Vibration-based measurement instrument and method for determining vibration parameters thereof
By using a signal decomposition method in the measuring instrument to calculate the damping ratio and other vibration parameters, the problems of complexity and cost in the prior art are solved, and high-precision real-time measurement is achieved.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- GOLDCARD HIGH TECH
- Filing Date
- 2025-12-08
- Publication Date
- 2026-06-18
AI Technical Summary
Existing vibration-based measuring instruments employ complex methods for determining vibration parameters, which consume computational resources and increase costs. Furthermore, they cannot achieve real-time flow measurement, thus affecting measurement accuracy.
By providing first and second excitation signals, the damping ratio of the measuring tube is calculated using the signal decomposition principle. Combined with signal gain and frequency, the vibration parameters of the measuring instrument, including mass, stiffness, and damping, are determined.
It improves the measurement accuracy of measuring instruments, avoids errors, ensures the structural health of measuring instruments, and reduces costs.
Smart Images
Figure CN2025140860_18062026_PF_FP_ABST
Abstract
Description
A vibration-based measuring instrument and a method for determining its vibration parameters.
[0001] This application claims priority to Chinese Patent Application No. 202411825372.8, filed on December 11, 2024, entitled "A Vibration-Based Measuring Instrument and a Method for Determining Vibration Parameters Thereof", the entire contents of which are incorporated herein by reference. Technical Field
[0002] This application relates to the field of intelligent diagnostics and signal processing technology for vibration-based measuring instruments, and in particular to a vibration-based measuring instrument and a method for determining its vibration parameters. Background Technology
[0003] Vibration parameters in vibration-based measuring instruments (including Coriolis mass flow meters and density / viscosity meters), such as stiffness, mass, and damping, directly affect the accuracy of measurement results like mass flow rate and density. For example, the calibration coefficient of a Coriolis mass flow meter (referred to as a Coriolis mass flow meter in this paper) is highly sensitive to stiffness. During use, it may suffer from pipe damage such as wear and corrosion, thus affecting its accuracy. Therefore, it is necessary to study intelligent diagnostic methods for vibration parameters in vibration-based measuring instruments.
[0004] In existing technologies, the determination of vibration parameters in vibration-based measuring instruments often employs additional filter design methods. This approach is complex, consumes computational resources allocated to flow rate or density calculations, and increases the cost of the measuring instrument due to the added filters. Furthermore, some vibration parameter measurement methods can affect real-time flow rate measurement, making simultaneous measurement impossible. Summary of the Invention
[0005] To address the shortcomings of existing technologies, the purpose of this application is to provide a method for determining the vibration parameters of a vibration-based measuring instrument. This application can determine the structural health status of the measuring instrument under its current condition and improve the accuracy of the measuring instrument's measurements.
[0006] To achieve the above objectives, this application adopts the following technical solution:
[0007] In a first aspect, this application provides a method for determining vibration parameters in a vibration-based measuring instrument. The method is applied to a Coriolis mass flow meter or a density-viscosity meter, etc. The vibration-based measuring instrument includes a measuring tube, a vibrator, and a pickup sensor. The method includes the following steps:
[0008] A first excitation signal is provided to cause the exciter to excite the measuring tube;
[0009] Receive the vibration response of the measuring tube picked up by the pickup sensor to obtain a first vibration response signal;
[0010] A second excitation signal is provided to excite the measuring tube by the exciter. The phase difference between the second excitation signal and the first excitation signal is a preset angle. The frequency and amplitude of the second excitation signal are fixed. After the second excitation signal is provided, the first excitation signal is removed or the amplitude of the first excitation signal is set to 0.
[0011] The vibration response of the measuring tube picked up by the pickup sensor under the drive of the second excitation signal is recorded to obtain the second vibration response signal;
[0012] The damping ratio of the measuring tube is calculated based on the amplitude change of the second vibration response signal and / or the phase difference change between the second vibration response signal and the second excitation signal.
