Processing parameter monitoring method and system for wire harness terminal production

Abstract

The invention relates to the technical field of image data processing, in particular to a processing parameter monitoring method and system for wire harness terminal production, and the method comprises the steps: obtaining continuous multi-frame images in a wire harness terminal crimping process; calculating the initial sectional areas of the wire harness conductor and the crimping wing in the crimping area of any image; respectively performing temperature compensation and vibration compensation on the initial sectional areas of the wire harness conductor and the crimping wing to obtain the actual sectional areas of the wire harness conductor and the crimping wing, and calculating the compression ratio of the wire harness terminal in the crimping area based on the actual sectional areas of the wire harness conductor and the crimping wing; adjusting the crimping force according to the compression ratio by using a PID control model; and evaluating the crimping quality of the wire harness terminal based on the compression ratio. The sectional area is dynamically calibrated by introducing temperature compensation and vibration intensity, quality misjudgment caused by only depending on pressure data is avoided, the crimping force is adjusted in real time through the PID control model, pressure output is dynamically optimized according to the crimping state, and it is ensured that the crimping process is stable and accurate.

Description

Technical Field

[0001] This invention relates to the field of image data processing technology, and in particular to a method and system for monitoring processing parameters in wire harness terminal production. Background Technology

[0002] As the neural network for power and signal transmission in vehicles, automotive wiring harness systems are critical infrastructure ensuring the stable operation of vehicle electronic equipment. As the core component of electrical connections, the quality of the crimping between the wiring harness terminals and the metal wire harness conductors directly determines key performance indicators such as contact resistance and mechanical strength, playing a decisive role in the reliability and safety of the vehicle's electrical system.

[0003] Currently, with the accelerated trend of automotive intelligence and electrification, the number of in-vehicle electronic devices is surging, and the complexity of wiring harness systems is constantly increasing. The requirements for the stability and consistency of wiring harness terminal crimping processes are becoming increasingly stringent. Although automotive wiring harness terminal production is moving towards automation and standardization, crimping quality problems still frequently occur, becoming a bottleneck restricting the high-quality development of the industry.

[0004] Poor crimping of wiring harness terminals can lead to contact failures and abnormal signal transmission, causing not only malfunctions in onboard electronic equipment but also, in severe cases, threats to driving safety. Traditional quality monitoring methods have significant limitations: Firstly, destructive sampling using post-crimping profile analyzers or optimizing initial crimping parameters based on historical data cannot monitor the production process in real time online, making timely intervention for anomalies difficult and resulting in uncontrollable crimping quality. Secondly, monitoring technologies often rely on crimping force sensors to collect crimping force curves and judge quality by comparing them with preset standard waveforms. Using only crimping force data can easily lead to misjudgments of crimping quality, reducing production efficiency and seriously affecting the long-term reliability and safety of the vehicle's electrical system. Summary of the Invention

[0005] To address the aforementioned technical problems of uncontrollable and misjudged crimping quality detection during the crimping process, this invention provides solutions in the following aspects.

[0006] In a first aspect, the present invention provides a method for monitoring processing parameters in the production of wire harness terminals, the method comprising: The process involves acquiring multiple consecutive frames of images during the crimping process of wire harness terminals; acquiring the crimping area of ​​any image; calculating the initial cross-sectional area of ​​the wire harness conductor and crimping wing in the crimping area; calculating the actual cross-sectional area of ​​the wire harness conductor and crimping wing, including: performing temperature compensation on the initial cross-sectional area of ​​the wire harness conductor and crimping wing to obtain the temperature-compensated cross-sectional area of ​​the wire harness conductor and the crimping wing; correcting the temperature-compensated cross-sectional area of ​​the wire harness conductor based on the vibration intensity of the wire harness conductor to obtain the actual cross-sectional area of ​​the wire harness conductor; correcting the temperature-compensated cross-sectional area of ​​the crimping wing based on the vibration intensity of the crimping wing to obtain the actual cross-sectional area of ​​the crimping wing; calculating the compression ratio of the wire harness terminal in the crimping area based on the actual cross-sectional area of ​​the wire harness conductor and the crimping wing; adjusting the crimping force according to the compression ratio of the wire harness terminal using a PID control model; crimping the wire harness terminal using the crimping force to obtain a crimped wire harness terminal; and evaluating the crimping quality based on the compression ratio of the crimped wire harness terminal.

[0007] This invention calculates the actual cross-sectional area of ​​the wire harness terminal and crimping fin through temperature and vibration compensation, accurately reflecting the actual dimensions of the wire harness conductor and crimping fin under complex working conditions. This provides a reliable data foundation for subsequent analysis and avoids the misjudgment problems caused by relying solely on pressure data in existing technologies. Simultaneously, it calculates the compression ratio based on the actual cross-sectional area and adjusts the crimping force in real time using a PID control model, making the crimping process more stable and accurate, avoiding problems such as poor connection caused by improper crimping force. Evaluating crimping quality based on the compression ratio allows for the timely detection of potential quality issues during production, facilitating timely adjustments to process parameters, improving the quality and production efficiency of wire harness terminals, reducing the defect rate, and enhancing product reliability and stability.

