A vehicle wire harness conduction test system and method based on human body antenna effect
The automotive wiring harness continuity testing system based on the human antenna effect utilizes human body induction signals for contactless signal acquisition and FFT analysis, solving the problems of cumbersome operation and contact reliability in traditional testing methods, and achieving efficient and accurate wiring harness testing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HEBI HAICHANG SPECIAL EQUIP
- Filing Date
- 2026-03-04
- Publication Date
- 2026-06-26
AI Technical Summary
Traditional automotive wiring harness continuity testing methods are cumbersome to operate, have poor contact reliability, and lack equipment adaptability, resulting in low production efficiency and low accuracy, making it difficult to meet diverse testing needs.
A test system based on the human antenna effect is adopted. It utilizes the alternating electric field signal in the space sensed by the human body, and realizes continuity testing without hard connection or contact with metal through signal acquisition, amplification, filtering, analog-to-digital conversion and FFT analysis. Combined with an automatic gain calibration module, it can be adapted to different human bodies and environments.
Significantly reduces manual operation, improves testing efficiency and accuracy, adapts to wiring harnesses of different vehicle models, fits into large-scale assembly line production, and enhances equipment flexibility and consistency of test results.
Smart Images
Figure CN122283532A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of automotive wiring harness testing technology, and particularly relates to an automotive wiring harness continuity testing system and method based on the human antenna effect. Background Technology
[0002] Automotive wiring harnesses are the "network core" of automotive circuits, connecting all electrical components of a car, such as the engine, headlights, and sensors. Their conductivity directly determines the operational stability of the automotive electrical system. If a wiring harness has an open circuit, it can cause malfunctions such as lights going out or sensors failing. Therefore, strict conductivity testing is required during the production of wiring harnesses.
[0003] Traditional automotive wiring harness continuity testing methods rely on constructing a physical conductive circuit, mainly divided into two types: one is to connect one end of the wiring harness to the "common ground" of the test equipment via a wire, and connect the other end to the test probe; the other is to let the terminal at the other end of the wiring harness directly touch the metal ground connected to the common ground, such as the grounding metal plate on the surface of the test bench, and finally determine the continuity of the wiring harness by detecting the current or voltage parameters in the circuit.
[0004] The aforementioned traditional testing methods have several significant drawbacks: First, the operation process is cumbersome. For multi-core wire harnesses, it is necessary to perform hard connection to the common ground or grounding operation for each wire individually. This is especially true for complex wire harnesses such as automotive main wiring harnesses, which contain hundreds of wires. This significantly increases the workload for workers, easily leads to worker fatigue, and reduces production and testing efficiency. Second, the contact reliability is poor. Hard connection is prone to introducing contact resistance due to loose connections, and terminal touching to ground is prone to poor contact due to insufficient contact pressure or metal surface oxidation. Both of these situations will interfere with the test results and reduce the accuracy of the test. Third, the equipment has limited adaptability. The specifications of wire harnesses vary greatly among different vehicle models. During the test, it is necessary to frequently change the common ground wiring fixture or adjust the grounding position. The equipment lacks flexibility and is difficult to match diverse testing needs.
[0005] The automotive manufacturing industry is currently transforming towards high efficiency and intelligence. The market urgently needs more convenient and efficient automotive wiring harness testing equipment and methods to reduce manual operations, improve the consistency of test results, and thus help improve the production capacity and optimize the quality control level of automotive wiring harness production. Summary of the Invention
[0006] To address the shortcomings of existing technologies, the present invention aims to provide an automotive wiring harness continuity testing system and method based on the human antenna effect, which simplifies the testing process, improves the efficiency and reliability of wiring harness continuity testing, and solves the problems in the background technology.
[0007] This invention provides the following technical solution: A continuity testing system for automotive wiring harnesses based on the human antenna effect, comprising: The signal acquisition unit is used to come into contact with the human body and acquire the weak electrical signals generated by the alternating electric field in the space sensed by the human body. The signal amplification and filtering unit is electrically connected to the signal acquisition unit and performs adjustable gain amplification and target frequency narrowband filtering on the weak electrical signal. The analog-to-digital conversion unit is electrically connected to the signal amplification and filtering unit, and converts the filtered and amplified analog electrical signal into a digital signal and transmits it externally. The processing unit is electrically connected to the analog-to-digital conversion unit and is equipped with an FFT IP core to perform a fast Fourier transform on the digital signal, analyze the amplitude change of the target frequency component, and determine the conduction status of the vehicle wiring harness. The display and prompt unit is electrically connected to the processing unit, and displays the test results and outputs corresponding audio-visual prompts; An automatic gain calibration module is electrically connected to the signal amplification and filtering unit and the processing unit, and automatically adjusts the amplification gain of the signal amplification and filtering unit according to the initial signal strength sensed by the human body.
