Twisting preparation method of unshielded data transmission cable

Abstract

The invention relates to the technical field of cable stranding preparation, in particular to a stranding preparation method of an unshielded data transmission cable, and the method comprises the steps: carrying out the preprocessing of a metal conductor, and coating the metal conductor with an insulating layer, and forming an insulating wire core; a plurality of insulated wire cores are twisted into wire pairs, and the twisting pitch is dynamically adjusted in the twisting process; and combining the wire pairs with the filling material to form a cable core, wrapping and fixing the cable core, and extruding a coating sheath on the outer layer to form a complete cable. The invention aims to dynamically adjust the wire pair twisting pitch, dynamically compensate the influence of the pitch deviation on the crosstalk performance, and realize the accurate control of the pitch deviation.

Description

Technical Field

[0001] This application relates to the field of cable stranding preparation technology, specifically to a method for stranding an unshielded data transmission cable. Background Technology

[0002] Unshielded data transmission cables are a type of cable widely used in high-speed data transmission scenarios. Their core structure consists of multiple pairs of insulated copper conductors twisted together at a specific pitch, with only a single insulating sheath covering the outer layer. They lack a metallic shielding layer and offer advantages such as low cost, good flexibility, and convenient installation. The conductors are typically made of annealed copper wire, and the insulation layer is relatively thin. The differential design of the twisting pitch between the conductor pairs is crucial for suppressing crosstalk caused by electromagnetic coupling between pairs, making it a key technical parameter for achieving signal integrity.

[0003] The twisting pitch refers to the distance a single wire travels in one revolution along the twisted wire axis. Because it lacks a shielding layer, it is more sensitive to pitch deviations. Excessive pitch deviation leads to uneven characteristic impedance, causing signal reflection and attenuation, resulting in crosstalk, increased bit error rate, and exacerbated transmission delay. Existing patent "CN222145893U A Device for Controlling Twisted Pair Pitch Deviation" uses a speed-measuring proximity switch to monitor the wire release speed in real time. It uses the mismatch between the wire release speed and the bow rotation speed when pitch is abnormal to determine the pitch deviation, indirectly linking speed and pitch, thus achieving early warning of pitch abnormalities. Existing patent "CN114660748B Optical Cable Twisting Control Method, Device, Electronic Equipment, and Storage Medium" identifies possible deviation intervals during reciprocating twisting, dynamically adjusts the twisting pitch compensation amplitude, ensures that the pitch difference in each interval is within a preset range, and uses a segmented compensation strategy to improve pitch uniformity.

[0004] However, existing technologies do not consider that high-order harmonic interference generated by equipment vibration will act on the stranding system through mechanical coupling, causing the actual stranding pitch to deviate from the set value, ultimately resulting in pitch non-uniformity. Therefore, the technical problem to be solved in this application is: how to separate the key harmonic components in equipment vibration in real time during the multi-pair stranding process of unshielded data cables, dynamically compensate for the impact of pair pitch deviation on crosstalk performance, adjust the pay-off tension, and achieve precise control of pitch deviation. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides a stranding method for preparing an unshielded data transmission cable, thereby resolving the existing issues.

[0006] The stranding method for manufacturing an unshielded data transmission cable according to this application adopts the following technical solution: One embodiment of this application provides a method for stranding an unshielded data transmission cable, the method comprising the following steps: The metal conductor is pretreated and covered with an insulating layer to form an insulated wire core; Multiple insulated wire cores are twisted into a pair, and the twisting pitch is dynamically adjusted during the twisting process; the method of dynamic adjustment is as follows: The tension signals of each wire pair and the vibration signals of the equipment in all directions are collected in real time during the multi-wire pair twisting process. The tension signal is used as a relevant constraint term of the vibration signal to extract the higher-order harmonic components affecting the pitch from the vibration signal using the blind source separation algorithm; Furthermore, by utilizing higher-order harmonic components and the tension of the line pairs, a pitch deviation prediction model for each line pair is constructed. The pitch standard deviation of all line pairs at the current moment is analyzed using the pitch deviation prediction model of all line pairs. The difference in predicted values ​​between the pitch deviation prediction models of all line pairs is used to calculate the near-end crosstalk deterioration between adjacent line pairs at the current moment. The weighted sum of the near-end crosstalk deterioration between all adjacent line pairs at the current moment and the pitch standard deviation is used as the objective function of model predictive control. The pitch deviation prediction model is used as the prediction model of model predictive control to adjust the pay-off tension and control the pitch deviation through model predictive control. The wire pairs are combined with filler material to form the cable core. After the cable core is wrapped and fixed, an outer sheath is extruded to form a complete cable.

