Compression tester measured and controlled by computer for packaging product production

Abstract

The invention discloses a computer measurement and control compression tester for packaging product production, and relates to the technical field of computer measurement and control compression testers, the computer measurement and control compression tester comprises hardware equipment and a software system, the software system comprises a data acquisition module, a strength detection module, a feedback control module and a closed-loop adjustment module; the strength detection module is used for analyzing and calculating the collected data so as to obtain various mechanical property parameters of the packaging product; the feedback control module is used for adjusting the driving power of the hydraulic cylinder according to the deviation between an actual value measured by the pressure sensor and a preset target value; hardware equipment and a software system are combined, the data acquisition module adaptively adjusts the sampling frequency, the strength detection module comprehensively analyzes data and obtains multiple mechanical property parameters, the feedback control module regulates and controls the driving power of the hydraulic cylinder based on deviation, the closed-loop regulation module compensates errors in real time, the test precision and repeatability are improved, and the test efficiency is improved. And the intelligent level and the test reliability of the tester are integrally improved.

Description

Technical Field

[0001] The invention relates to the technical field of computer-controlled compression testing instruments, and in particular to a computer-controlled compression testing instrument for producing packaging products. Background Art

[0002] In the field of production and quality inspection of packaging products, the computer-controlled compression tester is a key device for evaluating the compression performance of packaging products. With the help of a computer control system, it accurately controls parameters such as compression force and displacement during the test, collects and processes relevant data in real time, and obtains important mechanical performance indicators such as compression strength, elastic modulus, and yield point. These indicators play an indispensable role in the quality control, R&D improvement, and formulation of relevant industry standards for packaging products, and are widely used in papermaking, packaging, building materials, plastics, rubber, and other industries, as well as scientific research institutions and university laboratories.

[0003] However, there are many problems that need to be solved in the current computer-controlled compression testers on the market. Its mechanical transmission parts, such as screws, nuts, clamps, etc., are very prone to wear after long-term and frequent use. The clearance between the screw and nut increases due to wear, which causes deviations in the applied pressure during the transmission process, making it difficult to accurately act on the specimen. This not only seriously affects the repeatability and accuracy of the test results, but also lacks comparability of test data from different batches, and cannot provide a reliable basis for accurate control of product quality; it also causes the instrument to run unstably, generating vibrations and abnormal noise. Therefore, it is necessary to propose a computer-controlled compression tester for packaging product production. Summary of the invention

[0004] In order to solve the problems raised in the above background technology, the present invention proposes a computer-controlled compression tester for packaging product production.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A computer-controlled compression tester for packaging product production, comprising hardware equipment and software system, wherein the hardware equipment comprises a hardware structure, an oiling component, and a control device; The hardware structure includes a base, columns symmetrically arranged on the top surface of the base, and a top plate fixed on the top of the columns. A hydraulic cylinder is provided on the bottom surface of the top plate, and an upper pressure plate is fixedly connected to the movable end of the hydraulic cylinder. The upper pressure plate is slidably matched with the column through a connecting plate. A supporting column in the middle of the top surface of the base supports a supporting plate, and a lower pressure plate matched with the upper pressure plate is provided above the supporting plate. A pressure sensor is provided between the upper pressure plate and the lower pressure plate; the control device is provided on the front end surface of the base and is connected to the pressure sensor, and the oil filling assembly is provided in the connecting plate; The software system includes a data acquisition module, a strength detection module, a feedback control module, and a closed-loop regulation module; the data acquisition module is used to acquire the electrical signals output by the pressure sensor at a set sampling frequency, and convert them into digital signals for storage and processing; The strength detection module is used to analyze and calculate the collected data to obtain various mechanical property parameters of the packaging product; The feedback control module is used to adjust the driving power of the hydraulic cylinder according to the deviation between the actual value measured by the pressure sensor and the preset target value; The closed-loop regulation module performs real-time compensation for the errors caused by mechanical wear and sample characteristic changes on the hardware device by establishing an error compensation model.

[0006] Preferably, the oil adding component includes an oil cavity and an annular liquid cavity opened in the connecting plate, and the annular liquid cavity is communicated with the oil cavity. A plurality of liquid outlets are evenly opened on the inner wall of the annular liquid cavity, sponges are arranged in the liquid outlets, and a monitoring member is also arranged in the oil cavity.

