Automobile wire harness wire insulation sheath damage detection method and system

Abstract

The invention relates to the technical field of automobile electrical detection, provides an automobile wire harness wire insulation skin damage detection method and system, and aims to solve the technical problem that a certain loop insulation skin damage position point is difficult to find in the prior art. Comprising a plane capacitance sensor used for measuring capacitance change between the plane capacitance sensor and a to-be-measured wire harness to obtain a charge signal used for representing the damage state of an insulating material of the to-be-measured wire harness; the charge amplifier is used for performing voltage conversion and amplification processing on the charge signal to obtain a voltage signal; the impedance analyzer is used for calculating impedance through the voltage signal and the current signal, drawing a Bode diagram based on the obtained impedance, and performing index parameter extraction on the Bode diagram to obtain various index parameters; and the upper computer is used for carrying out feature extraction on the multiple index parameters to obtain feature data, and analyzing the damage state of the insulating material of the wire harness to be detected according to the feature data to obtain a detection result.

Description

Technical Field

[0001] The present invention belongs to the technical field of automobile electrical detection, and in particular relates to a method and system for detecting insulation damage of automobile wiring harness conductors. Background Art

[0002] With the continuous development of automobile technology, cars have more and more functions, and the number of wire loops in automobile wiring harnesses has also increased. The probability of automobile failures caused by wire loop problems has increased significantly. Among the after-sales problems of these automobile failures, short circuit and crosstalk problems caused by damaged wire insulation account for a considerable proportion. However, automobile wiring harness branches are spread throughout the entire car body, each branch is wrapped with tape, and there are dozens or even hundreds of loops in it. It is very difficult to find the location of the damaged insulation of a certain loop using traditional methods, which brings great inconvenience to after-sales maintenance. Summary of the Invention

[0003] The present invention provides a method and system for detecting insulation damage of automotive wiring harness conductors, aiming to solve the technical problem in the prior art that it is difficult to find the location point where the insulation of a certain loop is damaged.

[0004] The present invention solves the above-mentioned technical problem with the following technical solution: a system for detecting insulation damage of an automotive wiring harness conductor, the system comprising: A planar capacitance sensor, used to measure a capacitance change between the planar capacitance sensor and the wiring harness to be tested, and obtain a charge signal for characterizing a damage state of an insulating material of the wiring harness to be tested; a charge amplifier, configured to convert the charge signal into a voltage and amplify the voltage to obtain a voltage signal; An impedance analyzer is configured to collect a current signal flowing through the wiring harness to be tested in real time through a configured current sensor, calculate impedance based on the voltage signal and the current signal, draw a Bode diagram based on the obtained impedance, and extract index parameters from the Bode diagram to obtain multiple index parameters; The host computer is used to extract features of multiple index parameters to obtain feature data, and analyze the damage state of the insulation material of the wiring harness to be tested based on the feature data to obtain a test result.

[0005] Furthermore, the above-mentioned planar capacitive sensor includes: an excitation electrode, configured to generate a disturbance in a detection electric field between the planar capacitive sensor and the wiring harness to be measured after being excited by the planar capacitive sensor; The sensing electrode is used to sense the change in capacitance between the planar capacitance sensor and the wiring harness to be measured according to the change in the detection electric field.

[0006] Furthermore, the excitation electrode and the sensing electrode are arranged on the same plane.

[0007] Furthermore, the charge amplifier comprises: an amplifying unit, configured to convert the charge signal into a voltage and amplify the voltage to obtain an initial voltage signal; The output buffer unit is used to convert the initial voltage signal from high impedance to low impedance to obtain a voltage signal.

