Environment-friendly nylon cable coating method

Abstract

The invention relates to the technical field of cable coatings, in particular to an environment-friendly nylon cable coating method. According to the method, the attenuation condition of vibration data of different positions on a cable along with the distance is analyzed, vibration source possibilities of different positions are obtained, the state influence degree of different positions on vibration components is determined by combining the direction of vibration signals at an inlet of an extruder and vibration fluctuation of component signals, and the state influence degree serves as measurement to participate in vibration signal prediction. Obtaining a prediction signal; the cable vibration state is obtained by predicting the vibration condition in the signal, the cooperative relation is analyzed by combining the heating temperature of the extruder, a cooperative influence value is determined, and a correction value is obtained by combining the thickness change of the cable to regulate and control the heating temperature. According to the method, the signal prediction accuracy is improved by analyzing the multi-position vibration state in the coating process, the condition that the predicted vibration state and the heating temperature are affected by historical cooperation is considered, the temperature feedback condition is adjusted, temperature adjustment is more suitable, and the quality of the cable coating process is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of cable coatings, and particularly to an environment-friendly nylon cable coating method. Background Art

[0002] The main component of nylon cables is nylon material, which is widely used in the field of electrical engineering and is favored for its unique properties and various advantages. Due to its high voltage resistance, corrosion resistance, and excellent mechanical strength, nylon cables are widely used in fields such as power engineering, transportation, aerospace, and industrial manufacturing.

[0003] The vibration characteristics generated at different times and by different vibration sources are different. Since the extruder usually applies pressure to the nylon material in the vertical direction and makes it adhere to the cable, if the vibration amplitude of the cable in the vertical direction is large at this time, it will cause fluctuations in the extrusion pressure, resulting in periodic thickness changes in the coating, that is, the "bamboo joint" phenomenon. After the conductor core is stranded to form a cable composed of multiple cores, the outer contour of the cable itself is no longer regular. At this time, if the nylon is at a relatively low temperature within the melting range, it will cause uneven local thickness or stripes in the cable coating; if the temperature in the extruder is increased, the high temperature will cause nylon thermal degradation, resulting in embrittlement of the coating and a decrease in adhesion after cooling. Therefore, when the adjustment of the heating temperature during production is inappropriate, it will affect the cable coating process and lead to a decrease in the quality of the coated cable. Summary of the Invention

[0004] In order to solve the technical problem that when the adjustment of the heating temperature during production is inappropriate in the prior art, it will affect the cable coating process and lead to a decrease in the quality of the coated cable, the purpose of the present invention is to provide an environment-friendly nylon cable coating method, and the specific technical solution adopted is as follows:

[0005] The present invention provides an environment-friendly nylon cable coating method, and the method includes:

[0006] At each acquisition position on the cable support in front of the extruder and at the entrance of the extruder, obtain the vibration signal and the heating temperature in the sampling time series; decompose the vibration signal at the entrance of the extruder into vibration component signals;

[0007] At each sampling position, according to the approximation between the vibration signal and each vibration component signal in terms of frequency, and by analyzing the attenuation law of the amplitude of the vibration signal with distance between the sampling position and other sampling positions, obtain the possible index of the vibration source at each sampling position;

[0008] According to the deviation of the direction of the vibration signal at the inlet of the extruder from the vertical direction, and the amplitude-frequency ratio of each vibration component signal, combined with the possible index size distribution of the vibration source at each sampling position, determine the vibration influence degree of each sampling position on each vibration component signal;

[0009] Taking the vibration influence degree of each sampling position on each vibration component signal as a measure, perform signal prediction and integration on each vibration component signal to obtain the predicted vibration signal at the inlet of the extruder; determine the cable vibration state index of the predicted vibration signal through the direction and amplitude-frequency ratio of the predicted vibration signal;

[0010] Analyze the synergy relationship between the vibration state of the vibration signal at the inlet of the extruder and the heating temperature in the historical sampling time series, combine the heating temperature and the cable vibration state index at the current moment to obtain the synergy influence value at the current moment;

[0011] Determine the correction value at the current moment through the change in the coating thickness at the outlet of the extruder and the synergy influence value in the sampling time series; adjust the heating temperature of the coating at the current moment based on the correction value.

[0012] Further, the method for obtaining the possible index of the vibration source includes:

[0013] For any sampling position, calculate the difference between the frequency of the vibration signal at this sampling position and the frequencies of each vibration component signal as the frequency difference degree; perform a negative correlation mapping on the minimum value of all frequency difference degrees as the analysis authenticity of this sampling position;

[0014] Arrange the sampling positions on the cable support in front of the extruder in order to obtain a position sequence; in the position sequence, calculate the amplitude difference between each sampling position except the first sampling position and the previous sampling position to obtain the amplitude deviation degree of each sampling position;

[0015] Based on the amplitude deviation degree, analyze the amplitude change characteristics of this sampling position before and after the position sequence to obtain the vibration source characteristic index of this sampling position;

[0016] Combine the analysis authenticity and the vibration source characteristic index of this sampling position to obtain the possible index of the vibration source at this sampling position.

