A method of stranded construction of a non-shielded data transmission cable

Abstract

The application relates to the technical field of cable stranding preparation, in particular to a stranding preparation method of a non-shielded data transmission cable, which comprises the following steps: pretreating a metal conductor and coating an insulating layer to form an insulating wire core; stranding multiple insulating wire cores into a wire pair, and dynamically adjusting a stranding pitch during the stranding process; combining the wire pair with a filling material to form a cable core, and after the cable core is fixed by being wrapped, extruding an outer layer to coat a sheath, and forming a complete cable. The application aims to dynamically adjust the stranding pitch of the wire pair, dynamically compensate the influence of pitch deviation on crosstalk performance, and realize accurate control of the pitch deviation.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of cable stranding preparation, in particular to a stranding preparation method of a non-shielded data transmission cable. BACKGROUND

[0002] The non-shielded data transmission cable is a cable type widely used in high-speed data transmission scenarios, and the core structure thereof is that a plurality of pairs of mutually insulated copper wires are stranded according to a specific pitch. The non-shielded data transmission cable has no metal shielding layer and has the advantages of low cost, good flexibility and convenient construction. The wires of the non-shielded data transmission cable are usually annealed copper wires, and the thickness of the insulation layer is relatively thin. The non-shielded data transmission cable relies on the differential design of the wire pair stranding pitch to suppress crosstalk generated by electromagnetic coupling between the wire pairs, and the wire pair stranding pitch is a key technical parameter for realizing signal integrity.

[0003] The stranding pitch refers to the distance advanced by a single wire along the stranding axis in one rotation. Since there is no shielding layer for protection, the stranding pitch is more sensitive to pitch deviation. If the pitch deviation is too large, the characteristic impedance will be uneven, which will cause signal reflection and attenuation to form crosstalk, resulting in an increase in the bit error rate and an aggravation of the transmission delay. In the existing patent “CN222145893U A device for controlling pitch deviation of a twisted pair cable”, a speed proximity switch is added to monitor the unwinding speed in real time. The pitch deviation is judged by using the mismatch relationship between the unwinding speed and the stranding arch rotation speed when the pitch is abnormal. The speed and the pitch are indirectly related, and early warning of the pitch abnormality is realized. In the existing patent “CN114660748B Optical cable stranding control method and device, electronic equipment and storage medium”, the intervals in which deviation may exist in the reciprocating stranding are identified, and the stranding pitch compensation amplitude is dynamically adjusted to ensure that the pitch difference in each interval is within a preset range. The segmented compensation strategy is adopted to improve the pitch uniformity.

[0004] However, the existing technology does not consider that the high-order harmonic interference generated by equipment vibration will act on the stranding system through mechanical coupling, so that the actual stranding pitch deviates from the set value, and finally the pitch uniformity problem is formed. Therefore, the technical problem to be solved by the present application is: how to separate the key harmonic components in the equipment vibration in real time during the multi-wire pair stranding process of the non-shielded data cable, dynamically compensate the influence of the wire pair pitch deviation on the crosstalk performance, adjust the unwinding tension, and realize accurate control of the pitch deviation. SUMMARY

[0005] In order to solve the above technical problems, the present application provides a stranding preparation method of a non-shielded data transmission cable to solve the existing problems.

[0006] The stranding preparation method of the non-shielded data transmission cable provided by the present application adopts the following technical scheme:

[0007] One embodiment of the present application provides a stranded preparation method of a non-shielded data transmission cable, which comprises the following steps:

[0008] Pre-treating the metal conductor and coating an insulation layer to form an insulated core;

[0009] Stranding a plurality of insulated cores into wire pairs, and dynamically adjusting the stranding pitch during the stranding process; wherein the dynamic adjustment method is as follows:

[0010] Collecting the tension signals of the wire pairs and the vibration signals of the equipment in all directions in real time during the stranding process of the wire pairs;

