Rapid buoyancy adjusting system for underwater glider

Abstract

The invention discloses a quick buoyancy adjusting system for an underwater glider, which belongs to the technical field of underwater detection equipment, comprises a pressure-resistant shell and an outer leather bag arranged on the outer side of the pressure-resistant shell, and is characterized by comprising an energy accumulator, an oil return control valve, an oil discharge control valve, a hydraulic pump and a motor for driving the hydraulic pump, the energy accumulator is arranged on the inner side of the pressure-resistant shell and communicated with the outer leather bag through a first pipeline and a second pipeline which are connected in parallel, the hydraulic pump and the oil return control valve are installed on the first pipeline in series, and the oil discharge control valve is installed on the second pipeline in series. The initial pressure of the energy accumulator is larger than the hydrostatic pressure of the target working water depth position of the underwater glider. The system is simple in structural form and novel in working principle, the buoyancy adjusting speed of an existing underwater glider can be greatly increased, the rapid floating-diving conversion capacity in the complex marine environment is formed, and the system serves application scenes such as under-ice observation and rapid profile observation of the underwater glider.

Description

Technical Field

[0001] The present invention belongs to the technical field of underwater detection equipment, and particularly relates to a rapid buoyancy adjustment system for an underwater glider. Background Art

[0002] An underwater glider is a new type of unmanned autonomous underwater vehicle. It changes its buoyancy through a buoyancy adjustment system to complete the floating-diving state conversion, and realizes a "zigzag" motion trajectory by the cooperation of attitude adjustment and hydrodynamic forces acting on the wings. The underwater glider has the advantages of low power consumption, long endurance, and low noise. It can be integrated with various ocean sensors to serve scientific research such as wide-area continuous refined observation and detection of the ocean.

[0003] For the buoyancy adjustment method of an underwater glider, usually when surfacing and diving, a hydraulic pump or the negative pressure inside the pressure-resistant shell is used to input the working medium from an external bladder or seawater into the internal cavity fuel tank, reducing the drainage volume of the underwater glider to achieve the purpose of reducing buoyancy; when diving and surfacing, a hydraulic pump is used to transport the working medium in the internal cavity fuel tank to the external bladder or seawater, increasing the drainage volume of the underwater glider to achieve the purpose of increasing buoyancy.

[0004] For the existing buoyancy adjustment method of an underwater glider, the speed of changing the drainage volume during the floating-diving state conversion stage is limited, resulting in an increase in the state conversion time on the water surface and underwater, which restricts the improvement of the mobility and rapidity of the underwater glider. During the surfacing-to-diving stage, the long waiting time on the water surface will increase the probability of the underwater glider being collided by surface vessels and fouled by surface organisms; during the diving-to-surfacing stage, the slow oil drainage speed restricts the buoyancy adjustment speed, which will cause the problem of over-depth when the underwater glider dives to the target depth. Moreover, after diving and surfacing, the too long non-steady state conversion time will reduce the data sampling quality in this stage.

[0005] In the observation tasks of strong ocean dynamic processes such as mesoscale eddies and Kuroshio extensions, the limited oil drainage speed of the traditional buoyancy adjustment system makes the floating-diving conversion of the underwater glider slow. The too long water surface residence time will cause too large a deviation in the water surface drifting position, reducing the target trajectory keeping ability. For the observation tasks in strong current sea areas, the underwater glider must have a faster floating-diving conversion speed in order to shorten the time of the floating-diving conversion stage on the water surface and underwater and improve the working state conversion response ability of the underwater glider. Therefore, designing a rapid buoyancy adjustment system for an underwater glider is of great significance for improving the floating-diving conversion speed of the underwater glider and shortening the over-depth distance of the target depth. In the future, it can also be applied to underwater gliders under ice, providing key technical support for the rapid floating-diving conversion near the ice surface and reducing the risk of collision between the underwater glider under ice and the ice cover or broken ice. Summary of the Invention

[0006] In view of the technical problems of slow oil return speed during the buoyancy adjustment of existing underwater gliders, lag in the response of the floating-diving state conversion, resulting in long conversion time, inaccurate target depth control, and poor trajectory keeping ability, the present invention provides a rapid buoyancy adjustment system for underwater gliders.

