Fluid metering method, device, computer equipment and storage medium

Abstract

The present invention relates to the field of ultrasonic metering technology, and discloses a fluid metering method, device, computer equipment and storage medium, the method comprising: obtaining a downstream ultrasonic signal and a reverse ultrasonic signal of a preset signal length; using autocorrelation filtering and Hilbert filtering and generating a downstream and reverse envelope signal array based on the downstream ultrasonic signal and the reverse ultrasonic signal; calculating the transit time of the upstream and downstream ultrasonic signals based on the downstream and reverse envelope signal arrays, and calculating the time difference between the transit time of the upstream and downstream ultrasonic signals; using correlation calculation based on the transit time and time difference of the upstream and downstream ultrasonic signals to calculate the local maximum value in the downstream ultrasonic signal and the reverse ultrasonic signal; obtaining the corresponding time of the local maximum value, and correcting the time difference based on the corresponding time; and calculating the instantaneous flow rate of the fluid based on the corrected time difference. The present invention solves the problem of large deviation in calculating the instantaneous flow rate using the maximum value due to waveform distortion.

Description

Technical Field

[0001] The present invention relates to the field of ultrasonic metering technology, and in particular to a fluid metering method, device, computer equipment and storage medium. Background Art

[0002] Ultrasonic metering technology in the field of fluid metering is a technology that uses ultrasonic propagation and measurement principles to achieve fluid flow measurement. Compared with complex mechanical structures, fully electronic ultrasonic metering technology has the advantages of higher accuracy, wider measurement range, higher reliability and stability, and better pollution resistance. Therefore, ultrasonic metering technology has achieved rapid development in recent years. When calculating instantaneous flow, the common practice is to take the maximum value after correlation operation of two columns of waveforms, and take the time corresponding to the maximum value to calculate the instantaneous flow. However, when the waveform is distorted, such as the maximum value of each peak of the echo is offset, such as Figure 1 As shown, if the maximum value is used for calculation, the instantaneous flow rate will have a large deviation. Summary of the invention

[0003] In view of this, the present invention provides a fluid metering method, device, computer equipment and storage medium to solve the problem of large deviation in calculating instantaneous flow using maximum value due to waveform distortion.

[0004] In a first aspect, the present invention provides a fluid metering method, the method comprising:

[0005] Acquire a downstream ultrasonic signal and an upstream ultrasonic signal of a preset signal length;

[0006] Using autocorrelation filtering and Hilbert filtering to generate forward and reverse envelope signal arrays based on the forward ultrasonic signal and the reverse ultrasonic signal;

[0007] Calculate the transit time of the uplink ultrasonic signal and the transit time of the downlink ultrasonic signal based on the forward and reverse envelope signal arrays, and calculate the time difference between the transit time of the uplink ultrasonic signal and the transit time of the downlink ultrasonic signal;

[0008] Based on the transit time of the uplink ultrasonic signal, the transit time of the downlink ultrasonic signal and the time difference, a correlation operation is used to calculate the local maximum values ​​in the downstream ultrasonic signal and the upstream ultrasonic signal;

[0009] Obtain the corresponding time of the local maximum value, and correct the time difference based on the corresponding time;

[0010] The instantaneous flow rate of the fluid is calculated based on the corrected time difference.

[0011] The fluid metering method provided by the present invention adopts autocorrelation filtering and Hilbert filtering and generates a forward and reverse envelope signal array based on the downstream ultrasonic signal and the upstream ultrasonic signal, which can reduce the influence of waveform distortion, thereby obtaining more accurate upstream ultrasonic signal transit time and downstream ultrasonic signal transit time, and adopts correlation operation to calculate the local maximum value in the downstream ultrasonic signal and the upstream ultrasonic signal based on the upstream ultrasonic signal transit time, the downstream ultrasonic signal transit time and the time difference, and obtains the corresponding time of the local maximum value, and corrects the time difference based on the corresponding time, so as to achieve the purpose of correcting the time difference by finding the time corresponding to the local maximum value, correct the offset of the peak value in the ultrasonic wave, improve the accuracy of calculating the instantaneous flow of the fluid based on the corrected time difference, overcome the influence of waveform distortion, and solve the problem of large deviation in calculating the instantaneous flow using the maximum value due to waveform distortion.

[0012] In an optional embodiment, the fluid metering method further includes:

[0013] A plurality of pulse sequences are transmitted to a pre-installed transducer by adopting a line frequency modulation method and a preset transmission frequency, so as to excite the transducer to generate a downstream ultrasonic signal and / or an upstream ultrasonic signal.

[0014] The fluid metering method provided by the present invention uses a line frequency modulation method and a preset transmission frequency to transmit multiple pulse sequences to a pre-installed transducer, exciting the transducer to generate a downstream ultrasonic signal and / or a upstream ultrasonic signal, in order to obtain the conditions for the downstream ultrasonic signal and the upstream ultrasonic signal of a preset shape.

[0015] In an optional implementation, using autocorrelation filtering and Hilbert filtering to generate a forward and reverse envelope signal array based on the forward ultrasonic signal and the reverse ultrasonic signal includes:

[0016] Autocorrelation filtering is performed on both the downstream ultrasonic signal and the upstream ultrasonic signal with multiple pulse sequences to generate downstream and upstream echo signal arrays;

[0017] Hilbert filtering is performed on the forward and reverse echo signal arrays to obtain envelope lines, and forward and reverse envelope signal arrays are generated based on the envelope lines.

[0018] The fluid metering method provided by the present invention performs autocorrelation filtering on both the downstream ultrasonic signal and the upstream ultrasonic signal with multiple pulse sequences to generate a downstream and upstream echo signal array; performs Hilbert filtering on the downstream and upstream echo signal arrays to obtain envelope lines, and generates downstream and downstream envelope signal arrays based on the envelope lines, thereby achieving the purpose of filtering out the influence of noise in the ultrasonic signal through autocorrelation filtering and Hilbert filtering, and reducing the influence of waveform distortion.

