Test support device mass trim drive system, method, and flow field test system

Abstract

The application provides a test support device quality trimming driving system, method and flow field test system, which comprises an oil supply main pipe, two oil supply branch pipes and an oil return main pipe; each oil supply branch pipe is connected to the oil supply main pipe through a first stop valve, and a second accumulator is connected to each oil supply branch pipe; the outlets of the two oil supply branch pipes are respectively communicated with two oil chambers of a hydraulic cylinder; an overflow valve is connected to one of the oil supply branch pipes, the overflow valve is connected to the oil return main pipe through a first oil return branch pipe, the other oil supply branch pipe is connected to the oil return main pipe through a second oil return branch pipe, and a second stop valve is arranged on the second oil return branch pipe. The quality of a test model support component can be trimmed in the sinking and floating movement process of the flow field test, and the quality of the test model support component does not affect the model test. Moreover, the frequency of the trimming movement can be realized by adjusting the pressure of the balancing accumulator, i.e. adjusting the pressure of the second accumulator, so that the wideband quality trimming from low frequency to high frequency can be realized.

Description

Technical Field

[0001] This invention relates to the field of flow field testing technology, and in particular to a test support device mass balancing drive system, method, and flow field testing system. Background Technology

[0002] Flow field testing is a crucial experimental method in fluid mechanics, primarily used to study the dynamic characteristics of objects in fluid flow. Flow field testing involves placing a model of an object in a flow field and artificially creating fluid flow to study the fluid flow and its interaction with the model. Flow field testing involves heave motion; typically, the test specimen is raised to a neutral position using test model support components before the experiment. Actual experiments have shown that the mass of the test model support components has a significant impact on the flow field motion of the test specimen. Summary of the Invention

[0003] In view of the above problems, the present invention is proposed to provide a test support device mass balancing drive system, method and flow field test system that overcomes or at least partially solves the above problems, and can realize the balancing of the mass of the test model support component during the heave motion of the flow field test, so that the mass of the test model support component does not affect the model test.

[0004] Specifically, the present invention provides a test support device mass balancing drive system, which includes an oil supply main pipe, two oil supply branch pipes and a return oil main pipe;

[0005] A first accumulator is connected to the main oil pipeline;

[0006] Each of the oil delivery branches is connected to the main oil delivery branch via a first shut-off valve, and each oil delivery branch is connected to a second accumulator; the outlets of the two oil delivery branches are respectively connected to the two oil chambers of the hydraulic cylinder; wherein...

[0007] One of the oil supply branches is connected to an overflow valve, which is connected to the main oil return branch through a first return branch. Another oil supply branch is connected to the main oil return branch through a second return branch, and a second shut-off valve is provided on the second return branch. Alternatively, each of the oil supply branches is connected to an overflow valve, and each overflow valve is connected to the main oil return branch through a return branch.

[0008] Optionally, each of the oil delivery branches is provided with a hydraulic lock, the second accumulator is connected to the section of the oil delivery branch located between the hydraulic lock and the first shut-off valve, and the corresponding overflow valve is connected to the section of the oil delivery branch located between the hydraulic lock and the first shut-off valve.

[0009] Optionally, a pressure reducing valve is provided on the section of the main oil pipeline between the connection point of the first accumulator and the first shut-off valve, and the pressure reducing valve is also connected to the return oil pipeline.

[0010] A safety valve is connected to the section of the oil supply branch pipe located between the hydraulic lock and the oil chamber, and the safety valve is connected to the return oil main pipe.

[0011] Optionally, a first pressure sensor is connected to the section of the main oil pipeline between the pressure reducing valve and the first shut-off valve;

[0012] A second pressure sensor is connected to the oil delivery branch pipe connected to the overflow valve, on the pipeline between the connection point of the first shut-off valve and the overflow valve;

[0013] A third pressure sensor is connected to the section of the oil delivery pipe located between the safety valve and the oil chamber.

[0014] Optionally, it also includes a hydraulic lock control valve, which is connected to the main oil supply pipe, the hydraulic lock, and the main oil return pipe via a pipeline.

