Vibration-based meter and structural parameter diagnosis method therefor

Abstract

A vibration-based meter and a structural parameter diagnosis method therefor. The method comprises: providing a first excitation signal to excite a measurement tube; obtaining a first vibration response signal and a first vibration frequency; providing a second excitation signal, the first excitation signal and the second excitation signal jointly acting to excite the measurement tube, the second excitation signal being configured to have a fixed signal gain, and the second excitation signal differing from the first excitation signal by a preset phase; adjusting a signal gain of the first excitation signal; obtaining a second vibration response signal and a second vibration frequency; and on the basis of the first vibration frequency, the second vibration frequency, the signal gain of the second excitation signal, the adjusted signal gain of the first excitation signal, and the phase difference between the two excitation signals, calculating the following structural parameters: a mass coefficient, a stiffness coefficient, and a damping coefficient. The method can provide early warning for the situations such as wear or corrosion of a measurement tube.

Description

A vibration-based metering instrument and its structural parameter diagnostic method

[0001] This application claims priority to Chinese Patent Application No. 202411825755.5, filed on December 11, 2024, entitled "A vibration-based measuring instrument and a diagnostic method for its structural parameters", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of intelligent diagnosis and signal processing technology for vibration-based metering instruments, and in particular to a method for diagnosing vibration-based metering instruments and their structural parameters. Background Technology

[0003] By utilizing the frequency, phase, and amplitude information of the vibrating measuring tube, the density, mass flow rate, and viscosity of the medium inside can be calculated. Therefore, it can be used to manufacture various vibration-based metering instruments, including Coriolis mass flow meters and density-viscosity meters. The structural parameters of vibration-based metering instruments have a significant impact on their metering performance. For example, the measuring tube in a Coriolis mass flow meter (hereinafter referred to as a Coriolis mass flow meter) is constantly in a resonant state. When fluid flows through it, the fluid exerts a Coriolis force on the measuring tube, causing a slight twist in the tube. This results in a time difference between the vibration at the inlet and outlet of the measuring tube, and this time difference is proportional to the mass flow rate. The proportionality coefficient is closely related to the stiffness of the measuring tube. If the stiffness remains constant, the mass flow rate reading of the Coriolis mass flow meter can be considered reliable. Of course, temperature and pressure compensation coefficients are generally introduced to compensate for changes in the stiffness of the Coriolis mass flow meter caused by temperature and pressure. However, if the measuring tube of the Coriolis mass flow meter corrodes or wears due to certain reasons (such as long-term measurement of corrosive fluids or solid-liquid mixtures), a change in stiffness will also occur, and the mass flow rate reading will no longer be accurate and reliable. Therefore, it is necessary to introduce structure-related intelligent diagnostic technology into Coriolis mass flow meters to monitor the health status of the structure, so as to provide timely warnings when significant changes in stiffness occur.

[0004] In existing technologies, the structural parameters of vibration-based measuring instruments are often determined by designing additional filters. This method is complex, consumes the computing resources of the measuring instrument during the calculation process, and increases the cost of the measuring instrument by adding additional filters. In addition, some structural parameter diagnosis methods affect the real-time measurement of the measuring instrument and cannot perform structural parameter diagnosis while measuring.

[0005] In US10598534 B2, a method is reported that uses a phase-locked loop to lock the measuring tube in a non-zero phase to make the measuring tube vibrate at a non-resonant frequency, thereby reducing the influence of damping on density measurement.

[0006] This paper introduces two excitation signals, one of which is in phase with the sensor signal, and quantitatively and accurately reveals the relationship between gain, non-zero phase and resonant frequency, and uses this relationship to obtain structural parameters. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the purpose of this application is to provide a method for diagnosing the structural parameters of vibration-based measuring instruments. This application can determine the structural health of vibration-based measuring instruments under their current state and provide early warnings of wear or corrosion of measuring tubes.

[0008] To achieve the above objectives, this application adopts the following technical solution:

[0009] In a first aspect, this application provides a method for diagnosing the structural parameters of a vibration-based measuring instrument, the measuring instrument including a measuring tube, a vibrator, and a pickup sensor, the method comprising the following steps:

[0010] The first excitation signal is provided to excite the measuring tube by the exciter, and the measuring tube is stabilized to vibrate at the first amplitude.

[0011] The vibration response of the measuring tube picked up by the sensor is used to obtain a first vibration response signal, and the vibration information of the measuring tube is obtained based on the first vibration response signal. The vibration information includes at least the first vibration frequency of the measuring tube. Furthermore, the vibration information may also include the velocity amplitude of the measuring tube, and the signal gain of the first excitation signal at this time can be obtained based on the velocity amplitude. The signal gain of the first excitation signal at this time is defined as the first signal gain.

[0012] A second excitation signal is provided, causing the exciter to excite the measuring tube under the combined action of the first and second excitation signals. A second signal gain is defined, the second excitation signal is configured to have a second signal gain, the second signal gain is fixed, and the second excitation signal is always out of phase with the first excitation signal by a preset phase.

[0013] The first excitation signal is adjusted and configured to follow the vibration response of the measuring tube picked up by the pickup sensor. A third signal gain is defined, which is the signal gain of the adjusted first excitation signal. The third signal gain is configured to satisfy the following conditions: the amplitude of the measuring tube is maintained at a second amplitude; the second amplitude is the same as or different from the first amplitude.

[0014] The vibration response of the measuring tube picked up by the sensor is used to obtain a second vibration response signal, and the second vibration frequency of the measuring tube is obtained based on the second vibration response signal;

[0015] Based on the first vibration frequency, the second vibration frequency, the second signal gain, the third signal gain, and the phase difference between the second excitation signal and the first excitation signal, calculate at least one of the following structural parameters: mass coefficient, stiffness coefficient, and damping coefficient.