[0011] Taking the tension signals as the correlation constraint terms of the vibration signals to extract the high-order harmonic components affecting the pitch from the vibration signals by using a blind source separation algorithm;

[0012] And using the high-order harmonic components and the tension of the wire pairs to construct a pitch deviation prediction model of each wire pair;

[0013] Analyzing the pitch standard deviation of all wire pairs at the current time by using the pitch deviation prediction models of all wire pairs, calculating the near-end crosstalk deterioration amount between adjacent wire pairs at the current time by using the difference between the prediction values of the pitch deviation prediction models of all wire pairs, and taking the weighted sum of the sum of the near-end crosstalk deterioration amounts between all adjacent wire pairs at the current time and the pitch standard deviation as the objective function of model predictive control; taking the pitch deviation prediction model as the prediction model of model predictive control to adjust the wire tension to control the pitch deviation by model predictive control;

[0014] Combining the wire pairs with a filling material to form a cable core, and after the cable core is fixed by being wrapped, extruding an outer jacket to form a complete cable.

[0015] Preferably, the value of the tension signal of each wire pair at each collection time is the average value of the tension of two cores.

[0016] Preferably, the method of taking the tension signals as the correlation constraint terms of the vibration signals to extract the high-order harmonic components affecting the pitch from the vibration signals by using a blind source separation algorithm comprises the following steps: constructing a mixed signal matrix of the vibration signals in all directions and the tension signals of all wire pairs as the input of a fast independent component analysis algorithm, and reconstructing the objective function of the fast independent component analysis algorithm by using the correlation between the tension signals and the vibration signals to extract the high-order harmonic components from the vibration signals.

[0017] Preferably, the high-order harmonic components include 2 times frequency and 3 times frequency time domain harmonic components.

[0018] Preferably, the construction method of the pitch deviation prediction model is as follows: the pitch deviation prediction model of the i-th wire pair at time t is as follows: wherein, denotes the pitch deviation prediction value of the i-th wire pair at time t, denotes the tension of the i-th wire pair at time t, denote the 2nd and 3rd order time domain harmonic components extracted at time t, and denote preset fitting coefficients.

[0019] Preferably, the analysis method of the pitch standard deviation is: wherein, denotes the pitch standard deviation of all wire pairs at time t, and n denotes the number of wire pairs, denotes the pitch of the i-th wire pair at time t-1, denotes the pitch deviation prediction value of the i-th wire pair at time t, denotes the average target pitch of all wire pairs.

[0020] Preferably, the calculation method of the near-end crosstalk deterioration amount is: wherein, denotes the near-end crosstalk deterioration amount between adjacent wire pairs i and j at time t, denotes the logarithm function with base 10, denote the target pitches of the i-th and j-th wire pairs, denote the pitch deviation prediction values of the i-th and j-th wire pairs at time t, denotes a preset coupling coefficient.

[0021] Preferably, the target pitch is a preset initial pitch of the corresponding wire pair.

[0022] Preferably, the filling material is a polypropylene tear rope, and the sheath material is low-density polyethylene.

[0023] Preferably, the wrapping material is a polyester tape or non-woven fabric with a thickness of 0.05-0.1 mm.

[0024] The present application has at least the following beneficial effects:

[0025] The present application improves the target function of FastICA for decomposing the mixed vibration signal based on the correlation between the vibration signal and the tension signal, which can more accurately extract the key harmonic components. Based on the key harmonic components and the tension, each wire pair is modeled, the pitch deviation is calculated, and the tension of the wire pair is adjusted according to the pitch deviation. Based on the pitch deviation and the crosstalk deterioration amount, multi-objective optimization is performed to reduce the correlation between the pitch deviations of the wire pairs and avoid the deterioration of the crosstalk due to the synchronous fluctuation of the pitch. ​​​​BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present application or the prior art, the drawings needed in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0027] Figure 1 A flow chart of a twisting preparation method of a non-shielded data transmission cable provided by the present application;

[0028] Figure 2 A flow chart of a method for dynamically adjusting the twisting pitch in the twisting process provided by the present application. DETAILED DESCRIPTION

[0029] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the specific implementation, structure, features and effects of the twisting preparation method of a non-shielded data transmission cable according to the present application are described in detail as follows by combining the drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0030] 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 the present application belongs.

