CN117647347A - Frequency-method inhaul cable force measurement method based on frequency optimization - Google Patents
Frequency-method inhaul cable force measurement method based on frequency optimization Download PDFInfo
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Abstract
The invention provides a frequency method inhaul cable force measuring method based on frequency optimization, which comprises the following steps: acquiring waveform data of an X axis, a Y axis and a Z axis; obtaining the original waveform of each axis; obtaining delay waveforms of each axis; superposing the delay waveforms of the shafts and the original waveforms of the shafts to obtain waveform data of the shafts after superposition; calculating waveform energy of each axis; obtaining delay time corresponding to the minimum value of the waveform energy of each axis, and obtaining delay time corresponding to the maximum value of the waveform energy of each axis; calculating the frequency of the minimum scene of each axis amplitude, and calculating the frequency of the maximum scene of each axis amplitude; calculating the corresponding frequency mean value of each axis based on the frequency of the minimum amplitude scene of each axis and the frequency of the maximum amplitude scene of each axis; calculating the vibration frequency of the inhaul cable based on the frequency average value of each shaft; and calculating the cable force of the stay cable. The invention effectively shields the interference of vibration noise, ensures the acquisition of effective and accurate vibration frequency and improves the accuracy of cable force measurement of the inhaul cable.
Description
Technical Field
The invention relates to a data processing method in the field of cable force measurement, in particular to a frequency method cable force measurement method based on frequency optimization.
Background
In modern curtain wall structures, the cable is used as an important stress member, and accurate measurement of the cable force plays a vital role in ensuring the stability and safety of the curtain wall structure. At present, a frequency method is commonly adopted in engineering application to measure the cable force of a curtain wall inhaul cable. The method for measuring the cable force of the curtain wall by using the frequency method is to determine the cable force by testing the vibration frequency of the cable of the curtain wall and utilizing the inherent relation between the vibration frequency and the cable force of the cable. The method is suitable for measuring the cable force of various types of cables under various working conditions, and is suitable for both cables with larger cross-sectional areas and cables with existing structures. The application range is wide, the testing method is simple and convenient, and the repeated use is convenient.
However, the field measurement environment is complex, and various interference factors are more. The vibration signal is disturbed by the vibration sensor's position and fixing mode, the position and size of the applied excitation, the earth's self-vibration, the building's self-vibration, the surrounding vehicles and personnel's activity, and other environmental vibration factors during the measurement. It is difficult to obtain stable and accurate vibration frequency by using the traditional frequency method, which directly influences the accuracy of the measurement of the cable force of the inhaul cable. It is therefore a challenge to obtain a high accuracy vibration frequency.
Disclosure of Invention
Aiming at the defects existing in the prior art, the invention provides a frequency method inhaul cable force measuring method based on frequency optimization, which reduces the interference of a measuring environment on vibration signals by optimizing the vibration signals through a comb filtering algorithm, extracts high-precision vibration frequency and calculates the cable force of an inhaul cable according to the vibration frequency.
The comb filtering algorithm optimizes the vibration signal according to the following principle:
the vibration waveform is formed by superposing a plurality of sine waves with different frequencies. According to sine wave phase knowledge, a sine wave with a certain frequency is overlapped with a waveform delayed by a plurality of milliseconds, if the phases are identical, the sine wave amplitude is twice at the maximum, and if the phases are opposite, the sine wave amplitude is zero at the minimum.
In the cable force measurement of the cable, a vibration signal generated by applying excitation to the cable is transmitted along the cable to form an original vibration waveform;
processing the original vibration waveform to obtain an original waveform;
delaying the original waveform to obtain a delayed waveform;
the original waveform and the delay waveform are overlapped, and if the phases of the overlapped waveforms are identical, the amplitude is maximum and the energy is maximum at the moment; if the phases are exactly opposite, the amplitude is at a minimum and the energy is at a minimum.
Wherein,
(1) Amplitude minimum scene:
at this time, the energy of the superimposed waveform is reduced to the lowest, the phase of the delayed waveform is exactly opposite to that of the original waveform, and the delay time is equal to the odd multiple of 1/2 period corresponding to the original waveform;
the conversion formula is as follows:
T＝1/f；
N/1000＝k×T/2＝k/2f；
converting N/1000 to standard unit seconds;
T＝(N×2)/(1000×k)，f＝(1000×k)/(N×2)；
wherein,
n is delay time, unit millisecond, f is frequency, k/2 is frequency order, and T is period.