[0019] In an optional implementation, calculating the uplink ultrasonic signal transit time and the downlink ultrasonic signal transit time based on the forward and reverse envelope signal arrays includes:

[0020] Obtain the turning point from falling to rising in the envelope line from the array of forward and reverse envelope signals, and use the turning point as a feature point;

[0021] The time from the starting point of transmitting multiple pulse sequences to generate downstream ultrasonic signals to the characteristic point is taken as the transit time of the downstream ultrasonic signal, and the time from the starting point of transmitting multiple pulse sequences to generate upstream ultrasonic signals to the characteristic point is taken as the transit time of the upstream ultrasonic signal.

[0022] The fluid metering method provided by the present invention achieves the purpose of using the turning point as the characteristic point for calculating the transit time of the upstream ultrasonic signal and the transit time of the downstream ultrasonic signal by obtaining the turning point from the downstream and downstream envelope signal arrays, and uses the time from the starting time point to the characteristic point of transmitting multiple pulse sequences to generate the downstream ultrasonic signal as the transit time of the downstream ultrasonic signal, and uses the time from the starting point to the characteristic point of transmitting multiple pulse sequences to generate the upstream ultrasonic signal as the transit time of the upstream ultrasonic signal, so that the accuracy of the calculated transit time of the upstream ultrasonic signal and the transit time of the downstream ultrasonic signal reaches the microsecond level, thereby improving the calculation accuracy of the transit time.

[0023] In an optional implementation, calculating the local maximum values ​​of the downstream ultrasonic signal and the upstream ultrasonic signal by using correlation operation based on the upstream ultrasonic signal transit time, the downstream ultrasonic signal transit time and the time difference includes:

[0024] Shift the downstream ultrasonic signal from the transit time of the upstream ultrasonic signal to the transit time of the downstream ultrasonic signal by a unit equal to the value of the time difference;

[0025] Obtain the peak points that overlap after the translation is completed, as well as the negative and positive points of the preset translation units on the left and right sides of the peak points;

[0026] A correlation operation is used to perform three-point correlation calculation based on a peak point, a negative value point and a positive value point, and a peak point correlation calculation result value, a negative value point correlation calculation result value and a positive value point correlation calculation result value are obtained respectively;

[0027] The peak point correlation calculation result value, the negative point correlation calculation result value and the positive point correlation calculation result value are interpolated by cosine interpolation to obtain the interpolation extreme value point, and the interpolation extreme value point is used as the local maximum value of the downstream ultrasonic signal and the upstream ultrasonic signal.

[0028] The fluid metering method provided by the present invention adopts correlation operation to perform three-point correlation calculation based on peak point, negative point and positive point, respectively obtains peak point correlation calculation result value, negative point correlation calculation result value and positive point correlation calculation result value, and performs cosine interpolation on the peak point correlation calculation result value, negative point correlation calculation result value and positive point correlation calculation result value to obtain interpolation extreme value point, and uses the interpolation extreme value point as the local maximum value of the downstream ultrasonic signal and the upstream ultrasonic signal, thereby achieving the purpose of obtaining the local maximum value through correlation calculation and cosine interpolation, and providing conditions for subsequently obtaining the corresponding time of the local maximum value.

[0029] In an optional implementation, obtaining the corresponding time of the local maximum value includes:

[0030] Calculate the offset of the local maximum to the peak point;

[0031] Calculating the corresponding time of the local maximum value based on the offset and the preset sampling frequency. In an optional implementation, correcting the time difference based on the corresponding time includes:

[0032] Calculate the sum of the corresponding time and the time difference;

[0033] Use the sum as the new time difference.

[0034] The fluid metering method provided by the present invention calculates the offset of the local maximum value to the peak point, and calculates the corresponding time of the local maximum value based on the offset and the preset sampling frequency, calculates the sum of the corresponding time and the time difference, and uses the sum as the new time difference, and uses the time difference to correct the offset of the downstream and upstream ultrasonic waves, thereby overcoming the influence of waveform distortion and improving the accuracy of the instantaneous flow rate of the fluid.

[0035] In a second aspect, the present invention provides a fluid metering device, the device comprising:

[0036] A signal acquisition module, used to acquire a downstream ultrasonic signal and an upstream ultrasonic signal of a preset signal length;

[0037] A filtering processing module, used for generating a forward and reverse envelope signal array based on the downstream ultrasonic signal and the upstream ultrasonic signal by using autocorrelation filtering and Hilbert filtering;

[0038] A first time calculation module, used for calculating the transit time of the uplink ultrasonic signal and the transit time of the downlink ultrasonic signal based on the forward and reverse envelope signal arrays, and calculating the time difference between the transit time of the uplink ultrasonic signal and the transit time of the downlink ultrasonic signal;

[0039] A local maximum value calculation module, used to calculate the local maximum values ​​of the downstream ultrasonic signal and the upstream ultrasonic signal by using correlation operation based on the upstream ultrasonic signal transit time, the downstream ultrasonic signal transit time and the time difference;

[0040] A time correction module, used for obtaining the corresponding time of the local maximum value and correcting the time difference based on the corresponding time;

[0041] The flow calculation module is used to calculate the instantaneous flow of the fluid based on the corrected time difference.

[0042] In a third aspect, the present invention provides a computer device, comprising: a memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, and the processor executing the fluid metering method of the first aspect or any corresponding embodiment thereof by executing the computer instructions.