[0007] Preferably, the tension signal of each wire pair is the average value of the tension of the two wire cores at each acquisition time.

[0008] Preferably, the step of using the tension signal as a relevant constraint term of the vibration signal to extract the higher-order harmonic components affecting the pitch from the vibration signal using the blind source separation algorithm includes: constructing a mixed signal matrix from the vibration signals in all directions and the tension signals of all line pairs, using it as the input of the fast independent component analysis algorithm, and reconstructing the objective function of the fast independent component analysis algorithm using the correlation between the tension signal and the vibration signal, so as to extract the higher-order harmonic components from the vibration signal.

[0009] Preferably, the higher-order harmonic components include time-domain harmonic components of the second and third harmonics.

[0010] Preferably, the method for constructing the pitch deviation prediction model is as follows: the pitch deviation prediction model for the i-th line pair at time t is: ;in, This represents the predicted pitch deviation value of the i-th line pair at time t. This represents the tension of the i-th wire pair at time t. , Let represent the second and third harmonic components extracted at time t, respectively. , and These represent the preset fitting coefficients.

[0011] Preferably, the method for analyzing the standard deviation of the pitch is as follows: ,in, Let n represent the standard deviation of the pitch of all line pairs at time t, and n represent the number of line pairs. This represents the pitch of the i-th line pair at time t-1. This represents the predicted pitch deviation value of the i-th line pair at time t. This represents the average target pitch for all line pairs.

[0012] Preferably, the method for calculating the near-end crosstalk degradation is as follows: ,in, This represents the near-end crosstalk deterioration between adjacent line pairs i and j at time t. Represents the logarithmic function with base 10. , These represent the target pitches of the i-th and j-th line pairs, respectively. , These represent the predicted pitch deviation values ​​for the i-th and j-th line pairs at time t, respectively. This represents the preset coupling coefficient.

[0013] Preferably, the target pitch is the preset initial pitch of the corresponding line pair.

[0014] Preferably, the filler material is polypropylene tear cord, and the sheath material is low-density polyethylene.

[0015] Preferably, the wrapping material is a polyester tape or non-woven fabric with a thickness of 0.05~0.1mm.

[0016] This application has at least the following beneficial effects: This application improves the objective function of FastICA based on the correlation between vibration and tension signals to decompose mixed vibration signals, enabling more accurate extraction of key harmonic components. Each line pair is modeled separately based on the key harmonic components and tension, and the pitch deviation is calculated. The tension of the line pair is then adjusted according to the pitch deviation. Multi-objective optimization is performed based on pitch deviation and crosstalk degradation to reduce the correlation of pitch deviations between line pairs and prevent crosstalk from worsening due to pitch synchronization fluctuations. Attached Figure Description

[0017] To more clearly illustrate the technical solutions and advantages in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A flowchart illustrating a stranding method for preparing an unshielded data transmission cable provided in this application; Figure 2 This application provides a flowchart of a method for dynamically adjusting the twisting pitch during the twisting process. Detailed Implementation

[0019] To further illustrate the technical means and effects adopted by this application to achieve the intended purpose of the invention, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a stranding preparation method for an unshielded data transmission cable proposed in this application. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0021] The following describes in detail, with reference to the accompanying drawings, a specific scheme for the stranding preparation method of an unshielded data transmission cable provided in this application.

[0022] One embodiment of this application provides a method for preparing an unshielded data transmission cable by stranding.

