Calibration device

Abstract

The invention relates to a calibration device. The calibration device comprises a container, a generator and a receiver. The container comprises a containing cavity used for containing liquid. The generator comprises a sound source located in the containing cavity. The sound source is used for generating underwater shock waves in the liquid. The receiver comprises a fixing clamp and a standard sensor located in the containing cavity. The standard sensor is used for receiving the underwater shock waves in the liquid; the fixing clamp comprises a first fixing part and a second fixing part which are located in the containing cavity. The standard sensor is connected to the first fixing part; the second fixing part is used for connecting a sensor to be calibrated in the liquid; wherein the central points of the first fixing part and the second fixing part are horizontally aligned with the sound center of the sound source.

Description

Technical Field

[0001] The present application relates to the field of underwater acoustic sensing, and in particular to a calibration device. Background Art

[0002] Underwater shock wave pressure sensor is a key equipment for measuring underwater shock pressure, which has great military and civilian value and significance. Underwater shock wave pressure sensor is widely used in the research and development and evaluation of underwater weapons, marine engineering, marine resource development and other fields. The accurate test of underwater shock wave pressure sensor depends on the accurate calibration of its related metrological characteristics (key dynamic parameters pressure sensitivity, rise time, peak pressure, etc.). Only when the underwater shock wave pressure sensor is accurately calibrated can the accuracy and reliability of the measurement results be guaranteed, thereby ensuring its effectiveness in military and civilian applications.

[0003] The dynamic calibration of underwater shock wave pressure sensors mainly includes shock tube dynamic calibration, drop weight dynamic pressure calibration, quasi-delta function pulse pressure calibration, quick opening valve calibration, relative dynamic calibration, etc. Among them, the dynamic calibration method of pressure sensor based on shock tube is the most commonly used calibration method. These methods are mainly focused on the air acoustic field, and do not consider the underwater environment characteristics applicable to underwater shock wave pressure sensors, that is, the incompressible characteristics of water.

[0004] There are few studies on the dynamic calibration technology of underwater shock wave pressure sensors, which mainly focus on the combination of water shock tube and relative dynamic calibration method. Usually, a TNT explosive sound source is arranged in the water shock tube to achieve dynamic pressure calibration. However, this method still has certain defects in multiple tests, cost and safety. Therefore, it is necessary to find a new dynamic calibration method for underwater shock wave pressure sensors to make up for the defects. Summary of the invention

[0005] The present application provides a calibration device to solve some or all of the deficiencies in the related art.

[0006] The present application provides a calibration device, comprising:

[0007] A container, comprising a cavity for containing a liquid;

[0008] A generator, comprising a sound source located in the cavity; the sound source is used to generate underwater shock waves in the liquid; and

[0009] A receiver, comprising a fixing fixture and a standard sensor located in the cavity; the standard sensor is used to receive the underwater shock wave in the liquid; the fixing fixture comprises a first fixing part and a second fixing part located in the cavity; the standard sensor is connected to the first fixing part; the second fixing part is used to connect to a sensor to be calibrated placed in the liquid;

[0010] Wherein, the center points of the first fixing portion and the second fixing portion are horizontally aligned with the sound center of the sound source.

[0011] Furthermore, the generator further comprises a rotating fixture; the rotating fixture comprises a rotating part; the sound source is fixed to the rotating part; the rotating part extends in a vertical direction and can rotate around a vertically extending rotating shaft.

[0012] Furthermore, the sound source is used to generate underwater spherical shock waves; and the fixing fixture extends in a vertical direction.

[0013] Furthermore, the distance between the standard sensor and the sound source in the horizontal direction is greater than or equal to 50 centimeters and less than or equal to 75 centimeters.

[0014] Furthermore, a distance between the first fixing portion and the second fixing portion is greater than or equal to 5 centimeters and less than or equal to 10 centimeters.

[0015] Furthermore, the distance between the sound source and the liquid surface of the liquid is greater than or equal to 5 centimeters and less than or equal to 15 centimeters.