[0008] Furthermore, the impedance analyzer comprises: A signal generating unit, configured to generate a continuous sine wave and continuously change the frequency of the sine wave based on a preset target frequency band to obtain an excitation signal; The synchronous measurement unit is connected to the signal unit and is used to collect the amplitude information and phase angle of the current signal and the voltage signal at each frequency point of the excitation signal, and perform complex processing to obtain a complex voltage representation and a complex current representation. The calculation formula of the complex voltage representation is shown as follows:

[0009] Among them, |V| represents the amplitude information of the voltage signal, j represents the imaginary number, θ v represents the voltage phase angle; The calculation formula for complex current representation is as follows:

[0010] Among them, |I| represents the amplitude information of the current signal, j represents the imaginary number, θ I represents the current phase angle; The impedance curve drawing unit is used to calculate the complex impedance at each frequency point based on Ohm's law, and summarize the complex impedance at all frequency points to obtain a Bode plot. The formula for calculating the complex impedance is shown below:

[0011] Where Z represents the complex impedance; The parameter quantization unit is used to extract index parameters from the Bode diagram to obtain multiple index parameters; wherein the index parameters include: quality factor, dissipation factor, self-resonant frequency and high-frequency impedance slope change trend.

[0012] Furthermore, the host computer includes: a preprocessing unit, configured to receive the indicator parameters and perform noise elimination and interference removal processing on the indicator parameters to obtain preprocessed data; A feature extraction unit, configured to identify abnormal mutation points on the preprocessed data to obtain feature data; The analysis unit is used to perform feature matching on the feature data against a preset damage database to obtain a damage type, and locate the damage position based on the damage type.

[0013] Furthermore, the host computer further includes: A visualization unit is used to visually display the damaged position.

[0014] Furthermore, the host computer further includes: A monitoring unit, configured to monitor the state and state changes of the planar capacitive sensor in real time; The visualization unit is connected to the monitoring unit and is further used to visually display the state and state changes of the planar capacitive sensor in real time.

[0015] In a second aspect, the present invention further provides a method for detecting insulation damage of an automotive wiring harness conductor, which is used in the above-mentioned automotive wiring harness conductor insulation damage detection system, and the method comprises: Acquiring a charge signal representing a damage state of the insulation material of the wiring harness to be tested; wherein the charge signal is measured using a planar capacitance sensor; Performing voltage conversion and amplification processing on the charge signal to obtain a voltage signal; The current signal flowing through the wiring harness to be tested is collected in real time by a configured current sensor, and the impedance is calculated based on the voltage signal and the current signal, and a Bode diagram is drawn based on the obtained impedance; Extracting index parameters from the Bode diagram to obtain multiple index parameters; Feature extraction is performed on a plurality of index parameters to obtain feature data, and the damage state of the insulation material of the wiring harness to be tested is analyzed based on the feature data to obtain a test result.

[0016] Furthermore, the above judgment on whether the detection result is that the wiring harness is damaged: If yes, the feature data is matched with a preset damage database to obtain a damage type, and the damage position is located based on the damage type; If not, the output is that the wiring harness is normal.

[0017] Compared with the prior art, the present invention has the following advantages: 1. The present invention forms a highly focused detection electric field by arranging the excitation electrode and the sensing electrode of the planar capacitive sensor in the same plane, which can capture micron-level insulation layer defects on the surface of the wiring harness.

[0018] 2. The output buffer unit of the present invention converts high-impedance charge signals into low-impedance voltage signals, effectively suppressing electromagnetic interference and improving signal-to-noise ratio.

[0019] 3. The present invention obtains the impedance-frequency curve through the impedance analyzer and combines it with the feature extraction algorithm of the host computer to identify the capacitance change caused by damage, thereby locating the damage position.

[0020] 4. The pre-processing unit of the present invention eliminates temperature drift through baseline calibration to ensure stable detection under complex working conditions.