[0007] Preferably, the monitoring member includes a liquid level sensor arranged in the oil cavity, and the liquid level sensor cooperates with the control device, and an alarm lamp matched with the liquid level sensor is arranged on the top surface of the connecting plate.

[0008] Preferably, the data acquisition module adopts an adaptive sampling frequency algorithm to dynamically adjust the sampling frequency according to the severity of the pressure change during the test. Specifically: Take the start moment of the test as the first moment, the current moment as the second moment, and mark the time region between the first moment and the second moment as the test monitoring time zone; Divide the test monitoring time zone into test sub-time zones, identify the pressure values collected by the pressure sensor at any moment in the test sub-time zone, calculate the average value and standard deviation of the pressure values in the test sub-time zone, and assign corresponding time sequence weights to the test sub-time zones in the test monitoring time zone according to the time sequence; Perform weighted processing on the average value and standard deviation of the pressure values in all test sub-time zones in the test monitoring time zone and their corresponding time sequence weights to obtain the pressure change value; When the pressure change value exceeds the set pressure change threshold, trigger the frequency dynamic adjustment operation: Set a sampling frequency range group, including several sampling frequencies; match the pressure change value with the value range of the sampling frequency range group to obtain the corresponding sampling frequency and update the current sampling frequency.

[0009] Preferably, the strength detection module is used to analyze and calculate the collected data to obtain various mechanical property parameters of the packaging product. Specifically: Identify the maximum pressure value Fmax that the packaging product can withstand during the compression process, and pre-measure and determine the contact area between the packaging product and the pressing plate according to the size of the packaging product before the test. Calculate the compression strength based on the maximum pressure value and the contact area; Obtain the initial height L of the packaging product when it is not compressed, set the spring stiffness coefficient of the packaging product. Within the elastic deformation range, the pressure value and the displacement are linearly related. Calculate the elastic modulus based on the spring stiffness coefficient and the initial height; Construct a pressure-displacement curve graph with the pressure value and the displacement value when the packaging product undergoes plastic deformation; Identify the slope of the curve in the pressure-displacement curve graph. When the slope is greater than the preset change threshold, that is, when a non-linear segment appears, it indicates the start of the plastic deformation stage; identify the pressure value in the pressure-displacement curve graph that satisfies the plastic elongation rate reaching the set elongation rate, and calculate the yield strength by calculating the pressure value and the contact area; Obtain the deformation amounts in the transverse and longitudinal directions of the packaging product during the compression process, denoted as the longitudinal strain and the transverse strain, and obtain the longitudinal initial length and the transverse initial length of the packaging product, and thus obtain the Poisson's ratio using a preset formula; Obtain the maximum displacement of the packaging product during the compression process, and calculate the energy absorption capacity by integrating the pressure-displacement curve; Mark the compression strength, spring stiffness coefficient, yield strength, Poisson's ratio, and energy absorption capacity as the mechanical property parameters of the packaging product.

[0010] Preferably, according to the deviation between the actual value measured by the pressure sensor and the preset target value, adjust the driving power of the hydraulic cylinder. Specifically: Obtain the deviation between the actual pressure value measured by the pressure sensor and the preset target pressure value, and calculate the control quantity; adjust the driving power of the hydraulic cylinder in real time through the control quantity.

[0011] Preferably, the control device integrates a data collector, a data processor, a feedback controller, and a closed-loop regulator.

[0012] Preferably, establish an error compensation model to compensate for the errors caused by mechanical wear and sample characteristic changes on the hardware device in real time. Specifically: Obtain historical test data, including the test results of different packaging products under different test conditions. The test results include the mechanical property parameters and time of the packaging product; at the same time, record the usage information of the hardware device, including usage duration, operation times, and maintenance records; Establish an error compensation model using a neural network model based on the usage information of the hardware device, historical data, and the sample characteristics of the packaging product; where the sample characteristics include the size, material, and humidity of the packaging product; Input the test data of the current packaging product and the preset sample characteristic data into the error compensation model, calculate and predict the error value existing in the current test according to the model; calculate the compensation amount according to the predicted error value; convert the calculated compensation amount into the driving parameters of the adjusting hydraulic cylinder, including current and voltage. After the test, compare the actual test result with the expected result to evaluate the error compensation effect; judge whether it is necessary to update and optimize the error compensation model according to whether the evaluated error compensation effect reaches the expected level.

