A double-sided adhesive tape processing system and method based on PLC

Abstract

The application relates to the technical field of industrial automation control and adhesive tape processing, in particular to a double-sided adhesive tape processing system and method based on PLC, which comprises the following: a multi-dimensional data acquisition module: real-time acquisition of tension, encoder linear speed, roll diameter, torque and temperature, and utilization of motor torque to check the confidence of a sensor; a rheological property analysis module: combination of viscoelastic model parameters and tension values to calculate instantaneous tensile strain; a stress relaxation prediction module: calculation of a physical relaxation time window based on the encoder linear speed and transmission distance, combination of temperature and strain to generate a residual stress prediction value through rheological dynamics operation; a risk assessment decision module: comparison of the prediction value with a glue cold flow threshold value to generate a stress risk index quantifying glue overflow and deformation risk; and an adaptive control module: generation of a nonlinear tension reconstruction or speed intervention instruction based on the index; the application eliminates the phenomena of glue overflow and raised bumps after the winding of the adhesive tape, and establishes a closed-loop control system based on the rheological state of the material.

Description

Technical Field

[0001] This invention relates to the field of industrial automation control and adhesive tape processing technology, specifically to a PLC-based double-sided adhesive tape processing system and method. Background Technology

[0002] In the double-sided tape processing and production environment, pressure-sensitive adhesive materials have significant viscoelastic and nonlinear rheological characteristics, and their physical state is greatly affected by the combined effects of ambient temperature, stretching rate and transmission distance. Existing control schemes generally adopt a single feedback control architecture based on tension sensors, that is, the PID algorithm only focuses on whether the tension value at the current moment is maintained within the set range. This traditional mode ignores the stress relaxation behavior and speed hardening effect of polymer materials during high-speed stretching and transmission, and cannot detect the hidden risk that the internal residual stress has exceeded the cold flow threshold of the glue even though the tension value is within the normal range. Especially under extreme conditions such as low temperature and high speed, due to the lack of quantitative analysis of the rheological properties of the adhesive layer and the stress decay process, the finished product is very prone to time-sensitive quality defects such as glue overflow in the roll, end face ribbing and interlayer deformation during static storage. Moreover, the existing system is unable to identify and actively intervene in such lag risks from the physical root cause. Therefore, how to overcome the limitations of simple tension numerical control and construct a real-time residual stress prediction and adaptive control system based on the material rheological state to eliminate potential quality problems after winding has become an urgent technical problem to be solved. Summary of the Invention

[0003] The purpose of this invention is to provide a PLC-based double-sided tape processing system and method, avoiding the problems of adhesive overflow and deformation after winding caused by focusing only on the current tension value and ignoring excessive residual stress. Furthermore, it facilitates predictive adjustment and closed-loop control of processing parameters based on material rheological property analysis. Specifically, the technical solution of this invention is as follows: A PLC-based double-sided tape processing system includes: The multi-dimensional data acquisition module is configured to acquire tension sensor values, encoder linear speed, current roll diameter, motor torque, and adhesive surface temperature in real time during the double-sided tape processing process, in order to generate a real-time working condition state vector. The rheological property analysis module is configured to calculate the instantaneous tensile strain of the double-sided tape under the current traction state based on preset viscoelastic model parameters and the tension sensor values ​​in the real-time working condition state vector. The stress relaxation prediction module is configured to calculate the physical relaxation time window based on the encoder linear speed and the preset inter-roller transfer distance, and combine the adhesive layer surface temperature and the instantaneous tensile strain to generate the predicted value of residual stress when reaching the winding position through rheological dynamics calculation. The risk assessment and decision-making module is configured to compare the predicted residual stress value with the preset adhesive cold flow threshold to generate a stress risk index that quantifies the risk of adhesive overflow and deformation within the tape roll. The adaptive control module is configured to generate nonlinear tension reconstruction commands or speed intervention commands based on the stress risk index, and send the commands to the servo drive unit to adjust the machining parameters.

