A kind of automobile wire harness lossless conduction and accurate pullback integrated test system and method

Abstract

The application discloses a kind of automobile wire harness lossless conduction and accurate pullback integrated test system and method, it is related to automobile wire harness detection technical field.System includes main control processing unit, and the detection module, at least one group of pullback execution mechanism and man-machine interaction unit respectively with main control processing unit connection;Detection module built-in sheath locking mechanism and conduction contact probe with displacement detection function, pullback execution mechanism integrates wire harness clamping assembly, closed-loop drive execution unit and carrier signal emission unit.The application transmits carrier signal that can penetrate wire harness insulating skin by non-contact coupling mode, realizes single-end lossless conduction test without hard connection, without terminal damage;In pullback process, carrier signal continuity and tension data are monitored synchronously, and the integration of real-time determination of conduction and pullback is completed.The application improves test reliability and production efficiency, reduces labor intensity, and can adapt to automobile wire harness large-scale production demand in all scenarios.

Description

Technical Field

[0001] This invention belongs to the field of automotive wiring harness testing technology, and particularly relates to an integrated testing system and method for non-destructive continuity and precise pull-back of automotive wiring harnesses. Background Technology

[0002] Automotive wiring harnesses are the core transmission carriers of the vehicle's electrical system, undertaking the critical functions of power transmission and signal interaction. The reliability of the connection between the wiring harness terminals and sheaths, as well as the wiring harness's conductivity, directly determine the operational stability and driving safety of the entire vehicle's electrical system. In the mass production of wiring harnesses, after each wiring harness completes terminal crimping and sheath insertion, it must undergo two core tests: first, a continuity test to verify that the terminal insertion hole positions are correct and that the wiring harness has no open circuits; second, a pull-back test to verify that the locking force between the terminals and sheath meets the standards, preventing terminals from coming loose during use and causing malfunctions.

[0003] In existing technologies, automotive wiring harness testing solutions suffer from three major, insurmountable pain points: First, continuity testing suffers from fundamental technical limitations. Traditional continuity testing relies on a hard connection at both ends to form an electrical circuit. One end of the wiring harness must be connected to the test power supply, and the other end hard-connected to a common ground / ground to determine continuity. This process is cumbersome, and frequent plugging and unplugging can damage the terminal plating, affecting product quality. Furthermore, hard connections are prone to introducing testing errors due to poor contact, making it impossible to monitor continuity in real-time during pull-back and accurately capture the critical state of terminal disengagement. Existing non-destructive testing solutions can only achieve continuity detection in specific scenarios, cannot be deeply integrated with pull-back testing, and are highly restrictive in terms of hardware selection, resulting in a very narrow protection scope. This makes them easily circumvented by competitors by replacing components.

[0004] Secondly, the accuracy and efficiency of pull-back testing cannot be simultaneously achieved. Traditional manual pull-back testing relies on workers applying force manually, which is prone to errors such as pulling multiple wires or testing non-target wire harnesses. It often results in misjudgments based solely on sheath displacement, leading to a high false positive rate. Furthermore, manual pulling force cannot be precisely controlled, resulting in insufficient force causing missed detections or excessive force damaging products. Continuous operation also increases the risk of hand fatigue and occupational diseases for workers, and the slow testing cycle time at a single workstation severely restricts production line capacity. Existing automated pull-back equipment can only perform mechanical pull-back actions and cannot simultaneously complete continuity testing. It requires multiple separate devices, resulting in high production line investment costs and the inability to achieve accurate independent testing of individual wire harnesses.

[0005] Third, the solution has poor adaptability and cannot meet the needs of large-scale production lines. Existing integrated testing equipment can only be adapted to wire harnesses and sheaths of specific specifications, and cannot quickly switch between testing products with different wire diameters, different tensile strength requirements, and different sheath specifications; moreover, it does not support multi-station parallel expansion, cannot match the insertion and connection work rhythm of production line workers, and is difficult to promote and apply in large-scale production lines. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide an integrated testing system and method for non-destructive continuity and precise pull-back of automotive wiring harnesses. This system achieves a testing solution that enables single-end non-destructive continuity, simultaneous determination of continuity and pull-back, wide applicability, and clear protection boundaries. It solves the problems of low accuracy, poor efficiency, and cumbersome operation in existing technologies, thereby resolving the issues in the background technology.

[0007] This invention provides the following technical solution: An integrated testing system for non-destructive continuity and precise pull-back of automotive wiring harnesses includes a main control processing unit, detection modules electrically connected to the main control processing unit, at least one set of pull-back actuators, and a human-machine interaction unit. The detection module includes a sheath locking mechanism and a conductive contact probe with displacement detection function. The sheath locking mechanism is used to position and fix the sheath of the wire harness under test. The conductive contact probe is used to contact the wire harness terminal inserted into the sheath, receive the carrier signal transmitted by the wire harness, and collect the displacement data of the probe and transmit it to the main control processing unit. The pull-back actuator includes a wire harness clamping assembly, a closed-loop controllable drive execution unit, and a carrier signal transmitting unit. The wire harness clamping assembly is used to clamp and fix the non-plug-in ends of the wire harness under test. The drive execution unit is connected to the wire harness clamping assembly and is used to drive the wire harness clamping assembly to perform the tightening and pull-back actions of the wire harness, and to feed back the tension, torque, and stroke data to the main control processing unit in real time. The carrier signal transmitting unit is used to transmit a carrier signal that can penetrate the wire harness insulation to the wire harness under test through non-contact coupling, without the need for a hard connection with the wire harness core or the formation of a double-ended hard-connection electrical circuit. The main control processing unit is used to perform test logic judgment based on the received carrier signal, probe displacement data, tension, torque and stroke data, and output control commands to each module; The human-computer interaction unit is used for configuring test parameters, displaying test results, and providing device status prompts.

