Cable eccentricity online monitoring method based on multi-point laser ranging

Abstract

The invention discloses a cable eccentricity online monitoring method based on multi-point laser ranging, and relates to the technical field of cable manufacturing and detection, and the method comprises the following steps: twelve laser displacement sensors are uniformly arranged at the periphery of a cable core to be detected, the sensors are arranged at fixed intervals of 30 degrees, and a closed annular monitoring array is formed; the method is used for synchronously acquiring radial distance data from the surface of the cable core to the inner wall of the insulating layer at each measuring point. Full-circumferential real-time monitoring is achieved through the high-density laser sensor array, the measurement precision is guaranteed through multi-algorithm fusion and temperature compensation, a closed-loop feedback control mechanism is formed in combination with production equipment, the problems of eccentricity detection blind areas, error interference and manual lag are effectively solved, and the quality consistency and production efficiency of cable manufacturing are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of cable manufacturing and detection, and in particular to an online monitoring method for cable eccentricity based on multi-point laser ranging. Background Art

[0002] "Online monitoring of cable eccentricity based on multi-point laser ranging" refers to the process of placing multiple high-precision laser displacement sensors at equal intervals around the cable's periphery during the cable production process. This allows real-time measurement of the distance data between the cable core and the insulation layer in all directions. This data is then used to calculate the concentricity (i.e., degree of eccentricity) of the cable cross section through geometric fitting and mathematical algorithms. This critical parameter is then continuously monitored online during production. This method offers the advantages of being non-contact, highly precise, and highly real-time. It can promptly detect and correct eccentricity issues without affecting the production process, thereby improving the consistency and reliability of cable products.

[0003] The existing technology has the following deficiencies: During the cable manufacturing process, the concentricity between the wire core and the insulation layer has a decisive influence on the electrical performance, safety and service life of the cable. The eccentricity phenomenon will not only lead to uneven thickness of the insulation layer, resulting in uneven distribution of the electric field, but may also create a breakdown risk in local areas, and even cause failures or accidents in severe cases. At present, the commonly used eccentricity detection methods in the industry mainly include offline sampling detection and contact mechanical measurement. Although these methods can reflect product quality to a certain extent, they have obvious defects. First, the sampling method cannot achieve full detection and is prone to missing abnormal products; second, the mechanical contact measurement method is prone to introduce human errors and has a slow response speed, which is not suitable for high-speed extrusion production lines.

[0004] Although existing non-contact detection technologies have made some progress, most still use a small number of sensors (such as 2-4) for ranging, which makes it difficult to achieve accurate monitoring in all directions, and there are problems with measurement blind spots and large deviations. At the same time, traditional systems generally lack real-time data fusion and dynamic feedback mechanisms, and are unable to adjust the extrusion process in a timely manner, resulting in problematic cables entering subsequent processes, increasing rework and material waste. In addition, external factors such as changes in ambient temperature are also prone to cause ranging errors, and the lack of effective compensation algorithms further limits the stability and application scope of the system. Therefore, there is an urgent need for a new eccentricity online monitoring system with high-density measurement points, high-precision fitting and intelligent feedback capabilities to improve cable manufacturing quality and production efficiency.

[0005] The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the Invention

[0006] The purpose of the present invention is to provide an online monitoring method for cable eccentricity based on multi-point laser ranging, which realizes full-circumferential real-time monitoring through a high-density laser sensor array, adopts multi-algorithm fusion and temperature compensation to ensure measurement accuracy, and combines with production equipment to form a closed-loop feedback control mechanism, effectively solving the problems of eccentricity detection blind spots, error interference and artificial lag, improving the quality consistency and production efficiency of cable manufacturing, and solving the problems in the above-mentioned background technology.

[0007] In order to achieve the above object, the present invention provides the following technical solution: a method for online monitoring of cable eccentricity based on multi-point laser ranging, comprising the following steps:

[0008] Twelve laser displacement sensors are evenly arranged around the outer periphery of the cable core to be tested, with a fixed interval of thirty degrees between the sensors, forming a closed ring monitoring array to synchronously collect radial distance data from the core surface to the inner wall of the insulation layer at each measuring point.

[0009] The real-time data collected by all sensors are transmitted to the host computer system through the RS-485 bus interface, and each ranging data point is converted into a two-dimensional space coordinate point in the host computer based on the conversion rule from polar coordinates to Cartesian coordinates;

[0010] The least squares algorithm is used to perform circular fitting on the twelve converted coordinate points to obtain the center position and radius of the insulation layer, and the theoretical center position of the core is independently extracted;

[0011] By comparing the spatial coordinate difference between the center of the insulation layer and the theoretical center of the core obtained by fitting, the Euclidean distance between the two is calculated, and the Euclidean distance is divided by the insulation layer radius to obtain the eccentricity value of the current cable cross section;

[0012] The calculated eccentricity value is compared with the preset threshold. When the eccentricity exceeds the limit, a feedback signal is immediately sent to the extrusion equipment, and the position of the mold or the extrusion parameters are automatically adjusted.

