Dynamic pressure testing device and method based on equivalent pressure guide pipe

Abstract

The invention discloses a dynamic pressure testing device and method based on an equivalent pressure guiding pipe, and relates to the technical field of aero-engine testing. On the basis of the impedance method theory, a frequency domain mathematical model of a tested system pipeline is established in a combination and equivalent mode, optimal equivalent pressure guide pipe design parameters under the current working condition are obtained with the help of the impedance method theory and a corresponding simulation tool, checking and verification are conducted through tests, and the optimal equivalent pressure guide pipe design parameters are obtained. Finally, the purpose of indirectly testing the dynamic pressure of the system in an equivalent pressure guiding pipe mode is achieved, the dynamic pressure measuring method is provided especially for a high-temperature environment, a large-load vibration environment or other special occasions where a pressure sensor cannot be directly installed, and the equivalent measuring method is proposed for the first time in the industry and has a wide application prospect. And the method has very high application value.

Description

Technical Field

[0001] The invention belongs to the technical field of aero-engine testing, and in particular relates to a dynamic pressure testing device and method based on an equivalent pressure-leading tube. Background Art

[0002] In the process of conducting dynamic characteristic research on mechanical hydraulic products of aircraft engines, it is necessary to test and study the pressure pulsation and dynamic response characteristics of the product or system. Usually, a high-frequency dynamic pressure sensor is directly installed on the system or pipeline under test for testing. However, for special occasions such as high temperature environment, large load vibration environment or other special occasions where pressure sensors cannot be directly installed, pressure fluctuations must be indirectly tested through pressure pipes. Since the introduction of pressure pipes will change the dynamic characteristics of the system, and the design parameters of the pressure pipes have a great influence on the test results, there is currently no proper solution in the industry. Summary of the invention

[0003] Based on the above background, a dynamic pressure testing method based on an equivalent pressure-leading tube is provided, which realizes a method for indirectly testing the dynamic pressure of a system by means of an equivalent pressure-leading tube.

[0004] In view of this, according to one aspect of an embodiment of the present invention, a dynamic pressure testing device based on an equivalent pressure pipe is provided, including: a first connecting pipeline 2, a pressure pipe connecting valve block 3, a second connecting pipeline 4, a pressure regulating device 5, an equivalent pressure pipe 6, a high-frequency pressure sensor 7 and a data acquisition system 8, wherein the first connecting pipeline 2 is used to connect the system under test 1, the pressure pipe connecting valve block 3 is respectively connected to the first connecting pipeline 2, the second connecting pipeline 4 and the equivalent pressure pipe 6, the high-frequency pressure sensor 7 is installed at the end of the equivalent pressure pipe 6, and is used to collect the pressure at the end of the equivalent pressure pipe 6, the pressure regulating device 5 is used to adjust the pressure of the system under test 1, and the data acquisition system 8 is used to collect test data.

[0005] Optionally, the frequency response bandwidth of the high-frequency pressure sensor 7 should be more than 10 times the pulsation frequency of the measured system 1.

[0006] Optionally, the sampling frequency of the data acquisition system 8 is at least 10 times the frequency of the tested signal.

[0007] According to another aspect of an embodiment of the present invention, a dynamic pressure testing method based on an equivalent pressure-inducing tube is provided, characterized in that any of the above-mentioned devices is used, including:

[0008] Step S1: determining the distance from the equivalent pressure-conducting pipe 6 to the target position of the measured system 1;

[0009] Step S2: determining the distance from the target position to the pressure regulating device 5;

[0010] Step S3: determining the opening of the voltage regulating device 5 in each state by equivalent calculation or actual measurement, so as to calculate the impedance of the voltage regulating device 5;

[0011] Step S4: establishing an impedance model;

[0012] Step S5: simulating and calculating the optimal pressure-conducting pipe length and pipe diameter parameters;

[0013] Step S6: setting up multiple groups of experiments for verification according to the simulation results.