[0043] In a fourth aspect, the present invention provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute the fluid metering method of the first aspect or any corresponding embodiment thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0045] Figure 1 is a schematic diagram showing the deviation of the error obtained by the correlation operation method shown in the prior art from the true value;

[0046] Figure 2 is a schematic flow chart of a fluid metering method according to an embodiment of the present invention;

[0047] Figure 3 is a schematic flow chart of another fluid metering method according to an embodiment of the present invention;

[0048] Figure 4 is a schematic flow chart of another fluid metering method according to an embodiment of the present invention;

[0049] Figure 5 is a schematic flow chart of another fluid metering method according to an embodiment of the present invention;

[0050] Figure 6 is a schematic diagram of an excitation transducer generating a downstream ultrasonic signal and a reverse ultrasonic signal according to an embodiment of the present invention;

[0051] FIG. 7( a ) is a schematic diagram of a downstream ultrasonic signal and a upstream ultrasonic signal of a preset signal length obtained according to an embodiment of the present invention;

[0052] FIG7( b ) is a schematic diagram of a local maximum point and a global maximum point according to an embodiment of the present invention;

[0053] FIG7( c ) is a schematic diagram of a local maximum point according to an embodiment of the present invention;

[0054] Figure 8 is a schematic diagram of filtering and characteristic points of downstream ultrasonic signals and upstream ultrasonic signals according to an embodiment of the present invention;

[0055] Fig. 9 is a logic diagram of a time difference correction algorithm in fluid metering according to an embodiment of the present invention;

[0056] Fig.10 is a structural block diagram of a fluid metering device according to an embodiment of the present invention;

[0057] Fig.11 It is a schematic diagram of the hardware structure of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0058] 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 those skilled in the art without creative work are within the scope of protection of the present invention.

[0059] According to an embodiment of the present invention, an embodiment of a fluid metering method is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0060] In this embodiment, a fluid metering method is provided, which can be used in a fluid meter, such as a gas meter. Figure 2 is a flow chart of a fluid metering method according to an embodiment of the present invention. Figure 2 As shown, the process includes the following steps:

[0061] Step S101, acquiring a downstream ultrasonic signal and an upstream ultrasonic signal of a preset signal length.

[0062] Specifically, the fluid meter includes a flow channel, and a transducer is installed on the cavity wall of the flow channel. The transducer is excited to generate a downstream ultrasonic signal and a downstream ultrasonic signal by emitting a pulse to the transducer, and the downstream ultrasonic signal and the upstream ultrasonic signal of a preset signal length are obtained by collecting multiple ultrasonic signal points. The preset signal length can be a signal length that enables the downstream ultrasonic signal and the upstream ultrasonic signal to form a shape of first rising and then falling, which is selected according to actual conditions and is not specifically limited here.

[0063] Step S102, using autocorrelation filtering and Hilbert filtering to generate a forward and reverse envelope signal array based on the downstream ultrasonic signal and the upstream ultrasonic signal.

[0064] Specifically, autocorrelation filtering is a filtering method based on signal autocorrelation, which can filter out random noise in the signal. Hilbert filtering is a signal processing technology that can be used to process periodic signals. It is achieved by convolving the signal with a Hilbert transformer. Hilbert filtering can also remove random noise in the signal and avoid the influence of random noise on downstream ultrasonic signals and upstream ultrasonic signals. Hilbert filtering can also be used to obtain the envelopes of downstream ultrasonic signals and upstream ultrasonic signals to generate arrays of downstream and upstream envelope signals.

[0065] Step S103, calculating the uplink ultrasonic signal transit time and the downlink ultrasonic signal transit time based on the forward and reverse envelope signal arrays, and calculating the time difference between the uplink ultrasonic signal transit time and the downlink ultrasonic signal transit time.

[0066] Specifically, the wave transit time refers to the time required for ultrasonic waves to be transmitted and received, including the time it takes for the ultrasonic wave to propagate in the medium and the time it takes for the detected object to reflect back. The transit time of the uplink ultrasonic signal refers to the transit time of the upstream envelope signal, and the transit time of the downlink ultrasonic signal refers to the transit time of the downstream envelope signal. The time difference is obtained by subtracting the transit time of the downlink ultrasonic signal from the transit time of the uplink ultrasonic signal.

[0067] Step S104, using correlation operation to calculate the local maximum values ​​of the downstream ultrasonic signal and the upstream ultrasonic signal based on the upstream ultrasonic signal transit time, the downstream ultrasonic signal transit time and the time difference.

[0068] Specifically, the correlation operation is a mathematical operation for comparing the similarity of two sequences, that is, the correlation operation is achieved by comparing the transit time of the uplink ultrasonic signal with the transit time of the downlink ultrasonic signal, and comparing the transit time of the uplink ultrasonic signal with the time difference. The local maximum refers to the point where the function value reaches the maximum in a certain area. In this embodiment, the local maximum refers to the interpolation extreme point when the downstream ultrasonic signal and the upstream ultrasonic signal coincide.

[0069] Step S105, obtaining the corresponding time of the local maximum value, and correcting the time difference based on the corresponding time.

[0070] Specifically, the time point corresponding to the local maximum value is determined, the time point corresponding to the local maximum value and the time difference are accumulated, and the accumulated time is used to correct the deviation of the peak value.

[0071] Step S106, calculating the instantaneous flow rate of the fluid based on the corrected time difference.

[0072] Specifically, the corrected time difference is taken as the difference in the transit time of the downstream and upstream ultrasonic signals. , calculate the instantaneous flow rate according to the following formula:

[0073]

[0074] In the formula, is the cross-sectional area of ​​the flow channel, is the coefficient for converting linear velocity into surface velocity, is the speed of sound, For the sound path, is the angle between the gas flow direction and the ultrasonic propagation direction.