[0023] Specifically, the following method for stranding and preparing an unshielded data transmission cable is provided; please refer to [link / reference]. Figure 1 The method includes the following steps: The metallic conductor is pretreated and covered with an insulating layer to form an insulated wire core; Multiple insulated wire cores are twisted into a pair, and the twisting pitch is dynamically adjusted during the twisting process; the method of dynamic adjustment is as follows: The tension signals of each wire pair and the vibration signals of the equipment in all directions are collected in real time during the multi-wire pair twisting process. The tension signal is used as a relevant constraint term of the vibration signal to extract the higher-order harmonic components affecting the pitch from the vibration signal using the blind source separation algorithm; Furthermore, by utilizing higher-order harmonic components and the tension of the line pairs, a pitch deviation prediction model for each line pair is constructed. The pitch standard deviation of all line pairs at the current moment is analyzed using the pitch deviation prediction model of all line pairs. The difference in predicted values ​​between the pitch deviation prediction models of all line pairs is used to calculate the near-end crosstalk deterioration between adjacent line pairs at the current moment. The weighted sum of the near-end crosstalk deterioration between all adjacent line pairs at the current moment and the pitch standard deviation is used as the objective function of model predictive control. The pitch deviation prediction model is used as the prediction model of model predictive control to adjust the pay-off tension and control the pitch deviation through model predictive control. The wire pairs are combined with filler material to form the cable core. After the cable core is wrapped and fixed, an outer sheath is extruded to form a complete cable.

[0024] Example 1 S1: The metal conductor is pretreated and covered with an insulating layer to form an insulated core.

[0025] The metal conductor in this application is a solid copper conductor. The pretreatment of the metal conductor includes wire drawing, which is carried out by drawing the wire to a diameter of 0.50mm±0.01mm (24AWG) through multiple passes using a wire drawing machine, and then annealing is carried out by continuous annealing process (temperature 350, time 30s).

[0026] Using a high-speed extruder, an insulated wire core is formed by insulating the material with a right-angle die. The insulation material is high-density polyethylene (HDPE) with a thickness of 0.25mm ± 0.02mm. The barrel temperature is set to 180℃ and the die temperature is set to 210℃.

[0027] S2: Multiple insulated wire cores are twisted into wire pairs, and the twisting pitch is dynamically adjusted during the twisting process.

[0028] This application uses a twisting machine to simultaneously twist eight independently insulated wire cores, combining two insulated wire cores into an independent wire pair. The twisting machine operates at high speeds (1500~3000 RPM). After prolonged use and wear, its core rotating components (such as the winch, spindle, and pay-off reel) may experience mass eccentricity. Therefore, the centrifugal force generated by this eccentric mass during high-speed operation creates a periodic excitation force with a frequency consistent with the rotational speed. Due to the nonlinear stiffness of the mechanical structure, the excitation force undergoes distortion during transmission, giving rise to higher-order components.

[0029] High-order harmonic interference can act on the stranding system through mechanical coupling, disrupting the dynamic balance between the wire tension and the winding speed. The high-frequency components of high-order harmonics are prone to resonate with the inherent modes of the stranding equipment, causing instantaneous micro-vibrations in components such as the wire reel and tension sensor. This results in periodic fluctuations in the core tension. For unshielded data cables, the core insulation layer is thin and lacks the rigid support of the shielding layer. Tension fluctuations directly lead to real-time changes in the amount of conductor stretching or slack during stranding, causing the actual stranding pitch to deviate from the set value, ultimately resulting in pitch non-uniformity.

[0030] In this embodiment, the cable has a four-pair, eight-core structure, with each pair of cores twisted together at a different pitch. The pitch difference between the pairs is greater than 10%, which suppresses crosstalk through pitch differentiation. In this embodiment, the target pitches for the four pairs are 25mm, 30mm, 35mm, and 40mm, respectively. The aforementioned high-frequency harmonics, transmitted through the mechanical structure, affect the tension of each pair, causing synchronous fluctuations in the pitch deviations of different pairs. The similarity in the direction and amplitude of pitch fluctuations between adjacent pairs disrupts the pitch differentiation, leading to worsened crosstalk. The tension range for a single pair of cores is 5~15N; in this embodiment, the tension is set to 5N.

[0031] The flowchart of the method for dynamically adjusting the stranding pitch during the stranding process in this application is attached. Figure 2 As shown, specifically: S201: Real-time acquisition of tension signals of each wire pair and vibration signals of the equipment in all directions during the multi-wire pair twisting process.

[0032] A miniature fiber Bragg grating (FBG) tension sensor was used to collect the tension of each wire core during the stranding process. The sensor was installed vertically at the guide wheel at the wire release end of each pair of wire cores, with the sensor axis aligned with the tension direction of the wire core. The tension of each pair of wire cores was taken as the average of the tension of the two wire cores. A total of four tension signals from four pairs of wire cores were collected.

