Method, device and equipment for testing electrical performance of vehicle-mounted wire harness
By employing constant slope current excitation and energy domain analysis in high-power automotive wiring harnesses, thermal resistance references and slip characteristic values are obtained, solving the problem of low detection accuracy and achieving accurate slip detection under strong thermal drift and inductive interference.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SUZHOU YUEHONGSHENG TECH CO LTD
- Filing Date
- 2026-01-27
- Publication Date
- 2026-04-24
AI Technical Summary
Existing detection technologies struggle to distinguish between normal temperature rises and abnormal minute slippage in high-power automotive wiring harnesses, resulting in low detection accuracy and a high risk of missed detections or misjudgments.
Test data is acquired using constant slope current excitation. The optimal linear region and thermal resistance reference are obtained through resampling and sliding window analysis. The impedance change rate and slip characteristic value are extracted, and the test results are generated by combining the heat dissipation correction factor.
It can accurately detect slippage under strong thermal drift and inductive interference, improve detection accuracy, avoid missed detection and misjudgment, and adapt to the detection needs of wire harnesses of different specifications.
Smart Images
Figure CN121917875A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of testing technology for new energy vehicle components, specifically to a method, device, and equipment for testing the electrical performance of vehicle wiring harnesses. Background Technology
[0002] In the manufacturing process of high-power automotive wiring harnesses, the crimping quality between aluminum conductors and copper terminals directly affects the operational safety of new energy vehicles. Due to the difference in the coefficients of thermal expansion between aluminum and copper, thermal stress will be generated at the crimping interface when the wiring harness carries a large current. If the mechanical holding force is insufficient, microscopic slippage will occur at the contact surface, which will lead to increased contact resistance or even ablation failure over a long period of time. Therefore, it is necessary to effectively detect this potential "under-crimping" defect during the production line stage.
[0003] However, existing detection technologies mainly rely on dynamic resistance monitoring. During the application of a large current sufficient to induce thermal stress, the resistance of the aluminum conductor itself experiences significant thermal drift as temperature rises. Furthermore, during rapid loading of the large current, the inherent inductance of the test circuit generates an induced voltage, which is superimposed on the resistance signal. This strong thermal drift background and inductive interference make it difficult for traditional detection methods to distinguish between normal temperature rises and abnormal minute slippage from complex mixed signals, easily leading to missed detections or misjudgments. Summary of the Invention
[0004] To address the technical problem of low detection accuracy caused by thermal drift and inductive interference masking weak slip signals, the present invention aims to provide a method, apparatus, and equipment for testing the electrical performance of automotive wiring harnesses. The specific technical solution adopted is as follows: A method for testing the electrical performance of an automotive wiring harness, the method comprising: Acquire test data of the vehicle wiring harness under constant slope current excitation; resample the test data based on a preset energy step size to obtain the current, voltage and total heat energy injected into the wiring harness to be analyzed, and obtain the impedance of each data point; A preset sliding window is slid across the entire data process. The linear relationship between the impedance and the total energy within the window after each slide is analyzed to obtain the optimal linear region. The slope of the regression line between the impedance and the total energy is extracted within the optimal linear region, and a thermal resistance benchmark is obtained by combining it with a preset heat dissipation correction factor. The impedance change rate of each data point is extracted based on the changes in impedance and the changes in total heat energy. The sliding characteristic value of each data point is obtained by comparing the impedance change rate with the thermal resistance benchmark. Based on the distribution of the slip feature values within the optimal linear region, a slip determination threshold is obtained; based on the slip determination threshold and the slip feature values of the entire process data, a test result is generated.
[0005] Furthermore, the method for obtaining the optimal linear region includes: For each sliding window, a univariate linear regression analysis is performed on the impedance and the total energy to obtain the coefficient of determination; based on the coefficient of determination, the optimal linear region is selected.