[0016] In summary, the present application provides a method for diagnosing the structural parameters of a vibration-based measuring instrument. This method obtains the first vibration frequency of the measuring tube when its vibration state is stable, and additionally provides a second excitation signal whose phase differs from the first excitation signal by a preset angle. The first and second excitation signals are applied together to the measuring tube to obtain its second vibration frequency. The structural parameters of the measuring instrument under its current state are then calculated by combining the signal gains of the first and second excitation signals, as well as the phase difference between them.

[0017] Furthermore, the second excitation signal differs from the first excitation signal by a preset phase, and the preset phase θ satisfies the following relationship: -π < θ < π, and θ ≠ 0.

[0018] Furthermore, the second excitation signal either leads or lags behind the first excitation signal. Phase.

[0019] Furthermore, the gain of the second signal may be equal to or different from the gain of the first signal.

[0020] Furthermore, in response to the first vibration response signal being in a stable state, the first vibration frequency and the first signal gain are obtained.

[0021] Furthermore, in response to the second vibration response signal being in a stable state, the second vibration frequency of the measuring tube is obtained based on the second vibration response signal.

[0022] Furthermore, the mass coefficient and stiffness coefficient are calculated based on the first vibration frequency, the second vibration frequency, the signal gain of the second excitation signal, and the phase difference between the second excitation signal and the first excitation signal, respectively; the damping coefficient is calculated based on the signal gain of the second excitation signal, the signal gain of the adjusted first excitation signal, and the phase difference between the second excitation signal and the first excitation signal.

[0023] Furthermore, the structural parameters are calculated using the following formula:

[0024] In the formula, m is the mass coefficient, k is the stiffness coefficient, and c is the damping coefficient. This represents the signal gain of the second excitation signal. The average value of the first vibration frequency. ω3 is the signal gain of the adjusted first excitation signal, ω3 is the second vibration frequency, and θ is the phase difference between the second excitation signal and the first excitation signal.

[0025] Furthermore, the initial structural parameters of the metering instrument are obtained, and the current structural parameters of the metering instrument are compared with the initial structural parameters. If the offset of the current structural parameters of the metering instrument is greater than or equal to a preset threshold, the metering instrument is judged to be abnormal.

[0026] Furthermore, the structural parameters are converted to standard condition structural parameters, and the standard condition structural parameters are compared with the initial structural parameters to determine whether the measuring instrument is abnormal.

[0027] Secondly, this application provides a vibration-based measuring instrument, which applies the diagnostic method for the structural parameters of the vibration-based measuring instrument described above.

[0028] Furthermore, the measuring instrument is a Coriolis mass flow meter, or a density meter, or a viscosity meter.

[0029] Thirdly, this application provides a diagnostic device for the structural parameters of a vibration-based measuring instrument. The measuring instrument includes a measuring tube, a vibrator, and a pickup sensor. The device includes:

[0030] The vibration control module is used to provide a first excitation signal to cause the vibrator to excite the measuring tube, and the measuring tube is stabilized to vibrate at the first amplitude.

[0031] The acquisition module is used to pick up the vibration response of the measuring tube picked up by the sensor to obtain a first vibration response signal, and to obtain the vibration information of the measuring tube based on the first vibration response signal. The vibration information includes at least the first vibration frequency of the measuring tube.

[0032] The vibration control module is also used to provide a second excitation signal so that the exciter excites the measuring tube under the combined action of the first excitation signal and the second excitation signal. The second excitation signal is configured with a fixed signal gain and is always out of phase with the first excitation signal by a preset phase.

[0033] An amplitude holding module is used to adjust a first excitation signal, which is configured to follow the vibration response of the measuring tube picked up by the pickup sensor, and to adjust the signal gain of the first excitation signal so that the amplitude of the measuring tube is maintained at a second amplitude; the second amplitude may be the same as or different from the first amplitude.

[0034] The acquisition module is also used to pick up the vibration response of the measuring tube picked up by the sensor to obtain a second vibration response signal, and to obtain the second vibration frequency of the measuring tube based on the second vibration response signal;

[0035] The structural parameter calculation module is used to calculate at least one of the following types of structural parameters based on the first vibration frequency, the second vibration frequency, the signal gain of the second excitation signal, the signal gain of the adjusted first excitation signal, and the phase difference between the second excitation signal and the first excitation signal: mass coefficient, stiffness coefficient, and damping coefficient.

[0036] Fourthly, this application provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the method for diagnosing the structural parameters of a vibration-based metering instrument as described above.

[0037] Fifthly, this application provides a computer program product, including a computer program that, when executed by a processor, implements a method for diagnosing the structural parameters of a vibration-based metering instrument as described in any of the above claims. Attached Figure Description

[0038] Figure 1 is a flowchart illustrating a method for diagnosing the structural parameters of a vibration-based metering instrument according to an embodiment of this application.

[0039] Figure 2 shows an embodiment of this application providing an added and maintained lead first excitation signal. Schematic diagram of the second excitation signal in the phase;

[0040] Figure 3 shows an embodiment of this application providing an added, maintain-lag, first excitation signal. Schematic diagram of the second excitation signal in the phase;

[0041] Figure 4 is a schematic diagram of a second excitation signal provided in one embodiment of this application, which is added to maintain an arbitrary phase ahead of the first excitation signal. Detailed Implementation

[0042] The present application will be described in detail below with reference to the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present application. Any structural, methodological, or functional modifications made by those skilled in the art based on these embodiments are included within the protection scope of the present application.

[0043] To facilitate understanding, some parameters in this application will first be explained. The method for diagnosing the structural parameters of vibration-based metering instruments provided in this application can be applied to vibration-based metering instruments (such as Coriolis mass flow meters and density-viscosity meters). Vibration-based metering instruments typically include a measuring tube, a vibrator, and a pickup sensor. The vibrator is used to generate an excitation signal to drive the measuring tube to vibrate. Specifically, an excitation current acts on the vibrator, thereby generating an excitation signal; the pickup sensor is used to acquire the vibration response signal of the measuring tube, which is used to characterize the vibration state of the measuring tube.