[0033] Three-dimensional IEPE accelerometers are used to collect equipment vibration signals during the stranding process. Three-dimensional IEPE accelerometers (bandwidth 0.5~1000Hz) are deployed in key parts (spindle bearing housing, cable reel support or reducer output shaft) to collect 5th harmonic vibration signals (corresponding to the 40~250Hz frequency band when the data cable stranding speed is 1500~3000RPM), and a total of three vibration signals in three directions are collected.

[0034] Data acquisition is triggered with a period of 1ms to ensure data synchronization. The original vibration signal is filtered by a sliding window (window length 5ms) to remove power frequency (50Hz) and switching power supply noise (100Hz) and output a standardized data frame containing a timestamp.

[0035] S202: The tension signal is used as a relevant constraint term of the vibration signal in order to extract the higher-order harmonic components that affect the pitch from the vibration signal using the blind source separation algorithm.

[0036] The natural frequency of rotating components often coincides with 2 to 3 times the fundamental frequency, forming structural resonance. This resonance effect makes the energy of the 2nd and 3rd harmonic vibrations much higher than other harmonics, becoming the main cause of the disruption of the stranding stability of the wire pair. In order to avoid the influence of irrelevant components such as environmental noise, the 2nd and 3rd harmonic signals are first extracted from the original vibration signal.

[0037] Traditional blind source separation algorithms typically rely solely on the statistical independence assumption of multi-channel vibration signals, decomposing the mixed signal into several independent components and outputting uncorrelated independent vibration modes. This makes it difficult to accurately identify harmonic interference directly related to pitch deviation. However, the tension signal directly reflects the stress state of the core during stranding and is a core process parameter for pitch formation. This application uses the tension signal as a reference anchor point, constraining the correlation between vibration components and the tension signal to force the blind source separation algorithm to retain only vibration modes strongly correlated with tension fluctuations. The specific steps are as follows: This embodiment uses the FastICA (Fast Independent Component Analysis) algorithm to separate the mixed signal matrix. In this embodiment, the first three rows of the mixed signal matrix are set as the vibration signals of the device in three directions, and the last four rows are set as the tension signals of four line pairs. The seven rows correspond to the seven dimensions of the mixed signal matrix, and the column dimension is 1 second, that is, 1000 sampling periods. The FastICA algorithm is a well-known technology.

[0038] The objective function of the traditional FastICA algorithm is to maximize negative entropy. This application incorporates a tension-related constraint term, thus the objective function becomes... ,in (This represents the term that maximizes negative entropy, i.e., the objective function of the traditional FastICA algorithm). This represents the preset correlation coefficient weight, ranging from 0.6 to 1.5. In this embodiment, the value is 0.8, and m represents the number of independent components. Let j represent the j-th independent component. This represents the tension signal of the i-th wire pair. () indicates the function for calculating the Pearson correlation coefficient.

[0039] In the process of separating the input mixed signal matrix by the FastICA algorithm, the mixed signal matrix is ​​first centered and whitened to obtain a 7-dimensional whitening matrix; a 7-dimensional orthogonal vector is randomly generated and updated through fixed-point iteration. After each iteration, the orthogonal vector is Gram-Schmidt orthogonalized to ensure that the separated components are independent. After stopping the iteration, a 7-dimensional independent component matrix is ​​output, with each row corresponding to an independent component.

[0040] The independent components whose absolute values ​​of the Pearson correlation coefficients with any tension signal are greater than or equal to a preset correlation threshold are retained; in this embodiment, the preset correlation threshold is set to 0.5, but the implementer can set it according to the actual situation.

[0041] For each retained independent component, perform FFT (Fast Fourier Transform) to obtain the frequency domain amplitude spectrum and phase spectrum, and extract the amplitude and phase corresponding to the second and third harmonics (when the rotation speed is 3000 RPM, the fundamental frequency is 50 Hz, and the second and third harmonics are 100 Hz and 150 Hz, respectively). The second and third harmonics of all independent components are vector superimposed and synthesized respectively. The amplitude and phase of the vector superimposed second and third harmonics are inversely FFTed to obtain the time domain harmonic signals of the second and third harmonics, that is, to obtain the higher-order harmonic components that affect the pitch from the vibration signal.

[0042] S203: Establish a pitch deviation prediction model for a single pair of wire cores, and calculate the pitch compensation amount for each pair in combination with the crosstalk suppression requirements of multiple wire pairs.