[0008] Preferably, the carrier signal transmitting unit adopts any one or more combinations of amplitude shift keying, frequency shift keying, and phase shift keying carrier modulation technology. The carrier signal operates in the frequency band of 10kHz-1MHz and can penetrate the wire harness insulation sheath with a thickness of 0.2mm-5mm to form a coupled signal loop with the wire harness core.

[0009] Preferably, the sheath locking mechanism adopts any one of pneumatic locking, electric locking, and hydraulic locking, with a locking positioning accuracy of not less than ±0.5mm, and can be adapted to wire harness sheaths of different shapes and hole specifications.

[0010] Preferably, the drive execution unit adopts any one of servo motor, stepper motor, linear motor, and pneumatic servo actuator, with a tension control range of 2N-200N and a stroke control accuracy of not less than 0.5mm. It supports user-defined settings for tension / torque test thresholds and stroke protection upper limits.

[0011] Preferably, the conductive contact probe integrates a contact or non-contact displacement sensing unit with a displacement detection accuracy of not less than 0.05 mm; the main control processing unit presets a qualified probe displacement range, and only when the probe displacement data is within the qualified range is it determined that the terminal and probe are in reliable contact, and the pull-back test process is started.

[0012] Preferably, the test logic judgment rule of the main control processing unit is as follows: during the pull-back test, the continuity of the carrier signal and the pull / torque data of the drive execution unit are monitored in real time; if the interruption duration of the carrier signal reaches the preset interruption threshold, it is immediately determined that the terminal is disconnected and the test fails, and the drive execution unit is controlled to stop operating and reset; if the output pull / torque of the drive execution unit reaches the preset test threshold and the carrier signal is continuous without interruption throughout the process, it is immediately determined that both the conduction and pull-back tests are passed, and the drive execution unit is controlled to reset.

[0013] Preferably, it also includes a cascaded communication interface, which is connected to the main control processing unit and adopts any one of the following communication methods: industrial bus, Ethernet, and wireless communication. It supports at least 32 groups of pullback actuators to be cascaded at the same time, and the main control processing unit can perform independent addressing, independent control, and parallel synchronous testing on each group of pullback actuators.

[0014] Preferably, the wire harness clamping assembly adopts any one of roller clamping, claw clamping, or clamping clamping, and the clamping contact surface is provided with an anti-slip and friction-enhancing structure, which can accommodate wires with a diameter of 0.3mm. 2 -10mm 2 The automotive wiring harness is clamped and fixed.

[0015] Preferably, the main control processing unit has a built-in storage module that can store at least 1,000 sets of test parameter templates for wire harness specifications. It can also record and store all test process data and result data in real time, and support integration with the production line MES system and ERP system to achieve full-process quality traceability of wire harness testing.

[0016] Preferably, a method for integrated testing of non-destructive continuity and precise pull-back in automotive wiring harnesses includes the following steps: S1 parameter configuration: Configure the corresponding test parameters according to the specifications of the wire harness under test, including tensile test threshold, stroke protection upper limit, carrier signal parameters, and carrier interruption judgment threshold; S2 Sheath Fixing and Wire Harness Insertion: Position and lock the sheath of the wire harness to be tested, insert the wire harness terminal into the corresponding hole of the sheath, so that the terminal contacts the conductive contact probe, and at the same time clamp and fix the non-plug-in end of the wire harness. S3 Single-Ended Non-Destructive Continuity Pre-Detection: A carrier signal that can penetrate the insulation of the wire harness is emitted to the wire harness under test through non-contact coupling. There is no need to make a hard connection with the wire harness core or form a double-ended hard connection electrical circuit. The carrier signal is received by the continuity contact probe to determine the basic continuity status of the wire harness. At the same time, the contact reliability between the terminal and the probe is verified by the displacement data of the probe. S4 Integrated Pull-back Test and Real-time Monitoring: After the continuity pre-detection and contact verification are passed, the wire harness is tightened at a preset speed to perform a pull-back test. During the test, tension / torque data is collected in real time, and the continuity of the carrier signal is continuously monitored. S5 Test Result Judgment: If the carrier signal interruption duration reaches the preset interruption threshold, the terminal is deemed to have come off and the test has failed; if the pulling force reaches the preset test threshold and the carrier signal is continuous and uninterrupted throughout the entire process, both the conduction and pull-back tests are deemed to have passed.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses an integrated testing system and method for non-destructive continuity and precise pull-back of automotive wiring harnesses. Through non-contact carrier coupling technology, the carrier signal penetrates the wiring harness insulation and forms a coupling loop with the wire core. This eliminates the need for a hard connection to a common ground / ground at the other end of the wiring harness, avoids damage to the insulation layer, and eliminates the need for double-ended wiring. It completely solves the pain point of traditional continuity testing that relies on hard connection loops, avoids damage to the terminal plating caused by hard connection insertion and removal, and greatly simplifies the testing operation process, perfectly adapting to the insertion operation rhythm of the wiring harness production line.

[0018] By deeply integrating continuity testing and pull-back testing, the terminal connection status is monitored in real time through the continuity of the carrier signal during the pull-back process. This can accurately capture the critical state of terminal disengagement, completely solving the industry pain point of manual testing involving multiple lines pulling and misjudging the pass / fail status. At the same time, the pull force is precisely controlled through the closed-loop control drive execution unit, which not only ensures the effectiveness of the test, but also avoids excessive pulling that could damage the product.

[0019] The testing process is fully automated, requiring only workers to perform wire harness insertion and placement without the need for continuous manual pulling back, thus completely eliminating hand fatigue and occupational diseases. Simultaneously, it supports cascaded parallel testing of multiple pull-back actuators, enabling synchronous operation of "current wire harness testing - next wire harness insertion." The testing cycle time per workstation can be reduced to 1 / 4 of traditional manual testing, significantly improving production line efficiency and perfectly meeting the needs of large-scale automotive wire harness production.