[0017] Further, the method for obtaining the vibration source characteristic index includes:

[0018] Before this sampling position in the position sequence, calculate the ratio of the sum value of the amplitude deviation degrees of all sampling positions to the sum value of the absolute values of the amplitude deviation degrees of all sampling positions to obtain the pre-vibration change characteristic index of this sampling position;

[0019] After the sampling position in the position sequence, the sum value of the amplitude deviation degrees of all sampling positions is compared with the sum value of the absolute values of the amplitude deviation degrees of all sampling positions to obtain the post-vibration change characteristic index of this sampling position;

[0020] Normalize the difference between the post-vibration change characteristic index and the pre-vibration change characteristic index of this sampling position to obtain the vibration source characteristic index of this sampling position.

[0021] Further, the method for obtaining the vibration influence degree includes:

[0022] Perform vector decomposition on the vibration signal at the inlet of the extruder to obtain the vibration direction; normalize the included angle between the vibration direction and the vertical direction to obtain the extrusion direction influence degree;

[0023] For any one vibration component, calculate the ratio of the amplitude to the frequency of the vibration component signal to obtain the vibration amplitude influence degree of this vibration component;

[0024] Take the distance between the sampling position with the largest possible vibration source index and the inlet position of the extruder as the distance influence degree; for any one sampling position, take the ratio of the possible vibration source index of this sampling position to the distance influence degree as the vibration source influence degree of this sampling position;

[0025] Combine the extrusion direction influence degree, the vibration amplitude influence degree of this vibration component, and the vibration source influence degree of this sampling position to obtain the vibration influence degree of this sampling position on this vibration component.

[0026] Further, the method for obtaining the predicted vibration signal includes:

[0027] For any one vibration component, use the vibration signal of each sampling position in the sampling time sequence as an externally introduced variable, and perform autoregressive integrated moving average prediction on this vibration component to obtain the predicted signal affected at each sampling position of this vibration component;

[0028] Take the vibration influence degree of each sampling position on the vibration component signal as the weight, and perform weighted averaging on the predicted signals affected at each sampling position of this vibration component to obtain the predicted signal mean value of this vibration component;

[0029] Based on the EMD algorithm, integrate the predicted signal means of all vibration components to obtain the predicted vibration signal.

[0030] Further, the method for obtaining the cable vibration state index includes:

[0031] Perform vector decomposition on the predicted vibration signal to obtain the vibration direction of the predicted vibration signal; normalize the included angle between the vibration direction of the predicted vibration signal and the vertical direction to obtain the direction influence index of the predicted vibration signal;

[0032] Use the product of the ratio of the amplitude to the frequency of the predicted vibration signal and the direction influence index as the cable vibration state index of the predicted vibration signal.

[0033] Furthermore, the method for obtaining the collaborative influence value includes:

[0034] Normalize the heating temperature at the current moment to obtain the temperature index at the current moment;

[0035] Obtain the motion state at each moment in the sampling time series; map all moments in the sampling time series to a two-dimensional collaborative coordinate system according to the motion state and heating temperature at each moment; the horizontal axis of the two-dimensional collaborative coordinate system is the motion state, and the vertical axis is the heating temperature;

[0036] Use the PCA algorithm for the data points in the two-dimensional collaborative coordinate system to obtain the principal component direction; normalize the angle between the principal component direction and the horizontal axis of the coordinate to obtain the temperature collaborative coefficient;

[0037] Use the product of the temperature collaborative coefficient and the temperature index as the temperature influence value; use the product of the value obtained by negatively correlating the temperature collaborative coefficient and the cable vibration state index as the vibration influence value; use the sum of the temperature influence value and the vibration influence value as the collaborative influence value at the current moment.

[0038] Furthermore, the method for obtaining the correction value includes:

[0039] Obtain the coating thickness at the outlet of the extruder in the sampling time series; after calculating the difference between the coating thickness at the current moment and the coating thickness at each moment in the sampling time series, calculate the average value of all differences and normalize it to obtain the thickness non-uniformity at the current moment;

[0040] Use the ratio of the thickness non-uniformity to the normalized collaborative influence value as the correction value at the current moment.

[0041] Furthermore, the regulation of the heating temperature coated at the current moment based on the correction value includes:

[0042] Use the product of the correction value at the current moment and the heating temperature as the adjusted heating temperature; regulate the heating temperature at the next moment to the adjusted heating temperature.

[0043] Furthermore, the method for obtaining the vibration component signal includes:

[0044] Use the EMD decomposition algorithm for the vibration signal at the inlet of the extruder to obtain each IMF component as the vibration component signal.

[0045] The present invention has the following beneficial effects:

[0046] By analyzing the attenuation of vibration data at different positions on the cable with respect to distance, considering the variation characteristics of vibration data at the actual vibration source position, the possibilities of vibration sources at different positions are obtained. Meanwhile, based on the main direction of the amplitude of the vibration signal at the extruder inlet and the amplitude frequency fluctuations of the vibration component signals, the influence degree of different positions on the state of each vibration component is determined, reflecting the influence of the cable movement state at the extruder inlet analyzed at each sampling position on the nylon coating effect. Using the influence degree as a metric to participate in the prediction of the vibration signal at the extruder inlet, a predicted signal is obtained, avoiding the error situation that occurs when directly predicting based on the vibration data monitored by the sensors at the extruder inlet and performing feedback adjustment on the extruder, and improving the accuracy of subsequent feedback adjustment. By judging the cable vibration state within a continuous historical time period based on the predicted vibration data, analyzing the different degrees of influence of the extruder heating temperature and the vibration state on the coating process, the combined influence value at the current moment is obtained by combining the current cable vibration state and the extruder heating temperature. Based on the relationship between the actually measured cable thickness and the combined influence, feedback adjustment analysis is carried out to obtain a correction value for pre-regulating the heating temperature at a future moment, improving the timeliness and efficiency of temperature adjustment and ensuring the high quality of the cable coating process. The present invention improves the signal prediction accuracy by analyzing the vibration states at multiple positions during the coating process, and considering the historical combined influence of the predicted vibration state and the heating temperature, adjusts the temperature feedback situation to make the temperature adjustment more appropriate and ensure the quality of the cable coating process. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0048] Figure 1 It is a flowchart of an environmentally friendly nylon cable coating method provided by an embodiment of the present invention;