[0006] Furthermore, the method for obtaining the slip characteristic value includes: The impedance change rate is baseline-corrected and truncated to negative values using the thermal resistance reference to obtain the slip characteristic value of each data point.
[0007] Furthermore, the method for obtaining the slip determination threshold includes: The mean and standard deviation of the slip characteristic values within the optimal linear region are combined to obtain the slip determination threshold.
[0008] Furthermore, the method for obtaining the test results includes: Search in chronological order, mark the index of the first data point whose first consecutive preset length of the slip characteristic value is greater than the slip determination threshold as an invalid index, and leave the flag empty if not found. Extract the critical failure current corresponding to the failure index, compare the critical failure current with the preset qualified current, or generate test results based on the status of the flag bit.
[0009] Furthermore, the method for generating test results by comparing the failure critical current with the preset qualified current, or based on the state of the flag bit, includes: When the flag bit is empty, or the failure critical current is not less than the preset qualified current, the product is judged to be qualified. When the failure critical current is less than the preset qualified current, the product is determined to be unqualified.
[0010] Furthermore, the linear relationship between the impedance and the total energy is analyzed based on the least squares method.
[0011] Furthermore, the length of the preset sliding window is 10% of the total data points to be analyzed, and the sliding step size is half the window length.
[0012] The present invention also proposes an electrical performance testing device for vehicle wiring harnesses, the device comprising: The acquisition module is used to acquire test data of the vehicle wiring harness under constant slope current excitation; the test data is resampled based on a preset energy step size to obtain the current, voltage and total heat energy injected into the wiring harness to be analyzed, and the impedance of each data point is acquired. The analysis module is used to slide a preset sliding window across the entire process data, analyze the linear relationship between the impedance and the total energy within the window after each slide, and obtain the optimal linear region; extract the slope of the regression line between the impedance and the total energy within the optimal linear region, and obtain the thermal resistance benchmark by combining it with a preset heat dissipation correction factor; extract the impedance change rate for each data point based on the changes in impedance and the changes in total heat energy; and compare the impedance change rate with the thermal resistance benchmark to obtain the sliding characteristic value of each data point. The determination module is used to obtain a slip determination threshold based on the distribution of the slip feature values within the optimal linear region; and to generate test results based on the slip determination threshold and the slip feature values of the whole process data.
[0013] The present invention also proposes an electrical performance testing device for vehicle wiring harnesses, the device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement any of the steps of the electrical performance testing method for vehicle wiring harnesses described above.
[0014] The present invention has the following beneficial effects: This invention first acquires test data under constant slope current excitation, ensuring that the induced voltage generated by the inductor in the test circuit remains constant during loading. Then, based on a preset energy step size, resampling is performed to obtain the data to be analyzed, providing a basis for subsequent analysis. Next, the optimal linear region is identified to avoid the nonlinear region where inductive reactance is severely affected, resulting in the region that best reflects the thermal resistance characteristics of the material. Within the optimal linear region, the slope of the regression line between impedance and total energy is extracted to obtain a thermal resistance benchmark, providing a stable and accurate physical reference for separating weak mechanical slip signals from a strong thermal drift background. Furthermore, the impedance change rate of each data point is extracted, and compared with the thermal resistance benchmark to obtain the slip characteristic value of each data point, highlighting the slip positive pulse in the residual signal. Further, based on the distribution of slip characteristic values within the optimal linear region, a slip judgment threshold is obtained, avoiding the use of empirically fixed thresholds that lead to poor adaptability to different wire harness specifications, thus improving detection adaptability. Finally, based on the slip judgment threshold and the slip characteristic values of the entire process data, test results are generated. This invention uses constant slope excitation and energy domain analysis to adaptively extract thermal resistance references and calculate slip characteristics, thereby accurately detecting slip under strong thermal drift and inductive interference, solving the problem of missed detection and misjudgment in traditional methods. Attached Figure Description
[0015] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0016] Figure 1 A flowchart illustrating an electrical performance testing method for an on-board wiring harness according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a module for testing the electrical performance of an on-board wiring harness, as provided in one embodiment of the present invention. Detailed Implementation
[0017] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a method, apparatus, and device for testing the electrical performance of an automotive wiring harness according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable manner.