[0013] In summary, this application provides a method for determining vibration parameters in a vibration-based measuring instrument. When the vibration state of the measuring tube is stable, a second excitation signal with a phase leading or lagging behind the first excitation signal by a preset angle is provided. The second vibration response signal at this time is then decomposed into a first decomposed signal and a second decomposed signal. The phase of the first decomposed signal is equal to that of the second excitation signal, and the second excitation signal maintains the amplitude of the first decomposed signal. Based on the changes in the second vibration response signal, the damping ratio of the vibration-based measuring instrument under the current state is calculated.
[0014] Furthermore, the method also includes: calculating the damping ratio of the measuring tube based on the amplitude change and / or phase difference change of the second vibration response signal, including:
[0015] The second vibration response signal is decomposed to obtain a first decomposed signal and a second decomposed signal, wherein the phase of the first decomposed signal is the same as that of the second excitation signal, and the second excitation signal maintains the amplitude of the first decomposed signal.
[0016] The damping ratio of the measuring tube is calculated based on the amplitude change of the second decomposed signal and / or the phase difference change between the second vibration response signal and the second excitation signal.
[0017] Furthermore, the method also includes: the second decomposed signal is synthesized from at least two sub-decomposed signals.
[0018] Furthermore, the method also includes: the initial phase difference between the second excitation signal and the first excitation signal is greater than or equal to 0° and less than or equal to 180°.
[0019] Furthermore, the method also includes: the phase of the second excitation signal leading or lagging behind the phase of the first excitation signal π.
[0020] Furthermore, the method also includes: the excitation current of the second excitation signal satisfies the following relationship:
[0021] In the formula, I0 represents the excitation current of the first excitation signal, A1 is equal to the amplitude of the first decomposed signal, and A0 represents the amplitude of the first vibration response signal.
[0022] Furthermore, the method also includes: before providing the second excitation signal, determining that the first vibration response signal of the measuring tube reaches a stable state under the excitation of the first excitation signal.
[0023] Furthermore, the method also includes: in response to the first vibration response signal reaching a stable state, obtaining the signal gain and signal frequency of the first vibration response signal based on the first vibration response signal;
[0024] Calculate at least one of the following types of vibration parameters based on the damping ratio, the signal gain, and the signal frequency:
[0025] Mass coefficient, stiffness coefficient, damping coefficient.
[0026] Furthermore, the method also includes: obtaining the initial vibration parameters of the vibration-based measuring instrument, comparing the current vibration parameters of the measuring instrument with the initial vibration parameters, and determining that the measuring instrument is abnormal in response to the offset of the current vibration parameters of the measuring instrument being greater than or equal to a preset threshold.
[0027] Secondly, this application provides a vibration-based measuring instrument that applies the method for determining vibration parameters in the vibration-based measuring instrument described in any of the above claims.
[0028] Furthermore, the measuring instrument is a Coriolis mass flow meter, or a density meter, or a viscosity meter. Attached Figure Description
[0029] Figure 1 is a waveform diagram illustrating the signal decomposition principle of this application;
[0030] Figure 2 is a waveform diagram of another signal decomposition principle of this application;
[0031] Figure 3 is a flowchart illustrating a method for determining the vibration parameters of a measuring instrument according to an embodiment of this application;
[0032] Figure 4 is a schematic diagram of a signal isosceles triangle decomposition method provided in an embodiment of this application;
[0033] Figure 5 is a schematic diagram of a signal inversion decomposition method provided in one embodiment of this application;
[0034] Figure 6 is a schematic diagram of a signal decomposition method provided in one embodiment of this application;
[0035] Figure 7 is a schematic diagram showing the change of the phase difference between the response signal and the second excitation signal over time in an isosceles triangle decomposition method provided in an embodiment of this application;
[0036] Figure 8 is a schematic diagram of the change of response signal amplitude over time in an isosceles triangle decomposition method provided in an embodiment of this application. Detailed Implementation
[0037] 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.