[0075] The fluid metering method provided in this embodiment adopts autocorrelation filtering and Hilbert filtering and generates a forward and reverse envelope signal array based on the downstream ultrasonic signal and the upstream ultrasonic signal, which can reduce the influence of waveform distortion, and thus obtain more accurate upstream ultrasonic signal transit time and downstream ultrasonic signal transit time. Based on the upstream ultrasonic signal transit time, the downstream ultrasonic signal transit time and the time difference, a correlation operation is adopted to calculate the local maximum value in the downstream ultrasonic signal and the upstream ultrasonic signal, and the corresponding time of the local maximum value is obtained, and the time difference is corrected based on the corresponding time, so as to achieve the purpose of correcting the time difference by finding the time corresponding to the local maximum value, correct the peak value in the ultrasonic wave, improve the accuracy of calculating the instantaneous flow of the fluid based on the corrected time difference, overcome the influence of waveform distortion, and solve the problem of large deviation in calculating the instantaneous flow using the maximum value due to waveform distortion.

[0076] In this embodiment, a fluid metering method is provided, which can be used in a fluid meter, such as a gas meter. Figure 3 is a flow chart of a fluid metering method according to an embodiment of the present invention. Figure 3 As shown, the process includes the following steps:

[0077] Step S201, using line frequency modulation and a preset transmission frequency to transmit multiple pulse sequences to a pre-installed transducer, to stimulate the transducer to generate downstream ultrasonic signals and / or upstream ultrasonic signals. Figure 6As shown, taking a gas meter as an example, the gas meter includes a flow channel, such as Figure 6 The air intake chamber is the flow channel. Two transducers are installed on the wall of the flow channel. The installation positions of the two transducers are specifically: one of the transducers can generate ultrasonic waves that are reflected to the other transducer. The center frequency of the transducer is 200k (k represents kilobytes). One of the transducers with a center frequency of 200k installed in the flow channel of the gas meter is excited by a pulse sequence composed of several pulses generated in a linear frequency modulation manner and with a frequency between 180k and 240k, which excites the transducer to generate downstream ultrasonic signals and / or upstream ultrasonic signals. Figure 6 The angle θ in the equation represents the angle between the ultrasonic wave propagation direction and the air intake direction.

[0078] Step S202, obtain the downstream ultrasonic signal and the upstream ultrasonic signal of the preset signal length. Specifically, when one of the transducers generates an ultrasonic signal, the ultrasonic wave is reflected to the other transducer due to the reflection phenomenon, and the ultrasonic signal is received by the other transducer to form a downstream ultrasonic signal. Similarly, a downstream ultrasonic signal can also be generated. The microcontroller MCU (Microcontroller Unit) is used to collect ultrasonic signals at a sampling frequency of 1M / s (megabits per second). During the collection, the signal length is required to fully present the shape of the overall trend of the ultrasonic envelope first rising and then falling, and the highest amplitude point requirement is: after AD conversion (analog-to-digital conversion), amplification and shaping, saturation cannot occur. In this embodiment, 200 points of a total of 200us (microseconds) length of signal are taken, as shown in Figure 7 (a), and the envelope shape corresponding to several pulses is completely displayed in the figure by the ultrasonic signal that rises first and then falls. The amplitude of each point in the downstream ultrasonic signal and the upstream ultrasonic signal forms an (X0, Y0) echo signal array.

[0079] Step S203, using autocorrelation filtering and Hilbert filtering to generate a forward and reverse envelope signal array based on the downstream ultrasonic signal and the upstream ultrasonic signal.

[0080] Specifically, the above step S203 includes:

[0081] Step S2031, autocorrelation filtering is performed on both the downstream ultrasonic signal and the upstream ultrasonic signal and a plurality of pulse sequences to generate arrays of downstream and upstream echo signals.

[0082] Specifically, Figure 5 and Figure 8 As shown, the forward and reverse echo signal arrays X0, Y0 are autocorrelated with multiple pulse sequences to filter out random noise, thereby forming the forward and reverse echo signal arrays X1, Y1.

[0083] Step S2032, performing Hilbert filtering on the arrays of forward and reverse echo signals to obtain envelopes, and generating arrays of forward and reverse envelope signals based on the envelopes.

[0084] Specifically, Figure 8 As shown, the forward and reverse echo signal arrays X1 and Y1 are Hilbert filtered to obtain the envelope to form the forward and reverse envelope signal arrays X2 and Y2.

[0085] Step S204, calculating the uplink ultrasonic signal transit time and the downlink ultrasonic signal transit time based on the forward and reverse envelope signal arrays, and calculating the time difference between the uplink ultrasonic signal transit time and the downlink ultrasonic signal transit time.

[0086] Specifically, the above step S204 includes:

[0087] Step S2041, obtaining the turning point from the falling to the rising in the envelope line from the array of the forward and reverse envelope signals, and taking the turning point as the feature point.

[0088] Specifically, Figure 8 As shown, the turning point of the falling and rising of the envelope line in the circle is the corresponding point of the first excitation pulse starting signal, that is, the characteristic point for calculating the transit time of the uplink ultrasonic signal and the transit time of the downlink ultrasonic signal.

[0089] Step S2042, the time from the starting point of transmitting multiple pulse sequences to generate downstream ultrasonic signals to the characteristic point is used as the transit time of the downstream ultrasonic signal, and the time from the starting point of transmitting multiple pulse sequences to generate upstream ultrasonic signals to the characteristic point is used as the transit time of the upstream ultrasonic signal.

[0090] Specifically, the time from the starting point of transmitting multiple pulse sequences to generate downstream ultrasonic signals to the characteristic point is taken as the downstream ultrasonic signal transit time t2, and the time from the starting point of transmitting multiple pulse sequences to generate upstream ultrasonic signals to the characteristic point is taken as the upstream ultrasonic signal transit time t1.

[0091] The time difference Δt is obtained by subtracting the transit time of the downlink ultrasonic signal from the transit time of the uplink ultrasonic signal.

[0092] It should be noted that since the sampling period is 1us (microseconds), the accuracy of the time difference Δt between t1 and t2 is 1us. If it is known that the time difference is less than 1us under a small flow rate, the time difference Δt between t1 and t2 is 0.