[0013] The eccentricity value calculated each time is recorded together with the acquisition time point, sensor coordinates, measurement raw data and temperature value to form a monitoring report. The error compensation amount of each sensor is dynamically updated based on temperature changes to ensure the long-term stability of measurement accuracy.

[0014] Preferably, the multiple laser displacement sensors are industrial-grade models with high-precision measurement and automatic adjustment of sampling frequency functions;

[0015] Each sensor is fixedly mounted on a precision-machined metal base through a standard interface. The base has excellent mechanical strength and corrosion resistance, and is suitable for long-term operation in industrial environments.

[0016] To ensure the consistency of the installation angle and horizontal position of each sensor, a standard-sized wire core is used for benchmark calibration during the initial deployment phase. Multiple rotations and data collection are used to analyze and correct the errors of each sensor, thereby establishing a compensation value during long-term use for the subsequent automatic correction of real-time ranging data.

[0017] Preferably, RS-485 data communication is completed through an industrial-grade hub that supports 16 independent downstream ports. The transmission distance between each sensor and the hub shall not exceed 1200 meters, and the unified baud rate is set to 9600bps to ensure synchronization;

[0018] Each port of the hub has 2.5kV optical isolation and 6kV lightning protection to ensure stable operation in high-noise industrial environments;

[0019] During data transmission, each frame of data is packaged in a structure with a timestamp, including the sensor number, ranging value, real-time temperature and correction parameters. No less than 20 frames are collected per second, and local average filtering is performed on the fluctuation values ​​between frames.

[0020] Preferably, the coordinate conversion process uniformly maps the measurement results into a two-dimensional spatial model based on the physical installation position of each sensor and its measured radial distance data;

[0021] Before performing this transformation, the established error compensation mechanism is applied to adjust the original measurement values ​​to improve the accuracy of the coordinate calculation;

[0022] The conversion process is the basis for subsequent circular fitting analysis. The control system has a built-in stability verification mechanism to determine whether the current conversion result meets the data integrity requirements. If key data is missing or the coordinate distribution after conversion is abnormal, the current analysis process will be interrupted and resampling will be prompted.

[0023] Preferably, the fitting calculation is performed using a data weight optimization strategy, automatically selecting the set of measurement points with the best data stability to participate in the calculation, so as to exclude extreme values ​​caused by abnormal interference from misleading the results;

[0024] During the fitting process, multiple rounds of filtering and screening mechanisms are introduced to the data of each point to ensure that the coordinate points involved in the analysis meet the preset threshold conditions for spatial distribution uniformity and measurement consistency;

[0025] After the fitting is completed, the fitting geometric parameters representing the structural characteristics of the insulation layer will be output, along with an error index reflecting the calculation credibility for use in the next stage of eccentricity judgment.

[0026] Preferably, the matching mold adjustment unit controls the position of the mold core through a precision drive mechanism, ensuring that corrective action can be taken immediately when eccentricity is detected;

[0027] When the detected eccentricity exceeds the preset control range, an adjustment instruction will be automatically sent to the control unit to drive the mold core to perform a subtle movement operation in the specified direction, and the effect changes before and after the adjustment will be tracked in real time;

[0028] If several consecutive tests show that the eccentricity error is showing a stable downward trend, it will automatically determine that an effective correction has been achieved and enter the observation mode; if the deviation fails to converge effectively, the correction state will continue until the eccentricity returns to an acceptable range.

[0029] Preferably, the eccentricity calculation is performed using the following detailed formula to ensure that the accurate cable cross-section center offset is obtained. The calculation expression is as follows:

[0030] Perform error compensation on the distance measurement value of each sensor to obtain the compensated distance. The calculation expression is as follows:

[0031] d i =r i +Δr i '

[0032] , where r i is the original distance value measured by the i-th laser displacement sensor from its position to the inner wall of the cable insulation layer, Δr i ′ is the error compensation value of the i-th laser displacement sensor, d i is the final effective ranging value of the i-th sensor;

[0033] Calculate the average value of all compensation distances as the radius of the insulation layer under ideal conditions. The calculation expression is as follows:

[0034]

[0035] , where is the distance value d measured by all laser displacement sensors i The average value of is taken as the radius of the ideal insulating layer;

[0036] The polar coordinate position of each laser displacement sensor is converted into Cartesian coordinates to establish a point set. The formula is as follows:

[0037]

[0038] , where r sensor is the installation radius of the laser sensor relative to the geometric center of the cable, θ i is the angle of the i-th laser displacement sensor to the starting point of the polar coordinate system, x i and y i Respectively represent the plane coordinates converted from the ranging results of each sensor;

[0039] The above twelve groups of point coordinates x i and y i Input the least squares circle fitting model to calculate the coordinates of the center of the insulation layer (x c ,y c );

[0040] Set the geometric center of the core to the origin (0, 0), and calculate the displacement of the insulation center relative to the core using the distance between the circle center coordinates and the origin. The calculation expression is as follows:

[0041]

[0042] , where x c and y c is the coordinate of the center of the insulation layer obtained by the least squares circle fitting algorithm, and e is the offset distance, which represents the distance from the center of the core (0, 0) to the center of the insulation layer (x c ,y c ) distance;

[0043] The offset distance e and the ideal radius Calculate the eccentricity percentage as an indicator of cable concentricity. The calculation expression is as follows:

[0044]

[0045] , where eccentricity is the eccentricity, which represents the percentage of the offset distance to the ideal radius. It is a quantitative standard for judging whether the cable meets the process requirements.

