Heating pad quality abnormity identification method based on full-process management and control

Abstract

The invention discloses a heating pad quality abnormity identification method based on full-process management and control, and relates to the technical field of automobile heating pad quality detection.The method comprises the steps that when a heating pad is not powered on, a multi-frequency micro-voltage signal and a high-frequency narrow-pulse voltage signal are applied to collect real-time data, a line structure integrity factor is calculated and compared with a threshold value, and the quality abnormity of the heating pad is identified; judging the qualification of the electrical structure; constant-power heating is applied to the qualified sample piece, a hot wire and surface temperature sequence is collected in real time, a temperature consistency index is calculated and compared with a threshold value, and thermal inertia and temperature consistency are judged; periodic mechanical stress is loaded on the qualified sample, mechanical stress and resistance change are collected in real time, a stress resistance lag coefficient is calculated and compared with a threshold value, and the mechanical fatigue hidden danger risk is evaluated; various unqualified labels and key process parameters are extracted, traceability analysis is carried out, a correction model is constructed, abnormal process parameters are corrected, a production correction strategy is automatically generated, and accurate detection and process optimization of the quality of the heating pad are achieved.

Description

Technical Field

[0001] This invention relates to the field of automotive heating pad quality inspection technology, specifically a heating pad quality anomaly identification method based on full-process control. Background Technology

[0002] With the increasing demand for automotive comfort, heated car seats have become an important feature in modern vehicles. As a key component, the performance and reliability of the seat heating pad directly impact user experience and overall vehicle quality. Traditional heating pad resistance testing relies primarily on single resistance value measurements, which are insufficient to accurately reflect performance degradation and potential malfunctions caused by material aging, mechanical stress, and manufacturing defects during actual use.

[0003] Furthermore, existing testing methods typically lack comprehensive multi-dimensional and multi-parameter assessments, failing to achieve full monitoring of the electrical and mechanical condition of heating pads. This makes it difficult to accurately identify potential problems and guide production process improvements. With the development of intelligent manufacturing and industrial IoT technologies, there is an urgent need for an intelligent testing system capable of real-time, multi-frequency, and multi-parameter data acquisition and analysis. This system would enable comprehensive health assessments of heating pads, from electrical characteristics to mechanical fatigue, improving testing accuracy and production efficiency, and facilitating defect traceability and closed-loop management. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for identifying abnormal heating pad quality based on full-process control, in order to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a heating pad quality anomaly identification method based on full-process control, comprising the following steps:

[0006] Step 1: With the car heating pad de-energized, apply a preset multi-frequency micro-voltage signal to the heating wire circuit and collect the impedance amplitude Zf and phase angle at each frequency point. The impedance spectrum shift index (ISI) was calculated and obtained. A high-frequency narrow pulse voltage signal was applied to the power input terminal of the same heating pad, and the transient voltage echo waveform (Vecho), the input pulse voltage waveform (Vin), the reference voltage (Vbase), and the transient echo voltage were acquired. Calculate and obtain the echo reflection coefficient Rb; further calculate and obtain the line structure integrity factor Gimp, and compare and analyze it with the impedance spectrum offset index ISI, the line structure integrity threshold Gth, and the impedance spectrum offset tolerance threshold Ith to determine whether the original electrical structure of the heating pad is qualified. If it is qualified, proceed to step two; if it is not qualified, mark the label and enter the traceability stage.

[0007] Step 2: Apply constant power to the heating pad sample with qualified original electrical structure for heating; collect the time series of temperature values ​​TW(t) of the hot wire temperature rise curve and the spatial distribution time series of the heating pad surface temperature in real time. Calculate and obtain the temperature consistency index (TCI), and compare it with the temperature consistency threshold (Tth) to determine whether the thermal inertia and temperature consistency of the heating pad are qualified. If qualified, proceed to step three; if not qualified, mark the label and enter the traceability stage.

[0008] Step 3: For heating pad samples with qualified thermal inertia and temperature consistency, a periodic mechanical stress test is applied by the loading device under heating conditions. The mechanical stress change curve and the heating pad resistance change curve are collected in real time. The stress resistance hysteresis coefficient SDI is calculated and compared with the mechanical fatigue hysteresis threshold Sth to determine whether there is a risk of mechanical fatigue. If there is a risk, a label is marked and the product enters the traceability stage.

[0009] Step 4: By extracting original electrical structure non-conformance labels, temperature consistency non-conformance labels, and mechanical fatigue potential risk labels, and combining them with production batches and key process parameters, trace the key processes and links that are non-conforming; construct a correction data model based on the traceability results and abnormal indicators, and correct abnormal process parameters in combination with standard parameters to update process data; automatically generate targeted production correction strategies.

[0010] Preferably, step one includes:

[0011] S11. With the automotive heating pad de-energized, a preset multi-frequency micro-voltage signal is applied to the heating wire circuit using precision impedance analysis. The impedance amplitude Zf and phase angle at each frequency point are collected by an impedance measuring device mounted on the test fixture. ;

[0012] S12, through impedance amplitude Zf and phase angle Using spectral fitting calculation techniques, after dimensionless processing, the distributed capacitance value Cf and the distributed inductance value Lf are calculated and obtained.