[0049] Figure 2 It is a schematic diagram of the decomposition of a vibration signal provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0050] To further elaborate on the technical means and effects adopted by the present invention to achieve the intended invention purpose, the following specifically describes, in conjunction with the accompanying drawings and preferred embodiments, a method for coating an environmentally friendly nylon cable, including its specific implementation manner, structure, features, and effects. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs.

[0052] The following specifically describes the specific solution of a method for coating an environmentally friendly nylon cable provided by the present invention in conjunction with the accompanying drawings.

[0053] The core of a low-voltage communication cable is usually composed of multiple strands of copper wire. Low-voltage cables come in several types, such as single-core, double-core, triple-core, and four-core. Double-core cables are used for single-phase circuits, triple-core and four-core cables are used for three-phase three-wire and three-phase four-wire circuits respectively, and single-core cables can be applied to single-phase or three-phase circuits as needed.

[0054] The first manufacturing process of the conductor is wire drawing. In this process, the wire is stretched and extended, gradually reducing the diameter of the single wire to the final target core cross-sectional area. Usually, the area size ranges from 10mm 2 to 240mm 2 . In the final stage of wire drawing, all wires need to undergo "annealing" heat treatment to enhance the ductility and conductivity of copper. The second manufacturing process of the conductor is wiring (stranding). Multiple single wires (such as copper wires and aluminum wires) are stranded into a conductor core by a frame strander to increase the cross-sectional area and conductivity of the cable while maintaining flexibility.

[0055] After the conductor material is pretreated, nylon material can be coated. Since nylon particles have strong hygroscopicity, they need to be dried before coating. In the embodiment of the present invention, the cable after wiring is preheated using an infrared device to increase its surface temperature and enhance the adhesion between nylon and the cable. The nylon is heated in an extruder, and the temperature of the heating section of the extruder is adjusted according to the type of nylon. For example, for PA6: 220 - 260 °C, for PA12: 180 - 220 °C, thus melting the nylon material for subsequent extrusion and coating.

[0056] By adjusting the screw speed to match the cable traction speed, ensure uniform extrusion of the nylon melt. A special coating die, such as a pressure die head, is used to control the coating layer thickness, usually controlled within 0.1 - 0.5mm.

[0057] Since the production process of cables is usually continuous, that is, the relevant production equipment for cable stretching, wiring, and coating are arranged in sequence. At this time, for each cable, it will move on various production equipment and complete various processes, and several guide wheel brackets are installed in the moving direction of the cable. The entire production process depends on the stable operation of the transmission components. Affected by multiple production equipment, the cable will vibrate during the continuous process of completing various processes, resulting in uneven thickness of the cable coating in different local areas.

[0058] Therefore, to provide a higher-quality cable coating process, please refer to Figure 1 , which shows a flowchart of an environmentally friendly nylon cable coating method provided by an embodiment of the present invention. The method includes the following steps:

[0059] S1: At each acquisition position on the cable support in front of the extruder and at the entrance of the extruder, obtain the vibration signal and heating temperature in the sampling time series; decompose the vibration signal at the entrance of the extruder into vibration component signals.

[0060] During the coating process, the thickness state of the nylon material of the cable depends on the overall vibration amplitude of the cable and the ratio of the extrusion speed of the nylon material by the extruder to the cable traction speed. Therefore, the vibration state of the cable will affect the coating thickness. To ensure the reliability of vibration analysis, in the embodiment of the present invention, sensors are installed on each guide wheel bracket on the cable before the entrance of the extruder and at the entrance of the extruder to monitor the vibration state of the cable before the coating process.

[0061] The position of each sensor is also the sampling position. The vibration data and heating temperature at each moment in the sampling time series are collected through the sensor. The sampling time series is set as the time series within the past 1 minute. The specific values can be adjusted by the implementer and are not limited here.

[0062] The vibration situation at the entrance of the extruder is the main factor affecting the vibration state of the processing process. Considering the complex process environment and the superposition effect of various vibrations, through signal decomposition, the vibration data at different frequencies are analyzed. In the embodiment of the present invention, the vibration signal at the entrance of the extruder is decomposed using the EMD decomposition algorithm to obtain each IMF component as the vibration component signal. It should be noted that signal decomposition is a well-known technical means for those skilled in the art and will not be elaborated here. Please refer to Figure 2 , which shows a schematic diagram of vibration signal decomposition provided by an embodiment of the present invention.

[0063] S2: At each sampling position, according to the approximation between the vibration signal and each vibration component signal in terms of frequency, and analyzing the attenuation law of the amplitude of the vibration signal between the sampling position and other sampling positions with distance, obtain the possible vibration source indicators for each sampling position.

