A method and system for monitoring the tension of stranded wires in a stranding machine

Abstract

The present invention relates to the field of data processing technology, and proposes a wire tension monitoring method and system for a wire stranding machine, including: obtaining a wire tension sequence; decomposing the wire tension sequence into a plurality of component sequences; obtaining a frequency index according to the component sequence; obtaining the possible degree of main tension according to the frequency index, the component sequence and the wire tension sequence; obtaining the main tension sequence according to the possible degree of main tension; obtaining a real-time frequency sequence; obtaining a reference frequency according to the amplitude corresponding to the main tension sequence and other component sequences at the same frequency value; obtaining the degree of tension change according to the number of reference frequencies, the main tension sequence and its real-time frequency sequence; obtaining tension anomaly according to the main tension sequence and the degree of tension change; obtaining the wire tension monitoring result of the wire stranding machine according to the tension anomaly. The present invention performs abnormal monitoring of wire tension through tension anomaly, thereby improving the accuracy of the monitoring result.

Description

Technical Field

[0001] The present invention relates to the technical field of data processing, and in particular to a wire stranding tension monitoring method and system for a wire stranding machine. Background Art

[0002] Wire stranding machines are widely used in the production of cables, ropes, metal wires, etc., and their performance directly affects production efficiency and product quality. In the wire stranding process, wire stranding tension is a key parameter. Too high or too low tension will lead to damage to the wire, deterioration in the quality of the finished product, and reduced production efficiency. Therefore, accurate monitoring and control of wire stranding tension is of great significance for improving the stability of the production process, ensuring product quality, and reducing production costs. Existing monitoring methods, such as piezoelectric sensors and strain gauges, can achieve high-precision tension monitoring. Among them, strain gauges are a commonly used electronic sensor. The monitoring principle is that when the strands are subjected to tension, the strain gauges connected to the wire stranding machine will undergo a slight deformation, and this deformation will cause its resistance to change.

[0003] The strain gauge is connected to other resistors through a Wheatstone bridge circuit, and the change in resistance is measured to calculate the tension. However, the vibration of the equipment or the impact caused during operation will interfere with the signal of the strain gauge. If the frequency of the equipment environment noise of the stranding machine is close to the resonance frequency of the sensor, the measured value may fluctuate, resulting in inaccurate monitoring of the stranded wire tension. Summary of the invention

[0004] The present invention provides a method and system for monitoring the tension of a stranding wire for a stranding machine, so as to solve the problem that the environmental noise of the existing equipment reduces the accuracy of the measurement of the tension of the stranding wire. The technical scheme adopted is as follows:

[0005] The present invention proposes a wire stranding tension monitoring method for a wire stranding machine, the method comprising the following steps:

[0006] Obtaining a strand tension sequence; wherein the strand tension sequence includes a strand tension value at each moment; decomposing the strand tension sequence into a plurality of component sequences;

[0007] The frequency index of the component sequence is obtained according to the order in which the component sequence is obtained; the possible degree of the main tension of the component sequence is obtained according to the frequency index of the component sequence, the similarity between the component sequence and the strand tension sequence, and the disorder of the component sequence; the main tension sequence is obtained by screening according to the possible degree of the main tension of the component sequence;

[0008] Acquire a real-time frequency sequence of a component sequence; the real-time frequency sequence includes the amplitude of the component sequence corresponding to each frequency value; obtain several reference frequencies of the main tension sequence according to the amplitudes corresponding to the main tension sequence and other component sequences at the same frequency value; obtain the tension change degree according to the number of reference frequencies, the local fluctuation of the main tension sequence and the distribution of the real-time frequency sequence of the main tension sequence at the reference frequency;

[0009] Based on the differences in elements in the main tension sequence and the degree of tension change, the tension anomaly is obtained;

[0010] The wire tension monitoring results of the wire stranding machine are obtained based on the tension abnormality.

[0011] Furthermore, the specific method of decomposing the strand tension sequence into several component sequences includes:

[0012] The strand tension sequence is decomposed by EMD algorithm to obtain several component sequences.