[0008] Preferably, the signal acquisition unit uses a conductive probe, which is made of copper or an alloy and has an anti-oxidation treatment on its surface.
[0009] Preferably, the signal amplification and filtering unit includes an adjustable gain amplifier circuit and an active bandpass filter circuit; the total amplification gain range of the adjustable gain amplifier circuit is 1000-10000 times, and it is built by a multi-stage operational amplifier; the center frequency of the active bandpass filter circuit is 50Hz, and it is an RC active bandpass filter; the processing unit is selected from FPGA processing units or STM series microcontrollers.
[0010] Preferably, the analog-to-digital conversion unit uses an analog-to-digital conversion chip with a resolution of 12 bits or higher, the sampling rate of the analog-to-digital conversion chip is ≥1kHz, and it supports an SPI communication interface to transmit digital signals to the FPGA processing unit through the SPI interface.
[0011] Preferably, the FPGA processing unit uses a Xilinx series FPGA chip, and the FFTIP core is configured through Vivado software, with 1024 or 2048 FFT operation points. The FPGA processing unit determines the conduction state by comparing the amplitude change of the target frequency signal under open circuit and test conditions. When the amplitude change exceeds a preset threshold, it is determined to be conducting. The preset threshold is obtained through experimental calibration.
[0012] Preferably, the target frequency is 50Hz, and the preset threshold is 20% of the reference amplitude of the 50Hz signal under the open-circuit state of the harness.
[0013] Preferably, the display and prompting unit includes a display module and an audio-visual prompting module; the display module is an LCD or TFT LCD display screen, used to display the target frequency signal amplitude, signal spectrum diagram and conduction determination result; the audio-visual prompting module includes LED lights of at least two colors and a buzzer, which outputs the test result through a combination of light and sound.
[0014] Preferably, the automatic gain calibration module controls the analog switch to switch the feedback resistor of the amplifier circuit through the FPGA processing unit to adjust the gain, so that the amplitude of the induced signal under different human bodies and different environments is stabilized within the preset standard range.
[0015] Preferably, a method for testing the continuity of automotive wiring harnesses includes the following steps: Step 1: System initialization and automatic gain calibration. After the test system is powered on and initialized, the human body touches the signal acquisition unit. The automatic gain calibration module acquires the initial signal strength and automatically adjusts the amplification gain of the signal amplification and filtering unit to make the signal amplitude approach the preset standard. Step 2: Prepare for wiring harness testing. Insert the terminals of the vehicle wiring harness to be tested into the corresponding test holes on the test bench. There is no need to hard-connect to the common ground or touch the metal ground. Step 3: Signal Acquisition and Conversion. The human body remains in contact with the signal acquisition unit, which collects the weak electrical signals sensed by the human body. After being amplified and filtered by the signal amplification and filtering unit, the signals are converted into digital signals by the analog-to-digital conversion unit and transmitted to the FPGA processing unit. Step 4: FFT analysis and conduction determination. The FPGA processing unit calls the FFT IP core to perform a fast Fourier transform on the digital signal, extracts the amplitude of the target frequency component and calculates the change in amplitude compared with the open circuit reference amplitude. The conduction status of the harness is then determined by comparing the change with a preset threshold. Step 5: Result display and prompts. The display and prompts unit receives the judgment result from the FPGA processing unit, displays the test data in real time, and outputs the corresponding audio-visual prompts.
[0016] Preferably, in step 3, the spatial alternating electric field is a 50Hz mains alternating electric field, and the sampling rate of the analog-to-digital conversion unit is configured to 10kHz, satisfying the Nyquist sampling criterion; in step 4, the time-domain digital signal is converted into a frequency-domain signal through fast Fourier transform to achieve high-precision amplitude analysis at the 50Hz frequency point.
[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a continuity testing system and method for automotive wiring harnesses based on the human antenna effect. By utilizing the human antenna effect to achieve signal acquisition, it eliminates the need for hard-connecting the automotive wiring harness to a common ground or touching a metal ground, significantly reducing the amount of manual operation required for multi-core and complex wiring harnesses, avoiding worker fatigue, and significantly improving the efficiency of automotive wiring harness production and testing, thus adapting to the needs of large-scale assembly line production.