[0008] Preferably, the step of correcting the cross-sectional area of ​​the temperature-compensated wire harness conductor based on the vibration intensity of the wire harness conductor to obtain the actual cross-sectional area of ​​the wire harness conductor includes: normalizing the vibration intensity of the wire harness conductor to obtain a normalized conductor vibration value; multiplying the normalized conductor vibration value by a preset conductor vibration influence factor and adding it to 1 to obtain a conductor vibration correction coefficient; and multiplying the conductor vibration correction coefficient by the cross-sectional area of ​​the temperature-compensated wire harness conductor to obtain the actual cross-sectional area of ​​the wire harness conductor.

[0009] This invention takes into account vibration influence factors and vibration intensity, enabling precise correction of the cross-sectional area to adapt to complex working conditions. The use of a normalization function eliminates interference from differences in data magnitude, ensuring calculation accuracy. This guarantees reliable wiring harness connections, avoids loosening caused by vibration, and improves electrical performance. Simultaneously, it provides precise data for wiring harness design and production, aiding in parameter optimization, improving product quality and stability, and reducing the risk of failure.

[0010] Preferably, the step of correcting the cross-sectional area of ​​the temperature-compensated press-fit wing based on the vibration intensity of the press-fit wing to obtain the actual cross-sectional area of ​​the press-fit wing includes: normalizing the vibration intensity of the press-fit wing to obtain a normalized press-fit wing vibration value; subtracting the product of the normalized press-fit wing vibration value and a preset press-fit wing vibration influence factor from 1 to obtain a press-fit wing vibration correction coefficient; and multiplying the press-fit wing vibration correction coefficient by the cross-sectional area of ​​the temperature-compensated press-fit wing to obtain the actual cross-sectional area of ​​the press-fit wing.

[0011] Preferably, obtaining the vibration intensity of the wire harness conductor includes: obtaining the wire harness conductor region in the crimping region; performing a Fourier transform on the wire harness conductor region to obtain a frequency domain signal; using wavelet transform to separate the high-frequency components of the frequency domain signal; and the vibration intensity of the wire harness conductor is the dominant frequency amplitude of the high-frequency components.

[0012] This invention converts the time-domain signal of the wire harness conductor into the frequency domain using Fourier transform, clearly presenting the frequency components, and accurately separates the high-frequency components using wavelet transform. Using the high-frequency signal as the vibration intensity provides strong targeting and high accuracy, offering a reliable basis for correcting the cross-sectional area of ​​the wire harness conductor, ensuring connection stability under complex vibrations, and improving electrical performance reliability.

[0013] Preferably, obtaining the vibration intensity of the press-fit wing includes: obtaining the press-fit wing region in the press-fit area; performing a Fourier transform on the press-fit wing region to obtain a frequency domain signal; using wavelet transform to separate the low-frequency component of the frequency domain signal; and the vibration intensity of the press-fit wing is the dominant frequency amplitude of the low-frequency component.

[0014] Preferably, the calculation of the PID control model includes an error signal, which is calculated by the compression ratio error of the wire harness terminals in the crimping area. The compression ratio error is the difference between the target compression ratio of the wire harness terminals in the crimping area and the compression ratio of the wire harness terminals in the crimping area.

[0015] Preferably, the PID control model includes PID parameter tuning, which includes: calculating the twist degree of the wire harness terminals in the crimped area of ​​the consecutive multi-frame images; when the twist degree of the wire harness terminals in the consecutive multi-frame images is greater than a preset twist degree threshold, the Ziegler-Nichols method is used to tune the PID parameters.

[0016] This invention accurately identifies abnormal crimping conditions by calculating the twist degree of wire harness terminals and comparing it with a threshold, avoiding the problem of lag in adjustment when traditional fixed parameters are adjusted when twisting deformation is severe. It employs the Ziegler-Nichols method to dynamically tune PID parameters, enabling rapid adaptation to complex crimping conditions, real-time optimization of crimping force output, effectively reducing crimping defects caused by twisting, and improving the shape consistency and connection stability of wire harness terminals.

[0017] Preferably, the twist degree of the wire harness terminal in the crimping region is the absolute value of the difference between the compression ratio of the wire harness terminal in the left region of the crimping region's axis of symmetry and the compression ratio of the wire harness terminal in the right region of the crimping region's axis of symmetry.

