Resonant string sensor in-phase feedback excitation method and system

Abstract

The application discloses a vibrating string sensor in-phase feedback excitation method and system, comprising the following steps: firstly, frequency measurement is performed on the sine wave signal to obtain the vibration frequency of the oscillation signal generated by the vibrating string sensor; then, a phase self-adaptive compensation algorithm is used to calculate the phase delay between the excitation signal and the oscillation signal of the vibrating string sensor caused by filtering and other reasons according to the measured vibration frequency; the sending time of the excitation signal in the next period can be determined according to the calculated phase delay; when the detection time reaches the sending time, a sine wave excitation signal with the same frequency and the same phase is generated according to the vibration frequency to excite the vibrating string sensor, so that the phase difference between the excitation signal and the sensor oscillation signal is eliminated; and the cycle is repeated, so that the oscillation amplitude of the vibrating string sensor in the detection process can be avoided from being weakened.

Description

Technical Field

[0001] This invention relates to the technical field of measurement using electricity or magnetism, and specifically to a method and system for in-phase feedback excitation of a vibrating wire sensor. Background Technology

[0002] A vibrating wire sensor is a resonant sensor that uses a taut metal string as its sensing element. Once the string length is determined, the change in its natural vibration frequency characterizes the magnitude of the tension in the string. Through a corresponding measurement circuit, an electrical signal related to the tension can be obtained. With the development of structural monitoring technology, vibrating wire sensor data acquisition has gradually evolved from static to dynamic acquisition.

[0003] Patent application CN106802161A discloses an excitation method for a vibrating wire sensor, and specifically discloses the method of selecting the optimal excitation method from a variety of high-voltage pulse excitation methods and a variety of low-voltage pulse excitation methods for measurement based on the excitation voltage.

[0004] However, in this technical solution, a filter amplifier is used to amplify and filter the vibration signal acquired from the vibrating wire sensor, and a low-frequency scanning circuit is used to output excitation. The introduction of the filter amplifier and the low-frequency scanning circuit causes a significant phase delay in the final read vibration signal. When the phase delay falls within a certain range, the resulting excitation voltage causes the vibration amplitude generated by the vibrating wire sensor to gradually decrease, eventually leading to the sensor ceasing to oscillate. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention proposes a method and system for in-phase feedback excitation of a vibrating wire sensor. This method can eliminate the phase difference between the excitation signal and the sensor's oscillation signal, thus preventing a decrease in the oscillation amplitude of the vibrating wire sensor. The specific technical solution is as follows:

[0006] In a first aspect, a method for in-phase feedback excitation of a vibrating wire sensor is provided, wherein in a first implementable manner of the first aspect, the method includes:

[0007] The voltage signal fed back by the vibrating wire sensor under the excitation pulse of the previous cycle is obtained, and the voltage signal is measured to obtain the vibration frequency of the oscillation signal generated by the vibrating wire sensor.

[0008] The phase delay between the excitation signal and the oscillation signal of the vibrating wire sensor is calculated based on the vibration frequency using a phase adaptive compensation algorithm, and the excitation pulse transmission time of the next cycle is determined by the phase delay.

[0009] When the detection time reaches the excitation pulse transmission time, an excitation signal with the same frequency and phase is generated according to the vibration frequency to excite the vibrating wire sensor.

[0010] In conjunction with the first implementable method of the first aspect, in the second implementable method of the first aspect, measuring the voltage signal includes:

[0011] The voltage signal fed back by the vibrating wire sensor is filtered and amplified to convert the voltage signal into a sinusoidal voltage signal with low harmonics;

[0012] The sinusoidal voltage signal is shaped into a rectangular wave signal with the same frequency and amplitude;

[0013] The vibration frequency is obtained by measuring the frequency of the rectangular wave signal.

[0014] In conjunction with the first possible implementation of the first aspect, in the third possible implementation of the first aspect, the phase adaptive compensation algorithm includes:

[0015] Using the corresponding phase delay function, the phase delay of the circuit unit applied in each stage of the excitation process is calculated according to the vibration frequency.