[0018] It abandons the traditional hard connection and grounding contact method, fundamentally avoiding the interference of contact resistance and poor contact on the test results. At the same time, it achieves high-precision extraction of target signals through signal amplification and filtering and FFT frequency domain analysis, further improving the accuracy and consistency of test results.
[0019] There is no need to frequently change wiring fixtures or adjust grounding positions according to the wiring harness specifications of different car models. It can be adapted to the testing of automotive wiring harnesses of different specifications and models. At the same time, the automatic gain calibration module can be adapted to different human users and different environmental usage scenarios, greatly improving the flexibility and adaptability of the equipment.
[0020] The system and method of this invention are in line with the transformation direction of the automotive manufacturing industry towards efficiency and intelligence. The overall system structure is simple, the hardware selection is conventional, the testing methods and steps are clear and easy to operate, and workers can be easily trained and mastered. It is convenient to promote and apply it in the industrialization of automotive wiring harness manufacturing enterprises, and help enterprises improve their production capacity and quality control level. Attached Figure Description
[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.
[0022] Figure 1 This is a block diagram of the needle structure of the testing system of the present invention.
[0023] Figure 2 This is a schematic diagram of the signal amplification and filtering unit circuit of the present invention.
[0024] Figure 3 This is a flowchart of the FPGA processing unit FFTIP core configuration and data processing of the present invention. Detailed Implementation
[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 a part of the embodiments of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0026] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.
[0027] like Figure 1-3 As shown, a continuity testing system for automotive wiring harnesses based on the human antenna effect is described. The hardware selection and connection methods of each unit in the testing system are as follows: Signal acquisition unit: It adopts a copper conductive probe with an anti-oxidation treatment on the surface. The probe diameter is 8mm and the contact end is rounded to reduce the contact resistance between the human body and the probe and improve the comfort of human contact. The output end of the conductive probe is electrically connected to the input end of the signal amplification and filtering unit.
[0028] Signal amplification and filtering unit: The amplification circuit uses a TLV272 operational amplifier to build a multi-stage amplification circuit, including an instrumentation operational amplifier and a non-inverting amplifier circuit, with a total amplification gain range of 1000-10000 times; the active bandpass filter circuit uses an LMV324 operational amplifier to form an RC active bandpass filter with a center frequency of 50Hz, a quality factor Q=10, and a bandwidth of 5Hz, allowing only signals near 50Hz to pass through, accurately filtering out environmental electromagnetic noise and circuit noise; the input terminal of the amplification circuit is connected to the signal acquisition unit, the output terminal is connected to the bandpass filter circuit, and the output terminal of the bandpass filter circuit is connected to the analog-to-digital converter unit.
[0029] Analog-to-digital conversion unit: It adopts a 12-bit resolution ADC128S102 chip, and the reference voltage adopts a high-precision reference source REF5025 (2.5V) to ensure the accuracy of analog-to-digital conversion; the chip supports SPI communication interface, and the actual configuration sampling rate is 10kHz, which meets the Nyquist sampling criterion for 50Hz signals; the analog signal input terminal of the chip is connected to the signal amplification and filtering unit, and the SPI communication interface is bidirectionally electrically connected to the SPI interface of the FPGA processing unit.
[0030] FPGA processing unit: The Xilinx Spartan-7 series XC7S50 chip is used. The FFT IP core is configured using Xilinx Vivado 2021.2 software. The number of FFT operation points is set to 1024, the input data bit width is 12 bits, the output data bit width is 16 bits, and the clock frequency is 50MHz. Pipeline mode is enabled to improve the FFT operation speed. The chip's SPI interface is connected to the analog-to-digital converter unit, and the GPIO pins are electrically connected to the analog switch of the signal amplification and filtering unit, and the display and prompt unit, respectively. The preset threshold of the 50Hz signal amplitude is determined to be 20% of the open-circuit reference value through experimental calibration, and the threshold parameter is pre-stored in the FPGA chip.
[0031] Display and prompt unit: The display module uses a 1.8-inch TFT LCD screen, supports SPI communication interface, and is connected to the SPI interface of the FPGA processing unit to display the 50Hz signal amplitude, spectrum diagram and conduction determination result; the sound and light prompt module includes a green LED, a red LED and a passive buzzer, all three of which are electrically connected to the GPIO pins of the FPGA processing unit and are directly driven by the FPGA chip.