[0018] This invention determines the degree of twist by calculating the absolute value of the difference in compression ratios on both sides of the crimping axis, thus accurately quantifying the twisting of the wire harness terminal during the crimping process. The compression ratios on both sides directly reflect the degree of crimping in the corresponding areas, and the magnitude of the difference clearly shows the twisting state of the wire harness terminal.

[0019] Preferably, the step of temperature compensation for the initial cross-sectional areas of the wire harness conductor and the crimping wing to obtain the temperature-compensated cross-sectional areas of the wire harness conductor and the crimping wing includes: calculating the difference between the operating temperature of the crimping equipment and the preset standard temperature to obtain the temperature difference; multiplying the surface expansion coefficient of the wire harness conductor by the temperature difference and adding it to 1 to obtain the conductor compensation coefficient; recording the ratio of the initial cross-sectional area of ​​the wire harness conductor to the conductor compensation coefficient as the temperature-compensated cross-sectional area of ​​the wire harness conductor; multiplying the surface expansion coefficient of the crimping wing by the temperature difference and adding it to 1 to obtain the crimping wing compensation coefficient; and recording the ratio of the initial cross-sectional area of ​​the crimping wing to the crimping wing compensation coefficient as the temperature-compensated cross-sectional area of ​​the crimping wing.

[0020] This invention provides separate compensation for the wire harness conductor and the crimping flange, accurately reflecting the changes in size and cross-sectional area caused by temperature, thus avoiding the errors of integrated compensation. Utilizing the coefficient of surface expansion provides a direct representation of the effect of temperature on the cross-sectional area, effectively reducing the error caused by temperature in cross-sectional area calculations.

[0021] In a second aspect, the present invention provides a processing parameter monitoring system for wire harness terminal production, the processing parameter monitoring system comprising a memory and a processor, the memory storing computer program instructions, which, when executed by the processor, implement the processing parameter monitoring method for wire harness terminal production according to the first aspect of the present invention.

[0022] By adopting the above technical solution, a computer program for monitoring processing parameters in wire harness terminal production according to the first aspect of the present invention is generated and stored in a memory so that it can be loaded and executed by a processor, thereby making a terminal device based on the memory and the processor for convenient use.

[0023] The beneficial effects of this invention are as follows: This invention addresses the material properties of the wire harness conductor and the crimping wing by introducing temperature compensation and vibration intensity to dynamically calibrate the cross-sectional area. This accurately reflects the actual dimensional changes under complex working conditions such as high temperature and vibration environments, avoiding quality misjudgments caused by relying solely on pressure data in traditional methods. It provides a more reliable data foundation for crimping quality analysis. Simultaneously, the compression ratio is calculated based on the compensated actual cross-sectional area, and the crimping force is adjusted in real time through a PID control model. This closed-loop control system can dynamically optimize the pressure output according to the crimping state, ensuring a stable and accurate crimping process. It effectively solves problems such as poor contact and mechanical damage caused by improper crimping force, improving the electrical connection stability and mechanical reliability of the wire harness terminals. Attached Figure Description

[0024] Figure 1 A flowchart of a method for monitoring processing parameters in wire harness terminal production provided by an embodiment of the present invention; Figure 2 This is a structural block diagram of a processing parameter monitoring system for wire harness terminal production provided in an embodiment of the present invention. Detailed Implementation

[0025] The first aspect of this invention provides a method for monitoring processing parameters in the production of wire harness terminals, such as... Figure 1 As shown, the method includes steps S100-S700: Step S100: Acquire multiple consecutive frames of images during the wire harness terminal crimping process.

[0026] To elaborate, for ease of subsequent analysis and feedback adjustment mechanisms, it is necessary to use an industrial camera to capture multiple consecutive frames of images of the pressing process.

[0027] For example, assuming the production line frame rate is 20 FPS during the crimping process, the image acquisition frequency is one frame every 0.05 seconds, which means that an image will be acquired every 50 milliseconds.

[0028] In addition, the image needs to be converted to grayscale for easier subsequent processing.

[0029] Step S200: Obtain the crimped area of ​​any of the images.

[0030] To elaborate, the images captured by the camera will include some background images. Therefore, it is necessary to extract the contact area between the wire harness terminal and the wire, i.e., the crimped area, from the image. This crimped area can be obtained through edge detection algorithms or based on neural network models. Here, the method of obtaining the crimped area based on neural network models will be explained.

[0031] Specifically, firstly, for the image during the crimping process, the lens distortion parameters of the imaging device, including radial and tangential distortion coefficients, are calculated using a checkerboard calibration plate method, and then reverse-mapped to correct lens distortion. Secondly, the crimping region of the image is located using a neural network model, such as the YOLOv5 model, to obtain the bounding box of the crimping region. Finally, the crimping region is cropped based on the bounding box. The checkerboard calibration plate method is existing technology and will not be elaborated upon here.