[0016] The phase delay between the excitation signal and the oscillation signal is calculated by combining the phase delay corresponding to each of the circuit modules.

[0017] In conjunction with the third possible implementation of the first aspect, in the fourth possible implementation of the first aspect, the circuit unit includes a filtering and amplification unit for filtering and amplifying the voltage signal, and a smoothing and filtering unit for smoothing and filtering the excitation signal.

[0018] In conjunction with the fourth possible implementation of the first aspect, in the fifth possible implementation of the first aspect, the filtering and amplification module is a second-order Butterworth filter.

[0019] Secondly, a vibrating wire sensor in-phase feedback excitation system is provided, wherein in a first implementable embodiment of the second aspect, it includes:

[0020] The frequency measurement module is configured to acquire the voltage signal fed back by the vibrating wire sensor under the excitation pulse of the previous cycle, and to measure the voltage signal to obtain the vibration frequency of the oscillation signal generated by the vibrating wire sensor.

[0021] The excitation compensation module is configured to calculate the phase delay between the excitation signal and the oscillation signal of the vibrating wire sensor based on the vibration frequency using a phase adaptive compensation algorithm, and determine the excitation pulse transmission time of the next cycle through the phase delay.

[0022] When the detection time reaches the excitation pulse transmission time, an excitation signal with the same frequency and phase is generated according to the vibration frequency to excite the vibrating wire sensor.

[0023] In conjunction with the first possible implementation of the second aspect, in the second possible implementation of the second aspect, the frequency measurement module includes:

[0024] The filtering and amplification unit is configured to filter and amplify the voltage signal fed back by the vibrating wire sensor, so as to convert the voltage signal into a sinusoidal voltage signal with low harmonics.

[0025] The signal shaping unit is configured to shape a sinusoidal voltage signal into a rectangular wave signal with the same frequency and amplitude.

[0026] The frequency measurement unit is configured to measure the rectangular wave signal to obtain the vibration frequency.

[0027] In conjunction with the second possible implementation of the second aspect, in the third possible implementation of the second aspect, the filtering and amplification unit uses a second-order Butterworth filter for filtering.

[0028] In conjunction with the first possible implementation of the second aspect, in the fourth possible implementation of the second aspect, the incentive compensation module includes:

[0029] The compensation calculation unit is configured to calculate the phase delay based on the vibration frequency using a phase adaptive compensation algorithm, and to determine the excitation pulse transmission time of the next cycle through the phase delay;

[0030] The excitation generation unit is configured to generate a sinusoidal digital signal with the same frequency and phase according to the vibration frequency when the detection time reaches the excitation pulse transmission time.

[0031] An analog-to-digital converter is configured to convert the sinusoidal digital signal into an analog voltage signal;

[0032] The power amplification and filtering unit is configured to amplify and smooth the analog voltage signal, and output a corresponding excitation signal to excite the vibrating wire sensor.

[0033] In conjunction with the fourth possible implementation of the second aspect, in the fifth possible implementation of the second aspect, the power amplification and filtering unit uses an LC low-frequency filter for filtering.

[0034] Beneficial Effects: By employing the in-phase feedback excitation method and system for vibrating wire sensors of this invention, the vibration frequency of the oscillation signal generated by the vibrating wire sensor under the excitation signal of the previous cycle can be obtained by measuring the frequency of the sinusoidal signal. Through a phase adaptive compensation algorithm, the phase delay between the excitation signal and the oscillation signal of the vibrating wire sensor caused by filtering and other factors can be calculated based on the measured vibration frequency. The transmission time of the excitation signal for the next cycle can be determined based on the calculated phase delay. When the detection time reaches the transmission time, a sinusoidal excitation signal with the same frequency and phase can be generated to excite the vibrating wire sensor, thereby eliminating the phase difference between the excitation signal and the sensor's oscillation signal. This cycle is repeated to prevent the oscillation amplitude of the vibrating wire sensor from weakening during the detection process. Attached Figure Description

[0035] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the specific embodiments will be briefly described below. In all the drawings, the elements or parts are not necessarily drawn to scale.