[0013] S13. Perform median filtering on the impedance amplitude Zf, distributed capacitance Cf, and distributed inductance Lf corresponding to the frequency point to remove random noise and occasional abnormal data during the measurement process, thereby improving the continuity and smoothness of the parameter curve.

[0014] S14. Compare and analyze the impedance amplitude Zf, distributed capacitance Cf, and distributed inductance Lf curves with the pre-established standard curve data of good products; obtain the impedance spectrum shift index ISI based on the deviation of the impedance amplitude.

[0015] Preferably, step one also includes:

[0016] S15. Apply a high-frequency narrow-pulse voltage signal to the power input terminal of the same heating pad. Acquire the transient voltage echo waveform Vecho and the input pulse voltage waveform Vin using a high-bandwidth oscilloscope connected to the heating pad, and simultaneously acquire the reference voltage Vbase. At the time tref when the echo signal first appears, acquire the transient echo voltage. ;

[0017] S16. The transient voltage echo waveform Vecho, the input pulse voltage waveform Vin, and the transient echo voltage are acquired through data collection. After dimensionless processing, the echo reflection coefficient Rb is calculated using the time-domain reflectometry method.

[0018] Preferably, step one also includes:

[0019] S17. By obtaining the impedance spectrum shift index ISI and the echo reflection coefficient Rb, and after dimensionless processing, the line structure integrity factor Gimp is obtained through comprehensive calculation.

[0020] S18. By setting a line structure integrity threshold Gth and an impedance spectrum shift tolerance threshold Ith, and comparing the line structure integrity factor Gimp and the impedance spectrum shift index II with the line structure integrity threshold Gth and the impedance spectrum shift tolerance threshold Ith, the first evaluation results are obtained, including:

[0021] When the line structure integrity factor Gimp ≥ the line structure integrity threshold Gth, and the impedance spectrum offset index ISI < the impedance spectrum offset tolerance threshold Ith, it indicates that the original electrical structure of the heating pad is qualified, and proceed to step two.

[0022] When any one of the following conditions is not met: the line structure integrity factor Gimp ≥ the line structure integrity threshold Gth, and the impedance spectrum offset index ISI < the impedance spectrum offset tolerance threshold Ith, it indicates that the original electrical structure of the heating pad is unqualified, triggering the first warning instruction, marking the current heating pad with the original electrical structure unqualified label, and entering the traceability stage.

[0023] Preferably, step two includes:

[0024] S21. For heating pad samples with qualified original electrical structure, apply constant power for heating without damaging their structural integrity.

[0025] S22. Obtain the time series of temperature values ​​TW(t) of the heating wire temperature rise curve using the temperature sensor on the heating wire; obtain the time series of spatial distribution of surface temperature of the heating pad using the installed surface temperature sensor array. .

[0026] Preferably, step two also includes:

[0027] S23. The time series of temperature values ​​TW(t) from the hot wire temperature rise curve and the time series of spatial distribution of the heating pad surface temperature. After dimensionless processing, the temperature uniformity index (TCI) is calculated and obtained.

[0028] S24. By setting a preset temperature consistency threshold Tth, and comparing the temperature consistency index TCI with the temperature consistency threshold Tth, the second evaluation results are obtained, including:

[0029] When the temperature consistency index TCI is greater than or equal to the temperature consistency threshold Tth, it indicates that the heating pad's thermal inertia and temperature consistency are qualified, and proceed to step three;

[0030] When the temperature consistency index TCI is less than the temperature consistency threshold Tth, it indicates that the heating pad's thermal inertia and temperature consistency are unqualified, triggering a second warning instruction to mark the current heating pad with a temperature consistency unqualified label and enter the traceability stage.

[0031] Preferably, step three includes:

[0032] S31. For heating pad samples with qualified thermal inertia and temperature consistency, a periodic mechanical stress test is applied by the loading device under heating conditions, with the period set as Tp.

[0033] S32. The mechanical stress is measured in real time by a miniature force sensor and converted into stress value by a signal conditioning module to obtain the curve of mechanical stress changing over time; the resistance of the heating pad is measured in real time by a four-terminal resistance measuring device and synchronously recorded by a data acquisition card DAQ to obtain the curve of heating pad resistance changing over time.

[0034] S33. The mechanical stress versus time curve and the heating pad resistance versus time curve are aligned using synchronous sampling; the resulting sequence is denoised; then, the peak time points of the two curves are located using local maximum detection on the denoised waveform, and the peak time difference is obtained. .

[0035] Preferably, step three also includes:

[0036] S34. Obtaining the peak time difference After dimensionless processing, the stress resistance hysteresis coefficient SDI is calculated by combining the stress period Tp.

[0037] S35. By setting a preset mechanical fatigue hysteresis threshold Sth, and comparing the stress resistance hysteresis coefficient SDI with the mechanical fatigue hysteresis threshold Sth, the third evaluation results are obtained, including:

[0038] When the stress resistance hysteresis coefficient SDI < mechanical fatigue hysteresis threshold Sth, it indicates that the resistance response is synchronized with the change of mechanical stress, there is no risk of mechanical fatigue, and continuous monitoring is required.