[0046] Preferably, the temperature compensation mechanism is continuously effective during the entire operation of the system, and the temperature changes around the device are recorded in real time through the built-in ambient temperature sensor device, and the measurement correction value of each sensor is dynamically updated according to the degree of temperature deviation from the predetermined calibration state;

[0047] All compensation operations are completed automatically before data collection without manual intervention, effectively eliminating the impact of temperature changes on ranging accuracy and ensuring that the entire monitoring system always maintains stable and reliable measurement performance under different environmental conditions.

[0048] Preferably, the fitting error and the stability of the monitoring system are judged by the following steps to ensure that the monitoring system continues to operate within the precision control range. The specific steps are as follows:

[0049] The center of the circle (x c ,y c ) and each sensor coordinate point (x i ,y i) to calculate the fitting error between them, find the deviation value of each point, and sum the squares to get the total residual sum of squares. The calculation expression is as follows:

[0050]

[0051] , where S is the total residual sum of squares;

[0052] The total residual sum of squares S is converted into the root mean square error to evaluate the overall fitting accuracy. The calculation expression is as follows:

[0053]

[0054] , where RMSE is the root mean square error;

[0055] When the RMSE is lower than the set accuracy threshold ∈ 1, the monitoring system is considered to be in a stable operating state;

[0056] If the RMSE calculated by the system for three consecutive samplings exceeds the preset maximum fluctuation value ΔRMSE max , the recalibration process is automatically triggered to prevent long-term accumulation of errors from affecting accuracy.

[0057] In the above technical solution, the technical effects and advantages provided by the present invention are:

[0058] This invention utilizes a high-density laser sensor array to achieve full-circumferential, non-contact, real-time monitoring of cable eccentricity. Compared to traditional offline spot checks or infrequent sampling methods, this system continuously and comprehensively acquires geometric deviation information from the insulation layer during the cable extrusion process, effectively avoiding the omission of measurement blind spots and local anomalies. By continuously scanning and reconstructing coordinates across the entire cross-section, cable geometric quality control has evolved from intermittent manual judgment to a data-driven, continuous monitoring mode, significantly improving detection coverage and response speed.

[0059] This invention ensures high accuracy and stability of monitoring data by introducing error compensation, coordinate transformation, and multi-algorithm fusion mechanisms. The system is capable of dynamic correction based on historical sensor fluctuation data. Combined with a temperature compensation model, it effectively addresses the interference of industrial field environmental factors on measurement accuracy. The circular fitting algorithm utilizes a multi-point redundancy optimization mechanism to filter out local outliers, thereby maintaining a high degree of reliability in monitoring results. By comprehensively optimizing hardware design and data processing processes, the system can operate stably and long-term on high-speed production lines, providing reliable technical support for high-grade cable manufacturing.

[0060] Through a linkage control mechanism with production equipment, this invention enables automatic feedback adjustment and real-time process correction for abnormal eccentricity. When the system detects that the eccentricity exceeds a set threshold, it immediately drives the control unit to perform mold adjustment operations, dynamically correcting extrusion process parameters and effectively suppressing the production of defective products. This closed-loop control mechanism not only avoids delays caused by human intervention but also significantly reduces raw material waste and equipment load, enabling intelligent optimization of the manufacturing process. Ultimately, this improves the overall consistency and yield rate of the cable, while reducing the burden of subsequent rework and quality inspection, thereby enhancing production efficiency and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction to the drawings required for use in the embodiments will be given below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0062] Figure 1 The present invention is a flow chart of a method for online monitoring of cable eccentricity based on multi-point laser ranging. DETAILED DESCRIPTION

[0063] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these example embodiments are provided so that the description of this disclosure will be thorough and complete and will fully convey the concepts of the example embodiments to those skilled in the art.

[0064] The present invention provides Figure 1 The cable eccentricity online monitoring method based on multi-point laser ranging shown includes the following steps:

[0065] Twelve laser displacement sensors are evenly arranged around the outer periphery of the cable core to be tested, with a fixed interval of thirty degrees between the sensors, forming a closed ring monitoring array to synchronously collect radial distance data from the core surface to the inner wall of the insulation layer at each measuring point.

[0066] Multiple laser displacement sensors are industrial-grade models with high-precision measurement and automatic adjustment of sampling frequency;

[0067] Each sensor is fixedly mounted on a precision-machined metal base through a standard interface. The base has excellent mechanical strength and corrosion resistance, and is suitable for long-term operation in industrial environments.