[0014] Optionally, step S4 also includes: treating the system as equivalent to a one-dimensional straight pipe, a blind-end cavity, a series cavity, a parallel cavity, and a series combination of throttling holes, and establishing mathematical models of each equivalent part respectively.

[0015] Optionally, the mathematical model of the one-dimensional straight pipe includes: the pressure and flow rate of the fluid at both ends of the one-dimensional straight pipe are P1(s), Q1(s) and P2(s), Q2(s), respectively. According to the basic equation of the dynamic characteristics of the fluid delivery pipeline, the transfer matrix G(s) between any two sections of the one-dimensional straight pipe can be expressed as:

[0016]

[0017] Where Г(s) is the propagation operator, Z0(s) is the characteristic impedance, and s is a complex parameter.

[0018] Optionally, the mathematical model of the blind-end cavity includes: regarding the blind-end pipe as a one-dimensional straight pipe with a terminal flow rate of 0, that is, Q2(s)=0.

[0019] Optionally, the mathematical model of the series cavities includes: according to the propagation property of the liquid pressure, it is considered that the pressure inside the cavity is equal everywhere, that is, P1(s)=P2(s)=P(s), and the transfer matrix G(s) of the series cavities is:

[0020]

[0021] Where K is the bulk elastic modulus of the liquid and V is the volume of the cavity.

[0022] Optionally, the mathematical model of the throttle hole includes:

[0023]

[0024] Among them, C q is the flow coefficient, A2 is the cross-sectional area of ​​the throttle hole, ΔP is the pressure difference on both sides of the throttle hole, ρ is the oil density, Q(s) and P(s) respectively represent the flow rate and pressure at a certain point of the throttle hole.

[0025] Optionally, step S6 further includes: setting equivalent pressure-guiding pipes with the same inner diameter and different wall thicknesses, and comparing the influence of pipeline stiffness on the test results.

[0026] The designed method of measuring the dynamic pressure of the system by using an equivalent pressure pipe can measure the dynamic pressure of the system in high temperature environment, high load vibration environment or other special occasions where the pressure sensor cannot be directly installed, and the dynamic pressure test value is highly consistent with the test value of the directly installed pressure sensor. Based on the impedance method theory, a frequency domain mathematical model of the test pipeline system is established by combining and equivalent methods. With the help of the impedance method theory and corresponding simulation tools, the optimal equivalent pressure pipe design parameters under the current working conditions are obtained, and then verified through experiments, and finally the purpose of indirectly testing the dynamic pressure of the system by using the equivalent pressure pipe is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a simple model of the test system.

[0028] Figure 2 This is the equivalent pressure pipe operation flow chart.

[0029] Figure 3 Schematic diagram of a one-dimensional straight tube.

[0030] Figure 4 Schematic diagram of the transfer matrix for series elements.

[0031] Figure 5 Schematic diagram of a blind-end pipe.

[0032] Figure 6 Schematic diagram of the series chamber.

[0033] Figure 7 Schematic diagram of parallel cavities.

[0034] Figure 8 Schematic diagram of the throttle hole.

[0035] Fig. 9 This is a simple model diagram of a test system without a pressure pipe.

[0036] Description of reference numerals:

[0037] 1-tested system; 2-first connecting pipeline, 4-second connecting pipeline; 3-pressure-guiding pipe connecting valve block, 5-pressure regulating device, 6-equivalent pressure-guiding pipe, 7-high-frequency pressure sensor, 8-data acquisition system. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] According to one aspect of an embodiment of the present invention, a dynamic pressure testing device based on an equivalent pressure pipe is provided, comprising: a first connecting pipeline 2, a pressure pipe connecting valve block 3, a second connecting pipeline 4, a pressure regulating device 5, an equivalent pressure pipe 6, a high-frequency pressure sensor 7 and a data acquisition system 8, wherein the first connecting pipeline 2 is used to connect the system under test 1, the pressure pipe connecting valve block 3 is respectively connected to the first connecting pipeline 2, the second connecting pipeline 4 and the equivalent pressure pipe 6, the high-frequency pressure sensor 7 is installed at the end of the equivalent pressure pipe 6, and is used to collect the pressure at the end of the equivalent pressure pipe 6, the pressure regulating device 5 is used to adjust the pressure of the system under test 1, and the data acquisition system 8 is used to collect test data.