[0038] To facilitate understanding, some parameters in this application will be explained first. Vibration-based measuring instruments such as Coriolis mass flow meters or density-viscosity meters typically include a measuring tube, a vibrator, and a pickup sensor. The vibrator generates an excitation signal to drive the measuring tube to vibrate. Specifically, an excitation current acts on the vibrator, thereby generating the excitation signal; the pickup sensor acquires the vibration response signal of the measuring tube, which characterizes the vibration state of the measuring tube.
[0039] 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. It should be noted that in the embodiments of this application, the frequencies of the various signals used are consistent.
[0040] When the vibration-based measuring instrument is operating stably, the received vibration response signal of the test tube can be described by the following formula:
[0041]
[0042] In the formula, A0 represents the amplitude of the received vibration response signal, and ω represents the frequency of the vibration response signal. Let represent the initial phase of the vibration response signal, and t represent the duration of signal recording. This vibration response signal can be decomposed into the superposition of two signals with the same frequency (i.e., frequency ω) but different amplitudes and phases, which can be described by the following formula:
[0043] In the formula, A1 represents the amplitude of one of the decomposed signals, and its phase is... A2 represents the amplitude of the other signal obtained from the decomposition, and its phase is... Therefore, the right side of formula (2) can be further expanded as follows:
[0044] Comparing the left side of formula (2) and the right side of formula (3), we can see that the amplitude and phase of the two decomposed signals should satisfy the following relationship:
[0045] If the amplitude and phase of one of the decomposed signals are known, for example, A1 and θ1 are known, then we can conclude that:
[0046] For example, Figure 1 shows an example of decomposing a vibration response signal into two signals, namely, the vibration response signal is decomposed into the superposition of two signals with a phase difference of 90° and equal amplitude. In Figure 1, the vibration response signal is represented in yellow, and the two decomposed signals are represented in blue and red, respectively. Figure 2 shows another example of decomposing a vibration response signal into two signals, namely, the vibration response signal is decomposed into the superposition of two signals with the same frequency and amplitude as the original vibration response signal, and the amplitudes of the two decomposed signals are also equal to the amplitude of the original vibration response signal. In Figure 2, the vibration response signal is represented in yellow, and the two decomposed signals are represented in blue and red, respectively.
[0047] Based on the above-mentioned signal decomposition principle, this application provides a method for determining vibration parameters in a vibration-based measuring instrument.
[0048] Firstly, this application provides a method for determining vibration parameters in a vibration-based measuring instrument. This method is applied to Coriolis mass flow meters or density-viscosity meters, as shown in Figure 3. The method for determining vibration parameters in a vibration-based measuring instrument in this embodiment specifically includes the following steps:
[0049] Step S101: Provide a first excitation signal to excite the vibrator to vibrate the measuring tube;
[0050] Step S102: Receive the vibration response of the measuring tube picked up by the sensor to obtain the first vibration response signal;
[0051] Step S103: Provide a second excitation signal to excite the exciter's measuring tube. The phase difference between the second excitation signal and the first excitation signal is a preset angle. The frequency and amplitude of the second excitation signal are fixed. After providing the second excitation signal, remove the first excitation signal or set the amplitude of the first excitation signal to 0.
[0052] Step S104: Record the vibration response of the measuring tube picked up by the sensor under the drive of the second excitation signal to obtain the second vibration response signal;
[0053] It should be noted that at any given moment, the measuring tube exhibits only one vibration response state, which is captured by the pickup sensor. For ease of explanation, this application defines the vibration response captured by the pickup sensor during the phase when the first excitation signal is applied as the first vibration response signal; and defines the vibration response captured by the pickup sensor during the phase after the second excitation signal is provided as the second vibration response signal.
[0054] Step S105: Calculate the damping ratio of the measuring tube based on the amplitude change of the second vibration response signal and / or the phase difference change between the second vibration response signal and the second excitation signal.