[0013] Furthermore, the frequency index of the component sequence is obtained according to the order in which the component sequence is obtained, and the specific method includes:

[0014]

[0015] In the formula, For the The frequency index of the component sequence; For the The number of component sequences that are decomposed from the strand tension sequence; is the frequency hyperparameter.

[0016] Furthermore, the possible degree of the main tension of the component sequence is obtained according to the frequency index of the component sequence, the similarity between the component sequence and the strand tension sequence, and the disorder of the component sequence, including the specific method of:

[0017] The least square method is used to fit the strand tension sequence to obtain a fitted tension sequence; for any component sequence, the DTW distance between the component sequence and the fitted tension sequence is recorded as the difference index of the component sequence;

[0018] No. The possible degree of principal tension of a component sequence is calculated as:

[0019]

[0020] In the formula, For the The possible degree of principal tension in the component sequence; For the The entropy value of the component sequence; For the The frequency index of the component sequence; For the The difference index of the component sequences; is a hyperparameter; is an exponential function with a natural constant as its base.

[0021] Furthermore, the main tension sequence is obtained by screening the possible degree of main tension of the component sequence, including the specific method of:

[0022] The component sequence with the greatest possible degree of principal tension is recorded as the principal tension sequence.

[0023] Furthermore, the real-time frequency sequence of the component sequence is obtained, and the specific method includes:

[0024] Perform short-time Fourier transform on each component sequence respectively. For any component sequence, obtain the frequency distribution sequence of the last time window in the short-time Fourier transform, which is recorded as the real-time frequency sequence of the component sequence.

[0025] Furthermore, the method of obtaining several reference frequencies of the main tension sequence according to the amplitudes corresponding to the main tension sequence and other component sequences at the same frequency value includes the following specific methods:

[0026] For any frequency value, obtain the maximum amplitude value corresponding to the frequency value of the real-time frequency sequence of all component sequences except the main tension sequence, and record it as the reference amplitude of the frequency value; if the amplitude corresponding to the frequency value of the real-time frequency sequence of the main tension sequence is greater than the reference amplitude of the frequency value, then the frequency value is recorded as the reference frequency.

[0027] Furthermore, the tension variation degree is obtained according to the number of reference frequencies, the local fluctuation of the main tension sequence and the distribution of the real-time frequency sequence of the main tension sequence at the reference frequency, including the specific method of:

[0028] The maximum value of the amplitude corresponding to all reference frequencies in the real-time frequency sequence of the main tension sequence is recorded as the main distribution degree;

[0029] The product of the variance of all elements of the main tension sequence in the last time window, the main distribution degree and the number of reference frequencies is recorded as the tension change index; the linear normalization result of the tension change index is recorded as the tension change degree.

[0030] Furthermore, the tension anomaly is obtained according to the difference of elements in the main tension sequence and the tension change degree, and the specific method includes:

[0031]

[0032] In the formula, It is abnormal tension; is the degree of tension change; is the maximum value of all elements in the main tension sequence; is the last element value in the main tension sequence; is an exponential function with a natural constant as its base.

[0033] The present invention also proposes a wire stranding tension monitoring system for a wire stranding machine, the system comprising a memory, a processor, and a computer program stored in the memory and running on the processor, and the processor implements the steps of the above method when executing the computer program.

[0034] The beneficial effects of the present invention are as follows: in the stranded wire tension sequence, in addition to the main tension sequence mainly composed of the actual tension of the stranded wire, several component sequences composed of equipment environmental noise are superimposed on the main tension sequence. The present invention decomposes the stranded wire tension sequence into several component sequences through the difference in frequency between the main tension sequence and other component sequences, and then screens out the main tension sequence, reducing the influence of the component sequence composed of equipment environmental noise on the stranded wire tension monitoring; since the present invention needs to detect the stranded wire tension in real time, it is necessary to judge the main factor causing the tension change. The present invention obtains the reference frequency, obtains the tension change degree according to the number of reference frequencies, the local fluctuation of the main tension sequence and the distribution of the real-time frequency sequence of the main tension sequence at the reference frequency, and judges whether the main factor causing the tension change is the change of the actual tension of the stranded wire; when monitoring the stranded wire tension of the stranding machine according to the main tension sequence, the present invention adjusts the abnormal judgment process of the main tension sequence according to the tension change degree, and obtains the stranded wire tension monitoring result of the stranding machine. So far, the present invention analyzes the tension abnormality through the tension change degree, and improves the accuracy of the stranded wire tension monitoring result of the stranding machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0036] Figure 1 A schematic flow chart of a method for monitoring the tension of a stranding machine provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] See also Figure 1 , which shows a flow chart of a method for monitoring the tension of a stranding machine provided by an embodiment of the present invention, the method comprising the following steps:

[0039] Step S001, obtaining a strand tension sequence; decomposing the strand tension sequence into a plurality of component sequences.

[0040] It should be noted that the purpose of this embodiment is to analyze the tension data obtained by the strain gauge, reduce the impact of the equipment environment on the tension data measurement, and monitor the wire tension of the wire twisting machine, so the wire tension data of the wire twisting machine is first obtained.

[0041] It should be further explained that when the stranded wire is subjected to external force, it will be stretched or compressed. When the stranded wire is deformed, the resistance of the strain gauge will change. Using the bridge circuit and signal processing technology, this change can be converted into a measurable electrical signal, thereby calculating the tension of the stranded wire.

[0042] Specifically, a suitable strain gauge is selected according to the material and diameter of the stranded wire; a suitable cleaning agent is used to thoroughly clean the surface of the stranded wire to remove oil and dust to ensure good bonding; the strain gauge is evenly bonded to the stress-bearing part of the stranded wire to ensure that it is in close contact with the surface of the stranded wire, and a special adhesive is used to prevent the generation of bubbles; the strain gauge is connected to a Wheatstone bridge circuit to obtain a strain signal through a balanced measurement of the bridge; a signal amplifier is connected to enhance the weak signal output by the strain gauge; the stranded wire tension value is collected once every 1 second, and the time series consisting of the stranded wire tension values ​​collected at all times is recorded as a stranded wire tension sequence.

[0043] It should be noted that in the process of measuring the tension of the stranded wire through the stress gauge, because the force applied to the stranded wire changes linearly and does not change suddenly, the monitored stranded wire tension value is also relatively stable and does not change significantly; while the vibration of the equipment and cables has a high frequency and poor signal regularity, so when distinguishing the stranded wire tension from the equipment environment noise, it is mainly based on the frequency change of the stranded wire tension sequence and the regularity of the signal. Therefore, the stranded wire tension sequence is frequency decomposed, and then the main tension sequence is determined according to the sequence change after decomposition, which can reduce the interference of noise caused by the equipment environment, so that the stranded wire tension can be accurately monitored.

[0044] Specifically, the strand tension sequence is decomposed by an EMD algorithm to obtain several component sequences; wherein the EMD algorithm is a well-known technology, and the specific method is not introduced here.

[0045] Step S002, obtaining a frequency index of the component sequence according to the order in which the component sequence is obtained; obtaining a possible degree of main tension of the component sequence according to the frequency index of the component sequence, the similarity between the component sequence and the strand tension sequence, and the disorder of the component sequence; and obtaining a main tension sequence by screening according to the possible degree of main tension of the component sequence.

[0046] It should be noted that the component sequence is to separate the different frequency components of the stranded wire tension sequence through the local fluctuation characteristics. Therefore, among the several component sequences obtained, the main tension sequence mainly exists in a certain component sequence, while other component sequences are caused by the equipment environment noise, so the main tension sequence is obtained in the component sequence.

[0047] It should be further explained that since the component sequences decomposed by the EMD algorithm are arranged according to frequency, the component sequences separated earlier have higher frequencies, and the component sequences separated later have lower frequencies, so the frequency index of each component sequence is obtained.

[0048] Specifically, The method for obtaining the frequency index of a component sequence is:

[0049]

[0050] In the formula, For the The frequency index of the component sequence; For the The number of component sequences that are decomposed from the strand tension sequence; is the frequency hyperparameter. Let's take this as an example.

