PLC-based high-precision wire arranging and drawing machine intelligent control method and system

Abstract

This invention belongs to the field of wire drawing machine control technology, and provides a PLC-based intelligent control method and system for a high-precision wire drawing machine. The method includes: acquiring process parameters to generate an ideal speed smooth trajectory for the main drawing motor; acquiring and preprocessing the raw tension signal collected by the tension sensor; identifying whether there is a deviation in the actual tension trend based on the preprocessed signal; if so, performing an overall speed correction on the ideal speed smooth trajectory at a response frequency lower than the speed control cycle of the main drawing motor, and controlling the motor operation according to the corrected trajectory. This invention effectively distinguishes between actual process tension changes and mechanical vibration noise by decomposing speed control into smooth trajectory generation and trend correction, avoiding excessive response of the control system to noise, ensuring the instantaneous speed uniformity during wire drawing, and improving the stability and quality of wire production.

Description

Technical Field

[0001] This invention relates to the field of wire drawing machine control technology, and in particular to a PLC-based intelligent control method and system for a high-precision wire drawing machine. Background Technology

[0002] In the field of high-end equipment manufacturing, high-precision wire drawing machines are core equipment for producing ultra-fine metal wires. In actual high-speed production environments, the mechanical components inside the wire drawing machine (such as traction wheels, drawing die holders, and wire laying mechanisms) will generate mechanical vibrations at natural and random frequencies. These vibrations are transmitted to the tension sensor, causing high-frequency noise unrelated to the actual tension change to be superimposed on its output signal.

[0003] When traditional PLC control systems receive tension signals superimposed with vibration noise, their internal filters, due to their limited effectiveness in filtering wide-bandwidth, random noise, often misinterpret this noise as genuine wire tension fluctuations. Based on its preset control logic, the PLC immediately issues commands to frequently, minutely, and unnecessarily adjust the motor speed in an attempt to eliminate these noise-induced "deviations." This over-response leads to accelerated wear of the motor driver and mechanical components, and causes the wire to experience unstable instantaneous pulling forces during the drawing process. Ultimately, this results in microscopic defects on the surface of the ultra-fine metal wire, affecting its geometric accuracy and mechanical property consistency, and even accelerating the failure of the drawing die.

[0004] Therefore, how to effectively distinguish between actual process tension changes and vibration noise, and avoid excessive intervention of the control system in noise, so as to ensure high stability and high quality of wire production, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] This invention provides a PLC-based intelligent control method and system for a high-precision wire drawing machine. It aims to solve the problems caused by mechanical vibration interfering with the control system when the high-precision wire drawing machine is running at high speed. This interference leads to various noises superimposed on the output signal of the tension sensor, which in turn causes misjudgment by the PLC system, resulting in frequent and unnecessary speed adjustments of the motor. Ultimately, this leads to problems such as decreased wire quality, increased equipment energy consumption, increased maintenance costs, and accelerated mold wear.

[0006] On one hand, the present invention provides a PLC-based intelligent control method for a high-precision wire drawing machine, which includes: Obtain the process parameters of the metal wire to be generated, and generate an ideal speed smooth trajectory for the main stretching motor based on the process parameters; the ideal speed smooth trajectory is the smooth speed change path that the main stretching motor should follow when there is no external instantaneous interference. Acquire the original tension signal of the metal wire to be generated, collected by the tension sensor installed on the wire drawing machine; The original tension signal is preprocessed to obtain a preprocessed tension signal; the preprocessing includes filtering out the instantaneous noise signal of the target frequency and / or the signal corresponding to the quasi-periodic vibration component in the original tension signal; Based on the preprocessed tension signal, trend identification is performed to determine whether there is a deviation in the true tension trend that needs to be corrected. If the actual tension trend deviation exists, the ideal speed smoothing trajectory is corrected as a whole at a response frequency lower than the speed control cycle of the main tension motor to obtain the corrected speed trajectory. The main tension motor is controlled to operate according to the corrected speed trajectory.

[0007] On the other hand, the present invention also provides a PLC-based intelligent control system for a high-precision wire drawing machine, which includes: The planning module is used to obtain the process parameters of the metal wire to be generated, and generate an ideal speed smooth trajectory of the main stretching motor based on the process parameters; the ideal speed smooth trajectory is the smooth speed change path that the main stretching motor should follow when there is no external instantaneous interference. The acquisition module is used to acquire the original tension signal of the metal wire to be generated, which is collected by the tension sensor installed on the wire drawing machine; The preprocessing module is used to preprocess the original tension signal to obtain a preprocessed tension signal; the preprocessing includes filtering out the instantaneous noise signal of the target frequency and / or the signal corresponding to the quasi-periodic vibration component in the original tension signal; The identification module is used to identify trends based on the preprocessed tension signal and determine whether there is a deviation in the true tension trend that needs to be corrected. The correction module is used to perform overall speed correction on the ideal speed smoothing trajectory at a response frequency lower than the speed control cycle of the main tension motor if there is a deviation from the actual tension trend, so as to obtain a corrected speed trajectory. The control module is used to control the operation of the main tension motor according to the corrected speed trajectory.