[0032] Automatic gain calibration module: It consists of an FPGA processing unit and an analog switch and feedback resistor of the signal amplification and filtering unit. The analog switch is connected to the feedback resistor of the amplification circuit. The FPGA processing unit controls the switching of the analog switch to switch different feedback resistors to realize automatic adjustment of the amplification gain. The system has a preset standard value of 0~2V for the signal amplitude. During the calibration process, the amplitude of the induced signal is stabilized within this range.
[0033] As one possible implementation method, the specific steps for performing a continuity test on an automotive wiring harness are as follows: Step 1: System initialization and automatic gain calibration. Connect the test bench to the regulated DC power supply. After each unit of the system is powered on and initialized, it enters the test state after a self-test without faults. The worker touches the copper conductive probe of the signal acquisition unit with his hand. The automatic gain calibration module acquires the initial weak 50Hz electrical signal induced by the human body. The FPGA processing unit, based on the initial signal strength acquired by the ADC128S102, controls the analog switch to switch the feedback resistor of the amplifier circuit and automatically adjusts the amplification gain to stabilize the amplitude of the induced signal within the preset standard value of 0-2V, thus completing the gain calibration. Step 2: Preparation for wiring harness testing. The worker inserts the terminals of the automotive wiring harness to be tested one by one into the corresponding test holes on the test bench to complete the positioning of the wiring harness. The entire process does not require any hard connection to the common ground or contact with metal grounding of the automotive wiring harness. Step 3: Signal Acquisition and Conversion. The worker maintains contact between their hand and the copper conductive probe. The 50Hz alternating electric field of the human body sensing room generates a weak signal at the microvolt level, which is acquired by the copper conductive probe. This weak signal is transmitted to the signal amplification and filtering unit, amplified 1000-10000 times by an amplification circuit composed of TLV272 operational amplifiers, and then filtered out for noise by a 50Hz active bandpass filter composed of LMV324. The amplified and filtered analog signal is transmitted to the ADC128S102 chip, which converts the analog signal into a 12-bit digital signal. The digital signal is then transmitted to the XC7S50 FPGA chip via the SPI interface at a sampling rate of 10kHz. Step 4: FFT Analysis and Conductivity Determination. The XC7S50 FPGA chip calls the pre-configured 1024-point FFT IP core to perform a Fast Fourier Transform on the received digital signal, converting the time-domain signal into a frequency-domain signal. The FPGA chip extracts the amplitude of the 50Hz component in the frequency domain and compares this amplitude with the reference amplitude of the 50Hz signal in the open-circuit state of the harness, calculating the amplitude change. If the amplitude change exceeds 20% of the reference value, the harness under test is determined to be conductive; otherwise, the harness under test is determined to be non-conductive. Specifically, the FFT analysis and conduction determination process, centered on an FPGA, consists of five consecutive steps: FFTIP core pre-configuration, digital signal reception, time-frequency domain conversion, 50Hz frequency point amplitude extraction, and conduction state determination. It involves converting the time-domain electrical signal transmitted by the ADC into frequency-domain feature values, and then determining the conduction state through feature value comparison. The details are as follows: FFTIP core pre-configuration During the power-on initialization of the test system, the parameters of the FFT IP core were configured using the IP Integrator in the Vivado software. The core parameters were fixed as follows: transform length of 1024 points, input data bit width of 12 bits (matching the resolution of ADC128S102), output data bit width of 16 bits, clock frequency of 50MHz, and pipelined mode was enabled to improve the computing speed. This configuration lays the foundation for high-precision frequency domain analysis of 50Hz signals, and a single configuration can be applied to all subsequent test processes.
[0034] Digital signal reception The FPGA receives digital signals transmitted by the analog-to-digital converter (ADC) unit through the SPI interface. The ADC sampling rate is configured to 10kHz (≥1kHz, satisfying the Nyquist sampling criterion for 50Hz signals) to ensure that the acquired time-domain signals are free of aliasing and can truly reflect the characteristics of electrical signals sensed by the human body.
[0035] Time-frequency domain transformation (FFT operation) The FPGA calls the pre-configured FFT IP core to perform a fast Fourier transform on the received 1024-point time-domain digital signal, converting the time-domain electrical signal that originally varied with time into a frequency-domain signal with frequency as the horizontal axis and amplitude as the vertical axis. This enables feature extraction of the signal from the "time dimension" to the "frequency dimension." The core purpose is to accurately separate the signal at the 50Hz target frequency point and filter out noise interference at other frequencies.