[0051] It should be noted that, because the main tension sequence represents the changing trend and direction of the actual tension of the stranded wire, and the component sequence caused by the equipment environmental noise is superimposed on the main tension sequence, the change of the main tension sequence is similar to the stranded wire tension sequence before decomposition.

[0052] Specifically, the least squares method is used to fit the strand tension sequence to obtain a fitted tension sequence; for any component sequence, the DTW distance between the component sequence and the fitted tension sequence is recorded as the difference index of the component sequence; wherein, the least squares method and the calculation method of the DTW distance are well-known technologies, and the specific method will not be introduced here.

[0053] It should be noted that, since the actual tension of the stranded wire is linear and will not change suddenly, the main tension sequence is relatively stable, that is, the entropy value is small; the frequencies of the component sequences belonging to the equipment environment noise are relatively high, so the component sequences that are decomposed earlier, that is, the sequences with higher frequency indexes of the component sequences, are more likely to belong to the component sequences of the equipment environment noise; and since the changes in the main tension sequence are similar to the stranded wire tension sequence before decomposition, the component sequences with smaller difference indexes are more likely to be the main tension sequence.

[0054] Specifically, The possible degree of principal tension of a component sequence is calculated as:

[0055]

[0056] In the formula, For the The possible degree of principal tension in the component sequence; For the The entropy value of the component sequence; For the The frequency index of the component sequence; For the The difference index of the component sequences; To prevent the hyperparameter from having a denominator of 0, this embodiment uses to give a narrative; is an exponential function with a natural constant as its base.

[0057] Furthermore, the component sequence with the largest possible degree of principal tension is recorded as the principal tension sequence.

[0058] Step S003, obtaining the real-time frequency sequence of the component sequence; obtaining several reference frequencies of the main tension sequence according to the corresponding amplitudes of the main tension sequence and other component sequences at the same frequency value; obtaining the tension change degree according to the number of reference frequencies, the local fluctuation of the main tension sequence and the distribution of the real-time frequency sequence of the main tension sequence at the reference frequency.

[0059] It should be noted that in order to further reduce the interference of equipment environmental noise, the frequency information of the main tension sequence is obtained. The frequency information is a statistic of the signal frequency change. The obtained frequency information is caused by the tension of the stranded wire on the stress gauge. However, there may be other noise frequencies. Therefore, it is inaccurate to analyze the change of the force on the stress gauge based only on the frequency information of the main tension sequence. It is also necessary to analyze the change relationship between the main tension sequence and other component sequences to determine the impact of the change on the stress gauge.

[0060] Specifically, short-time Fourier transform is performed on each component sequence respectively. Since the purpose of this embodiment is to monitor the wire twisting tension of the wire twisting machine in real time, for any component sequence, the frequency distribution sequence of the last time window in the short-time Fourier transform is obtained, which is recorded as the real-time frequency sequence of the component sequence, wherein short-time Fourier transform is a well-known technology and the specific method is not introduced here; wherein the real-time frequency sequence includes the amplitude of the component sequence corresponding to each frequency value.

[0061] It should be noted that when judging the abnormality of the strand tension based on the main tension sequence, it is necessary to first determine whether the factor causing the change in the main tension sequence is caused by the change in the actual strand tension rather than the equipment environment noise, so the influencing component of the current actual strand tension is judged.

[0062] Specifically, for any frequency value, obtain the maximum amplitude value of the real-time frequency sequence of all component sequences except the main tension sequence at the frequency value, which is recorded as the reference amplitude value of the frequency value; if the amplitude value of the real-time frequency sequence of the main tension sequence at the frequency value is greater than the reference amplitude value of the frequency value, then the frequency value is recorded as the reference frequency.

[0063] It should be further explained that if the maximum amplitude in the real-time frequency sequence of the main tension sequence is relatively large, it means that the distribution of the frequency value corresponding to the maximum amplitude of the main tension sequence is relatively wide; if the fluctuation degree of the main tension sequence is greater, it means that the degree of change of the main tension sequence is greater. At the same time, if the number of reference frequencies is more, it means that the main tension sequence is the main factor of the current change of the main tension sequence.