[0044] In this application, gain is defined as the result of dividing the amplitude of the excitation force applied by the exciter to the measuring tube by the amplitude of the vibration velocity of the measuring tube, wherein the vibration velocity of the measuring tube is converted from the amplitude of the signal received by the sensor; damping ratio is defined as the ratio of the damping coefficient to the critical damping coefficient; stiffness is defined as the ability of the measuring tube to resist deformation.

[0045] When a vibration-based metering instrument starts up and stabilizes, its motion characteristics can be expressed by a single-degree-of-freedom vibration differential equation:

[0046] In the formula, For vibration velocity, Let x be the vibration acceleration, m be the vibration displacement, c be the mass coefficient, k be the damping coefficient, and G0 be the gain, which is the result of dividing the excitation force applied to the measuring tube by the vibration velocity amplitude of the measuring tube. The gain G0 can be obtained by receiving the sensor amplitude and the excitation current amplitude.

[0047] When the vibration-based metering instrument is in normal working condition and the amplitude reaches a stable state, there is the following equation about the damping coefficient: c=G0 (2);

[0048] In the formula, c and G0 have the same meaning as before.

[0049] Solving for x in Formula 1 yields:

[0050] In the formula, ω0 is the natural frequency. For ease of explanation, ω0 is named the first vibration frequency. Let ω0 be the initial phase, A be the amplitude of the displacement, and t be the duration of the recorded signal. The specific value of ω0 is:

[0051] In the formula, the meanings are the same as before, and m and k represent the mass coefficient and stiffness coefficient, respectively.

[0052] We can also obtain the expression for velocity:

[0053] Therefore, under steady-state conditions, the frequency of the received sensor signal is the natural frequency. The frequencies ω0[n] of N received sensor signals are continuously recorded over a period T0 (e.g., 10 s), along with the gain G0[n] of the excitation signal, where n is an integer from 0 to N-1 (e.g., if the signal frequency is calculated every 100 ms, then N = 100). The average value of ω0 can then be obtained.

[0054] It can also calculate the average value of the excitation signal gain over this period.

[0055] Based on the above signal processing principles, this application provides a method for diagnosing the structural parameters of a vibration-based metering instrument.

[0056] Firstly, this application provides a method for diagnosing the structural parameters of a vibration-based measuring instrument. The method is applied to a vibration-based measuring instrument, which includes a measuring tube, a vibrator, and a pickup sensor. Figure 1 is a flowchart illustrating the method for diagnosing the structural parameters of a vibration-based measuring instrument according to an embodiment of this application. As shown in Figure 1, the method includes the following steps:

[0057] Step S101: Provide a first excitation signal to excite the measuring tube by the exciter, and stabilize the measuring tube in vibration at the first amplitude.

[0058] Step S102: Pick up the vibration response of the measuring tube picked up by the sensor to obtain a first vibration response signal, and obtain the vibration information of the measuring tube based on the first vibration response signal. The vibration information includes at least the first vibration frequency of the measuring tube.

[0059] Furthermore, the vibration information may also include the velocity amplitude of the measuring tube, and the signal gain of the first excitation signal at this time can be obtained based on the velocity amplitude, and the signal gain of the first excitation signal at this time is defined as the first signal gain;

[0060] Step S103: Provide a second excitation signal so that the exciter excites the measuring tube under the combined action of the first excitation signal and the second excitation signal. The second excitation signal is configured to have a second signal gain, the second signal gain is fixed, and the second excitation signal always maintains a preset phase with the first excitation signal.

[0061] Step S104: Adjust the first excitation signal. The first excitation signal is configured to follow the vibration response of the measuring tube picked up by the pickup sensor. Adjust the gain of the first excitation signal to the third signal gain. The third signal gain is configured to satisfy the following condition: keep the amplitude of the measuring tube at the first amplitude.

[0062] In some embodiments, step S104 may involve adjusting a first excitation signal, which is configured to follow the vibration response of the measuring tube picked up by the pickup sensor, and adjusting the signal gain of the first excitation signal so that the amplitude of the measuring tube is maintained at a second amplitude; the second amplitude may be the same as or different from the first amplitude.

[0063] Step S105: Pick up the vibration response of the measuring tube picked up by the sensor to obtain the second vibration response signal, and obtain the second vibration frequency of the measuring tube based on the second vibration response signal;

[0064] Step S106: Based on the first vibration frequency, the second vibration frequency, the second signal gain, the third signal gain, and the phase difference between the second excitation signal and the first excitation signal, calculate at least one of the following structural parameters: mass coefficient, stiffness coefficient, and damping coefficient.

[0065] Based on the above description, this application provides a method for diagnosing the structural parameters of a vibration-based measuring instrument. It provides a first excitation signal to obtain the first vibration frequency of the measuring tube when the tube's vibration state is stable. It also provides a second excitation signal with a phase difference of a preset angle from the first excitation signal. The first and second excitation signals are applied together to the measuring tube to obtain its second vibration frequency. Based on the changes in the measuring tube's vibration frequency under the two states and the phase difference between the first and second excitation signals, the vibration system parameters of the vibration-based measuring instrument are calculated. This allows for comparison of the current vibration system parameters with the initial data, ensuring the measuring instrument's accuracy and preventing measurement errors.

[0066] The diagnostic method for structural parameters of vibration-based metering instruments provided in the embodiments of this application will be described in detail below.

[0067] In the method for diagnosing the structural parameters of a vibration-based metering instrument provided in this embodiment, the first vibration frequency and the first signal gain are obtained in response to the first vibration response signal being in a stable state.