[0013] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows: 1. The present invention combines hardware equipment with a software system. The data acquisition module adaptively adjusts the sampling frequency, accurately captures pressure changes, reduces data redundancy, the strength detection module comprehensively analyzes data, obtains multiple mechanical property parameters, and the feedback control module accurately regulates the driving power of the hydraulic cylinder based on the deviation to ensure the stable progress of the test. The closed-loop adjustment module compensates for errors in real time, improves the test accuracy and repeatability, and overall improves the intelligent level and test reliability of the tester.

[0014] 2. The present invention effectively reduces the friction between the connecting plate and the column by setting an oil adding component, reduces mechanical wear, ensures the accurate transmission of pressure, improves the accuracy of measurement data, and at the same time ensures the stable operation of the instrument, reducing vibration and noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Shows a structural schematic diagram of a front view according to an embodiment of the present invention; Figure 2 Shows a structural schematic diagram of a lower pressing plate according to an embodiment of the present invention; Figure 3 Shows a structural schematic diagram of an upper pressing plate according to an embodiment of the present invention; Figure 4 Shows a structural schematic diagram of an oil adding component according to an embodiment of the present invention; Figure 5 Shows a principle block diagram of a software system according to an embodiment of the present invention.

[0016] Legend Explanation: 1. Base; 2. Column; 3. Top plate; 4. Connecting plate; 5. Lower pressing plate; 6. Upper pressing plate; 7. Hydraulic cylinder; 8. Support plate; 9. Control device; 10. Support column; 11. Pressure sensor; 12. Alarm lamp; 13. Oil cavity; 14. Liquid level sensor; 15. Annular liquid cavity; 16. Sponge; 17. Liquid outlet. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0018] Please refer to Figures 1 - 5 , the present invention provides a computer-controlled compression tester for the production of packaging products, including hardware devices and software systems. The hardware devices include a hardware structure, an oil filling component, and a control device 9; The hardware structure includes a base 1, columns 2 symmetrically arranged on the top surface of the base 1, and a top plate 3 fixed to the top of the columns 2. A hydraulic cylinder 7 is provided on the bottom surface of the top plate 3, and its movable end is fixedly connected to an upper pressure plate 6. The upper pressure plate 6 is slidably matched with the columns 2 through a connecting plate 4. A support column 10 in the middle of the top surface of the base 1 supports a support plate 8. A lower pressure plate 5 cooperating with the upper pressure plate 6 is provided above the support plate 8. A pressure sensor 11 is arranged between the upper pressure plate 6 and the lower pressure plate 5; the control device 9 is arranged on the front end surface of the base 1 and is connected to the pressure sensor 11, and the oil filling component is arranged in the connecting plate 4; through the use of the oil filling component, it is convenient to apply lubricating oil between the connecting plate 4 and the columns 2, reduce the friction between the connecting plate 4 and the columns 2, avoid the increase of the gap between the columns 2 and the connecting plate 4 due to friction, ensure that the applied pressure can be accurately transmitted to the specimen, and ensure the accuracy of the measurement data; at the same time, ensure the stable operation of the computer-controlled compression tester, avoid vibration or noise generation, so as to be beneficial to the use of the computer-controlled compression tester; The software system includes a data acquisition module, a strength detection module, a feedback control module, and a closed-loop adjustment module; the data acquisition module is used to collect the electrical signals output by the pressure sensor 11 at a set sampling frequency and convert them into digital signals for storage and processing; The strength detection module is used to analyze and calculate the collected data to obtain various mechanical property parameters of the packaging product; The feedback control module is used to adjust the driving power of the hydraulic cylinder 7 according to the deviation between the actual value measured by the pressure sensor 11 and the preset target value; The closed-loop adjustment module compensates for the errors caused by mechanical wear and sample characteristic changes on the hardware device in real time by establishing an error compensation model.