[0020] It is compatible with testing of all types of automotive wiring harnesses with different wire diameters, sheath specifications, and tensile strength requirements. It supports one-click switching of multiple specification parameter templates and can quickly adapt to production line changeover needs. At the same time, it supports parallel expansion of multiple workstations and can flexibly connect with existing production lines without large-scale modification of production line layout. The production line investment cost is low and it has strong industrialization and promotion value. 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 schematic diagram of the execution flow of the test system of the present invention. Detailed Implementation

[0023] 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, and 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.

[0024] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of protection of the present invention, but merely to illustrate selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0025] Example 1: like Figure 1 As shown, an integrated testing system for non-destructive continuity and precise pull-back of automotive wiring harnesses includes a main control processing unit, detection modules electrically connected to the main control processing unit, at least one set of pull-back actuators, and a human-machine interaction unit. The detection module includes a sheath locking mechanism and a conductive contact probe with displacement detection function. The sheath locking mechanism is used to position and fix the sheath of the wire harness under test. The conductive contact probe is used to contact the wire harness terminal inserted into the sheath, receive the carrier signal transmitted by the wire harness, and collect the displacement data of the probe and transmit it to the main control processing unit. The pull-back actuator includes a wire harness clamping assembly, a closed-loop controllable drive execution unit, and a carrier signal transmitting unit. The wire harness clamping assembly is used to clamp and fix the non-plug-in ends of the wire harness under test. The drive execution unit is connected to the wire harness clamping assembly and is used to drive the wire harness clamping assembly to perform the tightening and pull-back actions of the wire harness, and to feed back the tension, torque, and stroke data to the main control processing unit in real time. The carrier signal transmitting unit is used to transmit a carrier signal that can penetrate the wire harness insulation to the wire harness under test through non-contact coupling, without the need for a hard connection with the wire harness core and without the need to form a double-ended hard-connection electrical circuit. The main control processing unit is used to perform test logic judgment based on the received carrier signal, probe displacement data, tension, torque and stroke data, and output control commands to each module; The human-computer interaction unit is used for configuring test parameters, displaying test results, and providing device status prompts.

[0026] The carrier signal transmitting unit adopts any one or more combinations of amplitude shift keying, frequency shift keying, and phase shift keying carrier modulation technology. The carrier signal operates in the frequency band of 10kHz-1MHz and can penetrate the wire harness insulation sheath with a thickness of 0.2mm-5mm to form a coupled signal loop with the wire harness core.

[0027] The sheath locking mechanism can be any one of pneumatic locking, electric locking, or hydraulic locking, with a locking positioning accuracy of not less than ±0.5mm, and can be adapted to wire harness sheaths of different shapes and hole specifications.

[0028] The drive actuator can be any one of a servo motor, stepper motor, linear motor, or pneumatic servo actuator. The tension control range is 2N-200N, the stroke control accuracy is not less than 0.5mm, and it supports user-defined settings for tension / torque test thresholds and stroke protection upper limits.

[0029] The conductive contact probe integrates a contact or non-contact displacement sensing unit with a displacement detection accuracy of not less than 0.05mm. The main control processing unit has a preset probe displacement qualified range. Only when the probe displacement data is within the qualified range is it determined that the terminal and probe are in reliable contact, and the pull-back test process is started.

[0030] The test logic judgment rule of the main control processing unit is as follows: During the pullback test, the continuity of the carrier signal and the pull / torque data of the drive execution unit are monitored in real time; if the interruption duration of the carrier signal reaches the preset interruption threshold, it is immediately determined that the terminal is disconnected and the test fails, and the drive execution unit is controlled to stop the operation and reset; if the output pull / torque of the drive execution unit reaches the preset test threshold and the carrier signal is continuous without interruption throughout the process, it is immediately determined that both the conduction and pullback tests are passed, and the drive execution unit is controlled to reset.

[0031] It also includes a cascading communication interface, which is connected to the main control processing unit and adopts any one of the following communication methods: industrial bus, Ethernet, or wireless communication. It supports at least 32 groups of pullback actuators to be cascaded at the same time. The main control processing unit can perform independent addressing, independent control, and parallel synchronous testing on each group of pullback actuators.

[0032] The wire harness clamping assembly adopts any one of the following types: roller clamping, claw clamping, and clamp clamping. The clamping contact surface is equipped with an anti-slip and friction-enhancing structure, which can accommodate wires with a diameter of 0.3mm. 2 -10mm 2 Automotive wiring harness.

[0033] The main control processing unit has a built-in storage module that can store at least 1,000 sets of test parameter templates for wire harness specifications. It can also record and store all test process data and results data in real time, and supports integration with the production line MES system and ERP system to achieve full-process quality traceability of wire harness testing.

[0034] Example 2: An integrated testing system for non-destructive continuity and precise pull-back of automotive wiring harnesses, compatible with wire diameters of 0.3mm. 2 -6mm 2 The test system is designed for conventional automotive low-voltage wiring harnesses with a rated pull-back force of 5N-50N. It includes a main control processing unit, a detection module electrically connected to the main control processing unit, a set of pull-back actuators, and a human-machine interface unit.

[0035] The main control processing unit uses an STM32F407ZGT6 microcontroller as its core MCU. This MCU has a 32-bit Cortex-M4 core, a clock frequency of 168MHz, and integrates three 12-bit ADC acquisition channels, six UART communication interfaces, and 14 timer peripherals. The main control processing unit is also equipped with a W25Q128JV SPI Flash external memory and a DS3231 real-time clock module. The minimum system of the main control processing unit is equipped with an 8MHz passive crystal oscillator and a 32.768kHz RTC crystal oscillator. The reset circuit uses an RC low-pass filter combined with a manual reset button. The BOOT0 and BOOT1 pins are pulled down to ground and configured for flash boot mode. The MCU's PA0 pin is connected to the signal output of the tension sensor via a second-order RC low-pass filter circuit, and the PA1 pin is connected to the signal output of the probe displacement sensor via a filter circuit of the same specification. The ADC reference voltage uses a REF3033 3.3V precision reference source. The PB6 and PB7 pins are configured as I2C interfaces. The communication pins of the carrier signal transmitting unit are connected; PA9 and PA10 are configured as USART1 interfaces to connect to the human-machine interaction unit; PD0-PD3 pins are isolated by TLP521 optocouplers and connected to the pulse, direction, enable, and alarm pins of the servo motor driver, respectively; PE0-PE2 pins are driven by ULN2003 Darlington transistors and connected to the sheath locking cylinder solenoid valve, roller clamping solenoid valve, and audible and visual alarm module, respectively; PB0 pin is configured as a pull-down input and connected to the signal output pin of the carrier module for real-time detection of the continuity of the carrier signal.