[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
[0019] The following description, in conjunction with the accompanying drawings, details the specific scheme of the electrical performance testing method, testing device, and equipment for vehicle wiring harnesses provided by the present invention.
[0020] Please see Figure 1 The diagram illustrates a flowchart of an electrical performance testing method for an on-board wiring harness according to an embodiment of the present invention, specifically including: Step S1: Obtain test data of the vehicle wiring harness under constant slope current excitation; resample the test data based on the preset energy step size to obtain the current, voltage and total heat energy injected into the wiring harness to be analyzed, and obtain the impedance of each data point.
[0021] This method uses constant-slope current excitation as its physical basis. The excitation current has a constant rate of change, ensuring that the induced voltage generated by the inductance of the test circuit remains constant during loading. This constant induced voltage means that the inductive reactance component exhibits a regular attenuation characteristic in the impedance signal, laying a deterministic foundation for subsequent algorithmic separation.
[0022] Meanwhile, linear current excitation and energy domain analysis methods have inherent synergy. The thermal drift of aluminum conductor resistance is essentially a function of Joule heat accumulation. Under linear current growth conditions, when the observation coordinate system is converted from time to accumulated heat energy, the resistance change caused by the normal temperature rise of the material exhibits a linear trend with an approximately fixed slope. This transforms the complex nonlinear background drift into an easily tractable constant reference, significantly reducing the difficulty of extracting weak slip signals from a strong thermal background.
[0023] In one embodiment of the invention, the programmable DC power supply is controlled to operate in a constant current slew rate mode. The maximum test current is set. (In this embodiment, 300A is used) and target rise time (200ms is used in this embodiment).
[0024] The power controller calculates the rate of change of current based on the above parameters. (In this embodiment, it is 1500A / s). Then, control the power supply output current. Starting from 0A, with a fixed slope linearly increase to .
[0025] During this process, the current Over time The relationship strictly satisfies (Constant). This constant rate of change is what generates a constant induced voltage. The physical premise of this is also the basis for subsequent algorithms to filter out inductive reactance through the negative differential value characteristic. L represents the equivalent parasitic inductance of the test circuit, which is determined by the current loop formed by the power output line, test fixture, connection terminals and the wire harness under test itself.
[0026] Obtaining test data of vehicle wiring harnesses under constant slope current excitation: using a high-speed data acquisition unit at a fixed sampling frequency. (In this embodiment, the sampling frequency is 100kHz) The current signal of the test circuit and the voltage signal at both ends of the wire harness are acquired synchronously, with a sampling interval of 1 / The data acquisition process continues until the current reaches [a certain value]. It is held for a short period of time (e.g., 20-40ms) and then stopped, providing a detection window for possible delayed microslip caused by thermal stress accumulation or material creep, thereby improving the ability to detect potential failure modes.
[0027] Since the temperature rise of the aluminum conductor is directly related to the injected heat energy, but not directly linearly related to time (it is affected by the rate of change of current), it is also necessary to perform numerical integration on the collected voltage and current data based on the sampling interval and Joule's law, according to the directly collected current and voltage data, to calculate the total heat energy of the injected wire bundle up to each sampling time, and obtain the original total injected heat energy sequence, which provides a basis for the transformation of analysis dimensions.
[0028] The first original total injected thermal energy is 0, and the remaining original total injected thermal energy is the product of voltage, current and sampling interval, plus the sum of the previous total injected thermal energy.
[0029] The test data includes the measured data sequences of the raw current and raw voltage, as well as the indirectly obtained raw total injected heat energy sequence.