[0093] Step S205, based on the uplink ultrasonic signal transit time, the downlink ultrasonic signal transit time and the time difference, a correlation operation is used to calculate the local maximum of the downstream ultrasonic signal and the upstream ultrasonic signal. Figure 2 Step S104 of the illustrated embodiment will not be described in detail here.

[0094] Step S206, obtaining the corresponding time of the local maximum value, and correcting the time difference based on the corresponding time. Figure 2 Step S105 of the illustrated embodiment will not be described in detail here.

[0095] Step S207, calculate the instantaneous flow rate of the fluid based on the corrected time difference. Figure 2 Step S106 of the illustrated embodiment will not be described in detail here.

[0096] The fluid metering method provided in this embodiment performs autocorrelation filtering on both the downstream ultrasonic signal and the upstream ultrasonic signal with multiple pulse sequences to generate a downstream and upstream echo signal array; performs Hilbert filtering on the downstream and upstream echo signal array to obtain an envelope, and generates a downstream and upstream envelope signal array based on the envelope, thereby achieving the purpose of filtering out the noise influence in the ultrasonic signal through autocorrelation filtering and Hilbert filtering, and reducing the influence of waveform distortion. By obtaining the turning point from the falling to the rising in the envelope from the downstream and upstream envelope signal array, the turning point is used as the characteristic point for calculating the transit time of the upstream ultrasonic signal and the transit time of the downstream ultrasonic signal, and the time from the starting time point to the characteristic point of the emission of multiple pulse sequences to generate the downstream ultrasonic signal is used as the transit time of the downstream ultrasonic signal, and the time from the starting point to the characteristic point of the emission of multiple pulse sequences to generate the upstream ultrasonic signal is used as the transit time of the upstream ultrasonic signal, so that the accuracy of the calculated transit time of the upstream ultrasonic signal and the transit time of the downstream ultrasonic signal reaches the microsecond level, thereby improving the calculation accuracy of the transit time.

[0097] In this embodiment, a fluid metering method is provided, which can be used in a fluid meter, such as a gas meter. Figure 4 is a flow chart of a fluid metering method according to an embodiment of the present invention. Figure 4 As shown, the process includes the following steps:

[0098] Step S301, obtaining a downstream ultrasonic signal and an upstream ultrasonic signal of a preset signal length. Figure 3 Step S202 of the illustrated embodiment will not be described in detail here.

[0099] Step S302, using autocorrelation filtering and Hilbert filtering to generate a forward and reverse envelope signal array based on the downstream ultrasonic signal and the upstream ultrasonic signal. Figure 3 Step S203 of the illustrated embodiment will not be described in detail here.

[0100] Step S303, based on the forward and reverse envelope signal arrays, calculate the uplink ultrasonic signal transit time and the downlink ultrasonic signal transit time, and calculate the time difference between the uplink ultrasonic signal transit time and the downlink ultrasonic signal transit time. Figure 3Step S204 of the illustrated embodiment will not be described in detail here.

[0101] Step S304, using correlation operation to calculate the local maximum values ​​of the downstream ultrasonic signal and the upstream ultrasonic signal based on the upstream ultrasonic signal transit time, the downstream ultrasonic signal transit time and the time difference.

[0102] Specifically, Fig. 9 The logic diagram of the time difference correction algorithm in the fluid metering of the embodiment of the present invention is shown, and the above step S304 includes:

[0103] Step S3041, shifting the downstream ultrasonic signal from the transit time of the upstream ultrasonic signal to the transit time of the downstream ultrasonic signal by a unit equal to the time difference value.

[0104] Specifically, the time difference Δt between the transit time t1 of the uplink ultrasonic signal and the transit time t2 of the downlink ultrasonic signal is obtained by the above steps. The downstream ultrasonic signal X0 in the upstream echo signal array is translated in the direction of the upstream ultrasonic signal by a unit equal to the value of the time difference Δt, and the maximum value point of the correlation operation after interference filtering is located near the peak value after translation. This maximum value point is not the global maximum value point obtained by performing a global correlation operation on the signal after interference, but refers to the local maximum value point near the peak point, as shown in Figure 7 (b), serial number -15 is the global maximum value point, and -20 is the local maximum value point.

[0105] Step S3042, obtaining the peak points that overlap after the translation is completed, as well as the negative and positive points of the preset translation units to the left and right of the peak points.

[0106] Specifically, the peak point that overlaps after the translation is completed is represented by m=0, and the preset unit is selected as 1 numerical unit, then the negative and positive points of the preset translation units to the left and right of the peak point are represented by m=-1 and m=1 respectively.

[0107] Step S3043, using correlation operation to perform three-point correlation calculation based on the peak point, negative value point and positive value point, and obtain the peak point correlation calculation result value, the negative value point correlation calculation result value and the positive value point correlation calculation result value respectively.

[0108] Specifically, a correlation operation is used to perform three-point correlation calculation based on the peak point m=0, the negative point m=-1 and the positive point m=1. The calculation formula is as follows:

[0109]

[0110] in, is the peak point correlation calculation result value, then the negative point correlation calculation result value and the positive point correlation calculation result value are respectively and ; N is equal to 200, which is the total signal length of the downstream ultrasonic signal X0 and the downstream ultrasonic signal Y0.

[0111] Step S3044, performing cosine interpolation on the peak point correlation calculation result value, the negative point correlation calculation result value and the positive point correlation calculation result value to obtain the interpolation extreme value point, and taking the interpolation extreme value point as the local maximum value of the downstream ultrasonic signal and the upstream ultrasonic signal.

[0112] Specifically, the peak point correlation calculation result value , Negative point related calculation result value Calculation result value related to positive point Perform cosine interpolation to obtain the interpolation extreme point. The calculation formula is as follows:

[0113]

[0114] in, , are all cosine interpolation intermediate variable results; m is the time sequence number or deviation corresponding to the local maximum value.

[0115] Step S305, obtaining the corresponding time of the local maximum value, and correcting the time difference based on the corresponding time.