[0004] Preferably, the rheological property analysis module includes: The parameter mapping unit is used to call the elastic modulus and viscosity coefficient that match the current processed material from the PLC formula library as the viscoelastic model parameters; The strain calculation unit is used to calculate the instantaneous tensile strain based on the encoder linear velocity and tension sensor value in the real-time working condition state vector, using a nonlinear Hooke's law correction algorithm.

[0005] Preferably, the stress relaxation prediction module includes: The time-domain conversion unit is used to divide the preset inter-roller transmission distance by the encoder linear velocity in the real-time operating condition state vector to obtain the physical relaxation time window. The dynamic simulation unit is used to input the instantaneous tensile strain, the physical relaxation time window, and the adhesive layer surface temperature into a preset Maxwell or Kelvin-Voigt rheological model to simulate the stress decay process and output the predicted value of the residual stress.

[0006] Preferably, the risk assessment decision module includes: The pressure distribution modeling unit is configured to predict the radial pressure distribution between the winding layers based on the current roll diameter and the predicted residual stress value. The threshold determination unit is configured to determine whether the maximum value of the radial pressure distribution exceeds the glue cold flow threshold, and to calculate the stress risk index based on the amplitude or integral area exceeding the threshold.

[0007] Preferably, the adaptive control module executes the following control logic: If the stress risk index is less than or equal to a preset safety value, an instruction to maintain the current process is generated; If the stress risk index is greater than the safety value and less than or equal to the critical value, the nonlinear tension reconstruction instruction is generated. The nonlinear tension reconstruction instruction is used to generate a variable tension curve based on an equal residual stress target. If the stress risk index is greater than the critical value, the speed intervention command is generated. The speed intervention command is used to reduce the encoder linear speed to extend the physical relaxation time window.

[0008] Preferably, the multidimensional data acquisition module includes: The tension detection unit includes pressure sensors installed on both sides of the floating roller for collecting the tension sensor values. An environmental sensing unit includes an infrared temperature sensor pointing towards the surface of the tape, used to collect the surface temperature of the adhesive layer; The motion acquisition unit includes an absolute encoder for a servo motor, used to acquire the encoder's linear velocity and the current roll diameter.

[0009] Preferably, the adaptive control module further includes: The feedback correction unit is used to calculate the rate of change of the predicted residual stress value and dynamically adjust the gain parameter of the PID control loop according to the rate of change.

[0010] A PLC-based method for processing double-sided adhesive tape includes the following steps: S1. Obtain the tension sensor value, encoder linear speed, current roll diameter and adhesive surface temperature during the double-sided tape processing to generate a real-time working condition state vector. S2. Based on the preset viscoelastic model parameters and the tension sensor value in the real-time working condition state vector, calculate the instantaneous tensile strain of the double-sided tape. S3. Based on the physical relaxation time window determined by the encoder linear velocity, simulate the stress attenuation behavior of the tape during transmission and generate a residual stress prediction value. S4. Compare the predicted residual stress value with the preset glue cold flow threshold to generate a stress risk index. S5. Based on the stress risk index, generate nonlinear tension reconstruction instructions or speed intervention instructions to achieve predictive control of winding quality.