[0039] When the stress resistance hysteresis coefficient SDI is greater than or equal to the mechanical fatigue hysteresis threshold Sth, it indicates that the resistance response lags behind the change in mechanical stress, and the internal conductive path or heating wire structure has become loose or cracked, posing a risk of mechanical fatigue. This triggers the third warning instruction, which marks the current heating pad with a mechanical fatigue risk label and initiates the source tracing process.

[0040] Preferably, step four includes:

[0041] S41. Extract the original electrical structure non-conformance labels, temperature consistency non-conformance labels, and mechanical fatigue potential risk labels, and perform correlation analysis with the corresponding production batch information and key process parameters to trace the key processes and procedures that caused the non-conformance.

[0042] S42. Based on the key processes and technological steps of traceability, and combined with the corresponding anomaly coefficients or indices, construct a corrective data model for the causes of anomalies; combine the model with standard parameters and standard process ranges to correct the abnormal parameters and obtain updated process data.

[0043] Preferably, step four also includes:

[0044] S43. Based on updated process data, automatically generate targeted production correction strategies, including: adjusting welding temperature and welding time to optimize solder joint quality; adjusting wiring routing to reduce mechanical stress concentration; adjusting insulation layer thickness and bonding pressure to improve electrical stability; adjusting curing temperature and time to ensure uniform material properties; and increasing the frequency of random stress testing to enhance fatigue hazard monitoring.

[0045] This invention provides a method for identifying quality anomalies in heating pads based on end-to-end process control. It offers the following advantages:

[0046] (1) The heating pad quality anomaly identification method based on full-process control can accurately identify minor anomalies in the electrical structure of the heating pad by using multi-frequency impedance spectrum and high-frequency pulse echo signal joint detection, thereby improving the accuracy and reliability of the original electrical structure qualification judgment.

[0047] (2) The heating pad quality anomaly identification method based on full-process control, by combining the dynamic monitoring method of temperature consistency index and mechanical stress response hysteresis coefficient, realizes the real-time assessment of heating pad thermal performance and mechanical fatigue risks, and significantly enhances the full-process control capability of product quality.

[0048] (3) The heating pad quality anomaly identification method based on full-process control can accurately locate the key processes and links of quality anomalies by adopting the correlation traceability technology between production batches and key process parameters, providing a scientific basis for targeted correction and effectively reducing production defects and rework rate.

[0049] (4) The heating pad quality anomaly identification method based on full-process control realizes dynamic optimization and closed-loop control of process parameters by automatically generating targeted production correction strategies, which improves the stability and consistency of the heating pad manufacturing process and significantly improves the overall quality and service life of the product. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the method steps in this application. Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] Example 1

[0053] Please see Figure 1 This invention provides a method for identifying quality anomalies in heating pads based on end-to-end control, comprising the following steps:

[0054] Step 1: With the car heating pad de-energized, apply a preset multi-frequency micro-voltage signal to the heating wire circuit and collect the impedance amplitude Zf and phase angle at each frequency point. The impedance spectrum shift index (ISI) was calculated and obtained. A high-frequency narrow pulse voltage signal was applied to the power input terminal of the same heating pad, and the transient voltage echo waveform (Vecho), the input pulse voltage waveform (Vin), the reference voltage (Vbase), and the transient echo voltage were acquired. Calculate and obtain the echo reflection coefficient Rb; further calculate and obtain the line structure integrity factor Gimp, and compare and analyze it with the impedance spectrum offset index ISI, the line structure integrity threshold Gth, and the impedance spectrum offset tolerance threshold Ith to determine whether the original electrical structure of the heating pad is qualified. If it is qualified, proceed to step two; if it is not qualified, mark the label and enter the traceability stage.

[0055] Step 2: Apply constant power to the heating pad sample with qualified original electrical structure for heating; collect the time series of temperature values ​​TW(t) of the hot wire temperature rise curve and the spatial distribution time series of the heating pad surface temperature in real time. Calculate and obtain the temperature consistency index (TCI), and compare it with the temperature consistency threshold (Tth) to determine whether the thermal inertia and temperature consistency of the heating pad are qualified. If qualified, proceed to step three; if not qualified, mark the label and enter the traceability stage.

[0056] Step 3: For heating pad samples with qualified thermal inertia and temperature consistency, a periodic mechanical stress test is applied by the loading device under heating conditions. The mechanical stress change curve and the heating pad resistance change curve are collected in real time. The stress resistance hysteresis coefficient SDI is calculated and compared with the mechanical fatigue hysteresis threshold Sth to determine whether there is a risk of mechanical fatigue. If there is a risk, a label is marked and the product enters the traceability stage.

[0057] Step 4: By extracting original electrical structure non-conformance labels, temperature consistency non-conformance labels, and mechanical fatigue potential risk labels, and combining them with production batches and key process parameters, trace the key processes and links that are non-conforming; construct a correction data model based on the traceability results and abnormal indicators, and correct abnormal process parameters in combination with standard parameters to update process data; automatically generate targeted production correction strategies.

