Stay cable force measuring device and method

Abstract

The invention discloses an inhaul cable force measuring device and method. The inhaul cable force measuring device comprises a data acquisition device and a data processing device. The data acquisition device is mounted on the inhaul cable of the to-be-detected structure and is used for acquiring an original data signal when the inhaul cable vibrates; and the data processing device is electrically connected with the data acquisition device and is used for acquiring the original data signal and amplifying the signal component of the corresponding frequency in the original data signal according to a preset frequency band, obtaining the fundamental frequency of the inhaul cable after frequency extraction, and finally calculating the cable force of the inhaul cable according to the fundamental frequency of the inhaul cable and the incidence relation between the fundamental frequency of the inhaul cable and the cable force. The stay cable force measuring device provided by the invention has the characteristics of high measuring precision, low error and the like.

Description

Technical Field

[0001] The present invention relates to the measurement of cable forces of bridge stay cables, and particularly to a device and method for measuring cable forces of stay cables. Background Art

[0002] Traditionally, when measuring cable forces, the frequency method is generally adopted. However, the frequency method mainly relies on an acceleration sensor to capture the vibration data of the stay cable, and then software is used to collect and perform FFT (Fast Fourier Transform) to obtain the vibration spectrum. By analyzing the peak values in the spectrum, the fundamental vibration frequency of the stay cable can be determined, and the cable force can be calculated accordingly. However, the existing frequency method faces challenges in the software identification of the fundamental frequency. The main problems are that the software has a large error, the acquisition period is long, and when the environmental excitation is weak, the signal-to-noise ratio of the signals collected by the conventional method is low, and it is difficult to obtain stable frequency information through data signal processing. At the same time, the data processing period is long. These factors together result in a long frequency identification period and low accuracy of the conventional method, and further lead to calculation errors of the cable force.

[0003] In addition, there is also the permanent anchoring method used to measure cable forces. However, this method is relatively difficult to install, and it can only provide long-term monitoring at the end of the stay cable after installation before the stay cable is suspended. Therefore, its use has great limitations and cannot be flexibly arranged.

[0004] Furthermore, for the tension measurement method, since it constructs a force triangle based on the deformation in the vertical direction and the radial tension in the middle section of the stay cable through the principle of force decomposition, and then calculates the radial cable force. Although this method does not require prior installation, it has defects such as large measurement error. Summary of the Invention

[0005] In order to overcome the deficiencies of the prior art, one of the purposes of the present invention is to provide a device for measuring cable forces of stay cables, which can solve the problems of inaccurate measurement and large error in the existing measurement of cable forces of stay cables.

[0006] Another purpose of the present invention is to provide a method for measuring cable forces of stay cables, which can solve the problems of inaccurate measurement and large error in the existing measurement of cable forces of stay cables.

[0007] One of the purposes of the present invention is achieved by adopting the following technical solutions:

[0008] A cable force measuring device, the cable force measuring device includes a data acquisition device and a data processing device; wherein, the data acquisition device is installed on the cable of the structure to be measured, and is used to acquire the original data signal when the cable vibrates; the data processing device is electrically connected to the data acquisition device, and is used to acquire the original data signal and amplify and extract the signal components corresponding to the frequency in the original data signal according to a preset frequency band to obtain the fundamental frequency of the cable, and finally calculate the cable force according to the fundamental frequency of the cable and the correlation between the fundamental frequency of the cable and the cable force.

[0009] Further, the data acquisition device is an acceleration sensor or a vibration sensor; wherein, when the data acquisition device is an acceleration sensor, it is used to acquire the acceleration signal of the cable and then obtain the original data signal of the cable vibration according to the acceleration signal; when the data acquisition device is a vibration sensor, it is used to acquire the vibration signal of the cable and then obtain the original data signal of the cable vibration according to the vibration signal.

[0010] Further, the data processing device includes a main control chip, a signal amplification circuit, a frequency extraction circuit and an analog-to-digital conversion module; wherein, the input end of the signal amplification circuit is electrically connected to the data acquisition device, and the output end is electrically connected to the input end of the frequency extraction circuit; the output end of the frequency extraction circuit is electrically connected to the main control chip through the analog-to-digital conversion module;

[0011] The signal amplification circuit is used to amplify the signal components in the original data signal whose frequencies meet the preset frequency band according to the preset frequency band, so as to send the amplified original data signal to the frequency extraction circuit;

[0012] The frequency extraction circuit is used to extract the frequency of the amplified original data signal and then send it to the analog-to-digital conversion module so that the analog-to-digital conversion module converts the original data signal after frequency extraction into a digital signal and sends it to the main control chip;

[0013] The main control chip is used to obtain the frequency information of the digital signal according to the digital signal and obtain the fundamental frequency of the cable according to the frequency information, and then calculate the cable force according to the fundamental frequency of the cable and the corresponding relationship between the fundamental frequency of the cable and the cable force.