[0064] Since the process equipment on the production line is in the working process together, it will generate a variety of different vibration source signals that are superimposed on each other. Since vibration needs to pass through several process equipment and brackets during the transmission through the cable, there is a certain attenuation of the vibration. When the vibration source changes, the positions of the process equipment it passes through do not change. Therefore, the attenuation of the vibration can be regarded as approximately linear attenuation. At this time, for all the installed sensors, there are certain differences in the vibration data monitored by them. Directly predicting the monitored vibration data at the inlet of the extruder is likely to have errors.

[0065] For the inlet of the extruder, the closer to the vibration source, the greater the amplitude of the vibration signal generated by the vibration source, and the amplitude gradually decreases as the distance increases. Therefore, the possible vibration source analysis is carried out by sampling positions that satisfy the law of amplitude attenuation from large to small with distance, and considering the proximity of the frequency affected by the vibration source at the inlet of the extruder, which reflects the credibility of the sampling position as the vibration source with influence.

[0066] Preferably, in the embodiment of the present invention, the method for obtaining the possible index of the vibration source at the sampling position includes:

[0067] First, for any sampling position, calculate the difference between the frequency of the vibration signal at this sampling position and the frequency of each vibration component signal as the frequency difference degree. Map the minimum value of all frequency difference degrees negatively, as the analysis authenticity of this sampling position. Reflect the influence of the sampling position on the inlet position signal through the frequency deviation situation. When the frequency difference degree is smaller, it indicates that there is more likely a situation where the frequency of the sampling position is consistent with the component signal. At this time, the credibility of the sampling position analysis having the characteristics of the vibration source is higher.

[0068] It should be noted that negative correlation mapping is a well-known technical means for those skilled in the art, such as in the form of inverse proportion or negative exponential power, etc., and is not limited here.

[0069] Further analyze the attenuation characteristics of the amplitude. First, arrange the sampling positions on the cable bracket in front of the extruder in order to obtain a position sequence. In the position sequence, calculate the amplitude difference of the vibration signal between each sampling position except the first sampling position and the previous sampling position to obtain the amplitude deviation degree of each sampling position. That is, always take the left position as the minuend in the position sequence for subsequent analysis of the increase amplitude change.

[0070] It can be understood that there is no previous sampling position for the first sampling position. Therefore, in the embodiment of the present invention, the first sampling position does not participate in the change analysis. In other embodiments of the present invention, the amplitude deviation degree of the first sampling position can be set as the amplitude deviation degree of the subsequent sampling position.

[0071] Furthermore, based on the amplitude deviation degree, analyze the amplitude change characteristics before the sampling position in the position sequence and the amplitude change characteristics after the sampling position in the position sequence, and obtain the vibration source characteristic index of the sampling position. When the amplitude decreases with the increase of distance when moving forward or backward from the sampling position, the sampling position is more likely to be the vibration source.

[0072] In the embodiment of the present invention, the method for obtaining the vibration source characteristic index includes:

[0073] Before the sampling position in the position sequence, compare the sum value of the amplitude deviation degrees of all sampling positions with the sum value of the absolute values of the amplitude deviation degrees of all sampling positions to obtain the pre-vibration change characteristic index of the sampling position, and judge the attenuation of the amplitude change with the distance change through the cumulative value of the amplitude difference and the cumulative value of the absolute value of the amplitude difference.

[0074] As an example, the expression of the pre-vibration change characteristic index is: In the formula, h i represents the pre-vibration change characteristic index of the i-th sampling position, NL represents the total number of sampling positions before this sampling position, and ΔAL x represents the amplitude deviation degree of the x-th sampling position before this sampling position. The value range of the pre-vibration change characteristic index is between [-1, 1]. The closer the pre-vibration change characteristic index is to -1, the more obvious the amplitude change increases with the distance change.

[0075] Similarly, after the sampling position in the position sequence, compare the sum value of the amplitude deviation degrees of all sampling positions with the sum value of the absolute values of the amplitude deviation degrees of all sampling positions to obtain the post-vibration change characteristic index of the sampling position. At this time, the closer the post-vibration change characteristic index is to 1, the more obvious the amplitude change decreases with the distance change.

[0076] Therefore, normalize the difference between the post-vibration change characteristic index and the pre-vibration change characteristic index of the sampling position to obtain the vibration source characteristic index of the sampling position. The larger the vibration source characteristic index, the more significant the characteristic that the sampling position decreases from large to small with the distance on both sides.

[0077] Finally, combine the analysis authenticity of the sampling position with the vibration source characteristic index to obtain the vibration source possibility index of the sampling position. In the embodiment of the present invention, the product of the analysis authenticity and the vibration source characteristic index is used as the vibration source possibility index of the sampling position. The larger the vibration source possibility index, the higher the possibility that the sampling position is the vibration source.

[0078] S3: Determine the vibration influence degree of each sampling position on each vibration component signal based on the deviation between the direction of the vibration signal at the extruder inlet and the vertical direction, the amplitude-frequency ratio of each vibration component signal, and the possible index size distribution of the vibration source at each sampling position.

[0079] Since the vibration characteristics generated by different vibration sources at different times are different, that is, for any vibration, the amplitude, frequency, and direction generated are different. Among them, the extruder usually applies pressure to the nylon material in the vertical direction and makes it adhere to the cable. And if the vibration amplitude of the cable in the vertical direction is large, it will cause fluctuations in the extrusion pressure, resulting in periodic thickness changes in the coating. Therefore, the vibration influence can be analyzed from both the direction angle and the amplitude frequency.