[0036] In this embodiment, the power module uses a Mean Well LRS-150-24 type 24V / 6.5A DC switching power supply as the main power supply to power the servo motor and cylinder solenoid valve, and is equipped with a 10A self-resetting fuse and TVS surge protection circuit. The 24V main power supply is converted to 5V DC power supply by LM2596S-5V type step-down chip to power the human-machine interaction unit, carrier module and sensor. The 5V power supply is converted to 3.3V DC power supply by AMS1117-3.3V type linear regulator chip to power the main control MCU, external memory and reference source. Each power supply is equipped with a filter circuit consisting of a 100μF electrolytic capacitor and a 0.1μF ceramic capacitor.

[0037] The detection module includes a sheath locking mechanism and a conductive contact probe with displacement detection function. The sheath locking mechanism uses an Airtac TCL16×15-S pneumatic cylinder with a magnetic ring position sensor, with a stroke of 15mm. A nylon pressure block is fitted to the end of the cylinder push rod. The cylinder is fixed to the side of the positioning cavity of the detection module. When the cylinder extends, the pressure block presses against the side of the sheath to achieve positioning and locking, with a positioning accuracy of ±0.2mm. The positioning cavity can be quickly replaced to adapt to different specifications of sheaths. The magnetic ring sensor is installed at the end of the cylinder stroke; when the cylinder is fully extended, it outputs a magnetic ring. A high-level locking confirmation signal is output; the conductive contact probe adopts the Huarong HR-100B gold-plated test probe with a head diameter of 1.5mm and a stroke of 5mm. The probe tail is rigidly connected to the pull rod of the Milang KSM miniature pull rope displacement sensor. The displacement sensor has a range of 5mm, an accuracy of 0.01mm, and outputs a 0-3.3V analog signal. When the probe is pressed and retracts, it drives the displacement sensor pull rod to move synchronously, realizing the real-time acquisition of the probe retraction distance. The probe and displacement sensor are installed as a whole in an insulating base to avoid signal interference.

[0038] The pullback actuator includes a wire harness clamping assembly, a closed-loop controllable drive actuator unit, and a carrier signal transmitting unit. The drive actuator unit uses a Panasonic MSMF012L1U2M servo motor with a rated torque of 0.32 N·m, equipped with a 20-bit incremental encoder and a 10:1 planetary gear reducer. The servo motor driver is configured in a position + speed dual closed-loop mode, with an electronic gear ratio set to 10000 pulses / mm, achieving a stroke control accuracy of 0.01mm. The servo motor output shaft is rigidly connected to the drive roller of the wire harness clamping assembly via a coupling. A Dayang Sensor DYZ-101 tension sensor with a range of 0-50N, an accuracy of 0.1%FS, and an output of 0-3.3V analog signal is installed in series at the fixed end of the drive roller. The device is used to collect the tension value of the roller on the wire harness in real time. The wire harness clamping assembly includes an active roller and a driven roller. The roller body is 30mm in diameter and made of nitrile rubber. The surface is processed with diamond-shaped anti-slip texture with a depth of 0.5mm. The driven roller is equipped with a miniature clamping cylinder. When the cylinder extends, the driven roller presses down and cooperates with the active roller to clamp the wire harness to be tested. The carrier signal transmission unit adopts an FSK frequency shift keying modulation module based on the THM3070 chip. The working frequency band is 125kHz and the transmission power is 10dBm. It is equipped with a 20mm diameter coupling coil. The coupling coil is fixed at the wire harness passage position between the active roller and the driven roller. The distance between the coil and the wire harness is ≤2mm to ensure that the carrier signal can penetrate the wire harness insulation and form a stable capacitive coupling circuit with the wire core.

[0039] The human-machine interface unit adopts a 2.8-inch industrial serial touch screen with a resolution of 320×240. It supports the Modbus-RTU protocol and communicates with the main control processing unit through the USART1 interface. It is equipped with a parameter setting interface, a real-time data display interface, a historical data query interface, and a fault alarm interface. The human-machine interface unit is also equipped with red and green dual-color LED indicators and a 5V active buzzer, which are connected to the PE2 pin of the main control processing unit after being driven by ULN2003 to realize the audible and visual prompts of the test status.

[0040] Before this embodiment is put into formal use, system calibration needs to be completed. The specific steps are as follows: The first step is system zero-point calibration. After the system is powered on, enter the calibration mode through the human-machine interface unit, select the zero-point calibration function, and ensure that the conductive contact probe is not under pressure, the wire harness clamping component is not clamped, and the tension sensor is not under load. After clicking start calibration, the main control processing unit continuously collects the ADC sampling values ​​of the probe displacement sensor and the tension sensor 100 times, takes the average value as the zero-point reference value, and stores it in the calibration parameter area of ​​the external Flash. After calibration, the displacement value ≤0.01mm and the tension value ≤0.05N under no-load conditions are considered qualified.

[0041] The second step is probe displacement calibration. Enter the displacement calibration interface, use a standard thickness feeler gauge to press the probe head and retract it. Input standard displacement values ​​of 0.1mm, 0.5mm, 1.0mm, 3.0mm, and 5.0mm in sequence. The main control processing unit collects the ADC sampling values ​​under the corresponding displacement, fits and generates a displacement-ADC linear curve and stores it in Flash. After calibration, re-measure with a 0.3mm standard feeler gauge. The indication error ≤ ±0.02mm is considered qualified.