[0008] The present invention provides a PLC-based intelligent control method and system for high-precision wire drawing machines. By acquiring process parameters, it generates an ideal speed smooth trajectory for the main stretching motor. The system preprocesses the raw signals collected by the tension sensor to filter out instantaneous noise and quasi-periodic vibration components. Based on the preprocessed signals, it identifies the actual tension trend deviation. Only when a deviation exists is the system corrected overall for the ideal speed smooth trajectory at a response frequency lower than the motor speed control cycle. This effectively distinguishes between actual process tension changes and mechanical vibration noise, avoids excessive response of the control system to noise, ensures the uniformity of instantaneous speed during wire drawing, and improves the stability and quality of ultra-fine metal wire production. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0010] Figure 1 This is a flowchart illustrating the intelligent control method for a high-precision wire drawing machine based on PLC provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of the structure of the intelligent control system for a high-precision wire drawing machine based on PLC provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the electronic device provided in an embodiment of the present invention. Detailed Implementation

[0011] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0012] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0013] Traditional high-precision wire drawing machines generate mechanical vibrations at both natural and random frequencies during high-speed operation, due to the traction wheel, drawing die, wire drawing mechanism, and motor itself. These vibrations are transmitted to the tension sensor, resulting in high-frequency noise unrelated to actual tension changes superimposed on the sensor's output signal. Because the digital filters within the PLC system have limited filtering effectiveness for this wide-bandwidth, random mechanical vibration noise, the PLC may misinterpret these noise signals as genuine wire tension fluctuations. Frequent, minor, and unnecessary motor speed adjustments based on these noise signals negatively impact the entire control system and mechanical components, potentially leading to a decline in wire quality and increasing energy consumption and maintenance costs.

[0014] To address the aforementioned problems, the present invention provides the following technical solution: Figure 1 This is a flowchart illustrating the intelligent control method for a high-precision wire drawing machine based on PLC provided in an embodiment of the present invention.

[0015] like Figure 1 As shown, the intelligent control method for a high-precision wire drawing machine based on PLC provided in this embodiment of the invention mainly includes the following steps: 101. Obtain the process parameters of the metal wire to be generated, and generate the ideal speed smooth trajectory of the main stretching motor according to the process parameters; In a specific implementation, this method is executed in a PLC, which can select a suitable controller model based on actual needs. Before production begins, the PLC can plan and generate an ideal smooth speed trajectory for the main stretching motor based on process parameters such as the type of wire, target stretching speed, stretching ratio, and die configuration of the metal to be produced. This ideal smooth speed trajectory describes the entire speed change path of the motor from start-up to stable operation and then to shutdown, representing the smoothest speed change curve that the motor should follow when there are no external instantaneous disturbances such as mechanical vibration.

[0016] The ideal speed smooth trajectory includes a start-up phase, a stable operation phase, and a stopping phase; During the start-up phase, an S-shaped acceleration curve is generated by limiting the rate of change of acceleration, allowing the main tension motor speed to rise smoothly from zero to the target speed. During the stable operation phase, the speed is kept constant at the target speed. During the stopping phase, an S-shaped deceleration curve is generated by limiting the rate of change of deceleration, allowing the main tension motor speed to drop smoothly from the target speed to zero.

[0017] In detail, within the PLC, based on parameters such as the type of metal wire to be produced, the set target stretching speed, the required stretching ratio, and the current mold configuration, the PLC can plan a complete speed change path throughout the entire production process. This path is divided into three stages: startup, stable operation, and shutdown. During startup, the PLC generates an S-shaped acceleration curve. This means that the motor acceleration is not abrupt, but starts from a small value, increases linearly to a maximum value according to a preset jerk (rate of change of acceleration), and then linearly decreases to zero, allowing the motor speed to start from zero and undergo a smooth, shock-free acceleration process before finally reaching the target speed. During stable operation, the PLC commands the main stretching motor to maintain a constant speed at the target speed as much as possible. During shutdown, the PLC generates an S-shaped deceleration curve, similar in principle to the acceleration stage, limiting the rate of change of deceleration to allow the motor speed to smoothly and gently decrease from the target speed to a complete stop.

[0018] This embodiment eliminates mechanical shocks and speed fluctuations that may occur during motor startup and shutdown by generating a smooth speed trajectory that includes S-shaped acceleration and deceleration curves throughout the entire process. This provides an ideal and stable operating benchmark for the entire wire drawing process, minimizing the need for the control system to actively intervene in the motor's operating status, and is the foundation for achieving high-precision and high-stability wire drawing control.

[0019] 102. Obtain the original tension signal of the metal wire to be generated, collected by the tension sensor installed on the wire drawing machine; During production, the HBM C2 tension sensor installed on the guide wheel can collect the raw tension signal in real time. This raw tension signal inevitably contains mechanical vibration noise generated by the high-speed operation of the wire drawing machine. For example, there are instantaneous noise signals at the target frequency (such as high-frequency random jitter caused by the high-speed rotation of the traction wheel) and signals of quasi-periodic vibration components (such as specific frequency fluctuations caused by microscopic wear of the non-driving guide wheel bearings).

[0020] 103. The original tension signal is preprocessed to obtain a preprocessed tension signal; After acquiring the original tension signal, the PLC preprocesses it. The core of the preprocessing is to filter out the instantaneous noise signal of the target frequency (such as high-frequency random jitter caused by the high-speed rotation of the traction wheel) and / or the signal of quasi-periodic vibration components (such as specific frequency fluctuations caused by microscopic wear of the non-driving guide wheel bearing) in the original signal, thereby obtaining a preprocessed tension signal that better reflects the actual process tension changes.

[0021] In a specific implementation, when preprocessing the original tension signal, only the instantaneous noise signal of the target frequency in the original signal (such as high-frequency random jitter caused by the high-speed rotation of the traction wheel) can be filtered out. The process is as follows: The original tension signal is subjected to preliminary noise reduction processing to filter out the instantaneous noise signal of the target frequency in the original tension signal, and the preliminary noise reduction signal is used as the preprocessed tension signal. The preliminary noise reduction process includes: using a moving average filtering algorithm to calculate the average value of multiple continuously collected tension data points within a first preset time window, as the preliminary noise reduction signal; or using a median filtering algorithm to sort all data points within the first preset time window and select the median value as the preliminary noise reduction signal.