[0040] Based on the impedance method theory, a dynamic pressure test method based on an equivalent pressure tube is designed in high temperature environment, large load vibration environment or other places where it is impossible to directly install a pressure sensor to measure the dynamic pressure of the system. The dynamic pressure of the system is indirectly tested by means of an equivalent pressure tube, providing a new method for dynamic pressure testing.

[0041] Furthermore, the frequency response bandwidth of the high-frequency pressure sensor 7 should be more than 10 times the pulsation frequency of the measured system 1; further, the sampling frequency of the data acquisition system 8 should be at least more than 10 times the frequency of the measured signal.

[0042] According to another aspect of an embodiment of the present invention, a dynamic pressure testing method based on an equivalent pressure-inducing tube is provided, characterized in that any of the above-mentioned devices is used, including:

[0043] Step S1: determining the distance from the equivalent pressure-conducting pipe 6 to the target position of the measured system 1;

[0044] Step S2: determining the distance from the target position to the pressure regulating device 5;

[0045] Step S3: determining the opening of the voltage regulating device 5 in each state by equivalent calculation or actual measurement, so as to calculate the impedance of the voltage regulating device 5;

[0046] Step S4: establishing an impedance model;

[0047] Step S5: simulating and calculating the optimal pressure-conducting pipe length and pipe diameter parameters;

[0048] Step S6: setting up multiple groups of experiments for verification according to the simulation results.

[0049] Furthermore, step S4 also includes: treating the system as equivalent to a one-dimensional straight pipe, a blind-end cavity, a series cavity, a parallel cavity, and a series combination of throttling holes, and establishing mathematical models of each equivalent part respectively.

[0050] Furthermore, the mathematical model of the one-dimensional straight pipe includes: the pressure and flow rate of the fluid at both ends of the one-dimensional straight pipe are P1(s), Q1(s) and P2(s), Q2(s), respectively. According to the basic equation of the dynamic characteristics of the fluid delivery pipeline, the transfer matrix G(s) between any two sections of the one-dimensional straight pipe can be expressed as:

[0051]

[0052] Where Г(s) is the propagation operator, Z0(s) is the characteristic impedance, and s is a complex parameter.

[0053] Furthermore, the mathematical model of the blind-end cavity includes: regarding the blind-end pipe as a one-dimensional straight pipe with a terminal flow rate of 0, that is, Q2(s)=0.

[0054] Furthermore, the mathematical model of the series cavity includes: according to the propagation property of liquid pressure, it is assumed that the pressure inside the cavity is equal everywhere, that is, P1(s)=P2(s)=P(s), and the transfer matrix G(s) of the series cavity is:

[0055]

[0056] Where K is the bulk elastic modulus of the liquid and V is the volume of the cavity.

[0057] Furthermore, the mathematical model of the throttle hole includes:

[0058]

[0059] Among them, C q is the flow coefficient, A c is the cross-sectional area of ​​the throttle hole, ΔP is the pressure difference on both sides of the throttle hole, ρ is the oil density, Q(s) and P(s) respectively represent the flow rate and pressure at a certain point of the throttle hole.

[0060] Furthermore, step S6 also includes: setting equivalent pressure-guiding pipes with the same inner diameter and different wall thicknesses, and comparing the influence of pipe stiffness on the test results.