[0058] In this embodiment, through comprehensive testing and dynamic evaluation of multi-dimensional electrical, thermal performance and mechanical fatigue, combined with precise traceability of production batches and process parameters, the entire process of closed-loop control and intelligent correction of heating pad quality abnormalities is realized, which significantly improves the accuracy of product testing and the optimization effect of production process, and effectively ensures the stability and reliability of heating pads.

[0059] Example 2

[0060] This embodiment is an explanation based on Embodiment 1. Please refer to it. Figure 1 Specifically, step one includes:

[0061] S11. With the automotive heating pad de-energized, a preset multi-frequency micro-voltage signal (frequency range 100Hz~10MHz, amplitude ≤1VPP) is applied to the heating wire circuit using precision impedance analysis. The impedance amplitude Zf and phase angle at each frequency point are collected by an impedance measuring device installed on the test fixture. ;

[0062] S12, through impedance amplitude Zf and phase angle Using spectrum fitting calculation techniques, after dimensionless processing, the distributed capacitance value Cf and the distributed inductance value Lf are calculated and obtained, as shown in the following formula:

[0063]

[0064]

[0065] S13. Perform median filtering on the impedance amplitude Zf, distributed capacitance Cf, and distributed inductance Lf corresponding to the frequency point to remove random noise and occasional abnormal data during the measurement process, thereby improving the continuity and smoothness of the parameter curve.

[0066] S14. Compare and analyze the impedance amplitude Zf, distributed capacitance Cf, and distributed inductance Lf curves with the pre-established standard curve data of good products; obtain the impedance spectrum shift index ISI based on the deviation of the impedance amplitude.

[0067] In this embodiment, by employing precise impedance analysis combined with spectrum fitting calculation and median filtering technology, measurement noise and abnormal data are effectively removed, and the electrical parameters of the heating wire circuit are accurately obtained. This enables high-precision non-destructive testing of the electrical structure of the heating pad, improving the accuracy of impedance spectrum shift index discrimination and the stability of the test.

[0068] Example 3

[0069] This embodiment is an explanation based on Embodiment 2. Please refer to it. Figure 1 Specifically, step one also includes:

[0070] S15. Apply a high-frequency narrow-pulse voltage signal to the power input terminal of the same heating pad. Acquire the transient voltage echo waveform Vecho and the input pulse voltage waveform Vin using a high-bandwidth oscilloscope connected to the heating pad, and simultaneously acquire the reference voltage Vbase. At the time tref when the echo signal first appears, acquire the transient echo voltage. ;

[0071] S16. The transient voltage echo waveform Vecho, the input pulse voltage waveform Vin, and the transient echo voltage are acquired through data collection. After dimensionless processing, the echo reflection coefficient Rb is calculated using the time-domain reflectometry method, as shown in the following formula:

[0072]

[0073] In this embodiment, by applying a high-frequency narrow pulse voltage signal and combining it with a high-bandwidth oscilloscope to collect transient voltage echoes in real time, time-domain reflection detection of the circuit structure at the power input terminal of the heating pad is realized, which effectively improves the accuracy and sensitivity of circuit fault location and enhances the ability to judge the integrity of electrical structure.

[0074] Example 4

[0075] This embodiment is an explanation based on Embodiment 3. Please refer to it. Figure 1 Specifically, step one also includes:

[0076] S17. By obtaining the impedance spectrum shift index ISI and the echo reflection coefficient Rb, and after dimensionless processing, the line structure integrity factor Gimp is calculated comprehensively, as shown in the following formula:

[0077]

[0078] In the formula, and Indicates the weighting coefficient;

[0079] and The method of obtaining the Gimp factor is as follows: It is determined through statistical regression analysis of a large number of sample echo reflection and impedance spectrum data. Combined with calibration experimental data, algorithms such as least squares fitting are used to optimize the weight allocation, ensuring that the calculated line structure integrity factor Gimp accurately reflects the actual electrical structure state and that the weight coefficients meet the constraints. This ensures the scientific rigor and rationality of the comprehensive evaluation.

[0080] S18. By setting a line structure integrity threshold Gth and an impedance spectrum shift tolerance threshold Ith, and comparing the line structure integrity factor Gimp and the impedance spectrum shift index II with the line structure integrity threshold Gth and the impedance spectrum shift tolerance threshold Ith, the first evaluation results are obtained, including:

[0081] When the line structure integrity factor Gimp ≥ the line structure integrity threshold Gth, and the impedance spectrum offset index ISI < the impedance spectrum offset tolerance threshold Ith, it indicates that the original electrical structure of the heating pad is qualified, and proceed to step two.

[0082] When any one of the following conditions is not met: the line structure integrity factor Gimp ≥ the line structure integrity threshold Gth, and the impedance spectrum offset index ISI < the impedance spectrum offset tolerance threshold Ith, it indicates that the original electrical structure of the heating pad is unqualified, triggering the first warning instruction, marking the current heating pad with the original electrical structure unqualified label, and entering the traceability stage.