[0031] The specific scheme of the twisting preparation method of a non-shielded data transmission cable provided by the present application is specifically described below in combination with the drawings.

[0032] One embodiment of the present application provides a twisting preparation method of a non-shielded data transmission cable.

[0033] Specifically, a twisting preparation method of a non-shielded data transmission cable is provided as follows, please refer to Figure 1 The method comprises the following steps:

[0034] The metal conductor is pretreated and coated with an insulating layer to form an insulated wire core;

[0035] A plurality of insulated wire cores are twisted into wire pairs, and the twisting pitch is dynamically adjusted during the twisting process; wherein the method for dynamic adjustment is:

[0036] The tension signals of each wire pair and the vibration signals of the equipment in each direction during the multi-wire pair twisting process are collected in real time;

[0037] The tension signal is taken as a relevant constraint term of the vibration signal to extract the high-order harmonic component affecting the pitch from the vibration signal by using a blind source separation algorithm;

[0038] And a pitch deviation prediction model of each wire pair is constructed by using the high-order harmonic component and the tension of the wire pair;

[0039] The pitch deviation prediction model of all wire pairs is used to analyze the pitch standard deviation of all wire pairs at the current time, and the difference between the predicted values of the pitch deviation prediction models of all wire pairs is used to calculate the near-end crosstalk deterioration between adjacent wire pairs at the current time; and the sum of the near-end crosstalk deterioration between all adjacent wire pairs at the current time and the weighted sum of the pitch standard deviation are taken as the objective function of model predictive control; and the pitch deviation prediction model is taken as the prediction model of model predictive control to adjust the laying tension to control the pitch deviation.

[0040] The wire pairs are combined with the filling material to form a cable core, and after the cable core is fixed by being wrapped, an outer layer is extruded to form a complete cable.

[0041] Embodiment 1

[0042] S1: Pretreating the metal conductor and coating an insulation layer to form an insulated wire core.

[0043] The metal conductor in the present application is a solid copper conductor, and the pretreatment of the metal conductor includes wire drawing, using a wire drawing machine to draw multiple times to a diameter of 0.50 mm±0.01 mm (24 AWG), and then using a continuous annealing process (temperature 350, time 30 s) for annealing.

[0044] An insulated wire core is formed by using a high-speed extruder and a right-angle die for insulation coating, the insulation material is high-density polyethylene (HDPE), the thickness of the insulation material is 0.25 mm±0.02 mm, the barrel temperature is set to 180°C, and the die temperature is set to 210°C.

[0045] S2: Twisting multiple insulated wire cores into wire pairs, and dynamically adjusting the twisting pitch during the twisting process.

[0046] The present application uses a stranding machine to simultaneously twist eight independent insulated wire cores, and two insulated wire cores are twisted into an independent wire pair. The stranding machine has a high speed (1500-3000 RPM), and after a long time of use and wear, the core rotating parts (such as the stranding bow, main shaft, and laying disc) may have a mass eccentricity, so that the centrifugal force generated by the eccentric mass during high-speed operation forms a periodic excitation force with a frequency consistent with the rotational speed. Due to the nonlinearity of the stiffness of the mechanical structure, the excitation force will be distorted during transmission, and high-order components will be derived.