[0061] Example 1

[0062] First, according to the impedance method mentioned in this patent, in the hydraulic system, impedance Z is defined as the ratio of pressure P and flow Q, that is, Z(s) = P(s) / Q(s). The larger the impedance value, the greater the pressure change caused by the arrival of unit flow. Therefore, in the study of the frequency domain characteristics of fluid pulsation, the impedance of a certain point obtained by calculation can be used to approximate the frequency domain characteristics of that point: the larger the impedance value, the greater the fluid pulsation of the system. Based on the theory of impedance method, according to the components of the test system, the impedance mathematical model of the system under test is established by combination and equivalent methods, and the impedance Z0 of the target position of the system under test without the pressure pipe and the impedance Z of the blind end of the pressure pipe are calculated. b, find Z0 and Z b The parameters such as the position, length, and diameter of the pressure lead pipe with the smallest difference can be used to determine the parameters of the equivalent pressure lead pipe, and then measure the dynamic pressure of the system in high temperature environment, large load vibration environment or other special occasions where the pressure sensor cannot be directly installed.

[0063] Figure 1 This is a simple model of a dynamic pressure test system. The dynamic pressure test system can be simplified into several components, namely: a system under test 1, a first connecting pipeline 2, a second connecting pipeline 4, a pressure pipe connecting valve block 3, a pressure regulating device 5, an equivalent pressure pipe 6, a high-frequency pressure sensor 7, and a data acquisition system 8. Among them, the first connecting pipeline 2 is used to connect the pipeline of the system under test, the pressure pipe connecting valve block 3 connects the first connecting pipeline 2, the second connecting pipeline 4 and the equivalent pressure pipe 6 respectively, and the high-frequency pressure sensor 7 is installed at the end of the equivalent pressure pipe 6 to collect the pressure at the end of 6. The pressure regulating device 5 is used to adjust the pressure of the system under test 1. The frequency response bandwidth of the high-frequency pressure sensor 7 should be more than 10 times the pulsation frequency of the system under test; the sampling frequency of the data acquisition system 8 is also at least 10 times the frequency of the signal under test.

[0064] Figure 1 Where L1 represents the distance from the target position of the tested system to the equivalent pressure-leading pipe 6, and L1 should be as small as possible; L2 represents the length of the equivalent pressure-leading pipe 6; L3 represents the distance from the equivalent pressure-leading pipe 6 to the pressure-regulating device of the tested system in the pipeline direction; G1, G2, and G3 respectively represent the pipeline transfer matrices of the three sections of equivalent pipelines (the transfer matrices are all 2*2 matrices).

[0065] Figure 2 The specific operation process of the dynamic pressure test method based on the equivalent pressure pipe is as follows:

[0066] S1: Determine the distance L1 from the equivalent pressure-inducing pipe (6) to the target position of the measured system (1).

[0067] S2: Determine the distance from the target position to the pressure regulating device (5), i.e., L1+L3.

[0068] S3: Determine the opening of the voltage regulating device in each state through equivalent calculation or actual measurement to calculate the impedance of the voltage regulating device.

[0069] S4: Based on the impedance method theory, a system impedance model is established for simulation. The impedance model establishment method is as follows:

[0070] The pipeline system can be equivalent to a one-dimensional straight pipe ( Figure 3 )、Blind End Cavity( Figure 5 ), series chamber ( Figure 6 ), parallel cavity ( Figure 7 ), throttle hole ( Figure 8) in series, and establish mathematical models of each equivalent part respectively.

[0071] Figure 3 The pressure and flow rate of the fluid at both ends of the one-dimensional straight pipe are P1(s), Q1(s) and P2(s), Q2(s) respectively. According to the basic equation of the dynamic characteristics of the fluid delivery pipeline, the transfer matrix G(s) between any two sections of the one-dimensional straight pipe can be expressed as:

[0072]

[0073] Where Г(s) is the propagation operator, Z0(s) is the characteristic impedance, and s is the complex parameter

[0074] Figure 4 This is a schematic diagram of the transfer matrix of series elements. The flow and pressure relationships between the various parts of the series system are:

[0075]

[0076] Figure 4 The transfer matrix of the series pipeline is:

[0077] G(s)=G1(s)*G2(s)*G3(s)

[0078] When the transfer matrix between any two points in the piping system is known, the following formula is obtained:

[0079]

[0080] Among them, P1(s) and Q1(s) are the upstream pressure flow, and P2(s) and Q2(s) are the downstream pressure flow. Z1(s) and Z2(s) are used to represent the upstream and downstream impedances respectively, so we can deduce

[0081]

[0082] Statement: G ij Represents the element in the i-th row and j-th column of G.