[0068] To ensure the consistency of the installation angle and horizontal position of each sensor, a standard-sized wire core is used for benchmark calibration during the initial deployment phase. Multiple rotations and data collection are used to analyze and correct the errors of each sensor, thereby establishing a compensation value during long-term use for the subsequent automatic correction of real-time ranging data.

[0069] The real-time data collected by all sensors are transmitted to the host computer system through the RS-485 bus interface, and each ranging data point is converted into a two-dimensional space coordinate point in the host computer based on the conversion rule from polar coordinates to Cartesian coordinates;

[0070] RS-485 data communication is completed through an industrial-grade hub that supports 16 independent downstream ports. The transmission distance between each sensor and the hub shall not exceed 1200 meters, and the unified baud rate is set to 9600bps to ensure synchronization;

[0071] Each port of the hub has 2.5kV optical isolation and 6kV lightning protection to ensure stable operation in high-noise industrial environments;

[0072] During data transmission, each frame of data is packaged in a structure with a timestamp, including the sensor number, ranging value, real-time temperature and correction parameters. No less than 20 frames are collected per second, and local average filtering is performed on the fluctuation values ​​between frames.

[0073] The least squares algorithm is used to perform circular fitting on the twelve converted coordinate points to obtain the center position and radius of the insulation layer, and the theoretical center position of the core is independently extracted;

[0074] The coordinate transformation process maps the measurement results into a two-dimensional spatial model based on the physical installation position of each sensor and its measured radial distance data;

[0075] Before performing this transformation, the established error compensation mechanism is applied to adjust the original measurement values ​​to improve the accuracy of the coordinate calculation;

[0076] The conversion process is the basis for subsequent circular fitting analysis. The control system has a built-in stability verification mechanism to determine whether the current conversion result meets the data integrity requirements. If key data is missing or the coordinate distribution after conversion is abnormal, the current analysis process will be interrupted and resampling will be prompted.

[0077] The fitting calculation adopts the data weight optimization strategy to automatically select the measurement point set with the best data stability to participate in the calculation, so as to eliminate the extreme values ​​caused by abnormal interference that may mislead the results.

[0078] During the fitting process, multiple rounds of filtering and screening mechanisms are introduced to the data of each point to ensure that the coordinate points involved in the analysis meet the preset threshold conditions for spatial distribution uniformity and measurement consistency;

[0079] After the fitting is completed, the fitting geometric parameters representing the structural characteristics of the insulation layer will be output, along with an error index reflecting the calculation credibility for use in the next stage of eccentricity judgment.

[0080] By comparing the spatial coordinate difference between the center of the insulation layer and the theoretical center of the core obtained by fitting, the Euclidean distance between the two is calculated, and the Euclidean distance is divided by the insulation layer radius to obtain the eccentricity value of the current cable cross section;

[0081] The matching mold adjustment unit controls the position of the mold core through a precision drive mechanism, ensuring that corrective action can be taken immediately when eccentricity is detected;

[0082] When the detected eccentricity exceeds the preset control range, an adjustment instruction will be automatically sent to the control unit to drive the mold core to perform a subtle movement operation in the specified direction, and the effect changes before and after the adjustment will be tracked in real time;

[0083] If several consecutive tests show that the eccentricity error is showing a stable downward trend, it will automatically determine that an effective correction has been achieved and enter the observation mode; if the deviation fails to converge effectively, the correction state will continue until the eccentricity returns to an acceptable range.

[0084] The calculated eccentricity value is compared with the preset threshold. When the eccentricity exceeds the limit, a feedback signal is immediately sent to the extrusion equipment, and the position of the mold or the extrusion parameters are automatically adjusted.

[0085] The eccentricity calculation is performed using the following detailed formula to ensure accurate cable cross-section center offset. The calculation expression is as follows:

[0086] Perform error compensation on the distance measurement value of each sensor to obtain the compensated distance. The calculation expression is as follows:

[0087] d i =r i +Δr i '

[0088] , where r i is the original distance value measured by the i-th laser displacement sensor from its position to the inner wall of the cable insulation layer, Δr i ′ is the error compensation value of the i-th laser displacement sensor, which has been corrected according to the installation deviation and temperature drift, d i is the final effective ranging value of the i-th sensor;

[0089] This step is used to eliminate the effects of installation errors and temperature drift.

[0090] Calculate the average value of all compensation distances as the radius of the insulation layer under ideal conditions. The calculation expression is as follows:

[0091]

[0092] , where is the distance value d measured by all laser displacement sensors i The average value of is taken as the radius of the ideal insulating layer;

[0093] The polar coordinate position of each laser displacement sensor is converted into Cartesian coordinates to establish a point set. The formula is as follows:

[0094]

[0095] , where r sensor The installation radius of the laser sensor relative to the geometric center of the cable, that is, the ideal distance when the sensor is fixedly installed, is used to determine the reference radius of the sensor in the polar coordinate system for coordinate conversion, θ i is the angle of the i-th laser displacement sensor to the starting point of the polar coordinate system, x i and y i Respectively represent the plane coordinates converted from the ranging results of each sensor, which are used to form the two-dimensional coordinates of the circle fitting point set and used to calculate the center position of the insulation layer;