[0030] Furthermore, the test data is resampled based on a preset energy step size, transforming the data analysis dimension from the "time domain" to the "energy domain". This allows for the acquisition of the current, voltage, and total heat energy of the injected wire bundle to be analyzed, as well as the impedance of each data point, providing a basis for subsequent analysis.
[0031] Preferably, in one embodiment of the present invention, since the original data is based on a fixed time interval, the energy increment injected per unit time differs greatly between the initial stage of the test when the current is small and the later stage of the test when the current is large. Furthermore, in the initial stage of the test, the calculation results may diverge or generate huge numerical noise because the energy increment approaches the zero value of the machine's accuracy limit. At the same time, since the initial current is small and thermal stress has not yet been established, slippage is impossible. Therefore, the initial stage with small current needs to be skipped in subsequent analysis. Preset energy step size The step size for resampling should be greater than the minimum effective energy increment under system noise, which is 0.5J in this example. The original total injected thermal energy sequence is traversed, starting from the first point and searching sequentially. The difference between the total injected energy at each search point and the total injected energy at the starting point is taken as the energy difference. All points with an energy difference less than the starting point are discarded. The point, until the first energy difference equals The point is used as the second point, and resampling begins from the second point to construct a new energy axis. , , When the energy increment of the remaining data is less than a preset energy step... When necessary, discard the remaining data, or retain only the last original sampling point as the endpoint; A linear interpolation algorithm is used to map the original current and voltage data sequences onto a new energy axis, generating resampled current and voltage sequences. Additionally, to skip the initial phase with lower current, this example sets a lower current threshold of 10%. Based on the resampled current sequence, the current sequence below the lower current threshold is truncated and discarded. At the same time, the voltage sequence and the total heat energy sequence are also truncated. Then, based on the current and voltage of each data point, the impedance is obtained, that is, the ratio of the voltage value to the current value of each data point is used as the impedance. The impedance here is a characteristic calculation quantity that includes resistive and inductive reactance components.
[0032] Thus, the current, voltage, and total heat energy injected into the bundle to be analyzed are obtained, and the impedance of each data point is acquired. These data are strictly aligned on the energy axis. Since the total energy injected into the bundle increases with time, the energy axis and the time axis maintain a strict monotonic correspondence. The energy axis not only represents the amount of accumulated injected heat energy, but also implies time sequence information, that is, the data points also have a time sequence.
[0033] It should be noted that, for ease of distinction, the original measurement points obtained directly from data acquisition based on fixed time intervals are called "acquisition points"; while the points in the regularized sequence obtained after energy domain resampling and pre-screening, which are used for subsequent core analysis steps (such as linear regression and differential operations), are called "data points". In other embodiments of the present invention, the implementer may adjust the test setup, preset energy step size and current lower limit threshold according to the model and performance parameters of the vehicle wiring harness; the linear interpolation algorithm is a well-known technology and will not be described in detail here.
[0034] Step S2: Slide a preset sliding window across the entire process data, analyze the linear relationship between impedance and total energy within the window after each slide, and obtain the optimal linear region; extract the slope of the regression line between impedance and total energy within the optimal linear region, and obtain the thermal resistance benchmark by combining it with a preset heat dissipation correction factor; extract the impedance change rate for each data point based on the changes in impedance and total heat energy; compare the impedance change rate with the thermal resistance benchmark to obtain the sliding characteristic value of each data point.
[0035] Since the pure material thermal resistance effect exhibits strong linearity, while the inductive reactance component has strong nonlinearity, it will significantly reduce the linearity between impedance and total energy. Therefore, a preset sliding window is used to slide through the data throughout the process. The linear relationship between impedance and total energy within the window after each slide is analyzed to obtain the optimal linear region, so as to avoid the nonlinear region where the inductive reactance has a strong influence, and to obtain the region that best reflects the material thermal resistance characteristics. Then, considering that the heat dissipation of the harness to the environment under high current testing will cause a slight nonlinear decrease in the measured resistance-energy curve in the high energy range, the slope of the regression line of impedance and total energy is extracted in the optimal linear region. Combined with the preset heat dissipation correction factor, the thermal resistance reference is obtained, which provides a stable and accurate physical reference for separating weak mechanical slip signals from the background of strong thermal drift.