[0032] Step S300: Calculate the initial cross-sectional area of ​​the wire harness conductor and the crimping wing in the crimping area.

[0033] To elaborate, the initial cross-sectional area calculation methods for the wire harness conductor and the crimping wing in the crimping area are the same. First, the total number of pixels in the corresponding area is obtained. Then, combined with camera calibration parameters such as the physical size corresponding to each pixel, the total number of pixels is converted into a physical area, thereby obtaining the initial cross-sectional area of ​​the corresponding area.

[0034] It should be noted that since the initial cross-sectional area here is calculated based on multiple frames of images during the crimping process, this initial cross-sectional area is not the cross-sectional area before crimping, but rather the cross-sectional area during the crimping process.

[0035] Step S400: Calculate the actual cross-sectional area of ​​the wire harness conductor and the crimping wing.

[0036] To elaborate, this invention takes into account, on the one hand, that increased temperature exacerbates the thermal expansion effect of materials. On the other hand, it considers that the wire harness conductor is composed of multiple stranded metal wires, making the material soft and sensitive to vibration, easily causing displacement or plastic deformation due to vibration. The crimping wing is usually made of a rigid copper alloy, and low-frequency vibrations such as mechanical impacts or periodic forces from equipment may induce plastic deformation.

[0037] Based on the above two considerations, the present invention performs temperature compensation and vibration compensation on the calculated initial cross-sectional area.

[0038] For temperature compensation, existing technologies often use the coefficient of linear expansion, while this invention directly uses the coefficient of surface expansion, and compensates for the wire harness conductor and the crimping wing separately.

[0039] The cross-sectional area of ​​the wire harness conductor after temperature compensation: ; Cross-sectional area of ​​the press-fit wing after temperature compensation: ; in, The cross-sectional area of ​​the wire harness conductor after temperature compensation. It is the initial cross-sectional area of ​​the wire harness conductor. It is the coefficient of surface expansion of the wire harness conductor. This refers to the operating temperature of the crimping equipment, which can be obtained through a temperature sensor. It is the preset standard temperature, usually set to... , It is the cross-sectional area of ​​the press-fit wing after temperature compensation. It is the initial cross-sectional area of ​​the press-fit wing. It is the surface expansion coefficient of the press-fit wing.

[0040] The wire harness conductor and the crimping flange may be made of different materials and therefore have different coefficients of thermal expansion. Compensating them separately more accurately reflects the individual changes in size and cross-sectional area caused by temperature variations, avoiding the errors that arise from treating them as a single entity. Using a surface expansion coefficient approximately twice that of linear expansion more directly reflects the impact of temperature changes on the cross-sectional area. This calculation method minimizes the influence of temperature on the calculation of the cross-sectional area.

[0041] It should be noted that the temperature compensation formula takes into account that most metallic materials, such as copper, aluminum, and steel, have isotropic properties, meaning their thermal expansion is uniformly distributed in three-dimensional space. In this case, the surface expansion coefficient can be approximated as twice the linear expansion coefficient. The linear expansion coefficient can be obtained based on the material properties; for example, for common conductors, the thermal expansion coefficient of copper conductors is approximately... The coefficient of thermal expansion of aluminum conductors is approximately... .

[0042] For vibration compensation, the cross-sectional areas of the wire harness conductor and the crimping wing are also compensated separately after temperature compensation.

[0043] The formula for calculating the cross-sectional area of ​​the conductor in the vibration-compensated wire harness is as follows: ; in, It is the actual cross-sectional area of ​​the wire harness conductor. It is the cross-sectional area of ​​the wire harness conductor after temperature compensation. This is the preset vibration influence factor for the wire harness conductor, with an empirical value of 0.15. It is the vibration intensity of the wire harness conductor. It is the standard normalization function.

[0044] This formula, by considering vibration influence factors and vibration intensity, can accurately compensate for the cross-sectional area of ​​the wire harness conductor based on actual vibration conditions. In vibration environments such as vehicle operation, the wire harness conductor will undergo microscopic deformation due to vibration. This calculation allows the cross-sectional area to better reflect the actual working conditions, avoiding problems such as loosening of the connection between the wire harness conductor and the crimping wing, and poor contact caused by long-term vibration, thus ensuring stable electrical connections.

[0045] Regarding the determination of the vibration intensity of the wire harness conductor in the formula, it is considered that the wire harness conductor is prone to fretting wear or loosening of contact due to high-frequency vibration. Generally speaking, the main sources of high-frequency vibration include motor electromagnetic noise and high-frequency current harmonics, which will manifest as high-frequency noise peaks in the FFT spectrum.