[0022] In detail, the purpose of this preliminary noise reduction process is to filter out high-frequency, random, transient noise signals generated by the high-speed operation of the equipment. Specifically, a moving average filtering algorithm or a median filtering algorithm can be used.

[0023] If a moving average filtering algorithm is used, the PLC's internal program defines a first preset time window. For example, the length of this first preset time window might correspond to the time required to collect 50 consecutive tension data points. Assuming the sampling period of the tension sensor is 1 millisecond, the length of this first preset time window would be 50 milliseconds. Within this 50-millisecond first preset time window, the PLC calculates the arithmetic mean of the 50 data points and outputs this average as the initial noise reduction signal for the current moment. This process is repeated continuously as new data arrives.

[0024] Its calculation formula can be expressed as:

[0025] in, This is the tension value corresponding to the preprocessed tension signal, where n represents the nth tension data point at the current moment. These are the sampled values ​​of the i original tension signals. W is the size of the first preset time window.

[0026] If a median filtering algorithm is used, the PLC also uses the first preset time window. Within each window, the PLC sorts all tension data points according to their numerical values ​​and then selects the value located in the middle of the sequence as the initial noise-reduced signal output for the current moment. This method is particularly effective in eliminating abnormally high-amplitude spike noise caused by mechanical shocks, etc. After processing by any one or two of the above algorithms, the resulting initial noise-reduced signal is used as the preprocessed tension signal for the subsequent trend recognition step.

[0027] In a specific implementation, when preprocessing the original tension signal, not only can the instantaneous noise signal of the target frequency (e.g., high-frequency random jitter caused by the high-speed rotation of the traction wheel) be filtered out from the original signal, but also the quasi-periodic vibration component (e.g., specific frequency fluctuations caused by microscopic wear of the non-driving guide wheel bearing) can be filtered out. The process is as follows: The original tension signal is subjected to preliminary noise reduction processing to filter out the instantaneous noise signal of the target frequency in the original tension signal, and a preliminary noise-reduced signal is obtained. Frequency analysis is performed on the preliminary noise reduction signal to identify whether there are quasi-periodic vibration components introduced by auxiliary components of the equipment in the preliminary noise reduction signal; If the quasi-periodic vibration component is identified, the center frequency of the preset adaptive digital notch filter is adjusted according to the dominant frequency of the quasi-periodic vibration component, and the adaptive digital notch filter is used to filter the preliminary noise reduction signal to remove the signal corresponding to the quasi-periodic vibration component, thereby obtaining the preprocessed tension signal.

[0028] In detail, this embodiment provides a more refined preprocessing method to address quasi-periodic vibration components introduced by microscopic wear of auxiliary equipment components (such as non-driving guide wheels), which mainly includes the following three steps: The first step, similar to the previous one, is to perform preliminary noise reduction on the original tension signal, for example, by using a moving average filter to filter out high-frequency transient noise and obtain a preliminary noise-reduced signal.

[0029] The second step involves the PLC periodically capturing a segment of the signal and analyzing its frequency distribution using algorithms such as short-time Fourier transform. By monitoring for sustained energy peaks within a preset frequency range (e.g., 50-100 Hz), the presence of quasi-periodic vibration components is identified. If the energy of a frequency component within this range consistently exceeds a preset threshold, the presence of a quasi-periodic vibration component is determined, and its dominant frequency is recorded.

[0030] Specifically, the process of identifying whether there are quasi-periodic vibration components introduced by auxiliary components of the equipment in the preliminary noise reduction signal is as follows: Periodically extract signal segments of a preset length from the initial noise-reduced signal; perform frequency analysis on the signal segments using a short-time Fourier transform algorithm to obtain the spectral distribution of the signal in the frequency domain; monitor the energy values ​​of each frequency component in the spectral distribution within a preset frequency range; when the energy value of any frequency component within the frequency range continuously exceeds a preset energy threshold, it is determined that the quasi-periodic vibration component exists, and the dominant frequency and amplitude of the frequency component containing the quasi-periodic vibration component are recorded.

[0031] In detail, the PLC periodically performs an identification task. Within each cycle, it extracts a pre-defined signal segment from the continuous initial noise-reduced signal data stream. For example, it extracts a segment containing 256 data points every 100 milliseconds, corresponding to a time length of 256 milliseconds. For each extracted signal segment, the PLC runs a short-time Fourier transform algorithm. This algorithm converts the time-domain signal into a frequency-domain spectral distribution, visually displaying which frequency components are contained within the signal segment and their corresponding energy values ​​(or amplitudes). After the transformation, the PLC focuses on monitoring a pre-defined frequency range, such as 50 Hz to 100 Hz. It analyzes the energy value of each frequency component falling within this range. If, within this range, the energy value of a specific frequency component is detected to be consistently exceeding a pre-set energy threshold rather than being sporadic, then a quasi-periodic vibration component is identified. In this case, the PLC records the frequency value of this specific frequency component as the dominant frequency and its energy or amplitude value for subsequent use by the adaptive notch filter.