[0007] The present invention is implemented as follows. A rapid buoyancy adjustment system for an underwater glider includes a pressure-resistant housing and an outer skin bag provided outside the pressure-resistant housing. It is characterized in that: it includes an accumulator, an oil return control valve, an oil discharge control valve, a hydraulic pump, and a motor for driving the hydraulic pump. The accumulator is arranged inside the pressure-resistant housing. The accumulator is communicated with the outer skin bag through a first pipeline and a second pipeline connected in parallel. The hydraulic pump and the oil return control valve are serially installed in the first pipeline, and the oil discharge control valve is serially installed in the second pipeline. The initial pressure of the accumulator is greater than the hydrostatic pressure at the target working water depth position of the underwater glider.

[0008] In the above technical solution, preferably, the oil return control valve is a check valve, and the check valve prevents the working medium in the accumulator from flowing into the outer skin bag; the oil discharge control valve is a globe valve, and the globe valve controls the on-off of the second pipeline.

[0009] In the above technical solution, preferably, the hydraulic pump is arranged between the outer skin bag and the check valve.

[0010] In the above technical solution, preferably, a filter serially installed in the first pipeline is arranged between the hydraulic pump and the outer skin bag.

[0011] In the above technical solution, preferably, the hydraulic pump, the motor, the filter, the oil return control valve, and the oil discharge control valve are installed in the pressure-resistant housing.

[0012] According to the theory of orifice flow, for oil supply units such as hydraulic pumps and accumulators, when the physical flow conditions do not change, the flow rate of the oil supply unit is proportional to the first power of the pressure difference before and after the throttle orifice. Based on this principle, the technical solution of the present invention has the following technical effects: 1. Compared with the oil return method of the surface negative pressure oil tank in the existing buoyancy adjustment system of underwater gliders, the present invention removes the inner oil tank of the existing buoyancy adjustment system. During the oil return process on the water surface, the hydraulic pump overcomes the initial pressure of the accumulator and actively transports the working medium into the accumulator to store energy using the accumulator. During this process, the pressure difference before and after the throttle orifice of the hydraulic pump is significantly higher than the pressure difference of the negative pressure oil tank in the original buoyancy system, which can effectively increase the oil return speed.

[0013] 2. Compared with the existing underwater glider buoyancy adjustment system that uses a hydraulic pump to drain oil underwater, the present invention utilizes the pressure difference between the high pressure of the accumulator after energy storage on the water surface and the seawater pressure where the outer bladder is located to transport the oil in the accumulator to the outer bladder. During this process, the pressure difference across the throttle orifice of the accumulator is significantly higher than the pressure difference formed by the oil-draining hydraulic pump of the original buoyancy system, which can significantly increase the oil-draining speed.

[0014] 3. After the fast buoyancy adjustment system is integrated into the underwater glider, by controlling the opening and closing of the hydraulic pump and the oil-draining control valve, the oil-returning and oil-draining actions of the underwater glider at any water depth position can be achieved, providing technical support for segmented oil-returning and oil-draining.

[0015] In summary, the fast buoyancy adjustment system for underwater gliders proposed by the present invention has a simple structural form and a novel working principle, which can significantly increase the buoyancy adjustment speed of existing underwater gliders, form the ability of rapid floating-diving conversion in complex marine environments, and serve application scenarios such as sub-ice observation and rapid profile observation of underwater gliders. Brief Description of the Drawings

[0016] Figure 1 It is a schematic structural diagram of an embodiment of the fast buoyancy adjustment system for underwater gliders of the present invention; Figure 2 It is a flow chart of the working medium when an embodiment of the fast buoyancy adjustment system for underwater gliders of the present invention is in the water surface oil-return working mode; Figure 3 It is a flow chart of the working medium when an embodiment of the fast buoyancy adjustment system for underwater gliders of the present invention is in the underwater oil-draining working mode. Detailed Description of the Embodiment