[0064] Specifically, the maximum value of the amplitude corresponding to all reference frequencies in the real-time frequency sequence of the main tension sequence is recorded as the main distribution degree;

[0065] The product of the variance of all elements of the main tension sequence in the last time window, the main distribution degree and the number of reference frequencies is recorded as the tension change index; the linear normalization result of the tension change index is recorded as the tension change degree; wherein the normalization object is all the tension change indices in the historical monitoring process.

[0066] Step S004: Obtain tension anomaly according to the difference of elements in the main tension sequence and the tension variation degree.

[0067] It should be noted that the tension change degree of the main tension sequence describes the proportion of the frequency caused by the actual tension of the strand in the signal, and thus in the process of monitoring the tension of the strand, it can be determined whether the signal with the greatest influence is the actual tension of the strand. The change in the tension of the strand indicates that the strand has a large degree of deformation when subjected to force, and the monitored signal will undergo a sudden change. Therefore, the abnormality of the tension is obtained based on the change in the main tension sequence.

[0068] It should be further explained that, if the degree of tension change is greater, it indicates that the change of the current main tension sequence is mainly caused by the actual tension of the strand. If the difference between the latest element value of the main tension sequence and the maximum value of all elements in the main tension sequence is smaller, it means that the possibility of abnormal tension value of the strand is greater.

[0069] Specifically, the calculation method of tension abnormality is:

[0070]

[0071] In the formula, It is abnormal tension; is the degree of tension change; is the maximum value of all elements in the main tension sequence; It is the last element value in the main tension sequence, that is, the latest element value of the main tension sequence; is an exponential function with a natural constant as its base.

[0072] Step S005: obtaining a wire tension monitoring result of the wire stranding machine according to the tension abnormality.

[0073] It should be noted that after obtaining the real-time tension anomaly, it is necessary to make an abnormality judgment on the current stranded wire tension according to the tension anomaly.

[0074] Specifically, if the tension abnormality is greater than the tension abnormality threshold The current stranded wire tension is abnormal, an alarm is triggered, and the stranded wire is manually inspected. The specific inspection method is: by applying tension to both sides of the stranded wire, the tension increases slowly. The maximum tension values ​​of different types of stranded wires are different. During the process of increasing tension, the strain gauge is used to monitor the change of the stranded wire tension. If the maximum tension of the stranded wire model is not reached, it indicates an abnormality, indicating that there is a problem with the stranded wire production quality, and the stranded wire is replaced; if the tension abnormality is less than the tension abnormality threshold , the current strand tension is normal, and the strand tension continues to be monitored.

[0075] This embodiment adopts Model to present inverse proportional relationship and normalization, As the input of the model, the implementer can set the inverse proportional function and normalization function according to the actual situation.

[0076] Another embodiment of the present invention provides a wire stranding tension monitoring system for a wire stranding machine, the system comprising a memory, a processor, and a computer program stored in the memory and running on the processor, and when the processor executes the computer program, the above method steps S001 to S005 are implemented.

[0077] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for monitoring the tension of a stranding machine, characterized in that: The method comprises the following steps: Obtaining a strand tension sequence; wherein the strand tension sequence includes a strand tension value at each moment; decomposing the strand tension sequence into a plurality of component sequences; The frequency index of the component sequence is obtained according to the order in which the component sequence is obtained; the possible degree of the main tension of the component sequence is obtained according to the frequency index of the component sequence, the similarity between the component sequence and the strand tension sequence, and the disorder of the component sequence; the main tension sequence is obtained by screening according to the possible degree of the main tension of the component sequence; Acquire a real-time frequency sequence of a component sequence; the real-time frequency sequence includes the amplitude of the component sequence corresponding to each frequency value; obtain several reference frequencies of the main tension sequence according to the amplitudes corresponding to the main tension sequence and other component sequences at the same frequency value; obtain the tension change degree according to the number of reference frequencies, the local fluctuation of the main tension sequence and the distribution of the real-time frequency sequence of the main tension sequence at the reference frequency; Based on the differences in elements in the main tension sequence and the degree of tension change, the tension anomaly is obtained; The wire tension monitoring results of the wire stranding machine are obtained based on the tension abnormality.