[0047] The high-order harmonic interference can act on the stranding system through mechanical coupling, causing the dynamic balance of the pay-off tension and the rotating speed of the stranding arch to be destroyed. The high-frequency component of the high-order harmonic is prone to resonance with the inherent mode of the stranding equipment, causing instantaneous micro-vibration of components such as the pay-off wheel and the tension sensor, and causing periodic fluctuations in the core tension. For a non-shielded data cable, the core insulation layer is thin and lacks the rigid support of the shielding layer. The tension fluctuations will directly cause the real-time changes in the wire stretching or relaxation amount during the stranding process, so that the actual stranding pitch deviates from the set value, and finally the pitch non-uniformity problem is formed.

[0048] In the embodiment, the four pairs of eight-core structure of the cable are stranded at different pitches, and the pitch difference between the wire pairs is greater than 10%. Through this pitch difference, crosstalk is suppressed. In the embodiment, the target pitches of the four wire pairs are 25 mm, 30 mm, 35 mm and 40 mm. The high-frequency harmonic described above is transmitted through the mechanical structure to affect the pay-off tension of each wire pair, causing the pitch deviation of different wire pairs to present synchronous fluctuations. The pitch fluctuation direction and amplitude of adjacent wire pairs are similar, which will destroy the differentiation of the pitch and cause the crosstalk to deteriorate. The pay-off tension of a single pair of wire cores is in the range of 5-15 N, and the pay-off tension is set to 5 N in the embodiment.

[0049] In the present application, the method flowchart for dynamically adjusting the stranding pitch during the stranding process is shown in the accompanying Figure 2 , and specifically comprises:

[0050] S201: Real-time collection of tension signals of each wire pair and vibration signals of the equipment in each direction during the stranding process.

[0051] A miniature fiber Bragg grating (FBG) tension sensor is used to collect the tension of each wire core during the stranding process. The sensor is vertically installed at the guide wheel at the pay-off end of each pair of wire cores, the sensor axis is consistent with the direction of the wire core tension, the tension of each wire pair is the average value of the tension of the two wire cores, and four tension signals of four wire cores are collected.

[0052] A three-way IEPE acceleration sensor is used to collect the vibration signals of the equipment during the stranding process. Three-way IEPE acceleration sensors (bandwidth 0.5-1000 Hz) are deployed at key positions (main shaft bearing seat, stranding arch support or reducer output shaft) to collect 5 times frequency vibration signals (corresponding to 40-250 Hz frequency band when the data cable stranding speed is 1500-3000 RPM), and three vibration signals in three directions are collected.

[0053] Data collection is triggered at a period of 1 ms to ensure data synchronization. The original vibration signal is filtered by a sliding window (window length 5 ms) to remove power frequency (50 Hz) and switching power supply noise (100 Hz), and a standardized data frame containing a time stamp is output.

[0054] S202: Take the tension signal as a correlation constraint term of the vibration signal to extract a high-order harmonic component affecting the pitch from the vibration signal by using a blind source separation algorithm.

[0055] The natural frequency of the rotating component often coincides with 2-3 times of the fundamental frequency, forming structural resonance. This resonance effect makes the energy of the 2nd and 3rd order frequencies much higher than other harmonics, which becomes the main inducement to destroy the stability of the line pair. In order to avoid the influence of irrelevant components such as environmental noise, the 2nd and 3rd order harmonic signals are first extracted from the original vibration signal.

[0056] Traditional blind source separation algorithms usually only based on the statistical independence assumption of the multi-channel vibration signal itself, decompose the mixed signal into several independent components, and output independent vibration modes that are not correlated with each other, which is difficult to accurately identify the harmonic interference directly related to the pitch deviation. The tension signal directly reflects the stress state of the core during the twisting process, and is the core process parameter of pitch formation. In the present application, the tension signal is taken as a reference anchor, and the correlation between the vibration component and the tension signal is constrained to force the blind source separation algorithm to only retain the vibration mode that is strongly correlated with the tension fluctuation. The specific steps are as follows:

[0057] In this embodiment, the FastICA (Fast Independent Component Analysis) algorithm is used 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 the four wire pairs. The seven rows correspond to the seven dimensions in the mixed signal matrix, and the column dimension is 1s, i.e. 1000 sampling periods. The FastICA algorithm is a known technology.