[0032] The third step involves the PLC activating an adaptive digital notch filter if quasi-periodic vibration components are detected. The core parameter of this filter is its center frequency. The PLC dynamically adjusts the center frequency of the notch filter to the dominant frequency identified in the previous step. Subsequently, this adjusted notch filter is used to filter the initial noise-reduced signal. The notch filter can extremely precisely suppress frequency components within a narrow bandwidth near its center frequency, effectively eliminating quasi-periodic vibration signals introduced by auxiliary components. The signal obtained after this processing is a cleaner, more representative pre-processed tension signal that better reflects the actual process tension changes.

[0033] This embodiment solves the problem of quasi-periodic vibration interference caused by microscopic wear of auxiliary components of equipment, which is difficult to eliminate with conventional filtering, by introducing frequency analysis and adaptive notch filtering. This further purifies the tension signal, ensuring that subsequent trend identification steps will not make misjudgments or hesitate in judgment due to this complex interference between noise and trend, thus ensuring the accuracy of the control system's decision-making.

[0034] 104. Based on the preprocessed tension signal, perform trend identification to determine whether there is a deviation in the true tension trend that needs to be corrected; In a specific implementation process, this step can be achieved in the following two ways: The first method involves calculating the average tension deviation between the average value of the preprocessed tension signal and the preset target tension value within a second preset time window; and / or calculating the slope of the change of the preprocessed tension signal within the second preset time window; if at least one of the following conditions is met—the average tension deviation exceeding a preset tolerance deviation, the slope of change continuously deviating from zero, and the slope of change continuously indicating a change rate greater than a preset rate—it is detected whether the duration of continuous satisfaction exceeds a preset duration threshold; if the duration of continuous satisfaction exceeds the preset duration threshold, it is confirmed that the actual tension trend deviation exists.

[0035] In detail, a second preset time window can be defined, such as a 500-millisecond time window. Within this window, the PLC calculates the average value of the pre-processed tension signal, and then subtracts the preset target tension value from this average value to obtain the average tension deviation. Simultaneously, it can also calculate the slope of the signal change within this window, i.e., the rate and direction of tension change. The judgment logic is as follows: if the calculated average tension deviation exceeds the preset tolerance deviation (e.g., when the target tension is 100 Newtons, the tolerance deviation is ±1 Newton), or the slope of the signal change continuously deviates from zero (indicating that the tension is continuously rising or falling), or the absolute value of the slope change continuously exceeds a preset rate value (indicating that the tension is changing too quickly), as long as at least one of these conditions is met, the PLC will proceed to the next judgment step. Next, it will detect the duration for which these abnormal conditions are continuously met. For this purpose, the system presets a duration threshold, such as 1000 milliseconds. Only when the duration for which one or more abnormal conditions are met exceeds this 1000-millisecond threshold will the PLC finally confirm the existence of a real tension trend deviation that needs correction. Conversely, if the abnormal condition only occurs momentarily or lasts for a very short time, it is considered an occasional fluctuation that does not require correction.

[0036] This embodiment effectively avoids unnecessary speed corrections triggered by instantaneous jitter or short-term glitches in the tension signal by introducing multiple judgment conditions such as time windows, tolerance deviations, and duration thresholds. This "delayed confirmation" mechanism ensures that only those persistent and statistically significant true process trends are identified, greatly improving the robustness and anti-interference capability of the control system.

[0037] The second method involves collecting multi-dimensional trend judgment indicators. These indicators include the average tension deviation calculated within a third preset time window, the stability of the slope of the average tension value calculated within multiple consecutive fourth preset time windows, the suppression degree of local fluctuation amplitude of the tension signal calculated within a fifth preset time window, and the matching degree between the current tension change characteristics and a preset process change characteristic template. The length of the third preset time window is greater than the lengths of the fourth and fifth preset time windows. The preset process change characteristic template is used to characterize the tension change trend caused by mold wear. A higher matching degree indicates a better match between the current tension change trend and the tension change trend caused by mold wear. The average tension deviation, stability, inhibition degree, and matching degree are weighted and calculated to obtain a confidence score that characterizes the degree of confidence in the trend. If the confidence score continues to exceed a preset score threshold within a preset confirmation period, the existence of the true tension trend deviation is confirmed.

[0038] In detail, this embodiment proposes a more intelligent and comprehensive trend judgment mechanism, namely, calculating a "confidence score". The PLC collects four dimensions of indicators in parallel. The first is the long-term average tension deviation, calculated within a relatively long third preset time window (e.g., 1 second). The second is the stability of the slope of the tension average change, quantified by calculating the average slope in multiple consecutive, shorter fourth preset time windows (e.g., each 200 milliseconds), and then evaluating whether the signs of these slopes are consistent and whether the numerical differences are small. The third is the local fluctuation suppression degree, calculated within a shorter fifth preset time window (e.g., 100 milliseconds) for the amplitude of signal fluctuations (e.g., standard deviation). The smaller the value, the more effectively the fluctuations caused by noise or local material differences have been suppressed. The fourth is the matching degree, comparing the current tension change characteristics with a preset process change characteristic template, which is pre-stored by the system according to physical mechanisms, such as describing a typical slow and monotonous upward trend of tension caused by mold wear. A high matching degree means that the current tension change is likely caused by real process reasons such as mold wear, rather than random interference. After collecting these four indicators, the PLC assigns a preset weight to each indicator (e.g., long-term deviation weight 0.4, slope stability weight 0.3, inhibition weight 0.2, and matching weight 0.1), performs a weighted summation, and calculates a total confidence score between 0 and 1. This score represents the system's degree of confidence in the judgment that "there is indeed a real process trend that needs correction." Finally, the PLC monitors this confidence score. Only when the score continuously exceeds a preset high score threshold (e.g., 0.8) within a preset confirmation period (e.g., 500 milliseconds) will a real tension trend deviation be finally confirmed.

