply of energy from the battery pack 206 can be removed so that additional energy is not expended from the batteries. However, though energy is removed from the gearmotor drive 314, the position of the threaded drive shaft 324 and, thus, the poppet 309 remains fixed in the open / fluidly coupled position. The poppet 309 remains in the open position until the threaded drive shaft 324 is withdrawn toward the gearmotor drive 314, which allows the spring 310 to move the poppet 309 into the sealed position as described below.

[0036] To seal the oil input passage 301 and the poppet chamber 302 from the oil output passages 303-306 when the poppet 309 is in the unsealed position, electrical energy is provided to the gearmotor drive 314 from the internal battery pack 206 to cause the motor drive shaft 315 to rotate in an opposite direction to cause the inner magnetic coupler 321 to rotate in the opposite direction, thus drawing the threaded drive shaft 324 farther into the bore 323 and away from the direction of the poppet 309. By withdrawing the threaded drive shaft 324 in this manner, the linear actuator 325 correspondingly moves upward, which allows the spring 310 to push the poppet 309 and the push rod 327 in the direction of travel of the threaded drive shaft 324 (e.g., in an upward direction). The spring 310 is allowed to push the poppet 309 into the sealed position. Afterward, energy may be removed from the gearmotor drive 314 to halt further movement of the threaded drive shaft 324. Once sealed, removal of energy from theDocket No.569.0001 gearmotor drive 314 is possible to conserve battery energy while the hydraulic valve 300 remains in the sealed state.

[0037] The hydraulic valve 300 also includes a magnetic detecting system useful to determine when to halt movement of the threaded drive shaft 324. The magnetic detecting system includes a position sense magnet 329 positioned in the linear actuator 325 and a magnetic position sensor 330, such as a Hall effect sensor, positioned to detect a position of the position sensor 330. In one example, the magnetic detecting system is used to signal that the gearmotor drive 314 can be de-energized to halt an operation causing the poppet 309 to unseal. For example, when the linear actuator 325 is positioned to allow the poppet 309 to be in a sealed state, movement of the gearmotor drive 314 may be caused to rotate such that the threaded drive shaft 324 is driven downward to unseal the poppet 309. As the linear actuator 325 is correspondingly driven downward, the push rod 327 eventually becomes aligned with the position sense magnet 329 or to be within a sensing area of the position sense magnet 329 such that the position sense magnet 329 may generate a signal that it senses the push rod 327. In response to sensing the position sense magnet 329, the position of the threaded drive shaft 324 and the linear actuator 325 is understood to have caused the poppet 309 to unseal, and the gearmotor drive 314 may be de-energized. In a like manner, activating the gearmotor drive 314 to withdraw the threaded drive shaft 324 and the linear actuator 325 from the push rod 327 may be halted by de-energizing the gearmotor drive 314 in response to a signal from the position sense magnet 329 that the push rod 327 is no longer sensed. Thus, the hydraulic valve 300 is a latching valve that maintains its sealed or unsealed state after removal of power to the system.

[0038] FIG.5 illustrates an example of an operational mission 500 for an AUV 501 according to an embodiment. FIG. 6 illustrates a flowchart illustrating a method 600 for assigning and carrying out a measurement mission (e.g., the operational mission 500 of FIG.5) according to an embodiment.

[0039] Referring to FIGS.5 and 6, the AUV 501 incorporates the hydraulic system 200 and hydraulic valve 300 described herein. The AUV 501 receives (at step 601) mission parameters for obtaining measurements within the body of water for a period of time. In one embodiment, the AUV 501 may receive the mission data wirelessly (e.g., via the satellite antenna 105) from a satellite 502 communicating with a land-based system (not shown). In another embodiment, the AUV 501 may receive the mission parameters from a ship 503 in the viscinity of the AUV 501. The ship 503 may wirelessly communicate with the AUV 501 using the same protocol asDocket No.569.0001 the communications from the satellite 502, or the ship 503 may take the AUV 501 on board in order to program the mission parameters via a wired or other type of connection. Then, once programmed, the AUV 501 may be placed in the first target depth 504 to begin its mission.

[0040] The mission may include obtaining measurements and other data to allow data analyzation to help determine, for example, the impacts of climate change on biogeochemical distributions and ecosystem dynamics, ocean acidification and carbon cycling, net community production / respiration and changes in community structure, impacts of episodic / anthropogenic events on ecosystems and biogeochemical distributions, phytoplankton bloom dynamics and the resulting flux of carbon, improved ocean biogeochemical and ecosystem models, validation and calibration of ocean color remote sensing data products, and the like. The mission parameters may include instructions detailing one or more target depths at which various measurements are to be taken, the types and kinds of measurements to be takens at or during the one or mre target depths. The parameters may also include the duration of various stages of the mission such as the duration of each measurement, the duration of drifting at each target depth, and so on.