[0083] The method for obtaining the circuit structure integrity threshold Gth is as follows: Through statistical analysis of the circuit structure integrity factor Gimp in a large amount of heating pad electrical response test data, the distribution range of Gimp under normal electrical structure conditions is extracted. Combined with the experience judgment of professional electrical engineers, a reasonable circuit structure integrity threshold Gth is determined. Relevant electrical product industry standards and equipment manufacturer technical specifications are referenced. These specifications typically provide a pass / fail threshold range for circuit structure integrity. This threshold can effectively distinguish between the pass / fail and abnormal states of the heating pad's electrical structure, ensuring the stability and safety of the product's electrical performance.

[0084] Method for obtaining the impedance spectrum offset tolerance threshold Ith: Based on the statistical and spectral analysis of a large amount of heating pad impedance spectrum data, the numerical distribution of the impedance spectrum offset index ISI under normal and abnormal conditions is extracted. Combined with the judgment of experienced technicians, the impedance spectrum offset tolerance threshold Ith is reasonably determined. With reference to relevant industry technical standards and manufacturer recommendations, the set threshold can effectively limit the impedance offset amplitude and ensure the consistency and reliability of the electrical performance of the heating pad.

[0085] In this embodiment, by comprehensively calculating the circuit structure integrity factor Gimp and combining it with the preset integrity threshold and impedance spectrum offset tolerance threshold, an accurate quantitative assessment of the original electrical structure of the heating pad is achieved. This can effectively distinguish between qualified and unqualified products, trigger early warnings and mark anomalies in a timely manner, and significantly improve the reliability of detection and the quality control level of the production process.

[0086] Example 5

[0087] This embodiment is an explanation based on Embodiment 4. Please refer to it. Figure 1 Specifically, step two includes:

[0088] S21. For heating pad samples with qualified original electrical structure, apply constant power for heating without damaging their structural integrity.

[0089] S22. Obtain the time series of temperature values ​​TW(t) of the heating wire temperature rise curve using the temperature sensor on the heating wire; obtain the time series of spatial distribution of surface temperature of the heating pad using the installed surface temperature sensor array. .

[0090] In this embodiment, by applying constant power heating while maintaining the structural integrity of the heating pad, and by using multi-point temperature sensors to collect real-time temporal and spatial distribution data of the temperature of the hot wire and the surface of the heating pad, accurate dynamic monitoring of the thermal performance of the heating pad is achieved, providing reliable basic data support for subsequent temperature consistency analysis.

[0091] Example 6

[0092] This embodiment is an explanation based on Embodiment 5. Please refer to it. Figure 1 Specifically, step two also includes:

[0093] S23. The time series of temperature values ​​TW(t) from the hot wire temperature rise curve and the time series of spatial distribution of the heating pad surface temperature. After dimensionless processing, the Temperature Consistency Index (TCI) is calculated using the following formula:

[0094]

[0095] In the formula, tmax represents the total sampling time. This represents the time series of temperature values ​​in the heating wire temperature rise curve. A time series representing the spatial average surface temperature of the heating pad;

[0096] S24. By setting a preset temperature consistency threshold Tth, and comparing the temperature consistency index TCI with the temperature consistency threshold Tth, the second evaluation results are obtained, including:

[0097] When the temperature consistency index TCI is greater than or equal to the temperature consistency threshold Tth, it indicates that the heating pad's thermal inertia and temperature consistency are qualified, and proceed to step three;

[0098] When the temperature consistency index TCI is less than the temperature consistency threshold Tth, it indicates that the heating pad's thermal inertia and temperature consistency are unqualified, triggering a second warning instruction to mark the current heating pad with a temperature consistency unqualified label and enter the traceability stage.

[0099] The method for obtaining the temperature consistency threshold Tth is as follows: Based on statistical analysis of a large amount of heating pad temperature test data, the distribution range of the temperature consistency index under normal temperature distribution consistency and abnormal non-uniformity is extracted. Combined with the experience judgment of thermal engineering experts and heating pad design specifications, a reasonable temperature consistency judgment threshold is determined. Referencing relevant quality standards and product performance test specifications in the heating pad industry, these standards usually give the acceptable range of temperature uniformity and thermal inertia indicators. This threshold is used to effectively distinguish between the acceptable and abnormal states of heating pad thermal performance, ensuring the stability of heating pad temperature control and the safety of use.

[0100] In this embodiment, by comparing the dimensionless temperature consistency index (TCI) with the preset threshold Tth, the thermal inertia and temperature distribution uniformity of the heating pad are accurately assessed. This effectively identifies heating pad samples with abnormal temperature consistency, marks them as unqualified, and triggers an early warning, thereby improving the accuracy and reliability of product quality control.

[0101] Example 7

[0102] This embodiment is an explanation based on Embodiment 6. Please refer to it. Figure 1 Specifically, step three includes:

[0103] S31. For heating pad samples with qualified thermal inertia and temperature consistency, a periodic mechanical stress test (simulating human backrest stress) is applied by the loading device under heating conditions, with the period set as Tp.