(2) Amplitude maximum scene:
at this time, the energy of the superimposed waveform rises to the highest, the phase of the delayed waveform is exactly equal to the phase of the original waveform, and the delay time is equal to the integral multiple of the corresponding period of the original waveform;
the conversion formula is as follows:
T＝1/f；
N/1000＝k×T＝k/f；
converting N/1000 to standard unit seconds;
T＝N/(1000×k)，f＝(1000×k)/N；
wherein,
n is delay time, unit millisecond, f is frequency, k is frequency order, and T is period.
Based on the principle, the invention provides a frequency method inhaul cable force measuring method based on frequency optimization, which comprises the following steps:
acquiring waveform data of an X axis, a Y axis and a Z axis;
preferably, for each cable, a vibration sensor is fixed, the vibration sensor adopting a triaxial accelerometer;
applying excitation, namely applying excitation to each inhaul cable on site, and transmitting vibration signals generated by excitation along the inhaul cable to form an original vibration waveform;
acquiring waveform data of each axis, and acquiring waveform data of an X axis, a Y axis and a Z axis by a vibration sensor aiming at each inhaul cable;
and uploading the waveform data of each axis to the cloud platform in real time by the vibration sensor.
Acquiring original waveforms of all axes based on the waveform data of all axes;
preferably, the raw waveform for each axis is obtained by subtracting the mean value from the waveform data for each axis.
Obtaining each axis delay waveform based on the original waveform of each axis;
preferably, each axis of the delay waveform is obtained by delaying each axis of the original waveform, including:
initializing delay time, setting delay time intervals, keeping the waveform data length unchanged, and obtaining delay waveforms of each delay time interval of each axis.
Superposing the delay waveforms of the shafts and the original waveforms of the shafts to obtain waveform data of the shafts after superposition;
preferably, the superimposed waveform data for each axis is obtained by adding the delay waveform data for each axis to the original waveform data for each axis.
Calculating waveform energy of each axis based on the superimposed waveform data of each axis;
preferably, the waveform energy calculation method for each axis is as follows:
calculating the square sum of the waveform data after superposition of each axis;
or the square root of the sum of squares of the superimposed waveform data for each axis.
Based on the waveform energy of each axis, obtaining delay time corresponding to the waveform energy of each axis falling to the minimum value, and obtaining delay time corresponding to the waveform energy of each axis rising to the maximum value;
calculating the frequency of the minimum scene of the amplitude of each axis based on the delay time corresponding to the waveform energy of each axis falling to the minimum value;
preferably, the frequency calculation formula of the amplitude minimum scene of each axis is:
f＝(1000×k)/(N×2)；
wherein f is frequency, k/2 is frequency order, and N is delay time;
calculating the frequency of the maximum scene of the amplitude of each axis based on the delay time corresponding to the maximum value of the waveform energy of each axis;
preferably, the frequency calculation formula of the maximum amplitude scene of each axis is as follows:
f＝(1000×k)/N；
where f is the frequency, k is the frequency order, and N is the delay time.
And calculating the corresponding frequency mean value of each axis based on the frequency of the minimum amplitude scene of each axis and the frequency of the maximum amplitude scene of each axis.
Calculating the vibration frequency of the inhaul cable based on the frequency average value of each shaft;
preferably, the cable vibration frequency is obtained by:
selecting a frequency mean value closest to the Z-axis frequency mean value from the X-axis frequency mean value and the Y-axis frequency mean value;
calculating the average value of the nearest frequency average value and the Z-axis frequency average value;
or calculating the average value of the frequency average value of each axis.
Calculating a cable force based on the cable vibration frequency;
preferably, the calculation formula of the inhaul cable force is as follows:
T＝4×p×f k 2 ×L 2 /k 2 –EI×π 2 ×k 2 /L 2 ；
wherein p is the cable meter weight, L is the cable length, EI is the cable bending stiffness, k is the vibration frequency order, f k Is the k-order vibration frequency.