[0058] The objective function of the traditional FastICA algorithm is the maximum negative entropy. In this application, the tension correlation constraint term is added, and the objective function is wherein represents the negative entropy maximization term, i.e. the objective function of the traditional FastICA algorithm, represents a preset correlation coefficient weight, ranging from 0.6 to 1.5, and the value is 0.8 in this embodiment, and m represents the number of independent components, represents the jth independent component, represents the tension signal of the ith wire pair, () represents the calculation of the Pearson correlation coefficient function.

[0059] In the process of separating the input mixed signal matrix by the FastICA algorithm, the mixed signal matrix is first centralized and whitened to obtain a 7-dimensional whitening matrix; a 7-dimensional orthogonal vector is randomly generated, and is updated by 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.

[0060] Reserve the independent components whose Pearson correlation coefficients with any tension signal are greater than and equal to a preset correlation threshold; in the embodiment, the preset correlation threshold is 0.5, which can be set by the implementer according to the actual situation.

[0061] Perform FFT (Fast Fourier Transform) on each of the reserved independent components to obtain a frequency domain amplitude spectrum and a phase spectrum, extract the amplitudes and phases corresponding to the 2nd and 3rd harmonics (when the rotating speed is 3000 RPM, the fundamental frequency is 50 Hz, and the 2nd and 3rd harmonics are 100 Hz and 150 Hz, respectively); vectorially superimpose the 2nd and 3rd harmonics of all independent components, respectively; perform inverse FFT on the amplitudes and phases of the vectorially superimposed 2nd and 3rd harmonics, respectively, to obtain the time domain harmonic signals of the 2nd and 3rd harmonics, i.e., to obtain the high-order harmonic components affecting the pitch extracted from the vibration signal.

[0062] S203: Establish a pitch deviation prediction model for a single pair of cores, and calculate the pitch compensation amount of each wire pair in combination with the demand for multi-wire pair crosstalk suppression.

[0063] The vibration of the stranding equipment, the inertia difference of the pay-off reel and other factors can cause different wire pairs to bear different harmonic interference intensities and phases, and different wire pairs have different response amplitudes to the same interference source due to different stranding pitch design values, so it is necessary to model different wire pairs respectively.

[0064] Accordingly, a prediction model is constructed for the pitch deviation of each wire pair, and the pitch deviation prediction model of the i-th wire pair at time t is taken as an example: ; wherein represents the pitch deviation prediction value of the i-th wire pair at time t, represents the tension of the i-th wire pair at time t, , represents the time domain harmonic component of the 2nd and 3rd harmonics extracted at time t, respectively, , and represent the preset fitting coefficients, which are obtained by the orthogonal experiment method in the embodiment.

[0065] It should be understood that the tension directly determines the degree of stretching of the core. When the tension changes, the actual length of the wire pair changes, thereby affecting the lay pitch. When the tension increases, the core is stretched, and the pitch may decrease; when the tension decreases, the core shortens, and the pitch may increase. The coefficient determined by data fitting reflects the pitch deviation caused by unit tension change. Equipment vibration will produce 2 times frequency vibration component, and this vibration is transmitted to the wire pair through mechanical coupling, so that the motion state of the wire pair changes periodically, resulting in pitch deviation; the 3 times frequency harmonic is usually derived from the nonlinear characteristics or complex vibration mode of the equipment. It also interferes with the stable lay of the wire pair, and the frequency is higher, and the influence on the high-frequency fluctuation of the pitch is more significant. The coefficient determined by data fitting reflects the relationship between the frequency component and the pitch deviation.

[0066] The effects of tension and vibration harmonics of two key frequencies on pitch deviation are comprehensively considered by linear superposition. The quantitative relationship between pitch deviation and physical influencing factors is established by actual data fitting or experiment, thereby providing a theoretical basis for pitch deviation prediction and control.

