Non-contact ultrasonic multifunctional measurement device and method for strong vibration applications

Abstract

The present invention relates to a non-contact ultrasonic multifunctional measurement device and method for strong vibration applications, the method comprising: obtaining downstream signals and upstream signals; respectively calculating the downstream phase difference and the upstream phase difference of the downstream signal and the upstream signal; respectively calculating the downstream delay time and the upstream delay time of the downstream signal and the upstream signal; respectively calculating the downstream and upstream phases according to the downstream phase difference, the upstream phase difference and the downstream delay time and the upstream delay time; and calculating the volume flow to be measured according to the downstream phase and the upstream phase. The present invention can accurately obtain high-precision time delay and phase measurement data in a strong vibration environment, and then accurately measure the volume flow under the Doppler frequency shift phenomenon; and the present invention effectively combines the advantages of pulse waves and continuous waves, and can complete the flow measurement by transmitting a signal once.

Description

Technical Field

[0001] The present invention relates to the field of ultrasonic measurement technology, and in particular to a non-contact ultrasonic multifunctional measurement device and method for strong vibration applications. Background Art

[0002] At present, the measurement methods of ultrasonic flow meters mainly include:

[0003] 1) Doppler shift technology

[0004] Doppler shift refers to the change in phase and frequency caused by the difference in propagation distance when the mobile station moves in a certain direction at a constant speed. The measurement principle of ultrasonic Doppler flowmeter is based on Doppler shift. In the ultrasonic Doppler flow measurement method, the ultrasonic transmitter is a fixed sound source, and the solid particles moving with the fluid act as "observers" with relative motion to the sound source. The frequency difference between the transmitted sound wave and the received sound wave is the Doppler shift of the sound wave caused by the movement of solid particles in the fluid. Since this frequency difference is proportional to the fluid flow velocity, the flow velocity can be obtained by measuring the frequency difference, and then the flow rate of the fluid can be obtained.

[0005] For example, patent application CN111337093A discloses an ultrasonic flow measurement method and device. The method is based on the pulse Doppler principle, utilizes the difference in Doppler frequency shift and amplitude of the echo signal between the gas and liquid phases, extracts the Doppler signal in the echo signal through the orthogonal demodulation method, and uses short-time Fourier transform to draw a time-frequency spectrum diagram. The bubble size in the measurement channel is then judged through the time-frequency spectrum diagram, thereby identifying the flow type of the fluid in the pipeline.

[0006] However, the existing ultrasonic Doppler flow measurement method also has certain defects. For example, it requires that the measured system (such as the fluid in the pipeline) should have a certain number of solid particles or bubbles that can reflect sound waves, so its application scenarios are very limited.

[0007] 2) Use single frequency sound waves for flow measurement

[0008] Patent application CN111337093A also discloses an ultrasonic flow measurement method and device, which calculates the overall flow rate by calculating the overall phase of the downstream and upstream flow, respectively. However, this method does not take into account the measurement error in a high-intensity vibration environment (or motion system).

[0009] Therefore, there is an urgent need for a method that can accurately measure the flow volume in a moving system. Summary of the invention

[0010] The purpose of the present invention is to provide a non-contact ultrasonic multifunctional measurement device and method for strong vibration applications, which partially solves or alleviates the above-mentioned deficiencies in the prior art and can accurately measure the flow rate of the oil supply pipeline in a strong vibration environment such as caused by engine operation. In addition, the present invention combines the advantages of pulse waves and continuous waves, and only needs to transmit a signal once to complete the flow measurement.

[0011] In order to solve the above-mentioned technical problems, the present invention specifically adopts the following technical solutions:

[0012] A first aspect of the present invention is to provide a non-contact ultrasonic measurement method for strong vibration applications, comprising the steps of:

[0013] S101: Acquire a downstream signal and an upstream signal, wherein the downstream signal includes: a first transmission signal and a first reception signal corresponding thereto, and the upstream signal includes: a second transmission signal and a second reception signal corresponding thereto;

[0014] S102 calculates the downstream phase difference and the upstream phase difference between the transmitted signal and the corresponding received signal in the downstream signal and the upstream signal respectively;

[0015] S103 calculates the downstream delay time and the upstream delay time of the downstream signal and the upstream signal respectively; wherein S103 includes the steps of:

[0016] S31 performs Fourier transform on the received signal and the transmitted signal respectively to obtain a first Fourier transform complex value and a second Fourier transform complex value correspondingly;

[0017] S32 performs conjugate point multiplication on the first Fourier transform complex value and the second Fourier transform complex value to obtain a third Fourier transform complex value;

[0018] S33 reads a corresponding delay time according to the third Fourier transform complex value, wherein the delay time is a position point corresponding to the maximum peak point in the corresponding Fourier transform complex value;

[0019] S104 uses a phase calculation model to calculate the downstream phase and the upstream phase according to the downstream phase difference, the upstream phase difference, the downstream delay time, and the downstream delay time;

[0020] S105 calculates the volume flow to be measured according to the phase of the downstream flow and the phase of the upstream flow.