[0039] This embodiment significantly improves the robustness and accuracy of tension trend judgment by constructing a multi-dimensional confidence assessment system. It no longer relies on a single threshold but integrates evidence from multiple aspects, including long-term deviation, trend consistency, anti-interference capability, and physical mechanism matching. This allows the system to clearly distinguish between genuine process drift and complex fluctuations caused by local material differences in the wire, which do not constitute a long-term trend. Corrective actions are only taken when there is a "high degree of confidence," avoiding hesitation and misoperation in judgment.

[0040] In some preferred embodiments, a specific example is given below. Suppose that during the wire drawing process, due to slight wear of the die, the tension on the wire begins to increase slowly and continuously during the stretching process.

[0041] in this case: 1. The average tension deviation calculated within the third preset time window may show that the tension is slightly higher than the target value.

[0042] 2. The stability of the slope of the average tension change calculated within multiple consecutive fourth preset time windows will show a continuous, small-amplitude positive slope, indicating that the tension is showing a stable upward trend.

[0043] 3. The suppression of local fluctuations in the tension signal calculated within the fifth preset time window may still be low, because tension changes caused by mold wear are usually gradual and will not immediately lead to violent fluctuations.

[0044] 4. Comparing the current tension change characteristics with the preset tension change characteristic template caused by mold wear may yield a high degree of matching, clearly indicating the possibility of mold wear.

[0045] At this point, a weighted calculation can be performed on the aforementioned average tension deviation, stability, suppression, and matching degree. Since mold wear is a long-term issue requiring attention, the matching degree may be given a higher weight. Even if the contributions of average tension deviation and local fluctuation suppression are relatively small, the combined effect of a stable upward trend and high matching degree will result in a confidence score that consistently exceeds a preset threshold. When this confidence score consistently meets the conditions within a preset confirmation period, the system will confirm the existence of a genuine tension trend deviation and trigger a correction to the ideal speed smoothing trajectory of the main tension motor, thereby adjusting production parameters in a timely manner and preventing a decline in wire quality due to mold wear. In contrast, if only a single tension deviation threshold is relied upon, this slow and continuous deviation may go undetected for a long time because it has not reached the instantaneous threshold, ultimately affecting product quality.

[0046] In a specific implementation, the average tension deviation is obtained as follows: within the third preset time window, the average value of the preprocessed tension signal is calculated, and the difference between this average value and the preset target tension value is calculated. This difference is used as the average tension deviation. The average tension deviation aims to quantify the overall offset between the current tension level and the desired target tension. By averaging the preprocessed tension signal within the third preset time window, short-term fluctuations can be effectively filtered out, thereby obtaining a more representative average tension value. This average tension value is then compared with the target tension value to reflect the macroscopic accuracy of tension control.

[0047] The stability is obtained by: calculating the slope of the change of the average value of the preprocessed tension signal within each of the multiple consecutive fourth preset time windows; if the direction of all the slopes is consistent and the standard deviation of all the slopes is lower than a preset stability threshold, the slope stability is determined to be a first preset score; if the direction of all the slopes is consistent and / or the standard deviation of all the slopes is at least partially not lower than the preset stability threshold, the slope stability is determined by discounting the first preset score based on the proportion of consistent signs and the degree of deviation of the standard deviation from the stability threshold.

[0048] Specifically, slope stability is used to assess the persistence and consistency of tension change trends. For slope stability, the PLC first calculates the signal change slope for each window within multiple consecutive fourth preset time windows. If the signs of all these slopes are consistent (e.g., all positive, indicating a continuous rise), and the standard deviation of these slope values ​​is less than a preset stability threshold, then the slope stability is directly assigned a highest first preset score (e.g., 1.0). If the signs are not completely consistent or the standard deviation is too large, the first preset score is "discounted" based on the proportion of consistent signs and the degree to which the standard deviation exceeds the stability threshold, such as by multiplying it by a coefficient less than 1, as the final value of the indicator.

[0049] The suppression degree is obtained as follows: within the fifth preset time window, the running standard deviation of the preprocessed tension signal relative to the average value within the fifth preset time window is calculated. If the running standard deviation is lower than a preset suppression threshold, the value of the local fluctuation suppression degree is determined to be a second preset score. If the running standard deviation is not lower than the preset suppression threshold, the value of the local fluctuation suppression degree is determined by discounting the second preset score based on the ratio of the suppression threshold to the standard deviation. In detail, the suppression degree is used to monitor local fluctuations in the tension signal. For the local fluctuation suppression degree, the PLC calculates the operating standard deviation of the preprocessed tension signal within a fifth preset time window. If this standard deviation is lower than a preset suppression threshold, the local fluctuation suppression degree is assigned the highest second preset score (e.g., 1.0). If it is equal to or higher than the suppression threshold, the second preset score is discounted according to the ratio of the suppression threshold to the actual standard deviation (this ratio is less than 1) to obtain the final value.

[0050] The matching degree is obtained by comparing the current trend of the preprocessed tension signal with the trend of tension change caused by mold wear in the preset process change feature template, and taking the similarity percentage obtained by comparison as the value of the matching degree.

[0051] In detail, the matching degree aims to identify whether the current tension change trend matches a specific process anomaly pattern (such as mold wear) through pattern recognition. For the matching degree, the PLC preprocesses the overall waveform of the tension signal over a recent period and compares it with a pre-stored feature template describing the slow upward trend of tension caused by mold wear. A common method is to calculate the correlation coefficient between the two waveforms, and the obtained correlation coefficient (a percentage value between 0 and 1) is the value of the matching degree.