[0041] At step 602, the AUV 501 begins descending to a first target depth 504. While at the surface 505 of the body of water 506, the external oil bladder 102 and the air buoyancy bladder 103 are filled to maintain positioning of the AUV 501 at the surface. To begin the descent, air within the internal air bladder 103 (FIG.1) may be allowed to escape from the AUV 501, which decreases the buoyancy of the AUV 501. Further, the regulator 212 and the hydraulic valve 213 (both of FIG.2) may be allowed to transfer oil in the external oil bladder 202 back to the internal oil bladder reservoir 203 (FIG. 2). A pressure of the water surrounding the AUV 501 may cause the emptying of the external oil bladder 202. As the pressure increases with a greater depth under water, more of the oil within the external oil bladder 202 is forced back into the internal oil bladder reservoir 203. During the descent and during all times while positioned within the body of water 506, the AUV 501 may obtain measurements and other data as detailed by the mission parameters.

[0042] In response to reaching the first target depth of the mission, the buoyancy of the AUV 501 is adjusted (step 603) to maintain the position of the AUV 501 at the first target depth for the duration assigned to the first target depth. The buoyancy adjustment may include operating the pump 207 and check valve 210 to allow an amount of the oil within the internal oil bladder reservoir 203 to flow into the external oil bladder 202. Operating the check valve 210 includes,Docket No.569.0001 in one embodiment, controlling the gearmotor drive 314 to rotate the outer magnetic coupler 317, which causes rotation of the inner magnetic coupler 321 to drive the threaded drive shaft 324 and linear actuator 325 toward the push rod 327 to open the poppet 309. In this manner, oil forced by the pump 207 into the oil input passage 301 is allowed to pass through the oil output passage 306 and into the external oil bladder 202. In response to determining that the amount of oil within the external oil bladder 202 is sufficient to maintain buoyancy of the AUV 501 at the desired depth, the gearmotor drive 314 may control the outer magnetic coupler 317 to rotate in an opposite direction to cause the inner magnetic coupler 321 to move the threaded drive shaft 324 and linear actuator 325 away from the push rod 327, which allows the spring 310 to close the poppet 309. Power to the pump 207 may then be removed to conserve battery energy. The poppet closure maintains a high-pressure sufficient to keep the external oil bladder 202 filled with sufficient oil to maintain the buoyancy at the desired depth. In this manner, little to no energy from the internal batteries 206 is used once the target buoyancy is reached. This allows for the battery energy to be used for the measurements and testing rather than additionally being spent to maintain depth buoyancy. Occasionally, however, minute adjustments to the depth may be warranted in case of buoyancy drift. The volume of oil within the external oil bladder 202 may be adjusted as described above to raise or lower the buoyancy depth of the AUV 501 to maintain the AUV 501 at the appropriate target depth. On such occasions, additional battery energy is used to adjust the buoyancy, but such additional battery energy usage is intermittent to increase battery usage during the mission.

[0043] While drifting at the first target depth 507, measurements are recorded (step 604) per mission parameters. Additional mission-based tests may also be performed. In response to one or more target parameters defining an end to the tasks to be performed at the first target depth, the buoyancy of the AUV 501 may be adjusted (step 605) to move the AUV 501 to a different target depth 508. At the new depth, method 600 may return (606) to step 604 to perform additional measurements and / or tests per the mission parameters. Many depth adjustments may be specified within the mission parameters that allow for many iterations of steps 604-606.

[0044] The mission parameters include, toward the end of the mission, an instruction to return to the surface 505. Accordingly, the AUV 501 ascends 509 to the surface (step 607). During the ascent 509, additional measurements and tests (e.g., salinity and temperature) may be performed. Causing the AUV 501 to ascend includes flooding the external oil bladder 202 with oil from the internal oil bladder reservoir 203 as described herein. Additionally, inDocket No.569.0001 response to being able to fill the buoyancy bladder 103 with air once the surface 505 has been reached, it is filled to assist with maintaining the buoyancy of the AUV 501 at the surface 505.

[0045] At step 608, mission data (e.g., the measurement data and test data acquired during the mission under water) is transmitted to the satellite 502 or to the ship 503 as desired. In addition, wireless transmissions to the ship 503 allow the AUV 501 to be physically located for retrieval.