[0046] Therefore, the frequency domain signal can be obtained by processing the conductor region of the wire harness using Fourier transform, and then the high-frequency components of the frequency domain signal can be separated using wavelet transform. The energy magnitude of the high-frequency components can be accurately captured by the dominant frequency amplitude, thereby quantifying the impact of vibration on the internal friction, increased porosity, and reduced effective conductive cross-sectional area of ​​the wire harness conductor. Therefore, the dominant frequency amplitude can be used as the vibration intensity of the wire harness conductor. The greater the vibration intensity, the smaller the effective conductive cross-sectional area of ​​the wire harness conductor. In order to compensate for the cross-sectional gap expansion effect caused by vibration, the measured cross-sectional area needs to be increased accordingly.

[0047] The formula for calculating the cross-sectional area of ​​the vibratory-compensated press-fit wing is as follows: ; in, This is the actual cross-sectional area of ​​the press-fit wing. It is the cross-sectional area of ​​the press-fit wing after temperature compensation. This is the preset vibration influence factor for the press-fit wing, with an empirical value of 0.07. It is the vibration intensity of the press-fit wing. It is the standard normalization function.

[0048] Regarding the acquisition of the vibration intensity of the press-fit wing in the formula, considering that the press-fit wing is made of a relatively rigid copper alloy, low-frequency vibrations such as mechanical impacts or periodic forces from the equipment may induce macroscopic displacement or plastic deformation. The energy of low-frequency vibrations is mainly concentrated in the low-frequency region of the FFT spectrum. Therefore, the frequency domain signal of the press-fit wing region is obtained by processing it with Fourier transform, and then the low-frequency components of the frequency domain signal are separated using wavelet transform. The amplitude of the dominant frequency can reflect the influence of vibration on the geometric changes of the press-fit wing, such as the increase in the unfolded area of ​​the U-shaped or V-shaped region and the displacement of the contact surface. Therefore, the amplitude of the dominant frequency can be used as the vibration intensity of the press-fit wing. The greater the vibration intensity, the more likely it is to undergo plastic deformation or microscopic displacement, resulting in an increase in the geometric cross-sectional area. In this case, the measured cross-sectional area needs to be reduced accordingly to offset the increase in cross-sectional area caused by vibration.

[0049] It should be noted that the actual cross-sectional area of ​​the wire harness conductor and the crimping wing is the cross-sectional area of ​​the wire harness conductor and the crimping wing after vibration compensation.

[0050] This invention employs differentiated cross-sectional area correction based on the vibration intensity of the wire harness conductor and the crimping fins. This differentiated approach aims to improve the accuracy of cross-sectional area measurements in the presence of vibration interference, thereby providing more reliable data for subsequent compression ratio calculations and crimping quality assessments.

[0051] Step S500: Calculate the compression ratio of the wire harness terminal in the crimping region based on the actual cross-sectional area of ​​the wire harness conductor and the crimping wing.

[0052] To elaborate, the compression ratio of the wire harness terminals is used to evaluate the degree of crimping. The calculation formula is usually the ratio of the cross-sectional area of ​​the wire harness conductor after crimping to the cross-sectional area of ​​the wire harness conductor before crimping. This invention improves this calculation formula, specifically as follows: ; in, It is the first The compression ratio of the wire harness terminals in the crimped area of ​​the frame image. It is the actual cross-sectional area of ​​the wire harness conductor. This is the actual cross-sectional area of ​​the press-fit wing. It is the cross-sectional area of ​​the conductor in the wire harness before crimping. It is the cross-sectional area of ​​the front of the press-fit wing.

[0053] As can be seen from the above steps, the actual cross-sectional area of ​​the wire harness conductor and the actual cross-sectional area of ​​the crimping wing in this formula are both the initial cross-sectional areas after crimping, compensated for temperature and vibration. Temperature and vibration compensation make the calculated cross-sectional areas more closely resemble reality, thus making the calculated compression ratio more accurate.

[0054] It should be noted that obtaining the cross-sectional area of ​​the crimping wing and the wire harness conductor before crimping is existing technology, and will not be elaborated on here.

[0055] Step S600: Using a PID control model, adjust the crimping force according to the compression ratio of the wire harness terminals.

[0056] In detail, the PID control model is a feedback control mechanism used in industrial control systems. It dynamically adjusts the output by calculating the proportional, integral, and derivative terms of the error in real time to minimize the deviation between the target parameter and the setpoint. In this invention, the output value is the compression force, and the target parameter is the compression ratio.