[0068] Specifically, in step S102, the first vibration frequency and the first signal gain are obtained when the first vibration response signal is in a stable state. For ease of explanation, the first vibration frequency is denoted as ω0 and the first signal gain is denoted as G0.

[0069] Furthermore, the vibration response signal over a period of time can be recorded to calculate the average first vibration frequency and the average first signal gain. The average first vibration frequency is used as the first vibration frequency, and the average first signal gain is used as the first signal gain, thereby ensuring the accuracy of the vibration frequency and signal gain calculations.

[0070] In this embodiment of the application, the average value of the first vibration frequency is denoted as... Let the average gain of the first signal be denoted as... Furthermore, after converting the amplitude of the first vibration response signal into displacement amplitude, it is denoted as the first vibration displacement amplitude A, which is referred to as the first amplitude in this document (it should be noted that in some optional embodiments, the vibration information of the first vibration response signal may include velocity or acceleration amplitude, and the amplitude of the measuring tube can be controlled by the velocity or acceleration amplitude). When the measuring tube is in a stable working state, the average gain of the first signal is... and the average of the first vibration frequency Satisfy the following formula:

[0071] In the formula, the meanings of each parameter are the same as those above.

[0072] Example 1

[0073] Figure 2 shows an embodiment of this application providing an added and maintained lead first excitation signal. A schematic diagram of the second excitation signal in phase. As shown in Figure 2, as an optional implementation, in the method for diagnosing the structural parameters of a vibration-based metering instrument provided in this embodiment, the second excitation signal leads the first excitation signal. Phase.

[0074] Specifically, in step S103, a second excitation signal is provided, which leads the first excitation signal. Phase. Let the first excitation signal be d0. The first excitation signal d0 and the first vibration response signal always maintain the same frequency and phase. Add a signal that maintains a lead over the first excitation signal. The second excitation signal is denoted as d1, and its frequency is consistent with the frequency of the response signal. The gain of the second excitation signal is denoted as G1, and is set to remain constant.

[0075] In the formula, a1 is a constant greater than 0 (e.g., a1 = 5). This is the average value of the first signal gain of the first excitation signal mentioned above.

[0076] As explained above, the frequency and phase of the first excitation signal are always consistent with the second vibration response signal. When the phase of the second vibration response signal changes, the phase of the first excitation signal changes accordingly, while the second excitation signal always leads the second vibration response signal (or the first excitation signal). Phase. As shown in Figure 2, if the phase change of the first excitation signal d0 after a certain time period T1 is set to the position of the gray dashed line in Figure 2, then the second excitation signal d1 will maintain a leading position over the first excitation signal. The phase of the second excitation signal d1 is also adjusted accordingly to the position shown by the black dashed line in Figure 2, so that the second excitation signal d1 always maintains a phase lead over the first excitation signal d0. Furthermore, the initial phase information of the first excitation signal d0 can be obtained from the vibration information of the first vibration response signal.

[0077] In step S104, the gain of the first excitation signal d0 is adjusted to keep the amplitude A of the first vibration displacement of the measuring tube constant. Due to the presence of the second excitation signal d1, the gain of the first excitation signal d0 may change or remain unchanged. The gain of the first excitation signal d0 at this time is defined as the third signal gain. For ease of explanation, the third signal gain is denoted as...

[0078] In step S105, the second vibration response signal of the measuring tube is obtained under the combined action of the first excitation signal and the second excitation signal. In response to the second vibration response signal being in a stable state, the second vibration frequency of the measuring tube is obtained. For ease of explanation, the second vibration frequency is denoted as ω1.

[0079] After adding the second excitation signal d1, the expression for the vibration velocity of the measuring tube is:

[0080] In the formula, ω1 is the second vibration frequency. It should be noted that, due to the presence of the second excitation signal d1, the second vibration frequency ω1 and the first vibration frequency ω0 may be equal or not equal, so they are distinguished by different symbols. The initial phase of the vibration displacement (the initial phase of the vibration velocity is...) That is, vibration velocity leads vibration displacement. ).

[0081] The first excitation signal d0 is the excitation force signal required to maintain the displacement amplitude of the measuring tube at A, and can be written as:

[0082] In the formula, the meanings of each parameter are consistent with those in the previous text, that is, For the third signal gain, ω1 is the initial phase of the vibration displacement, and ω1 is the second vibration frequency.

[0083] The second excitation signal d1 is an additional sinusoidal excitation force, which can be written as:

[0084] In the formula, the meanings of each parameter are the same as those in the previous text.

[0085] Therefore, the excitation force on the measuring tube can be expressed by the following formula:

[0086] In the formula, F drive This represents the excitation force, measured in Newtons (Newtons). The meaning of ω1 is consistent with the above. Based on Newton's second law and Hooke's law, employing the assumption of viscous damping, and neglecting the influence of gravity, the differential equations of motion characteristics of the measuring tube can be derived:

[0087] After sorting, we get:

[0088] Therefore, if the first excitation signal d0 and the second excitation signal d1, after stabilizing the measuring tube, have:

[0089] And the system's natural frequency changes as follows:

[0090] Equation 18 can be transformed to obtain: mω1 2 -G1ω1-k=0 (19);

[0091] The second vibration frequency ω1 is positive, therefore it can be concluded that the second vibration frequency ω1 converges to:

[0092] Furthermore, if the second signal gain G1 is greater than 0, it can be noted that:

[0093] Therefore, the added second excitation signal will cause an upward step change in the vibration response frequency of the measuring tube. Before adding the second excitation signal, the vibration frequency is the natural frequency, which is determined by the mass coefficient and stiffness coefficient; after adding the second excitation signal, the vibration frequency or natural frequency changes, and this frequency is jointly determined by the mass coefficient, stiffness coefficient, and the gain of the second excitation signal, while the damping coefficient is determined by the gain of the real-time changing first excitation signal. Based on this analysis, combined with formulas 9-10, 17, and 19, the structural parameters can be obtained:

[0094] In the formula, m is the mass coefficient, k is the stiffness coefficient, c is the damping coefficient, and the remaining parameters are consistent with the above description. As an optional implementation method, in the structural parameter diagnosis method of vibration-based metering instruments provided in this embodiment, the structural parameters obtained above can be converted into structural parameters under standard conditions. For example, the measured stiffness coefficient k can be converted to the stiffness coefficient k' under standard conditions (such as standard temperature and standard pressure) based on the process parameters under the current test state.