[0016] Furthermore, the container also includes a silencer disposed on the wall surface of the cavity.

[0017] Further, the generator includes a plasma sound source control system connected to the sound source, for controlling the sound source to release shock waves; and / or,

[0018] The generator includes a voltage and current sampler connected to the sound source, and is used to monitor the voltage and current of the sound source.

[0019] Furthermore, the receiver includes a measuring amplifier and a collecting instrument which are electrically connected; the measuring amplifier is used to acquire and amplify the signals of the standard sensor and the sensor to be calibrated, and transmit them to the collecting instrument.

[0020] Furthermore, the calibration device further includes a controller; the controller is used to obtain the signal response of the standard sensor and the signal response of the sensor to be calibrated, and obtain the passband frequency according to the following formula:

[0021]

[0022] Among them, H1(jω) is the frequency domain dynamic characteristic of the standard sensor, H2(jω) is the frequency domain dynamic characteristic of the sensor to be calibrated, F[~] is Fourier transform, p1(t) is the signal response of the standard sensor, and p2(t) is the signal response of the sensor to be calibrated.

[0023] The technical solution provided by the embodiments of the present application may have the following beneficial effects:

[0024] It can be seen from the above embodiments that the sound source of the calibration device of the present application generates underwater shock waves, and the center points of the first fixed part and the second fixed part are horizontally aligned with the sound center of the sound source. This arrangement makes the direction and size of the sound waves received by the standard sensor located at the first fixed part and the sensor to be calibrated located at the second fixed part as similar as possible, thereby reducing the decrease in calibration accuracy caused by inconsistent received sound waves. In addition, the sound source can generate multiple sound waves, so compared to the way explosives generate sound waves, the sound source of the present application effectively reduces the cost of the calibration device, and the safety performance can also be improved.

[0025] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 A schematic diagram of the structure of an embodiment of the calibration device of the present application;

[0028] Figure 2 for Figure 1 A schematic diagram of the partial structure of the calibration device shown.

[0029] Description of reference numerals:

[0030] 100 calibration device, 1 container, 11 cavity, 12 silencer, 13 upper cover, 2 generator, 21 sound source, 22 rotating fixture, 23 signal generator, 24 plasma sound source control system, 25 voltage and current sampler, 3 receiver, 31 fixed fixture, 32 standard sensor, 33 measuring amplifier, 34 acquisition instrument, 4 sensor to be calibrated, 5 controller, X horizontal direction, Z vertical direction. DETAILED DESCRIPTION

[0031] Here, the technical solutions in the embodiments (or "implementations") of the present application will be described clearly and completely in conjunction with the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements.

[0032] If there are terms involving directional indications or positional relationships in the embodiments of the present application (such as up, down, left, right, front, back, inside, outside, top, bottom, center, vertical, horizontal, longitudinal, transverse, length, width, counterclockwise, clockwise, axial, radial, circumferential, etc.), such terms are only used to explain the relative positional relationship, movement, etc. between the components under a certain specific posture (as shown in the accompanying drawings); if the specific posture changes, the directional indication or positional relationship will also change accordingly. In addition, the terms "first", "second", etc. involved in the embodiments of the present application are only used for the purpose of convenience of description and cannot be understood as indicating or implying relative importance.

[0033] refer to Figure 1 and Figure 2 The present application provides a calibration device 100. The calibration device 100 includes a container 1, a generator 2 and a receiver 3. The container 1 includes a cavity 11 for containing liquid. The generator 2 includes a sound source 21 located in the cavity 11. The sound source 21 is used to generate underwater shock waves in the liquid. The receiver 3 includes a fixing fixture 31 and a standard sensor 32 located in the cavity 11. The standard sensor 32 is used to receive underwater shock waves in the liquid. The fixing fixture 31 includes a first fixing part and a second fixing part located in the cavity 11. The standard sensor 32 is connected to the first fixing part. The second fixing part is used to connect the sensor 4 to be calibrated located in the liquid. Among them, the center points of the first fixing part and the second fixing part are horizontally aligned with the sound center of the sound source 21.