[0036] Figure 1 A flowchart of a method for in-phase feedback excitation of a vibrating wire sensor according to an embodiment of the present invention;

[0037] Figure 2 This is a system schematic diagram of a vibrating wire sensor in-phase feedback excitation system provided in an embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram showing the comparison of voltage signals, sine wave signals, rectangular wave signals, and excitation signals. Detailed Implementation

[0039] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0040] like Figure 1 The flowchart shown is for an in-phase feedback excitation method for a vibrating wire sensor. This excitation method includes:

[0041] Step 1: Obtain the sinusoidal signal generated by the vibrating wire sensor under the excitation signal of the previous cycle, and measure the frequency of the sinusoidal signal to obtain the vibration frequency of the vibrating wire sensor.

[0042] Step 2: Calculate the phase delay between the excitation signal and the oscillation signal of the vibrating wire sensor using a phase adaptive compensation algorithm based on the vibration frequency, and determine the transmission time of the excitation signal in the next cycle based on the phase delay.

[0043] When the detection time reaches the excitation pulse transmission time, an excitation signal with the same frequency and phase is generated according to the vibration frequency to excite the vibrating wire sensor.

[0044] Specifically, the vibrating wire sensor generates a corresponding voltage signal under the action of an excitation signal. This voltage signal is then filtered and amplified to obtain a sinusoidal signal. First, the frequency of this sinusoidal signal can be measured to obtain the vibration frequency of the oscillation signal generated by the vibrating wire sensor under the action of the excitation signal in the previous cycle. Then, a phase adaptive compensation algorithm can be used to calculate the phase delay between the excitation signal and the oscillation signal of the vibrating wire sensor caused by filtering and other factors, based on the measured vibration frequency.

[0045] The calculated phase delay determines the transmission time of the excitation signal for the next cycle. When the detection time reaches the transmission time, a sinusoidal excitation signal of the same frequency and phase as the vibration frequency is generated to excite the vibrating wire sensor, thereby eliminating the phase difference between the excitation signal and the sensor's oscillation signal. This cycle is repeated to prevent the oscillation amplitude of the vibrating wire sensor from weakening during the detection process.

[0046] In this embodiment, optionally, step 1, measuring the frequency of the sine wave signal, includes: shaping the sine wave signal into a rectangular wave signal with the same frequency and amplitude. Specifically, before measuring the sine wave signal, the sine wave signal can be shaped by a signal shaping circuit to convert the sine wave into a rectangular wave signal with the same frequency and amplitude for subsequent frequency measurement.

[0047] In this embodiment, optionally, the phase adaptive compensation algorithm includes:

[0048] Using the corresponding phase delay function, the phase delay corresponding to each stage in the excitation process is calculated based on the vibration frequency.

[0049] The phase delay between the excitation signal and the oscillation signal is calculated by combining the phase delays corresponding to each stage.

[0050] Specifically, when calculating the phase delay between the excitation signal and the oscillation signal, the phase delay caused by each stage can be calculated based on the measured vibration frequency and the phase delay functions corresponding to all stages that cause phase delay during the excitation process. For example, the phase delay caused by the filtering and amplification stage of the voltage signal can be calculated using the phase delay function corresponding to the filtering and amplification stage. Finally, by combining the phase delays corresponding to all stages that cause delay, the phase delay between the excitation signal and the oscillation signal can be calculated.

[0051] In this embodiment, optionally, the phase adaptive compensation algorithm includes:

[0052] The phase delay function corresponding to the filtering and amplification stage of the voltage signal, and the phase delay function corresponding to the smoothing and filtering stage of the excitation signal.

[0053] Specifically, the phase adaptive compensation algorithm includes a phase delay function corresponding to the voltage signal filtering and amplification stage, and a phase delay function corresponding to the excitation signal smoothing and filtering stage. The filter used in the voltage signal filtering and amplification stage is a second-order Butterworth filter, and its corresponding phase delay function is:

[0054] ;

[0055] in, It is a constant. The cutoff frequency, , The frequency is the vibration frequency.