[0043] Factors such as vibration of stranding equipment and differences in the inertia of the pay-off reel can cause different harmonic interference intensities and phases to be experienced by different wire pairs. Different wire pairs respond differently to the same interference source due to different stranding pitch design values, so it is necessary to model different wire pairs separately.

[0044] Based on this, a prediction model is constructed for the pitch deviation of each line pair. Taking the pitch deviation prediction model of the i-th line pair at time t as an example: ;in, This represents the predicted pitch deviation value of the i-th line pair at time t. This represents the tension of the i-th wire pair at time t. , Let represent the second and third harmonic components extracted at time t, respectively. , and These represent preset fitting coefficients. In this embodiment, the pitch deviations corresponding to 100 sets of different tension and vibration data are obtained by fitting using the orthogonal experimental method.

[0045] It should be understood that tension directly determines the degree of stretching of the wire core. When tension changes, the actual length of the wire pair changes, thus affecting the stranding pitch. When tension increases, the wire core is stretched, and the pitch may decrease; when tension decreases, the wire core shortens, and the pitch may increase. The coefficients determined through data fitting reflect the pitch deviation caused by a unit change in tension. Equipment vibration generates a second harmonic vibration component, which is transmitted to the wire pair through mechanical coupling, causing periodic changes in its motion state and resulting in pitch deviation. Third harmonics are usually derived from the nonlinear characteristics or complex vibration modes of the equipment. They also interfere with the stable stranding of the wire pair, and their higher frequency has a more significant impact on high-frequency fluctuations in the pitch. The coefficients determined through data fitting reflect the relationship between the frequency component and the pitch deviation.

[0046] By employing a linear superposition method, the effects of tension and vibration harmonics at two key frequencies on pitch deviation are comprehensively considered. Through fitting actual data or experimental determination, a quantitative relationship between pitch deviation and physical influencing factors is established, providing a theoretical basis for pitch deviation prediction and control.

[0047] The above model can only control the pitch deviation of a single wire pair when predicting the pitch deviation of the wire pair. However, when multiple wire pairs are combined into a cable, the pitch difference between different wire pairs must also be considered in order to suppress crosstalk. This application uses model predictive control (MPC) for multi-objective optimization.

[0048] The objective function in this application is to minimize the weighted sum of the pitch standard deviation and the total amount of crosstalk deterioration. This is because in the stranding scenario of unshielded data cables, if only the pitch height is kept consistent, the pitch of adjacent wire pairs may approach the same value, causing pitch resonance. Due to the similar stranding frequency, strong electromagnetic coupling occurs between wire pairs, which in turn aggravates crosstalk. Unshielded cables lack a metal shielding layer, and crosstalk between wire pairs mainly relies on pitch differentiation design to suppress it. If crosstalk is ignored and the pitch is directly optimized, it may destroy the original crosstalk suppression strategy.

[0049] The objective function is then ,in, Let t represent the objective function of the model predictive control. , These represent the preset first and second weighting coefficients, with values ​​ranging from 0 to 1. In this embodiment, the values ​​are 0.4 and 0.6 respectively (the crosstalk performance weight is higher).

[0050] in, The standard deviation of the pitch of all line pairs at time t can be expressed as: t>1, where n represents the number of line pairs. This represents the pitch of the i-th line pair at time t-1. This represents the predicted pitch deviation value of the i-th line pair at time t. This represents the average target pitch for all line pairs. The initial pitch is the target pitch for the corresponding line pair, and the current pitch prediction value is the pitch from the previous moment plus the current pitch deviation prediction value.

[0051] in, The near-end crosstalk deterioration between adjacent line pairs i and j at time t can be expressed as: ,in, Represents the logarithmic function with base 10. , These represent the target pitches of the i-th and j-th line pairs, respectively. , These represent the predicted pitch deviation values ​​for the i-th and j-th line pairs at time t, respectively. This represents the preset coupling coefficient, which is inversely proportional to the physical distance between line pairs and ranges from 0.8 to 0.9. In this embodiment, when the physical distance between the i-th and j-th line pairs is 0.5 cm, its value is 0.85.