[0034] The sound source 21 of the calibration device 100 of the present application generates underwater shock waves, and the center points of the first fixed part and the second fixed part are horizontally aligned with the sound center of the sound source 21. This arrangement makes the directions and sizes of the sound waves received by the standard sensor 32 located at the first fixed part and the sensor to be calibrated 4 located at the second fixed part as similar as possible, thereby reducing the decrease in calibration accuracy caused by inconsistent received sound waves. In addition, the sound source 21 can generate multiple sound waves, so compared with the way explosives generate sound waves, the sound source 21 of the present application effectively reduces the cost of the calibration device 100, and the safety performance can also be improved.

[0035] In some embodiments, the generator 2 further includes a rotating fixture 22. The rotating fixture 22 includes a rotating portion. The sound source 21 is fixed to the rotating portion. The rotating portion extends in a vertical direction Z and can rotate around a vertically extending rotating shaft. By providing the rotating fixture 22, the propagation direction of sound waves of the sound source 21 can be adjusted by the rotating fixture 22. Since the acoustic center of the sound source 21 is in a horizontal position relationship with the first fixed portion and the second fixed portion, the rotating portion is configured to rotate around the vertical direction Z, and can adjust only its propagation direction without changing the position of the acoustic center of the sound source 21 in the vertical direction Z. After the calibration device 100 has been used for many times, the user can adjust the rotating fixture 22 to adjust the direction of generation of the sound wave, thereby ensuring the calibration accuracy of the calibration device 100.

[0036] The rotating fixture 22 may be Figure 1 As shown, the whole is rotatable, that is, the rotating fixture 22 as a whole is a rotating part extending along the vertical direction Z. This arrangement can improve the rigidity of the rotating fixture 22 as a whole. In other embodiments, in order to enable the rotating fixture 22 to adapt to the installation space of the calibration device 100, the rotating fixture 22 may have a non-rotatable fixed part, and the rotating part and the fixed part are rotatably connected. The fixed part can be configured not to extend along the vertical direction Z. In this way, the fixed part can be adjusted according to the routing of the calibration device 100 and the layout position of the components, so as to achieve the avoidance of the components.

[0037] The rotating fixture 22 can be made of a high-rigidity material. The high-rigidity rotating fixture 22 is helpful to ensure the verticality of the sound source 21, and prevent the rotating fixture 22 from shaking when the sound wave is generated, which causes the direction of the sound axis to deviate. The high-rigidity material can be, for example, aluminum alloy, steel, etc. In addition, the connection between the sound source 21 and the rotating part can be achieved by a fixed connection method such as bonding and welding, or a detachable connection by means of threads, buckles, etc.

[0038] The sound source 21 may be, for example, one that generates parallel shock waves, such as a plurality of sound wave generating units that are distributed in parallel. Alternatively, in an optional embodiment, the sound source 21 generates a spherical shock wave, and the fixing fixture 31 extends in the vertical direction Z. Since the centers of the first fixing portion and the second fixing portion are horizontally aligned with the acoustic center of the sound source 21, and the fixing fixture 31 extends in the vertical direction Z, the error in the size of the sound waves generated by the sound source 21 received by the standard sensor 32 and the sensor to be calibrated 4 is smaller, which is beneficial to improving the calibration accuracy of the calibration device 100. In addition, the fixing fixture 31 extends in the vertical direction Z, so it can be fixed, for example, at the upper cover 13. Compared with other directions tangential to the spherical shock wave, this arrangement makes it convenient for personnel to remove the fixing fixture 31 and fix the sensor to be calibrated 4 on the second fixing portion, or remove the sensor to be calibrated 4 from the second fixing portion, without having to put their hands into the liquid.