[0057] During the crimping process of wire harness terminals, disturbances such as material plastic deformation, mold friction, and vibration exhibit nonlinear characteristics. PID control models can effectively adapt to these dynamic changes through multi-parameter coordination. For example, when vibration causes a sudden drop in the compression ratio, the derivative term responds quickly by monitoring the rate of change of the compression ratio error, increasing the crimping force in advance to suppress deviations and thus attenuate high-frequency disturbances. The integral term eliminates small steady-state deviations by accumulating historical compression ratio errors, ensuring long-term consistency, which is particularly important for scenarios where the compression ratio of automotive wire harness terminals needs to be controlled within a small range. The nonlinearity and time-varying nature of the crimping process (such as material plastic deformation, temperature changes, and equipment wear) can complicate the crimping force-compression ratio relationship. In this case, the proportional term can provide immediate correction capabilities for instantaneous errors caused by the elastic deformation of the wire harness terminal material or mechanical hysteresis of the equipment.

[0058] The calculation of the PID controller output value usually includes an error signal, which is the difference between the set value and the actual output value. In this invention, the error signal is calculated through the compression ratio error of the wire harness terminals in the crimping area. The compression ratio error of the wire harness terminals in the crimping area satisfies the following relationship: ; in, It is the first Compression ratio error of the wire harness terminals in the crimped area of ​​the frame image. It is the first The target compression ratio of the wire harness terminals in the crimped area of ​​the frame image. It is the first Compression ratio of the wire harness terminals in the crimped area of ​​the frame image.

[0059] This formula calculates the real-time compression ratio error of the wire harness terminals using multiple frames of images, and adjusts the crimping force during the crimping process based on this real-time error. During crimping, the motor adjusts the crimping force to regulate the degree of plastic deformation of the material, thereby changing the cross-sectional area of ​​the wire harness conductor and the cross-sectional area of ​​the crimping flange after crimping. For example, when the measured compression ratio is lower than the target compression ratio, the pressure should be increased to enhance the amount of plastic deformation. This formula, by adjusting the pressure value, ensures that the smaller the real-time compression ratio error, the closer the real-time dynamic compression ratio is to the target compression ratio.

[0060] This invention introduces a dimensionless conversion coefficient to transform the calculation formula in the PID control model, i.e., the output value of the PID controller. The transformation formula is as follows: ; in, It is the pressure applied to the PID controller output value after the dimension conversion coefficient is converted. It is the output value of the PID controller, that is, the pressure applied after the initial adjustment of the PID controller. It is the dimension conversion coefficient.

[0061] The dimensionless PID controller output value is used to convert the output value into the physical input range of the actuator, i.e., within the range of the pressure controller, while avoiding excessively large or small outputs due to integral saturation or derivative noise. By appropriately selecting the value of this proportional coefficient, signal conditioning is achieved, making the PID control operable and practically effective.

[0062] The formula for calculating the dimension conversion factor is: ; in, The dimension conversion coefficient is... Indicates the range of the pressure sensor. This indicates the range of the PID controller's output values. Take the minimum value, for example The purpose is to avoid the denominator being 0.

[0063] Regarding the range of PID output values, if it is an 8-bit controller, then the range of PID output is... That is, the range of PID output values .

[0064] This formula takes into account that, when designing a pressure control system, it is necessary to ensure that the pressure sensor's range can cover the system's required pressure range, and that the PID controller's output range can drive the actuator to operate within the required pressure range. The PID controller's output is adjusted based on feedback from the pressure sensor to make the actual pressure applied close to the set target pressure.

[0065] Furthermore, in order for the PID controller to effectively control the system, it is necessary to rationally select and adjust the proportional gain, integral gain, and derivative gain; this process is called PID parameter tuning. This invention adjusts the proportional gain by adjusting the twist degree of the wire harness terminals in the crimping area.

[0066] Specifically, the formula for calculating the twist of the wire harness terminals in the crimped area is as follows: ; in, It refers to the twist of the wire harness terminals in the crimped area. It is the compression ratio of the wire harness terminals in the region to the left of the crimping area's axis of symmetry. It is the compression ratio of the wire harness terminals in the region to the right of the crimping area's axis of symmetry. It is an absolute value.

[0067] It should be noted that the compression ratio of the wire harness terminals on the left or right side of the crimping area axis is not calculated by dividing the overall area compression ratio by 2, as this would result in a twist of 0. Therefore, the compression ratio of the wire harness terminals on the left and right sides is obtained by first calculating the actual cross-sectional area of ​​the wire harness terminals and crimping wings on the left and right sides respectively, and then calculating the compression ratio separately.

[0068] When the torsion is low, it indicates that there is no obvious asymmetric deformation in the pressing area; when the torsion increases, it indicates that asymmetric deformation begins to occur in the pressing area. For example, the operation of the pressing equipment causes a small displacement of the mold, resulting in uneven force on the left and right sides of the pressing area, or temperature changes cause differences in the thermal expansion of the material, thereby exacerbating the asymmetric deformation.

[0069] The symmetry and straightness of the crimped wire harness terminals directly affect the reliability of the connection. Generally, it is desirable for the crimped area of ​​the wire harness terminals to be as symmetrical as possible. Therefore, the twist of the wire harness terminals can be calculated using this symmetry property, and the PID parameters can be adjusted using the twist to dynamically compensate for non-uniformity and external disturbances such as vibration or temperature changes during the crimping process.