[0080] At the same time, the greater the distance between the vibration source and the extruder inlet, the smaller the impact on the actual coating process. Therefore, further combine the possible index distribution of the vibration source at the sampling position to comprehensively analyze the vibration influence degree on the vibration component signal from three aspects.

[0081] Preferably, in the embodiment of the present invention, the method for obtaining the vibration influence degree includes:

[0082] The extruder applies pressure in the vertical direction to coat the melted nylon on the cable. If the vibration amplitude of the cable in the vertical direction is large, it will cause fluctuations in the extrusion pressure, forming a "bamboo joint" phenomenon. Therefore, first decompose the vibration signal at the extruder inlet vectorially to obtain the vibration direction, normalize the angle between the vibration direction and the vertical direction to obtain the extrusion direction influence degree. When the angle approaches 0°, the vibration direction is the same as the extrusion pressure direction, directly affecting the coating thickness. When the angle approaches 90°, the vibration direction is perpendicular to the extrusion pressure direction, with less influence.

[0083] Furthermore, for any vibration component, calculate the ratio of the amplitude to the frequency of the vibration component signal to obtain the vibration amplitude influence degree of the vibration component. Low-frequency large-amplitude vibration will cause slow but large thickness fluctuations, easily forming "bamboo joints", while high-frequency small-amplitude vibration may be quickly offset by the equipment, with less influence. Through the ratio, comprehensively quantify the "threat level" of the vibration. When the vibration amplitude influence degree is larger, it reflects that it is more likely to be low-frequency large-amplitude vibration, with a significant impact on coating. When the vibration amplitude influence degree is smaller, it reflects that it is more likely to be high-frequency small-amplitude vibration, with less influence.

[0084] Furthermore, the distance between the sampling position with the largest possible index of the vibration source and the inlet position of the extruder is taken as the distance influence degree. The closer the distance is, the greater the influence is. Further, considering the influence of the magnitude of the possible index of the specific vibration source, for any sampling position, the ratio of the possible index of the vibration source at this sampling position to the distance influence degree is taken as the influence degree of the vibration source at this sampling position. When the possible index of the vibration source is larger and the distance is smaller, it reflects that the influence on the inlet is more significant.

[0085] Finally, by combining the extrusion direction influence degree, the vibration amplitude influence degree of this vibration component, and the influence degree of the vibration source at this sampling position, the vibration influence degree of this sampling position on this vibration component is obtained. In the embodiment of the present invention, the product of the extrusion direction influence degree, the vibration amplitude influence degree of this vibration component, and the influence degree of the vibration source at this sampling position is normalized to obtain the vibration influence degree of this sampling position on this vibration component.

[0086] When the vibration influence degree is larger, it reflects that the sampling position has a more significant influence on the vibration state of this vibration component signal in terms of the nylon coating effect. It should be noted that normalization is a well-known technical means to those skilled in the art. The choice of normalization can be linear normalization or standard normalization, etc. The specific normalization method is not limited here.

[0087] S4: Using the vibration influence degree of each sampling position on each vibration component signal as a metric, signal prediction and integration are performed on each vibration component signal to obtain the predicted vibration signal at the inlet of the extruder; through the direction and amplitude frequency ratio of the predicted vibration signal, the cable vibration state index of the predicted vibration signal is determined.

[0088] When the vibration signal at the sampling position does have an impact on the component signal, introducing the vibration signal as an exogenous variable can help the prediction model better understand and capture this impact relationship, thereby improving the accuracy of prediction. Therefore, at this time, the vibration influence degree of each sampling position on each vibration component signal can be used as a metric, and based on the fact that the component signal at the current inlet of the extruder is affected by the signals at the corresponding other sensor positions, the prediction analysis process is adjusted.

[0089] Preferably, in the embodiment of the present invention, the method for obtaining the predicted vibration signal includes:

[0090] First, for any one vibration component, the vibration signals of each sampling position in the sampling time series are used as externally introduced variables, and autoregressive integrated moving average is used to predict this vibration component to obtain the predicted signals affected by this vibration component at each sampling position, and preliminary prediction is performed through the influence of the vibration signal at a single position. It should be noted that model prediction is a well-known technical means to those skilled in the art. In other embodiments of the present invention, a multiple regression model can also be used for prediction, which will not be elaborated and limited here.

[0091] Further, the vibration influence degree of each sampling position on the vibration component signal is used as a weight, and the predicted signals affected by the vibration component at each sampling position are weighted and averaged to obtain the mean value of the predicted signal of the vibration component. By combining the influences of all sampling positions with the vibration influence degree as the weight, the predicted result adjusted by the overall sampling position on the vibration component is obtained.

[0092] Combining the prediction situations of all vibration component signals, based on the EMD algorithm, the mean values of the predicted signals of all vibration components are integrated to obtain the predicted vibration signal, and the adjusted predicted vibration signal is obtained through component integration.

[0093] The vibration characteristics on the predicted vibration signal, that is, the deviation between the vibration direction and the vertical angle, and the ratio of the amplitude frequency, are used to reflect the vibration state of the signal in the prediction situation. In the embodiment of the present invention, the method for obtaining the cable vibration state index includes:

[0094] First, the predicted vibration signal is vectorially decomposed to obtain the vibration direction of the predicted vibration signal, and the angle between the vibration direction of the predicted vibration signal and the vertical direction is normalized to obtain the direction influence index of the predicted vibration signal. Furthermore, the product of the ratio of the amplitude to the frequency of the predicted vibration signal and the direction influence index is used as the cable vibration state index of the predicted vibration signal.