[0011] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention breaks through the limitation of traditional control that only focuses on the current tension value and can identify hidden quality risks. Through rheological characteristic analysis and stress relaxation prediction module, the system combines real-time working condition state vector and viscoelastic model parameters to calculate the predicted value of residual stress when reaching the winding position. This enables the system to actively warn when the tension value is normal but the internal stress is too large, eliminating the hidden danger of adhesive overflow and deformation of the tape during static storage from the physical source. 2. This invention constructs an adaptive defense system that coordinates tension and speed to ensure processing quality under extreme working conditions; the adaptive control module automatically generates nonlinear tension reconstruction commands or speed intervention commands based on the stress risk index classification; when the risk is controllable, stress is reduced by optimizing the tension curve; when the risk is critical, the physical relaxation time window is extended by reducing the encoder linear speed, ensuring that the material has enough time to release internal stress and preventing cold flow. 3. This invention significantly improves the physical realism of the control model through multi-dimensional data acquisition and nonlinear algorithm correction. The system uses an infrared temperature sensor to obtain the surface temperature of the adhesive layer and dynamically calls material parameters in conjunction with the parameter mapping unit. At the same time, the strain calculation unit uses a nonlinear Hooke's law correction algorithm to solve the instantaneous tensile strain, which effectively compensates for the speed hardening effect of the pressure-sensitive adhesive under high-speed stretching, and provides an accurate input benchmark for subsequent relaxation prediction. 4. This invention achieves quantitative assessment of internal quality risks in winding; the pressure distribution modeling unit in the risk assessment decision module can predict the radial pressure distribution between winding layers based on the current roll diameter, and the threshold determination unit generates a stress risk index by comparing the cold flow threshold of the adhesive; this mechanism transforms abstract rheological data into intuitive quantitative indicators, which can not only assess the instantaneous risk of exceeding the standard, but also reflect the cumulative destructive effect of the exceeding stress, providing a basis for intelligent decision-making. Attached Figure Description

[0012] The present invention will be further explained below with reference to the accompanying drawings and embodiments: Figure 1 This is a flowchart of the method of the present invention; Figure 2 This is a structural diagram of the system of the present invention. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0014] Example 1: Please see Figure 1 A PLC-based double-sided tape processing system includes: a multi-dimensional data acquisition module configured to acquire tension sensor values, encoder linear speed, current roll diameter, motor torque and adhesive surface temperature in real time during the double-sided tape processing process, so as to generate a real-time working condition state vector. The rheological property analysis module is configured to calculate the instantaneous tensile strain of the double-sided tape under the current traction state based on the preset viscoelastic model parameters and the tension sensor values ​​in the real-time working condition state vector. The stress relaxation prediction module is configured to calculate the physical relaxation time window based on the encoder linear speed and the preset inter-roller transfer distance, and combine the adhesive surface temperature and instantaneous tensile strain to generate the predicted value of residual stress when reaching the winding position through rheological dynamics calculation. The risk assessment and decision-making module is configured to compare the predicted residual stress value with the preset glue cold flow threshold to generate a stress risk index that quantifies the risk of glue overflow and deformation in the tape roll. The adaptive control module is configured to generate nonlinear tension reconstruction commands or speed intervention commands based on the stress risk index, and send the commands to the servo drive unit to adjust the machining parameters.

[0015] This embodiment addresses the core pain point of time-sensitive quality issues in the double-sided tape processing industry by constructing a PLC control system with an embedded rheological model. The multi-dimensional data acquisition module, serving as the system's sensing front end, synchronously acquires data in real time via an industrial fieldbus to build a digital twin foundation and generate a real-time operating condition vector. This vector includes tension sensor values, encoder linear speed, current roll diameter, motor torque, and adhesive layer surface temperature. To ensure the physical authenticity of the input data, motor torque is used to perform online confidence verification of the tension sensor. The system incorporates a torque-tension observer model.