[0046] FIG.7 illustrates a hydraulic valve 700 of the hydraulic system of FIG. 2 according to an embodiment. The hydraulic valve 700 is energy efficient and maintains an open or closed valve state in the absence of electrical energy supplied thereto.

[0047] The hydraulic valve 700 includes an oil input passage 701 fluidly coupled with a poppet chamber 702. The poppet chamber 702 is sealable from and connectable to a plurality of oil output passages 703, 704, 705, 706 formed in a valve body member 707. The oil output passages 703-706 are all fluidly connected to each other. A sealing surface 708 made, for example, from an elastomer, is positioned between the poppet chamber 702 and the oil output passage 703. A central opening in the sealing surface 708 allows a poppet 709, assisted by a spring 710, to extend a stem 711 therethrough and to engage an angled poppet sealing surface 712 to seal the oil output passage 703 from the poppet chamber 702. In this manner, oil existing within the oil input passage 701 and the poppet chamber 702 does not flow through to the oil output passage 706 and on to the internal oil bladder reservoir 203 (FIG. 2). By pressing the stem 711 in a downward direction away from the sealing surface 708, the poppet sealing surface 712 disengages from the sealing surface 708 and allows fluid connectivity between the oil output passage 703 and the poppet chamber 702. In this manner, a higher pressure of the oil in the oil input passage 701 and the poppet chamber 702 allows the oil to flow through the oil output passages 703-706 to be collected in the internal oil bladder reservoir 203.

[0048] Engaging the stem 711 to allow for oil flow through the hydraulic valve 700 or to seal the oil input passage 701 from the oil output passages 703-706 includes an electrical and mechanical (E / M) system 713. The E / M system 713 includes a gearmotor drive 714 having a motor drive shaft 715 extending into an interior volume of an outer magnetic coupler 716 having a plurality of outer drive magnets 717 positioned about an outer radius thereof. Electrical control of the gearmotor drive 714 causes the motor drive shaft 715 to rotate, which in turn causes the outer magnetic coupler 716 to rotate in a coupled manner. An iron magneticDocket No.569.0001 shield 718 may be positioned about the outer drive magnets 717 to help maintain the outer drive magnets 717 in position.

[0049] The outer magnetic coupler 716 is positioned around a containment barrier 719 configured to shield a working fluid (e.g., hydraulic oil within the hydraulic system 200) such as that flowing into and out of the external oil bladder 202 described herein. The containment barrier 719 is fixedly attached within the hydraulic valve 700 and does not rotate in response to rotation of the outer magnetic coupler 716. An inner magnetic coupler 720 is positioned near a top of the containment barrier 719 and includes a plurality of inner drive magnets 721 coupled thereto about an outer radius of the inner magnetic coupler 720.

[0050] The placement of the outer magnetic coupler 716 about the containment barrier 719 aligns the outer drive magnets 717 and the inner drive magnets 721 together. In one embodiment, the outer magnetic coupler 716 and the inner magnetic coupler 720 are self- aligning with each other due to the magnetic coupling. This self-alignment reduces longitudinal forces exerted on the outer magnetic coupler 716 by the motor drive shaft 715. The rotation of the gearmotor drive 714 that causes the motor drive shaft 715 to rotate the outer magnetic coupler 716 causes rotation of the inner magnetic coupler 720 via magnetic coupling of the outer and inner drive magnets 717, 721. In addition, by magnetically coupling the turning force, the magnetic coupling of the drive allows for the removal of a shaft seal on the drive shaft. Removal of the shaft seal dramatically limits pressure induced loading on the drive shaft and threads. This helps reduce the power needed to actuate the valve and, thus, minimize the overall size of the valve.