[0036] Preferably, in one embodiment of the present invention, the length of the preset sliding window is 10% of the total data points to be analyzed, and the sliding step is half the length of the window.
[0037] The entire process data consists of all data points to be analyzed. A univariate linear regression analysis is performed on the impedance and total energy within the window after each sliding step to obtain the coefficient of determination. The optimal linear region is selected based on the coefficient of determination.
[0038] As an example, the linear relationship between impedance and total energy is analyzed based on the least squares method. (Location) The sliding window position that is the largest and exceeds the preset goodness threshold (e.g., 0.99) will be locked as the best linear region for the corresponding data segment. Extract the slope K of the regression line between impedance and total energy corresponding to the optimal linear region; Considering that during the high-current, high-temperature phase, the heat dissipation of the wiring harness to the environment (heat convection and heat radiation) gradually increases, leading to a slight decrease in temperature rise efficiency, the slope K is adjusted in conjunction with a preset heat dissipation correction factor. The product of these is used as the thermal resistance reference. The value ranges from 0.90 to 0.98. It is obtained by offline calibration of a defect-free standard sample (e.g., the ratio of the measured slope in the high current section to the theoretical adiabatic slope). In this example, a value of 0.95 is used, which can also appropriately lower the baseline and ensure that even in the presence of measurement noise or a slight decrease in the actual thermal resistance slope due to heat dissipation, the slip signal can still be significantly higher than the baseline, thus preventing missed detections.
[0039] It should be noted that in linear analysis, total energy is used as the independent variable and impedance as the dependent variable; if the maximum If the preset quality threshold is not reached, it indicates that the quality of the wiring harness is extremely poor or the testing environment is extremely harsh, with no part of it being stable.
[0040] Considering that the high current region is least affected by inductive reactance and is physically closest to the true thermal resistance, even Slightly lower, but still the "most accurate" benchmark throughout the process, the window with the largest current is directly taken as the optimal linear region. The system outputs a warning "low benchmark confidence" but does not interrupt the test.
[0041] It should be noted that using the least squares method for linear regression analysis is a common technique used by those skilled in the art; in other embodiments of the present invention, implementers may adjust the sliding window settings themselves, which will not be elaborated here.
[0042] In the dimension of impedance change rate, physical effects from different sources exhibit distinctly different mathematical characteristics: material thermal resistance (temperature rise of aluminum wire) is a stable positive slope constant; loop inductive reactance (generated by constant slope current excitation) is a monotonically decaying negative value; while micro-slip at the crimp interface (mechanical failure) is a sudden positive pulse. Therefore, based on the changes in impedance and total thermal energy, the impedance change rate of each data point is extracted, completing the transformation from "mixed signal observation" to "feature signal separation", laying the foundation for subsequent precise filtering of thermal drift and inductive reactance interference at the algorithm level. The thermal resistance reference represents the inherent, normal thermal response rate of the wire harness material itself. By comparing the impedance change rate with the thermal resistance reference, the constant background that is contributed by the normal temperature rise of the material and occupies the main component of the signal is removed, and the slip characteristic value of each data point is obtained to highlight the slip positive pulse in the residual signal, which directly supports the high sensitivity and high reliability of defect detection targets.
[0043] Preferably, in one embodiment of the present invention, for each data point, the difference between the impedance of the analyzed data point and the impedance of the adjacent previous data point is used as the numerator, and the difference between the total heat energy of the analyzed data point and the total heat energy of the adjacent previous data point is used as the denominator, and the ratio of the fractions is used as the impedance change rate of the analyzed data point.