[0056] Considering that the filter used in the voltage signal filtering and amplification stage in this embodiment needs to be a low-pass filter, the phase delay function corresponding to the voltage signal filtering and amplification stage is:

[0057] .

[0058] The smoothing filtering stage of the excitation signal can use an LC low-frequency filter, whose corresponding phase delay function is:

[0059] ;

[0060] in, The coil resistance of the vibrating wire sensor, The inductor of the LC low-frequency filter, The capacitor is for the LC low-frequency filter.

[0061] Finally, the phase delay functions corresponding to each stage can be combined to calculate the phase delay between the excitation signal and the oscillation signal. The specific calculation formula is as follows:

[0062] .

[0063] It should be understood that this embodiment only uses the filtering and amplification stage of the voltage signal and the smoothing and filtering stage of the excitation signal as examples for illustration, but the present invention is not limited to these, and may also include the calculation of the phase delay of other stages in the excitation process. It should also be understood that this embodiment only uses a second-order Butterworth filter and an LC low-frequency filter as examples for illustration, but the present invention is not limited to these, and may also include other filters and their corresponding phase delay functions.

[0064] like Figure 3As shown, after calculating the phase delay between the excitation signal and the oscillation signal, the transmission time of the excitation signal in the next cycle can be determined based on the initial time, vibration frequency, and phase delay of the sinusoidal signal generated under the action of the excitation signal in the previous cycle. Specifically:

[0065] ;

[0066] ;

[0067] in, The period of the sine wave signal, The phase delay between the excitation signal and the oscillation signal, To determine the start time of the second cycle of the acquired sine wave signal, This refers to the time when the excitation signal is sent.

[0068] When the detection time reaches the sending time At that time, a frequency of can be generated. Furthermore, the excitation signal, which is in phase with the oscillation signal, excites the vibrating wire sensor to vibrate, thereby eliminating the phase difference between the excitation signal and the sensor's oscillation signal.

[0069] like Figure 2 The diagram shown is a schematic of the in-phase feedback excitation system for a vibrating wire sensor. The excitation system includes:

[0070] The filtering and amplification module is configured to filter and amplify the voltage signal generated by the vibrating wire sensor under the excitation signal of the previous cycle to obtain a sine wave signal with smaller harmonics.

[0071] An adaptive compensation module is configured to measure the frequency of the sinusoidal signal to obtain the vibration frequency of the vibrating wire sensor;

[0072] The phase delay between the excitation signal and the oscillation signal of the vibrating wire sensor is calculated based on the vibration frequency using a phase adaptive compensation algorithm, and the transmission time of the excitation pulse in the next cycle is determined by the phase delay.

[0073] When the detection time reaches the transmission time, the adaptive compensation module generates an excitation digital signal with the same frequency and phase according to the vibration frequency.

[0074] An analog-to-digital converter module is configured to convert the excitation digital signal into an analog voltage signal;

[0075] The power amplification and filtering module is configured to amplify and smooth the analog voltage signal.

[0076] Specifically, the excitation system includes a filtering and amplification module, an adaptive compensation module, an analog-to-digital conversion module, and a power amplification and filtering module. The filtering and amplification module filters and amplifies the voltage signal generated by the vibrating wire sensor under the excitation signal of the previous cycle, obtaining a sinusoidal signal with lower harmonics. The adaptive compensation module measures the frequency of the sinusoidal signal, thereby determining the vibration frequency of the oscillation signal generated by the vibrating wire sensor.

[0077] The adaptive compensation module can calculate the phase delay between the excitation signal and the oscillation signal of the vibrating wire sensor caused by the filtering and amplification module, power amplification and filtering module, etc., based on the vibration frequency, and determine the sending time of the excitation pulse in the next cycle, thereby eliminating the phase difference between the excitation signal and the sensor oscillation signal.