[0116] Specifically, the corresponding time of obtaining the local maximum value in the above step S305 includes:

[0117] Step S3051, calculating the offset of the local maximum value to the peak point.

[0118] Specifically, the formula for calculating the offset of the local maximum to the peak point is as follows:

[0119]

[0120] in, Represents the cosine interpolation spacing, that is, the offset of the local maximum to the peak point.

[0121] Step S3052, calculating the corresponding time of the local maximum value based on the offset and the preset sampling frequency.

[0122] Specifically, the calculation formula for calculating the corresponding time of the local maximum value based on the offset and the preset sampling frequency is as follows:

[0123]

[0124] in, Indicates the sampling frequency of the microcontroller MCU collecting ultrasonic signals.

[0125] Specifically, in the above step S305, correcting the time difference based on the corresponding time includes:

[0126] Step S3053, calculating the sum of the corresponding time and the time difference.

[0127] Step S3054, taking the sum value as the new time difference.

[0128] Specifically, after the corresponding time of the local maximum value is obtained, the sum of the corresponding time and the time difference is calculated, and the time difference Δt is corrected by using the sum. The corrected time difference is obtained using the corresponding time of the local maximum point , which solves the impact of waveform distortion on related calculations.

[0129] Step S306, calculate the instantaneous flow rate of the fluid based on the corrected time difference. Figure 2 Step S207 of the illustrated embodiment will not be described in detail here.

[0130] As shown in Figure 7(b), if we follow Figure 1 If the global maximum value method is used for calculation, the calculation result is obviously greater than 1us, which does not conform to the actual measurement. According to the fluid metering method provided in this embodiment, the calculation result is 0.125319us, and the flow accuracy is within 1%. At the same time, the fluid metering method provided in this embodiment only carries out 3 correlation operations, while the global correlation of the 200-point downstream ultrasonic signal and upstream ultrasonic signal shown in Figure 7 (a) requires 200 correlation operations. The fluid metering method provided in this embodiment has high calculation efficiency. Upward recorded in Figure 7 (a) represents the upstream ultrasonic signal, and Downward represents the downstream ultrasonic signal.

[0131] If the global maximum value method is used for calculation, as shown in Figure 7 (b), the deviation corresponding to the highest value is 15, which does not conform to the actual measurement. However, according to the local maximum value method, t1=176500, t2=195833, The corresponding deviation is 20, that is The obtained correlation coefficient meets the requirement of large in the middle and small on both sides. After cosine interpolation operation, we get ,Right now According to the fluid metering method provided in this embodiment, only three correlation operations are performed, as shown in FIG7 (c); while for the 200 points of downstream ultrasonic signals and upstream ultrasonic signals, 399 correlation operations are performed for global correlation, as shown in FIG7 (b). The fluid metering method provided in this embodiment has high computational efficiency.

[0132] The fluid metering method provided in this embodiment uses correlation operation to perform three-point correlation calculation based on peak point, negative point and positive point, respectively obtain peak point correlation calculation result value, negative point correlation calculation result value and positive point correlation calculation result value, and perform cosine interpolation on the peak point correlation calculation result value, negative point correlation calculation result value and positive point correlation calculation result value to obtain interpolation extreme value point, and use the interpolation extreme value point as the local maximum value of the downstream ultrasonic signal and the upstream ultrasonic signal, so as to achieve the purpose of obtaining the local maximum value through correlation calculation and cosine interpolation, and provide conditions for obtaining the corresponding time of the local maximum value in the subsequent process. By calculating the offset of the local maximum value to the peak point, and calculating the corresponding time of the local maximum value based on the offset and the preset sampling frequency, by calculating the sum of the corresponding time and the time difference, and using the sum as the new time difference, the time difference is used to correct the offset of the downstream and upstream ultrasonic waves, the influence of waveform distortion is overcome, and the accuracy of the instantaneous flow of the fluid is improved. In this embodiment, a fluid metering device is also provided, which is used to implement the above-mentioned embodiment and preferred implementation mode, and the description has been made and will not be repeated. As used below, the term "module" may be a combination of software and / or hardware that implements a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware is also possible and contemplated.

[0133] This embodiment provides a fluid metering device, such as Fig.10 As shown, including:

[0134] The signal acquisition module 1001 is used to acquire downstream ultrasonic signals and upstream ultrasonic signals of preset signal lengths.

[0135] The filtering processing module 1002 is used to generate a forward and reverse envelope signal array based on the downstream ultrasonic signal and the upstream ultrasonic signal by using autocorrelation filtering and Hilbert filtering.

[0136] The first time calculation module 1003 is used to calculate the transit time of the uplink ultrasonic signal and the transit time of the downlink ultrasonic signal based on the forward and reverse envelope signal arrays, and calculate the time difference between the transit time of the uplink ultrasonic signal and the transit time of the downlink ultrasonic signal.

[0137] The local maximum value calculation module 1004 is used to calculate the local maximum values ​​in the downstream ultrasonic signal and the upstream ultrasonic signal by using correlation operation based on the upstream ultrasonic signal transit time, the downstream ultrasonic signal transit time and the time difference.

[0138] The time correction module 1005 is used to obtain the corresponding time of the local maximum value and correct the time difference based on the corresponding time.

[0139] The flow calculation module 1006 is used to calculate the instantaneous flow of the fluid based on the corrected time difference.

[0140] In some optional embodiments, the fluid metering device further comprises:

[0141] The signal transmission excitation module is used to transmit multiple pulse sequences to the pre-installed transducer using a line frequency modulation method and a preset transmission frequency, so as to excite the transducer to generate a downstream ultrasonic signal and / or an upstream ultrasonic signal.

[0142] In some optional implementations, the filtering processing module 1002 includes:

[0143] The autocorrelation filtering unit is used to perform autocorrelation filtering on both the downstream ultrasonic signal and the upstream ultrasonic signal and a plurality of pulse sequences to generate arrays of downstream and upstream echo signals.