[0042] The third step is to calibrate the tension sensor. Enter the tension calibration interface, fix the 0.1 grade standard force gauge to the clamping end of the wire harness clamping assembly, clamp the force gauge rod with the driven roller, and slowly apply tension through the servo motor. Input the standard tension values ​​of 0N, 10N, 20N, 30N, and 50N in sequence. The main control processing unit collects the ADC sampling values ​​under the corresponding tension, fits and generates a tension-ADC linear curve and stores it in Flash. After calibration, repeat the application of a 10N standard tension three times. The indication error ≤ ±0.2N is considered qualified.

[0043] The fourth step is carrier signal sensitivity calibration. Enter the carrier calibration interface and set the standard 0.5mm... 2The wire harness is placed on the wire harness clamping assembly at the wire passage position and clamped. After clicking "Start Calibration", the carrier signal transmitting unit automatically adjusts the transmission power gradually from 1dBm to 10dBm. The main control processing unit detects the signal-to-noise ratio of the carrier signal in real time and locks the minimum transmission power with a signal-to-noise ratio ≥20dB as the default operating parameter and stores it in Flash. After calibration, the wire harness is plugged and unplugged 3 times. If the carrier signal can be stably detected without packet loss each time, it is considered qualified.

[0044] The complete testing process in this embodiment, with specific steps, is as follows: S1, System Initialization and Parameter Configuration: After the system is powered on, the main control processing unit executes a self-test program, sequentially verifying the sensor communication status, motor driver status, solenoid valve status, and carrier module status. If no abnormalities are found, the human-machine interface unit enters the main interface. If a self-test fails, a red indicator light illuminates and a buzzer sounds continuously, and the human-machine interface unit simultaneously displays the fault code. The operator selects the model of the wire harness under test on the main interface of the human-machine interface unit and retrieves the pre-stored parameter template with one click. The default parameters of the template include: tensile test threshold 10N, stroke protection upper limit 50mm, probe displacement qualified range 0.1mm-0.5mm, carrier interruption judgment threshold 500ms, motor tightening speed 0.5mm / s, and tensile sampling frequency 100Hz. If custom parameters are required, the corresponding values ​​can be entered into the parameter modification interface. After clicking save, the parameters are automatically stored in the external Flash and can be directly retrieved the next time the system is powered on.

[0045] S2, Sheath Locking and Harness Connection: The operator places the sheath of the harness to be tested into the positioning cavity of the detection module, presses the start button on the machine body, and the main control processing unit outputs a control signal to drive the sheath locking cylinder to extend and press the sheath. After the magnetic ring sensor feeds back the locking signal, the main control processing unit confirms that the locking is complete. If no locking signal is received within 3 seconds, the locking is judged to have failed, triggering the red indicator light to light up and the buzzer to sound continuously, prompting the operator to reposition the sheath. The operator inserts the crimped harness terminal into the corresponding hole of the sheath, so that the terminal is fully inserted and in full contact with the conductive contact probe. The probe retracts under pressure. Then, the non-connected end of the harness is placed between the active roller and the driven roller, and the clamping button is pressed. The main control processing unit controls the clamping cylinder of the driven roller to extend and clamp the harness. The clamping force is preset to 2N to avoid damaging the harness insulation.

[0046] S3, Single-ended lossless continuity pre-detection and contact reliability verification: After receiving the clamping signal from the wire harness clamping assembly, the main control processing unit immediately activates the carrier signal transmitting unit to transmit a 125kHz FSK modulated carrier signal. The coupling coil transmits the carrier signal through the wire harness insulation, forming a capacitive coupling circuit with the wire core. The continuity contact probe receives the carrier signal coupled to the wire core and transmits it to the main control processing unit. The main control processing unit continuously detects the carrier signal for 100ms. If a stable carrier signal with a signal-to-noise ratio ≥20dB is continuously received, the wire harness foundation is determined to be normally conductive. If no valid carrier signal is received, the connection is determined to be active. An error occurs, triggering a red indicator light and a continuous buzzer sound. The human-machine interface displays "Conduction failed, please check terminal connection," terminating the current test process. Simultaneously, the main control processing unit reads the retraction distance data of the conduction contact probe. If the data is within the acceptable range of 0.1mm-0.5mm, the terminal and probe are considered to be in reliable contact. If the retraction distance is less than 0.1mm, the terminal is considered not fully inserted. If the retraction distance is greater than 0.5mm, the probe is considered to be over-compressed. Both are considered as poor contact, triggering a red indicator light and a continuous buzzer sound, prompting the operator to adjust the wiring harness. After adjustment, the verification is re-executed.

[0047] S4, Integrated Pull-back Test and Real-time Monitoring: After the continuity pre-detection and contact reliability verification are passed, the main control processing unit sends an enable signal to the servo motor driver. After the motor starts, it first rotates rapidly at a speed of 2mm / s to straighten the wire harness. When the tensile force reaches 0.5N, it immediately switches to a uniform loading speed of 0.5mm / s to perform the pull-back test to avoid impacting the wire harness. During the test, the main control processing unit collects tensile sensor data at a frequency of 100Hz through a 10ms timer interrupt. At the same time, it checks the level status of the carrier signal pin every 10ms to monitor the continuity of the carrier signal in real time. When the tensile force reaches the preset 10N threshold, or the motor travel reaches the protection upper limit of 50mm, the main control processing unit immediately stops the motor loading and enters the result judgment stage.