Compared with the prior art, the invention has the beneficial effects that:
the original vibration waveform is processed through the comb filtering algorithm, so that the interference of environmental vibration noise from earth self-vibration, building self-vibration, surrounding vehicles, personnel activities and the like is effectively shielded, the effective and accurate vibration frequency can be obtained in any complex environment, and the accuracy of cable force measurement of the inhaul cable is improved.
Drawings
FIG. 1 is a flow chart of a frequency method inhaul cable force measurement method based on frequency optimization disclosed by the invention;
FIG. 2 is a flow chart of obtaining a vibration frequency of a cable according to an embodiment of the present invention;
FIG. 3 is a diagram showing the original waveform of the Z-axis fundamental frequency of the north-15 cable disclosed in one embodiment of the invention;
FIG. 4 is a superimposed waveform of a north-15 cable Z-axis fundamental delay 254ms according to one embodiment of the present invention;
FIG. 5 is a superimposed waveform diagram of a north-15 cable Z-axis fundamental delay 507ms in accordance with one embodiment of the present invention;
FIG. 6 is a flow chart of obtaining a vibration frequency of a cable in accordance with an embodiment of the present invention;
FIG. 7 is a flow chart of obtaining a vibration frequency of a cable in accordance with an embodiment of the present invention;
FIG. 8 is a flow chart of obtaining a vibration frequency of a cable in accordance with an embodiment of the present invention.
Detailed Description
In order to make the purposes, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described with reference to the accompanying drawings. It is obvious that the described embodiments are some, but not all embodiments of the present invention, wherein the frequency optimization-based method for measuring cable force of a frequency method described in the present invention includes the fundamental frequency optimization described in the fundamental frequency optimization, the second-order frequency optimization, the third-order frequency optimization … … embodiments, and the steps S1 and S2 … … in the embodiments do not limit the unique frequency optimization of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the following, cable force measurement of curtain wall glass cable of a building in Jiangsu province is taken as an example, and for convenience of description, cable force measurement with optimized fundamental frequency of north-15 cable of a building in Jiangsu province is taken as an example.
Example 1
The invention is described in further detail with reference to fig. 1 and 2, and the steps are as follows:
s1: for each inhaul cable, a vibration sensor is fixed, the vibration sensor adopts a triaxial accelerometer, and is 2 meters away from the ground, and the vibration sensor is fixed by adopting a disposable rolling belt and is connected with a power supply.
S2: applying excitation, namely applying manual excitation to each inhaul cable by using a rubber hammer on site, so that the inhaul cable can vibrate freely for 5 minutes, uniformly exerting force as much as possible in the process of applying the inhaul cable excitation, enabling the knocking position to be 1.5 meters away from the ground, and enabling the knocking direction to be perpendicular to the direction of the inhaul cable of the curtain wall.
S3: and acquiring waveform data of each axis, wherein the vibration sensor acquires waveform data of the X axis, the Y axis and the Z axis at a sampling frequency of 1KHZ for each inhaul cable, and each sampling value corresponds to 1 millisecond.
S4: the vibration sensor uploads waveform data of each axis to the cloud platform in real time, the uploading is performed once per second, and the waveform data of 300 seconds are stored in each measurement.
S5: subtracting the average value from the waveform data of each axis to obtain the original waveform of each axis;
the original waveform is shown in the original waveform diagram of the Z-axis fundamental frequency of the north-15 inhaul cable in fig. 3.
S6: for each axis of the original waveform, the initialization delay time n=1 millisecond.
S7: each axis waveform is delayed for N milliseconds, namely N0 are added before the waveform data, N data are deleted, the length of the waveform data is kept unchanged, and each axis delay waveform is obtained.
S8: correspondingly adding the delay waveform data of each axis and the original waveform data of each axis to obtain waveform data after superposition of each axis;
the superimposed waveform data is shown in a superimposed waveform diagram of 254ms for the north-15 cable Z-axis fundamental frequency and a superimposed waveform diagram of 507ms for the north-15 cable Z-axis fundamental frequency in FIG. 4.
S9: and calculating the square sum of waveform data after superposition of each axis to obtain waveform energy of each axis.
S10: let n=n+1, compare N with the waveform length, jump to S7 to execute the loop when N < the waveform length until N is not less than the waveform length.