[0017] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0018] To solve the technical problems such as slow oil-returning and oil-draining speeds, lagging response in floating-diving state conversion, long conversion time, inaccurate target depth control, and poor trajectory-holding ability during the buoyancy adjustment of existing underwater gliders, the present invention specifically provides a fast buoyancy adjustment system for underwater gliders. To further illustrate the structure of the present invention, it is described in detail below in conjunction with the drawings: Please refer to Figure 1 and Figure 2, A rapid buoyancy adjustment system for an underwater glider, comprising a pressure-resistant housing 8, and an outer bladder 1 is installed outside the pressure-resistant housing 8. A filter 2, a hydraulic pump 3, a drive motor 5, an oil return control valve 4, an oil discharge control valve 6, an accumulator 7, a first pipeline and a second pipeline are installed inside the pressure-resistant housing 8. The accumulator is communicated with the outer bladder through the parallel first pipeline and second pipeline. The hydraulic pump and the oil return control valve are serially installed in the first pipeline, and the oil discharge control valve is serially installed in the second pipeline. The initial pressure of the accumulator is greater than the hydrostatic pressure at the target working water depth position of the underwater glider. Specifically, the oil return control valve is a one-way valve, and the stop valve prevents the working medium in the accumulator from flowing to the outer bladder; the oil discharge control valve is a stop valve, and the stop valve controls the on-off of the second pipeline. The hydraulic pump is arranged between the outer bladder and the one-way valve. The filter is arranged between the hydraulic pump and the outer bladder. The stop valve is a solenoid valve.

[0019] In this embodiment, hydraulic oil is selected as the working medium of the buoyancy drive system for description. When the buoyancy needs to be reduced, the process of transporting the working medium from the outer bladder to the accumulator is the energy storage process, simply referred to as "oil return"; when the buoyancy needs to be increased, the process of transporting the working medium from the accumulator to the outer bladder is the energy release process, simply referred to as "oil discharge".

[0020] In this embodiment, the outer bladder, the filter, the hydraulic pump, the one-way valve, the accumulator and the first pipeline form an oil return oil circuit for performing the oil return process to reduce the drainage volume and buoyancy; the outer bladder, the solenoid valve, the accumulator and the second pipeline form an oil discharge oil circuit for performing the oil discharge process to increase the drainage volume and buoyancy.

[0021] In this embodiment, based on the basic principle of buoyancy adjustment in this embodiment and combined with the internal space size of the pressure-resistant housing, various position layout cases can be designed for the spatial layout and installation relative relationship of the key components of the buoyancy adjustment system.

[0022] Specifically, in the embodiment, for the oil return process of the buoyancy adjustment system, please refer to Figure 2 , for the oil discharge process, please refer to Figure 3 .

[0023] Specifically, when the underwater glider needs to reduce the buoyancy, the oil return action is performed through the first pipeline. Please refer to Figure 2 . In the embodiment, the solenoid valve is in a normally closed state. The control system sends an instruction to the driver of the motor to start the motor to drive the hydraulic pump to open, and quickly transports the working medium in the outer bladder along the first pipeline to the accumulator, reducing the drainage volume of the underwater glider and achieving the adjustment purpose of reducing the buoyancy.

[0024] In an embodiment, the working medium flowing through the filter can filter impurities in the working medium, ensuring the cleanliness of the working medium at the inlet of the hydraulic pump. The check valve only allows the working medium to flow from the outlet of the hydraulic pump to the inlet of the accumulator, blocking reverse flow. During the oil return process, the hydraulic pump needs to do work against the pressure difference between the accumulator and the outer bladder, transporting the working medium into the accumulator. This process increases the pressure of the working medium in the accumulator, making its pressure greater than the hydrostatic pressure at the target working depth of the underwater glider, storing the differential pressure energy for driving during the underwater oil discharge process.