[0016] in, For real-time motor torque, The preset mechanical transmission efficiency is 0.9-0.95. The reduction ratio; real-time system monitoring. If the deviation exceeds the preset fault tolerance threshold, such as 15% of the set tension, and continues for a certain period of time, the system will mark the current working condition vector as invalid and trigger a sensor fault alarm, thereby preventing erroneous data from contaminating subsequent rheological analysis calculations. Among these, the surface temperature parameter of the adhesive layer is crucial, aiming to solve the problem of the significant nonlinear change in viscosity of pressure-sensitive adhesive materials with temperature. The rheological property analysis module calculates the instantaneous tensile strain of the double-sided tape under external force at the moment it leaves the unwinding roller or coating head, based on preset viscoelastic model parameters and combined with real-time collected tension data. The stress relaxation prediction module acts as the system's virtual rheologist. Based on the encoder linear speed and the preset inter-roller transfer distance, it calculates the physical relaxation time window and combines temperature and strain data to simulate the slippage and unwinding process of the tape molecular chains through rheological dynamics calculations, generating the predicted value of residual stress when the tape reaches the winding position. Based on this, the risk assessment and decision-making module compares the predicted value with the preset glue cold flow threshold to generate a stress risk index; the adaptive control module responds to the change of the index and generates corresponding control commands to adjust the processing parameters. This embodiment breaks through the limitation of traditional control that only focuses on the current tension value by introducing rheological property analysis and stress relaxation prediction. The system can identify hidden risks of normal tension values ​​but excessive residual stress under extreme working conditions such as low temperature and high speed, and actively generate intervention commands, thereby eliminating the phenomenon of tape cracking and glue overflow after tape winding, and establishing a closed-loop control system based on the material rheological state.

[0017] Example 2: The rheological property analysis module includes: a parameter mapping unit, which calls the elastic modulus and viscosity coefficient matching the current processed material from the PLC recipe library as viscoelastic model parameters; and a strain calculation unit, which calculates the instantaneous tensile strain based on the encoder linear velocity and tension sensor values ​​in the real-time working condition state vector using a nonlinear Hooke's law correction algorithm.

[0018] This embodiment details the specific implementation of the rheological property analysis module, especially how to obtain accurate strain data; the parameter mapping unit calls the elastic modulus and viscosity coefficient that match the current processed material from the PLC formula library; this process is implemented through a multidimensional lookup table preset in the PLC memory, using temperature as the index, and dynamically outputs the current material parameters; To eliminate the stepped quantization error caused by discrete formulation data, the parameter mapping unit performs real-time linear interpolation: Let the currently acquired real-time adhesive layer surface temperature be... The two adjacent temperature nodes in the formula library are ,satisfy The corresponding elastic modulus is The current output modulus The calculation is as follows:

[0019] viscosity coefficient The same interpolation logic is also used; this operation ensures that the material parameters of the input model change continuously and smoothly with temperature, avoiding control system oscillations caused by table lookup jumps; the strain calculation unit calculates the instantaneous tensile strain based on the encoder linear velocity and tension sensor values ​​in the real-time operating condition state vector, using a nonlinear Hooke's law correction algorithm; this algorithm considers the strain hardening effect of the tape under high-frequency tension, and the specific correction calculation is as follows:

[0020] in, The source is a multi-dimensional data acquisition module, and its physical meaning is the real-time acquired tension sensor value, with the unit being N; The source is a preset from the PLC recipe library; its physical meaning is the cross-sectional area of ​​the tape, in mm. 2 ; The source is the parameter mapping unit, and the subscript here is... Characterizes temperature-related variables, with the physical meaning of elastic modulus at the current temperature, and the unit is MPa·mm; The source is a multi-dimensional data acquisition module, and its physical meaning is the encoder linear velocity, with the unit being m / min; The data comes from materials laboratory measurements. The specific method involves using a universal testing machine with a constant temperature chamber to perform multiple sets of uniaxial tensile tests on the same material at different tensile rates, covering a process range from 10 m / min to 300 m / min. The secant modulus change rate before the yield point is then extracted and fitted. The physical meaning is the velocity hardening coefficient, and its dimension is set as the reciprocal of velocity, for example, min / m, to ensure... The dimensional consistency of the terms makes the velocity term additive with the constant 1; This embodiment modifies Hooke's law by introducing a rate hardening coefficient, effectively compensating for the increase in stiffness exhibited by polymer materials under high-speed stretching. This technique makes the calculated initial strain closer to the real physical state, providing an accurate input benchmark for subsequent relaxation prediction and avoiding prediction deviations caused by model simplification.