[0095] As an optional implementation, the method for diagnosing the structural parameters of a vibration-based metering instrument provided in this embodiment further includes: obtaining the initial structural parameters of the metering instrument, comparing the current structural parameters of the metering instrument with the initial structural parameters, and determining that the metering instrument is abnormal in response to the offset of the current structural parameters of the metering instrument being greater than or equal to a preset threshold.

[0096] Specifically, based on the structural parameters obtained in the above description, a period of time T2 is recorded, that is, the time during which the second excitation signal d1 is maintained. Within the T2 period, P continuous results of mass coefficients m, stiffness coefficient k', and damping coefficient c are obtained. The results of these P mass coefficients are represented by m[0], m[2]... to m[P-1], the results of these P stiffness coefficients are represented by k'[0], k'[1]... to k'[P-1], and the results of these P damping coefficients are represented by c[0], c[1]... to c[P]. Therefore, the results of this diagnosis can be output as three parameters, namely the average mass coefficient... average stiffness coefficient Average damping coefficient

[0097] The initial average mass coefficient, average stiffness coefficient, and average damping coefficient of the measuring instrument are recorded as the initial mass coefficient m. ori Initial stiffness coefficient k ori Initial damping coefficient c ori The following parameters for the healthy state of a vibrational system can be defined: h = {h...} m ,h k ,h c The parameter is a three-element array, and its detailed calculation method is as follows:

[0098] In the formula, h m h represents the quality coefficient offset. k h represents the stiffness coefficient offset. c This indicates the damping coefficient offset; the other parameters are the same as described above.

[0099] For example, after obtaining the health state parameter h, in response to the stiffness coefficient offset h k The stiffness coefficient offset is greater than a certain preset threshold X1, for example, if the preset threshold X1 is set to 5%, when the stiffness coefficient offset h is greater than a certain preset threshold X1. k If the deviation is greater than 5%, the current metering instrument can be judged to be abnormal; or, in response to the damping coefficient deviation h c The damping coefficient deviation exceeds a preset threshold X2, for example, if the preset threshold X2 is set to 10%, then the damping coefficient deviation will be greater than a certain preset threshold X2. hc If the deviation is greater than 10%, the current metering instrument can be judged to be abnormal; or, in response to the mass coefficient deviation h m The deviation exceeds a certain preset threshold X3, for example, if the preset threshold X3 is set to 10%, when the quality coefficient offset h m If the percentage is greater than 10%, the current metering instrument can be judged to be abnormal.

[0100] Example 2

[0101] As another optional implementation, in the method for diagnosing the structural parameters of a vibration-based metering instrument provided in this embodiment, the second excitation signal lags behind the first excitation signal. Phase.

[0102] Specifically, in step S103, a second excitation signal is provided, which lags behind the first excitation signal. Phase. Let the first excitation signal be d0. The first excitation signal d0 and the first vibration response signal always maintain the same frequency and phase. Add a signal that lags behind the first excitation signal... The second excitation signal is then used, and the subsequent response signal is named the second vibration response signal. The first excitation signal and the vibration response signal maintain consistent frequency and phase. For ease of explanation, the second excitation signal in this embodiment is denoted as d2, and the frequency of the second excitation signal d2 is consistent with the frequency of the second vibration response signal. For ease of explanation, the gain of the second excitation signal in this embodiment is denoted as G2, and the gain G2 of the second excitation signal is set to remain constant.

[0103] In the formula, a2 is a constant greater than 0. G1 is the average gain of the first signal, and G2 is the gain of the second excitation signal.

[0104] As explained above, the frequency and phase of the first excitation signal always remain consistent with the vibration response signal. After the second excitation signal is added, when the phase of the second vibration response signal changes, the phase of the first excitation signal changes in accordance with the phase change of the second vibration response signal.

[0105] Figure 3 shows an embodiment of this application providing an added, maintain-lag, first excitation signal. A schematic diagram of the second excitation signal in phase. As shown in Figure 3, if the phase change of the first excitation signal d0 after a certain time period t is set to the position of the gray dashed line in Figure 3, then the second excitation signal d2 will remain behind the first excitation signal. The phase of the second excitation signal d2 is also adjusted accordingly to the position shown by the black dashed line in Figure 3, so that the second excitation signal d2 always lags behind the phase of the first excitation signal d0.

[0106] In step S104, the gain of the first excitation signal d0 is adjusted so that the displacement amplitude A of the measuring tube remains constant. Due to the presence of the second excitation signal d2, the gain of the first excitation signal d0 may be the same as or different from that when only the first excitation signal is present. Therefore, the gain of the first excitation signal d0 at this time is defined as the third signal gain. For ease of explanation, the third signal gain in this embodiment is denoted as...

[0107] After adding the second excitation signal d2, the expression for the vibration displacement x is:

[0108] In the formula, ω2 is the frequency of the vibration displacement or response signal. For ease of explanation, ω2 is named the second vibration frequency. It should be noted that, due to the presence of the second excitation signal d2, the second vibration frequency ω2 is not necessarily equal to the first vibration frequency ω0. Let be the initial phase of the vibration displacement. Then the expression for the velocity is:

[0109] The first excitation signal d0 is the excitation force signal required to maintain the vibration displacement amplitude, which can be written as:

[0110] The second excitation signal d2 should be an additional sinusoidal excitation force, which can be written as:

[0111] In the formula, as mentioned above, G2 is the gain of the second excitation signal. ω1 represents the initial phase of the vibration displacement, and ω2 represents the second vibration frequency.