[0051] The inner magnetic coupler 720 is coupled to a threaded drive shaft 722 (e.g., an acme screw driveshaft) having external threads configured to engage with the threads of a linear actuator 723 (e.g., an acme screw drive) with a bore 724 of the linear actuator 723. The threaded drive shaft 722 has an end thereof coupled with the inner magnetic coupler 720 such that the inner magnetic coupler 720 and the threaded drive shaft 722 rotate together. A bearing assembly 725 helps maintain alignment of the threaded drive shaft 722 with the linear actuator 723 and supports the rotation of the threaded drive shaft 722. The linear actuator 723 is positioned within a bore 726 of the valve body member 707. The non-circular shapes of the linear actuator 723 and the actuator bore 726 allow longitudinal movement of the linear actuator 723 within the actuator bore 726 and prevent rotation of the linear actuator 723 within the actuator bore 726. Accordingly, the coupling of the drive shaft end with the inner magneticDocket No.569.0001 coupler 720 provides rotation of the threaded drive shaft 722 while the linear actuator 723 is prevented from rotating. In this manner, rotation of the inner magnetic coupler 720 causes the threads of the threaded drive shaft 722 to linearly move the linear actuator 723 up and down within the actuator bore 726. The linear actuator 723 engages a push rod 727 at a top end of the rod 727. The push rod 727 is positioned within a central bore 728 of the valve body member 707 that is, in one embodiment, centrally aligned with the actuator bore 726. A bottom end of the push rod 727 engages the stem 711 of the poppet 709 and controls the sealed or open state of the poppet 709.

[0052] Operation of the hydraulic valve 700 is similar to the operation described above for the hydraulic valve 300. The hydraulic valve 700 also includes a magnetic detecting system useful to determine when to halt movement of the threaded drive shaft 722. The magnetic detecting system includes a position sense magnet 729 positioned in the linear actuator 723 and a magnetic position sensor 730, such as a Hall effect sensor, positioned to detect a position of the position sensor 730. In one example, the magnetic detecting system is used to signal that the gearmotor drive 714 can be de-energized to halt an operation causing the poppet 709 to seal or unseal.

[0053] The hydraulic system valve disclosed herein improves existing designs by reducing mass while maintaining the ability to work with system working pressures up to 14000 PSI. In some embodiments, the valve is sufficient to work up to 8000 PSI or 4000 PSI. The pressure compensation of the valve drive shaft allows the design to be easily scaled up or down to meet various system max pressure ratings. In one embodiment, the mass of the system is less than 400 g and may be less than 200 g. Further, the disclosed valve system is configured to operate with drive currents, for example, in the range of 0.02 amps for lower pressure systems (e.g., 4000 PSI) and typically less than 0.1 amps for higher pressure systems (e.g., > 4000 PSI). Embodiments of this disclosure allow for a miniaturization of a high-pressure hydraulic valve. The valve assembly is designed to be a module that threads into a hydraulic manifold to reduce mass and internal seal count. The disclosed containment barrier functions as a roller bearing surface for the bobbin as well. Making the inner magnet coupler (e.g., the bobbin) into a roller bearing also allows magnets to be closer together and increases magnetic coupling force.

[0054] While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any numberDocket No.569.0001 of variations, alterations, substitutions, or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the present disclosure. Additionally, while various embodiments of the present disclosure have been described, it is to be understood that aspects of the present disclosure may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description but is only limited by the scope of the appended claims.

Claims

Docket No.569.0001 CLAIMS What is claimed is:

1. A hydraulic system comprising: an outer magnetic coupler positioned about an inner magnetic coupler; a motor having a shaft configured to rotate the outer magnetic coupler; a drive shaft longitudinally movable via rotation of the inner magnetic coupler; and a poppet valve configured to unseat from a sealed state in response to longitudinal movement of the drive shaft; wherein rotation of the outer magnetic coupler causes rotation of the inner magnetic coupler.

2. The hydraulic system of claim 1 further comprising: a linear actuator coupled with the drive shaft; and a push rod positioned between the linear actuator and the poppet valve; wherein, in response to a longitudinal movement of the drive shaft in a first direction, the linear actuator engages the push rod to unseat the poppet valve from the sealed state.

3. The hydraulic system of claim 2 further comprising a valve body member having a non- circular bore formed therein; wherein the linear actuator is longitudinally movable within the non-circular bore.

4. The hydraulic system of claim 1, wherein the drive shaft comprises external threads; wherein the inner magnetic coupler has a bore longitudinally formed therein; and wherein the inner magnetic coupler comprises internal threads formed in the bore and configured to engage the external threads during the rotation of the inner magnetic coupler.

5. The hydraulic system of claim 1, wherein the outer magnetic coupler comprises a plurality of outer drive magnets coupled about a radius of the outer magnetic coupler; andDocket No.569.0001 wherein the inner magnetic coupler comprises a plurality of inner drive magnets coupled about a radius of the inner magnetic coupler.

6. The hydraulic system of claim 5, wherein the outer magnetic coupler is self-aligned with the inner magnetic coupler based on a magnetic coupling of the plurality of outer and inner drive magnets.