S11: delay time corresponding to the minimum value of the waveform energy of each axis is recorded, and delay time corresponding to the maximum value of the waveform energy of each axis is recorded.
S12: calculating the frequency of each axis amplitude minimum scene and the frequency of each axis amplitude maximum scene, comprising:
the frequency calculation formula of the minimum amplitude scene of each axis is as follows:
f＝(1000×k)/(N×2)；
wherein f is frequency, k/2 is frequency order, and N is delay time;
the frequency calculation formula of the maximum amplitude scene of each axis is as follows:
f＝(1000×k)/N；
where f is the frequency, k is the frequency order, and N is the delay time.
Taking the north-15 inhaul cable Z-axis fundamental frequency as an example, when the delay is 254 milliseconds, the Z-axis waveform energy first drops to the minimum value, the Z-axis amplitude is the minimum scene, and the fundamental frequency f is the fundamental frequency 1 ＝(1000×1)/(254×2)＝1.9685Hz
The Z-axis waveform energy first rises to a maximum value when delayed by 507 milliseconds, the Z-axis amplitude being the maximum scene, at which the fundamental frequency f 2 ＝(1000×1)/507＝1.9724Hz。
S13: calculating the corresponding frequency mean value of each axis based on the frequency of the minimum scene of each axis amplitude and the frequency of the maximum scene of each axis amplitude;
taking north-15 inhaul cable Z-axis fundamental frequency as an example, the mean value f of the Z-axis fundamental frequency z ＝(f 1 +f 2 )/2。
S14: calculating a cable vibration frequency, comprising:
selecting a frequency mean value closest to the Z-axis frequency mean value from the X-axis frequency mean value and the Y-axis frequency mean value;
calculating the average value of the nearest frequency average value and the Z-axis frequency average value;
taking north-15 inhaul cable as an example, from the fundamental frequency mean value f of X axis x And Y-axis fundamental frequency mean f y Is selected from the mean value f of the fundamental frequency of the Z axis z The nearest fundamental frequency mean;
when f x And f z When the two vibration frequencies are relatively close, the vibration frequency f= (f) of the inhaul cable is calculated x +f z )/2；
When f y And f z When the two vibration frequencies are relatively close, the vibration frequency f= (f) of the inhaul cable is calculated y +f z )/2；
According to the steps, the vibration frequency data of each curtain wall glass stay rope of a building in Jiangsu province is obtained:
s15: the cable force is calculated, and the cable force calculation formula is as follows:
T＝4×p×f k 2 ×L 2 /k 2 –EI×π 2 ×k 2 /L 2
wherein,
p is the weight of inhaul cable per meter, and the unit is kg/m;
l is the length of the inhaul cable and is in unit of m;
EI is cable bending rigidity;
k is the order of the vibration frequency;
f k the frequency of vibration is k-order, in Hz.
Example 2
The invention is described in further detail with reference to fig. 1 and 6, and the steps are as follows:
s1: for each inhaul cable, a vibration sensor is fixed, the vibration sensor adopts a triaxial accelerometer, and is 2 meters away from the ground, and the vibration sensor is fixed by adopting a disposable rolling belt and is connected with a power supply.
S2: applying excitation, namely applying manual excitation to each inhaul cable by using a rubber hammer on site, so that the inhaul cable can vibrate freely for 5 minutes, uniformly exerting force as much as possible in the process of applying the inhaul cable excitation, enabling the knocking position to be 1.5 meters away from the ground, and enabling the knocking direction to be perpendicular to the direction of the inhaul cable of the curtain wall.
S3: and acquiring waveform data of each axis, wherein the vibration sensor acquires waveform data of the X axis, the Y axis and the Z axis at a sampling frequency of 1KHZ for each inhaul cable, and each sampling value corresponds to 1 millisecond.
S4: the vibration sensor uploads waveform data of each axis to the cloud platform in real time, the uploading is performed once per second, and the waveform data of 300 seconds are stored in each measurement.
S5: subtracting the average value from the waveform data of each axis to obtain the original waveform of each axis;
the original waveform is shown in the original waveform diagram of the Z-axis fundamental frequency of the north-15 inhaul cable in fig. 3.
S6: for each axis of the original waveform, the initialization delay time n=1 millisecond.