[0015] Optionally, it also includes a guide rail clamp and a clamp control valve; the clamp control valve is connected to the oil supply main, the guide rail clamp, and the oil return main via a pipeline.

[0016] The present invention also provides a flow field testing system, including a flow field, a hydraulic cylinder, a heave motion guide rail, and a test model support component, as well as a mass balancing drive system for any of the above-mentioned test support devices; the test model support component is movably mounted on the heave motion guide rail, the output rod of the hydraulic cylinder is vertically arranged, and the output rod is connected to the test model support component; the outlets of the two oil delivery pipes are respectively connected to the two oil chambers of the hydraulic cylinder.

[0017] Optionally, there are two hydraulic cylinders, respectively disposed on both sides of the test model support component; the lower end of the cylinder body of the hydraulic cylinder is universally connected to the fixed base; the upper end of the output rod is universally connected to the test model support component.

[0018] The test model support component is provided with an upper limit buffer on the upper side and a lower limit buffer on the lower side.

[0019] The present invention also provides a mass balancing method using any of the above-mentioned test support device mass balancing drive systems, comprising:

[0020] Adjust the charging pressure of the two second accumulators;

[0021] Hydraulic oil is first charged into one of the second accumulators in a preset sequence, and then hydraulic oil is charged into the other second accumulator.

[0022] The hydraulic oil is input to control the output rod of the hydraulic cylinder to move upward, and the speed at which the output rod moves upward is also controlled.

[0023] The overflow valve is controlled to adjust the pressure difference between the two second accumulators;

[0024] Conduct flow field tests.

[0025] In the test support device mass balancing drive system, method, and flow field test system of the present invention, because it has two second accumulators and two hydraulic cylinders, the two hydraulic cylinders support the test model support component, and the pressure difference between the two second accumulators can balance the mass of the test model support component, so that the test piece installed on the test model support component is not affected by the test model support component during the flow field test. That is, the test support device mass balancing drive system can achieve mass balancing of the test model support component during the heave motion process of the flow field test, and the mass of the test model support component does not affect the model test. Furthermore, the frequency of the balancing motion can be adjusted by adjusting the pressure of the balancing accumulator, i.e., adjusting the pressure of the second accumulator, thus achieving broadband mass balancing from low frequency to high frequency.

[0026] The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0027] The following sections will describe some specific embodiments of the invention in detail by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0028] Figure 1 This is a schematic structural diagram of a test support device mass balancing drive system according to an embodiment of the present invention;

[0029] Figure 2 This is a schematic structural diagram of a flow field test system according to an embodiment of the present invention. Detailed Implementation

[0030] The following reference Figures 1 to 2This description covers the mass balancing drive system, method, and flow field test system for the test support device according to embodiments of the present invention. In this description, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature, that is, include one or more of that feature. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified. When a feature "includes or contains" one or more of the features it encompasses, unless otherwise specifically described, this indicates that other features are not excluded and may be further included.

[0031] Unless otherwise expressly specified and limited, the terms "set up," "install," "connect," "link," "fix," and "couple" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art should be able to understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0032] Furthermore, in the description of this embodiment, "above" or "below" the second feature can include direct contact between the first and second features, or it can include contact between the first and second features through another feature between them. That is, in the description of this embodiment, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," or "below" of the second feature can mean the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0033] In the description of this embodiment, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0034] Figure 1This is a schematic structural diagram of a test support device mass balancing drive system according to an embodiment of the present invention, such as... Figure 1 As shown, and with reference Figure 2 This invention provides a test support device mass balancing drive system 100, including a main oil supply pipe 21, two branch oil supply pipes 22, and a return oil main pipe 23. A first accumulator 24, a pressure-stabilizing accumulator, is connected to the main oil supply pipe 21 to stabilize the external oil source pressure. Each branch oil supply pipe 22 is connected to the main oil supply pipe 21 via a first shut-off valve, and a second accumulator, referred to as a balancing accumulator, is connected to each branch oil supply pipe 22. The outlets of the two branch oil supply pipes are respectively connected to the two oil chambers of a hydraulic cylinder 40. One branch oil supply pipe 22 is connected to an overflow valve 35, which is connected to the return oil main pipe 23 via a first return oil branch pipe. The other branch oil supply pipe 22 is connected to the return oil main pipe 23 via a second return oil branch pipe, and a second shut-off valve 36 is installed on the second return oil branch pipe.