[0014] Further, the signal amplification circuit includes a resonant circuit or an active band-pass filter amplification circuit.

[0015] Further, the signal amplification circuit includes a first resistor, a second resistor, a third resistor, a first capacitor, a second capacitor, and a first operational amplifier; a first end of the first resistor is electrically connected to the data acquisition device, and a second end thereof is electrically connected to an inverting input end of the first operational amplifier through the second capacitor; a sensor signal source is further connected between the data acquisition device and the first end of the first resistor; a first end of the second resistor is grounded, and a second end thereof is connected between the second end of the first resistor and the second capacitor; a first end of the second capacitor is connected between the first resistor and the second capacitor, and a second end thereof is electrically connected to an output end of the first operational amplifier; a first end of the third resistor is connected between the second capacitor and the inverting input end of the first operational amplifier, and a second end thereof is connected between the first capacitor and the output end of the first operational amplifier; a non-inverting input end of the first operational amplifier is grounded; an output end of the first operational amplifier is electrically connected to an output end of the frequency extraction circuit; the first resistor, the second resistor, and the third resistor are programmable resistors.

[0016] Further, the frequency extraction circuit includes a first differentiating circuit, a second differentiating circuit, an inverting circuit, and a dividing circuit; wherein, an input end of the first differentiating circuit is electrically connected to an output end of the signal amplification circuit, and an output end of the first differentiating circuit is electrically connected to an input end of the second differentiating circuit; an output end of the second differentiating circuit is electrically connected to an input end of the inverting circuit; an output end of the inverting circuit is electrically connected to a first input end of the dividing circuit, and a second input end of the dividing circuit is electrically connected to the output end of the signal amplification circuit; an output end of the dividing circuit is electrically connected to the main control chip through the analog-to-digital conversion module;

[0017] The first differentiating circuit is configured to perform differentiating processing on the amplified original data signal and send it to the second differentiating circuit, so that the second differentiating circuit performs second differentiating processing on the differentiated original data signal; the inverting circuit is configured to invert the original data signal after the second differentiating processing and input it into the dividing circuit, so that the dividing circuit divides the inverted original data signal by the amplified original data signal and then inputs it into the analog-to-digital conversion module for analog-to-digital conversion;

[0018] The main control chip is configured to obtain the converted digital signal through the analog-to-digital conversion module, obtain frequency information based on the digital signal, and further calculate the fundamental frequency of the cable according to the frequency information.

[0019] Further, the first differential circuit includes a third capacitor, a fourth resistor, a fifth resistor, and a second operational amplifier; the second differential circuit includes a fourth capacitor, a sixth resistor, a seventh resistor, and a third operational amplifier; the inverting circuit includes a fifth capacitor, an eighth resistor, a ninth resistor, and a fourth operational amplifier; the division circuit includes a sixth capacitor, a tenth resistor, an eleventh resistor, a fifth operational amplifier, and a multiplier;

[0020] One end of the third capacitor is electrically connected to the output end of the signal amplification circuit, and the other end is electrically connected to the inverting input end of the second operational amplifier; one end of the fourth resistor is connected between the third capacitor and the inverting input end of the second operational amplifier, and the other end is electrically connected to the output end of the second operational amplifier; the non-inverting input end of the second operational amplifier is grounded;

[0021] The output end of the second operational amplifier is electrically connected to the inverting input end of the third operational amplifier through the fourth capacitor; one end of the seventh resistor is grounded, and the other end is electrically connected to the non-inverting input end of the third operational amplifier; one end of the sixth resistor is connected between the fourth capacitor and the inverting input end of the third operational amplifier, and the other end is electrically connected to the output end of the third operational amplifier;

[0022] The output end of the third operational amplifier is also electrically connected to the inverting input end of the fourth operational amplifier through the fifth capacitor; one end of the ninth resistor is grounded, and the other end is electrically connected to the non-inverting input end of the fourth operational amplifier; one end of the eighth resistor is connected between the fifth capacitor and the inverting input end of the fourth operational amplifier, and the other end is electrically connected to the output end of the fourth operational amplifier;

[0023] The output end of the fourth operational amplifier is electrically connected to the inverting input end of the fifth operational amplifier through the sixth capacitor; one end of the eleventh resistor is grounded, and the other end is electrically connected to the non-inverting input end of the fifth operational amplifier; one end of the tenth resistor is connected between the sixth capacitor and the inverting input end of the fifth operational amplifier, and the other end is electrically connected to the first end of the multiplier; the second end of the multiplier is connected between the signal amplifier and the third capacitor, and the second end is electrically connected to the output end of the fifth operational amplifier.