[0096] The above twelve groups of point coordinates x i and y i Input the least squares circle fitting model to calculate the coordinates of the center of the insulation layer (x c ,y c );

[0097] Set the geometric center of the core to the origin (0, 0), and calculate the displacement of the insulation center relative to the core using the distance between the circle center coordinates and the origin. The calculation expression is as follows:

[0098]

[0099] , where x c and y c is the coordinate of the center of the insulation layer obtained by the least squares circle fitting algorithm, and e is the offset distance, which represents the distance from the center of the core (0, 0) to the center of the insulation layer (x c ,y c ) distance;

[0100] The offset distance e and the ideal radius Calculate the eccentricity percentage as an indicator of cable concentricity. The calculation expression is as follows:

[0101]

[0102] , where eccentricity is the eccentricity, which represents the percentage of the offset distance to the ideal radius. It is a quantitative standard for judging whether the cable meets the process requirements.

[0103] The eccentricity value calculated each time is recorded together with the acquisition time point, sensor coordinates, measurement raw data and temperature value to form a monitoring report. The error compensation amount of each sensor is dynamically updated based on temperature changes to ensure the long-term stability of measurement accuracy.

[0104] The temperature compensation mechanism is continuously effective during the entire system operation process. The built-in ambient temperature sensor records the temperature changes around the equipment in real time and dynamically updates the measurement correction value of each sensor according to the degree of temperature deviation from the predetermined calibration state.

[0105] All compensation operations are completed automatically before data collection without manual intervention, effectively eliminating the impact of temperature changes on ranging accuracy and ensuring that the entire monitoring system always maintains stable and reliable measurement performance under different environmental conditions.

[0106] The fitting error and monitoring system stability are judged through the following steps to ensure that the monitoring system continues to operate within the accuracy control range. The specific steps are as follows:

[0107] The center of the circle (x c ,y c ) and each sensor coordinate point (x i ,y i ) to calculate the fitting error between them, find the deviation value of each point, and sum the squares to get the total residual sum of squares. The calculation expression is as follows:

[0108]

[0109] , where S is the total residual sum of squares;

[0110] The total residual sum of squares S is converted into the root mean square error to evaluate the overall fitting accuracy. The calculation expression is as follows:

[0111]

[0112] , where RMSE is the root mean square error, which is used to measure the average deviation between the 12 measurement points and the fitting circle. The smaller the RMSE, the more ideal the fitting effect, indicating that the monitoring system has higher accuracy;

[0113] When the RMSE is lower than the set accuracy threshold ∈ 1, the monitoring system is considered to be in a stable operating state;

[0114] If the RMSE calculated by the system for three consecutive samplings exceeds the preset maximum fluctuation value ΔRMSE max , the recalibration process is automatically triggered to prevent long-term accumulation of errors from affecting accuracy.

[0115] Implementation method one: In the actual deployment scenario of the cable production line, the monitoring system is mainly used between the insulation layer extrusion stage and the cooling and molding area. This position can not only ensure that the measurement data reflects the actual insulation molding state, but also have sufficient reaction time to make process adjustments after the eccentricity anomaly is discovered. The system deployment first uses a precision-machined CNC metal structure as the mounting base. Its design meets the standard outer diameter range of industrial cables and has good mechanical strength and high temperature resistance. Twelve high-precision laser displacement sensors are fixed to the base at equal intervals through preset screw holes, forming a complete circular structure at intervals of 30 degrees, and constructing a coaxial monitoring ring around the cable core.

[0116] Each sensor is connected to a data acquisition module via an M12 interface, which is then connected to an industrial-grade RS-485 hub. The hub features industrial-grade features such as anti-interference, lightning protection, and isolation, and can operate stably in environments with high dust, strong vibration, and electromagnetic noise. All data is ultimately fed into a host computer for unified processing. The operator can use the host computer software to set system parameters, read measurement data, perform error calibration, and output reports. After the initial installation is complete, the system guides the user through initial calibration: install a standard circular wire core, pass it through the center of the monitoring loop, and hold it stationary in front of each sensor. At this point, the system collects the raw distance values ​​of the twelve sensors and, by comparing their geometric symmetry with the known theoretical radius, automatically calculates the angular deviation and ranging error incurred by each sensor during installation.

[0117] The calibration process also includes multi-angle rotation testing. While the standard cable core remains stationary, the entire system is rotated three times, sampling at 0°, 90°, and 180° to verify measurement consistency. The system uses the differential data from these rotation samples to further refine the precise compensation value for each sensor and stores it in a local database as a constant parameter for all subsequent distance corrections. Once sensor compensation is complete, the system enters formal online monitoring, collecting real-time data from every cable section during production. It's worth noting that all electrical connections are encapsulated in a high-temperature flexible sheath and use shielded cables to resist interference, ensuring stable and continuous data transmission. Throughout the system's deployment phase, consideration was given to both structural rigidity and measurement accuracy, while also providing ample flexibility for future maintenance and expansion.