[0144] The Hilbert filter unit is used to perform Hilbert filtering on the forward and reverse echo signal arrays to obtain envelope lines, and to generate forward and reverse envelope signal arrays based on the envelope lines.

[0145] In some optional implementations, the first time calculation module 1003 includes:

[0146] The feature point acquisition unit is used to acquire the turning point from the falling to the rising in the envelope line from the forward and reverse envelope signal arrays, and use the turning point as the feature point.

[0147] The transit time calculation unit is used to use the time from the starting time point of transmitting multiple pulse sequences to generate downstream ultrasonic signals to the characteristic point as the transit time of the downstream ultrasonic signal, and use the time from the starting point of transmitting multiple pulse sequences to generate upstream ultrasonic signals to the characteristic point as the transit time of the upstream ultrasonic signal. In some optional embodiments, the local maximum value calculation module 1004 includes:

[0148] The translation unit is used to translate the downstream ultrasonic signal from the transit time of the upstream ultrasonic signal to the transit time of the downstream ultrasonic signal by a unit equal to the time difference value.

[0149] The three-point acquisition unit is used to acquire the peak point that overlaps after the translation is completed, as well as the negative and positive points of the preset translation units on the left and right of the peak point.

[0150] The correlation operation unit is used to perform three-point correlation calculation based on the peak point, the negative value point and the positive value point by using correlation operation to obtain the peak point correlation calculation result value, the negative value point correlation calculation result value and the positive value point correlation calculation result value respectively.

[0151] The cosine interpolation unit is used to perform cosine interpolation on the peak point correlation calculation result value, the negative point correlation calculation result value and the positive point correlation calculation result value to obtain the interpolation extreme value point, and use the interpolation extreme value point as the local maximum value of the downstream ultrasonic signal and the upstream ultrasonic signal.

[0152] In some optional implementations, the time correction module 1005 includes:

[0153] The offset calculation unit is used to calculate the offset of the local maximum value to the peak point.

[0154] The corresponding time calculation unit is used to calculate the corresponding time of the local maximum value based on the offset and the preset sampling frequency.

[0155] The sum calculation unit is used to calculate the sum of the corresponding time and the time difference.

[0156] The time difference correction unit is used to take the sum value as the new time difference.

[0157] The further functional description of each of the above modules and units is the same as that of the above corresponding embodiments and will not be repeated here.

[0158] The fluid metering device in this embodiment is presented in the form of a functional unit, where the unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions.

[0159] The embodiment of the present invention also provides a computer device having the above Fig.10 The fluid metering device shown.

[0160] See also Fig.11 , Fig.11 is a schematic diagram of the structure of a computer device provided by an optional embodiment of the present invention, such as Fig.11 As shown, the computer device includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. Various components are connected to each other using different buses for communication, and can be installed on a common mainboard or installed in other ways as needed. The processor can process the instructions executed in the computer device, including instructions stored in or on the memory to display the graphical information of the GUI on an external input / output device (such as, a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple computer devices can be connected, and each device provides some necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Fig.11 A processor 10 is taken as an example.

[0161] The processor 10 may be a central processing unit, a network processor or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be a dedicated integrated circuit, a programmable logic device or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic or any combination thereof.

[0162] The memory 20 stores instructions executable by at least one processor 10, so that the at least one processor 10 executes the method shown in the above embodiment.

[0163] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function; the data storage area may store data created according to the use of the computer device, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory 20 may optionally include a memory remotely arranged relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0164] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid state drive; the memory 20 may also include a combination of the above types of memory.

[0165] The computer device also includes an input device 30 and an output device 40. The processor 10, the memory 20, the input device 30 and the output device 40 may be connected via a bus or other means. Fig.11 The example of connecting through bus is taken in the following.

[0166] The input device 30 can receive input digital or character information, and generate key signal input related to the user settings and function control of the computer device, such as a touch screen, a keypad, a mouse, a track pad, a touch pad, an indicator bar, one or more mouse buttons, a trackball, a joystick, etc. The output device 40 may include a display device, an auxiliary lighting device (e.g., an LED) and a tactile feedback device (e.g., a vibration motor), etc. The above-mentioned display device includes but is not limited to a liquid crystal display, a light emitting diode, a display and a plasma display. In some optional embodiments, the display device may be a touch screen.

[0167] The embodiment of the present invention also provides a computer-readable storage medium. The method according to the embodiment of the present invention can be implemented in hardware, firmware, or can be implemented as a computer code that can be recorded in a storage medium, or can be implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and will be stored in a local storage medium through a network download, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state hard disk, etc.; further, the storage medium can also include a combination of the above types of memories. It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor, or hardware, the method shown in the above embodiment is implemented.