[0024] Further, the formula for the corresponding relationship between the fundamental frequency of the cable and the cable force is:

[0025] T = 4ml 2 f 2 (1);

[0026] where, T is the cable force, m is the cable linear density, l is the length between the cable anchorage points, and f is the fundamental frequency of the cable.

[0027] Further, the main control chip is further configured to match the fundamental frequency of the cable with a preset frequency band to determine whether the fundamental frequency of the cable meets the preset frequency band, and calculate the cable force of the cable according to the correlation between the fundamental frequency of the cable and the cable force when the fundamental frequency of the cable meets the preset frequency band.

[0028] The second object of the present invention is achieved by the following technical solutions:

[0029] A method for measuring the cable force of a cable, which is applied to a cable force measuring device adopted by the first object of the present invention, the method for measuring the cable force of the cable includes:

[0030] Data acquisition step: acquiring an original data signal containing cable vibration information;

[0031] Data processing step: amplifying the original data signal according to a preset frequency band and extracting the frequency to obtain frequency information;

[0032] Cable force calculation step: calculating the fundamental frequency of the cable according to the frequency information, and then calculating the cable force of the cable according to the fundamental frequency of the cable and the relationship formula between the fundamental frequency of the cable and the cable force.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] By installing a data acquisition device on the cable of the structure to be measured to acquire an original data signal containing cable vibration information, and designing a signal amplification circuit and a frequency extraction circuit to calculate the fundamental frequency of the cable in a hardware manner, the present invention can greatly improve the calculation accuracy of the fundamental frequency of the cable, thereby improving the calculation accuracy of the cable force and reducing the calculation error of the cable force. Description of the Drawings

[0035] Figure 1 It is a module diagram of a cable force measuring device provided by the present invention;

[0036] Figure 2 It is a schematic diagram of the installation position of the data acquisition device and the cable when the structure to be measured is a bridge provided by the present invention;

[0037] Figure 3 is Figure 1 a circuit schematic diagram of the signal amplification circuit in

[0038] Figure 4 is Figure 3 a signal change schematic diagram processed by the signal amplification circuit in

[0039] Figure 5 is Figure 1 a circuit schematic diagram of the frequency extraction circuit in

[0040] Figure 6 isFigure 5 Schematic diagram of signal variation processed by the frequency extraction circuit in

[0041] Figure 7 Flowchart of a cable force measurement method provided by the present invention.

[0042] In the figure: 1. Cable; 2. Data acquisition device. Specific implementation mode

[0043] Next, in combination with the accompanying drawings and specific implementation modes, the present invention will be further described. It should be noted that, on the premise of no conflict, the following described embodiments or technical features can be arbitrarily combined to form new embodiments.

[0044] Embodiment 1

[0045] The present invention processes the acquired original data signal containing vibration information in a hardware manner and then extracts the frequency to obtain the fundamental frequency of the cable when the cable vibrates, realizing the acquisition of the fundamental frequency of the cable of the structure to be measured at the hardware level. Then, in combination with the relationship between the fundamental frequency of the cable and the cable force, the cable force of the cable of the structure to be measured is calculated.

[0046] More preferably, the present invention provides a preferred embodiment, a cable force measurement device, as Figure 1 shown, including a data acquisition device and a data processing device.

[0047] Among them, the data acquisition device is installed on the cable of the structure to be measured and is used to acquire the original data signal when the cable vibrates. The original data signal refers to the signal containing the vibration information of the cable. Specifically, the data acquisition device is an acceleration sensor or a vibration sensor. By installing the acceleration sensor or the vibration sensor on the cable of the structure to be measured, as Figure 2 shown, if the structure to be measured is a bridge with a cable 1, the data acquisition device 2 is installed on the cable 1.

[0048] When the structure to be measured vibrates, the cable will also vibrate and generate acceleration or vibration. At this time, the acceleration signal or vibration signal when the cable vibrates can be obtained through the acceleration sensor or the vibration sensor, and the original data signal containing the vibration information of the cable can be obtained by collecting the acceleration signal or the vibration signal. Specifically, the cable of the structure to be measured in this embodiment can be the cable of a bridge, the cable of a building, the cable of a ship, etc., which is specifically determined according to the actual measurement requirements.