[0118] Implementation Method 2: After the sensor completes real-time ranging and transmits the raw data to the data processing unit, the system first performs preliminary cleaning on all input data. This includes checking for data anomalies such as transient frame drops, breakpoints, and jumps. Specifically, to address measurement fluctuations caused by oil contamination, changes in light spot reflectivity, and wire core deflection, which can occur in industrial production, the system includes a filtering module that combines sliding window averaging, standard deviation control, and median filtering to suppress noise and eliminate sudden changes.

[0119] After compensation, the data points corresponding to each laser sensor undergo coordinate conversion. Because the sensors are symmetrically distributed around a circle, the system pre-stores the polar angle and installation radius of each sensor. By converting the polar coordinate data to Cartesian coordinates, the system successfully constructs twelve two-dimensional spatial points on the cross section for subsequent geometric fitting.

[0120] The fitting process is the core of the entire algorithm. The system uses weighted least squares for circle fitting and incorporates a mechanism for evaluating the credibility of fitting points. If the error fluctuation of a particular sensor is large within a recent statistical window, the corresponding data will be assigned a lower weight, or even completely eliminated if it reaches the set error threshold. This prevents local errors from affecting the overall model accuracy. During the fitting process, the current residual, circle center drift, and fitting radius change are calculated and dynamically compared with the previous fitting result to determine whether there are any stability issues.

[0121] To address unexpected situations that could affect accuracy, such as sudden structural irregularities or material deformation, the system has a fallback mechanism. If the current fitting error exceeds the threshold three or more times in a row, the system suspends eccentricity output and resamples and recalculates data until stability is restored. This prevents misleading product quality judgments from being affected by a single outlier. Furthermore, the system stores all intermediate fitting data along with each set of original sensor distance measurements, creating a traceable and retrievable monitoring record system. This facilitates subsequent technical review of anomalies and the formulation of process adjustment recommendations.

[0122] Implementation Method 3: This implementation method focuses on integrating real-time monitoring results with the cable extrusion equipment's process control system to establish a complete closed-loop control logic. The eccentricity calculation module outputs an updated value every second and compares it with the system's preset tolerance range. If the current eccentricity value exceeds a warning level (e.g., 5% or 3% for different cable types), the system immediately invokes a control interface and sends an adjustment command to the PLC.

[0123] Extrusion equipment mold adjustment modules typically utilize an electric stepper mechanism, which adjusts the relative position between the die and the wire core in minute increments. During the feedback adjustment process, the system also monitors the trend of the adjusted values ​​to determine whether convergence has been achieved. If the eccentricity decreases three times in a row, indicating the adjustment direction and magnitude are correct, the current adjustment cycle is maintained. If there is no improvement or the eccentricity increases in the opposite direction, the system automatically adjusts the strategy or recommends manual intervention.

[0124] Furthermore, the system supports flexible adjustments to feedback frequency and intervention strategies to accommodate different production cycles. For example, in high-speed extrusion processes, the system can increase the data refresh rate and adjustment frequency; in medium- and low-speed scenarios, it can be set to timed sampling and slow adjustments to prevent excessive process fluctuations. All adjustment data is automatically archived through an event logging system, including key parameters such as adjustment initiation time, adjustment value, response delay, and resulting eccentricity change, ensuring a high degree of transparency and analytical value for the entire closed-loop system.

[0125] In abnormal situations, such as when multiple sensors fail simultaneously or when system errors suddenly increase, the system triggers safety logic, suspends adjustments, and issues an alarm to prevent secondary deviations caused by misjudgments. Furthermore, this mechanism supports integration with the MES production management system, enabling functions such as uploading test results, coordinated equipment control, and statistical analysis of quality trends, gradually building a core sensing unit in intelligent manufacturing. This feedback linkage mechanism not only significantly improves the qualified rate of finished cables, but also plays a vital role in energy conservation and material control, providing effective support for intelligent and automated modern cable manufacturing.

[0126] This invention utilizes a high-density laser sensor array to achieve full-circumferential, non-contact, real-time monitoring of cable eccentricity. Compared to traditional offline spot checks or infrequent sampling methods, this system continuously and comprehensively acquires geometric deviation information from the insulation layer during the cable extrusion process, effectively avoiding the omission of measurement blind spots and local anomalies. By continuously scanning and reconstructing coordinates across the entire cross-section, cable geometric quality control has evolved from intermittent manual judgment to a data-driven, continuous monitoring mode, significantly improving detection coverage and response speed.

[0127] This invention ensures high accuracy and stability of monitoring data by introducing error compensation, coordinate transformation, and multi-algorithm fusion mechanisms. The system is capable of dynamic correction based on historical sensor fluctuation data. Combined with a temperature compensation model, it effectively addresses the interference of industrial field environmental factors on measurement accuracy. The circular fitting algorithm utilizes a multi-point redundancy optimization mechanism to filter out local outliers, thereby maintaining a high degree of reliability in monitoring results. By comprehensively optimizing hardware design and data processing processes, the system can operate stably and long-term on high-speed production lines, providing reliable technical support for high-grade cable manufacturing.