[0052] 105. If the actual tension trend deviation exists, the ideal speed smoothing trajectory is corrected as a whole at a response frequency lower than the speed control cycle of the main tension motor to obtain the corrected speed trajectory. In a specific implementation, when a real trend deviation is confirmed, the PLC does not immediately make rapid adjustments. Instead, it performs a comprehensive speed correction on the previously generated ideal speed smoothing trajectory at a response frequency lower than the speed control cycle of the main tension motor. For example, if the speed control cycle of the main tension motor is 1 millisecond, the correction frequency in this step might be once every 500 milliseconds. This correction is not a fine-tuning of the instantaneous speed, but a slow, gradual increase or decrease of the baseline value of the entire speed trajectory, thereby obtaining a corrected speed trajectory.

[0053] The specific correction process is as follows: The correction amount is generated by a proportional-integral controller. The control cycle of the proportional-integral controller is set to be a preset multiple greater than the speed control cycle of the main tension motor. The proportional coefficient and integral coefficient of the proportional-integral controller are set to preset ratios that are less than the parameter values ​​of the traditional controller. The correction amount is gradually added to the reference speed value of the ideal speed smooth trajectory, so that the target speed of the main tension motor completes a smooth transition from the current reference speed to the corrected reference speed within a preset adjustment time, and the speed change rate during the transition is less than the preset change rate.

[0054] In detail, once a genuine tension trend deviation is confirmed, the PLC activates a dedicated proportional-integral (PI) controller to generate a speed correction. This PLC is intentionally designed to have a "slow" response. First, its control cycle is set much longer than the speed control cycle of the main tension motor itself. For example, if the main motor's speed control cycle is 1 millisecond, the PLC cycle is set to 500 milliseconds, a multiple of its preset value (500 times). Second, the proportional and integral coefficients of this controller are also set much smaller than typical values ​​in traditional control schemes, for example, only one-tenth of the traditional parameter values, to ensure that the correction generated in each control cycle is extremely small. After calculating the correction, the PLC does not directly replace the current target speed, but rather gradually adds this small correction to the current reference speed value of the ideal speed smoothing trajectory. For example, if the tension is detected to be consistently high, requiring a reduction in the reference speed from 1000 rpm to 999 rpm, the PLC will not do so in one step, but will accumulate a correction of -0.01 rpm every 500 milliseconds. The entire adjustment process lasts for a preset adjustment time (e.g., 10 seconds), allowing the target speed of the main tension motor to transition in an extremely smooth and constant-slope manner. Throughout the transition, the rate of change of speed (i.e., jerk) is always controlled below a preset, very low rate of change threshold to ensure there is no sense of impact.

[0055] The aforementioned correction amount It can be represented as: ; in, It represents the tension trend deviation during the nth control cycle. and These are the proportional and integral coefficients, whose values ​​are much smaller than those in traditional PID controllers to ensure slow correction. The sum (integral term) of all tension trend deviations from the start of control to the current moment. This sum is used to correct for long-term, persistent deviations in the true tension trend, ensuring that the speed adjustment of the main tension motor allows the wire tension to gradually return to the target value.

[0056] This embodiment uses a slow-cycle, small-parameter proportional-integral controller and a gradually accumulating correction method to ensure that the speed correction action is smooth and gradual, avoiding the instantaneous speed impact on the wire caused by the correction action itself.

[0057] 106. Control the operation of the main tension motor according to the corrected speed trajectory.

[0058] Specifically, based on this corrected speed trajectory, the PLC sends instructions to the driver of the main stretching motor to control the motor's operation, ensuring that it follows a smooth preset trajectory most of the time, and only makes gentle adjustments when there are clear and persistent process deviations.

[0059] This embodiment of the PLC-based intelligent control method for high-precision wire drawing machines generates an ideal speed smooth trajectory for the main drawing motor by acquiring process parameters. It preprocesses the raw signals collected by the tension sensor to filter out instantaneous noise and quasi-periodic vibration components. Based on the preprocessed signals, it identifies the actual tension trend deviation. Only when a deviation exists is the overall speed correction of the ideal speed smooth trajectory performed at a response frequency lower than the motor speed control cycle. This effectively distinguishes between actual process tension changes and mechanical vibration noise, avoids excessive response of the control system to noise, ensures the instantaneous speed uniformity during wire drawing, and improves the stability and quality of ultra-fine metal wire production.

[0060] Based on the same general inventive concept, this invention also protects a PLC-based intelligent control system for a high-precision wire drawing machine. The following describes the PLC-based intelligent control system for a high-precision wire drawing machine provided by this invention. The PLC-based intelligent control system described below and the PLC-based intelligent control method for a high-precision wire drawing machine described above can be referred to in correspondence.

[0061] Figure 2 This is a schematic diagram of the structure of the intelligent control system for a high-precision wire drawing machine based on PLC provided in an embodiment of the present invention, as shown below. Figure 2 As shown, the PLC-based intelligent control system for high-precision wire drawing machine in this embodiment includes a planning module 21, an acquisition module 22, a preprocessing module 23, an identification module 24, a correction module 25, and a control module 26.