[0019] In the present invention, the oil replenishing assembly includes an oil cavity 13 (an oil port is provided on the top surface of the oil cavity 13, and a rubber plug is provided in the oil port) and an annular liquid cavity 15 formed in the connecting plate 4. Both the annular liquid cavity 15 and the oil cavity 13 are filled with lubricating oil for lubricating between the connecting plate 4 and the column 2. The annular liquid cavity 15 is communicated with the oil cavity 13, and a plurality of liquid outlets 17 are uniformly formed on the inner wall of the annular liquid cavity 15. A sponge 16 is provided in the liquid outlet 17, and a monitoring member is further provided in the oil cavity 13. By using the monitoring member, it is convenient to monitor the amount of lubricating oil in the oil cavity 13 and timely add lubricating oil to the oil cavity 13.

[0020] In the present invention, the monitoring member includes a liquid level sensor 14 disposed in the oil cavity 13, and the liquid level sensor 14 cooperates with the control device 9. An alarm lamp 12 cooperating with the liquid level sensor 14 is provided on the top surface of the connecting plate 4.

[0021] The data acquisition module adopts an adaptive sampling frequency algorithm to dynamically adjust the sampling frequency according to the severity of the pressure change during the test. Specifically: Take the start time of the test as the first moment, the current time as the second moment, and mark the time region between the first moment and the second moment as the test monitoring time zone; Divide the test monitoring time zone into test sub-time zones, identify the pressure values collected by the pressure sensor 11 at any moment in the test sub-time zone, calculate the average value and standard deviation of the pressure values in the test sub-time zone, and assign corresponding time sequence weights to the test sub-time zones in the test monitoring time zone in chronological order. It should be noted that the time sequence weights are set in the order of the distance from the current moment. The closer the test sub-time zone is to the current moment, the greater its weight; the farther the test sub-time zone is from the current moment, the smaller its weight. By setting the time sequence weights in this way, the recent data can have a greater influence in the overall analysis, which better meets the timeliness requirements of the data in the actual situation; Perform weighted processing on the average value and standard deviation of the pressure values in all test sub-time zones in the test monitoring time zone and their corresponding time sequence weights to obtain the pressure change value; When the pressure change value exceeds the set pressure change threshold, trigger the frequency dynamic adjustment operation: Set a sampling frequency range group including several sampling frequencies; match the pressure change value with the value range of the sampling frequency range group to obtain the corresponding sampling frequency and update the current sampling frequency.

[0022] It should be noted that the setting of the pressure change threshold needs to consider multiple factors, and the setting basis is as follows: Identify the accuracy and stability of the test equipment; Obtain the texture type of the packaging product, including hard texture, soft texture or special structure; set the texture score for the texture type of the packaging product using the expert scoring method; Set the trend score and the micro-change score; obtain the test requirements and objectives. If the test aims to obtain the performance of the packaging product under micro-pressure changes, select the micro-change score. If it focuses on the overall performance trend of the pressure, select the trend score; where the trend score is greater than the micro-change score; Normalize the accuracy, stability, texture score and trend score or micro-change score of the test equipment to obtain the pressure change threshold, so as to reasonably adjust the sampling frequency in different test scenarios and conditions, and achieve accurate acquisition and analysis of test data.