[0044] Since resampling is performed on the energy axis with a preset energy step size, the denominator must not be zero; the current corresponding to the first data point is small, the wire harness is in the initial cold state, the thermal stress has not yet been established, and theoretically there will be no micro-slip driven by thermal expansion, so the impedance change rate is set to 0.
[0045] Further baseline correction of the impedance change rate was performed using thermal resistance as a reference, and negative values were truncated to obtain the slip characteristic value of each data point.
[0046] As an example, slip eigenvalues The calculation formulas include: ; in, This represents the slip characteristic value of the nth data point; This represents the function that takes the maximum value. This represents the rate of change of impedance at the nth data point; Indicates thermal resistance reference; By subtracting the material's inherent thermal resistance reference from the rate of change of impedance, baseline correction is completed, eliminating significant thermal drift background; if A negative value indicates that the impedance change at the corresponding time is mainly dominated by the inductive reactance effect. The result is much less than zero; if Although positive, it is less than or close to This indicates that the impedance change is mainly caused by the normal temperature rise of the material. The result is zero or a tiny positive value. (Using...) The function truncates negative values, which can be applied to both cases. The result is forced to zero, thereby automatically filtering out inductive interference and suppressing background fluctuations caused by normal temperature rise, ultimately making Only positive abrupt change signals that are significantly greater than zero caused by mechanical slip are retained in the sequence, thus achieving pure extraction of slip features.
[0047] Step S3: Obtain the slip determination threshold based on the distribution of slip feature values within the optimal linear region; generate test results based on the slip determination threshold and the slip feature values of the entire process data.
[0048] To avoid poor adaptability to different wire harness specifications due to the use of fixed thresholds based on experience, a slip judgment threshold is adaptively set according to the distribution of slip characteristic values within the optimal linear region. Finally, test results are generated based on the slip judgment threshold and the slip characteristic values of the entire process data. The test results avoid the tediousness and uncertainty of manually adjusting the threshold, significantly improve the robustness and adaptability of the detection system, and ensure the objectivity of the quality judgment standard.
[0049] Preferably, in one embodiment of the present invention, the wire harness in the optimal linear region is in a thermoelastic stable state and theoretically there is no mechanical slippage. The slippage characteristic value calculated in this interval is mainly composed of the white noise and quantization error of the measurement system. Therefore, the mean and standard deviation of the slippage characteristic value in the optimal linear region are fused to obtain the slippage judgment threshold.
[0050] As an example, the mean of the slip eigenvalues within the optimal linear region is added to three times the standard deviation, and the sum is used as the slip threshold. This threshold represents the maximum statistical probability boundary of the signal deviating from the zero baseline under the current testing environment and equipment accuracy. Any abrupt change exceeding this magnitude is considered a non-random physical event (i.e., slip).
[0051] Search in chronological order, mark the index of the first data point whose first consecutive preset length of slip characteristic value is greater than the slip judgment threshold as the invalid index, and leave the flag empty if not found. (If a failure index exists) Extract the failure critical current corresponding to the failure index, compare the failure critical current with the preset qualified current, or generate test results based on the status of the flag bit.
[0052] As an example, with a preset length of 3, power supply ripple or sampling interference may cause single-point spikes. Continuity judgment can effectively filter out non-physical slip noise. When the slip characteristic value is greater than the slip judgment threshold for the first time, it indicates that a continuous and stable mechanical slip event has occurred. At this time, the index of the first data point of this continuous slip characteristic value is marked as the failure index, for example, n, n+1, n+2. n is marked as the failure index, and the current of the data point of the failure index is used as the failure critical current. If it is not found, it means that no detectable slip has occurred during the entire test process, and it is marked as NULL.
[0053] When the flag is empty, or the failure critical current is not less than the preset qualified current, it indicates that there is no slippage throughout the entire process, or although there is slight slippage, it occurs in the high current limit area, which meets the engineering margin requirements. The product is judged to be qualified, and the system outputs a "PASS" signal, and the test ends.