[0062] The planning module is used to obtain the process parameters of the metal wire to be generated, and generate an ideal speed smooth trajectory of the main stretching motor based on the process parameters; the ideal speed smooth trajectory is the smooth speed change path that the main stretching motor should follow when there is no external instantaneous interference. The acquisition module is used to acquire the original tension signal of the metal wire to be generated, which is collected by the tension sensor installed on the wire drawing machine; The preprocessing module is used to preprocess the original tension signal to obtain a preprocessed tension signal; the preprocessing includes filtering out the instantaneous noise signal of the target frequency and / or the signal corresponding to the quasi-periodic vibration component in the original tension signal; The identification module is used to identify trends based on the preprocessed tension signal and determine whether there is a deviation in the true tension trend that needs to be corrected. The correction module is used to perform overall speed correction on the ideal speed smoothing trajectory at a response frequency lower than the speed control cycle of the main tension motor if there is a deviation from the actual tension trend, so as to obtain a corrected speed trajectory. The control module is used to control the operation of the main tension motor according to the corrected speed trajectory.

[0063] Figure 3 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. The electronic device may include: a processor 310, a communication interface 320, a memory 330, and a communication bus 340. The processor 310, communication interface 320, and memory 330 communicate with each other via the communication bus 340. The processor 310 can call logic instructions from the memory 330 to execute a PLC-based intelligent control method for a high-precision wire drawing machine.

[0064] Furthermore, the logical instructions in the aforementioned memory 330 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0065] It should be noted that all relevant information that may be involved in the various embodiments of the present invention is processed in strict accordance with the requirements of laws and regulations, following the principles of legality, legitimacy, and necessity, based on the reasonable purpose of the business scenario, and is information that users actively provide or generate during the use of the product / service, as well as information obtained with user authorization.

[0066] The information processed by this invention may vary depending on the specific product / service scenario and should be based on the specific scenario in which the user uses the product / service. This may involve user account information, device information, or other related information. This invention will treat the relevant information and its processing with the utmost diligence.

[0067] This invention places great emphasis on the security of relevant information and has adopted reasonable and feasible security protection measures that comply with industry standards to protect user information and prevent unauthorized access, public disclosure, use, modification, damage or loss of relevant information.

[0068] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0069] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A PLC-based intelligent control method for a high-precision wire drawing machine, characterized in that, include: Obtain the process parameters of the metal wire to be generated, and generate an ideal speed smooth trajectory for the main stretching motor based on the process parameters; the ideal speed smooth trajectory is the smooth speed change path that the main stretching motor should follow when there is no external instantaneous interference. Acquire the original tension signal of the metal wire to be generated, collected by the tension sensor installed on the wire drawing machine; The original tension signal is preprocessed to obtain a preprocessed tension signal; the preprocessing includes filtering out the instantaneous noise signal of the target frequency and / or the signal corresponding to the quasi-periodic vibration component in the original tension signal; Based on the preprocessed tension signal, trend identification is performed to determine whether there is a deviation in the true tension trend that needs to be corrected. If the actual tension trend deviation exists, the ideal speed smoothing trajectory is corrected as a whole at a response frequency lower than the speed control cycle of the main tension motor to obtain the corrected speed trajectory. The main tension motor is controlled to operate according to the corrected speed trajectory.

2. The intelligent control method for a high-precision wire drawing machine based on PLC according to claim 1, characterized in that, The original tension signal is preprocessed to obtain a preprocessed tension signal, including: The original tension signal is subjected to preliminary noise reduction processing to filter out the instantaneous noise signal of the target frequency in the original tension signal, and the preliminary noise reduction signal is used as the preprocessed tension signal. The preliminary noise reduction process includes: using a moving average filtering algorithm to calculate the average value of multiple continuously collected tension data points within a first preset time window, as the preliminary noise reduction signal; or using a median filtering algorithm to sort all data points within the first preset time window and select the median value as the preliminary noise reduction signal.

3. The intelligent control method for a high-precision wire drawing machine based on PLC according to claim 1, characterized in that, The original tension signal is preprocessed to obtain a preprocessed tension signal, including: The original tension signal is subjected to preliminary noise reduction processing to filter out the instantaneous noise signal of the target frequency in the original tension signal, and a preliminary noise-reduced signal is obtained. Frequency analysis is performed on the preliminary noise reduction signal to identify whether there are quasi-periodic vibration components introduced by auxiliary components of the equipment in the preliminary noise reduction signal; If the quasi-periodic vibration component is identified, the center frequency of the preset adaptive digital notch filter is adjusted according to the dominant frequency of the quasi-periodic vibration component, and the adaptive digital notch filter is used to filter the preliminary noise reduction signal to remove the signal corresponding to the quasi-periodic vibration component, thereby obtaining the preprocessed tension signal.

4. The intelligent control method for a high-precision wire drawing machine based on PLC according to claim 3, characterized in that, Identifying whether there are quasi-periodic vibration components introduced by auxiliary components of the equipment in the preliminary noise reduction signal includes: Periodically extract signal segments of a preset length from the initial noise reduction signal; The signal segment is analyzed using the short-time Fourier transform algorithm to obtain the spectral distribution of the signal in the frequency domain; The energy values ​​of each frequency component in the spectrum distribution within a preset frequency range are monitored. When the energy value of any frequency component within the frequency range continuously exceeds a preset energy threshold, it is determined that the quasi-periodic vibration component exists, and the dominant frequency and amplitude of the frequency component containing the quasi-periodic vibration component are recorded.

5. The intelligent control method for a high-precision wire drawing machine based on PLC according to claim 1, characterized in that, Based on the preprocessed tension signal, trend identification is performed to determine whether there is a deviation in the true tension trend that needs to be corrected, including: Calculate the average tension deviation between the average value of the preprocessed tension signal and the preset target tension value within the second preset time window; and / or, calculate the slope of the change of the preprocessed tension signal within the second preset time window; If at least one of the following conditions is met: the average tension deviation exceeds a preset tolerance deviation, the change slope continuously deviates from zero, and the change slope continuously indicates a change rate greater than a preset rate, it is detected whether the duration of continuous satisfaction exceeds a preset duration threshold. If the duration of continuous satisfaction exceeds a preset duration threshold, it is confirmed that there is a deviation in the true tension trend.