[0104] S32. The mechanical stress is measured in real time by a miniature force sensor and converted into stress value by a signal conditioning module to obtain the curve of mechanical stress changing over time; the resistance of the heating pad is measured in real time by a four-terminal resistance measuring device and synchronously recorded by a data acquisition card DAQ to obtain the curve of heating pad resistance changing over time.

[0105] S33. The mechanical stress versus time curve and the heating pad resistance versus time curve are aligned using synchronous sampling; the resulting sequence is denoised; then, the peak time points of the two curves are located using local maximum detection on the denoised waveform, and the peak time difference is obtained. .

[0106] In this embodiment, by synchronously sampling the time series of mechanical stress and heating pad resistance, and combining noise reduction processing and peak time point location, the hysteresis characteristics of resistance change under mechanical stress can be accurately captured, enabling precise detection and evaluation of the mechanical fatigue behavior of the heating pad, and effectively improving the scientificity and reliability of product durability risk identification.

[0107] Example 8

[0108] This embodiment is an explanation based on Embodiment 7. Please refer to it. Figure 1 Specifically, step three also includes:

[0109] S34. Obtaining the peak time difference Combining the stress period Tp, after dimensionless processing, the stress resistance hysteresis coefficient SDI is calculated as follows:

[0110]

[0111] S35. By setting a preset mechanical fatigue hysteresis threshold Sth, and comparing the stress resistance hysteresis coefficient SDI with the mechanical fatigue hysteresis threshold Sth, the third evaluation results are obtained, including:

[0112] When the stress resistance hysteresis coefficient SDI < mechanical fatigue hysteresis threshold Sth, it indicates that the resistance response is synchronized with the change of mechanical stress, there is no risk of mechanical fatigue, and continuous monitoring is required.

[0113] When the stress resistance hysteresis coefficient SDI is greater than or equal to the mechanical fatigue hysteresis threshold Sth, it indicates that the resistance response lags behind the change in mechanical stress, and the internal conductive path or heating wire structure has become loose or cracked, posing a risk of mechanical fatigue. This triggers the third warning instruction, which marks the current heating pad with a mechanical fatigue risk label and initiates the source tracing process.

[0114] The mechanical fatigue hysteresis threshold Sth is obtained by statistically analyzing a large amount of resistance response data of heating pads under periodic mechanical stress, extracting the distribution range of stress resistance hysteresis coefficients under normal synchronous response and potential mechanical fatigue states, and combining the experience judgment of materials mechanics experts and relevant mechanical fatigue test results to determine a reasonable mechanical fatigue hysteresis judgment threshold. Reference is made to heating pad material performance standards, mechanical fatigue testing specifications, and industry safety operation requirements, which typically specify the judgment indicators and limits for mechanical fatigue risk. This threshold is used to accurately identify the potential loosening or cracking risks in the internal conductive path or heating wire structure of the heating pad, ensuring the mechanical stability and service life of the heating pad.

[0115] In this embodiment, by calculating the stress resistance hysteresis coefficient SDI and comparing it with the preset mechanical fatigue hysteresis threshold Sth, the fatigue potential of the internal conductive path and heating wire structure of the heating pad can be accurately identified. This enables early detection of potential mechanical fatigue risks, ensuring the safety and reliability of the product and effectively avoiding failures and performance degradation caused by mechanical fatigue.

[0116] Example 9

[0117] This embodiment is an explanation based on Embodiment 8. Please refer to it. Figure 1 Specifically, step four includes:

[0118] S41. Extract the original electrical structure non-conformance labels, temperature consistency non-conformance labels, and mechanical fatigue potential risk labels, and perform correlation analysis with the corresponding production batch information and key process parameters (such as welding temperature, welding time, wiring direction, insulation layer thickness, bonding pressure, curing temperature, stress test frequency, etc.) to trace the key processes and procedures that caused the non-conformance.

[0119] S42. Based on the key processes and technological steps of traceability, and combined with the corresponding anomaly coefficients or indices, construct a corrective data model for the causes of anomalies; combine the model with standard parameters and standard process ranges to correct the abnormal parameters and obtain updated process data.

[0120] In this embodiment, the system extracts multi-dimensional non-conforming labels and combines them with production batches and key process parameters for traceability, accurately locating the key processes and steps that cause abnormal heating pad quality. Based on the traceability results, a correction data model is constructed to achieve scientific correction of abnormal process parameters and dynamic optimization of process data, effectively improving the stability of the production process and product consistency, and significantly reducing the non-conforming rate and production costs.

[0121] Example 10

[0122] This embodiment is an explanation based on Embodiment 9. Please refer to it. Figure 1Specifically, step four also includes:

[0123] S43. Based on updated process data, automatically generate targeted production correction strategies, including: adjusting welding temperature and welding time to optimize solder joint quality; adjusting wiring routing to reduce mechanical stress concentration; adjusting insulation layer thickness and bonding pressure to improve electrical stability; adjusting curing temperature and time to ensure uniform material properties; and increasing the frequency of random stress testing to enhance fatigue hazard monitoring.