[0078] When the detection time reaches the transmission time of the next cycle's excitation pulse, the adaptive compensation module immediately outputs an excitation digital signal that is in phase and frequency with the oscillation signal. The analog-to-digital converter (ADC) converts the excitation digital signal output by the adaptive compensation module into an analog voltage signal. After being amplified and smoothed by the power amplification and filtering module, the analog voltage signal is transmitted to the vibrating wire sensor coil, exciting the vibrating wire sensor to vibrate. This cycle repeats, preventing the oscillation amplitude of the vibrating wire sensor from weakening during the detection process.

[0079] In this embodiment, optionally, the filtering and amplification module includes a second-order Butterworth filter. The Butterworth filter has a flat amplitude-frequency characteristic, suitable for applications requiring a wide operating frequency range for various types of vibrating wire sensors. Furthermore, the second-order Butterworth filter is relatively simple and reliable to implement, and its stopband attenuation meets requirements.

[0080] In this embodiment, optionally, the second-order Butterworth filter is a low-pass filter. This allows for the filtering out of high-frequency harmonics in the excitation signal and the effects of high-frequency noise in the line.

[0081] In this embodiment, optionally, a signal shaping module is also included, configured to convert the sinusoidal signal into a constant-amplitude rectangular wave signal of the same frequency, and the adaptive compensation module performs frequency measurement on the constant-amplitude rectangular wave signal to obtain the vibration frequency of the vibrating wire sensor.

[0082] Specifically, after the voltage signal obtained from the vibrating wire sensor is processed by the filtering and amplification module, the filtering and amplification module can send the processed sine wave signal to the signal shaping module. The signal shaping module can shape the sine wave signal into a square wave signal of the same frequency with equal amplitude, so that the subsequent adaptive supplementation module can perform frequency measurement.

[0083] In this embodiment, optionally, the adaptive compensation module includes:

[0084] The frequency measurement unit is configured to measure the frequency of the sinusoidal signal to obtain the vibration frequency of the vibrating wire sensor;

[0085] The phase compensation unit is configured to calculate the phase delay between the excitation signal and the oscillation signal of the vibrating wire sensor based on the vibration frequency using a phase adaptive compensation algorithm, and determine the transmission time of the next cycle excitation pulse through the phase delay. When the detection time reaches the transmission time, it generates an excitation digital signal with the same frequency and phase based on the vibration frequency.

[0086] The excitation control unit is configured to control the operating timing of the frequency measurement unit and the phase compensation unit.

[0087] Specifically, the adaptive compensation module includes a frequency measurement unit, a phase compensation unit, and an excitation control unit. The frequency measurement unit measures the frequency of the rectangular wave output by the signal shaping module to determine the vibration frequency of the oscillation signal generated by the vibrating wire sensor. The excitation control unit controls the timing of the phase compensation unit and the frequency measurement unit.

[0088] The phase compensation unit can calculate the phase delay between the oscillation signal and the excitation signal caused by the filtering and amplification modules, power amplification and filtering modules, etc., based on the vibration frequency measured by the frequency measurement unit, and determine the transmission time of the excitation signal in the next cycle based on the phase delay. When the detection time reaches the transmission time of the excitation signal, the phase compensation unit will immediately generate an excitation digital signal that is in phase and has the same frequency as the oscillation signal.

[0089] In this embodiment, optionally, the power amplification and filtering module includes an LC low-frequency filter.

[0090] Specifically, the digital excitation signal generated by the phase compensation unit is converted into an analog voltage signal by the analog-to-digital converter. Since the excitation signal requires a certain amount of power, a passive filter such as an LC filter can be used to smooth the analog voltage signal. The smoothed analog voltage signal can then excite the vibrating wire sensor coil, thereby generating a magnetic force that drives the steel string inside the vibrating wire sensor to resonate for detection.