[0095] The direct interference of the vibration direction on the extrusion pressure is quantified by the angle situation. The intensity and persistence of the vibration are comprehensively evaluated by the amplitude frequency ratio. The combination of the two can accurately identify the vibration mode that poses the greatest threat to the coating quality and provide a basis for subsequent dynamic regulation.

[0096] S5: Analyze the synergistic relationship between the vibration state of the vibration signal at the inlet of the extruder and the heating temperature in the historical sampling time series, and combine the heating temperature and the cable vibration state index at the current moment to obtain the synergistic influence value at the current moment.

[0097] The working principle of the extruder is to extrude and coat the melted nylon material on the cable. At this time, the heating temperature of the nylon by the extruder and the movement state of the cable jointly determine the final adhesion effect of the nylon material. Since the conductor core is stranded to form a cable composed of multiple cores, the outer contour of the cable itself is no longer regular. At this time, if the nylon is at a relatively low temperature within the melting range, it will cause uneven local thickness or stripes of the cable coating. If the temperature in the extruder is relatively high, the high temperature will cause nylon thermal degradation, resulting in brittle coating and decreased adhesion after cooling.

[0098] Therefore, based on the changes in the vibration state and heating temperature over historical time series, the influence between the current heating temperature and the predicted signal situation in the collaborative relationship can be analyzed, so as to judge the combined influence of the cable vibration state and the extruder heating temperature on the coating state, and at the same time avoid the error in the subsequent feedback control process caused by the superposition of two different influencing factors.

[0099] Preferably, in the embodiment of the present invention, the method for obtaining the collaborative influence value includes:

[0100] First, normalize the heating temperature at the current moment to obtain the temperature index at the current moment. In the embodiment of the present invention, normalization can be performed within the melting temperature range of the corresponding nylon material to obtain the actual heating temperature situation.

[0101] Furthermore, obtain the motion state at each moment in the sampling time series. In the embodiment of the present invention, the process of obtaining the motion state and the cable vibration state index is the same. Decompose the vibration signal at each moment into vectors, obtain the vibration direction and calculate the angle with the vertical direction for normalization to obtain the angle state index; multiply the ratio of the amplitude to the frequency of the vibration signal at each moment by the angle state index as the motion state at each moment.

[0102] Further, according to the motion state and heating temperature at each moment, map all moments in the sampling time series to a two-dimensional collaborative coordinate system. The horizontal axis of the two-dimensional collaborative coordinate system is the motion state, and the vertical axis is the heating temperature. Analyze the collaborative relationship through the spatial distribution characteristics of the data points in the coordinate system.

[0103] Apply the PCA algorithm to the data points in the two-dimensional collaborative coordinate system to obtain the principal component direction. Normalize the angle between the principal component direction and the horizontal axis of the coordinate to obtain the temperature collaborative coefficient. Normalize the angle between the principal component direction and the horizontal axis of the coordinate from [0, 90°] to [0, 1]. When the temperature collaborative coefficient is higher than 0.5 and the larger it is, it indicates that the heating temperature has a greater influence on the coating effect. On the contrary, when the temperature collaborative coefficient is less than or equal to 0.5 and the smaller it is, it indicates that the motion state has a greater influence on the coating effect.

[0104] It should be noted that both the coordinate system mapping and the PCA algorithm are well-known technical means to those skilled in the art and will not be elaborated here.

[0105] Finally, multiply the temperature collaborative coefficient by the temperature index as the temperature influence value, and multiply the value obtained by negatively correlating the temperature collaborative coefficient by the cable vibration state index as the vibration influence value. Perform weighted summation with the temperature collaborative coefficient to comprehensively reflect the collaborative influence, and use the sum of the temperature influence value and the vibration influence value as the collaborative influence value at the current moment.

[0106] As an example, the expression for the collaborative influence value is: f = k × T + (1 - k) × H; where f represents the collaborative influence value, k represents the temperature collaboration coefficient, T represents the temperature index, H represents the cable vibration state index, k × T represents the temperature influence value, and (1 - k) × H represents the vibration influence value.

[0107] S6: Determine the correction value at the current moment by sampling the coating thickness change and the collaborative influence value at the outlet of the extruder in the sampling time sequence; regulate the heating temperature of the coating at the current moment based on the correction value.

[0108] Due to the irregularity of the outer contour of the cable itself, there is uneven thickness at local positions, and the thickness unevenness caused by the heating temperature is manifested as continuous and periodically uneven thickness. If the heating temperature is directly feedback-regulated based on the thickness data, it is likely to cause the nylon to thermally degrade.

[0109] Therefore, in the embodiment of the present invention, an infrared thickness gauge is used to measure the thermal radiation of the nylon coating after the coating of the extruder by an infrared sensor, and a sensor is installed at the outlet of the extruder to collect the coating thickness of the cable. It should be noted that during the collection process, the thickness of the cable is collected every 0.1 s, and the specific value can be adjusted by the implementer according to the specific implementation scenario.

[0110] Based on the uneven state performance of the thickness and the consistent situation of the relevant influence of the collaborative influence relationship, analyze the necessary correction situation for temperature adjustment. Preferably, in the embodiment of the present invention, the method for obtaining the correction value includes:

[0111] After obtaining the coating thickness at the outlet of the extruder in the sampling time sequence, calculate the difference between the coating thickness at the current moment and the coating thickness at each moment in the sampling time sequence, then find the average value of all differences and perform normalization processing to obtain the thickness unevenness at the current moment. The greater the overall difference, the more significant the thickness unevenness.