[0055] This application provides a method for determining the vibration parameters of a vibration-based measuring instrument. By providing a first excitation signal and a second excitation signal, the vibration response signal of the measuring tube under the action of the two excitation signals is obtained. Based on the signal decomposition principle, the damping ratio of the measuring tube in the measuring instrument is calculated according to the changes in the amplitude and / or phase difference of the response signal. Based on the damping ratio of the measuring tube, the vibration system parameters of the measuring instrument are calculated. The vibration system parameters of the measuring instrument in the current state can be compared with the data at the time of manufacture to ensure the measurement accuracy of the measuring instrument and avoid measurement errors.
[0056] The method for determining the vibration parameters of the vibration-based measuring instrument provided in this embodiment will be described in detail below.
[0057] In the method for determining vibration parameters of the vibration-based measuring instrument provided in this embodiment, before providing the second excitation signal, it is first determined that the first vibration response signal of the measuring tube reaches a stable state under the excitation of the first excitation signal. As mentioned above, vibration-based measuring instruments include Coriolis mass flow meters and density-viscosity meters, etc. The Coriolis mass flow meter will be used as an example below.
[0058] At this time, record the average frequency f0, average gain G0, average amplitude V0, and average excitation current I0 of the first vibration response signal within t0. When operating stably at the natural frequency, the vibration differential equation of the Coriolis mass flowmeter can be described by the following equation:
[0059] In the formula, For vibration velocity, Let x be the vibration acceleration, G be the vibration displacement, m be the equivalent mass, k be the equivalent stiffness, and c be the damping coefficient. Define ω0 as the operating frequency obtained by the Coriolis mass flow meter under stable conditions; therefore, ω0 is the natural frequency of the measuring tube, hence the following formula: G0 = c (9);
[0060] In formulas (8) and (9), all parameters have the same meaning as before.
[0061] In step S103, a second excitation signal is provided that differs from the first excitation signal by a preset angle in phase. The second excitation signal leads or lags the first excitation signal by a preset angle θ1 in phase, and the frequency and amplitude of the second excitation signal are fixed. The frequency of the second excitation signal is the same as that of the first excitation signal.
[0062] In step S105, the second vibration response signal is decomposed into a first decomposed signal and a second decomposed signal, wherein the phase of the first decomposed signal is configured to be the same as that of the second excitation signal, and the second excitation signal needs to maintain the amplitude of the first decomposed signal.
[0063] Example 1
[0064] For example, this application provides a signal decomposition method using an isosceles triangle, decomposing a first vibration response signal into a first decomposed signal and a second decomposed signal. The phase of the first decomposed signal is the same as that of the second excitation signal, and the second excitation signal must maintain the amplitude of the first decomposed signal. Specifically, the amplitude of the excitation signal is related to the magnitude of the excitation current. In this embodiment, a fixed-magnitude excitation current is provided. For ease of explanation, this second excitation current is labeled I1. In the formula, I0 represents the excitation current of the first excitation signal, A1 is the amplitude of the first decomposed signal, and A0 represents the amplitude of the first vibration response signal. Furthermore, the phase of the second excitation signal provided in this application leads the initial phase θ1 of the second vibration response signal at the initial moment. For ease of explanation, the phase of the second excitation signal is denoted as... As shown in Figure 4, vector This represents the instant at the end of the first vibration response signal, which has an initial phase. It can also be viewed as the initial state of the second vibration response signal; vector This represents the first decomposed signal. The phase and the second vibration response signal initial phase Compared to the leading θ1, the first decomposed signal The amplitude A1 and The amplitude A0 is the same; vector This represents the second decomposed signal. For ease of explanation, the second decomposed signal... The amplitude is denoted by A2, the second decomposed signal. phase with This indicates that the second decomposition signal is... The phase and the second vibration response signal initial phase Compared to lagging behind θ2, the formula can be expressed as follows:
[0065] The phase of the first decomposed signal is configured to be consistent with the second excitation signal. The amplitude of the excitation current I0 remains the same as the current amplitude corresponding to the first excitation signal, and this amplitude is fixed, thus the amplitude of the first decomposed signal is fixed and will not decay over time. As time progresses, the amplitude of the second vibration response signal will first gradually decrease and then slowly recover. At this time, the phase difference ψ between the second excitation signal and the second vibration response signal... t It will also gradually approach 0. Since the amplitude of the first decomposed signal is fixed, and no excitation is applied to the second decomposed signal, the amplitude of the second decomposed signal will gradually decrease. Furthermore, the second decomposed signal only exhibits a change in amplitude and does not produce a change in phase difference with the first excitation signal. The amplitude change of the second decomposed signal is defined as b. t According to geometric relationships, b t Satisfy the following formula:
[0066] The relationship between the phase convergence of the second excitation signal and the second vibration response signal can be expressed by the following formula:
[0067] Define a function f1(t) with the following expression:
[0068] The rate of change of f1(t) is related to the damping ratio ζ, so we use f1′(t) instead. It represents the rate of change of f1(t) from t1 to the next time t2, and the relationship between this value and the damping ratio is expressed as follows:
[0069] In addition, we need to note the following relationship between the damping ratio and other vibration parameters:
[0070] In addition to formula 11-14, which is based on the phase difference ψ t We can calculate the damping ratio based on the change in signal amplitude, or we can calculate it based on the change in signal amplitude. From the geometric relationships in Figure 5, we have:
[0071] Based on this equation, we can obtain:
[0072] Note that in formula 17 at b t This holds true until the amplitude decreases to half of the initial value (i.e., A2). If the amplitude decreases to less than half of the initial value, the positive sign before the square root on the right side of Formula 17 should be changed to a negative sign. Therefore, b t The response amplitude A is reduced to half of its initial value.t Satisfy the following formula:
[0073] The left side of Formula 18 represents the ratio of the real-time amplitude of the second decomposed signal to its initial value. Unlike the vibration equation Formula 7, since no excitation is applied to the second decomposed signal, the corresponding vibration equation for this decomposed signal is:
[0074] Solving this second-order differential equation yields the amplitude variation law of the second decomposed signal:
[0075] The damping ratio ζ is defined as described above, and ω0 is the natural frequency.
[0076] Define a sum and response amplitude A t The relevant function g1(t) has the following expression:
[0077] We use g1′(t) to represent the rate of change of g1(t), that is... It represents the rate of change of the value of g1(t) from time t1 to the next time t2. The damping ratio ζ can be easily calculated from the rate of change of g1(t):
[0078] Example 2
[0079] As shown in Figure 5, as an optional implementation, this application also provides a signal decomposition method with inverse phase decomposition, wherein the phase of the second excitation signal leads or lags the phase of the first excitation signal π. According to the above description, the amplitude of the excitation signal is related to the magnitude of the excitation current. In this embodiment, a fixed-magnitude excitation current I1 is provided. When the amplitude of the excitation current I1 of the second excitation signal is equal to but out of phase with the excitation current I0 corresponding to the first excitation signal, the amplitude of the first decomposed signal is consistent with the amplitude of the first vibration response signal, but its phase is out of phase with the first vibration response signal. The amplitude of the second excitation signal is fixedly represented as A0. When decomposing the first vibration response signal, there exists a decomposed signal with the same amplitude as the first vibration response signal but opposite in direction. For ease of understanding, as shown in Figure 5, the first vibration response signal... Decomposed into the first decomposition signal Second decomposition signal First decomposition signal With the first vibration response signal Out of phase, i.e., the first decomposed signal Phase leading by π, first decomposed signal The amplitude of the second decomposed signal is the same as that of the first vibration response signal, both being A0; therefore, according to the vector decomposition principle, the second decomposed signal... With the first vibration response signal In phase, and the second decomposed signal The amplitude is 2A0.