[0083] It can be concluded that in a piping system, if the impedance of a certain point and the transfer matrix between it and any other point are known, the impedance of another point can be solved.

[0084] Figure 5 This is a schematic diagram of a blind-end pipe. For a blind-end pipe, it can be regarded as a one-dimensional straight pipe with a terminal flow rate of 0. Figure 1 The equivalent pressure-leading pipe 6 in the figure can be regarded as a blind-end pipe, that is, Q2(s)=0. According to the above formula, the impedance of the blind-end pipe can be obtained as:

[0085]

[0086] Figure 6 This is a schematic diagram of the series cavity. Because the pressure-inducing pipe needs to be installed, the pressure-inducing pipe connecting valve block 3 is a hollow structure with a cavity. According to the propagation properties of liquid pressure, it can be approximately considered that the pressure inside the cavity is equal everywhere, that is:

[0087] P1(s)=P2(s)=P(s)

[0088] The pressure change equation in the cavity is:

[0089]

[0090] Where Q1 and Q2 are the flow rates at the inlet and outlet of the cavity, K is the bulk elastic modulus of the liquid, V is the volume of the cavity, and P is the pressure inside the cavity. After Laplace transformation, we get:

[0091]

[0092] The flow-pressure relationship at both ends of the series chamber can be expressed as:

[0093]

[0094] Therefore, the transfer matrix G(s) of the series cavity is:

[0095]

[0096] In actual installation, the pressure-conducting pipe connecting valve block 3 is connected in series in the pipeline system, but the equivalent pressure-conducting pipe 6 is connected in parallel in the pipeline system, so another type of cavity, namely the parallel cavity, will be generated, as shown in the schematic diagram. Figure 7 As shown in the figure, the pressure and flow at both ends of the transition connection structure between the parallel cavity and the main pipeline are P3(s), Q3(s), P4(s), and Q4(s). Since the parallel cavity has only one liquid inlet, there is a pressure change equation for the cavity:

[0097]

[0098] Where K4 is the bulk elastic modulus of the liquid, V4 is the volume of the cavity, and after Laplace transformation, the impedance of the cavity can be obtained as:

[0099]

[0100] P3(s), Q3(s) and P4(s), Q4(s) have the following relationship:

[0101]

[0102] Where Г3(s) is the propagation operator, Z 03(s) is the characteristic impedance, s is a complex parameter, and the inlet impedance of the transition connection structure Z3(s) can be obtained by substituting it into the formula:

[0103]

[0104] As for the relationship between pressure and flow at the three ports of the parallel cavity, Kirchhoff's law can be obtained:

[0105] P1(s)=P2(s)=P3(s)

[0106] Q1(s)=Q2(s)+Q3(s)

[0107] Substituting into the impedance expression we get:

[0108]

[0109]

[0110] Among them, Z1(s), Z2(s), and Z3(s) are the impedances of the three ports respectively. Through the impedance relationship between the ports, the pressure flow transfer matrix between the inlet and outlet of the pipeline can be obtained:

[0111]

[0112] Combining the above formula, the transfer matrix of the parallel cavity can be calculated as:

[0113]

[0114] For the pressure regulating device of the system under test, it can be regarded as a throttle hole, as shown in the schematic diagram. Figure 8 shown.