[0039] Sound waves will increase the background noise of the underwater environment, thereby masking the detection signals of the standard sensor 32 and the sensor to be calibrated 4. Therefore, in an optional embodiment, the container 1 also includes a silencer 12 arranged on the wall of the cavity 11. The silencer 12 can consume the sound waves reaching the wall of the cavity 11, thereby reducing the energy of the sound waves. The silencer 12 can be a sound-absorbing material arranged on the wall of the cavity 11, such as sound-absorbing foam. Alternatively, the silencer 12 can also be a groove structure etched on the wall of the cavity 11, which reduces the propagation of sound waves through a specific shape. Alternatively, the silencer 12 can also be a sound wave absorber for absorbing underwater sound waves. This application is not limited to this.

[0040] like Figure 1 As shown, in order to optimize the sound-absorbing effect of the container 1, each wall surface of the container 1 is provided with a sound-absorbing part 12. However, this should be taken as an example and not a limitation. In other embodiments, the container 1 may have a sound-absorbing part 12 on only part of the wall surface. For example, the upper cover 13 is not provided with a sound-absorbing part 12. Moreover, the arrangement of the sound-absorbing part 12 on different wall surfaces of the container 1 may also be different. This application is not limited to this.

[0041] In one embodiment, the generator 2 includes a plasma sound source control system 24 connected to the sound source 21. The plasma sound source control system 24 is used to control the sound source 21 to release shock waves. The plasma sound source control system 24 can control the information of the sound source 21 such as the maximum charging voltage and the storage capacitor to control the discharge of the sound source 21, thereby achieving the release of a specific underwater shock wave. The plasma sound source control system 24 can very accurately control the frequency, amplitude and phase of the sound waves generated by the sound source 21, thereby improving the calibration accuracy of the calibration device 100.

[0042] In one embodiment, the generator 2 includes a voltage and current sampler 25 connected to the sound source 21. The voltage and current sampler 25 is used to monitor the voltage and current of the sound source 21 to ensure the accuracy of the energy released by the underwater shock wave. In an embodiment where the generator 2 includes both the plasma sound source control system 24 and the voltage and current sampler 25, the calibration device 100 controls the frequency and amplitude of the underwater shock wave signal emission through the signal generator 232, uses the plasma sound source control system 24 to process the pulse signal and transmit it to the sound source 21 for energy release to generate a strong pulse sound wave, forming a supersonic shock wave to propagate outward, and uses the voltage and current sampler 25 to monitor the input current and voltage of the sound source 21 to ensure the accuracy of the charging or discharging parameters of the underwater sound source 21.

[0043] In one embodiment, the receiver 3 includes an electrically connected measuring amplifier 33 and a collector 34. The measuring amplifier 33 is used to obtain and amplify the signals of the standard sensor 32 and the sensor to be calibrated 4, and transmit them to the collector 34. The measuring amplifier 33 can amplify weak acoustic signals so that the acoustic signals can be better detected by the collector 34. At the same time, the amplified signal is easier to be accurately measured, so that the controller 5 can more easily distinguish between signals and noise, thereby improving the calculation accuracy and calibration accuracy of the calibration device 100. Furthermore, the measuring amplifier 33 can be selected with an operating bandwidth of more than 500kHz. The collector 34 can be selected with a sampling rate of more than 60MHz.

[0044] In an optional embodiment, the generator 2 includes a plasma sound source control system 24 and a voltage and current sampler 25. The receiver 3 includes an electrically connected measuring amplifier 33 and a collector 34. The calibration device 100 also includes a controller 5. The controller 5 is electrically connected to the generator 2 and the receiver 3. The calibration device 100 of this embodiment effectively integrates the cutting-edge technology of plasma acoustics and impact dynamics, and aims to realize the calibration of the dynamic performance of underwater shock wave sensors in a low background noise environment. The system integrates a signal generator 232, a voltage and current sampler 25, a measuring amplifier 33, a collector 34 and a powerful data processing controller 5, and together constructs an accurate and comprehensive calibration platform. Its core highlight is that the high-intensity shock wave generated by the plasma sound source 21 is used as a calibration signal, which is carried out in an anechoic water tank, which greatly improves the accuracy and safety of the calibration. Compared with the traditional shock tube calibration method that relies on TNT explosives, it significantly reduces safety hazards and the instability of the results. This innovative technology provides strong support for sensor measurement and performance assurance in many fields such as military equipment detection, marine science and technology research, and marine resource exploration in my country.