[0067] According to the above model for predicting the pitch deviation of the wire pair, only the pitch deviation of one wire pair can be controlled. However, when multiple wire pairs are combined into a cable, the pitch difference between different wire pairs also needs to be considered to achieve the purpose of suppressing crosstalk. The present application performs multi-objective optimization through model predictive control (MPC).

[0068] The objective function in the present application is to minimize the weighted sum of the pitch standard deviation and the total amount of crosstalk deterioration. In the non-shielded data cable laying scene, if only the pitch consistency is pursued, the pitch of adjacent wire pairs may tend to the same value, causing pitch resonance, strong electromagnetic coupling between wire pairs due to similar laying frequencies, and even more severe crosstalk. Non-shielded cables lack a metal shielding layer, and crosstalk between wire pairs mainly relies on differential design of pitch to suppress. If the crosstalk is directly optimized without considering the pitch, the original crosstalk suppression strategy may be damaged.

[0069] The objective function is wherein, represents the objective function of model predictive control at time t, , respectively represent the preset first and second weight coefficients, the value range is 0~1, and in the present embodiment, the values are 0.4 and 0.6 (the weight of crosstalk performance is higher).

[0070] wherein, represents the pitch standard deviation of all wire pairs at time t, and can be represented as:

[0071] , t>1, wherein n represents the number of wire pairs, represents the pitch of the i-th wire pair at time t-1, denotes the pitch deviation prediction value of the i-th wire pair at time t, denotes the average target pitch of all wire pairs. Wherein, the pitch at the initial time is the target pitch of the corresponding wire pair, and the pitch prediction value at the current time is the pitch at the last time plus the pitch deviation prediction value at the current time.

[0072] wherein, denotes the near-end crosstalk degradation amount between adjacent wire pairs i and j at time t, which can be expressed as:

[0073] wherein, denotes the logarithmic function with base 10, , denote the target pitch of the i-th and j-th wire pair, respectively, , denote the pitch deviation prediction value of the i-th and j-th wire pair at time t, respectively, denotes a preset coupling coefficient, which is inversely proportional to the physical distance between the wire pairs, and the value range is 0.8~0.9. In the embodiment, when the physical distance between the i-th and j-th wire pairs is 0.5 cm, the value is 0.85.

[0074] It should be understood that the pitch deviation of adjacent wire pairs will destroy the periodicity of the stranded structure, resulting in an increase in the length of the parallel section between the wire pairs, and further exacerbating electromagnetic coupling. The destruction of uniformity caused by the pitch deviation is quantified by the ratio of the difference between the pitch deviation and the target pitch, and a coupling coefficient inversely proportional to the physical distance between the wire pairs is introduced. The linear coupling degradation amount is converted into the near-end crosstalk degradation amount in decibels commonly used in the communication field through logarithmic transformation, thereby establishing a direct quantitative relationship between the pitch deviation and the crosstalk degradation.

[0075] The present application adjusts the wire laying tension through model predictive control (MPC) to control the pitch deviation, and the adjustment range of the wire laying tension is constrained to be about -1N~1N. The prediction model of the MPC in the present application is a state transition equation, i.e. a pitch deviation prediction model, and the optimization target is a target function , and the constraint condition is the adjustment range of the wire laying tension. The specific solving steps are as follows:

[0076] The tension and vibration signals of each wire pair are collected in real time, and the harmonic components are extracted; the pitch deviation of the next two periods is recursively calculated using the state transition equation; based on the predicted future deviation, the optimal control sequence (QP solver) is solved through quadratic programming (QP), i.e. the adjustment amount of the wire laying tension, so that the target function is minimized while meeting the constraint condition; the control amount at the current time is executed, and the above process is repeated in the next period, i.e. the model is updated using the new measurement value and re-optimized.