[0021] In some embodiments, before S101, the method further includes:

[0022] sending a transmit signal at a first frequency;

[0023] receiving a received signal corresponding to the transmitted signal;

[0024] Determine whether the signal strength of the received signal falls within a first strength threshold range; if so, determine the second frequency according to a first selection rule, where the first selection rule requires that the second frequency be greater than or equal to the first frequency; correspondingly, send the corresponding first or second transmission signal at the second frequency in S101.

[0025] In some embodiments, the number of cycles of the transmitted signal satisfies a second selection rule, and the second selection rule is:

[0026]

[0027] In some embodiments, before S101, the method further includes:

[0028] Sending a transmission signal, wherein the number of cycles of the transmission signal is a first set value;

[0029] receiving a received signal corresponding to the transmitted signal;

[0030] Determine whether the difference between the frequency of the received signal and the frequency of the transmitted signal falls within a preset frequency difference range. If so, select the number of cycles of the transmitted signal according to a third selection rule, wherein the third selection rule is: the number of cycles of the transmitted signal ≥ the first set value.

[0031] In some embodiments, S102 includes the steps of:

[0032] S21 performs Fourier transform on the transmission signal to obtain a first Fourier transform complex value, and finds the amplitude |F 发射 |The maximum value and the corresponding frequency position;

[0033] S22 performs Fourier transform on the received signal to obtain a second Fourier transform complex value, and obtains a corresponding Fourier transform complex value at the frequency position obtained in S21 in the second Fourier transform complex value;

[0034] S23, at the frequency position, using the real part and the imaginary part of the Fourier transform complex value corresponding to the first Fourier transform complex value at the frequency position to calculate the phase value of the transmitted signal, and using the real part and the imaginary part of the Fourier transform complex value corresponding to the second Fourier transform complex value at the same frequency position to calculate the phase value of the received signal;

[0035] S24 calculates a corresponding phase difference according to the phase value of the transmitted signal and the phase value of the received signal.

[0036] In some embodiments, S33 includes the steps of:

[0037] Determining whether the signal strength in the third Fourier transform complex value belongs to a second strength threshold range;

[0038] If yes, then execute the steps:

[0039] Using a frequency domain low-pass filtering method to filter the third Fourier transform complex value, and correspondingly obtain a fourth Fourier transform complex value;

[0040] Find the maximum peak point in the fourth Fourier transform complex value, and use the position point corresponding to the maximum peak point as the delay time;

[0041] If not, then perform the following steps:

[0042] Performing an inverse Fourier transform on the third Fourier transform complex value to obtain a fifth Fourier transform complex value;

[0043] Squaring the fifth Fourier transform complex value, and performing Fourier transform on the squared fifth Fourier transform complex value to obtain a sixth Fourier transform complex value;

[0044] The sixth Fourier transform complex value is filtered by using a frequency domain low-pass filtering method, and the seventh Fourier transform complex value is obtained by using an inverse Fourier transform again;

[0045] The maximum peak point in the seventh Fourier transform complex value is found, and the position point corresponding to the maximum peak point is used as the delay time.

[0046] In some embodiments, the phase calculation model includes:

[0047]

[0048]

[0049] Among them, Int represents the phase ambiguity number, τ0 represents the delay time, and f represents the signal frequency. represents the phase difference, and φ represents the phase.

[0050] In some embodiments, the calculation model of the volume flow in S105 is:

[0051]

[0052] Among them, Q V represents the volume flow rate, R represents the pipe radius, represents the speed of sound wave propagation in solids, φ u represents the phase of the countercurrent, φ drepresents the downstream phase, and θ1 represents the angle between the normal direction of the ultrasonic transducer and the normal direction of the pipe wall.

[0053] The second aspect of the present invention also provides a non-contact ultrasonic measuring device for strong vibration applications, comprising:

[0054] A signal acquisition module is configured to acquire a downstream signal and an upstream signal, wherein the downstream signal includes: a first transmission signal and a first reception signal corresponding thereto, and the upstream signal includes: a second transmission signal and a second reception signal corresponding thereto;

[0055] A phase difference calculation module is configured to calculate the downstream phase difference and the upstream phase difference between the transmitted signal and the corresponding received signal in the downstream signal and the upstream signal respectively;

[0056] The delay time calculation module is configured to respectively calculate the downstream delay time and the upstream delay time of the downstream signal and the upstream signal; wherein the delay time calculation module includes:

[0057] A first transform unit is configured to perform Fourier transform on the received signal and the transmitted signal respectively, so as to obtain a first Fourier transform complex value and a second Fourier transform complex value correspondingly;

[0058] a conjugate point multiplication unit configured to perform conjugate point multiplication on the first Fourier transform complex value and the second Fourier transform complex value to obtain a third Fourier transform complex value;

[0059] A delay time calculation unit is configured to read a corresponding delay time according to the third Fourier transform complex value, wherein the delay time is a position point corresponding to a maximum peak point in the corresponding Fourier transform complex value;

[0060] A phase calculation module is configured to respectively calculate the downstream phase and the upstream phase according to the downstream phase difference, the upstream phase difference, the downstream delay time and the upstream delay time using a phase calculation model;

[0061] The volume flow calculation module is configured to calculate the volume flow to be measured according to the phase of the downstream flow and the phase of the upstream flow.