[0035] In this embodiment of the invention, the test support device mass balancing drive system 100, during operation, charges two second accumulators with air, adjusting the pressure of the second accumulators to adapt to the frequency of the corresponding flow field test. Then, it closes two first shut-off valves, supplying hydraulic oil to the first accumulator 24. After the pressure in the first accumulator 24 reaches a preset value, it controls one of the first shut-off valves to open. The oil chamber corresponding to this first shut-off valve is the rod chamber 42 of the hydraulic cylinder 40, allowing the corresponding second accumulator to receive hydraulic oil. After the pressure in this second accumulator reaches a preset value, it closes the first shut-off valve and opens the other first shut-off valve, allowing the corresponding second accumulator to receive hydraulic oil. After the pressure in this second accumulator reaches a preset value, it continues to charge hydraulic oil, causing the output rods 41 of the two hydraulic cylinders 40 to move upward, driving the test model support component 60 to move to a preset position. After the test model support component 60 moves to the preset position, the pressure of the corresponding second accumulator is adjusted by the relief valve 35, so that the pressure difference between the two second accumulators is balanced with the mass of the test model support component 60, thus achieving mass balancing of the test model support component 60. The second shut-off valve 36 and the relief valve 35 are also used for depressurization of the hydraulic cylinder 40. Both the first shut-off valve and the second shut-off valve 36 can be two-way shut-off valves.

[0036] In the test support device mass balancing drive system 100 of the present invention, since it has two second accumulators and two hydraulic cylinders 40, the two hydraulic cylinders 40 support the test model support component 60, and the pressure difference between the two second accumulators can balance the mass of the test model support component 60, so that the test piece installed on the test model support component 60 is not affected by the test model support component 60 during the flow field test. That is, the test support device mass balancing drive system 100 can realize the balancing of the mass of the test model support component during the heave motion process of the flow field test, and the mass of the test model support component does not affect the model test. Furthermore, the frequency of the balancing motion can be adjusted by adjusting the pressure of the balancing accumulator, that is, adjusting the pressure of the second accumulator, thereby achieving wide-frequency mass balancing from low frequency to high frequency.

[0037] In some alternative embodiments of the invention, each oil supply branch pipe 22 is connected to an overflow valve 35, and each overflow valve 35 is connected to the return oil main pipe 23 via a return oil branch pipe.

[0038] In some embodiments of the present invention, the relief valve 35 may be an electro-proportional relief valve, and by adjusting the pressure set by the relief valve 35, the output force of the heave balance hydraulic cylinder 40 and the gravity of the test model support component 60 are balanced.

[0039] In some embodiments of the present invention, each oil distribution pipe 22 is provided with a hydraulic lock 37, a second accumulator is connected to the pipe section of the oil distribution pipe 22 between the hydraulic lock 37 and the first shut-off valve, and a corresponding overflow valve 35 is connected to the pipe section of the oil distribution pipe 22 between the hydraulic lock 37 and the first shut-off valve.

[0040] In some embodiments of the present invention, a pressure reducing valve 38 is provided on the section of the oil main 21 between the connection point of the first accumulator 24 and the first shut-off valve, and the pressure reducing valve 38 is also connected to the return oil main 23.

[0041] A safety valve 39 is connected to the section of the oil supply branch pipe 22 located between the hydraulic lock 37 and the oil chamber. The safety valve 39 is connected to the return oil main pipe 23. The safety valve 39 can be a direct-acting relief valve, which can be connected to the oil circuit of the hydraulic cylinder 40 used for heave balancing. The safety protection of the hydraulic cylinder 40 can be achieved by setting the relief pressure.