[0048] S5, Test Result Judgment and Execution: If the main control processing unit continuously receives a valid carrier signal without continuous interruption throughout the entire process of loading the motor to the 10N tensile force threshold, then the continuity test and pull-back test of the wiring harness are deemed qualified. The main control processing unit controls the motor to reverse and reset, the driven roller clamping cylinder is released, triggering the green indicator light to illuminate and the buzzer to sound once. The human-machine interface unit displays "Test Qualified" and simultaneously stores the wiring harness number, test time, peak tensile force, and test results to the external Flash, which can store no less than 100,000 historical test data entries. If, during the test, the main control processing unit detects no valid carrier signal for 50 consecutive times (i.e., 500ms), then the terminal is deemed to have come loose and the test is deemed unqualified. Simultaneously, an emergency stop command is sent to the motor, the motor immediately stops loading and reverses and resets, the driven roller clamping cylinder is released, triggering the red indicator light to illuminate and the buzzer to sound three times. The human-machine interface unit displays "Terminal Pulled Out, Test Failed" and simultaneously records the fault data and locks the current workstation. The operator must press the reset button to start the next test.

[0049] In this embodiment, the core control logic of the main control processing unit is as follows: After the system is powered on, the clock, GPIO, ADC, timer, UART, and I2C peripherals are initialized. The calibration parameters and test templates stored in the external Flash are read. After the system self-test is performed, the main loop is entered. In the main loop, the touch commands of the human-machine interaction unit are continuously scanned, the parameter configuration is updated, the button signals on the machine body are scanned and the corresponding locking, clamping, starting, and resetting actions are executed, the fault flag is detected and the alarm logic is executed, and the real-time data display and test status are refreshed. The ADC acquisition and sliding filtering of the tension value and displacement value are completed through the timer 2 update interrupt triggered once every 10ms, and the level status of the carrier detection pin is read and stored. The buffer sets the "terminal disengagement" fault flag when 50 consecutive carrier states are low, and sets the "test complete" flag when the tension or stroke value reaches the threshold. When the "terminal disengagement" or "test complete" flag is in the position, the test judgment function is triggered. If the "terminal disengagement" flag is 1, the motor enable is immediately turned off and an emergency stop command is output, controlling the motor to reset, releasing the clamping cylinder, triggering an audible and visual alarm and recording fault data, locking the test process and waiting for reset. If the "test complete" flag is 1 and the "terminal disengagement" flag is 0, the motor is controlled to reset, the clamping cylinder is released, a pass prompt is triggered and test data is recorded, the flags are cleared and the system enters standby mode, waiting for the next test to start.

[0050] This embodiment addresses common anomaly scenarios in practical use and sets corresponding judgment and handling methods: For the anomaly of continuous alarm due to cylinder locking failure, the main control processing unit determines the fault by not receiving a locking signal from the magnetic ring sensor within 3 seconds. The handling steps are to check whether the sheath is fully inserted into the positioning cavity, check whether the cylinder solenoid valve wiring and air source pressure are within the 0.4-0.6MPa range, and check whether the magnetic ring sensor position is offset; For the anomaly of failure to start the test due to poor contact alarm, the fault is determined by the probe retraction distance exceeding the acceptable range. The handling steps are to check whether the terminal is fully inserted and whether it is misaligned, clean the gold plating layer on the probe head to remove the oxide layer, and recalibrate the probe displacement sensor; For the anomaly of no carrier signal due to failure of conduction pre-detection, the fault is determined by continuous 100ms... If no valid carrier signal is detected, the fault is identified. The troubleshooting steps are as follows: check if the wire harness is placed at the corresponding position of the carrier coupling coil with a spacing of ≤2mm, recalibrate the carrier transmission power, check if the probe wiring is loose or if there is grounding interference, and check if the terminals have poor crimping or broken wires. For the abnormality of the wire harness slipping and no change in tension during the pull-back process, the fault is identified by the indicated value fluctuating ≤0.2N when the tension is loaded to more than 5N. The troubleshooting steps are as follows: clean the oil stains on the roller surface, replace the worn rubber roller, adjust the roller clamping force, and reduce the motor tightening speed. For the abnormality of motor overload alarm emergency stop, the fault is identified by the overload signal fed back by the motor driver. The troubleshooting steps are as follows: check if the wire harness is stuck by foreign objects, check if the motor wiring is loose, and adjust the motor tightening speed to reduce the loading impact.

[0051] Example 3: This example is a multi-station cascaded parallel testing system adapted for mass production of automotive wiring harnesses. Based on Example 2, it expands the cascaded communication interface to achieve parallel synchronous testing of multiple wiring harnesses. The testing system includes a main control processing unit, a detection module, a human-machine interface unit, a cascaded communication interface, and 16 sets of pull-back actuators connected through the cascaded communication interface. The cascaded communication interface uses an RS485 industrial bus interface, equipped with a MAX485 transceiver chip, and connects to the USART3 interface of the main control processing unit. The bus adopts a daisy-chain topology, with 120Ω terminating resistors at both ends to suppress signal reflection. The bus cable uses shielded twisted-pair cable with a diameter of 0.75mm. 2 It has a maximum transmission distance of 100m and supports cascading access of up to 32 pullback actuators.

[0052] The station addresses of the 16 pullback actuators are set sequentially from 0x01 to 0x10. Each station is equipped with an independent STM32F103C8T6 slave microcontroller. The slave microcontroller controls the servo motor, roller clamping cylinder, and carrier signal transmitting unit of the corresponding station, and collects tension, displacement, and carrier signal data. It communicates with the main control processing unit via RS485 bus, using the standard Modbus-RTU protocol with a baud rate of 19200bps, 8 data bits, 1 stop bit, and no parity. Each station is equipped with an independent 24V / 3A switching power supply to avoid power voltage drop caused by simultaneous operation of multiple stations. The main control processing unit is powered by an independent linear power supply to avoid electromagnetic interference caused by motor operation.