[0054] When the failure critical current is less than the preset qualified current, it indicates that the structure has become loose before the rated load is reached. The product is judged as unqualified, and the system outputs a "FAIL" signal, displays the specific value of the failure critical current, and prompts the operator to check the pressing height or mold wear.
[0055] In this example, the preset qualified current is the maximum test current. The value is d times the value of the wire harness, where d is the quality safety factor, which is set to 0.9. This means that the wire harness must be able to withstand at least 90% of the full-scale current without slippage.
[0056] It should be noted that the state of the flag bit is not considered when a critical failure current exists; in other embodiments of the present invention, the implementer may adjust the preset length and quality safety factor according to actual needs.
[0057] One embodiment of the present invention also provides an electrical performance testing device for vehicle wiring harnesses; please refer to [link to relevant documentation]. Figure 2 The diagram shows a schematic of the electrical performance testing device for vehicle wiring harnesses provided in an embodiment of the present invention. The device includes a data acquisition module 101, an analysis module 102, and a judgment module 103.
[0058] The acquisition module 101 is used to acquire test data of the vehicle wiring harness under constant slope current excitation; the test data is resampled based on a preset energy step size to obtain the current, voltage and total heat energy injected into the wiring harness to be analyzed, and the impedance of each data point is acquired.
[0059] Analysis module 102 is used to slide a preset sliding window across the entire process data, analyze the linear relationship between impedance and total energy within the window after each slide, and obtain the optimal linear region; extract the slope of the regression line between impedance and total energy within the optimal linear region, and obtain the thermal resistance benchmark by combining it with a preset heat dissipation correction factor; extract the impedance change rate of each data point based on the changes in impedance and total heat energy; and obtain the sliding characteristic value of each data point by comparing the impedance change rate with the thermal resistance benchmark.
[0060] The judgment module 103 is used to obtain the slip judgment threshold based on the distribution of slip feature values within the optimal linear region; and to generate test results based on the slip judgment threshold and the slip feature values of the whole process data.
[0061] The implementation process of modules 101-103 has been described in the electrical performance testing method of vehicle wiring harness described in steps S1-S3, and will not be repeated here.
[0062] An embodiment of the present invention also provides an electrical performance testing device for vehicle wiring harnesses. The device includes a memory, a processor, and a computer program. The memory is used to store the corresponding computer program, and the processor is used to run the corresponding computer program. When the computer program runs in the processor, it can implement the electrical performance testing method for vehicle wiring harnesses described in steps S1-S3.
[0063] In summary, to address the technical problem of low detection accuracy caused by thermal drift and inductive interference masking weak slip signals, this invention provides a method, apparatus, and equipment for testing the electrical performance of automotive wiring harnesses. This invention first acquires test data under constant slope current excitation, then resamples the data to be analyzed based on a preset energy step size; further, it identifies the optimal linear region, extracts the slope of the regression line between impedance and total energy within this region, and obtains the thermal resistance benchmark; it further extracts the impedance change rate at each data point, compares the impedance change rate with the thermal resistance benchmark, and obtains the slip characteristic value for each data point; further, it obtains the slip judgment threshold based on the distribution of the slip characteristic values within the optimal linear region; finally, it generates test results based on the slip judgment threshold and the slip characteristic values of the entire process data. This invention, through constant slope excitation and energy domain analysis, adaptively extracts the thermal resistance benchmark and calculates slip characteristics, thereby achieving accurate slip detection under strong thermal drift and inductive interference, solving the problems of missed detections and misjudgments in traditional methods.
[0064] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.
[0065] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.