[0042] In some embodiments of the present invention, a first pressure sensor 51 is connected to the section of the main oil pipeline 21 between the pressure reducing valve 38 and the first shut-off valve to detect the pressure of the main oil pipeline 21 after pressure reduction by the pressure reducing valve 38. A second pressure sensor 52 is connected to the section of the branch oil pipeline 22 connected to the relief valve 35 between the connection point of the first shut-off valve and the relief valve 35 to detect the pressure of the corresponding second accumulator. A third pressure sensor 53 is connected to the section of the branch oil pipeline 22 between the safety valve 39 and the oil chamber to detect the pressure of the oil chamber of the hydraulic cylinder 40. There are two third pressure sensors 53, which detect the pressure of the rodless chamber and the rod chamber, respectively.

[0043] In some embodiments of the present invention, the test support device mass balancing drive system 100 further includes a hydraulic lock control valve 45, which is connected to the oil supply main pipe 21, the hydraulic lock 37, and the return main pipe 23 via pipelines. The hydraulic lock control valve 45 may be a three-way solenoid valve, and the locking and unlocking of the heave balancing hydraulic cylinder 40 can be achieved by switching the three-way solenoid valve.

[0044] In some embodiments of the present invention, the test support device mass balancing drive system 100 further includes a guide rail clamp 55 and a clamp control valve 56. The clamp control valve 56 is connected via a pipeline to the main oil supply pipe 21, the guide rail clamp 55, and the return oil main pipe 23. A pressure reducing valve 57 is provided between the main oil supply pipe 21 and the clamp control valve 56. The clamp control valve 56 is a three-way solenoid shut-off valve. There may be four guide rail clamps 55. A guide rail clamp control oil circuit pressure sensor 58 is connected via a pipeline between the pressure reducing valve 38 and the clamp control valve 56. The pressure reducing valve 57 can reduce the pressure to the required working pressure.

[0045] like Figure 2 As shown, this embodiment of the invention also provides a flow field testing system, including an artificial flow field 70, a hydraulic cylinder 40, a helical motion guide rail 61, and a test model support component 60, as well as the test support device mass balancing drive system 100 in any of the above embodiments. The test model support component 60 is movably mounted on the helical motion guide rail 61. The output rod 41 of the hydraulic cylinder 40 is vertically arranged and connected to the test model support component 60. The outlets of the two oil supply pipes are respectively connected to the two oil chambers of the hydraulic cylinder 40.

[0046] like Figure 2As shown, in some embodiments of the present invention, there are two hydraulic cylinders 40, respectively disposed on both sides of the test model support component 60. The lower end of the cylinder body of the hydraulic cylinder 40 is universally connected to the artificial flow field 70. Specifically, a fixed base is provided in the artificial flow field, and the lower end of the cylinder body of the hydraulic cylinder 40 is universally connected to the fixed base through a ball joint. The upper end of the output rod 41 is universally connected to the test model support component 60. Specifically, a ball joint is provided between the upper end of the output rod 41 and the test model support component 60. An upper limit buffer 65 is provided on the upper side of the test model support component 60, and a lower limit buffer 66 is provided on the lower side. A guide rail clamp 55 is installed between the test model support component 60 and the floating motion guide rail 61, and the guide rail clamp 55 moves with the test model support component 60.

[0047] This invention also provides a mass balancing method using the test support device mass balancing drive system 100 in any of the above embodiments, comprising:

[0048] Adjust the charging pressure of the two second accumulators.

[0049] Hydraulic oil is first charged into one of the second accumulators in a preset sequence, and then hydraulic oil is charged into the other second accumulator.

[0050] The input of hydraulic oil controls the output rod 41 of the hydraulic cylinder 40 to move upward, and controls the speed at which the output rod 41 moves upward.

[0051] Control the overflow valve 35 to adjust the pressure difference between the two second accumulators.

[0052] Conduct flow field tests.