[0023] In this application, the strength detection module is used to analyze and calculate the collected data to obtain various mechanical property parameters of the packaging product, specifically: Identify the maximum pressure value Fmax that the packaging product can withstand during the compression process, and pre-measure and determine the contact area A between the packaging product and the pressure plate according to the size of the packaging product before the test. Calculate the compression strength S according to the maximum pressure value Fmax and the contact area. The formula is expressed as S = Fmax / A; Obtain the initial height L of the packaging product when it is not compressed, set the spring stiffness coefficient k of the packaging product. Within the elastic deformation range, the pressure value F and the displacement show a linear relationship, that is , calculate the elastic modulus E according to the spring stiffness coefficient and the initial height. The formula is E = kL / A; Among them, the spring stiffness coefficient k can be obtained by linear fitting of the pressure-displacement curve. Specifically, use the least squares method to fit the collected pressure and displacement data to obtain n groups of pressure values Fi and displacement data, and find the minimum k value and b value through . The b value represents the linear intercept term and is a constant term; among them, the visual recognition algorithm is used to obtain the initial height of the packaging product when it is not compressed. This algorithm for identifying the height is a mature existing technology, so it will not be elaborated in this application; Construct a pressure-displacement curve graph with the pressure value and displacement value when the packaging product generates plastic deformation; Identify the slope of the curve in the pressure-displacement curve graph. When the slope is greater than the preset change threshold, that is, when a non-linear segment appears, it means that the plastic deformation stage begins; identify the pressure value Fy in the pressure-displacement curve graph that satisfies the plastic elongation rate reaching the set elongation threshold (such as 0.2%). Calculate the yield strength Sy by calculating the pressure value Fy and the contact area A. The formula is expressed as Sy = Fy / A; Obtain the deformation amounts in the transverse and longitudinal directions of the packaging product during the compression process, denoted as the longitudinal strain and the transverse strain , and obtain the longitudinal initial length of the packaging product and the transverse initial length . Based on this, use a preset formula to obtain the Poisson's ratio ; Obtain the maximum displacement of the packaging product during the compression process . By integrating the pressure-displacement curve, obtain the energy absorption capacity U, and the calculation formula is: , where represents the function of pressure changing with displacement, which can be obtained by fitting the pressure-displacement curve; the upper limit of the integral is the maximum displacement of the packaging product during the compression process , and the lower limit is 0; Mark the compressive strength, spring stiffness coefficient, yield strength, Poisson's ratio, and energy absorption capacity as the mechanical property parameters of the packaging product.

[0024] In this application, according to the deviation between the actual value measured by the pressure sensor 11 and the preset target value, adjust the driving power of the hydraulic cylinder 7, specifically: Obtain the actual pressure value measured by the pressure sensor 11 and the preset target pressure value between the deviations , calculate the control quantity ; where the deviation The calculation formula is , the control quantity The calculation formula is , is the proportional coefficient, which is used to accelerate the response speed of the system and make the system quickly approach the target value, is the integral coefficient, which is used to eliminate the steady-state error of the system and improve the control accuracy, is the differential coefficient, which is used to predict the change trend of the error and suppress the overshoot of the system, represents the integral of the parameter target deviation from the initial time t0 of the time monitoring time zone to the acquisition time t, represents the derivative of the parameter target deviation with respect to time t, and dt represents the control period; Adjust the driving power of the hydraulic cylinder 7 in real time through the control quantity .

[0025] In this application, the control device 9 integrates a data collector, a data processor, a feedback controller, and a closed-loop regulator.

[0026] It should be further noted that in the computer-controlled compression tester for the production of packaging products in this application, the control device 9 serves as the core control unit and bears the operation of the software system. The software system includes a data acquisition module, a strength detection module, a feedback control module, and a closed-loop regulation module, which are deeply integrated inside the control device 9. The data collector, data processor, feedback controller, and closed-loop regulator integrated in the control device 9 cooperate closely with the respective modules of the software system. The data acquisition module collects and processes the signals of the pressure sensor 11 at a set sampling frequency through the data collector of the control device 9; the strength detection module analyzes and calculates the collected data with the help of the data processor; the feedback control module adjusts the driving power of the hydraulic cylinder 7 according to the pressure deviation in cooperation with the feedback controller; the closed-loop regulation module jointly with the closed-loop regulator realizes the real-time compensation of the errors of the hardware devices.

[0027] In this application, an error compensation model is established to compensate for the errors caused by mechanical wear and sample characteristic changes on the hardware devices in real time. Specifically: Obtain historical test data, including the test results of different packaging products under different test conditions. The test results include various mechanical property parameters and time of the packaging products; at the same time, record the usage information of the hardware devices, including usage duration, operation times, and maintenance records. Establish an error compensation model using a neural network model based on the usage information of the hardware devices, historical data, and the sample characteristics of the packaging products; where the sample characteristics include the size, material, and humidity of the packaging products. Input the test data of the current packaging product and the preset sample characteristic data into the error compensation model, and predict the error value existing in the current test according to the model calculation; calculate its compensation amount according to the predicted error value; convert the calculated compensation amount into the driving parameters of the adjusting hydraulic cylinder, including current and voltage. After the test is completed, compare the actual test results with the expected results to evaluate the error compensation effect; judge whether it is necessary to update and optimize the error compensation model according to whether the evaluated error compensation effect reaches the expected level.