2. A method for monitoring the tension of a stranding machine according to claim 1, characterized in that: The specific method of decomposing the strand tension sequence into a plurality of component sequences includes: The strand tension sequence is decomposed by EMD algorithm to obtain several component sequences.

3. A method for monitoring the tension of a stranding machine according to claim 1, characterized in that: The specific method of obtaining the frequency index of the component sequence according to the order in which the component sequence is obtained is as follows: In the formula, For the The frequency index of the component sequence; For the The number of component sequences that are decomposed from the strand tension sequence; is the frequency hyperparameter.

4. A method for monitoring the tension of a stranding machine according to claim 1, characterized in that: The method of obtaining the possible degree of the main tension of the component sequence according to the frequency index of the component sequence, the similarity between the component sequence and the strand tension sequence, and the disorder of the component sequence includes the following specific methods: The least square method is used to fit the strand tension sequence to obtain a fitted tension sequence; for any component sequence, the DTW distance between the component sequence and the fitted tension sequence is recorded as the difference index of the component sequence; No. The possible degree of principal tension of a component sequence is calculated as: In the formula, For the The possible degree of principal tension in the component sequence; For the The entropy value of the component sequence; For the The frequency index of the component sequence; For the The difference index of the component sequences; is a hyperparameter; is an exponential function with a natural constant as its base.

5. A method for monitoring the tension of a stranding machine according to claim 1, characterized in that: The method of obtaining the main tension sequence by screening the possible degree of the main tension of the component sequence includes the following specific methods: The component sequence with the greatest possible degree of principal tension is recorded as the principal tension sequence.

6. A method for monitoring the tension of a stranding machine according to claim 1, characterized in that: The specific method of obtaining the real-time frequency sequence of the component sequence includes: Perform short-time Fourier transform on each component sequence respectively. For any component sequence, obtain the frequency distribution sequence of the last time window in the short-time Fourier transform, which is recorded as the real-time frequency sequence of the component sequence.

7. A method for monitoring the tension of a stranding machine according to claim 1, characterized in that: The specific method of obtaining several reference frequencies of the main tension sequence according to the corresponding amplitudes of the main tension sequence and other component sequences at the same frequency value is as follows: For any frequency value, obtain the maximum amplitude value corresponding to the frequency value of the real-time frequency sequence of all component sequences except the main tension sequence, and record it as the reference amplitude of the frequency value; if the amplitude corresponding to the frequency value of the real-time frequency sequence of the main tension sequence is greater than the reference amplitude of the frequency value, then the frequency value is recorded as the reference frequency.

8. A method for monitoring the tension of a stranding machine according to claim 6, characterized in that: The specific method of obtaining the tension variation degree according to the number of reference frequencies, the local fluctuation of the main tension sequence and the distribution of the real-time frequency sequence of the main tension sequence at the reference frequency includes: The maximum value of the amplitude corresponding to all reference frequencies in the real-time frequency sequence of the main tension sequence is recorded as the main distribution degree; The product of the variance of all elements of the main tension sequence in the last time window, the main distribution degree and the number of reference frequencies is recorded as the tension change index; the linear normalization result of the tension change index is recorded as the tension change degree.

9. A method for monitoring the tension of a stranding machine according to claim 1, characterized in that: The specific method of obtaining the tension anomaly according to the difference of elements in the main tension sequence and the tension change degree is as follows: In the formula, It is abnormal tension; is the degree of tension change; is the maximum value of all elements in the main tension sequence; is the last element value in the main tension sequence; is an exponential function with a natural constant as its base.

10. A wire stranding tension monitoring system for a wire stranding machine, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the steps of a wire stranding tension monitoring method for a wire stranding machine as described in any one of claims 1 to 9 are implemented.

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