[0062] In some embodiments, it also includes:

[0063] The pre-transmission module is configured to send a transmission signal at a first frequency; receive a reception signal corresponding to the transmission signal; determine whether the signal strength of the reception signal belongs to a first strength threshold range, and if so, determine a second frequency according to a first selection rule, wherein the first selection rule requires that the second frequency is greater than or equal to the first frequency; correspondingly, send the corresponding first or second transmission signal at the second frequency.

[0064] Beneficial technical effects:

[0065] In order to address the measurement error problem caused by the vibration of pipelines and ultrasonic probes in a strong vibration environment, the present invention proposes, on the one hand, a restrictive emission mode to improve the measurement accuracy of a method for measuring fluid volume based on time delay and phase difference; on the other hand, a new time delay and phase difference calculation method is proposed to further alleviate the measurement error in a strong vibration environment.

[0066] Specifically, the present invention proposes a restrictive transmission mode, which can limit key characteristics such as the number of transmission signal cycles and frequency (for example, an appropriate transmission signal can be selected through a pre-test method), thereby ensuring that the ultrasonic probe can work stably at the excitation frequency, and further ensuring the accuracy of subsequent signal acquisition, delay and phase calculation.

[0067] Furthermore, the new delay calculation method proposed in the present invention utilizes a collaborative processing method combining strength verification with multi-level Fourier transform, and can calculate high-precision delay information based on environmental characteristics under different vibration environments and signal transmission conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, each element or part is not necessarily drawn according to the actual scale. Obviously, the drawings described below are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without paying creative labor.

[0069] Figure 1 is a flow chart of a measuring method in an exemplary embodiment of the present invention;

[0070] Figure 2 This is a schematic diagram of the basic principle of flow meter measurement;

[0071] Figure 3 It is a schematic diagram of the module structure of a measurement system in an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0072] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 making creative work are within the scope of protection of the present invention.

[0073] Herein, suffixes such as "module", "component" or "unit" used to represent elements are only used to facilitate the description of the present invention, and have no specific meanings by themselves. Therefore, "module", "component" or "unit" can be used mixedly.

[0074] In this document, the terms "upper", "lower", "inner", "outer", "front", "back", "one end", "the other end" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0075] In this document, unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0076] Herein "and / or" includes any and all combinations of one or more of the associated listed items.

[0077] Herein, "plurality" means two or more than two, ie, it includes two, three, four, five, etc.

[0078] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0079] As used in this specification, the term "about" typically means + / - 5% of the stated value, more typically + / - 4% of the stated value, more typically + / - 3% of the stated value, more typically + / - 2% of the stated value, even more typically + / - 1% of the stated value, and even more typically + / - 0.5% of the stated value.

[0080] In this specification, some embodiments may be disclosed in a format of being within a certain range. It should be understood that such description of "being within a certain range" is only for convenience and brevity, and should not be interpreted as a rigid limitation on the disclosed range. Therefore, the description of the range should be considered to have specifically disclosed all possible sub-ranges and independent numerical values ​​within this range. For example, the range The description of should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within this range, for example, 1, 2, 3, 4, 5, and 6. The above rules apply regardless of the breadth of the range.

[0081] The operation of engines of manned lunar exploration, rockets, hypersonic vehicles and other aircraft brings strong vibration and noise, causing significant vibration in the engine fuel supply pipeline, which will have a serious impact on the ultrasonic propagation characteristics in the fuel supply pipeline (for example, the applicant found that the strong vibration will turn the ultrasonic transducer into a moving sound source), thereby producing phenomena such as non-negligible Doppler frequency shift, which seriously reduces the flow, bubble and cumulative measurement based on ultrasonic technology.

[0082] However, the existing ultrasonic measurement methods only consider the characteristic changes of sound waves during their movement, while ignoring the impact of the movement of the sound source on the final measurement results. Especially for flow measurement in strong vibration scenarios, the measurement error caused by the vibration of the sound source is very large.

[0083] For example, the applicant found that if the ultrasonic flowmeter is operated at the fuel supply line of the engine, in a strong vibration environment such as caused by the operation of the engine, the ultrasonic flowmeter vibrates along with the vibration of the pipe wall. When the ultrasonic flowmeter is used as the transmitting sound source, the vibrating ultrasonic flowmeter becomes a moving sound source, and Doppler frequency shift occurs. This is inconsistent with the assumption of the Doppler flowmeter (i.e., using ultrasonic waves as a fixed sound source). Therefore, there are unavoidable errors in the measurement accuracy during its actual application.

[0084] Moreover, due to the technical limitations of data acquisition chips, the data acquisition error in actual applications is also very high, making it difficult to meet the needs of high-precision time measurement.