[0080] The phase of the first decomposed signal is configured to be consistent with the second excitation signal, and the magnitude of the excitation current I0 remains unchanged compared to the excitation current corresponding to the first excitation signal. That is, the amplitude of the second excitation signal is fixed to the amplitude of the first excitation signal, thus the amplitude of the first decomposed signal is fixed and will not decay over time. Since the amplitude of the first decomposed signal is fixed, and no excitation is applied to the second decomposed signal, the amplitude of the second decomposed signal will gradually decrease. At this time, the phase difference ψ between the second excitation signal and the second vibration response signal... t π will be maintained initially. Once the amplitude of the second decomposed signal decreases to A0, ψ... t It will become 0, although according to ψ t The damping ratio is difficult to calculate due to the change in amplitude, but it can be calculated based on the characteristics of the change in signal amplitude. The calculation process is similar to that described above and will not be elaborated here.
[0081] It should be noted that the amplitude of the first decomposed signal may or may not be equal to the amplitude of the first vibration response signal.
[0082] Example 3
[0083] As an optional implementation, the method for determining the vibration parameters of the Coriolis mass flow meter provided in this embodiment can be implemented by decomposing the signal into arbitrary angles and amplitudes.
[0084] Specifically, the phase difference between the second excitation signal and the first excitation signal can be greater than or equal to 0°, and less than or equal to 180°; the signal decomposition principle described above also applies. The excitation current I1 of the second excitation signal is configured as follows:
[0085] In the formula, I0 represents the excitation current of the first excitation signal, A1 represents the amplitude required for the first decomposed signal, and A0 represents the amplitude of the first vibration response signal. When performing signal decomposition, the magnitude of the excitation current of the second excitation signal is determined based on the amplitude of the first decomposed signal.
[0086] As shown in Figure 6, the vibration response signal Decomposed into the first decomposition signal Second decomposition signal Among them, the first decomposition signal With the amplitude A1 fixed, the second vibration response signal With the first decomposition signal The initial phase difference between them is θ1, and the second decomposed signal No excitation was applied, second decomposition signal The amplitude gradually decreases, at which point the second excitation signal... Second vibration response signal phase difference ψ t It will gradually decrease to 0, and then the phase difference ψ can be used to determine the relationship. t The damping ratio is calculated based on the changing characteristics of the damping ratio. The calculation process is the same as described above and will not be repeated here.
[0087] Furthermore, in this embodiment, the signal is decomposed into two decomposed signals. One of the two decomposed signals can be further decomposed according to the signal decomposition principle. For example, the second decomposed signal mentioned above can be further decomposed into at least two sub-decomposed signals.
[0088] According to the above description, the method for determining vibration parameters in the vibration-based measuring instrument provided in this application, when the first vibration response signal reaches a stable state, obtains the damping ratio by applying the principle of signal decomposition and adjusting the phase of the excitation signal, based on the characteristics of the phase difference change. Based on the damping ratio and combined with the signal gain and signal frequency, at least one of the following types of vibration parameters can be calculated: mass coefficient, stiffness coefficient, and damping coefficient.
[0089] Specifically, based on the damping ratio calculated in the above description, and the obtained gain and frequency of the first vibration response signal, combined with formulas 8, 9, 14, and 15, the phase difference ψ between the second excitation signal and the second vibration response signal can be obtained. t The formula for obtaining the vibration parameters from the changes in is expressed as follows:
[0090] In the formula, consistent with the previous text, m represents the mass coefficient, k represents the stiffness coefficient, c represents the damping coefficient, and f1'(t) represents the phase difference ψ. t The relevant function f1(t) is the rate of change over time, G0 represents the mean gain, and ω0 is the natural frequency of the measuring tube. Figure 7 shows the phase difference ψ between the second excitation signal and the response signal in the isosceles triangle decomposition method. t Example of changes over time, with a preset angle in the example. Damping ratio ζ = 0.00005.