[0049] Further, the data processing device is electrically connected to the data acquisition device, and is configured to obtain the original data signal collected by the data acquisition device, amplify and perform analog-to-digital conversion on the original data signal, extract the frequency information of the original data signal, and then obtain the fundamental frequency of the cable according to the frequency information of the original data signal. Finally, the cable force is calculated according to the relationship between the fundamental frequency of the cable, the fundamental frequency of the cable and the cable force, so as to realize the measurement of the cable force of the cable of the structure to be measured.

[0050] More specifically, as Figure 1 shown, the data processing device includes a main control chip, a signal amplification circuit, a frequency extraction circuit and an analog-to-digital conversion circuit. Among them, the input end of the signal amplification circuit is electrically connected to the data acquisition device, and the output end is electrically connected to the input end of the frequency extraction circuit. The output end of the frequency extraction circuit is electrically connected to the main control chip through the analog-to-digital conversion circuit.

[0051] The signal amplification circuit is configured to amplify the original data signal. Specifically, in order to avoid the influence of other interference signals, when the original data signal is amplified in this embodiment, the corresponding frequency range is set, and the signal components within the corresponding frequency range in the original data signal are amplified according to the set frequency. At the same time, the signal components of other frequencies can also be attenuated. As Figure 4 shown, the signal component with frequency f = f2 is amplified, and the signal components with frequencies f = f1 and f = f3 are attenuated. That is, the signal amplification circuit in this embodiment is a single-frequency point signal amplification circuit.

[0052] Among them, the set frequency range refers to the frequency range of the data signal used to affect the cable force.

[0053] Preferably, the implementation manner of the signal amplification circuit includes, but is not limited to, a resonant circuit or an active band-pass filter amplification circuit.

[0054] More specifically, as Figure 3 shown, the signal amplification circuit includes a first resistor R1, a second resistor R2, a third resistor R3, a first capacitor C1, a second capacitor C2 and a first operational amplifier D1. Among them, the first end of the first resistor R1 is electrically connected to the data acquisition device, and the second end is electrically connected to the inverting input end of the first operational amplifier D1 through the second capacitor C2. Specifically, the data acquisition device can be expressed as a sensor signal source L.

[0055] One end of the second resistor R2 is grounded, and the other end is connected between the second end of the first resistor R1 and the second capacitor C2. One end of the first capacitor C1 is connected between the second end of the first resistor R1 and the second capacitor C2, and the other end is electrically connected to the output end of the first operational amplifier D1. One end of the third resistor R3 is connected between the second capacitor C2 and the inverting input end of the first operational amplifier D1, and the other end is connected between the first capacitor C1 and the output end of the first operational amplifier D1. The non-inverting input end of the first operational amplifier D1 is grounded, and the output end of the first operational amplifier D1 is also electrically connected to the input end of the frequency extraction circuit.

[0056] By adjusting the magnitudes of the second resistor R2 and the third resistor R3, the frequency of the amplified frequency point signal component can be achieved. For example, by adjusting the resistance values of the second resistor R2 and the third resistor R3, the signal component at the corresponding frequency in the received original data signal is amplified separately, while the signal components at other frequencies are attenuated. Among them, the first resistor R1, the second resistor R2, and the third resistor R3 are all programmable resistors, and C is the capacitance value of the capacitance of the single-frequency point amplification circuit, that is, the sum of the capacitance values of the first capacitor C1 and the second capacitor C2. The present invention dynamically adjusts the resistance values of the second resistor R2 and the third resistor R3 through a program to achieve the function of controlling the amplification frequency point, and sequentially scans the signal components at the corresponding frequency points within the range corresponding to the fundamental frequency of the cable, so as to achieve the hardware frequency scanning effect and obtain the spectral analysis diagram of the vibration signal of the cable. Among them, the spectral analysis diagram is a two-dimensional curve graph of the strength of each frequency component in a vibration signal. By performing frequency scanning to realize the drawing of the spectrogram, the horizontal axis represents the frequency point, and the vertical axis represents the signal strength corresponding to the frequency point. Through this graph, the signal fundamental frequency can be intuitively obtained. The spectral analysis diagram is completely obtained by hardware means, and has the advantages of small error, high precision, and fast speed. Furthermore, the output end of the frequency extraction circuit is electrically connected to the main control chip, and is used for differentiating and dividing the amplified signal and then performing analog-to-digital conversion, and sending the converted digital signal to the main control chip, so that the main control chip obtains the fundamental frequency of the cable according to the digital signal.