[0085] For example, for aerospace propulsion systems, nitrogen tetroxide is often used as an oxidant. At room temperature of 20°C, the propagation speed of sound waves in liquid nitrogen tetroxide is 1013m / s, and the propagation speed of sound waves in titanium alloy is 5160m / s. Methyl hydrazine is often used as a fuel. At room temperature of 20°C, the propagation speed of sound waves in methyl hydrazine is about 1444m / s.

[0086] According to the measurement error requirement of 0.15%, the measurement time and phase errors can be calculated. Table 1 lists the maximum time measurement and phase measurement errors corresponding to the instantaneous flow measurement accuracy of 0.15% under different flow rates and ultrasonic pipe factory configurations.

[0087] Table 1. Performance corresponding to the working conditions (measurement error 0.15%)

[0088]

[0089] As can be seen from Table 1, to ensure that the flow measurement error is 0.15%, when the measuring tube length is 0.15m, the phase measurement error needs to be less than 1.36°, and the time measurement error needs to meet 0.75ns; when the measuring tube length is 0.3m, the phase measurement error is less than 2.71° to meet the requirements, and the time measurement error needs to meet 1.506ns. It is not difficult to see that in order to obtain high-precision measurement performance, the time measurement error often needs to be above ns. However, due to industrial requirements, the currently applicable digital-analog acquisition chip has a sampling rate of 100Mbps and a time resolution of 10ns, which makes it difficult to achieve high-precision time measurement.

[0090] Therefore, in order to break through the existing hardware and software technical limitations and accurately measure the flow rate of the fuel supply pipeline of a high-speed aircraft when the engine is working, the present invention proposes a high-precision flow rate calculation method achieved by a restrictive emission mode.

[0091] Embodiment 1

[0092] See also Figure 1 As shown, the present invention provides a non-contact ultrasonic measurement method for strong vibration applications, comprising the steps of:

[0093] S101: Acquire a downstream signal and an upstream signal, wherein the downstream signal includes: a first transmission signal and a first reception signal corresponding thereto, and the upstream signal includes: a second transmission signal and a second reception signal corresponding thereto;

[0094] In some embodiments, the same number of data points are collected for the transmitted signal and the received signal.

[0095] S102 calculates the downstream phase difference and the upstream phase difference between the transmitted signal and the corresponding received signal in the downstream signal and the upstream signal respectively;

[0096] S103 calculates the downstream delay time and the downstream delay time of the downstream signal and the upstream signal respectively;

[0097] S104 uses a phase calculation model to calculate the downstream phase and the upstream phase according to the downstream phase difference, the upstream phase difference, the downstream delay time, and the upstream delay time; wherein the phase calculation model includes:

[0098]

[0099]

[0100] Among them, Int represents the phase ambiguity number, τ0 represents the delay time, and f represents the signal frequency. represents the phase difference, and φ represents the phase.

[0101] S105 calculates the volume flow to be measured according to the phase of the downstream flow and the phase of the upstream flow. The calculation model of the volume flow is:

[0102]

[0103] Among them, Q V represents the volume flow rate, R represents the pipe radius, represents the speed of sound wave propagation in solids, φ u represents the phase of the countercurrent, φ d represents the downstream phase, θ1 represents the angle between the normal direction of the ultrasonic transducer (or ultrasonic probe) and the normal direction of the pipe wall (e.g. Figure 2 shown).

[0104] Ultrasonic measurement principle Figure 2 As shown in the figure, the piezoelectric ceramic in the ultrasonic probe (mainly including piezoelectric ceramic sheets and acoustic wedges) is connected to the pipe wall through the acoustic wedge, and the sound wave propagation path can be extended by changing the position of the acoustic wedge. The angle between the normal direction of the ultrasonic transducer and the normal direction of the pipe wall is θ1, and the thickness of the pipe wall is h w , the distance between the sound wedges is L, and the ultrasonic transducer is on the plane of the pipe axis. The measured pipe radius is R, and the measured pipe radius is R. Considering that the pipe wall and the ultrasonic sound wedge are made of the same material, the ultrasonic wave propagates at the same speed in the sound wedge and the pipe wall, and there is no angle change. If, on the inner wall of the pipe, the sound wave propagation speed is inconsistent in different media, resulting in a refraction angle θ2. Among them, it can be assumed that the fluid flow field is a uniform flow field (v).

[0105] In a strong vibration environment, the Doppler frequency shift phenomenon in the signal acquisition data is very obvious, but the traditional phase difference calculation method is difficult to eliminate the influence of the Doppler frequency shift. Therefore, the present invention proposes a phase difference solution method for performing correlation calculation on the transmitted signal and the received signal for phase difference measurement in a strong vibration environment. By performing correlation calculation on the transmitted signal and the received signal, the influence of the Doppler frequency shift on the final flow measurement result can be eliminated.