[0128] Through a linkage control mechanism with production equipment, this invention enables automatic feedback adjustment and real-time process correction for abnormal eccentricity. When the system detects that the eccentricity exceeds a set threshold, it immediately drives the control unit to perform mold adjustment operations, dynamically correcting extrusion process parameters and effectively suppressing the production of defective products. This closed-loop control mechanism not only avoids delays caused by human intervention but also significantly reduces raw material waste and equipment load, enabling intelligent optimization of the manufacturing process. Ultimately, this improves the overall consistency and yield rate of the cable, while reducing the burden of subsequent rework and quality inspection, thereby enhancing production efficiency and economic benefits.

[0129] The above formulas are all dimensionless and numerical calculations. The formulas are obtained by collecting a large amount of data and performing software simulation to obtain the most recent real situation. The preset parameters in the formulas are set by technicians in this field according to actual conditions.

[0130] The above description is merely illustrative of certain exemplary embodiments of the present invention. It goes without saying that those skilled in the art will be able to modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and description are illustrative in nature and should not be construed as limiting the scope of protection of the claims.

[0131] It should be noted that, in this document, if there are relational terms such as first and second, etc., they are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device that includes the element.

[0132] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0133] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0134] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0135] The units described as separate components may or may not be physically separate, and 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 these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0136] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0137] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

[0138] The above description is merely illustrative of certain exemplary embodiments of the present invention. It goes without saying that those skilled in the art will be able to modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and description are illustrative in nature and should not be construed as limiting the scope of protection of the claims.

Claims

1. The cable eccentricity online monitoring method based on multi-point laser ranging is characterized by: The following steps are involved: Twelve laser displacement sensors are evenly arranged around the outer periphery of the cable core to be tested, with a fixed interval of thirty degrees between the sensors, forming a closed ring monitoring array to synchronously collect radial distance data from the core surface to the inner wall of the insulation layer at each measuring point. The real-time data collected by all sensors are transmitted to the host computer system through the RS-485 bus interface, and each ranging data point is converted into a two-dimensional space coordinate point in the host computer based on the conversion rule from polar coordinates to Cartesian coordinates; The least squares algorithm is used to perform circular fitting on the twelve converted coordinate points to obtain the center position and radius of the insulation layer, and the theoretical center position of the core is independently extracted; By comparing the spatial coordinate difference between the center of the insulation layer and the theoretical center of the core obtained by fitting, the Euclidean distance between the two is calculated, and the Euclidean distance is divided by the insulation layer radius to obtain the eccentricity value of the current cable cross section; The calculated eccentricity value is compared with the preset threshold. When the eccentricity exceeds the limit, a feedback signal is immediately sent to the extrusion equipment, and the position of the mold or the extrusion parameters are automatically adjusted. The eccentricity value calculated each time is recorded together with the acquisition time point, sensor coordinates, measurement raw data and temperature value to form a monitoring report. The error compensation amount of each sensor is dynamically updated based on temperature changes to ensure the long-term stability of measurement accuracy.

2. The method for online monitoring of cable eccentricity based on multi-point laser ranging according to claim 1, characterized in that: Multiple laser displacement sensors are industrial-grade models with high-precision measurement and automatic adjustment of sampling frequency; Each sensor is fixedly mounted on a precision-machined metal base through a standard interface. The base has excellent mechanical strength and corrosion resistance, and is suitable for long-term operation in industrial environments. To ensure the consistency of the installation angle and horizontal position of each sensor, a standard-sized wire core is used for benchmark calibration during the initial deployment phase. Multiple rotations and data collection are used to analyze and correct the errors of each sensor, thereby establishing a compensation value during long-term use for the subsequent automatic correction of real-time ranging data.

3. The method for online monitoring of cable eccentricity based on multi-point laser ranging according to claim 1, characterized in that: RS-485 data communication is completed through an industrial-grade hub that supports 16 independent downstream ports. The transmission distance between each sensor and the hub shall not exceed 1200 meters, and the unified baud rate is set to 9600bps to ensure synchronization; Each port of the hub has 2.5kV optical isolation and 6kV lightning protection to ensure stable operation in high-noise industrial environments; During data transmission, each frame of data is packaged in a structure with a timestamp, including the sensor number, ranging value, real-time temperature and correction parameters. No less than 20 frames are collected per second, and local average filtering is performed on the fluctuation values ​​between frames.

4. The method for online monitoring of cable eccentricity based on multi-point laser ranging according to claim 1, characterized in that: The coordinate transformation process maps the measurement results into a two-dimensional spatial model based on the physical installation position of each sensor and its measured radial distance data; Before performing this transformation, the established error compensation mechanism is applied to adjust the original measurement values ​​to improve the accuracy of the coordinate calculation; The conversion process is the basis for subsequent circular fitting analysis. The control system has a built-in stability verification mechanism to determine whether the current conversion result meets the data integrity requirements. If key data is missing or the coordinate distribution after conversion is abnormal, the current analysis process will be interrupted and resampling will be prompted.