[0021] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 A schematic structural diagram of a system for detecting insulation damage of a wire harness in an automobile according to an embodiment of the present invention is shown; Figure 2 A schematic structural diagram of a planar capacitive sensor according to an embodiment of the present invention is shown; Figure 3 shows a schematic structural diagram of a charge amplifier according to an embodiment of the present invention; Figure 4 A schematic structural diagram of an impedance analyzer according to an embodiment of the present invention is shown; Figure 5 It shows a schematic structural diagram of a host computer according to an embodiment of the present invention; Figure 6 A flow chart of a method for detecting insulation damage of a wire in an automobile wiring harness according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0025] Figure 1FIG. 1 shows a schematic structural diagram of a system for detecting insulation damage of an automotive wiring harness conductor according to an embodiment of the present invention. Figure 1 As shown, a system for detecting insulation damage of an automotive wiring harness conductor according to an embodiment of the present invention includes: A planar capacitance sensor, used to measure a capacitance change between the planar capacitance sensor and the wiring harness to be tested, and obtain a charge signal for characterizing a damage state of an insulating material of the wiring harness to be tested; a charge amplifier, configured to convert the charge signal into a voltage and amplify the voltage to obtain a voltage signal; An impedance analyzer is configured to collect a current signal flowing through the wiring harness to be tested in real time through a configured current sensor, calculate impedance based on the voltage signal and the current signal, draw a Bode diagram based on the obtained impedance, and extract index parameters from the Bode diagram to obtain multiple index parameters; The host computer is used to extract features of multiple index parameters to obtain feature data, and analyze the damage state of the insulation material of the wiring harness to be tested based on the feature data to obtain a test result.

[0026] In summary, in this embodiment, the coplanar arrangement of the excitation and sensing electrodes of the planar capacitive sensor creates a highly focused detection electric field, enabling the capture of micron-scale insulation defects on the surface of the wiring harness. The output buffer unit of the charge amplifier converts the high-impedance charge signal into a low-impedance voltage signal, effectively suppressing electromagnetic interference and improving the signal-to-noise ratio. By acquiring the impedance-frequency curve using an impedance analyzer and combining it with the feature extraction algorithm of the host computer, the capacitance changes caused by damage can be identified, thereby locating the damage location.

[0027] Optionally, the planar capacitive sensor includes: an excitation electrode, configured to generate a disturbance in a detection electric field between the planar capacitive sensor and the wiring harness to be measured after being excited by the planar capacitive sensor; The sensing electrode is used to sense the change in capacitance between the planar capacitance sensor and the wiring harness to be measured according to the change in the detection electric field.

[0028] In this embodiment, the wiring harness to be tested is placed above the planar capacitance sensor, and a variable capacitance structure is formed between the two. When the wiring harness conductor is excited by an alternating voltage, the state of its external insulation material will directly affect the effective dielectric constant and distributed capacitance value of the capacitance structure. If the insulation layer is damaged, aged, or has partial discharge, it will cause abnormal changes in the capacitance between the sensor and the wiring harness. Figure 2 As shown, the planar capacitance sensor detects the capacitance change and outputs a corresponding charge signal Q, which is used to represent the integrity status of the wiring harness insulation material.

[0029] Optionally, the excitation electrode and the sensing electrode are arranged coplanarly.

[0030] Optional, such as Figure 3 As shown, the charge amplifier includes: an amplifying unit, configured to convert the charge signal into a voltage and amplify the voltage to obtain an initial voltage signal; In this embodiment, the amplification unit is an operational amplifier (Op-Amp) with high input impedance. When the charge signal produces a small charge change, the charge is fed back to the feedback capacitor (Feedback Capacitor, C f The operational amplifier detects this charge change and converts it into a corresponding voltage change output. The formula is V out =− , where Q represents the charge, C f Indicates the value of the feedback capacitor.

[0031] The output buffer unit is used to convert the initial voltage signal from high impedance to low impedance to obtain a voltage signal.

[0032] In this embodiment, the output buffer unit adopts a voltage follower. The initial voltage signal is pre-amplified and filtered to improve the signal-to-noise ratio and adapt to the input requirements of subsequent measurement equipment. The output voltage signal V out The dynamic information of the original capacitance change is retained, reflecting the temporal and spatial variation trend of the insulation status of the wiring harness.