[0124] In this embodiment, by using a targeted production correction strategy automatically generated based on updated process data, key processes such as welding parameters, wiring layout, insulation layer thickness, and bonding pressure can be precisely adjusted to optimize the electrical performance and mechanical structure stability of the heating pad. At the same time, the uniformity of the curing process and the frequency of fatigue hazard monitoring are improved, thereby comprehensively improving product quality and reliability, significantly reducing the production defect rate, and ensuring the long-term stable operation of the heating pad.

[0125] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for identifying quality anomalies in heating pads based on full-process control, characterized in that, Includes the following steps: Step 1: With the car heating pad de-energized, apply a preset multi-frequency micro-voltage signal to the heating wire circuit and collect the impedance amplitude Zf and phase angle at each frequency point. The impedance spectrum shift index (ISI) was calculated and obtained. A high-frequency narrow pulse voltage signal was applied to the power input terminal of the same heating pad, and the transient voltage echo waveform (Vecho), the input pulse voltage waveform (Vin), the reference voltage (Vbase), and the transient echo voltage were acquired. Calculate and obtain the echo reflection coefficient Rb; further calculate and obtain the line structure integrity factor Gimp, and compare and analyze it with the impedance spectrum offset index ISI, the line structure integrity threshold Gth, and the impedance spectrum offset tolerance threshold Ith to determine whether the original electrical structure of the heating pad is qualified. If it is qualified, proceed to step two; if it is not qualified, mark the label and enter the traceability stage. Step 2: Apply constant power to the heating pad sample with qualified original electrical structure for heating; collect the time series of temperature values ​​TW(t) of the hot wire temperature rise curve and the spatial distribution time series of the heating pad surface temperature in real time. Calculate and obtain the temperature consistency index (TCI), and compare it with the temperature consistency threshold (Tth) to determine whether the thermal inertia and temperature consistency of the heating pad are qualified. If qualified, proceed to step three; if not qualified, mark the label and enter the traceability stage. Step 3: For heating pad samples with qualified thermal inertia and temperature consistency, a periodic mechanical stress test is applied by the loading device under heating conditions. The mechanical stress change curve and the heating pad resistance change curve are collected in real time. The stress resistance hysteresis coefficient SDI is calculated and compared with the mechanical fatigue hysteresis threshold Sth to determine whether there is a risk of mechanical fatigue. If there is a risk, a label is marked and the product enters the traceability stage. Step 4: By extracting original electrical structure non-conformance labels, temperature consistency non-conformance labels, and mechanical fatigue potential risk labels, and combining them with production batches and key process parameters, trace the key processes and links that are non-conforming; construct a correction data model based on the traceability results and abnormal indicators, and correct abnormal process parameters in combination with standard parameters to update process data; automatically generate targeted production correction strategies.

2. The heating pad quality anomaly identification method based on full-process control according to claim 1, characterized in that, Step one includes: S11. With the automotive heating pad de-energized, a preset multi-frequency micro-voltage signal is applied to the heating wire circuit using precision impedance analysis. The impedance amplitude Zf and phase angle at each frequency point are collected by an impedance measuring device mounted on the test fixture. ; S12, through impedance amplitude Zf and phase angle Using spectrum fitting calculation technology, after dimensionless processing, the distributed capacitance value Cf and the distributed inductance value Lf are calculated and obtained; S13. Perform median filtering on the impedance amplitude Zf, distributed capacitance Cf, and distributed inductance Lf corresponding to the frequency point to remove random noise and occasional abnormal data during the measurement process, thereby improving the continuity and smoothness of the parameter curve. S14. Compare and analyze the impedance amplitude Zf, distributed capacitance Cf, and distributed inductance Lf curves with the pre-established standard curve data of good products; obtain the impedance spectrum shift index ISI based on the deviation of the impedance amplitude.

3. The heating pad quality anomaly identification method based on full-process control according to claim 2, characterized in that, Step one also includes: S15. Apply a high-frequency narrow-pulse voltage signal to the power input terminal of the same heating pad. Acquire the transient voltage echo waveform Vecho and the input pulse voltage waveform Vin using a high-bandwidth oscilloscope connected to the heating pad, and simultaneously acquire the reference voltage Vbase. At the time tref when the echo signal first appears, acquire the transient echo voltage. ; S16. The transient voltage echo waveform Vecho, the input pulse voltage waveform Vin, and the transient echo voltage are acquired through data collection. After dimensionless processing, the echo reflection coefficient Rb is calculated using the time-domain reflectometry method.