[0091] Similarly, by combining formulas 8, 9, 22, and 15, we can obtain the following formula for calculating the vibration parameters based on the change in the amplitude At of the second vibration response signal:
[0092] In the formula, g1'(t) is the rate of change of the function g1(t) related to the response amplitude mentioned above with time. Figure 8 shows the response signal amplitude A in the isosceles triangle decomposition method. t Example of changes over time, with a preset angle in the example. Damping ratio ζ = 0.00005.
[0093] Based on the vibration parameters obtained under the current test conditions, the stiffness coefficient k obtained under the current test conditions is converted into the stiffness coefficient k' of the Coriolis mass flow meter under the standard conditions. That is, the standard condition stiffness coefficient is obtained by taking into account the current pressure and temperature compensation. For example, the stiffness coefficient is converted into the stiffness coefficient at a standard atmospheric pressure and 0℃. The standard condition stiffness coefficient k' can reflect the structural health of the Coriolis mass flow meter to a certain extent.
[0094] As an optional implementation, the method for determining the vibration parameters of the Coriolis mass flow meter provided in this embodiment further includes: obtaining the initial vibration parameters of the Coriolis mass flow meter, comparing the current vibration parameters of the Coriolis mass flow meter with the initial vibration parameters, and determining that the Coriolis mass flow meter is abnormal if the offset of the current vibration parameters of the Coriolis mass flow meter is greater than or equal to a preset threshold.
[0095] Specifically, based on the vibration parameters obtained in the above description, and combined with the initial vibration parameters of the Coriolis mass flow meter, the following parameters reflecting the health status of the measuring tube are defined: h m h k h c and h ζ The specific definition is as follows:
[0096] In the formula, m represents the current mass coefficient of the Coriolis mass flow meter, k' represents the current standard state stiffness coefficient of the Coriolis mass flow meter, c represents the current damping coefficient of the Coriolis mass flow meter, ζ represents the current damping ratio of the Coriolis mass flow meter, m0 represents the initial mass coefficient of the Coriolis mass flow meter, k0 represents the initial standard state stiffness coefficient of the Coriolis mass flow meter, c0 represents the initial damping coefficient of the Coriolis mass flow meter, ζ0 represents the initial damping ratio of the Coriolis mass flow meter, and h m h represents the quality coefficient offset. k h represents the stiffness coefficient offset. c This indicates the damping coefficient offset, and h ζ This indicates the damping ratio offset.
[0097] For example, in response to 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. kIf the deviation is greater than 5%, the Coriolis mass flow meter can be considered malfunctioning; or, in response to the damping coefficient offset h... c The damping ratio offset h is greater than a certain preset threshold X2. ζ If the damping coefficient offset is greater than a certain preset threshold X3, for example, if preset thresholds X2 and X3 are set to 10%, then when the damping coefficient offset h c Greater than 10% and damping ratio offset h ζ If the deviation is greater than 10%, the Coriolis mass flow meter can be considered abnormal; or, in response to the mass coefficient offset h m The damping ratio offset is greater than a certain preset threshold X4 and the damping ratio offset h ζ If the deviation exceeds a certain preset threshold X3, for example, if the preset thresholds X3 and X4 are set to 10%, then when the quality coefficient offset h m Greater than 10% and damping ratio offset h ζ If the percentage is greater than 10%, the Coriolis mass flow meter can be considered to be malfunctioning.
[0098] In summary, the method for determining vibration parameters of a resonance-based measuring instrument provided in this application, under the condition that the vibration state of the measuring tube is stable, decomposes the first vibration response signal into a first decomposed signal and a second decomposed signal with preset angles and amplitudes. The first excitation signal is removed and a second excitation signal is provided to maintain the amplitude and phase of the first decomposed signal. Based on the phase difference change characteristics between the second vibration response signal and the first decomposed signal (or the second excitation signal), the damping ratio of the measuring instrument under the current state is calculated, the vibration parameters of the measuring instrument under the current state are determined, and the vibration parameters of the measuring instrument under the current state are compared with the initial vibration parameters to determine whether the measuring instrument has malfunctioned, thereby improving the measurement accuracy of the resonance-based measuring instrument.