[0057] More specifically, as shown in, the frequency extraction circuit includes a first differential circuit, a second differential circuit, an inverting circuit, and a division circuit. Among them, the input end of the first differential circuit is electrically connected to the output end of the signal amplification circuit, and the output end of the first differential circuit is electrically connected to the input end of the second differential circuit. The output end of the second differential circuit is electrically connected to the input end of the inverting circuit. The output end of the inverting circuit is electrically connected to the input end of the division circuit. The output end of the division circuit is electrically connected to the main control chip.

[0058] More specifically, as Figure 5 shown, the frequency extraction circuit includes a first differential circuit, a second differential circuit, an inverting circuit, and a division circuit. Among them, the input end of the first differential circuit is electrically connected to the output end of the signal amplification circuit, and the output end of the first differential circuit is electrically connected to the input end of the second differential circuit. The output end of the second differential circuit is electrically connected to the input end of the inverting circuit. The output end of the inverting circuit is electrically connected to the input end of the division circuit. The output end of the division circuit is electrically connected to the main control chip.

[0059] The first differential circuit is used to perform differential processing on the amplified signal. The second differential circuit is used to perform a second differential processing on the signal after the differential processing.

[0060] The inverting circuit is used to invert the signal after the second differentiation and input it into the division circuit. The division circuit is used to divide the inverted signal by the input signal and output it to the analog-to-digital conversion circuit.

[0061] The analog-to-digital conversion circuit is used to convert the divided signal into a digital signal and send it to the main control chip.

[0062] The main control chip is used to obtain the fundamental frequency of the cable according to the digital signal and calculate the cable force corresponding to the fundamental frequency of the cable by combining the relationship between the fundamental frequency of the cable and the cable force.

[0063] Among them, the relationship between the fundamental frequency of the cable and the cable force is specifically:

[0064] T = 4ml 2 f 2 (1);

[0065] Among them, T is the cable force, m is the linear density of the cable, l is the length between the cable anchoring points, and f is the fundamental frequency of the cable.

[0066] More specifically, as Figure 6 shown, the first differential circuit is used to perform differential processing on the amplified original data signal V in = Asinωt to obtain the differential original data signal Among them, A is the signal amplitude, ω is the signal angular frequency, and t is the time.

[0067] Next, the second differential circuit is used to perform a second differential processing on the original data signal after the first differentiation , and then the signal becomes At this time, the frequency information of the signal has been extracted into the amplitude. Then, after the signal is inverted by the inverting circuit and the inverted signal is divided by the input signal through the division circuit, the output result is and this signal is sent to the analog-to-digital conversion module for analog-to-digital conversion. Obviously, the output signal can be substituted with ω = 2πf into to obtain the voltage of the analog signal as V out = 4π 2 f 2 , so that the voltage of the digital signal after being converted by the analog-to-digital conversion module is V out = 4π 2 f 2 , and then the main control chip can calculate the fundamental frequency of the cable according to the voltage of the signal.

[0068] More specifically, as Figure 5 shown, the first differential circuit includes a third capacitor C3, a fourth resistor R4, a fifth resistor R5, and a second operational amplifier D2.

[0069] The second differential circuit includes a fourth capacitor C4, a sixth resistor R6, a seventh resistor R7, and a third operational amplifier D3.

[0070] The inverting circuit includes a fifth capacitor C5, an eighth resistor R8, a ninth resistor R9, and a fourth operational amplifier D4.

[0071] The division circuit includes a sixth capacitor C6, a tenth resistor R10, an eleventh resistor R11, a fifth operational amplifier D5, and a multiplier N.

[0072] Among them, one end of the third capacitor C3 is electrically connected to the output end of the signal amplification circuit for inputting the amplified signal. The other end of the third capacitor C3 is electrically connected to the inverting input end of the second operational amplifier D2. One end of the fourth resistor is connected between the third capacitor C3 and the inverting input end of the second operational amplifier D2, and the other end is electrically connected to the output end of the second operational amplifier D2. The non-inverting input end of the second operational amplifier D3 is grounded. The output end of the second operational amplifier is electrically connected to the inverting input end of the third operational amplifier D2 through the fourth capacitor C4. One end of the seventh resistor R7 is grounded, and the other end is electrically connected to the non-inverting input end of the third operational amplifier D3. One end of the sixth resistor R6 is connected between the fourth capacitor C4 and the inverting input end of the third operational amplifier D3, and the other end is electrically connected to the output end of the third operational amplifier D3.

[0073] The output end of the third operational amplifier D3 is also electrically connected to the inverting input end of the fourth operational amplifier D4 through the fifth capacitor C5. One end of the ninth resistor R9 is grounded, and the other end is electrically connected to the non-inverting input end of the fourth operational amplifier D4. One end of the eighth resistor R8 is connected between the fifth capacitor C5 and the inverting input end of the fourth operational amplifier D4, and the other end is electrically connected to the output end of the fourth operational amplifier D4.