Claims
1. A method for testing the electrical performance of an automotive wiring harness, characterized in that, The method includes: Acquire test data of the vehicle wiring harness under constant slope current excitation; resample the test data based on a preset energy step size to obtain the current, voltage and total heat energy injected into the wiring harness to be analyzed, and obtain the impedance of each data point; A preset sliding window is slid across the entire data process. The linear relationship between the impedance and the total energy within the window after each slide is analyzed to obtain the optimal linear region. The slope of the regression line between the impedance and the total energy is extracted within the optimal linear region, and a thermal resistance benchmark is obtained by combining it with a preset heat dissipation correction factor. The impedance change rate of each data point is extracted based on the changes in impedance and the changes in total heat energy. The sliding characteristic value of each data point is obtained by comparing the impedance change rate with the thermal resistance benchmark. Based on the distribution of the slip feature values within the optimal linear region, a slip determination threshold is obtained; based on the slip determination threshold and the slip feature values of the entire process data, a test result is generated.
2. The method for testing the electrical performance of a vehicle wiring harness according to claim 1, characterized in that, The method for obtaining the optimal linear region includes: For each sliding window, a univariate linear regression analysis is performed on the impedance and the total energy to obtain the coefficient of determination; based on the coefficient of determination, the optimal linear region is selected.
3. The method for testing the electrical performance of a vehicle-mounted wiring harness according to claim 1, characterized in that, The method for obtaining the slip feature value includes: The impedance change rate is baseline-corrected and truncated to negative values using the thermal resistance reference to obtain the slip characteristic value of each data point.
4. The method for testing the electrical performance of a vehicle wiring harness according to claim 1, characterized in that, The method for obtaining the slip determination threshold includes: The mean and standard deviation of the slip characteristic values within the optimal linear region are combined to obtain the slip determination threshold.
5. The method for testing the electrical performance of a vehicle wiring harness according to claim 1, characterized in that, The methods for obtaining the test results include: Search in chronological order, mark the index of the first data point whose first consecutive preset length of the slip characteristic value is greater than the slip determination threshold as an invalid index, and leave the flag empty if not found. Extract the critical failure current corresponding to the failure index, compare the critical failure current with the preset qualified current, or generate test results based on the status of the flag bit.
6. The method for testing the electrical performance of an on-board wiring harness according to claim 5, characterized in that, Methods for generating test results by comparing the failure critical current with a preset qualified current, or based on the state of the flag bit, include: When the flag bit is empty, or the failure critical current is not less than the preset qualified current, the product is judged to be qualified. When the failure critical current is less than the preset qualified current, the product is determined to be unqualified.
7. The method for testing the electrical performance of an on-board wiring harness according to claim 1, characterized in that, The linear relationship between the impedance and the total energy is analyzed based on the least squares method.
8. The method for testing the electrical performance of a vehicle wiring harness according to claim 1, characterized in that, The length of the preset sliding window is 10% of the total data points to be analyzed, and the sliding step is half the length of the window.
9. An electrical performance testing device for vehicle wiring harnesses, characterized in that, The device includes: The acquisition module is used to acquire test data of the vehicle wiring harness under constant slope current excitation; the test data is resampled based on a preset energy step size to obtain the current, voltage and total heat energy injected into the wiring harness to be analyzed, and the impedance of each data point is acquired. The analysis module is used to slide a preset sliding window across the entire process data, analyze the linear relationship between the impedance and the total energy within the window after each slide, and obtain the optimal linear region; extract the slope of the regression line between the impedance and the total energy within the optimal linear region, and obtain the thermal resistance benchmark by combining it with a preset heat dissipation correction factor; extract the impedance change rate for each data point based on the changes in impedance and the changes in total heat energy; and compare the impedance change rate with the thermal resistance benchmark to obtain the sliding characteristic value of each data point. The determination module is used to obtain a slip determination threshold based on the distribution of the slip feature values within the optimal linear region; and to generate test results based on the slip determination threshold and the slip feature values of the whole process data.
10. An electrical performance testing device for vehicle wiring harnesses, the device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the electrical performance testing method for a vehicle wiring harness as described in any one of claims 1 to 8.