S7: each axis waveform is delayed for N milliseconds, namely N0 are added before the waveform data, N data are deleted, the length of the waveform data is kept unchanged, and each axis delay waveform is obtained.
S8: correspondingly adding the delay waveform data of each axis and the original waveform data of each axis to obtain waveform data after superposition of each axis;
the superimposed waveform data is shown in a superimposed waveform diagram of 254ms for the north-15 cable Z-axis fundamental frequency and a superimposed waveform diagram of 507ms for the north-15 cable Z-axis fundamental frequency in FIG. 4.
S9: and calculating the square root of the sum of squares of waveform data after superposition of each axis to obtain waveform energy of each axis.
S10: let n=n+1, compare N with the waveform length, jump to S7 to execute the loop when N < the waveform length until N is not less than the waveform length.
S11: delay time corresponding to the minimum value of the waveform energy of each axis is recorded, and delay time corresponding to the maximum value of the waveform energy of each axis is recorded.
S12: calculating the frequency of each axis amplitude minimum scene and the frequency of each axis amplitude maximum scene, comprising:
the frequency calculation formula of the minimum amplitude scene of each axis is as follows:
f＝(1000×k)/(N×2)；
wherein f is frequency, k/2 is frequency order, and N is delay time;
the frequency calculation formula of the maximum amplitude scene of each axis is as follows:
f＝(1000×k)/N；
where f is the frequency, k is the frequency order, and N is the delay time.
Taking the north-15 inhaul cable Z-axis fundamental frequency as an example, when the delay is 254 milliseconds, the Z-axis waveform energy first drops to the minimum value, the Z-axis amplitude is the minimum scene, and the fundamental frequency f is the fundamental frequency 1 ＝(1000×1)/(254×2)＝1.9685Hz
The Z-axis waveform energy first rises to a maximum value when delayed by 507 milliseconds, the Z-axis amplitude being the maximum scene, at which the fundamental frequency f 2 ＝(1000×1)/507＝1.9724Hz。
S13: calculating the corresponding frequency mean value of each axis based on the frequency of the minimum scene of each axis amplitude and the frequency of the maximum scene of each axis amplitude;
taking north-15 inhaul cable Z-axis fundamental frequency as an example, the mean value f of the Z-axis fundamental frequency z ＝(f 1 +f 2 )/2。
S14: calculating a cable vibration frequency, comprising:
selecting a frequency mean value closest to the Z-axis frequency mean value from the X-axis frequency mean value and the Y-axis frequency mean value;
calculating the average value of the nearest frequency average value and the Z-axis frequency average value;
taking north-15 inhaul cable as an example, from the fundamental frequency mean value f of X axis x And Y-axis fundamental frequency mean f y Is selected from the mean value f of the fundamental frequency of the Z axis z The nearest fundamental frequency mean;
when f x And f z When the two vibration frequencies are relatively close, the vibration frequency f= (f) of the inhaul cable is calculated x +f z )/2；
When f y And f z When the two vibration frequencies are relatively close, the vibration frequency f= (f) of the inhaul cable is calculated y +f z )/2。
S15: the cable force is calculated, and the cable force calculation formula is as follows:
T＝4×p×f k 2 ×L 2 /k 2 –EI×π 2 ×k 2 /L 2
wherein,
p is the weight of inhaul cable per meter, and the unit is kg/m;
l is the length of the inhaul cable and is in unit of m;
EI is cable bending rigidity;
k is the order of the vibration frequency;
f k the frequency of vibration is k-order, in Hz.
Example 3
The invention is described in further detail with reference to fig. 1 and 7, and the steps are as follows:
s1: for each inhaul cable, a vibration sensor is fixed, the vibration sensor adopts a triaxial accelerometer, and is 2 meters away from the ground, and the vibration sensor is fixed by adopting a disposable rolling belt and is connected with a power supply.
S2: applying excitation, namely applying manual excitation to each inhaul cable by using a rubber hammer on site, so that the inhaul cable can vibrate freely for 5 minutes, uniformly exerting force as much as possible in the process of applying the inhaul cable excitation, enabling the knocking position to be 1.5 meters away from the ground, and enabling the knocking direction to be perpendicular to the direction of the inhaul cable of the curtain wall.