[0112] Furthermore, take the ratio of the thickness unevenness to the collaborative influence value after normalization processing as the correction value at the current moment. The closer the collaborative influence value is to the ratio of 1 to the thickness uneven state, the more balanced the relationship state is, and the lower the necessity for temperature feedback regulation at the next moment.

[0113] When the correction value is less than 1 and the smaller it is, it indicates that the movement state of the cable is insufficient relative to the influence of the temperature, which may lead to insufficient fluidity of the material during extrusion, resulting in uneven thickness. In this case, reducing the temperature to make the material softer and more fluid to improve fluidity will help improve the state of the material and thickness uniformity, and the temperature should be decreased.

[0114] When the correction value is greater than 1 and the larger it is, it indicates that the motion state of the cable is too strong relative to the influence of temperature, and the material may become too fluid and difficult to maintain the required thickness stability. Therefore, the temperature should be increased to maintain the appropriate viscosity and fluidity of the material, so as to control the thickness, and the temperature should be increased.

[0115] Finally, based on the correction value, the heating temperature applied at the current moment is regulated. In the embodiment of the present invention, the product of the correction value at the current moment and the heating temperature is used as the adjusted heating temperature, and the heating temperature at the next moment is regulated to be the adjusted heating temperature. Thus, the temperature during the entire nylon material coating process is regulated.

[0116] It should be noted that, for the convenience of calculation, all the index data involved in the operation in the embodiment of the present invention have undergone data preprocessing, thereby eliminating the influence of dimensions. The specific means of eliminating the influence of dimensions are well-known technical means to those skilled in the art and will not be limited herein.

[0117] The present invention analyzes the attenuation of vibration data at different positions on the cable with distance, considers the variation characteristics of the vibration data at the actual vibration source position, obtains the possibilities of vibration sources at different positions, and at the same time, based on the main direction of the amplitude of the vibration signal at the inlet of the extruder and the amplitude frequency fluctuation of the vibration component signal, determines the influence degree of different positions on the state of each vibration component, reflecting the influence of the cable motion state at the inlet of the extruder analyzed at each sampling position on the nylon coating effect. And using the influence degree as a measure to participate in the prediction of the vibration signal at the inlet of the extruder, a predicted signal is obtained, avoiding the situation of errors when directly predicting based on the vibration data monitored by the sensor at the inlet of the extruder and performing feedback adjustment on the extruder, and improving the accuracy of subsequent feedback adjustment. By judging the cable vibration state within a continuous historical time period through the predicted vibration data, analyzing the different degrees of influence jointly produced by the extruder heating temperature and the vibration state on the coating process, the combined influence value at the current moment is obtained by combining the current cable vibration state and the extruder heating temperature, and based on the relationship between the actually measured cable thickness and the combined influence, feedback adjustment analysis is carried out to obtain the correction value for pre-regulating the heating temperature at future moments, improving the timeliness and efficiency of temperature adjustment, and ensuring the high quality of the cable coating process. The present invention improves the signal prediction accuracy by analyzing the vibration states at multiple positions during the coating process, and considering the historical combined influence of the predicted vibration state and the heating temperature, adjusts the temperature feedback situation to make the temperature adjustment more appropriate and ensure the quality of the cable coating process.

[0118] It should be noted that: the above-mentioned sequence of the embodiments of the present invention is only for description and does not represent the superiority or inferiority of the embodiments. The processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0119] Each embodiment in this specification is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other, and the differences between each embodiment and other embodiments are emphasized.

Claims

1. An environmentally friendly nylon cable coating method, characterized in that, The method includes: At each acquisition position on the cable support in front of the extruder and at the entrance of the extruder, obtain the vibration signal and heating temperature in the sampling time sequence; decompose the vibration signal at the entrance of the extruder into vibration component signals; At each sampling position, according to the approximation between the vibration signal and each vibration component signal in terms of frequency, and analyze the attenuation law of the amplitude of the vibration signal between the sampling position and other sampling positions with distance, to obtain the possible vibration source indicators at each sampling position; According to the deviation between the direction of the vibration signal at the entrance of the extruder and the vertical direction, and the amplitude-frequency ratio of each vibration component signal, combined with the size distribution of the possible vibration source indicators at each sampling position, determine the vibration influence degree of each sampling position on each vibration component signal; Using the vibration influence degree of each sampling position on each vibration component signal as a measure, perform signal prediction and integration on each vibration component signal to obtain the predicted vibration signal at the entrance of the extruder; determine the cable vibration state indicator of the predicted vibration signal through the direction and amplitude-frequency ratio of the predicted vibration signal; Analyze the collaborative relationship between the vibration state of the vibration signal at the entrance of the extruder and the heating temperature in the historical sampling time sequence, combine the heating temperature and the cable vibration state indicator at the current moment to obtain the collaborative influence value at the current moment; Determine the correction value at the current moment through the change in the coating thickness at the exit of the extruder and the collaborative influence value in the sampling time sequence; regulate the heating temperature of the coating at the current moment based on the correction value.