[0115] The relationship between flow rate Q(s) and pressure P(s) at a certain point of the throttle hole:

[0116]

[0117] Among them, C q is the flow coefficient, A c is the cross-sectional area of ​​the throttle hole, ΔP is the pressure difference on both sides of the throttle hole, and ρ is the oil density.

[0118] Combining the above formula, the pressure and flow transfer matrix at both ends of the throttle hole can be obtained:

[0119]

[0120] Therefore, the throttle transfer matrix G(s) is:

[0121]

[0122] In the case of a pressure lead pipe, calculate the blind end impedance Z of the pressure lead pipe b The target location flow is Q s , pressure is P s , the flow rate at the pressure regulating device is Q z , pressure is P z , the pressure at the blind end is P0, the flow is 0, the pressure at the inlet of the pressure pipe is P2, and the flow is Q2. According to the impedance theory, we can get:

[0123]

[0124] It can be concluded that:

[0125] P2=G 3,11 *P z +G 3,12 *Q z

[0126] P2=G 2,11 *P0

[0127] Q2=G 2,21 *P0

[0128] According to the parallel impedance theory, the transfer matrix of the parallel pressure-inducing tube can be obtained:

[0129]

[0130] Then the relationship from the target position to the pressure regulating device is as follows:

[0131]

[0132] G f It is an intermediate variable in the derivation process when the blind-end pipe is regarded as the end load, and it can be deduced that:

[0133] Q s =G f,21 *P z +G f,22 *Q z

[0134] Combining the above formula, we can get:

[0135]

[0136] Among them, the impedance at the voltage regulator is:

[0137]

[0138] Therefore, in the case of a pressure lead pipe, the impedance Z of the blind end of the pressure lead pipe is b for:

[0139]

[0140] Fig. 9 This is a simple model of the test system without a pressure pipe. First, in the absence of a pressure pipe, the impedance Z0 of the target position of the system under test is calculated as follows: The flow rate at the target position is Q s , pressure is P s , the flow rate at the pressure regulating device is Q z , pressure is P z According to the series theory, the transfer matrix G from the target position to the voltage regulating device is s for:

[0141] G s =G1*G3

[0142] So there exists the following formula:

[0143]

[0144] It can be concluded that:

[0145] P s =G s,11 *P z +G s,12 *Q z

[0146] Q s =G s,21 *P z +G s,22 *Q z

[0147] Comparing the two equations, the impedance Z0 at the outlet of the measured system without a pressure-inducing pipe is:

[0148]

[0149] So far, the mathematical model of the pipeline impedance of the tested system has been successfully established.

[0150] S5: Simulate and calculate the optimal pressure pipe length and diameter parameters: set a set of pressure pipe length and diameter parameters, impedance Z0 and the blind end impedance Z of the pressure pipe b , compare the impedance Z0 of the target position of the system under test without the lead pipe and the impedance Z0 of the blind end of the lead pipe b As a result, find Z0 and Z b Parameters of the length and diameter of the pressure-supply pipe when the difference is minimal.

[0151] S6: According to the results, multiple groups of tests are set up for verification to prove the effectiveness of the simulation and increase the reliability of the results. You can also set up equivalent pressure-inducing pipes with the same inner diameter and different wall thicknesses to set the effect of the stiffness of the control pipe on the test results.

[0152] Example 2

[0153] Simulate and calculate the optimal pressure pipe length and diameter parameters: set a set of pressure pipe length and diameter parameters, impedance Z0 and pressure pipe blind end impedance Z b , compare the impedance Z0 of the target position of the system under test without the lead pipe and the impedance Z0 of the blind end of the lead pipe b The result is shown in the following code to find Z0 and Z b Parameters of the length and diameter of the pressure-supply pipe when the difference is minimal.