[0052] It should be understood that pitch deviation between adjacent wire pairs will disrupt the periodicity of the stranded structure, leading to an increase in the length of the parallel segments between wire pairs, which in turn exacerbates electromagnetic coupling. The degree of disruption to stranding uniformity caused by the deviation is quantified by the ratio of the pitch deviation difference to the sum of the target pitches. A coupling coefficient inversely proportional to the physical distance between wire pairs is introduced, and the linear coupling degradation is converted into near-end crosstalk degradation in decibel form commonly used in the field of communications through logarithmic transformation, thereby establishing a direct quantitative relationship between pitch deviation and crosstalk degradation.

[0053] This application controls pitch deviation by adjusting the pay-off tension using model predictive control (MPC). The adjustment range of the pay-off tension is constrained to -1N to 1N. The prediction model of MPC in this application is a state transition equation, i.e., a pitch deviation prediction model, and the optimization objective is the objective function. The constraint is the adjustment range of the wire tension. The specific solution steps are as follows: The tension and vibration signals of each wire pair are collected in real time, and harmonic components are extracted. The pitch deviation for the next two cycles is recursively calculated using the state transition equation. Based on the predicted future deviation, the optimal control sequence (QP solver) is solved using quadratic programming (QP), which is the adjustment amount of the wire tension, to minimize the objective function while satisfying the constraints. The control quantity at the current moment is executed, and the above process is repeated in the next cycle, that is, the model is updated and re-optimized using the new measurement values.

[0054] S3: Combine the wire pairs with the filler material to form the cable core. After wrapping and fixing the cable core, extrude the outer sheath to form a complete cable.

[0055] The filling material is polypropylene tear cord, and polyester tape (PET) or non-woven fabric with a thickness of 0.05~0.1mm is used for wrapping. In this embodiment, 0.05mm polyester tape is used for wrapping. The sheath material is low-density polyethylene (LDPE), which is also extruded using an extruder. Finally, the cable model, manufacturer's name and implementation standard are printed to form a complete cable.

[0056] Example 2 In step S1 of this embodiment, the continuous annealing process is performed at a temperature of 375°C for 45 seconds. The barrel temperature is set to 170°C, and the die temperature is set to 200°C. Other aspects are the same as in the implementation method of Embodiment 1.

[0057] In step S2 of this embodiment, the wire tension is set to 10N. The rest is the same as the implementation method in Embodiment 1.

[0058] In step S3 of this embodiment, a 0.07mm polyester tape is selected for wrapping. The rest is the same as the implementation method in Embodiment 1.

[0059] Example 3 In step S1 of this embodiment, the continuous annealing process is performed at a temperature of 400°C for 60 seconds. The barrel temperature is set to 160°C, and the die temperature is set to 190°C. Other aspects are the same as in the implementation method of Embodiment 1.

[0060] In step S2 of this embodiment, the wire tension is set to 15N. The rest is the same as the implementation method in Embodiment 1.

[0061] In step S3 of this embodiment, a 0.1mm polyester tape is selected for wrapping. The rest is the same as the implementation method in Embodiment 1.

[0062] To verify the validity of this application, several comparative examples are set up, specifically: Example 1: The wire tension is set to 5N, and the tension is dynamically adjusted during the twisting process; Example 2: The wire tension is set to 10N, and the tension is dynamically adjusted during the twisting process; Example 3: The wire tension is set to 15N, and the tension is dynamically adjusted during the twisting process; Comparative Example 1: The wire tension is set to 5N and is not adjusted during the twisting process; Comparative Example 2: The wire tension is set to 10N and is not adjusted during the twisting process; Comparative Example 3: The wire tension is set to 15N and is not adjusted during the twisting process; Unless otherwise stated, the process flow and parameters of Comparative Examples 1, 2, and 3 are consistent with those of Examples 1, 2, and 3, respectively.

[0063] The comparison between the fixed tension and that of this application is shown in the table below: Table 1 Comparison of Wire Tension During Laying Out As shown in Table 1, compared with the corresponding comparative examples, Examples 1-3 exhibit significantly reduced pitch deviation, higher near-end crosstalk (NEXT) values, smaller characteristic impedance fluctuations, and a substantial decrease in insulation failure rate. This is because the dynamic adjustment extracts high-order harmonic components from equipment vibration using a blind source separation algorithm. Combined with a pitch deviation prediction model and multi-objective optimization, the dynamic adjustment of the wire tension offsets tension fluctuations caused by vibration, precisely controlling pitch differences and preventing excessive stretching or slack in the wire core. This, in turn, improves pitch uniformity, crosstalk suppression capability, and insulation reliability.