[0033] Optional, such as Figure 4 As shown, the impedance analyzer includes: A signal generating unit, configured to generate a continuous sine wave and continuously change the frequency of the sine wave based on a preset target frequency band to obtain an excitation signal; The synchronous measurement unit is connected to the signal unit and is used to collect the amplitude information and phase angle of the current signal and the voltage signal at each frequency point of the excitation signal, and perform complex processing to obtain a complex voltage representation and a complex current representation. The calculation formula of the complex voltage representation is shown as follows:

[0034] Among them, |V| represents the amplitude information of the voltage signal, j represents the imaginary number, θ v represents the voltage phase angle; The calculation formula for complex current representation is as follows:

[0035] Among them, |I| represents the amplitude information of the current signal, j represents the imaginary number, θ I represents the current phase angle; The impedance curve drawing unit is used to calculate the complex impedance at each frequency point based on Ohm's law, and summarize the complex impedance at all frequency points to obtain a Bode plot. The formula for calculating the complex impedance is shown below:

[0036] Where Z represents the complex impedance; The parameter quantization unit is used to extract index parameters from the Bode diagram to obtain multiple index parameters; wherein the index parameters include: quality factor, dissipation factor, self-resonant frequency and high-frequency impedance slope change trend.

[0037] Optional, such as Figure 5 As shown, the host computer includes: a preprocessing unit, configured to receive the indicator parameters and perform noise elimination and interference removal processing on the indicator parameters to obtain preprocessed data; In this embodiment, digital filtering (such as FIR and wavelet denoising) is used to eliminate high-frequency noise.

[0038] A feature extraction unit, configured to identify abnormal mutation points on the preprocessed data to obtain feature data; In this embodiment, the abnormal mutation points include resonance frequency shift and Q value drop.

[0039] The analysis unit is used to perform feature matching on the feature data against a preset damage database to obtain a damage type, and locate the damage position based on the damage type.

[0040] In this embodiment, the extracted feature data is matched and compared with a preset damage database, which contains impedance response templates of various typical insulation defects. The features are intelligently identified by combining machine learning classification models (such as support vector machines (SVMs) and convolutional neural networks (CNNs)), and the damage type and its confidence level are output. The damage position is preliminarily located based on the spatial mapping relationship between phase change and impedance distribution.

[0041] In this embodiment, feature matching is performed through a machine learning model, and the matching results are output. Then, the damage position is located through a spatial positioning algorithm, which includes a time difference method (TDOA) of a multi-sensor array or a capacitance field distribution inversion algorithm.

[0042] In this embodiment, the abnormal mutation point identification of the pre-processed data is specifically performed as follows: multi-scale feature extraction: Low-frequency analysis: In the low-frequency region (e.g., 1kHz to 100kHz), the impedance exhibits primarily capacitive behavior, decreasing with increasing frequency and exhibiting a negative phase. Unusually flat or steep slopes in this region may indicate insulation material aging or localized defects.

[0043] High-frequency analysis: At high frequencies (e.g., above 1 MHz), parasitic inductance becomes significant, with impedance increasing with frequency and the phase shifting to a positive value. Sudden changes in the high-frequency band may indicate a break in the insulation layer or an exposed metal core.

[0044] Slope mutation detection: Calculate the local slope change of the impedance curve using a sliding window method to identify whether there is a mutation point. If a certain slope deviates significantly from the normal trend, it is marked as a potential damage area.

[0045] Optionally, the host computer further includes: A visualization unit is used to visually display the damaged position.

[0046] In this embodiment, the electric field intensity on the surface of the harness is displayed by a color gradient, which intuitively indicates the damaged area.