S3: and acquiring waveform data of each axis, wherein the vibration sensor acquires waveform data of the X axis, the Y axis and the Z axis at a sampling frequency of 1KHZ for each inhaul cable, and each sampling value corresponds to 1 millisecond.
S4: the vibration sensor uploads waveform data of each axis to the cloud platform in real time, the uploading is performed once per second, and the waveform data of 300 seconds are stored in each measurement.
S5: subtracting the average value from the waveform data of each axis to obtain the original waveform of each axis;
the original waveform is shown in the original waveform diagram of the Z-axis fundamental frequency of the north-15 inhaul cable in fig. 3.
S6: for each axis of the original waveform, the initialization delay time n=1 millisecond.
S7: each axis waveform is delayed for N milliseconds, namely N0 are added before the waveform data, N data are deleted, the length of the waveform data is kept unchanged, and each axis delay waveform is obtained.
S8: correspondingly adding the delay waveform data of each axis and the original waveform data of each axis to obtain waveform data after superposition of each axis;
the superimposed waveform data is shown in a superimposed waveform diagram of 254ms for the north-15 cable Z-axis fundamental frequency and a superimposed waveform diagram of 507ms for the north-15 cable Z-axis fundamental frequency in FIG. 4.
S9: and calculating the square sum of waveform data after superposition of each axis to obtain waveform energy of each axis.
S10: let n=n+1, compare N with the waveform length, jump to S7 to execute the loop when N < the waveform length until N is not less than the waveform length.
S11: delay time corresponding to the minimum value of the waveform energy of each axis is recorded, and delay time corresponding to the maximum value of the waveform energy of each axis is recorded.
S12: calculating the frequency of each axis amplitude minimum scene and the frequency of each axis amplitude maximum scene, comprising:
the frequency calculation formula of the minimum amplitude scene of each axis is as follows:
f＝(1000×k)/(N×2)；
wherein f is frequency, k/2 is frequency order, and N is delay time;
the frequency calculation formula of the maximum amplitude scene of each axis is as follows:
f＝(1000×k)/N；
where f is the frequency, k is the frequency order, and N is the delay time.
Taking the north-15 inhaul cable Z-axis fundamental frequency as an example, when the delay is 254 milliseconds, the Z-axis waveform energy first drops to the minimum value, the Z-axis amplitude is the minimum scene, and the fundamental frequency f is the fundamental frequency 1 ＝(1000×1)/(254×2)＝1.9685Hz
The Z-axis waveform energy first rises to a maximum value when delayed by 507 milliseconds, the Z-axis amplitude being the maximum scene, at which the fundamental frequency f 2 ＝(1000×1)/507＝1.9724Hz。
S13: calculating the corresponding frequency mean value of each axis based on the frequency of the minimum scene of each axis amplitude and the frequency of the maximum scene of each axis amplitude;
taking north-15 inhaul cable Z-axis fundamental frequency as an example, the mean value f of the Z-axis fundamental frequency z ＝(f 1 +f 2 )/2。
S14: calculating a cable vibration frequency, comprising:
calculating the average value of the frequency average value of each axis;
taking a north-15 inhaul cable as an example, calculating an X-axis fundamental frequency mean value f x And Y-axis fundamental frequency mean f y And the mean value f of the fundamental frequency of the Z axis z Mean f= (f) x +f y +f z )/3。
S15: the cable force is calculated, and the cable force calculation formula is as follows:
T＝4×p×f k 2 ×L 2 /k 2 –EI×π 2 ×k 2 /L 2
wherein,
p is the weight of inhaul cable per meter, and the unit is kg/m;
l is the length of the inhaul cable and is in unit of m;
EI is cable bending rigidity;
k is the order of the vibration frequency;
f k the frequency of vibration is k-order, in Hz.
Example 4
The invention is described in further detail with reference to fig. 1 and 8, and the steps are as follows:
s1: for each inhaul cable, a vibration sensor is fixed, the vibration sensor adopts a triaxial accelerometer, and is 2 meters away from the ground, and the vibration sensor is fixed by adopting a disposable rolling belt and is connected with a power supply.