[0028] It should be noted that the training data of the neural network model is derived from the sensor data during the operation of the device, covering various parameters such as pressure, temperature, and displacement, as well as the measured values of the corresponding mechanical wear amount; the model architecture of the neural network model adopts a multi-layer perceptron (MLP) architecture, including an input layer, a hidden layer, and an output layer. Input layer: The number of nodes is determined according to the number of input features: In this embodiment, considering the influence of parameters such as pressure, temperature, and displacement on mechanical wear, a total of 6 input layer nodes are set to fully receive relevant data. Hidden layer: A three-layer hidden layer structure is adopted, with the number of nodes in each layer being 16, 8, and 4 respectively. This setting can not only ensure the learning ability of the model but also avoid the overfitting problem caused by too many nodes. The activation function of the hidden layer is selected as the ReLU function, and its mathematical expression is f(x) = max(0, x). The ReLU function not only has simple calculations but also can effectively solve the gradient disappearance problem and accelerate the convergence speed of the model. Here, x represents the input value of the function, which is the weighted sum result transmitted from the neurons in the previous layer. Output layer: The number of nodes in the output layer is 1, which is used to output the compensation value of the mechanical wear error.

[0029] The working principle of a computer-controlled measurement and control compression tester for packaging products production proposed in this application is as follows: Hardware cooperation working principle: When the test starts, the operator starts the hydraulic cylinder 7, and the movable end of the hydraulic cylinder 7 drives the upper pressure plate 6 to move downward. The upper pressure plate 6 slides along the column 2 through the connecting plate 4 to ensure the smoothness of the movement. During this process, the lubricating oil in the oil filling component flows from the oil cavity 13 through the liquid outlet 17 of the annular liquid cavity 15 and is slowly applied to the column 2 through the sponge 16, reducing the friction between the connecting plate 4 and the column 2 and reducing mechanical wear. The pressure sensor 11 measures the pressure between the upper pressure plate 6 and the lower pressure plate 5 in real time and transmits the pressure signal to the control device 9. The data collector in the control device 9 receives the electrical signal from the pressure sensor 11 and converts it into a digital signal, providing a basis for subsequent data processing and control.

[0030] Among them, when the upper pressure plate 6 moves, it will cause the lubricating oil in the oil cavity 13 to be applied to the column 2 through the sponge 16, reducing the friction between the column 2 and the connecting plate 4. When the lubricating oil in the oil cavity 13 drops to the preset oil level, the liquid level sensor 14 is triggered to collect the oil shortage signal and send the oil shortage signal to the control device 9. The control device 9 controls the alarm lamp 12 to be powered on to work, reminding the operator that the lubricating oil in the oil cavity 13 is insufficient, so as to facilitate timely adding lubricating oil to the oil cavity 13, avoiding the aggravation of mechanical wear and equipment failure caused by insufficient lubricating oil, ensuring the continuous and stable operation of the equipment, and reducing the downtime caused by equipment failure.

[0031] Software system working principle: Data acquisition module: The data acquisition module continuously monitors the pressure change during the test. By dividing the test monitoring time zone and the test sub-time zone, calculating the average value and standard deviation of the pressure values in each sub-time zone, and combining with the time series weight to obtain the pressure change value. When the pressure change value exceeds the set threshold, a suitable sampling frequency is selected from the preset sampling frequency range group to increase or decrease the data acquisition frequency, so as to more accurately capture the pressure change trend and avoid unnecessary data redundancy at the same time.

[0032] Strength detection module: As the test progresses, the strength detection module continuously receives the pressure data transmitted by the data acquisition module. According to the pre-measured dimensions and contact area of the packaging product, as well as information such as the initial height obtained through the visual recognition algorithm, various mechanical property parameters of the packaging product are calculated. In the elastic deformation stage, the spring stiffness coefficient is obtained by fitting the pressure-displacement curve, and then the elastic modulus is calculated; the yield strength is calculated by identifying the non-linear section in the pressure-displacement curve graph and the pressure value corresponding to a specific plastic elongation rate; the transverse and longitudinal deformation amounts are measured, and the Poisson's ratio is calculated in combination with the initial length; the energy absorption capacity is calculated by integrating the pressure-displacement curve.