[0106] For example, in some embodiments, S102 includes the steps of:

[0107] S21 performs Fourier transform on the transmission signal to obtain a first Fourier transform complex value, and finds the amplitude |F 发射 |The maximum value and the corresponding frequency position;

[0108] S22 performs Fourier transform on the received signal to obtain a second Fourier transform complex value, and obtains a corresponding Fourier transform complex value at the frequency position obtained in S21 in the second Fourier transform complex value;

[0109] S23, at the frequency position, using the real part and the imaginary part of the Fourier transform complex value corresponding to the first Fourier transform complex value at the frequency position to calculate the phase value of the transmitted signal, and using the real part and the imaginary part of the Fourier transform complex value corresponding to the second Fourier transform complex value at the same frequency position to calculate the phase value of the received signal;

[0110] S24 calculates a corresponding phase difference according to the phase value of the transmitted signal and the phase value of the received signal.

[0111] For example, in some embodiments, the first transmission signal is first subjected to a Fourier transform, and the Fourier transform amplitude F of the first transmission signal is found. 发射 | maximum value and the corresponding frequency position. At the same time, the first received signal is subjected to a corresponding Fourier transform to obtain F 接收 , find the Fourier transform value of the first received signal at the frequency position of the maximum amplitude point of the first transmitted signal, and use the real and imaginary parts of the Fourier transform at the same frequency position to obtain the phase value of the first transmitted signal and the first received signal, that is, φ = atan (F imag / F real ), then the phase delay (i.e., phase difference) can be obtained by subtracting the phase of the first transmitted signal from the phase of the first received signal, ▽φ=φ 接收 -φ 发射 .

[0112] In this embodiment, the signal phase is calculated according to the co-frequency position of the transmitted signal and the received signal, which can effectively alleviate the signal detection error generated in a high-intensity vibration environment.

[0113] In addition, traditional delay algorithms usually use time domain convolution methods, but the amount of data calculation in the time domain convolution method is very high and the hardware consumption is large. In this regard, this application proposes a frequency domain product calculation method based on multi-level evaluation to reduce the amount of calculation and hardware consumption while improving the calculation reliability.

[0114] For example, in some embodiments, S103 includes the steps of:

[0115] S31 performs Fourier transform on the received signal and the transmitted signal respectively to obtain a first Fourier transform complex value and a second Fourier transform complex value correspondingly;

[0116] S32 performs conjugate point multiplication on the first Fourier transform complex value and the second Fourier transform complex value to obtain a third Fourier transform complex value;

[0117] S33 reads a corresponding delay time according to the third Fourier transform complex value, where the delay time is a position point corresponding to the maximum peak point in the corresponding Fourier transform complex value.

[0118] In some embodiments, S33 includes the steps of:

[0119] Determine whether the signal strength in the third Fourier transform complex value belongs to a second strength threshold range; for example, determine whether the signal strength is greater than or equal to 10 dBm.

[0120] If yes, then execute the steps:

[0121] Using a frequency domain low-pass filtering method to filter the third Fourier transform complex value, and correspondingly obtain a fourth Fourier transform complex value;

[0122] Find the maximum peak point in the fourth Fourier transform complex value, and use the position point corresponding to the maximum peak point as the delay time;

[0123] If not, then perform the following steps:

[0124] Performing an inverse Fourier transform on the third Fourier transform complex value to obtain a fifth Fourier transform complex value;

[0125] Squaring the fifth Fourier transform complex value, and performing Fourier transform on the squared fifth Fourier transform complex value to obtain a sixth Fourier transform complex value;

[0126] The sixth Fourier transform complex value is filtered by using a frequency domain low-pass filtering method, and the seventh Fourier transform complex value is obtained by using an inverse Fourier transform again;

[0127] The maximum peak point in the seventh Fourier transform complex value is found, and the position point corresponding to the maximum peak point is used as the delay time. Furthermore, high-precision delay information of the downstream signal and the upstream signal is calculated by successive Fourier transforms and signal processing cross processing.

[0128] In this embodiment, in order to address the delay measurement error caused by Doppler frequency shift, especially in high-intensity vibration environments, a collaborative processing method based on intensity verification and multi-level Fourier transform is proposed to accurately calculate high-precision delay information for different vibration environments.

[0129] Specifically, for signals of different strengths, different processing methods may be used for the signals to improve the accuracy of subsequent operations.

[0130] Furthermore, the frequency domain product method in this embodiment can implement parallel computing in a field programmable logic device (FPGA), thereby reducing hardware consumption.

[0131] Furthermore, in order to improve the accuracy of flow measurement, the present invention also proposes a restrictive signal transmission method to limit key features such as signal transmission frequency and number of cycles, thereby improving the accuracy and reliability of subsequent data collection and calculation.

[0132] In some embodiments, before S101, the method further includes:

[0133] sending a transmit signal at a first frequency;

[0134] receiving a received signal corresponding to the transmitted signal;

[0135] Determine whether the signal strength of the received signal falls within a first strength threshold range; if so, determine the second frequency according to a first selection rule, where the first selection rule requires that the second frequency be greater than or equal to the first frequency; correspondingly, send the corresponding first or second transmission signal at the second frequency in S101.

[0136] For example, in some embodiments, when applied to the flow measurement of the fuel supply pipeline of the engine, if the signal strength (such as the signal-to-noise ratio) of the received signal is greater than or equal to 10 dBm, the current actual transmission frequency can be used as the minimum transmission frequency in the actual measurement process.