[0077] S3: combine the wire pairs with the filling material to form a cable core, after the cable core is fixed by being wrapped, an outer layer is extruded to form a complete cable.

[0078] The filling material is a polypropylene tear rope, and a polyester tape (PET) or non-woven fabric with a thickness of 0.05-0.1 mm is selected for wrapping. In this embodiment, a polyester tape with a thickness of 0.05 mm is selected for wrapping. The sheath material is low-density polyethylene (LDPE), which is also extruded by an extruder. Finally, the cable model, manufacturer name, and execution standard are printed to form a complete cable.

[0079] Example 2

[0080] In step S1 of this embodiment, the temperature of the continuous annealing process is 375°C, and the annealing time is 45 s. The barrel temperature is set to 170°C, and the die temperature is set to 200°C. The other aspects are the same as in Example 1.

[0081] In step S2 of this embodiment, the wire laying tension is set to 10 N. The other aspects are the same as in Example 1.

[0082] In step S3 of this embodiment, a polyester tape with a thickness of 0.07 mm is selected for wrapping. The other aspects are the same as in Example 1.

[0083] Example 3

[0084] In step S1 of this embodiment, the temperature of the continuous annealing process is 400°C, and the annealing time is 60 s. The barrel temperature is set to 160°C, and the die temperature is set to 190°C. The other aspects are the same as in Example 1.

[0085] In step S2 of this embodiment, the wire laying tension is set to 15 N. The other aspects are the same as in Example 1.

[0086] In step S3 of this embodiment, a polyester tape with a thickness of 0.1 mm is selected for wrapping. The other aspects are the same as in Example 1.

[0087] To verify the effectiveness of the present application, a plurality of comparative examples are set, specifically:

[0088] Example 1: the wire laying tension is set to 5 N, and the tension is dynamically adjusted during the twisting process;

[0089] Example 2: the wire laying tension is set to 10 N, and the tension is dynamically adjusted during the twisting process;

[0090] Example 3: the wire laying tension is set to 15 N, and the tension is dynamically adjusted during the twisting process;

[0091] Comparative Example 1: The wire laying tension is set to 5N and is not adjusted during the twisting process.

[0092] Comparative Example 2: The wire laying tension is set to 10N and is not adjusted during the twisting process.

[0093] Comparative Example 3: The wire laying tension is set to 15N and is not adjusted during the twisting process.

[0094] Except for the description, the process flow and parameters of Comparative Examples 1, 2, and 3 correspond to Examples 1, 2, and 3, respectively.

[0095] The fixed tension is compared with the present application as shown in the following table:

[0096] Table 1: Comparison of wire laying tension

[0097]

[0098] From Table 1, it can be seen that Examples 1-3 have significantly reduced pitch deviation, higher near-end crosstalk (NEXT) value, smaller characteristic impedance fluctuation, and significantly reduced insulation damage rate compared to the corresponding comparative examples. The reason is that dynamic adjustment extracts high-order harmonic components in equipment vibration through blind source separation algorithm, combines pitch deviation prediction model and multi-objective optimization to dynamically adjust the wire laying tension, offsets the tension fluctuation caused by vibration, accurately controls the pitch differentiation, avoids excessive stretching or relaxation of the wire core, thereby improving the pitch uniformity, crosstalk suppression capability, and insulation reliability.

[0099] The above technical features constitute the best embodiment of the present application, which has strong adaptability and best implementation effect. Non-essential technical features can be added or removed according to actual needs to meet different situation requirements.

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, a sheath is extruded on the outer layer to form a complete cable. 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. The higher-order harmonic components include time-domain harmonic components of the second and third harmonics. 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.

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 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.

4. 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.

5. A method for preparing an unshielded data transmission cable by stranding as described in claim 3 or 4, characterized in that, The target pitch is the preset initial pitch of the corresponding line pair.

6. 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.

7. 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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