[0074] The output terminal of the fourth operational amplifier D4 is electrically connected to the inverting input terminal of the fifth operational amplifier D5 through the sixth capacitor C6. One end of the eleventh resistor R11 is grounded, and the other end is electrically connected to the non-inverting input terminal of the fifth operational amplifier D5. One end of the tenth resistor R10 is connected between the sixth capacitor C6 and the inverting input terminal of the fifth operational amplifier D5, and the other end is electrically connected to the first terminal of the multiplier N. The second terminal of the multiplier N is connected between the signal amplifier and the third capacitor C3, and the second terminal is electrically connected to the output terminal of the fifth operational amplifier D5. Among them, the function of the multiplier is to divide the output signal of the fifth operational amplifier D5 by the output signal of the signal amplification circuit to obtain a feedback signal, and the feedback signal acts on the input terminal of the fifth operational amplifier D5 in reverse. Since the multiplier and the fifth operational amplifier form a balanced system, the output signal of the fifth operational amplifier D5 is equivalent to the result of dividing the input signal of the fifth operational amplifier D5 by the output signal of the signal amplification circuit, realizing the division function.

[0075] Preferably, the main control chip is further configured to compare the calculated cable fundamental frequency with a preset frequency band, and when the cable fundamental frequency meets the preset frequency band, calculate the cable tension according to the relationship between the cable fundamental frequency and the cable tension.

[0076] Preferably, to improve the accuracy of single-frequency point measurement and prevent frequency components near the frequency point from interfering with frequency calculation, the main control chip also compares the acquired frequency information with the preset frequency band set by the signal amplification circuit. If the frequency meets the preset frequency band, it indicates that there is a corresponding frequency component in the signal, so as to form a spectrum for subsequent identification of the fundamental frequency. If not, it indicates that the frequency component is of little importance in the signal or the signal at the corresponding frequency point does not exist, and this measurement can be ignored.

[0077] The cable tension measurement method provided by the present invention measures the signal containing vibration information generated when the cable vibrates, then calculates the cable fundamental frequency, and then calculates the cable tension according to the relationship between the cable fundamental frequency and the cable tension, having the advantages of high measurement accuracy, convenient installation, and convenient measurement. At the same time, when the present invention amplifies the signal, it adopts the hardware single-frequency point amplification technology to accurately amplify the single frequency component in the signal without amplifying other frequency components or attenuating other frequency components, achieving the effect of greatly amplifying the signal at the corresponding frequency point.

[0078] Meanwhile, the present invention also realizes frequency extraction from the analog signal layer by adopting a frequency extraction circuit. Different from the conventional software-based frequency extraction method, it can directly obtain signal frequency information at the analog signal level, eliminating the need for analog-to-digital conversion. It adopts operations similar to approximation and quantization in software acquisition, improving the signal-to-noise ratio and measurement accuracy. At the same time, the frequency extraction method provided by the present invention has a wider application range. It can not only be used for the extraction of the fundamental frequency of stay cables, but also be applied to the frequency extraction in various other sensing circuit scenarios. At the same time, the frequency extraction circuits adopted by the present invention are all composed of simple electronic components, having the advantages of simple design and convenient application.

[0079] Embodiment 2

[0080] Based on Embodiment 1, the present invention also provides a method for measuring the stay cable force, which is applied to a stay cable force measuring device as provided by the present invention, as Figure 7 shown. The stay cable force measuring method includes:

[0081] Step S1: Obtain the original data signal containing the vibration information of the stay cable. Specifically, a data acquisition device, such as an acceleration sensor or a vibration sensor, can be installed on the stay cable of the structure to be measured to collect the original data signal containing the vibration information.

[0082] Step S2: Amplify the original data signal according to a preset frequency band and perform frequency extraction to obtain frequency information. Specifically, after amplifying and extracting the frequency of the original data signal, the frequency information of the signal can be obtained. For example, the signal amplification circuit and frequency extraction circuit adopted in Embodiment 1 of the present invention are used to realize the amplification and frequency extraction of the signal.

[0083] Step S3: Calculate the fundamental frequency of the stay cable according to the frequency information, and then calculate the stay cable force according to the relationship between the fundamental frequency of the stay cable and the stay cable force.

[0084] The fundamental frequency of the stay cable can be obtained according to the frequency information of the signal, and then the stay cable force can be calculated by combining the relationship between the fundamental frequency of the stay cable and the stay cable force.