S2: applying excitation, namely applying manual excitation to each inhaul cable by using a rubber hammer on site, so that the inhaul cable can vibrate freely for 5 minutes, uniformly exerting force as much as possible in the process of applying the inhaul cable excitation, enabling the knocking position to be 1.5 meters away from the ground, and enabling the knocking direction to be perpendicular to the direction of the inhaul cable of the curtain wall.
S3: and acquiring waveform data of each axis, wherein the vibration sensor acquires waveform data of the X axis, the Y axis and the Z axis at a sampling frequency of 1KHZ for each inhaul cable, and each sampling value corresponds to 1 millisecond.
S4: the vibration sensor uploads waveform data of each axis to the cloud platform in real time, the uploading is performed once per second, and the waveform data of 300 seconds are stored in each measurement.
S5: subtracting the average value from the waveform data of each axis to obtain the original waveform of each axis;
the original waveform is shown in the original waveform diagram of the Z-axis fundamental frequency of the north-15 inhaul cable in fig. 3.
S6: for each axis of the original waveform, the initialization delay time n=1 millisecond.
S7: each axis waveform is delayed for N milliseconds, namely N0 are added before the waveform data, N data are deleted, the length of the waveform data is kept unchanged, and each axis delay waveform is obtained.
S8: correspondingly adding the delay waveform data of each axis and the original waveform data of each axis to obtain waveform data after superposition of each axis;
the superimposed waveform data is shown in a superimposed waveform diagram of 254ms for the north-15 cable Z-axis fundamental frequency and a superimposed waveform diagram of 507ms for the north-15 cable Z-axis fundamental frequency in FIG. 4.
S9: and calculating the square root of the sum of squares of waveform data after superposition of each axis to obtain waveform energy of each axis.
S10: let n=n+1, compare N with the waveform length, jump to S7 to execute the loop when N < the waveform length until N is not less than the waveform length.
S11: delay time corresponding to the minimum value of the waveform energy of each axis is recorded, and delay time corresponding to the maximum value of the waveform energy of each axis is recorded.
S12: calculating the frequency of each axis amplitude minimum scene and the frequency of each axis amplitude maximum scene, comprising:
the frequency calculation formula of the minimum amplitude scene of each axis is as follows:
f＝(1000×k)/(N×2)；
wherein f is frequency, k/2 is frequency order, and N is delay time;
the frequency calculation formula of the maximum amplitude scene of each axis is as follows:
f＝(1000×k)/N；
where f is the frequency, k is the frequency order, and N is the delay time.
Taking the north-15 inhaul cable Z-axis fundamental frequency as an example, when the delay is 254 milliseconds, the Z-axis waveform energy first drops to the minimum value, the Z-axis amplitude is the minimum scene, and the fundamental frequency f is the fundamental frequency 1 ＝(1000×1)/(254×2)＝1.9685Hz
The Z-axis waveform energy first rises to a maximum value when delayed by 507 milliseconds, the Z-axis amplitude being the maximum scene, at which the fundamental frequency f 2 ＝(1000×1)/507＝1.9724Hz。
S13: calculating the corresponding frequency mean value of each axis based on the frequency of the minimum scene of each axis amplitude and the frequency of the maximum scene of each axis amplitude;
taking north-15 inhaul cable Z-axis fundamental frequency as an example, the mean value f of the Z-axis fundamental frequency z ＝(f 1 +f 2 )/2。
S14: calculating a cable vibration frequency, comprising:
calculating the average value of the frequency average value of each axis;
taking a north-15 inhaul cable as an example, calculating an X-axis fundamental frequency mean value f x And Y-axis fundamental frequency mean f y And the mean value f of the fundamental frequency of the Z axis z Mean f= (f) x +f y +f z )/3。
S15: the cable force is calculated, and the cable force calculation formula is as follows:
T＝4×p×f k 2 ×L 2 /k 2 –EI×π 2 ×k 2 /L 2
wherein,
p is the weight of inhaul cable per meter, and the unit is kg/m;
l is the length of the inhaul cable and is in unit of m;
EI is cable bending rigidity;
k is the order of the vibration frequency;
f k the frequency of vibration is k-order, in Hz.
The vibration frequency data obtained after the comb filtering algorithm analysis is used for calculating the cable force value of the curtain wall glass cable of a building in Jiangsu province, the actual test effect is superior, the bending stiffness is considered, the cable force error calculated by a frequency method based on frequency optimization is mostly within 5% and the cable force error of only one cable exceeds 5% and is 7.23%.