5. The method for online monitoring of cable eccentricity based on multi-point laser ranging according to claim 1, characterized in that: The fitting calculation adopts the data weight optimization strategy to automatically select the measurement point set with the best data stability to participate in the calculation, so as to eliminate the extreme values ​​caused by abnormal interference that may mislead the results. During the fitting process, multiple rounds of filtering and screening mechanisms are introduced to the data of each point to ensure that the coordinate points involved in the analysis meet the preset threshold conditions for spatial distribution uniformity and measurement consistency; After the fitting is completed, the fitting geometric parameters representing the structural characteristics of the insulation layer will be output, along with an error index reflecting the calculation credibility for use in the next stage of eccentricity judgment.

6. The method for online monitoring of cable eccentricity based on multi-point laser ranging according to claim 1, characterized in that: The matching mold adjustment unit controls the position of the mold core through a precision drive mechanism, ensuring that corrective action can be taken immediately when eccentricity is detected; When the detected eccentricity exceeds the preset control range, an adjustment instruction will be automatically sent to the control unit to drive the mold core to perform a subtle movement operation in the specified direction, and the effect changes before and after the adjustment will be tracked in real time; If several consecutive tests show that the eccentricity error is showing a stable downward trend, it will automatically determine that an effective correction has been achieved and enter the observation mode; If the deviation fails to converge effectively, the correction state will continue until the eccentricity returns to an acceptable range.

7. The method for online monitoring of cable eccentricity based on multi-point laser ranging according to claim 1, characterized in that: The eccentricity calculation is performed using the following detailed formula to ensure accurate cable cross-section center offset. The calculation expression is as follows: Perform error compensation on the distance measurement value of each sensor to obtain the compensated distance. The calculation expression is as follows: d i =r i +Δr i ', where r i is the original distance value measured by the i-th laser displacement sensor from its position to the inner wall of the cable insulation layer, Δr i ′ is the error compensation value of the i-th laser displacement sensor, d i is the final effective ranging value of the i-th sensor; Calculate the average value of all compensation distances as the radius of the insulation layer under ideal conditions. The calculation expression is as follows: , where is the distance value d measured by all laser displacement sensors i The average value of is taken as the radius of the ideal insulating layer; The polar coordinate position of each laser displacement sensor is converted into Cartesian coordinates to establish a point set. The formula is as follows: , where r sensor is the installation radius of the laser sensor relative to the geometric center of the cable, θ i is the angle of the i-th laser displacement sensor to the starting point of the polar coordinate system, x i and y i Respectively represent the plane coordinates converted from the ranging results of each sensor; The above twelve groups of point coordinates x i and y i Input the least squares circle fitting model to calculate the coordinates of the center of the insulation layer (x c ,y c ); Set the geometric center of the core to the origin (0, 0), and calculate the displacement of the insulation center relative to the core using the distance between the circle center coordinates and the origin. The calculation expression is as follows: , where x c and y c is the coordinate of the center of the insulation layer obtained by the least squares circle fitting algorithm, and e is the offset distance, which represents the distance from the center of the core (0, 0) to the center of the insulation layer (x c ,y c ) distance; The offset distance e and the ideal radius Calculate the eccentricity percentage as an indicator of cable concentricity. The calculation expression is as follows: , where eccentricity is the eccentricity, which represents the percentage of the offset distance to the ideal radius. It is a quantitative standard for judging whether the cable meets the process requirements.

8. The method for online monitoring of cable eccentricity based on multi-point laser ranging according to claim 1, characterized in that: The temperature compensation mechanism is continuously effective during the entire system operation process. The built-in ambient temperature sensor records the temperature changes around the equipment in real time and dynamically updates the measurement correction value of each sensor according to the degree of temperature deviation from the predetermined calibration state. All compensation operations are completed automatically before data collection without manual intervention, effectively eliminating the impact of temperature changes on ranging accuracy and ensuring that the entire monitoring system always maintains stable and reliable measurement performance under different environmental conditions.

9. The method for online monitoring of cable eccentricity based on multi-point laser ranging according to claim 1, characterized in that: The fitting error and monitoring system stability are judged through the following steps to ensure that the monitoring system continues to operate within the accuracy control range. The specific steps are as follows: The center of the circle (x c ,y c ) and each sensor coordinate point (x i ,y i ) to calculate the fitting error between them, find the deviation value of each point, and sum the squares to get the total residual sum of squares. The calculation expression is as follows: , where S is the total residual sum of squares; The total residual sum of squares S is converted into the root mean square error to evaluate the overall fitting accuracy. The calculation expression is as follows: , where RMSE is the root mean square error; When the RMSE is lower than the set accuracy threshold ∈ 1, the monitoring system is considered to be in a stable operating state; If the RMSE calculated by the system for three consecutive samplings exceeds the preset maximum fluctuation value ΔRMSE max , the recalibration process is automatically triggered to prevent long-term accumulation of errors from affecting accuracy.

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