[0033] Feedback control module: The feedback control module obtains the actual pressure value measured by the pressure sensor 11 and the preset target pressure value in real time, and calculates the deviation between the two. According to the deviation, the PID control algorithm is used to calculate the control quantity. The proportional coefficient enables the system to quickly respond to the deviation, the integral coefficient is used to eliminate the steady-state error, the derivative coefficient predicts the change trend of the error, and suppresses the overshoot. By adjusting the control quantity, the driving power of the hydraulic cylinder 7 is changed in real time, so that the actual pressure value is adjusted towards the preset target value, realizing precise control of the compression process.

[0034] Closed-loop adjustment module: The closed-loop adjustment module collects historical test data and hardware device usage information before the test, combines the sample characteristics of the packaging product, and uses a neural network model to establish an error compensation model. During the test, the current test data and the preset sample characteristic data are input into the model to predict the possible error values. According to the predicted error values, the compensation amount is calculated, and the compensation amount is converted into an instruction to adjust the driving parameters (such as current, voltage) of the hydraulic cylinder 7. After the test, the actual test results are compared with the expected results to evaluate the error compensation effect. If the error compensation effect does not meet the expectation, the error compensation model is updated and optimized according to the evaluation results to provide more accurate error compensation for the next test.

[0035] The above description of the embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A computer-controlled compression tester for packaging product production, including hardware equipment and software system, characterized in that: The hardware device includes a hardware structure, an oil filling component, and a control device (9); The hardware structure comprises a base (1), a column (2) symmetrically arranged on the top surface of the base (1), and a top plate (3) fixed on the top of the column (2); a hydraulic cylinder (7) is provided on the bottom surface of the top plate (3), and an upper pressure plate (6) is fixedly connected to the movable end of the hydraulic cylinder (7); the upper pressure plate (6) is slidably matched with the column (2) through a connecting plate (4); a supporting column (10) in the middle of the top surface of the base (1) supports a supporting plate (8); a lower pressure plate (5) matched with the upper pressure plate (6) is provided above the supporting plate (8); a pressure sensor (11) is provided between the upper pressure plate (6) and the lower pressure plate (5); the control device (9) is provided on the front end surface of the base (1) and is connected to the pressure sensor (11); the oil filling assembly is provided in the connecting plate (4); The software system comprises a data acquisition module, an intensity detection module, a feedback control module, and a closed-loop regulation module; the data acquisition module is used to collect the electrical signal output by the pressure sensor (11) at a set sampling frequency, and convert it into a digital signal for storage and processing; The strength detection module is used to analyze and calculate the collected data to obtain various mechanical performance parameters of the packaging product; The feedback control module is used to adjust the driving power of the hydraulic cylinder (7) according to the deviation between the actual value measured by the pressure sensor (11) and the preset target value; The closed-loop adjustment module compensates in real time for errors caused by mechanical wear on hardware equipment and sample characteristic changes by establishing an error compensation model.

2. A computer-controlled compression tester for packaging product production according to claim 1, characterized in that: The oil filling assembly comprises an oil chamber (13) and an annular liquid chamber (15) formed in the connecting plate (4), wherein the annular liquid chamber (15) is in communication with the oil chamber (13), a plurality of liquid outlets (17) are evenly formed on the inner wall of the annular liquid chamber (15), a sponge (16) is provided in the liquid outlet (17), and a monitoring component is also provided in the oil chamber (13).

3. A computer-controlled compression tester for packaging product production according to claim 2, characterized in that: The monitoring component comprises a liquid level sensor (14) disposed in the oil chamber (13), and the liquid level sensor (14) cooperates with the control device (9), and an alarm light (12) cooperating with the liquid level sensor (14) is provided on the top surface of the connecting plate (4).