[0099] Secondly, this application also provides a Coriolis mass flow meter that applies any of the vibration parameter determination methods described above, which can improve the measurement accuracy of the Coriolis mass flow meter.
[0100] 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.
[0101] 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 this application.
Claims
1. A method for determining vibration parameters in a vibration-based measuring instrument, the vibration-based 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 cause the exciter to excite the measuring tube; Receive the vibration response of the measuring tube picked up by the pickup sensor to obtain a first vibration response signal; A second excitation signal is provided to excite the measuring tube by the exciter. The phase difference between the second excitation signal and the first excitation signal is a preset angle. The frequency and amplitude of the second excitation signal are fixed. After the second excitation signal is provided, the first excitation signal is removed or the amplitude of the first excitation signal is set to 0. The vibration response of the measuring tube picked up by the pickup sensor under the drive of the second excitation signal is recorded to obtain the second vibration response signal; The damping ratio of the measuring tube is calculated based on the amplitude change of the second vibration response signal and / or the phase difference change between the second vibration response signal and the second excitation signal.
2. The method for determining vibration parameters in a vibration-based measuring instrument according to claim 1, characterized in that, The damping ratio of the measuring tube is calculated based on the amplitude and / or phase difference changes of the second vibration response signal, including: The second vibration response signal is decomposed to obtain a first decomposed signal and a second decomposed signal, wherein the phase of the first decomposed signal is the same as that of the second excitation signal, and the second excitation signal maintains the amplitude of the first decomposed signal. The damping ratio of the measuring tube is calculated based on the amplitude change of the second decomposed signal and / or the phase difference change between the second vibration response signal and the second excitation signal.
3. The method for determining vibration parameters in a vibration-based measuring instrument according to claim 2, characterized in that, The second decomposed signal is synthesized from at least two sub-decomposed signals.
4. The method for determining vibration parameters in a vibration-based measuring instrument according to claim 1, characterized in that, The initial phase difference between the second excitation signal and the first excitation signal is greater than or equal to 0° and less than 180°.
5. The method for determining vibration parameters in a vibration-based measuring instrument according to claim 1, characterized in that, The phase of the second excitation signal leads or lags behind the phase of the first excitation signal π.
6. The method for determining vibration parameters in a vibration-based measuring instrument according to claim 1, characterized in that, The excitation current of the second excitation signal satisfies the following relationship: In the formula, I0 represents the excitation current of the first excitation signal, A1 has the same amplitude as the first decomposed signal, and A0 represents the amplitude of the first vibration response signal.
7. The method for determining vibration parameters in a vibration-based measuring instrument according to claim 1, characterized in that, The method further includes: Before providing the second excitation signal, it is first determined that the first vibration response signal of the measuring tube reaches a stable state under the excitation of the first excitation signal.
8. The method for determining vibration parameters in a vibration-based measuring instrument according to claim 1, characterized in that, The method further includes: After the first vibration response signal reaches a stable state, the signal gain and signal frequency of the first vibration response signal are obtained based on the first vibration response signal. Calculate at least one of the following types of vibration parameters based on the damping ratio, the signal gain, and the signal frequency: Mass coefficient, stiffness coefficient, damping coefficient.
9. The method for determining vibration parameters in a vibration-based measuring instrument according to claim 8, characterized in that, The initial vibration parameters of the vibration-based measuring instrument are obtained, and the current vibration parameters of the measuring instrument are compared with the initial vibration parameters. If the offset of the current vibration parameters of the measuring instrument is greater than or equal to a preset threshold, the measuring instrument is determined to be abnormal.
10. A vibration-based measuring instrument, characterized in that, The vibration-based measuring instrument uses the method for determining the vibration parameters of the measuring instrument as described in any one of claims 1 to 9.
11. The vibration-based measuring instrument according to claim 10, characterized in that, The measuring instrument is a Coriolis mass flow meter, or a density meter, or a viscosity meter.