[0137] That is to say, before the flow measurement is performed in this embodiment, the frequency of the transmitted signal can be selected through a pre-test to ensure the accuracy of subsequent signal acquisition and phase and delay calculation.

[0138] Preferably, in some embodiments, ultrasonic waves of one frequency are used as the transmission signal.

[0139] In some embodiments, the number of cycles of the transmitted signal satisfies a second selection rule, and the second selection rule is:

[0140]

[0141] The signal sampling rate (also known as sampling speed or sampling frequency) refers to the number of samples extracted from a continuous signal to form a discrete signal per unit time. The signal sampling length is used to represent the total length of the sample points collected during the sampling process (or the length of the discrete signal obtained by the collection).

[0142] In some embodiments, before S101, the method further includes:

[0143] Sending a transmission signal, wherein the number of cycles of the transmission signal is a first set value;

[0144] receiving a received signal corresponding to the transmitted signal;

[0145] Determine whether the difference between the frequency of the received signal and the frequency of the transmitted signal falls within a preset frequency difference range. If so, select the number of cycles of the transmitted signal according to a third selection rule, wherein the third selection rule is: the number of cycles of the transmitted signal ≥ the first set value.

[0146] For example, in some embodiments, before performing actual flow measurement, the steps include:

[0147] After the actual transmission frequency of the transmission signal (equivalent to the second frequency) is selected, a pulse wave of 30 cycles (equivalent to the first set number) is sent in advance at the selected transmission frequency, and it is determined whether the current received signal is at the same frequency as the transmission signal. If so, the number of cycles of the actual transmission signal can be set to be greater than or equal to 30.

[0148] Different from the traditional Doppler measurement technology, the present invention uses the ultrasonic probe as a moving sound source for measurement, and correspondingly proposes a time delay and phase combination measurement method based on a restrictive excitation mode, so as to obtain the flow in the pipeline in a vibrating state through comprehensive calculation of time delay and phase.

[0149] Specifically, the present invention can limit two characteristics of the transmission signal, such as the number of cycles and the frequency, during the pre-test phase to ensure that the ultrasonic probe can work stably at the excitation frequency and that the ultrasonic wave can ensure the accuracy of subsequent delay and phase calculations.

[0150] For example, in some embodiments, the present invention usually sets the number of cycles to be greater than or equal to 50 through the second and third selection rules to ensure that the transmission signal and the reception signal have the same frequency.

[0151] Embodiment 2

[0152] like Figure 3 As shown, the present invention also provides a non-contact ultrasonic measurement system for strong vibration applications, including:

[0153] The signal acquisition module 10 is configured to acquire a downstream signal and an upstream signal, wherein the downstream signal includes: a first transmission signal and a first reception signal corresponding thereto, and the upstream signal includes: a second transmission signal and a second reception signal corresponding thereto;

[0154] The phase difference calculation module 20 is configured to calculate the downstream phase difference and the upstream phase difference between the transmitted signal and the corresponding received signal in the downstream signal and the upstream signal respectively;

[0155] The delay time calculation module 30 is configured to respectively calculate the downstream delay time and the upstream delay time of the downstream signal and the upstream signal; wherein the delay time calculation module includes:

[0156] The first transform unit 31 is configured to perform Fourier transform on the received signal and the transmitted signal respectively, so as to obtain a first Fourier transform complex value and a second Fourier transform complex value correspondingly;

[0157] A conjugate point multiplication unit 32 is configured to perform conjugate point multiplication on the first Fourier transform complex value and the second Fourier transform complex value to obtain a third Fourier transform complex value;

[0158] The delay time calculation unit 33 is configured to read the corresponding delay time according to the third Fourier transform complex value, wherein the delay time is a position point corresponding to the maximum peak point in the corresponding Fourier transform complex value;

[0159] The phase calculation module 40 is configured to respectively calculate the downstream phase and the upstream phase according to the downstream phase difference, the upstream phase difference, the downstream delay time and the downstream delay time using a phase calculation model;

[0160] The volume flow calculation module 50 is configured to calculate the volume flow to be measured according to the phase of the downstream flow and the phase of the upstream flow.

[0161] In some embodiments, the system further comprises:

[0162] The first pre-transmission module 60 is configured to send a transmission signal at a first frequency; receive a reception signal corresponding to the transmission signal; determine whether the signal strength of the reception signal falls within a first strength threshold range, and if so, determine a second frequency according to a first selection rule, wherein the first selection rule requires that the second frequency is greater than or equal to the first frequency; correspondingly, send the corresponding first or second transmission signal at the second frequency.

[0163] In some embodiments, the number of cycles of the transmitted signal satisfies a second selection rule, and the second selection rule is:

[0164]

[0165] In some embodiments, the system further comprises:

[0166] The second pre-transmission module 70 is configured to send a transmission signal, and the number of cycles of the transmission signal is a first set value; receive a received signal corresponding to the transmission signal; determine whether the difference between the frequency of the received signal and the frequency of the transmission signal belongs to a preset frequency difference range, and if so, select the number of cycles of the transmission signal according to a third selection rule, and the third selection rule is: the number of cycles of the transmission signal ≥ the first set value.