The frequency method inhaul cable force measuring method based on frequency optimization effectively shields vibration interference generated by factors such as earth self-vibration, building self-vibration, surrounding vehicles, personnel activities and the like, and ensures that accurate vibration frequency can be effectively obtained in any complex environment.
Claims (10)
1. The frequency method inhaul cable force measuring method based on frequency optimization is characterized by comprising the following steps of:
acquiring waveform data of an X axis, a Y axis and a Z axis;
acquiring original waveforms of all axes based on the waveform data of all axes;
obtaining each axis delay waveform based on the original waveform of each axis;
superposing the delay waveforms of the shafts and the original waveforms of the shafts to obtain waveform data of the shafts after superposition;
calculating waveform energy of each axis based on the superimposed waveform data of each axis;
based on the waveform energy of each axis, obtaining delay time corresponding to the waveform energy of each axis falling to the minimum value, and obtaining delay time corresponding to the waveform energy of each axis rising to the maximum value;
calculating the frequency of the minimum scene of the amplitude of each axis based on the delay time corresponding to the waveform energy of each axis falling to the minimum value; calculating the frequency of the maximum scene of the amplitude of each axis based on the delay time corresponding to the maximum value of the waveform energy of each axis;
calculating the corresponding frequency mean value of each axis based on the frequency of the minimum amplitude scene of each axis and the frequency of the maximum amplitude scene of each axis;
calculating the vibration frequency of the inhaul cable based on the frequency average value of each shaft;
and calculating the cable force based on the cable vibration frequency.
2. The frequency-optimized cable force measurement method according to claim 1, wherein the acquiring the waveform data of the X-axis, the Y-axis and the Z-axis comprises:
a vibration sensor is fixed, and a triaxial accelerometer is adopted for the vibration sensor;
applying an excitation;
collecting waveform data of each axis;
uploading the waveform data of each axis to a cloud platform.
3. A frequency optimized based method for measuring cable tension in a cable according to claim 1, wherein each axis of the original waveform is obtained by subtracting an average value from the waveform data of each axis;
each axis the delay waveform is obtained by delaying each axis the original waveform, including:
initializing delay time, setting delay time intervals, keeping the waveform data length unchanged, and obtaining delay waveforms of each delay time interval of each axis.
4. The frequency-optimized cable force measurement method according to claim 1, wherein the superimposed waveform data of each axis is obtained by adding the delay waveform data of each axis to the original waveform data of each axis.
5. The frequency-optimized cable force measurement method according to claim 1, wherein the waveform energy calculation mode of each shaft is as follows:
and calculating the square sum of the waveform data after superposition of each axis.
6. The frequency-optimized cable force measurement method according to claim 1, wherein the waveform energy calculation mode of each shaft is as follows:
the square root of the sum of squares of the superimposed waveform data for each axis is calculated.
7. The frequency optimization-based frequency method cable force measurement method according to claim 1, wherein the frequency calculation formula of the minimum amplitude scene of each axis is:
f＝(1000×k)/(N×2)；
wherein f is frequency, k/2 is frequency order, and N is delay time;
the frequency calculation formula of the maximum amplitude scene of each axis is as follows:
f＝(1000×k)/N；
where f is the frequency, k is the frequency order, and N is the delay time.
8. The frequency optimization-based method for measuring cable force of a frequency method according to claim 1, wherein the cable vibration frequency is obtained by:
selecting a frequency mean value closest to the Z-axis frequency mean value from the X-axis frequency mean value and the Y-axis frequency mean value;
and calculating the average value of the nearest frequency average value and the Z-axis frequency average value.
9. The frequency optimization-based method for measuring cable force of a frequency method according to claim 1, wherein the cable vibration frequency is obtained by:
and calculating the average value of the frequency average value of each axis.
10. The frequency optimization-based cable force measurement method according to claim 1, wherein the cable force calculation formula is:
T＝4×p×f k 2 ×L 2 /k 2 –EI×π 2 ×k 2 /L 2 ；
wherein p is the cable meter weight, L is the cable length, EI is the cable bending stiffness, k is the vibration frequency order, f k Is the k-order vibration frequency.
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