[0168] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A fluid metering method, characterized in that: The method comprises: Acquire a downstream ultrasonic signal and an upstream ultrasonic signal of a preset signal length; Using autocorrelation filtering and Hilbert filtering to generate a forward and reverse envelope signal array based on the forward ultrasonic signal and the reverse ultrasonic signal; Calculate the transit time of the uplink ultrasonic signal and the transit time of the downlink ultrasonic signal based on the forward and reverse envelope signal arrays, and calculate the time difference between the transit time of the uplink ultrasonic signal and the transit time of the downlink ultrasonic signal; Calculate the local maximum values ​​of the downstream ultrasonic signal and the upstream ultrasonic signal by using correlation operation based on the upstream ultrasonic signal transit time, the downstream ultrasonic signal transit time and the time difference; Calculating the local maximum values ​​of the downstream ultrasonic signal and the upstream ultrasonic signal by using correlation operation based on the upstream ultrasonic signal transit time, the downstream ultrasonic signal transit time and the time difference includes: Shifting the downstream ultrasonic signal from the transit time of the upstream ultrasonic signal to the transit time of the downstream ultrasonic signal by a unit equal to the value of the time difference; Obtain the peak points that overlap after the translation is completed, as well as the negative and positive points of the preset translation units on the left and right sides of the peak points; A correlation operation is used to perform three-point correlation calculation based on the peak point, the negative value point and the positive value point, to obtain a peak point correlation calculation result value, a negative value point correlation calculation result value and a positive value point correlation calculation result value respectively; Performing cosine interpolation on the peak point correlation calculation result value, the negative point correlation calculation result value and the positive point correlation calculation result value to obtain an interpolation extreme value point, and taking the interpolation extreme value point as the local maximum value of the downstream ultrasonic signal and the upstream ultrasonic signal; Obtaining a corresponding time of the local maximum value, and correcting the time difference based on the corresponding time; The corresponding time of obtaining the local maximum value includes: Calculating the offset of the local maximum value to the peak point; Calculate the corresponding time of the local maximum value based on the offset and the preset sampling frequency; Correcting the time difference based on the corresponding time includes: Calculating a sum of the corresponding time and the time difference; Taking the sum as the new time difference; Calculate the instantaneous flow rate of the fluid based on the corrected time difference; The corrected time difference is used as the transit time difference of the upstream and downstream ultrasonic signals. , calculate the instantaneous flow rate according to the following formula: In the formula, is the cross-sectional area of ​​the flow channel, is the coefficient for converting linear velocity into surface velocity, is the speed of sound, For the sound path, is the angle between the gas flow direction and the ultrasonic propagation direction.

2. The fluid metering method according to claim 1, characterized in that: The method further comprises: A plurality of pulse sequences are transmitted to a pre-installed transducer using a line frequency modulation method and a preset transmission frequency, so as to stimulate the transducer to generate a downstream ultrasonic signal and / or an upstream ultrasonic signal.

3. The fluid metering method according to claim 2, characterized in that: Using autocorrelation filtering and Hilbert filtering to generate a forward and reverse envelope signal array based on the forward ultrasonic signal and the reverse ultrasonic signal includes: Performing autocorrelation filtering on the downstream ultrasonic signal and the upstream ultrasonic signal with a plurality of pulse sequences to generate downstream and upstream echo signal arrays; Perform Hilbert filtering on the forward and reverse echo signal arrays to obtain envelopes, and generate forward and reverse envelope signal arrays based on the envelopes.

4. The fluid metering method according to claim 2, characterized in that: Calculating the uplink ultrasonic signal transit time and the downlink ultrasonic signal transit time based on the forward and reverse envelope signal arrays includes: Obtaining a turning point from a drop to an increase in the envelope line from the array of the forward and reverse envelope signals, and taking the turning point as a feature point; The time from the starting time point of transmitting multiple pulse sequences to generate downstream ultrasonic signals to the characteristic point is taken as the transit time of the downstream ultrasonic signal, and the time from the starting point of transmitting multiple pulse sequences to generate upstream ultrasonic signals to the characteristic point is taken as the transit time of the upstream ultrasonic signal.

5. A fluid metering device, characterized in that: The device comprises: A signal acquisition module, used to acquire a downstream ultrasonic signal and an upstream ultrasonic signal of a preset signal length; A filtering processing module, used for generating a forward and reverse envelope signal array based on the forward ultrasonic signal and the reverse ultrasonic signal by using autocorrelation filtering and Hilbert filtering; A first time calculation module, used for calculating the transit time of the uplink ultrasonic signal and the transit time of the downlink ultrasonic signal based on the forward and reverse envelope signal arrays, and calculating the time difference between the transit time of the uplink ultrasonic signal and the transit time of the downlink ultrasonic signal; A local maximum value calculation module, used to calculate the local maximum values ​​in the downstream ultrasonic signal and the upstream ultrasonic signal by using correlation operation based on the upstream ultrasonic signal transit time, the downstream ultrasonic signal transit time and the time difference; Calculating the local maximum values ​​of the downstream ultrasonic signal and the upstream ultrasonic signal by using correlation operation based on the upstream ultrasonic signal transit time, the downstream ultrasonic signal transit time and the time difference includes: Shifting the downstream ultrasonic signal from the transit time of the upstream ultrasonic signal to the transit time of the downstream ultrasonic signal by a unit equal to the value of the time difference; Obtain the peak points that overlap after the translation is completed, as well as the negative and positive points of the preset translation units on the left and right sides of the peak points; A correlation operation is used to perform three-point correlation calculation based on the peak point, the negative value point and the positive value point, to obtain a peak point correlation calculation result value, a negative value point correlation calculation result value and a positive value point correlation calculation result value respectively; Performing cosine interpolation on the peak point correlation calculation result value, the negative point correlation calculation result value and the positive point correlation calculation result value to obtain an interpolation extreme value point, and taking the interpolation extreme value point as the local maximum value of the downstream ultrasonic signal and the upstream ultrasonic signal; A time correction module, used for obtaining the corresponding time of the local maximum value and correcting the time difference based on the corresponding time; The corresponding time of obtaining the local maximum value includes: Calculating the offset of the local maximum value to the peak point; Calculate the corresponding time of the local maximum value based on the offset and the preset sampling frequency; Correcting the time difference based on the corresponding time includes: Calculating a sum of the corresponding time and the time difference; Taking the sum as the new time difference; A flow calculation module, used for calculating the instantaneous flow of the fluid based on the corrected time difference; The corrected time difference is used as the transit time difference of the upstream and downstream ultrasonic signals. , calculate the instantaneous flow rate according to the following formula: In the formula, is the cross-sectional area of ​​the flow channel, is the coefficient for converting linear velocity into surface velocity, is the speed of sound, For the sound path, is the angle between the gas flow direction and the ultrasonic propagation direction.

6. A computer device, characterized in that: include: A memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the fluid metering method according to any one of claims 1 to 4 by executing the computer instructions.

7. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a computer to execute the fluid metering method according to any one of claims 1 to 4.

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