[0167] In some embodiments, the phase difference calculation module includes:

[0168] The transmission signal calculation unit 21 is configured to perform Fourier transform on the transmission signal to obtain a first Fourier transform complex value, and find the amplitude |F 发射 |The maximum value and the corresponding frequency position;

[0169] A received signal calculation unit 22 is configured to perform Fourier transform on the received signal to obtain a second Fourier transform complex value, and obtain a corresponding Fourier transform complex value at a frequency position obtained in the transmitted signal calculation unit in the second Fourier transform complex value;

[0170] The phase value calculation unit 23 is configured to calculate the phase value of the transmitted signal at the frequency position using the real part and the imaginary part of the Fourier transform complex value corresponding to the first Fourier transform complex value at the frequency position, and calculate the phase value of the received signal using the real part and the imaginary part of the Fourier transform complex value corresponding to the second Fourier transform complex value at the same frequency position;

[0171] The phase difference calculation unit 24 is configured to calculate the corresponding phase difference according to the phase value of the transmitted signal and the phase value of the received signal.

[0172] In some embodiments, the delay time calculation unit includes:

[0173] a judgment subunit configured to judge whether the signal strength in the third Fourier transform complex value belongs to the second strength threshold range; if so, start the first delay calculation subunit, which is configured to filter the third Fourier transform complex value by using a frequency domain low-pass filtering method to obtain a fourth Fourier transform complex value accordingly;

[0174] Find the maximum peak point in the fourth Fourier transform complex value, and use the position point corresponding to the maximum peak point as the delay time; if not, start the second delay calculation subunit, which is configured to perform an inverse Fourier transform on the third Fourier transform complex value to obtain a fifth Fourier transform complex value; square the fifth Fourier transform complex value, and perform Fourier transform on the squared fifth Fourier transform complex value to obtain a sixth Fourier transform complex value; use frequency domain low-pass filtering to filter the sixth Fourier transform complex value, and use inverse Fourier transform again to obtain a seventh Fourier transform complex value; find the maximum peak point in the seventh Fourier transform complex value, and use the position point corresponding to the maximum peak point as the delay time.

[0175] Furthermore, compared with the standard sidetone phase measurement method that uses multiple frequency sound waves, the present invention solves the problem of precision measurement by using only one frequency sound wave.

[0176] The present invention combines the advantages of pulse wave and continuous wave. It only needs to send once to solve the problem. The traditional measurement mode needs to send pulse wave first and then send continuous wave, and the operation process is relatively complicated.

[0177] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0178] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for a computer terminal (which can be a mobile phone, a computer, a server, or a network device, etc.) to execute the methods described in each embodiment of the present invention.

[0179] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A non-contact ultrasonic measurement method for strong vibration applications, characterized in that: Includes steps: S101: Acquire a downstream signal and an upstream signal, wherein the downstream signal includes: a first transmission signal and a first reception signal corresponding thereto, and the upstream signal includes: a second transmission signal and a second reception signal corresponding thereto; S102 calculates the downstream phase difference and the upstream phase difference between the transmitted signal and the corresponding received signal in the downstream signal and the upstream signal respectively; S103 calculates the downstream delay time and the upstream delay time of the downstream signal and the upstream signal respectively; wherein S103 includes the steps of: S31 performs Fourier transform on the received signal and the transmitted signal respectively to obtain a first Fourier transform complex value and a second Fourier transform complex value correspondingly; S32 performs conjugate point multiplication on the first Fourier transform complex value and the second Fourier transform complex value to obtain a third Fourier transform complex value; S33 reads a corresponding delay time according to the third Fourier transform complex value, where the delay time is a position point corresponding to the maximum peak point in the corresponding Fourier transform complex value; S104 uses a phase calculation model to calculate the downstream phase and the upstream phase according to the downstream phase difference, the upstream phase difference, the downstream delay time, and the downstream delay time; S105 calculates the volume flow to be measured according to the phase of the downstream flow and the phase of the upstream flow; wherein the phase calculation model includes: （1）； （2）； in, represents the phase ambiguity number, Indicates the delay time. f represents the signal frequency, represents the phase difference, Indicates phase.

2. A non-contact ultrasonic measurement method for strong vibration applications according to claim 1, characterized in that: Prior to S101, it also included: sending a transmit signal at a first frequency; receiving a received signal corresponding to the transmitted signal; Determine whether the signal strength of the received signal falls within a first strength threshold range; if so, determine a second frequency according to a first selection rule, where the first selection rule requires that the second frequency be greater than or equal to the first frequency; correspondingly, send the corresponding first transmit signal or the second transmit signal at the second frequency in S101.