[0064] The above technical features constitute the preferred embodiment of this application, which has strong adaptability and the best implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A method for stranding and preparing an unshielded data transmission cable, characterized in that, The method includes the following steps: The metal conductor is pretreated and covered with an insulating layer to form an insulated wire core; Multiple insulated wire cores are twisted into a pair, and the twisting pitch is dynamically adjusted during the twisting process; the method of dynamic adjustment is as follows: The tension signals of each wire pair and the vibration signals of the equipment in all directions are collected in real time during the multi-wire pair twisting process. The tension signal is used as a relevant constraint term of the vibration signal to extract the higher-order harmonic components affecting the pitch from the vibration signal using the blind source separation algorithm; Furthermore, by utilizing higher-order harmonic components and the tension of the line pairs, a pitch deviation prediction model for each line pair is constructed. The pitch standard deviation of all line pairs at the current moment is analyzed using the pitch deviation prediction model of all line pairs. The difference in predicted values ​​between the pitch deviation prediction models of all line pairs is used to calculate the near-end crosstalk deterioration between adjacent line pairs at the current moment. The weighted sum of the near-end crosstalk deterioration between all adjacent line pairs at the current moment and the pitch standard deviation is used as the objective function of model predictive control. The pitch deviation prediction model is used as the prediction model of model predictive control to adjust the pay-off tension and control the pitch deviation through model predictive control. The wire pairs are combined with filler material to form the cable core. After the cable core is wrapped and fixed, an outer sheath is extruded to form a complete cable.

2. The stranding preparation method of an unshielded data transmission cable as described in claim 1, characterized in that, The tension signal of each wire pair is the average value of the tension of the two wire cores at each acquisition time.

3. The stranding preparation method of an unshielded data transmission cable as described in claim 1, characterized in that, The method of using tension signals as relevant constraints of vibration signals to extract higher-order harmonic components affecting pitch from vibration signals using blind source separation algorithm includes: constructing a mixed signal matrix from vibration signals in all directions and tension signals of all line pairs as input to fast independent component analysis algorithm, and reconstructing the objective function of fast independent component analysis algorithm using the correlation between tension signals and vibration signals to extract higher-order harmonic components from vibration signals.

4. The stranding preparation method of an unshielded data transmission cable as described in claim 3, characterized in that, The higher-order harmonic components include time-domain harmonic components of the second and third harmonics.

5. The stranding preparation method of an unshielded data transmission cable as described in claim 4, characterized in that, The method for constructing the pitch deviation prediction model is as follows: The pitch deviation prediction model for the i-th line pair at time t is: ;in, This represents the predicted pitch deviation value of the i-th line pair at time t. This represents the tension of the i-th wire pair at time t. , Let represent the second and third harmonic components extracted at time t, respectively. , and These represent the preset fitting coefficients.

6. The stranding preparation method of an unshielded data transmission cable as described in claim 1, characterized in that, The analytical method for the standard deviation of the pitch is as follows: ,in, Let n represent the standard deviation of the pitch of all line pairs at time t, and n represent the number of line pairs. This represents the pitch of the i-th line pair at time t-1. This represents the predicted pitch deviation value of the i-th line pair at time t. This represents the average target pitch for all line pairs.

7. The stranding preparation method of an unshielded data transmission cable as described in claim 1, characterized in that, The method for calculating the near-end crosstalk degradation is as follows: ,in, This represents the near-end crosstalk deterioration between adjacent line pairs i and j at time t. Represents the logarithmic function with base 10. , These represent the target pitches of the i-th and j-th line pairs, respectively. , These represent the predicted pitch deviation values ​​for the i-th and j-th line pairs at time t, respectively. This represents the preset coupling coefficient.

8. A method for preparing an unshielded data transmission cable by stranding as described in claim 6 or 7, characterized in that, The target pitch is the preset initial pitch of the corresponding line pair.

9. The stranding preparation method of an unshielded data transmission cable as described in claim 1, characterized in that, The filling material is polypropylene tear cord, and the sheath material is low-density polyethylene.

10. The stranding preparation method of an unshielded data transmission cable as described in claim 1, characterized in that, The wrapping material is selected from polyester tape or non-woven fabric with a thickness of 0.05~0.1mm.

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