[0025] Specifically, when the underwater glider needs to increase buoyancy, an oil discharge action is performed through the second pipeline. Please refer to Figure 3 . In the embodiment, the check valve can block the working medium in the accumulator from flowing back to the outer bladder along the first pipeline. At this time, the solenoid valve is opened. Since the pressure of the working medium in the accumulator is greater than the hydrostatic pressure at the water depth where the outer bladder of the underwater glider is located, under the drive of the pressure difference, the working medium in the accumulator quickly transports along the second pipeline through the solenoid valve to the outer bladder, increasing the drainage volume of the underwater glider and achieving the adjustment purpose of increasing buoyancy.

[0026] In the embodiment, it is required that the pressure value in the accumulator is not less than the hydrostatic pressure value at the target water depth of the underwater glider after the oil discharge is completed, so as to ensure that a rapid oil discharge action is performed at the target water depth, increasing the drainage volume and buoyancy and achieving the goal of rapid buoyancy adjustment.

[0027] In the embodiment, if the accumulator with an initial pressure has the ability to withstand external pressure, the accumulator can be placed outside the pressure-resistant housing in contact with the external environment and connected to the components inside the pressure-resistant housing through a pressure-resistant pipeline, which can save the internal space of the pressure-resistant housing for arranging other devices that cannot withstand pressure; if a working medium with high cleanliness or a low requirement for the cleanliness of the working medium by the hydraulic pump is selected, the filter can be removed.

[0028] In the embodiment, the basic principle of the rapid buoyancy adjustment system for the underwater glider is mainly introduced, and an implementation method is given, without detailing the selection of specific hydraulic components, the installation and connection methods of components, the design of the control system, etc.

[0029] The operation of this rapid buoyancy adjustment system for the underwater glider can be divided into two stages: oil return and oil discharge: Surface oil return stage: The components in the oil return pipeline start to work, and the underwater glider transfers from the waiting state on the water surface to the oil return and diving state. The motor and the hydraulic pump are started, and the working medium in the outer bladder is quickly transported to the accumulator along the filter and the check valve. The drainage volume of the underwater glider decreases, realizing diving. During this process, the hydraulic pump needs to do work against the difference between the atmospheric pressure and the initial pressure value of the accumulator. After the oil return is completed, the pressure of the accumulator will exceed the hydrostatic pressure at the target working depth of the underwater glider.

[0030] Underwater oil drainage stage: Before the underwater glider reaches the target depth, the components in the oil drainage pipeline start to work. The underwater glider decelerates from the diving state and then turns into the floating state as the buoyancy increases. Open the solenoid valve. Since the pressure of the accumulator is greater than the hydrostatic pressure of the seawater on the outer bladder, under the drive of the pressure difference, the working medium in the accumulator is quickly transported along the solenoid valve to the outer bladder, and the drainage volume of the underwater glider increases, realizing floating.

[0031] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A rapid buoyancy adjustment system for an underwater glider, comprising a pressure-resistant housing and an outer skin bladder provided outside the pressure-resistant housing, characterized in that: It includes an accumulator, an oil return control valve, an oil discharge control valve, a hydraulic pump and a motor for driving the hydraulic pump. The accumulator is arranged inside the pressure-resistant housing. The accumulator is communicated with the outer bladder through a first pipeline and a second pipeline connected in parallel. The hydraulic pump and the oil return control valve are serially installed in the first pipeline, and the oil discharge control valve is serially installed in the second pipeline. The initial pressure of the accumulator is greater than the hydrostatic pressure at the target working water depth position of the underwater glider.

2. The rapid buoyancy adjustment system for an underwater glider according to claim 1, characterized in that: The oil return control valve is a check valve, and the check valve prevents the working medium in the accumulator from flowing into the outer bladder; the oil discharge control valve is a globe valve, and the globe valve controls the on-off of the second pipeline.

3. The rapid buoyancy adjustment system for an underwater glider according to claim 2, characterized in that: The hydraulic pump is arranged between the outer bladder and the check valve.

4. The rapid buoyancy adjustment system for an underwater glider according to claim 3, characterized in that: A filter serially installed in the first pipeline is arranged between the hydraulic pump and the outer bladder.

5. The rapid buoyancy adjustment system for an underwater glider according to claim 4, characterized in that: The hydraulic pump, the motor, the filter, the oil return control valve and the oil discharge control valve are installed in the pressure-resistant housing.

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