[0045] Continue to refer Figure 1 In an optional embodiment, the distance L1 between the standard sensor 32 and the sound source 21 in the horizontal direction X is greater than or equal to 50 cm and less than or equal to 75 cm. The distance L1 is actually calculated based on the discharge gap of the sound source 21. There is an interval between each shock wave emission of the sound source 21 and the previous shock wave emission. This interval is the discharge gap. The discharge gap of the sound source 21 is usually less than 5 cm. Within the range of the distance L1, the stability of underwater shock wave propagation can be guaranteed, thereby reducing the error of the sound waves received by the standard sensor 32 and the sensor 4 to be calibrated, and improving the calibration accuracy and quality of the calibration device 100.

[0046] If the distance between the sound source 21 and the liquid surface is too close, cavitation may occur at the moment of discharge. Cavitation means that the impact energy is too large, causing the liquid to vaporize into air. Cavitation will hinder the further propagation of the shock wave, resulting in the failure of the acoustic energy to be emitted, causing the calibration result to be inaccurate. Therefore, in some embodiments, the distance between the sound source 21 and the liquid surface is greater than or equal to 5 cm and less than or equal to 15 cm. It is understandable that if the distance between the sound source 21 and the liquid surface is too close, cavitation will occur. If the distance from the liquid surface is too far, the volume of the calibration device 100 in the vertical direction Z will be too large. Therefore, this distance range can control the volume of the calibration device 100 while avoiding cavitation.

[0047] In an optional embodiment, the distance D1 between the first fixing portion and the second fixing portion is greater than or equal to 5 cm and less than or equal to 10 cm. The distance D1 can be the farthest distance between the first fixing portion and the second fixing portion, or the shortest distance between the first fixing portion and the second fixing portion, or the center distance between the first fixing portion and the second fixing portion. The range of the distance D1 is to ensure that the center distance between the standard sensor 32 assembled on the first fixing portion and the second fixing portion and the sensor 4 to be calibrated maintains a certain distance, otherwise the two will affect each other. If the distance between the two is too large, the accuracy is poor. Therefore, the range of the distance D1 can ensure that the two are relatively close.

[0048] The calibration principle of the calibration device 100 is as follows:

[0049] t r =t 稳定值的100％ -t 初始

[0050]

[0051] P 标准 =U 标准 S p标准

[0052] ΔP=|P 标准 -P 被校 |

[0053] In the formula,

[0054] t r is the rise time of the sensor 4 to be calibrated,

[0055] t 稳定值的100％ is the moment when the sensor 4 to be calibrated rises to the final value,

[0056] t 初始 is the moment when the response is zero (i.e. the moment when the pressure curve starts to rise),

[0057] S pDynamic sensitivity

[0058] U is the output voltage of the sensor to be calibrated,

[0059] P 标准 is the pressure value output by the standard sensor 32,

[0060] U 标准 is the voltage output by the standard sensor 32,

[0061] P 被校 is the pressure value output by the sensor 4 to be calibrated.

[0062] After obtaining the pressure difference between the sensor to be calibrated 4 and the standard sensor 32, the pressure difference can be used as a correction value. When the sensor to be calibrated 4 is used to measure shock waves, a negative pressure difference needs to be added to each test structure, so that the most realistic shock wave measurement result can be obtained.