[0112] Therefore, the excitation force on the measuring tube can be expressed by the following formula:

[0113] Similar to the above, using Oxford's second law and Hooke's law, and employing the assumption of viscous damping, we have the following differential equations describing the characteristics of the reaction motion:

[0114] Therefore, if the two excitation forces, the first excitation signal d0 and the second excitation signal d2, stabilize the amplitude of the measuring tube, then:

[0115] And the system's natural frequency changes as follows:

[0116] Equation 33, after simplification, yields: mω2 2 +G2ω2-k=0 (34);

[0117] Since the second vibration frequency ω2 is positive, it can be concluded that the second vibration frequency ω2 converges to:

[0118] Furthermore, if the second signal gain G2 is greater than 0, and considering that both the stiffness coefficient k and the mass coefficient m are positive, it can be noted that:

[0119] Therefore, the added second excitation signal will cause a downward step in the vibration response frequency of the measuring tube. Similar to Embodiment 1, before the second excitation signal is added, the vibration frequency is the natural frequency, which is determined by the mass coefficient and stiffness coefficient; after the second excitation signal is added, the vibration frequency or natural frequency changes, and this frequency is jointly determined by the mass coefficient, stiffness coefficient, and the gain of the second excitation signal, while the damping coefficient is determined by the gain of the real-time changing first excitation signal. Combining Equations 9, 25, 32, and 34, the vibration system parameters can be obtained:

[0120] The parameters in the formula have been described above and will not be repeated here.

[0121] Subsequent calculations can be performed following the same procedure described above to obtain the average mass. average stiffness Average Damping Furthermore, the current health status of the measuring instruments will be determined. This will not be elaborated upon further here.

[0122] Example 3

[0123] As another optional implementation, in the method for diagnosing the structural parameters of a vibration-based metering instrument provided in this embodiment, the second excitation signal differs from the first excitation signal by a preset phase. When the preset phase is greater than 0, the second excitation signal leads the first excitation signal; when the preset phase is less than 0, the second excitation signal lags behind the first excitation signal. The preset phase θ satisfies the following relationship:

[0124] -π<θ<π, and θ≠0.

[0125] Specifically, in step S103, a second excitation signal is provided, which differs from the first excitation signal by a preset phase. The preset phase θ satisfies the following relationship: -π < θ < π, and θ ≠ 0. The first excitation signal is denoted as d0. The first excitation signal d0 maintains the same frequency and phase as the vibration response signal. A second excitation signal with a preset phase difference from the first excitation signal is added. The vibration response signal is then named the second vibration response signal. For ease of explanation, the second excitation signal in this embodiment is denoted as d3, and the frequency of the second excitation signal d3 is consistent with the frequency of the second vibration response signal. For ease of explanation, the gain of the second excitation signal in this embodiment (defined as the second signal gain) is denoted as G3, and the gain G3 of the second excitation signal is set to remain constant.

[0126] In the formula, a3 is a constant greater than 0. The average gain of the first signal.

[0127] As described above, the frequency and phase of the first excitation signal are always consistent with the vibration response signal. When the phase of the vibration response signal changes, the phase of the first excitation signal changes accordingly. Figure 4 is a schematic diagram of adding a second excitation signal that maintains an arbitrary phase ahead of the first excitation signal according to an embodiment of this application. As shown in Figure 4, after a certain period of time, the phase change of the first excitation signal d0 is set to the position of the gray dashed line in Figure 4. Then, in order to maintain a phase difference of θ with the first excitation signal, the phase of the second excitation signal d3 is also adjusted accordingly to the position of the black dashed line in Figure 4, so that the second excitation signal d3 always maintains a phase difference of θ with the first excitation signal d0 or the response signal.

[0128] In step S104, the gain of the first excitation signal d0 is adjusted to keep the displacement amplitude A of the measuring tube constant. At this time, it is necessary to adjust the gain of the first excitation signal d0 so that the first excitation signal d0, together with the second excitation signal d3, keeps the amplitude of the vibration displacement of the measuring tube constant. Here, the gain of the first excitation signal d0 is defined as the third signal gain, that is, the signal gain of the adjusted first excitation signal. For ease of explanation, the third signal gain in this embodiment is denoted as... The frequency of the second excitation signal is denoted as ω3.

[0129] Similar to the above explanation, the differential equations describing the characteristics of the reaction motion are listed below:

[0130] Therefore, if the second excitation signal d3 and the first excitation signal d0 together stabilize the amplitude of the measuring tube, then:

[0131] And the system's natural frequency is changed to:

[0132] After rearranging Formula 41, the second excitation frequency ω3 satisfies the following equation: mω3 2 -G3ω3sinθ-k=0 (42);

[0133] Therefore, the second excitation frequency ω3 will converge to:

[0134] Since the preset phase θ≠0, a3>0, and the mass coefficient m>0 and stiffness coefficient k>0, ω3≠ω0 must exist. This indicates that due to the simultaneous existence of the two excitation forces d3 and d0, the natural frequency of the system will undergo a step change, and the direction of the change depends on the sign of θ.

[0135] Before adding the second excitation signal, the vibration frequency is the natural frequency, which is determined by the mass coefficient and stiffness coefficient. After adding the second excitation signal, the vibration frequency or natural frequency changes, and this frequency is jointly determined by the mass coefficient, stiffness coefficient, gain of the second excitation signal, and the preset phase difference θ between the second excitation signal and the vibration response signal. Simultaneously, the damping coefficient is jointly determined by the fixed gain of the second excitation signal, the preset phase difference θ between the second excitation signal and the vibration response signal, and the real-time changing gain of the first excitation signal. Combining formulas 9, 38, and 40, and the formula...