[0053] Because it has two second accumulators and two hydraulic cylinders 40, the two hydraulic cylinders 40 support the test model support component 60. The pressure difference between the two second accumulators can balance the mass of the test model support component 60, so that the test piece installed on the test model support component 60 is not affected by the test model support component 60 during the flow field test. That is, the mass balancing drive system 100 of this test support device can achieve the balancing of the mass of the test model support component 60 during the heave motion of the flow field test, and the mass of the test model support component 60 does not affect the model test. Furthermore, the frequency of the balancing motion can be adjusted by adjusting the pressure of the balancing accumulator, that is, adjusting the pressure of the second accumulator, thus achieving wide-frequency mass balancing from low frequency to high frequency.

[0054] Specifically, in some embodiments of the present invention, the two second accumulators are a first balancing accumulator 31 and a second balancing accumulator 32. The first balancing accumulator 31 is used to control the rodless chamber 43 of the hydraulic cylinder 40, and the second balancing accumulator 32 is used to control the rod chamber 42 of the hydraulic cylinder 40. The first balancing accumulator 31 is used in conjunction with the relief valve 35. The first shut-off valves are a first two-way shut-off valve 33 for controlling the rodless chamber 43 and a second two-way shut-off valve 34 for controlling the rod chamber 42.

[0055] Quality balancing methods include:

[0056] Adjust the charging pressure of the first balancing accumulator 31 and the second balancing accumulator 32 to match the system operating frequency; the higher the operating frequency, the higher the charging pressure.

[0057] Adjust the pressure of both safety valves to the safety protection pressure.

[0058] Before the start, the test model support component 60 and the test specimen on the test model support component 60 are in the lowest position and rest on the lower limit buffer 66. The clamp control valve 56 is de-energized and the guide rail clamp 55 clamps.

[0059] After starting work, first energize the second two-way shut-off valve 34 to fill the second balance accumulator 32 of the rod chamber 42 of the hydraulic cylinder 40 with oil. The filling pressure is determined according to the debugging situation.

[0060] After the second balancing accumulator 32 and the rod chamber 42 are filled with oil, the clamp control valve 56 is energized, the guide rail clamp 55 is released, the second two-way shut-off valve 34 is de-energized, the hydraulic lock control valve 45 is energized, the hydraulic lock 37 is opened, the first two-way shut-off valve 33 is energized, and the system fills the first balancing accumulator 31 of the rodless chamber 43 with oil. When the oil filling pressure reaches a certain value, the test model support component 60 moves upward, and the speed of movement is adjusted by the overflow valve 35.

[0061] After the test model support component 60 and the test specimen on it reach the neutral position, the first two-way shut-off valve 33 is de-energized. The pressure difference of the hydraulic cylinder 40 is adjusted through the overflow valve 35, that is, the pressure difference between the first balancing accumulator 31 and the second balancing accumulator 32 is adjusted so that the pressure difference balances the weight of the test model support component 60. The pressure difference value is determined according to the actual situation.

[0062] After adjustment, clamp control valve 56 is de-energized, guide rail clamp 55 clamps, hydraulic lock control valve 45 is de-energized, hydraulic lock 37 closes, and waits for flow field adjustment.

[0063] After the flow field adjustment is completed, the hydraulic lock control valve 45 is energized, the hydraulic lock 37 is opened, the clamp control valve 56 is energized, the guide rail clamp 55 is released, and the heave motion degree of freedom is released.

[0064] With external flow field adjustment, the test model support component 60 performs heave motion at different frequencies along the heave motion guide rail 61 in the vertical direction.

[0065] When the system detects an anomaly or a sudden stop by human intervention, it de-energizes the clamp control valve 56 and the hydraulic lock control valve 45, locking the sway motion within a short period of time.

[0066] When the flow field test ends normally, the second shut-off valve 36 is energized, the second balance accumulator 32 releases oil, the overflow valve 35 is adjusted to release oil from the first balance accumulator 31, the test model support component 60 and the test piece slowly descend to the lower limit due to gravity, the clamp control valve 56 is de-energized, and the hydraulic lock control valve 45 is de-energized, locking the swaying motion.