[0047] Optionally, the host computer further includes: A monitoring unit, configured to monitor the state and state changes of the planar capacitive sensor in real time; The visualization unit is connected to the monitoring unit and is further used to visually display the state and state changes of the planar capacitive sensor in real time.

[0048] In this embodiment, the host computer can also automatically adjust the sweep frequency range, sampling rate or excitation amplitude of the impedance analyzer according to the current detection results to achieve dynamic optimization of the detection process; the system can be connected to external environmental sensors (such as temperature and humidity sensors) to compensate for temperature drift of the impedance data, further improving the detection stability and repeatability.

[0049] In this embodiment, the host computer displays the test results in a graphical interface, including the original Bode plot, feature extraction curves, damage type and location information, etc. When severe insulation damage is identified, an audible and visual alarm is triggered, and a remote notification can be sent via the network interface to alert operators to take timely action.

[0050] Based on Figure 1 The same principle as the method shown in , the embodiment of the present invention also provides a method for detecting insulation damage of automobile wiring harness wires, such as Figure 6 As shown in , including: Acquiring a charge signal representing a damage state of the insulation material of the wiring harness to be tested; wherein the charge signal is measured using a planar capacitance sensor; Performing voltage conversion and amplification processing on the charge signal to obtain a voltage signal; The current signal flowing through the wiring harness to be tested is collected in real time by a configured current sensor, and the impedance is calculated based on the voltage signal and the current signal, and a Bode diagram is drawn based on the obtained impedance; Extracting index parameters from the Bode diagram to obtain multiple index parameters; Feature extraction is performed on a plurality of index parameters to obtain feature data, and the damage state of the insulation material of the wiring harness to be tested is analyzed based on the feature data to obtain a test result.

[0051] Optionally, determining whether the detection result indicates that the wiring harness is damaged: If yes, the feature data is matched with a preset damage database to obtain a damage type, and the damage position is located based on the damage type; If not, the output is that the wiring harness is normal.

[0052] It should be understood that the flowcharts and block diagrams in the accompanying drawings illustrate the possible implementation architecture, functions and operations of the methods and computer program products according to various embodiments of the present invention. In this regard, each box in the flowchart or block diagram can represent a module, program segment, or a part of code, and the module, program segment, or a part of code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order than the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of the boxes in the block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or can be implemented using a combination of dedicated hardware and computer instructions.

[0053] The above description is merely a preferred embodiment of the present invention and an illustration of the technical principles employed. Those skilled in the art should understand that the scope of disclosure involved in the present invention is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but also includes other technical solutions formed by any combination of the above-mentioned technical features or their equivalents without departing from the above-mentioned disclosed concepts. For example, a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features with similar functions disclosed in the present invention.

Claims

1. A system for detecting insulation damage of automotive wiring harness wires, characterized in that: The system comprises: A planar capacitance sensor, used to measure a capacitance change between the planar capacitance sensor and the wiring harness to be tested, and obtain a charge signal for characterizing a damage state of an insulating material of the wiring harness to be tested; a charge amplifier, configured to convert the charge signal into a voltage and amplify the voltage to obtain a voltage signal; An impedance analyzer is configured to collect a current signal flowing through the wiring harness to be tested in real time through a configured current sensor, calculate impedance based on the voltage signal and the current signal, draw a Bode diagram based on the obtained impedance, and extract index parameters from the Bode diagram to obtain multiple index parameters; The host computer is used to extract features of multiple index parameters to obtain feature data, and analyze the damage state of the insulation material of the wiring harness to be tested based on the feature data to obtain a test result.

2. The automotive wiring harness wire insulation damage detection system according to claim 1, characterized in that: The planar capacitive sensor comprises: an excitation electrode, configured to generate a disturbance in a detection electric field between the planar capacitive sensor and the wiring harness to be measured after being excited by the planar capacitive sensor; The sensing electrode is used to sense the change in capacitance between the planar capacitance sensor and the wiring harness to be measured according to the change in the detection electric field.