[0070] Regarding how to adjust PID parameters based on distortion, the process includes: calculating the distortion of the wire harness terminals in the crimped area of ​​multiple consecutive frames of images using the distortion formula mentioned above; setting a distortion threshold, empirically 2.5%, which can be adjusted according to requirements; and updating the PID controller parameters using the Ziegler-Nichols method when the distortion of the wire harness terminals in multiple consecutive frames exceeds the preset distortion threshold. In practice, the distortion of at least three consecutive frames can be calculated. The Ziegler-Nichols method is a classic empirical method for tuning PID controller parameters and is existing technology, so it will not be elaborated upon here.

[0071] If the distortion is less than the preset distortion threshold, the parameters are adjusted by trial and error, that is, by gradually adjusting the parameters and observing the system response to find the appropriate parameters.

[0072] Finally, a strategy needs to be set to stop PID tuning and begin quality inspection. Typically, a maximum limit is set for the number of PID tuning cycles. Inspection begins when the actual number of cycles reaches the limit or the compression ratio error converges to an acceptable range. There is no absolute universal value for the maximum number of tuning cycles; it highly depends on the specific pressing process, the control system's response speed, and the requirements for production efficiency and quality.

[0073] For example, the initial maximum number of adjustments is set to 10, and during actual production, it is continuously adjusted according to the system status. The compression ratio error range is set as follows: That is, when the compression ratio error is within If the value is within the specified range, it is considered acceptable.

[0074] Step S700: Crimp the wire harness terminal with the aforementioned crimping force to obtain a crimped wire harness terminal, and evaluate its crimping quality based on the compression ratio of the crimped wire harness terminal.

[0075] Calculate the compression ratio of the wire harness terminal in the crimping area in the image of the crimped wire harness terminal. If the compression ratio of the wire harness terminal is within the compression ratio error range then it is determined that the crimping of this wire harness terminal is qualified; if the compression ratio exceeds the dynamic tolerance band range, it is determined that the crimping of the wire harness terminal is unqualified.

[0076] In the second aspect of this embodiment, a processing parameter monitoring system for wire harness terminal production is provided. As Figure 2 shown, the processing parameter monitoring method system includes a memory and a processor. The memory stores computer program instructions, and when the computer program instructions are executed by the processor, it implements the processing parameter monitoring method of the first aspect of the present invention for wire harness terminal production.

[0077] The processing parameter monitoring method system further includes a communication bus, a communication interface, and other components well-known to those skilled in the art. Their settings and functions are known in the art, so they will not be elaborated here.

[0078] In the present invention, the aforementioned memory can be any tangible medium that contains or stores a program, and this program can be used by or combined with an instruction execution system, device, or component. For example, the computer-readable storage medium can be any suitable magnetic storage medium or magneto-optical storage medium, such as, resistive random access memory, dynamic random access memory, static random access memory, enhanced dynamic random access memory, high-bandwidth memory, hybrid memory cube, etc., or any other medium that can be used to store the required information and can be accessed by an application program, module, or both. Any such computer storage medium can be a part of the device or accessible or connectable to the device.

[0079] The above are all preferred embodiments of the present invention. The protection scope of the present invention is not limited hereby. Therefore, all equivalent changes made according to the structure, shape, and principle of the present invention shall be covered within the protection scope of the present invention.

Claims

1. A method for monitoring processing parameters in wire harness terminal production, characterized in that, include: Acquire multiple consecutive frames of images during the wire harness terminal crimping process; Obtain the overprinted area of ​​any of the images; Calculate the initial cross-sectional area of ​​the wire harness conductor and the crimping wing in the crimping region; Calculating the actual cross-sectional areas of the wire harness conductor and the crimping wing includes: performing temperature compensation on the initial cross-sectional areas of the wire harness conductor and the crimping wing to obtain the temperature-compensated cross-sectional areas of the wire harness conductor and the crimping wing; correcting the temperature-compensated cross-sectional area of ​​the wire harness conductor based on the vibration intensity of the wire harness conductor to obtain the actual cross-sectional area of ​​the wire harness conductor; and correcting the temperature-compensated cross-sectional area of ​​the crimping wing based on the vibration intensity of the crimping wing to obtain the actual cross-sectional area of ​​the crimping wing. Based on the actual cross-sectional areas of the wire harness conductor and the crimping wing, calculate the compression ratio of the wire harness terminals in the crimping region; Using a PID control model, the crimping force is adjusted according to the compression ratio of the wire harness terminals; The wire harness terminal is crimped using the crimping force to obtain a crimped wire harness terminal, and its crimping quality is evaluated based on the compression ratio of the crimped wire harness terminal.