[0067] Therefore, those skilled in the art should recognize that although numerous exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Thus, the scope of the present invention should be understood and construed as covering all such other variations or modifications.

Claims

1. A flow field testing system, comprising a flow field, characterized in that, Also includes: Hydraulic cylinders, heave motion guide rails and test model support components, as well as the mass balancing drive system for the test support device; The test support device mass balancing drive system includes a main oil supply pipe, two branch oil supply pipes, and a return oil supply pipe; A first accumulator is connected to the main oil pipeline; Each of the oil delivery branches is connected to the main oil delivery branch via a first shut-off valve, and each oil delivery branch is connected to a second accumulator; the outlets of the two oil delivery branches are respectively connected to the two oil chambers of the hydraulic cylinder; wherein... One of the oil delivery branches is connected to an overflow valve, which is connected to the main oil return branch via a first return branch. Another oil delivery branch is connected to the main oil return branch via a second return branch, and a second shut-off valve is provided on the second return branch. Alternatively, each of the oil delivery branches is connected to an overflow valve, and each overflow valve is connected to the main oil return branch via a return branch. The test model support component is movably mounted on the swaying motion guide rail, the output rod of the hydraulic cylinder is vertically set, and the output rod is connected to the test model support component; the outlets of the two oil supply pipes are respectively connected to the two oil chambers of the hydraulic cylinder.

2. The flow field testing system according to claim 1, characterized in that, Each of the oil delivery branches is equipped with a hydraulic lock, the second accumulator is connected to the section of the oil delivery branch between the hydraulic lock and the first shut-off valve, and the corresponding overflow valve is connected to the section of the oil delivery branch between the hydraulic lock and the first shut-off valve.

3. The flow field testing system according to claim 2, characterized in that, A pressure reducing valve is installed on the section of the main oil pipeline between the connection point of the first accumulator and the first shut-off valve. The pressure reducing valve is also connected to the return oil pipeline. A safety valve is connected to the section of the oil supply branch pipe located between the hydraulic lock and the oil chamber, and the safety valve is connected to the return oil main pipe.

4. The flow field testing system according to claim 3, characterized in that, A first pressure sensor is connected to the section of the main oil pipeline between the pressure reducing valve and the first shut-off valve. A second pressure sensor is connected to the oil delivery branch pipe connected to the overflow valve, on the pipeline between the connection point of the first shut-off valve and the overflow valve; A third pressure sensor is connected to the section of the oil delivery pipe located between the safety valve and the oil chamber.

5. The flow field testing system according to claim 2, characterized in that, It also includes a hydraulic lock control valve, which is connected to the main oil supply pipe, the hydraulic lock, and the main oil return pipe via pipelines.

6. The flow field testing system according to claim 1, characterized in that, It also includes a guide rail clamp and a clamp control valve; the clamp control valve is connected to the main oil supply pipe, the guide rail clamp and the main oil return pipe through a pipeline.

7. The flow field testing system according to claim 6, characterized in that, There are two hydraulic cylinders, which are respectively arranged on both sides of the test model support component; the lower end of the cylinder body of the hydraulic cylinder is universally connected to the fixed base; the upper end of the output rod is universally connected to the test model support component. The upper side of the test model support component is provided with an upper limit buffer, and the lower side is provided with a lower limit buffer. The guide rail clamp is installed between the test model support component and the heave motion guide rail, and the guide rail clamp moves with the test model support component.

8. A method for mass balancing using the flow field test system according to any one of claims 1 to 7, characterized in that, include: Adjust the charging pressure of the two second accumulators; Hydraulic oil is first charged into one of the second accumulators in a preset sequence, and then hydraulic oil is charged into the other second accumulator. The hydraulic oil is input to control the output rod of the hydraulic cylinder to move upward, and the speed at which the output rod moves upward is also controlled. The overflow valve is controlled to adjust the pressure difference between the two second accumulators; Conduct flow field tests.

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