3. A non-contact ultrasonic measurement method for strong vibration applications according to claim 2, characterized in that: The number of cycles of the transmitted signal satisfies a second selection rule, and the second selection rule is: 。 4. The non-contact ultrasonic measurement method for strong vibration applications according to claim 3, characterized in that: Prior to S101, it also included: Sending the transmission signal, wherein the number of cycles of the transmission signal is a first set value; receiving a received signal corresponding to the transmitted signal; Determine whether the difference between the frequency of the received signal and the frequency of the transmitted signal falls within a preset frequency difference range. If so, select the number of cycles of the transmitted signal according to a third selection rule, wherein the third selection rule is: the number of cycles of the transmitted signal ≥ the first set value.

5. The non-contact ultrasonic measurement method for strong vibration applications according to claim 3, characterized in that: S102 includes the steps of: S21 performs Fourier transform on the transmission signal to obtain a first Fourier transform complex value, and finds the amplitude of the first Fourier transform complex value. The maximum value of and the corresponding frequency position; S22 performs Fourier transform on the received signal to obtain a second Fourier transform complex value, and obtains a corresponding Fourier transform complex value at the frequency position obtained in S21 in the second Fourier transform complex value; S23 calculates the phase value of the transmitted signal using the real part and the imaginary part of the Fourier transform complex value corresponding to the first Fourier transform complex value at the frequency position, and calculates the phase value of the received signal using the real part and the imaginary part of the Fourier transform complex value corresponding to the second Fourier transform complex value at the same frequency position; S24 calculates a corresponding phase difference according to the phase value of the transmitted signal and the phase value of the received signal.

6. The non-contact ultrasonic measurement method for strong vibration applications according to claim 1, characterized in that: S33 includes the steps of: Determining whether the signal strength in the third Fourier transform complex value belongs to a second strength threshold range; If yes, then execute the steps: Using a frequency domain low-pass filtering method to filter the third Fourier transform complex value, and correspondingly obtain a fourth Fourier transform complex value; Find the maximum peak point in the fourth Fourier transform complex value, and use the position point corresponding to the maximum peak point as the delay time; If not, then perform the following steps: Performing an inverse Fourier transform on the third Fourier transform complex value to obtain a fifth Fourier transform complex value; Squaring the fifth Fourier transform complex value, and performing Fourier transform on the squared fifth Fourier transform complex value to obtain a sixth Fourier transform complex value; The sixth Fourier transform complex value is filtered by using a frequency domain low-pass filtering method, and the seventh Fourier transform complex value is obtained by using an inverse Fourier transform again; The maximum peak point in the seventh Fourier transform complex value is found, and the position point corresponding to the maximum peak point is used as the delay time.

7. The non-contact ultrasonic measurement method for strong vibration applications according to claim 1, characterized in that: The calculation model of the volume flow in S105 is: ； in, represents the volume flow rate, represents the pipe radius, The speed of sound waves in solids Indicates the phase of countercurrent, represents the downstream phase, It represents the angle between the normal direction of the ultrasonic transducer and the normal direction of the pipe wall.

8. A non-contact ultrasonic measuring device for strong vibration applications, characterized in that: include: A signal acquisition module is configured to acquire a downstream signal and an upstream signal, wherein the downstream signal includes: a first transmission signal and a first reception signal corresponding thereto, and the upstream signal includes: a second transmission signal and a second reception signal corresponding thereto; A phase difference calculation module is configured to calculate the downstream phase difference and the upstream phase difference between the transmitted signal and the corresponding received signal in the downstream signal and the upstream signal respectively; The delay time calculation module is configured to respectively calculate the downstream delay time and the upstream delay time of the downstream signal and the upstream signal; wherein the delay time calculation module includes: A first transform unit is configured to perform Fourier transform on the received signal and the transmitted signal respectively, so as to obtain a first Fourier transform complex value and a second Fourier transform complex value correspondingly; a conjugate point multiplication unit configured to perform conjugate point multiplication on the first Fourier transform complex value and the second Fourier transform complex value to obtain a third Fourier transform complex value; A delay time calculation unit is configured to read a corresponding delay time according to the third Fourier transform complex value, wherein the delay time is a position point corresponding to a maximum peak point in the corresponding Fourier transform complex value; A phase calculation module is configured to respectively calculate the downstream phase and the upstream phase according to the downstream phase difference, the upstream phase difference, the downstream delay time and the upstream delay time using a phase calculation model; A volume flow calculation module is configured to calculate the volume flow to be measured according to the phase of the downstream flow and the phase of the upstream flow; wherein the phase calculation model includes: （1）； （2）； in, represents the phase ambiguity number, Indicates the delay time. f represents the signal frequency, represents the phase difference, Indicates phase.

9. The non-contact ultrasonic measuring device for strong vibration applications according to claim 8, characterized in that: Also includes: A first pre-transmission module, configured to send a transmission signal at a first frequency; receiving a received signal corresponding to the transmitted signal; Determine whether the signal strength of the received signal falls within a first strength threshold range; if so, determine a second frequency according to a first selection rule, wherein the first selection rule requires that the second frequency is greater than or equal to the first frequency; correspondingly, send the corresponding first transmit signal or the second transmit signal at the second frequency.

Images