[0136] Equation 42 can be used to obtain the parameters of the vibration system:

[0137] The parameters in the formula have been described above and will not be repeated here.

[0138] Subsequent calculations can be performed following the same procedure described above to obtain the average mass. average stiffness Average Damping Furthermore, the current health status of the measuring instruments will be determined. This will not be elaborated upon further here.

[0139] In summary, this application provides a method for diagnosing the structural parameters of a vibration-based measuring instrument. It provides a first excitation signal to obtain the first vibration frequency of the measuring tube when the tube's vibration state is stable. It also provides a second excitation signal with a phase difference of a preset angle from the first excitation signal. The first and second excitation signals are applied together to the measuring tube to obtain its second vibration frequency. Based on the changes in the measuring tube's vibration frequency under the two states, and combined with the phase difference between the first and second excitation signals, the structural parameters of the vibration-based measuring instrument under its current state are calculated. The structural parameters under the current state are compared with the initial structural parameters to determine whether the measuring instrument exhibits any structural parameter abnormalities. This method diagnoses and provides early warnings for wear, corrosion, and wall adhesion, thereby improving the reliability of the measuring instrument's measurements.

[0140] It should be noted that while this application maintains a constant first vibration displacement amplitude when controlling the first excitation gain, it should be understood that this method is equally applicable to maintaining either the first vibration velocity amplitude or the first vibration acceleration amplitude. That is, in step S104, the "amplitude of the measuring tube" can be the first vibration displacement amplitude, or it can be selected as the velocity amplitude of the measuring tube, or the acceleration amplitude of the measuring tube.

[0141] Since the method presented in this paper essentially maintains the amplitude of the measuring tube unchanged, it will not affect the measurement of mass flow rate. Furthermore, the frequency step is a measurable quantity; when converting the frequency to density using conventional methods, it is only necessary to compensate for the step value back to its original value. Therefore, the method presented in this paper will not affect the measurement of density.

[0142] Secondly, this application also provides a vibration-based metering instrument that applies any of the structural parameter determination methods described above, which can improve the reliability of the metering instrument's measurements.

[0143] Thirdly, this application provides a diagnostic device for the structural parameters of a vibration-based measuring instrument. The measuring instrument includes a measuring tube, a vibrator, and a pickup sensor. The device includes:

[0144] The vibration control module is used to provide a first excitation signal to cause the vibrator to excite the measuring tube, and the measuring tube is stabilized to vibrate at the first amplitude.

[0145] The acquisition module is used to pick up the vibration response of the measuring tube picked up by the sensor to obtain a first vibration response signal, and to obtain the vibration information of the measuring tube based on the first vibration response signal. The vibration information includes at least the first vibration frequency of the measuring tube.

[0146] The vibration control module is also used to provide a second excitation signal so that the exciter excites the measuring tube under the combined action of the first excitation signal and the second excitation signal. The second excitation signal is configured with a fixed signal gain and is always out of phase with the first excitation signal by a preset phase.

[0147] An amplitude holding module is used to adjust a first excitation signal, which is configured to follow the vibration response of the measuring tube picked up by the pickup sensor, and to adjust the signal gain of the first excitation signal so that the amplitude of the measuring tube is maintained at a first amplitude.

[0148] The acquisition module is also used to pick up the vibration response of the measuring tube picked up by the sensor to obtain a second vibration response signal, and to obtain the second vibration frequency of the measuring tube based on the second vibration response signal;

[0149] The structural parameter calculation module is used to calculate at least one of the following types of structural parameters based on the first vibration frequency, the second vibration frequency, the signal gain of the second excitation signal, the signal gain of the adjusted first excitation signal, and the phase difference between the second excitation signal and the first excitation signal: mass coefficient, stiffness coefficient, and damping coefficient.

[0150] Fourthly, this application provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the method for diagnosing the structural parameters of a vibration-based metering instrument as described above.

[0151] Fifthly, this application provides a computer program product, including a computer program that, when executed by a processor, implements a method for diagnosing the structural parameters of a vibration-based metering instrument as described above.

[0152] It is understood that the term "exemplary" as used herein means "as an example, illustration, or description." Any embodiment described as "exemplary" is not necessarily preferred or superior to other embodiments and / or does not exclude features in combination with other embodiments. It should be understood that certain features of this application described in the context of a single embodiment for clarity may also be provided in combination in a single embodiment. Conversely, various features of this application described in the context of a single embodiment for clarity may also be provided individually or in any suitable combination or as part of any other described embodiment of this application.

[0153] The above-disclosed embodiments are merely preferred embodiments of this application, but are not intended to limit the scope of this application. Those skilled in the art will understand that any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and scope of this application and the appended claims are equivalent substitutions and still fall within the scope of the invention.

Claims

1. A method for diagnosing structural parameters of a vibration-based measuring instrument, the measuring instrument comprising a measuring tube, a vibrator, and a pickup sensor, characterized in that, The method includes the following steps: A first excitation signal is provided to excite the measuring tube by the exciter, and the measuring tube vibrates stably at a first amplitude. The pickup sensor picks up the vibration response of the measuring tube to obtain a first vibration response signal, and obtains the vibration information of the measuring tube based on the first vibration response signal. The vibration information includes at least a first vibration frequency of the measuring tube. A second excitation signal is provided, causing the exciter to excite the measuring tube under the combined action of the first excitation signal and the second excitation signal, wherein the second excitation signal is configured with a fixed signal gain, and the second excitation signal is always out of phase with the first excitation signal by a preset phase. The first excitation signal is adjusted to follow the vibration response of the measuring tube picked up by the pickup sensor, and the signal gain of the first excitation signal is adjusted so that the amplitude of the measuring tube is maintained at a second amplitude; the second amplitude may be the same as or different from the first amplitude. The pickup sensor picks up the vibration response of the measuring tube to obtain a second vibration response signal, and obtains the second vibration frequency of the measuring tube based on the second vibration response signal; Based on the first vibration frequency, the second vibration frequency, the signal gain of the second excitation signal, the signal gain of the adjusted first excitation signal, and the phase difference between the second excitation signal and the first excitation signal, calculate at least one of the following structural parameters: mass coefficient, stiffness coefficient, and damping coefficient.