2. The environmentally friendly nylon cable coating method according to claim 1, wherein, The method for obtaining the possible vibration source indicators includes: For any sampling position, calculate the difference between the frequency of the vibration signal at this sampling position and the frequency of each vibration component signal as the frequency difference degree; perform a negative correlation mapping on the minimum value of all frequency difference degrees as the analysis authenticity of this sampling position; Arrange the sampling positions on the cable support in front of the extruder in sequence to obtain a position sequence; in the position sequence, calculate the amplitude difference between each sampling position except the first sampling position and the previous sampling position to obtain the amplitude deviation degree of each sampling position; Based on the amplitude deviation degree, analyze the amplitude change characteristics of this sampling position before and after in the position sequence to obtain the vibration source characteristic index of this sampling position; Combine the analysis authenticity and the vibration source characteristic index of this sampling position to obtain the possible vibration source indicator of this sampling position.

3. The environmentally friendly nylon cable coating method according to claim 2, characterized in that, The method for obtaining the vibration source characteristic index includes: Before this sampling position in the position sequence, calculate the ratio of the sum value of the amplitude deviation degrees of all sampling positions to the sum value of the absolute values of the amplitude deviation degrees of all sampling positions to obtain the previous vibration change characteristic index of this sampling position; After this sampling position in the position sequence, calculate the ratio of the sum value of the amplitude deviation degrees of all sampling positions to the sum value of the absolute values of the amplitude deviation degrees of all sampling positions to obtain the subsequent vibration change characteristic index of this sampling position; Normalize the difference between the subsequent vibration change characteristic index and the previous vibration change characteristic index of this sampling position to obtain the vibration source characteristic index of this sampling position.

4. The environmentally friendly nylon cable coating method according to claim 1, characterized in that, The method for obtaining the vibration influence degree includes: Perform vector decomposition on the vibration signal at the inlet of the extruder to obtain the vibration direction; perform normalization on the angle between the vibration direction and the vertical direction to obtain the influence degree of the extrusion direction; For any vibration component, calculate the ratio of the amplitude to the frequency of the vibration signal of this vibration component to obtain the influence degree of the vibration amplitude of this vibration component; Take the distance between the sampling position with the largest possible index of the vibration source and the inlet position of the extruder as the distance influence degree; for any sampling position, take the ratio of the possible index of the vibration source at this sampling position to the distance influence degree as the influence degree of the vibration source at this sampling position; Combine the influence degree of the extrusion direction, the influence degree of the vibration amplitude of this vibration component, and the influence degree of the vibration source at this sampling position to obtain the influence degree of the vibration of this sampling position on this vibration component.

5. The environmentally friendly nylon cable coating method according to claim 1, characterized in that, The method for obtaining the predicted vibration signal includes: For any vibration component, take the vibration signal of each sampling position in the sampling time series as an externally introduced variable, and use autoregressive integrated moving average to predict this vibration component to obtain the predicted signal affected by this vibration component at each sampling position; Take the influence degree of the vibration of each sampling position on the vibration signal of this vibration component as the weight, and perform weighted averaging on the predicted signals affected by this vibration component at each sampling position to obtain the mean value of the predicted signal of this vibration component; Based on the EMD algorithm, integrate the mean values of the predicted signals of all vibration components to obtain the predicted vibration signal.

6. The environmentally friendly nylon cable coating method according to claim 1, characterized in that, The method for obtaining the cable vibration state index includes: Perform vector decomposition on the predicted vibration signal to obtain the vibration direction of the predicted vibration signal; perform normalization on the angle between the vibration direction of the predicted vibration signal and the vertical direction to obtain the direction influence index of the predicted vibration signal; Take the product of the ratio of the amplitude to the frequency of the predicted vibration signal and the direction influence index as the cable vibration state index of the predicted vibration signal.

7. The environmentally friendly nylon cable coating method according to claim 1, characterized in that, The method for obtaining the co-influence value includes: Perform normalization on the heating temperature at the current moment to obtain the temperature index at the current moment; Obtain the motion state at each moment in the sampling time series; according to the motion state and heating temperature at each moment, map all moments in the sampling time series to a two-dimensional co-ordinate system; the horizontal axis of the two-dimensional co-ordinate system is the motion state, and the vertical axis is the heating temperature; Use the PCA algorithm for the data points in the two-dimensional co-ordinate system to obtain the principal component direction; perform normalization on the angle between the principal component direction and the horizontal axis of the co-ordinates to obtain the temperature co-efficient; Take the product of the temperature co-efficient and the temperature index as the temperature influence value; take the product of the negatively correlated mapped value of the temperature co-efficient and the cable vibration state index as the vibration influence value; take the sum of the temperature influence value and the vibration influence value as the co-influence value at the current moment.

8. The environmentally friendly nylon cable coating method according to claim 1, characterized in that, The method for obtaining the correction value includes: Obtain the coating thickness at the outlet of the extruder in the sampling time series; after calculating the difference between the coating thickness at the current moment and the coating thickness at each moment in the sampling time series, find the mean value of all differences and perform normalization to obtain the thickness non-uniformity at the current moment; Take the ratio of the thickness non-uniformity to the co-influence value after normalization as the correction value at the current moment.

9. The environmentally friendly nylon cable coating method according to claim 1, characterized in that, The regulation of the heating temperature coated at the current moment based on the correction value includes: Taking the product of the correction value at the current moment and the heating temperature as the adjusted heating temperature; regulating the heating temperature at the next moment to be the adjusted heating temperature.

10. The environmentally friendly nylon cable coating method according to claim 1, characterized in that, The method for obtaining the vibration component signal includes: Using the EMD decomposition algorithm for the vibration signal at the inlet of the extruder to obtain each IMF component as the vibration component signal.

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