3. The automotive wiring harness wire insulation damage detection system according to claim 2, characterized in that: The excitation electrode and the sensing electrode are arranged coplanarly.

4. The automotive wiring harness wire insulation damage detection system according to claim 1, characterized in that: The charge amplifier comprises: an amplifying unit, configured to convert the charge signal into a voltage and amplify the voltage to obtain an initial voltage signal; The output buffer unit is used to convert the initial voltage signal from high impedance to low impedance to obtain a voltage signal.

5. The automotive wiring harness wire insulation damage detection system according to claim 1, characterized in that: The impedance analyzer comprises: A signal generating unit, configured to generate a continuous sine wave and continuously change the frequency of the sine wave based on a preset target frequency band to obtain an excitation signal; The synchronous measurement unit is connected to the signal unit and is used to collect the amplitude information and phase angle of the current signal and the voltage signal at each frequency point of the excitation signal, and perform complex processing to obtain a complex voltage representation and a complex current representation. The calculation formula of the complex voltage representation is shown as follows: Among them, |V| represents the amplitude information of the voltage signal, j represents the imaginary number, θ v Indicates the voltage phase angle; The calculation formula for complex current representation is as follows: Among them, |I| represents the amplitude information of the current signal, j represents the imaginary number, θ I represents the current phase angle; The impedance curve drawing unit is used to calculate the complex impedance at each frequency point based on Ohm's law, and summarize the complex impedance at all frequency points to obtain a Bode plot. The formula for calculating the complex impedance is shown below: Where Z represents the complex impedance; The parameter quantization unit is used to extract index parameters from the Bode diagram to obtain multiple index parameters; wherein the index parameters include: quality factor, dissipation factor, self-resonant frequency and high-frequency impedance slope change trend.

6. The automotive wiring harness wire insulation damage detection system according to claim 1, characterized in that: The host computer includes: a preprocessing unit, configured to receive the indicator parameters and perform noise elimination and interference removal processing on the indicator parameters to obtain preprocessed data; A feature extraction unit, configured to identify abnormal mutation points on the preprocessed data to obtain feature data; The analysis unit is used to perform feature matching on the feature data against a preset damage database to obtain a damage type, and locate the damage position based on the damage type.

7. The automotive wiring harness wire insulation damage detection system according to claim 6, characterized in that: The host computer also includes: A visualization unit is used to visually display the damaged position.

8. The automotive wiring harness wire insulation damage detection system according to claim 7, characterized in that: The host computer also includes: A monitoring unit, configured to monitor the state and state changes of the planar capacitive sensor in real time; The visualization unit is connected to the monitoring unit and is further used to visually display the state and state changes of the planar capacitive sensor in real time.

9. A method for detecting insulation damage of automotive wiring harness wires, characterized in that: A system for detecting insulation damage of an automotive wiring harness conductor according to any one of claims 1 to 8, the method comprising: Acquiring a charge signal representing a damage state of the insulation material of the wiring harness to be tested; wherein the charge signal is measured using a planar capacitance sensor; Performing voltage conversion and amplification processing on the charge signal to obtain a voltage signal; The current signal flowing through the wiring harness to be tested is collected in real time by a configured current sensor, and the impedance is calculated based on the voltage signal and the current signal, and a Bode diagram is drawn based on the obtained impedance; Extracting index parameters from the Bode diagram to obtain multiple index parameters; Feature extraction is performed on a plurality of index parameters to obtain feature data, and the damage state of the insulation material of the wiring harness to be tested is analyzed based on the feature data to obtain a test result.

10. The method for detecting insulation damage of an automobile wiring harness conductor according to claim 9, characterized in that: Determine whether the detection result indicates that the wiring harness is damaged: If yes, the feature data is matched with a preset damage database to obtain a damage type, and the damage position is located based on the damage type; If not, the output is that the wiring harness is normal.

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