4. The computer-controlled compression tester for packaging product production according to claim 1, characterized in that: The data acquisition module uses an adaptive sampling frequency algorithm to dynamically adjust the sampling frequency according to the severity of the pressure change during the test, specifically: The time when the test starts is taken as the first time, the current time is taken as the second time, and the time area between the first time and the second time is marked as the test monitoring time zone; Divide the test monitoring time zone into test time zones, identify the pressure value collected by the pressure sensor (11) at any time in the test time zone, calculate the average value and standard deviation value of the pressure value in the test time zone, and assign corresponding time sequence weights to the test time zones in the test monitoring time zone in chronological order; The average value and standard deviation of the pressure values ​​in all test time zones in the test monitoring time zone are weighted with their corresponding time series weights to obtain the pressure change value; When the pressure change value exceeds the set pressure change threshold, the frequency dynamic adjustment operation is triggered: A sampling frequency range group is set, including several sampling frequencies; the pressure change value is matched with the value range of the sampling frequency range group to obtain the corresponding sampling frequency, and the current sampling frequency is updated.

5. The computer-controlled compression tester for packaging product production according to claim 1, characterized in that: The strength detection module is used to analyze and calculate the collected data to obtain various mechanical performance parameters of the packaging product, specifically: Identify the maximum pressure value Fmax that the packaging product can withstand during the compression process, and pre-measure and determine the contact area between the packaging product and the pressing plate according to the size of the packaging product before the test, and calculate the compression strength based on the maximum pressure value and the contact area; Obtain the initial height L of the packaging product when it is not compressed, set the spring stiffness coefficient of the packaging product, within the elastic deformation range, the pressure value and the displacement are linearly related, and calculate the elastic modulus based on the spring stiffness coefficient and the initial height; The pressure value and displacement value of the packaging product when it undergoes plastic deformation constitute a pressure-displacement curve; Identify the slope of the curve in the pressure-displacement curve. When the slope is greater than the preset change threshold, that is, when a nonlinear segment appears, it indicates that the plastic deformation stage has begun. Identify the pressure value in the pressure-displacement curve that satisfies the plastic elongation rate to reach the set elongation rate, and calculate the yield strength by combining the pressure value with the contact area. Obtain the transverse and longitudinal deformations of the packaging product during the compression process, recorded as the longitudinal strain and the transverse strain, and obtain the longitudinal initial length and the transverse initial length of the packaging product, and use the preset formula to obtain the Poisson's ratio; Obtain the maximum displacement of the packaging product during the compression process, and obtain the energy absorption capacity by integrating the pressure-displacement curve; The compression strength, spring stiffness coefficient, yield strength, Poisson's ratio and energy absorption capacity are marked as the mechanical performance parameters of the packaging products.

6. The computer-controlled compression tester for packaging product production according to claim 1, characterized in that: According to the deviation between the actual value measured by the pressure sensor (11) and the preset target value, the driving power of the hydraulic cylinder (7) is adjusted, specifically: The deviation between the actual pressure value measured by the pressure sensor (11) and the preset target pressure value is obtained, and the control amount is calculated; and the driving power of the hydraulic cylinder (7) is adjusted in real time according to the control amount.

7. The computer-controlled compression tester for packaging product production according to claim 1, characterized in that: The control device (9) integrates a data collector, a data processor, a feedback controller and a closed-loop regulator.

8. The computer-controlled compression tester for packaging product production according to claim 1, characterized in that: By establishing an error compensation model, the errors caused by mechanical wear on hardware equipment and changes in sample characteristics are compensated in real time. Specifically: Obtain historical test data, including test results of different packaging products under different test conditions. The test results include various mechanical performance parameters and time of packaging products. At the same time, record the usage information of hardware equipment, including usage time, number of operations, and maintenance records. An error compensation model is established using a neural network model based on the usage information and historical data of the hardware equipment and the sample characteristics of the packaging products; wherein the sample characteristics include the size, material, and humidity of the packaging products; Input the test data of the current packaging product and the preset sample characteristic data into the error compensation model, and predict the error value existing in the current test according to the model calculation; calculate the compensation amount according to the predicted error value; convert the calculated compensation amount into the driving parameters of the hydraulic cylinder, including current and voltage; After the test, the actual test results are compared with the expected results to evaluate the error compensation effect; based on whether the evaluated error compensation effect reaches the expected level, it is determined whether the error compensation model needs to be updated and optimized.

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