6. The intelligent control method for a high-precision wire drawing machine based on PLC according to claim 1, characterized in that, Based on the preprocessed tension signal, trend identification is performed to determine whether there is a deviation in the true tension trend that needs to be corrected, including: Multi-dimensional trend judgment indicators are collected, including the average tension deviation calculated within a third preset time window, the stability of the slope of the average tension value calculated within multiple consecutive fourth preset time windows, the suppression degree of local fluctuation amplitude of the tension signal calculated within a fifth preset time window, and the matching degree of comparing the current tension change characteristics with a preset process change characteristic template; wherein, the length of the third preset time window is greater than the length of the fourth preset time window and the length of the fifth preset time window; the preset process change characteristic template is used to characterize the tension change trend caused by mold wear, and the higher the matching degree, the more consistent the current tension change trend is with the tension change trend caused by mold wear; The average tension deviation, stability, inhibition degree, and matching degree are weighted and calculated to obtain a confidence score that characterizes the degree of confidence in the trend. If the confidence score continues to exceed a preset score threshold within a preset confirmation period, the existence of the true tension trend deviation is confirmed.

7. The intelligent control method for a high-precision wire drawing machine based on PLC according to claim 6, characterized in that, The average tension deviation is obtained by: within the third preset time window, calculating the average value of the preprocessed tension signal, and calculating the difference between the average value and the preset target tension value, and using the difference as the average tension deviation. The stability is obtained by: calculating the slope of the change of the average value of the preprocessed tension signal within each of the multiple consecutive fourth preset time windows; if all slopes are in the same direction and the standard deviation of all slopes is lower than a preset stability threshold, the slope stability is determined to be a first preset score; if all slopes are in the same direction and / or the standard deviation of all slopes is at least partially not lower than the preset stability threshold, the slope stability is determined by discounting the first preset score based on the proportion of consistent signs and the degree of deviation of the standard deviation from the stability threshold. The suppression degree is obtained as follows: within the fifth preset time window, the running standard deviation of the preprocessed tension signal relative to the average value within the fifth preset time window is calculated. If the running standard deviation is lower than a preset suppression threshold, the value of the local fluctuation suppression degree is determined to be a second preset score. If the running standard deviation is not lower than the preset suppression threshold, the value of the local fluctuation suppression degree is determined by discounting the second preset score based on the ratio of the suppression threshold to the standard deviation. The matching degree is obtained by comparing the current trend of the preprocessed tension signal with the trend of tension change caused by mold wear in the preset process change feature template, and taking the similarity percentage obtained by comparison as the value of the matching degree.

8. The intelligent control method for a high-precision wire drawing machine based on PLC according to claim 1, characterized in that, The ideal velocity smoothing trajectory is subjected to overall velocity correction to obtain the corrected velocity trajectory, including: The correction amount is generated by a proportional-integral controller. The control cycle of the proportional-integral controller is set to be a preset multiple greater than the speed control cycle of the main tension motor. The proportional coefficient and integral coefficient of the proportional-integral controller are set to preset ratios that are less than the parameter values ​​of the traditional controller. The correction amount is gradually added to the reference speed value of the ideal speed smooth trajectory, so that the target speed of the main tension motor completes a smooth transition from the current reference speed to the corrected reference speed within a preset adjustment time, and the speed change rate during the transition is less than the preset change rate.

9. The intelligent control method for a high-precision wire drawing machine based on PLC according to claim 1, characterized in that, Generating an ideal speed smooth trajectory for the main tension motor based on the aforementioned process parameters includes: Based on the wire type, target stretching speed, stretching ratio, and at least one process parameter in the mold configuration of the metal wire to be generated, plan the speed change path of the wire from start-up to stable operation and then to stop, as the ideal speed smoothing trajectory. The ideal speed smooth trajectory includes a start-up phase, a stable operation phase, and a stopping phase; During the start-up phase, an S-shaped acceleration curve is generated by limiting the rate of change of acceleration, allowing the main tension motor speed to rise smoothly from zero to the target speed. During the stable operation phase, the speed is kept constant at the target speed. During the stopping phase, an S-shaped deceleration curve is generated by limiting the rate of change of deceleration, allowing the main tension motor speed to drop smoothly from the target speed to zero.

10. A PLC-based intelligent control system for a high-precision wire drawing machine, characterized in that, include: The planning module is used to obtain the process parameters of the metal wire to be generated, and generate the ideal speed smooth trajectory of the main stretching motor based on the process parameters. The ideal speed smooth trajectory is the smooth speed change path that the main tension motor should follow when there is no external instantaneous interference. The acquisition module is used to acquire the original tension signal of the metal wire to be generated, which is collected by the tension sensor installed on the wire drawing machine; The preprocessing module is used to preprocess the original tension signal to obtain a preprocessed tension signal; The preprocessing includes filtering out the instantaneous noise signal of the target frequency and / or the signal corresponding to the quasi-periodic vibration component in the original tension signal; The identification module is used to identify trends based on the preprocessed tension signal and determine whether there is a deviation in the true tension trend that needs to be corrected. The correction module is used to perform overall speed correction on the ideal speed smoothing trajectory at a response frequency lower than the speed control cycle of the main tension motor if there is a deviation from the actual tension trend, so as to obtain a corrected speed trajectory. The control module is used to control the operation of the main tension motor according to the corrected speed trajectory.

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