[0036] 50Hz frequency point amplitude extraction The FPGA performs a modulo operation on the frequency domain data output by the FFT operation to calculate the signal amplitude corresponding to each frequency point. Then, based on the sampling rate and the FFT transform length, the target frequency point of 50Hz is located, and the amplitude data of this frequency point is extracted as the core feature value for subsequent conduction determination.
[0037] Conductivity determination The FPGA extracts the 50Hz real-time amplitude and compares it with the system's pre-stored open-circuit reference amplitude of the wiring harness to calculate the amplitude change. If the change exceeds the preset threshold of the experimental calibration (20% of the reference value), the wiring harness is determined to be conductive. If the change does not reach the preset threshold and the open-circuit reference amplitude characteristics are maintained, the wiring harness is determined to be non-conductive. The determination result is transmitted to the display and prompt unit in real time.
[0038] The amplitude change is calculated with the open-circuit reference amplitude of the harness as a reference, and is a relative change (in percentage form). The calculation process is completed automatically by the FPGA without human intervention, ensuring the accuracy and consistency of the calculation. The specific calculation formula and related definitions are as follows: Core parameter definition A0: Open circuit reference amplitude of the wiring harness (a fixed value pre-stored after system calibration) The amplitude of the 50Hz frequency point extracted by the FPGA after the test system has completed automatic gain calibration and no wiring harness is connected (or the wiring harness is completely open) serves as the reference benchmark for all subsequent tests. It is determined by experimental calibration and stored in the FPGA.
[0039] A1: Real-time amplitude of wire harness test; This refers to the real-time amplitude of the 50Hz frequency point extracted by the FPGA through FFT analysis after the wiring harness under test is connected.
[0040] ΔA%: Relative change in amplitude (core indicator, in percentage form); Threshold S: Preset judgment threshold, fixed at 20% (experimental calibration value).
[0041] The amplitude change is calculated using a relative rate of change to avoid the slight influence of factors such as human skin resistance and environmental humidity on the absolute amplitude, thus improving the robustness of the judgment. The formula is: ΔA%=|(A1-A0) / A0|*100%; Formula explanation: Taking the absolute value is to avoid the case of a small decrease in amplitude. Only the relative change of amplitude is considered. Regardless of whether A1 increases or decreases relative to A0, as long as the rate of change reaches the threshold, it is determined to be on.
[0042] Determination threshold The calculated ΔA% is compared with the preset threshold S (20%), and the judgment rule is as follows: If ΔA% > S (20%), the harness is conducting; If ΔA%≤S(20%), the harness is not conducting.
[0043] Step 5: Result Display and Prompt. The FPGA chip transmits the continuity determination result to the display and prompt unit. The 1.8-inch TFT LCD screen displays the amplitude of the 50Hz signal, the signal spectrum, and the text test result of "Continuous" or "Not Continuous" in real time. At the same time, if it is determined to be continuous, the FPGA chip drives the green LED to light up and the buzzer to sound briefly once; if it is determined to be not continuous, the FPGA chip drives the red LED to light up and the buzzer to sound for 3 seconds. The worker can quickly obtain the test result according to the sound and light prompts and complete a continuity test of the automotive wiring harness.
[0044] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can be modified and varied in various ways. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A continuity testing system for automotive wiring harnesses based on the human antenna effect, characterized in that, include: The signal acquisition unit is used to come into contact with the human body and acquire the weak electrical signals generated by the alternating electric field in the space sensed by the human body. The signal amplification and filtering unit is electrically connected to the signal acquisition unit and performs adjustable gain amplification and target frequency narrowband filtering on the weak electrical signal. The analog-to-digital conversion unit is electrically connected to the signal amplification and filtering unit, and converts the filtered and amplified analog electrical signal into a digital signal and transmits it externally. The processing unit is electrically connected to the analog-to-digital conversion unit and is equipped with an FFT IP core to perform a fast Fourier transform on the digital signal, analyze the amplitude change of the target frequency component, and determine the conduction status of the vehicle wiring harness. The display and prompt unit is electrically connected to the processing unit, and displays the test results and outputs corresponding audio-visual prompts; An automatic gain calibration module is electrically connected to the signal amplification and filtering unit and the processing unit, and automatically adjusts the amplification gain of the signal amplification and filtering unit according to the initial signal strength sensed by the human body.