[0085] Preferably, when calculating the fundamental frequency of the stay cable in Step S3, the fundamental frequency of the stay cable is also matched and compared with a preset frequency band. When the fundamental frequency of the stay cable meets the preset frequency band, the stay cable force is calculated. Through this feedback comparison, it can be further verified whether there is a signal related to vibration in the processed signal. If so, the next step of calculation is continued. If not, it means the signal is incorrect, and the data is discarded, and Step S1 is continued to re-obtain the original data signal.

[0086] The cable force measurement method provided by the present invention solves the problems in the prior art such as low cable force measurement accuracy and large errors. At the same time, combined with hardware equipment to realize signal processing, different from the previous software frequency extraction method, it can directly obtain signal frequency information at the analog signal level, eliminating the analog-to-digital conversion, and adopting operations similar to and quantization of software acquisition, improving the signal-to-noise ratio and measurement accuracy. At the same time, the frequency extraction method provided by the present invention has a wider application range, and can be used not only for the extraction of the fundamental frequency of cables, but also for the extraction of frequencies in various other sensing circuit scenarios.

[0087] The above embodiments are only the preferred embodiments of the present invention, and the scope of protection of the present invention cannot be limited thereby. Any non-substantive changes and substitutions made by those skilled in the art based on the present invention belong to the scope of protection required by the present invention.

Claims

1. A cable tension measurement device, characterized in that, The cable force measurement device includes a data acquisition device and a data processing device; wherein, the data acquisition device is installed on the cable of the structure to be measured and is used to acquire the original data signal when the cable vibrates; the data processing device is electrically connected to the data acquisition device and is used to acquire the original data signal, amplify and extract the signal components corresponding to the frequencies in the original data signal according to a preset frequency band to obtain the fundamental frequency of the cable, and finally calculate the cable force according to the fundamental frequency of the cable and the correlation between the fundamental frequency of the cable and the cable force.

2. The cable force measuring device according to claim 1, characterized in that The data acquisition device is an acceleration sensor or a vibration sensor; wherein, when the data acquisition device is an acceleration sensor, it is used to acquire the acceleration signal of the cable and then obtain the original data signal of the cable vibration according to the acceleration signal; when the data acquisition device is a vibration sensor, it is used to acquire the vibration signal of the cable and then obtain the original data signal of the cable vibration according to the vibration signal.

3. The cable force measuring device according to claim 1, characterized in that, The data processing device includes a main control chip, a signal amplification circuit, a frequency extraction circuit and an analog-to-digital conversion module; wherein, the input end of the signal amplification circuit is electrically connected to the data acquisition device, and the output end is electrically connected to the input end of the frequency extraction circuit; the output end of the frequency extraction circuit is electrically connected to the main control chip through the analog-to-digital conversion module; The signal amplification circuit is used to amplify the signal components in the original data signal whose frequencies conform to the preset frequency band according to the preset frequency band, so as to send the amplified original data signal to the frequency extraction circuit; The frequency extraction circuit is used to extract the frequency of the amplified original data signal and send it to the analog-to-digital conversion module, so that the analog-to-digital conversion module converts the original data signal after frequency extraction into a digital signal and sends it to the main control chip; The main control chip is used to obtain the frequency information of the digital signal according to the digital signal, obtain the fundamental frequency of the cable according to the frequency information, and then calculate the cable force according to the fundamental frequency of the cable and the corresponding relationship between the fundamental frequency of the cable and the cable force.

4. The cable force measuring device according to claim 1, characterized in that, The signal amplification circuit includes a resonant circuit or an active band-pass filter amplification circuit.

5. The cable force measuring device according to claim 1, characterized in that, The signal amplification circuit includes a first resistor, a second resistor, a third resistor, a first capacitor, a second capacitor, and a first operational amplifier. The first end of the first resistor is electrically connected to the data acquisition device, and the second end is electrically connected to the inverting input terminal of the first operational amplifier through the second capacitor. The first end of the second resistor is grounded, and the second end is connected between the second end of the first resistor and the second capacitor. The first end of the second capacitor is connected between the first resistor and the second capacitor, and the other end is electrically connected to the output terminal of the first operational amplifier. The first end of the third resistor is connected between the second capacitor and the inverting input terminal of the first operational amplifier, and the other end is connected between the first capacitor and the output terminal of the first operational amplifier. The non-inverting input terminal of the first operational amplifier is grounded. The output terminal of the first operational amplifier is electrically connected to the output terminal of the frequency extraction circuit. The first resistor, the second resistor, and the third resistor are programmable resistors.