[0154]

[0155] % The measuring point is the end

[0156] Z_hb1=1 / G2(1,1)*(G3(1,1)*Zz+G3(1,2)) / (Gf(2,1)*Zz+Gf(2,2));

[0157] Zhb1(i)=abs(Z_hb1);

[0158] The above is only a specific embodiment of the present invention, and the present invention is described in detail. The unexplained part is a conventional technology. However, the protection scope of the present invention is not limited to this. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. The protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A dynamic pressure testing device based on an equivalent pressure-inducing tube, characterized in that: include: A first connecting pipeline (2), a pressure-guiding pipe connecting valve block (3), a second connecting pipeline (4), a pressure regulating device (5), an equivalent pressure-guiding pipe (6), a high-frequency pressure sensor (7) and a data acquisition system (8), wherein the first connecting pipeline (2) is used to connect the system under test (1), the pressure-guiding pipe connecting valve block (3) is respectively connected to the first connecting pipeline (2), the second connecting pipeline (4) and the equivalent pressure-guiding pipe (6), the high-frequency pressure sensor (7) is installed at the end of the equivalent pressure-guiding pipe (6) and is used to collect the pressure at the end of the equivalent pressure-guiding pipe (6), the pressure regulating device (5) is used to adjust the pressure of the system under test (1), and the data acquisition system (8) is used to collect test data.

2. The device according to claim 1, characterized in that The frequency response bandwidth of the high-frequency pressure sensor (7) should be more than 10 times the pulsation frequency of the measured system (1).

3. The device according to claim 1, characterized in that The sampling frequency of the data acquisition system (8) is at least 10 times the frequency of the signal being tested.

4. A dynamic pressure testing method based on an equivalent pressure-inducing tube, characterized in that: Use of any of the devices described in claims 1-3, comprising: Step S1: determining the distance from the equivalent pressure-conducting pipe (6) to the target position of the system under test (1); Step S2: determining the distance from the target position to the pressure regulating device (5); Step S3: Determine the opening of the pressure regulating device (5) in each state by equivalent calculation or actual measurement. Used to calculate the impedance of the voltage regulating device (5); Step S4: establishing an impedance model; Step S5: simulating and calculating the optimal pressure-conducting pipe length and pipe diameter parameters; Step S6: setting up multiple groups of experiments for verification according to the simulation results.

5. The method according to claim 4, characterized in that Step S4 also includes: treating the system as equivalent to a one-dimensional straight pipe, a blind-end cavity, a series cavity, a parallel cavity, and a series combination of throttling holes, and establishing mathematical models of each equivalent part respectively.

6. The method according to claim 5, characterized in that The mathematical model of a one-dimensional straight tube includes: The pressure and flow rate of the fluid at both ends of a one-dimensional straight pipe are P1(s), Q1(s) and P2(s), Q2(s) respectively. According to the basic equation of the dynamic characteristics of the fluid delivery pipeline, the transfer matrix G(s) between any two sections of a one-dimensional straight pipe can be expressed as: Where Г(s) is the propagation operator, Z0(s) is the characteristic impedance, and s is a complex parameter.

7. The method according to claim 6, characterized in that The mathematical model of the blind-end cavity includes: the blind-end pipe is regarded as a one-dimensional straight pipe with a terminal flow rate of 0, that is, Q2(s)=0.

8. The method according to claim 6, characterized in that The mathematical model of the series cavity includes: according to the propagation properties of liquid pressure, it is assumed that the pressure inside the cavity is equal everywhere, that is, P1(s) = P2(s) = P(s), and the transfer matrix G(s) of the series cavity is: Where K is the bulk elastic modulus of the liquid and V is the volume of the cavity.

9. The method according to claim 6, characterized in that The mathematical model of the throttle hole includes: Among them, C q is the flow coefficient, A c is the cross-sectional area of ​​the throttle hole, ΔP is the pressure difference on both sides of the throttle hole, ρ is the oil density, Q(s) and P(s) respectively represent the flow rate and pressure at a certain point of the throttle hole.

10. The method according to claim 4, characterized in that Step S6 also includes: setting equivalent pressure-guiding pipes with the same inner diameter and different wall thicknesses, and comparing the influence of pipe stiffness on the test results.

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