4. The heating pad quality anomaly identification method based on full-process control according to claim 3, characterized in that, Step one also includes: S17. By obtaining the impedance spectrum shift index ISI and the echo reflection coefficient Rb, and after dimensionless processing, the line structure integrity factor Gimp is obtained through comprehensive calculation. S18. By setting a line structure integrity threshold Gth and an impedance spectrum shift tolerance threshold Ith, and comparing the line structure integrity factor Gimp and the impedance spectrum shift index II with the line structure integrity threshold Gth and the impedance spectrum shift tolerance threshold Ith, the first evaluation results are obtained, including: When the line structure integrity factor Gimp ≥ the line structure integrity threshold Gth, and the impedance spectrum offset index ISI < the impedance spectrum offset tolerance threshold Ith, it indicates that the original electrical structure of the heating pad is qualified, and proceed to step two. When any one of the following conditions is not met: the line structure integrity factor Gimp ≥ the line structure integrity threshold Gth, and the impedance spectrum offset index ISI < the impedance spectrum offset tolerance threshold Ith, it indicates that the original electrical structure of the heating pad is unqualified, triggering the first warning instruction, marking the current heating pad with the original electrical structure unqualified label, and entering the traceability stage.

5. The heating pad quality anomaly identification method based on full-process control according to claim 4, characterized in that, Step two includes: S21. For heating pad samples with qualified original electrical structure, apply constant power for heating without damaging their structural integrity. S22. Obtain the time series of temperature values ​​TW(t) of the heating wire temperature rise curve using the temperature sensor on the heating wire; obtain the time series of spatial distribution of surface temperature of the heating pad using the installed surface temperature sensor array. .

6. The heating pad quality anomaly identification method based on full-process control according to claim 5, characterized in that, Step two also includes: S23. The time series of temperature values ​​TW(t) from the hot wire temperature rise curve and the time series of spatial distribution of the heating pad surface temperature. After dimensionless processing, the temperature uniformity index (TCI) is calculated and obtained. S24. By setting a preset temperature consistency threshold Tth, and comparing the temperature consistency index TCI with the temperature consistency threshold Tth, the second evaluation results are obtained, including: When the temperature consistency index TCI is greater than or equal to the temperature consistency threshold Tth, it indicates that the heating pad's thermal inertia and temperature consistency are qualified, and proceed to step three; When the temperature consistency index TCI is less than the temperature consistency threshold Tth, it indicates that the heating pad's thermal inertia and temperature consistency are unqualified, triggering a second warning instruction to mark the current heating pad with a temperature consistency unqualified label and enter the traceability stage.

7. The heating pad quality anomaly identification method based on full-process control according to claim 6, characterized in that, Step three includes: S31. For heating pad samples with qualified thermal inertia and temperature consistency, a periodic mechanical stress test is applied by the loading device under heating conditions, with the period set as Tp. S32. The mechanical stress is measured in real time by a miniature force sensor and converted into stress value by a signal conditioning module to obtain the curve of mechanical stress changing over time; the resistance of the heating pad is measured in real time by a four-terminal resistance measuring device and synchronously recorded by a data acquisition card DAQ to obtain the curve of heating pad resistance changing over time. S33. The mechanical stress versus time curve and the heating pad resistance versus time curve are aligned using synchronous sampling; the resulting sequence is denoised; then, the peak time points of the two curves are located using local maximum detection on the denoised waveform, and the peak time difference is obtained. .

8. The heating pad quality anomaly identification method based on full-process control according to claim 7, characterized in that, Step three also includes: S34. Obtaining the peak time difference Combined with the stress period Tp, after dimensionless processing, the stress resistance hysteresis coefficient SDI is calculated and obtained. S35. By setting a preset mechanical fatigue hysteresis threshold Sth, and comparing the stress resistance hysteresis coefficient SDI with the mechanical fatigue hysteresis threshold Sth, the third evaluation results are obtained, including: When the stress resistance hysteresis coefficient SDI < mechanical fatigue hysteresis threshold Sth, it indicates that the resistance response is synchronized with the change of mechanical stress, there is no risk of mechanical fatigue, and continuous monitoring is required. When the stress resistance hysteresis coefficient SDI is greater than or equal to the mechanical fatigue hysteresis threshold Sth, it indicates that the resistance response lags behind the change in mechanical stress, and the internal conductive path or heating wire structure has become loose or cracked, posing a risk of mechanical fatigue. This triggers the third warning instruction, which marks the current heating pad with a mechanical fatigue risk label and initiates the source tracing process.

9. The heating pad quality anomaly identification method based on full-process control according to claim 8, characterized in that, Step four includes: S41. Extract the original electrical structure non-conformance labels, temperature consistency non-conformance labels, and mechanical fatigue potential risk labels, and perform correlation analysis with the corresponding production batch information and key process parameters to trace the key processes and procedures that caused the non-conformance. S42. Based on the key processes and technological steps of traceability, and combined with the corresponding anomaly coefficients or indices, construct a corrective data model for the causes of anomalies; combine the model with standard parameters and standard process ranges to correct the abnormal parameters and obtain updated process data.

10. The heating pad quality anomaly identification method based on full-process control according to claim 9, characterized in that, Step four also includes: S43. Based on updated process data, automatically generate targeted production correction strategies, including: adjusting welding temperature and welding time to optimize solder joint quality; adjusting wiring routing to reduce mechanical stress concentration; adjusting insulation layer thickness and bonding pressure to improve electrical stability; adjusting curing temperature and time to ensure uniform material properties; and increasing the frequency of random stress testing to enhance fatigue hazard monitoring.

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