[0091] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A method for in-phase feedback excitation of a vibrating wire sensor, characterized in that, include: The sine wave signal generated by the vibrating wire sensor under the excitation signal of the previous cycle is obtained, and the frequency of the sine wave signal is measured to obtain the vibration frequency of the vibrating wire sensor. The phase delay between the excitation signal and the oscillation signal of the vibrating wire sensor is calculated based on the vibration frequency using a phase adaptive compensation algorithm, and the transmission time of the excitation signal in the next cycle is determined by the phase delay. When the detection time reaches the excitation signal transmission time, an excitation signal with the same frequency and phase is generated according to the vibration frequency to excite the vibrating wire sensor. The phase adaptive compensation algorithm includes: Using the corresponding phase delay function, the phase delay corresponding to each stage in the excitation process is calculated based on the vibration frequency. The phase delay between the excitation signal and the oscillation signal is calculated by combining the phase delays corresponding to each stage, and the specific calculation formula is as follows: ； in, The coil resistance of the vibrating wire sensor, The inductor of the LC low-frequency filter For the capacitor of the LC low-frequency filter, It is a constant. The cutoff frequency, , The frequency is the vibration frequency.

2. The in-phase feedback excitation method for a vibrating wire sensor according to claim 1, characterized in that, Frequency measurement of a sine wave signal includes: shaping the sine wave signal into a rectangular wave signal with the same frequency and amplitude.

3. A vibrating wire sensor in-phase feedback excitation system, characterized in that, include: The filtering and amplification module is configured to filter and amplify the voltage signal generated by the vibrating wire sensor under the excitation signal of the previous cycle to obtain a sine wave signal; An adaptive compensation module is configured to measure the frequency of the sinusoidal signal to obtain the vibration frequency of the vibrating wire sensor; The phase delay between the excitation signal and the oscillation signal of the vibrating wire sensor is calculated based on the vibration frequency using a phase adaptive compensation algorithm, and the transmission time of the excitation signal in the next cycle is determined by the phase delay. When the detection time reaches the transmission time, the adaptive compensation module generates an excitation digital signal with the same frequency and phase according to the vibration frequency. An analog-to-digital converter module is configured to convert the excitation digital signal into an analog voltage signal; A power amplification and filtering module is configured to amplify and smooth the analog voltage signal. The phase adaptive compensation algorithm includes: Using the corresponding phase delay function, the phase delay corresponding to each stage in the excitation process is calculated based on the vibration frequency. The phase delay between the excitation signal and the oscillation signal is calculated by combining the phase delays corresponding to each stage, and the specific calculation formula is as follows: ； in, The coil resistance of the vibrating wire sensor, The inductor of the LC low-frequency filter For the capacitor of the LC low-frequency filter, It is a constant. The cutoff frequency, , The frequency is the vibration frequency.

4. The in-phase feedback excitation system for a vibrating wire sensor according to claim 3, characterized in that, The filtering and amplification module includes a second-order Butterworth filter.

5. The in-phase feedback excitation system for a vibrating wire sensor according to claim 4, characterized in that, The second-order Butterworth filter is a low-pass filter.

6. The in-phase feedback excitation system for a vibrating wire sensor according to claim 3, characterized in that, It also includes a signal shaping module, configured to convert the sinusoidal signal into a constant-amplitude rectangular wave signal of the same frequency, and the adaptive compensation module performs frequency measurement on the constant-amplitude rectangular wave signal to obtain the vibration frequency of the vibrating wire sensor.

7. The in-phase feedback excitation system for a vibrating wire sensor according to claim 3, characterized in that, The adaptive compensation module includes: The frequency measurement unit is configured to measure the frequency of the sinusoidal signal to obtain the vibration frequency of the vibrating wire sensor; The phase compensation unit is configured to calculate the phase delay between the excitation signal and the oscillation signal of the vibrating wire sensor based on the vibration frequency using a phase adaptive compensation algorithm, and determine the transmission time of the next cycle excitation pulse through the phase delay. When the detection time reaches the transmission time, it generates an excitation digital signal with the same frequency and phase based on the vibration frequency. The excitation control unit is configured to control the operating timing of the frequency measurement unit and the phase compensation unit.

8. The in-phase feedback excitation system for a vibrating wire sensor according to claim 3, characterized in that, The power amplification and filtering module includes an LC low-frequency filter.

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