7. The hydraulic system of claim 1 further comprising: a chassis; an external bladder coupled to an exterior of the chassis; an internal reservoir positioned within an interior volume of the chassis; and a pump positioned within the interior volume and coupled with the internal reservoir and with the external bladder.

8. The hydraulic system of claim 7 further comprising a controller; wherein the controller is configured to activate the pump to cause a hydraulic fluid to transfer from the internal reservoir to the external bladder to increase a buoyancy of the hydraulic system.

9. The hydraulic system of claim 8 further comprising a regulator coupled with the external bladder; wherein the controller is further configured to activate the regulator to allow the hydraulic fluid within the external bladder to transfer to the internal reservoir.

10. A method for adjusting a buoyancy of an autonomous underwater vehicle (AUV) comprising: controlling a motor to rotate an outer magnetic coupler positioned about an inner magnetic coupler, the motor comprising a shaft coupled with the outer magnetic coupler; causing the inner magnetic coupler to rotate in response to the rotation of the outer magnetic coupler;Docket No.569.0001 driving a drive shaft toward a poppet valve in response to the rotation of the inner magnetic coupler; unseating the poppet valve from a seal in response to a movement of the drive shaft; and pumping a hydraulic fluid from an internal reservoir and into an external bladder through the seal, the external bladder positioned externally to a housing of the AUV.

11. The method of claim 10, wherein controlling the motor comprises controlling the motor to rotate the outer magnetic coupler in a first rotational direction; and wherein the method further comprises: controlling the motor to rotate the outer magnetic coupler in a second rotational direction opposite the first rotational direction; driving the drive shaft away from the poppet valve in response to the rotation of the outer magnetic coupler in the second rotational direction; and seating the poppet valve against the seal in response to driving the drive shaft away from the poppet valve.

12. The method of claim 11, further comprising disengaging electrical energy from the motor in response to the seating of the poppet valve; wherein an amount of the hydraulic fluid pumped into the external bladder remains constant in response to the disengaging of the electrical energy from the motor.

13. The method of claim 11, wherein the drive shaft is threadedly engaged with the inner magnetic coupler; and wherein driving the drive shaft toward the poppet valve comprises longitudinally driving a linear actuator fixedly engaged with the drive shaft toward the poppet valve via the rotation of the inner magnetic coupler.

14. The method of claim 10, wherein a buoyancy of the UAV increases in response to the pumping of the hydraulic fluid from the internal reservoir into the external bladder.Docket No.569.0001 15. The method of claim 14 further comprising controlling a regulator to allow the hydraulic fluid within the internal reservoir to return to the internal reservoir.

16. An autonomous underwater vehicle comprising: a housing; an external bladder coupled to an exterior of the housing; an internal reservoir positioned within an interior volume of the housing; a pump positioned within the interior volume and coupled with the internal reservoir and with the external bladder; a magnetic coupler assembly; a motor having a shaft configured to rotate the magnetic coupler assembly; a drive shaft movable via rotation of the magnetic coupler assembly; and a poppet valve configured to unseat from a sealed state in response to movement of the drive shaft to allow the pump to transfer a hydraulic fluid from the internal reservoir to the external bladder to increase a buoyancy of the autonomous underwater vehicle.

17. The autonomous underwater vehicle of claim 16, wherein the magnetic coupler assembly comprises: an inner coupler; and an outer coupler positioned about the inner coupler and magnetically coupled with the inner coupler, wherein rotation of the outer coupler causes rotation of the inner coupler.

18. The autonomous underwater vehicle of claim 17 further comprising: a linear actuator fixedly coupled with the drive shaft; and a push rod positioned between the linear actuator and the poppet valve; wherein the drive shaft is threadedly coupled with the inner coupler; and wherein, in response to a rotational movement of the inner coupler, the drive shaft is caused to move longitudinally in a first direction to engage the push rod to unseat the poppet valve from the sealed state.Docket No.569.0001 19. The autonomous underwater vehicle of claim 17 further comprising: a linear actuator threadedly coupled with the drive shaft; and a push rod positioned between the linear actuator and the poppet valve; wherein the drive shaft is fixedly coupled with the inner coupler; and wherein, in response to a rotational movement of the inner coupler and the drive shaft, the linear actuator is caused to move longitudinally in a first direction to engage the push rod to unseat the poppet valve from the sealed state.

20. The autonomous underwater vehicle of claim 17, wherein the outer coupler comprises a plurality of outer drive magnets coupled about a radius of the outer coupler; and wherein the inner coupler comprises a plurality of inner drive magnets coupled about a radius of the inner coupler.

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