6. The cable force measuring device according to claim 1, characterized in that The frequency extraction circuit includes a first differentiating circuit, a second differentiating circuit, an inverting circuit, and a division circuit. Among them, the input terminal of the first differentiating circuit is electrically connected to the output terminal of the signal amplification circuit, and the output terminal of the first differentiating circuit is electrically connected to the input terminal of the second differentiating circuit. The output terminal of the second differentiating circuit is electrically connected to the input terminal of the inverting circuit. The output terminal of the inverting circuit is electrically connected to the first input terminal of the division circuit, and the second input terminal of the division circuit is electrically connected to the output terminal of the signal amplification circuit. The output terminal of the division circuit is electrically connected to the main control chip through the analog-to-digital conversion module. The first differentiating circuit is used to perform differential processing on the amplified original data signal and send it to the second differentiating circuit, so that the second differentiating circuit performs second differential processing on the differentially processed original data signal. The inverting circuit is used to invert the original data signal after the second differential processing and input it into the division circuit, so that the division circuit divides the inverted original data signal by the amplified original data signal and then inputs it into the analog-to-digital conversion module for analog-to-digital conversion. The main control chip is used to obtain the converted digital signal through the analog-to-digital conversion module, obtain the frequency information according to the digital signal, and then calculate the fundamental frequency of the cable according to the frequency information.

7. The cable force measuring device according to claim 6, characterized in that, The first differentiating circuit includes a third capacitor, a fourth resistor, a fifth resistor, and a second operational amplifier. The second differentiating circuit includes a fourth capacitor, a sixth resistor, a seventh resistor, and a third operational amplifier. The inverting circuit includes a fifth capacitor, an eighth resistor, a ninth resistor, and a fourth operational amplifier. The division circuit includes a sixth capacitor, a tenth resistor, an eleventh resistor, a fifth operational amplifier, and a multiplier. One end of the third capacitor is electrically connected to the output end of the signal amplification circuit, and the other end is electrically connected to the inverting input end of the second operational amplifier; one end of the fourth resistor is connected between the third capacitor and the inverting input end of the second operational amplifier, and the other end is electrically connected to the output end of the second operational amplifier; the non-inverting input end of the second operational amplifier is grounded; The output end of the second operational amplifier is electrically connected to the inverting input end of the third operational amplifier through a fourth capacitor; one end of the seventh resistor is grounded, and the other end is electrically connected to the non-inverting input end of the third operational amplifier; one end of the sixth resistor is connected between the fourth capacitor and the inverting input end of the third operational amplifier, and the other end is electrically connected to the output end of the third operational amplifier; The output end of the third operational amplifier is also electrically connected to the inverting input end of the fourth operational amplifier through a fifth capacitor; one end of the ninth resistor is grounded, and the other end is electrically connected to the non-inverting input end of the fourth operational amplifier; One end of the eighth resistor is connected between the fifth capacitor and the inverting input end of the fourth operational amplifier, and the other end is electrically connected to the output end of the fourth operational amplifier; The output end of the fourth operational amplifier is electrically connected to the inverting input end of the fifth operational amplifier through a sixth capacitor; one end of the eleventh resistor is grounded, and the other end is electrically connected to the non-inverting input end of the fifth operational amplifier; One end of the tenth resistor is connected between the sixth capacitor and the inverting input end of the fifth operational amplifier, and the other end is electrically connected to the first end of the multiplier; the second end of the multiplier is connected between the signal amplifier and the third capacitor, and the second end is electrically connected to the output end of the fifth operational amplifier.

8. The cable force measuring device according to claim 1, characterized in that The formula for the corresponding relationship between the fundamental frequency of the cable and the cable force is: T = 4 ml 2 f 2 (1); Where T is the cable force, m is the cable linear density, l is the length between the cable anchoring points, and f is the fundamental frequency of the cable.

9. The cable force measuring device according to claim 1, wherein The main control chip is further configured to match the fundamental frequency of the cable with a preset frequency band to determine whether the fundamental frequency of the cable meets the preset frequency band, and when the fundamental frequency of the cable meets the preset frequency band, calculate the cable force of the cable according to the correlation between the fundamental frequency of the cable and the cable force.

10. A cable force measurement method, applied to a cable force measurement device as described in any one of claims 1-9, characterized in that, The method for measuring the cable force includes: Data acquisition step: acquiring an original data signal containing cable vibration information; Data processing step: amplifying the original data signal according to a preset frequency band and extracting the frequency to obtain frequency information; Cable force calculation step: calculating the fundamental frequency of the cable according to the frequency information, and further calculating the cable force of the cable according to the fundamental frequency of the cable and the relationship formula between the fundamental frequency of the cable and the cable force.

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