2. The automotive wiring harness continuity testing system based on the human antenna effect according to claim 1, characterized in that, The signal acquisition unit uses a conductive probe, which is made of copper or an alloy and has an anti-oxidation treatment on its surface.
3. The automotive wiring harness continuity testing system based on the human antenna effect according to claim 1, characterized in that, The signal amplification and filtering unit includes an adjustable gain amplifier circuit and an active bandpass filter circuit; the total amplification gain range of the adjustable gain amplifier circuit is 1000-10000 times, and it is built by a multi-stage operational amplifier; the center frequency of the active bandpass filter circuit is 50Hz, and it is an RC active bandpass filter; the processing unit is selected from FPGA processing units or STM series microcontrollers.
4. The automotive wiring harness continuity testing system based on the human antenna effect according to claim 1, characterized in that, The analog-to-digital conversion unit uses an analog-to-digital conversion chip with a resolution of 12 bits or higher. The sampling rate of the analog-to-digital conversion chip is ≥1kHz, and it supports an SPI communication interface to transmit digital signals to the processing unit through the SPI interface.
5. The automotive wiring harness continuity testing system based on the human antenna effect according to claim 3, characterized in that, The FPGA processing unit uses Xilinx series FPGA chips and is configured with an FFTIP core via Vivado software. The number of FFT operation points is 1024 or 2048. The FPGA processing unit determines the conduction state by comparing the amplitude change of the target frequency signal under open circuit and test conditions. When the amplitude change exceeds a preset threshold, it is determined to be conducting. The preset threshold is obtained through experimental calibration.
6. The automotive wiring harness continuity testing system based on the human antenna effect according to claim 5, characterized in that, The target frequency is 50Hz, and the preset threshold is 20% of the reference amplitude of the 50Hz signal under the open-circuit state of the harness.
7. The automotive wiring harness continuity testing system based on the human antenna effect according to claim 1, characterized in that, The display and prompting unit includes a display module and an audio-visual prompting module; the display module is an LCD or TFT LCD screen used to display the target frequency signal amplitude, signal spectrum diagram and conduction determination result; the audio-visual prompting module includes LEDs of at least two colors and a buzzer, which outputs the test result through a combination of light and sound.
8. The automotive wiring harness continuity testing system based on the human antenna effect according to claim 1, characterized in that, The automatic gain calibration module uses the FPGA processing unit to control the analog switch to switch the feedback resistor of the amplifier circuit to adjust the gain, so that the amplitude of the induced signal under different human bodies and different environments is stabilized within the preset standard range.
9. A method for testing the continuity of an automotive wiring harness based on the system described in any one of claims 1-8, characterized in that, Includes the following steps: Step 1: System initialization and automatic gain calibration. After the test system is powered on and initialized, the human body touches the signal acquisition unit. The automatic gain calibration module acquires the initial signal strength and automatically adjusts the amplification gain of the signal amplification and filtering unit to make the signal amplitude approach the preset standard. Step 2: Prepare for wiring harness testing. Insert the terminals of the vehicle wiring harness to be tested into the corresponding test holes on the test bench. There is no need to hard-connect to the common ground or touch the metal ground. Step 3: Signal Acquisition and Conversion. The human body remains in contact with the signal acquisition unit, which collects the weak electrical signals sensed by the human body. After being amplified and filtered by the signal amplification and filtering unit, the signals are converted into digital signals by the analog-to-digital conversion unit and transmitted to the FPGA processing unit. Step 4: FFT analysis and conduction determination. The FPGA processing unit calls the FFTIP core to perform a fast Fourier transform on the digital signal, extracts the amplitude of the target frequency component and calculates the change in amplitude compared with the open circuit reference amplitude. The conduction status of the harness is then determined by comparing the change with a preset threshold. Step 5: Result display and prompts. The display and prompts unit receives the judgment result from the FPGA processing unit, displays the test data in real time, and outputs the corresponding audio-visual prompts.
10. The automotive wiring harness continuity testing method according to claim 9, characterized in that, In step 3, the spatial alternating electric field is a 50Hz mains alternating electric field, and the sampling rate of the analog-to-digital conversion unit is configured to 10kHz, satisfying the Nyquist sampling criterion; in step 4, the time-domain digital signal is converted into a frequency-domain signal through fast Fourier transform, realizing high-precision amplitude analysis at the 50Hz frequency point.