[0063] The frequency domain dynamic characteristics of the standard sensor 32 are:

[0064]

[0065] The frequency domain dynamic characteristics of the sensor 4 to be calibrated are:

[0066]

[0067] The calibration device 100 further includes a controller 5. The controller 5 is used to obtain the signal response of the standard sensor 32 and the signal response of the sensor to be calibrated 4, and obtain the passband frequency according to the following formula:

[0068]

[0069] in,

[0070] H1(jω) is the frequency domain dynamic characteristic of the standard sensor 32,

[0071] H2(jω) is the frequency domain dynamic characteristic of the sensor 4 to be calibrated,

[0072] F[~] is Fourier transform,

[0073] p1(t) is the signal response of the standard sensor 32,

[0074] p2(t) is the signal response of the sensor 4 to be calibrated,

[0075] y1(t) is the shock wave signal response generated by the sound source 21.

[0076] By acquiring the signal response of the standard sensor 32 and the signal response of the sensor 4 to be calibrated, performing Fourier transform on the two and dividing them, the passband frequency can be obtained. By acquiring the frequency domain dynamic characteristic index of the standard sensor 32 and calculating it with the passband frequency, the true frequency domain dynamic characteristic of the sensor 4 to be calibrated can be obtained without acquiring the shock wave signal response generated by the sound source 21.

[0077] It should be noted that the technical solutions or technical features described in the above embodiments can be combined or supplemented with each other without causing conflicts. The scope of protection of this application is not limited to the precise structures described in the above embodiments and shown in the drawings; all modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this application should be included in the scope of protection of this application.

Claims

1. A calibration device, characterized in that: include: A container, comprising a cavity for containing a liquid; A generator, including a sound source located in the cavity; The sound source is used to generate underwater shock waves in the liquid; as well as A receiver, comprising a fixing fixture and a standard sensor located in the cavity; the standard sensor is used to receive the underwater shock wave in the liquid; the fixing fixture comprises a first fixing part and a second fixing part located in the cavity; the standard sensor is connected to the first fixing part; the second fixing part is used to connect to a sensor to be calibrated placed in the liquid; Wherein, the center points of the first fixing portion and the second fixing portion are horizontally aligned with the sound center of the sound source.

2. The calibration device according to claim 1, characterized in that: The generator further comprises a rotating fixture; the rotating fixture comprises a rotating part; the sound source is fixed to the rotating part; the rotating part extends in a vertical direction and can rotate around a vertically extending rotating shaft.

3. The calibration device according to claim 1 or 2, characterized in that: The sound source is used to generate underwater spherical shock waves; and the fixing fixture extends in a vertical direction.

4. The calibration device according to claim 3, characterized in that: The distance between the standard sensor and the sound source in the horizontal direction is greater than or equal to 50 centimeters and less than or equal to 75 centimeters.

5. The calibration device according to claim 1, characterized in that: A distance between the first fixing portion and the second fixing portion is greater than or equal to 5 centimeters and less than or equal to 10 centimeters.

6. The calibration device according to claim 1, characterized in that: The distance between the sound source and the liquid surface of the liquid is greater than or equal to 5 centimeters and less than or equal to 15 centimeters.

7. The calibration device according to claim 1, characterized in that: The container further comprises a muffler arranged on the wall surface of the cavity.

8. The calibration device according to claim 1, characterized in that: The generator comprises a plasma sound source control system connected to the sound source, for controlling the sound source to release shock waves; and / or, The generator includes a voltage and current sampler connected to the sound source, and is used to monitor the voltage and current of the sound source.

9. The calibration device according to claim 1, characterized in that: The receiver includes a measuring amplifier and a collecting instrument which are electrically connected; the measuring amplifier is used to obtain and amplify the signals of the standard sensor and the sensor to be calibrated, and transmit them to the collecting instrument.

10. The calibration device according to claim 1, characterized in that: The calibration device further includes a controller; the controller is used to obtain the signal response of the standard sensor and the signal response of the sensor to be calibrated, and obtain the passband frequency according to the following formula: Among them, H1(jω) is the frequency domain dynamic characteristic of the standard sensor, H2(jω) is the frequency domain dynamic characteristic of the sensor to be calibrated, F[~] is Fourier transform, p1(t) is the signal response of the standard sensor, and p2(t) is the signal response of the sensor to be calibrated.

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