[0053] In this embodiment, the main control processing unit adopts a polling scheduling mechanism with a cycle of 100ms. In each cycle, it communicates sequentially with the slave microcontrollers of 16 workstations, reads the status data of each workstation, and sends control commands. The communication time of a single workstation is ≤5ms to avoid bus data conflicts and ensure that there is no delay in the control and data acquisition of each workstation. The test process of each workstation is completely independent. The main control processing unit is only responsible for parameter distribution, status acquisition, and result summarization. The core test judgment logic is executed independently by the workstation slave microcontroller. The failure of a single workstation does not affect the normal operation of other workstations. The main control processing unit sets up a mutex lock logic, which only allows the locking and unlocking of the sheath of the detection module to be executed when all workstations are in standby mode, so as to avoid test misjudgment caused by sheath displacement during the test.

[0054] The complete operation process of this embodiment is as follows: The operator locks the sheath of the wire harness to be tested into the positioning cavity of the detection module, and inserts the terminals of the 16 wire harnesses into the corresponding holes of the sheath in sequence. For each wire harness inserted, the non-plug end of the wire harness is placed on the wire harness clamping component of the corresponding station, and the station clamping button is pressed to complete the wire harness pre-clamping. After all wire harnesses are plugged in, the operator presses the batch start button on the main control panel. The main control processing unit sends start commands to all stations in sequence. The slave microcontrollers of each station synchronously perform continuity pre-detection and contact reliability verification. Stations that pass the pre-detection automatically start the pull-back test. Stations that fail the pre-detection immediately output an alarm, without affecting the normal operation of other stations. During the test, the operator does not need to wait for the test to be completed and can prepare the next set of wire harnesses and sheaths simultaneously. After all stations in the current batch have been tested, the main control panel outputs an audible and visual prompt. The operator loosens the sheath, removes the tested wire harness, and replaces the next set of sheaths, realizing a zero-wait cyclic operation.

[0055] In this embodiment, the main control processing unit collects test data from all workstations in real time. After each wire harness is tested, it automatically summarizes and stores the workstation number, wire harness number, test time, peak tensile force, test result, and fault code in the external Flash. The main control processing unit connects to the production line MES system through the W5500 Ethernet module, uses the TCP / IP protocol, and uploads test data in real time according to the standard data format of the MES system to achieve quality traceability throughout the wire harness production process. The human-machine interaction unit can display the yield and fault type distribution data of each workstation in real time, which is convenient for production line management and optimization.

[0056] Example 4: Based on Example 2, hardware and parameter adaptation is performed to cover the testing needs of large-diameter high-voltage wire harnesses, ultra-fine wire harnesses, and shielded wire harnesses. For 6mm wire diameter... 2 -10mm 2 For automotive high-voltage wiring harnesses with a rated pull-back force of 50N-200N, the following adjustments are made: the wiring harness clamping assembly is replaced with a claw clamping structure, with V-shaped anti-slip grooves on the inner side of the claws, made of polyurethane material to avoid damaging the insulation of the high-voltage wiring harness; the drive execution unit is replaced with a 1.5kW servo motor, equipped with a tension sensor with a range of 0-200N; the coupling coil of the carrier signal transmitting unit is replaced with a large-size coil with a diameter of 50mm to adapt to large-diameter wiring harnesses; the test parameters are configured as follows: tension test threshold 80N-200N, motor tightening speed 0.2mm / s, carrier frequency adjusted to 63kHz, carrier interruption judgment threshold 300ms, roller clamping force adjusted to 5N-10N, and wiring harness straightening threshold adjusted to 2N.

[0057] For wire diameter 0.3mm 2 -0.5mm 2 For automotive ultra-fine signal harnesses with insulation thickness ≤ 0.2mm and rated pull-back force 2N-10N, the following adjustments are made: The rollers of the harness clamping assembly are replaced with silicone material of 30 Shore A hardness to avoid damage to the thin-walled insulation during clamping; the tension sensor is replaced with a high-precision sensor with a range of 0-10N and an accuracy of 0.05%FS; the coupling coil of the carrier signal transmitting unit is replaced with a miniature coil with a diameter of 10mm; the test parameters are configured as follows: tension test threshold 2N-5N, motor tightening speed 0.3mm / s, roller clamping force 0.5N-1N, carrier frequency adjusted to 134kHz, probe displacement qualified range adjusted to 0.05mm-0.3mm, motor straightening speed adjusted to 0.5mm / s, and straightening threshold adjusted to 0.2N.

[0058] For automotive shielded wiring harnesses with aluminum foil or braided shielding layers, the following adjustments are made: The carrier signal transmitting unit uses a differential coupling coil with a matching metal shielding shell to avoid signal attenuation caused by the shielding layer; an insulating bushing is added at the wire crossing point to ensure no direct contact between the shielding layer and the coupling coil, preventing signal short circuits; the test parameters are configured as follows: carrier transmission power is increased to 15dBm, carrier frequency is adjusted to 433MHz, and a carrier signal amplitude threshold judgment is added, only signals with amplitude ≥ preset thresholds are considered valid; in the test process, the continuity pre-detection stage adds shielding layer continuity detection, using an auxiliary probe to contact the shielding layer, detecting the carrier coupling signal of the shielding layer, and simultaneously verifying that the shielding layer is unbroken, achieving synchronous testing of the wiring harness core wire and the shielding layer.

[0059] 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. An integrated testing system for non-destructive continuity and precise pull-back of automotive wiring harnesses, characterized in that, It includes a main control processing unit, detection modules electrically connected to the main control processing unit, at least one set of pullback actuators, and a human-machine interaction unit; The detection module includes a sheath locking mechanism and a conductive contact probe with displacement detection function. The sheath locking mechanism is used to position and fix the sheath of the wire harness under test. The conductive contact probe is used to contact the wire harness terminal inserted into the sheath, receive the carrier signal transmitted by the wire harness, and collect the displacement data of the probe and transmit it to the main control processing unit. The pull-back actuator includes a wire harness clamping assembly, a closed-loop controllable drive execution unit, and a carrier signal transmitting unit. The wire harness clamping assembly is used to clamp and fix the non-plug-in ends of the wire harness under test. The drive execution unit is connected to the wire harness clamping assembly and is used to drive the wire harness clamping assembly to perform the tightening and pull-back actions of the wire harness, and to feed back the tension, torque, and stroke data to the main control processing unit in real time. The carrier signal transmitting unit is used to transmit a carrier signal that can penetrate the wire harness insulation to the wire harness under test through non-contact coupling, without the need for a hard connection with the wire harness core or the formation of a double-ended hard-connection electrical circuit. The main control processing unit is used to perform test logic judgment based on the received carrier signal, probe displacement data, tension, torque and stroke data, and output control commands to each module; The human-computer interaction unit is used for configuring test parameters, displaying test results, and providing device status prompts.