2. The method for monitoring processing parameters in wire harness terminal production according to claim 1, characterized in that, The step of correcting the cross-sectional area of ​​the temperature-compensated wire harness conductor based on the vibration intensity of the wire harness conductor to obtain the actual cross-sectional area of ​​the wire harness conductor includes: The vibration intensity of the wire harness conductor is normalized to obtain the normalized conductor vibration value; The normalized conductor vibration value is multiplied by the preset conductor vibration influence factor and added to 1 to obtain the conductor vibration correction coefficient; The actual cross-sectional area of ​​the wire harness conductor is obtained by multiplying the conductor vibration correction factor by the temperature-compensated cross-sectional area of ​​the wire harness conductor.

3. The method for monitoring processing parameters in wire harness terminal production according to claim 1, characterized in that, The method of correcting the cross-sectional area of ​​the temperature-compensated press-fit wing based on the vibration intensity of the press-fit wing to obtain the actual cross-sectional area of ​​the press-fit wing includes: The vibration intensity of the press-fit wing is normalized to obtain the normalized press-fit wing vibration value; Subtract the product of the normalized press-fit wing vibration value and the preset press-fit wing vibration influence factor from 1 to obtain the press-fit wing vibration correction coefficient. The actual cross-sectional area of ​​the press-fit wing is obtained by multiplying the vibration correction coefficient of the press-fit wing by the cross-sectional area of ​​the press-fit wing after temperature compensation.

4. The method for monitoring processing parameters in wire harness terminal production according to claim 1, characterized in that, Obtaining the vibration intensity of the wire harness conductor includes: Obtain the wire harness conductor region within the crimped area; A frequency domain signal is obtained by performing a Fourier transform on the conductor region of the wire harness; Wavelet transform is used to separate the high-frequency components of the frequency domain signal; The vibration intensity of the wire harness conductor is the dominant frequency amplitude of the high-frequency component.

5. The method for monitoring processing parameters in wire harness terminal production according to claim 1, characterized in that, Obtaining the vibration intensity of the press-fit wing includes: Obtain the crimping wing area within the crimping area; The frequency domain signal is obtained by performing a Fourier transform on the press-fit wing region; The low-frequency components of the frequency domain signal are separated using wavelet transform; The vibration intensity of the press-fit wing is the dominant frequency amplitude of the low-frequency component.

6. The method for monitoring processing parameters in wire harness terminal production according to claim 1, characterized in that, The calculation of the PID control model includes an error signal, which is calculated by the compression ratio error of the wire harness terminals in the crimping area. The compression ratio error is the difference between the target compression ratio of the wire harness terminals in the crimping area and the compression ratio of the wire harness terminals in the crimping area.

7. The method for monitoring processing parameters in wire harness terminal production according to claim 1, characterized in that, The PID control model includes PID parameter tuning, which includes: Calculate the twist of the wire harness terminals in the crimped area of ​​the consecutive multi-frame images; When the twist of the wire harness terminals in the consecutive multi-frame images exceeds a preset twist threshold, the Ziegler-Nichols method is used to tune the PID parameters.

8. The method for monitoring processing parameters in wire harness terminal production according to claim 7, characterized in that, The twist of the wire harness terminals in the crimping region is the absolute value of the difference between the compression ratio of the wire harness terminals on the left side of the crimping region's axis of symmetry and the compression ratio of the wire harness terminals on the right side of the crimping region's axis of symmetry.

9. The method for monitoring processing parameters in wire harness terminal production according to claim 1, characterized in that, The step of performing temperature compensation on the initial cross-sectional areas of the wire harness conductor and the crimping wing to obtain the temperature-compensated cross-sectional areas of the wire harness conductor and the crimping wing includes: Calculate the difference between the operating temperature of the crimping equipment and the preset standard temperature to obtain the temperature difference; Multiply the surface expansion coefficient of the wire harness conductor by the temperature difference and add it to 1 to obtain the conductor compensation coefficient; the ratio of the initial cross-sectional area of ​​the wire harness conductor to the conductor compensation coefficient is recorded as the cross-sectional area of ​​the wire harness conductor after temperature compensation. Multiply the surface expansion coefficient of the press-fit wing by the temperature difference and add it to 1 to obtain the press-fit wing compensation coefficient; the ratio of the initial cross-sectional area of ​​the press-fit wing to the press-fit wing compensation coefficient is recorded as the cross-sectional area of ​​the press-fit wing after temperature compensation.

10. A processing parameter monitoring system for wire harness terminal production, characterized in that, The processing parameter monitoring system includes a processor and a memory. The memory stores computer program instructions, which, when executed by the processor, implement a processing parameter monitoring method for wire harness terminal production according to any one of claims 1-9.

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