2. The method for diagnosing the structural parameters of a vibration-based metering instrument according to claim 1, characterized in that, The second excitation signal differs from the first excitation signal by a preset phase, and the preset phase θ satisfies the following relationship: -π < θ < π, and θ ≠ 0.

3. The method for diagnosing the structural parameters of a vibration-based metering instrument according to claim 1, characterized in that, The second excitation signal leads or lags the phase of the first excitation signal by π2.

4. The method for diagnosing the structural parameters of a vibration-based metering instrument according to any one of claims 1 to 3, characterized in that, In response to the first vibration response signal being in a stable state, the first vibration frequency and the first signal gain are obtained, and the signal gain of the first excitation signal is the first signal gain.

5. The method for diagnosing the structural parameters of a vibration-based metering instrument according to any one of claims 1 to 4, characterized in that, In response to the second vibration response signal being in a stable state, the second vibration frequency of the measuring tube is obtained based on the second vibration response signal.

6. The method for diagnosing the structural parameters of a vibration-based metering instrument according to any one of claims 1 to 5, characterized in that, The mass coefficient and stiffness coefficient are calculated based on the first vibration frequency, the second vibration frequency, the signal gain of the second excitation signal, and the phase difference between the second excitation signal and the first excitation signal. The damping coefficient is calculated based on the signal gain of the second excitation signal, the signal gain of the adjusted first excitation signal, and the phase difference between the second excitation signal and the first excitation signal.

7. The method for diagnosing the structural parameters of a vibration-based metering instrument according to any one of claims 1 to 5, characterized in that, The structural parameters are calculated using the following formula: In the formula, m is the mass coefficient, k is the stiffness coefficient, and c is the damping coefficient. This represents the signal gain of the second excitation signal. The average value of the first vibration frequency. ω3 is the signal gain of the adjusted first excitation signal, ω3 is the second vibration frequency, and θ is the phase difference between the second excitation signal and the first excitation signal.

8. The method for diagnosing the structural parameters of a vibration-based metering instrument according to any one of claims 1 to 7, characterized in that, The initial structural parameters of the metering instrument are obtained, and the current structural parameters of the metering instrument are compared with the initial structural parameters. If the offset of the current structural parameters of the metering instrument is greater than or equal to a preset threshold, the metering instrument is determined to be abnormal.

9. The method for diagnosing the structural parameters of a vibration-based metering instrument according to claim 8, characterized in that, The structural parameters are converted to standard condition structural parameters, and the standard condition structural parameters are compared with the initial structural parameters to determine whether the measuring instrument is abnormal.

10. The method for diagnosing the structural parameters of a vibration-based metering instrument according to any one of claims 1 to 9, characterized in that, The second signal gain may be equal to or unequal to the first signal gain, the signal gain of the first excitation signal is the first signal gain, and the signal gain of the second excitation signal is the second signal gain.

11. A vibration-based measuring instrument, characterized in that, The metering instrument uses the method for diagnosing the structural parameters of a vibration-based metering instrument as described in any one of claims 1 to 10.

12. The vibration-based metering instrument according to claim 11, characterized in that, The metering instrument is a Coriolis mass flow meter, or a density meter, or a viscosity meter.

13. A diagnostic device for structural parameters of a vibration-based measuring instrument, the measuring instrument comprising a measuring tube, a vibrator, and a pickup sensor, characterized in that, The device includes: A vibration control module is used to provide a first excitation signal to cause the vibrator to excite the measuring tube, and the measuring tube is stabilized to vibrate at a first amplitude. The acquisition module is used to acquire the vibration response of the measuring tube picked up by the pickup sensor to obtain a first vibration response signal, and to obtain the vibration information of the measuring tube based on the first vibration response signal, wherein the vibration information includes at least a first vibration frequency of the measuring tube. The vibration control module is also used to provide a second excitation signal, so that the exciter excites the measuring tube under the combined action of the first excitation signal and the second excitation signal, wherein the second excitation signal is configured with a fixed signal gain, and the second excitation signal is always out of phase with the first excitation signal by a preset phase. An amplitude holding module is used to adjust the first excitation signal, which is configured to follow the vibration response of the measuring tube picked up by the pickup sensor, and to adjust the signal gain of the first excitation signal so that the amplitude of the measuring tube is maintained at a second amplitude; the second amplitude may be the same as or different from the first amplitude. The acquisition module is further configured to acquire the vibration response of the measuring tube picked up by the pickup sensor to obtain a second vibration response signal, and to acquire the second vibration frequency of the measuring tube based on the second vibration response signal; The structural parameter calculation module is used to calculate at least one of the following types of structural parameters based on the first vibration frequency, the second vibration frequency, the signal gain of the second excitation signal, the signal gain of the adjusted first excitation signal, and the phase difference between the second excitation signal and the first excitation signal: mass coefficient, stiffness coefficient, and damping coefficient.

14. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method for diagnosing the structural parameters of a vibration-based metering instrument as described in any one of claims 1 to 10.

15. A computer program product, characterized in that, It includes a computer program that, when executed by a processor, implements a method for diagnosing the structural parameters of a vibration-based metering instrument as described in any one of claims 1 to 10.

Images