2. The integrated testing system for non-destructive continuity and precise pull-back of automotive wiring harnesses according to claim 1, characterized in that, The carrier signal transmitting unit adopts any one or more combinations of amplitude shift keying, frequency shift keying, and phase shift keying carrier modulation technology. The carrier signal operates in the frequency band of 10kHz-1MHz and can penetrate the wire harness insulation sheath with a thickness of 0.2mm-5mm to form a coupled signal loop with the wire harness core.

3. The integrated testing system for non-destructive continuity and precise pull-back of automotive wiring harnesses according to claim 1, characterized in that, The sheath locking mechanism can be any one of pneumatic locking, electric locking, or hydraulic locking, with a locking positioning accuracy of not less than ±0.5mm, and can be adapted to wire harness sheaths of different shapes and hole specifications.

4. The integrated testing system for non-destructive continuity and precise pull-back of automotive wiring harnesses according to claim 1, characterized in that, The drive actuator can be any one of a servo motor, stepper motor, linear motor, or pneumatic servo actuator. The tension control range is 2N-200N, the stroke control accuracy is not less than 0.5mm, and it supports user-defined settings for tension / torque test thresholds and stroke protection upper limits.

5. The integrated testing system for non-destructive continuity and precise pull-back of automotive wiring harnesses according to claim 1, characterized in that, The conductive contact probe integrates a contact or non-contact displacement sensing unit with a displacement detection accuracy of not less than 0.05mm. The main control processing unit has a preset probe displacement qualified range. Only when the probe displacement data is within the qualified range is it determined that the terminal and probe are in reliable contact, and the pull-back test process is started.

6. The integrated testing system for non-destructive continuity and precise pull-back of automotive wiring harnesses according to claim 1, characterized in that, The test logic judgment rule of the main control processing unit is as follows: During the pullback test, the continuity of the carrier signal and the pull / torque data of the drive execution unit are monitored in real time; if the interruption duration of the carrier signal reaches the preset interruption threshold, it is immediately determined that the terminal is disconnected and the test fails, and the drive execution unit is controlled to stop the operation and reset; if the output pull / torque of the drive execution unit reaches the preset test threshold and the carrier signal is continuous without interruption throughout the process, it is immediately determined that both the conduction and pullback tests are passed, and the drive execution unit is controlled to reset.

7. The integrated testing system for non-destructive continuity and precise pull-back of automotive wiring harnesses according to claim 1, characterized in that, It also includes a cascading communication interface, which is connected to the main control processing unit and adopts any one of the following communication methods: industrial bus, Ethernet, or wireless communication. It supports at least 32 groups of pullback actuators to be cascaded at the same time. The main control processing unit can perform independent addressing, independent control, and parallel synchronous testing on each group of pullback actuators.

8. The integrated testing system for non-destructive continuity and precise pull-back of automotive wiring harnesses according to claim 1, characterized in that, The wire harness clamping assembly adopts any one of the following types: roller clamping, claw clamping, and clamp clamping. The clamping contact surface is equipped with an anti-slip and friction-enhancing structure, which can accommodate wires with a diameter of 0.3mm. 2 -10mm 2 The automotive wiring harness is clamped and fixed.

9. The integrated testing system for non-destructive continuity and precise pull-back of automotive wiring harnesses according to claim 1, characterized in that, The main control processing unit has a built-in storage module that can store at least 1,000 sets of test parameter templates for wire harness specifications. It can also record and store all test process data and results data in real time, and supports integration with the production line MES system and ERP system to achieve full-process quality traceability of wire harness testing.

10. A method for integrated non-destructive continuity and precise pull-back testing of automotive wiring harnesses, using the testing system described in any one of claims 1-9, characterized in that, Includes the following steps: S1 parameter configuration: Configure the corresponding test parameters according to the specifications of the wire harness under test, including tensile test threshold, stroke protection upper limit, carrier signal parameters, and carrier interruption judgment threshold; S2 Sheath Fixing and Wire Harness Insertion: Position and lock the sheath of the wire harness to be tested, insert the wire harness terminal into the corresponding hole of the sheath, so that the terminal contacts the conductive contact probe, and at the same time clamp and fix the non-plug-in end of the wire harness. S3 Single-Ended Non-Destructive Continuity Pre-Detection: A carrier signal that can penetrate the insulation of the wire harness is emitted to the wire harness under test through non-contact coupling. There is no need to make a hard connection with the wire harness core or form a double-ended hard connection electrical circuit. The carrier signal is received by the continuity contact probe to determine the basic continuity status of the wire harness. At the same time, the contact reliability between the terminal and the probe is verified by the displacement data of the probe. S4 Integrated Pull-back Test and Real-time Monitoring: After the continuity pre-detection and contact verification are passed, the wire harness is tightened at a preset speed to perform a pull-back test. During the test, tension / torque data is collected in real time, and the continuity of the carrier signal is continuously monitored. S5 Test Result Judgment: If the carrier signal interruption duration reaches the preset interruption threshold, the terminal is deemed to have come off and the test has failed; if the pulling force reaches the preset test threshold and the carrier signal is continuous and uninterrupted throughout the entire process, both the conduction and pull-back tests are deemed to have passed.

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