[0021] Example 3: The stress relaxation prediction module includes: a time-domain conversion unit, which divides the preset inter-roller transfer distance by the encoder linear velocity in the real-time operating condition state vector to obtain the physical relaxation time window; and a dynamic simulation unit, which inputs the instantaneous tensile strain, physical relaxation time window and adhesive surface temperature into a preset Maxwell or Kelvin-Voigt rheological model to simulate the stress decay process and output the predicted residual stress value.

[0022] This embodiment details how the stress relaxation prediction module achieves decoupling calculations between time and stress; the time-domain conversion unit performs spatiotemporal mapping, using linear kinematic formulas to convert the preset inter-roller transmission distance... Divide by the encoder linear velocity in the real-time operating condition state vector The physical relaxation time window is calculated as follows:

[0023] This time window This characterizes the actual time it takes for a point on the tape to travel from a stress point, such as the coating traction point, to the winding contact point. The dynamic simulation unit inputs instantaneous tensile strain, physical relaxation time window, and adhesive surface temperature into a preset Maxwell rheological model. This unit aims to simulate the stress decay process of the tape and output predicted residual stress values. The specific calculation logic is as follows:

[0024] in, To represent in terms of natural constants , approximately equal to 2.718, is an exponential function with base 2.718; The index here is for the output variable on the left. Represents the residual state, and its physical meaning is the predicted value of residual stress when the winding position is reached; The source is the rheological property analysis module, and the subscript is here. This represents temperature-related terms, and its physical meaning is the elastic modulus at the current temperature. The source is the rheological property analysis module, and the physical meaning is instantaneous tensile strain; The source is the calculation result of the time domain conversion unit, and the unit is seconds. Here, the multiplier of 60 is used to convert the calculation result in m / min velocity unit to seconds to match the time base of the rheological model. The source is a calculated value; the subscript here is... The temperature-related term refers to the viscosity coefficient retrieved from the PLC recipe library by the parameter mapping unit. With elastic modulus The ratio, i.e. The physical meaning is the relaxation time constant, which reflects the material's ability to eliminate internal stress quickly. This embodiment constructs a virtual time channel within the PLC, revealing the physical mechanism that faster speeds lead to shorter relaxation times, resulting in greater residual stress on the tape when it reaches the winding point. This module quantifies the impact of production speed on the final internal stress of the product, providing a solid theoretical basis for subsequent control strategies.

[0025] Example 4: The risk assessment decision module includes: a pressure distribution modeling unit, configured to predict the radial pressure distribution between winding layers based on the current roll diameter and the predicted residual stress; and a threshold determination unit, configured to determine whether the maximum value of the radial pressure distribution exceeds the glue cold flow threshold, and to calculate the stress risk index based on the amplitude or integral area exceeding the threshold.

[0026] This embodiment details how the risk assessment and decision-making module quantifies quality risks; the pressure distribution modeling unit predicts the radial pressure distribution between winding layers based on the current roll diameter and the predicted residual stress value, using the discretized form of the Altmann winding equation. This discretization is specifically implemented in the PLC as a finite difference iterative algorithm: To eliminate ambiguity in the data structure description, the system constructs a structure array Node, where each element... The first is strictly encapsulated Layer status information, including cumulative radial pressure and the historical modulus when this layer was involved. That is, the real-time elastic modulus corresponding to the moment when this layer is the outermost layer and is involved. When a new layer of tape is wound in, all internal nodes are updated using the force balance equation, indexing... Traverse from 1 to radial pressure increment The specific iterative update algorithm follows the anisotropic decay model, and its calculation formula is as follows:

[0027] in, For the current new involvement layer to the internal first The pressure increment generated by the layer The current volume diameter, For the first Layer radius, For tape thickness, This represents the predicted residual stress value; the exponent term in the formula uses... Instead of the current surface modulus The aim is to reflect the different stiffness characteristics of different layers due to the different temperatures at the time of entrapment; In the formula Represents the radial elastic modulus, which is related to the tangential modulus, i.e., the historical modulus. Through anisotropy coefficient The correlation is calculated using the following formula:

[0028] Parameters here The physical meaning of is the ratio of the tangential elastic modulus to the radial elastic modulus of the tape, reflecting the degree of anisotropy of the winding structure; due to the presence of trace amounts of air between the tape layers and the flexibility of the adhesive layers, the radial modulus is much smaller than the tangential modulus, therefore The value is always greater than 1; in this embodiment, It is a dimensionless constant, that is, the ratio of the tangential elastic modulus to the radial elastic modulus of the tape. It is set as a preset constant, with a typical value of 20-50. This value is determined by sampling and conducting radial compression and tangential tensile tests to determine the modulus ratio and then entering it into the PLC formula library. This setting leads to the exponential term It is a positive value, but due to the base The result of this positive exponentiation operation is always less than 1, thus mathematically correctly characterizing the physical attenuation characteristics of pressure transmission from the outside to the inside, which conforms to the definition of the anisotropic entrainment model; after the calculation is completed, the system performs an accumulation operation. and the new pressure on the current layer Approximate initial value, and current modulus The pressure distribution matrix is ​​dynamically changed with the roll diameter and stored in the structure array. The threshold determination unit determines whether the maximum value of the radial pressure distribution exceeds the preset glue cold flow threshold. This threshold refers to the critical stress value that causes the glue to flow irreversibly during static storage. To ensure the objectivity and feasibility of this key parameter, this embodiment discloses its specific experimental measurement method: Samples of the same batch of adhesive are placed in a rotational rheometer, such as the Anton Paar MCR series, using a parallel plate clamp with a 1mm gap. Creep scanning in stress-controlled mode is performed at the standard storage temperature, typically 23°C. Shear stress is increased incrementally in increments of 5 Pa, starting from 10 Pa, with each increment held for 300 seconds. The creep compliance is defined as... In logarithmic coordinates, it no longer increases linearly with time, but instead exhibits exponential and rapid growth, i.e. The stress value at that time is the glue cold flow threshold. The system calculates the stress risk index based on the amplitude or integral area exceeding the threshold. If amplitude is chosen as the evaluation metric, the calculation logic in the default mode is as follows:

[0029] in, For the calculation result, the subscript 'r' here represents risk, and its physical meaning is the stress risk index; For the variable here This refers to the Node array output by the aforementioned pressure distribution modeling unit. For each member, the maximum value is taken, and the unit is MPa·mm; The source is a preset value. Here, the subscript t represents the threshold, which physically means the glue cold flow threshold, and the unit is MPa·mm. Furthermore, for thin film materials sensitive to stress concentration, the threshold determination unit is also equipped with an integral area evaluation mode; this mode aims to assess the cumulative destructive effect of excessive stress, and its calculation logic adopts a discretized trapezoidal integral algorithm, the calculation formula of which is:

[0030] in, The integral exponent for the stress exceeding the standard is expressed in MPa·mm; specifically, for the starting point of the summation... Boundary conditions involved and The system defines them as the initial pressure on the surface of the winding core, initialized to 0MPa or core pre-tightening, and the radius of the empty core, to ensure the physical integrity of the integration interval. This indicator, in a physical sense, characterizes the total excess expansion force accumulated per unit width within the winding, directly reflecting the magnitude of the potential energy leading to uneven end faces or ridge breakage; this indicator can distinguish the risk difference between peak-type short-term exceedances and plateau-type continuous exceedances. If the energy exceeds the preset destructive energy threshold, it is also considered high risk; This embodiment transforms abstract stress data into intuitive risk percentages or energy integral values; when the risk index is greater than zero or the integral value exceeds the limit, it clearly indicates that although the current process parameters are within the allowable range of the equipment, they have exceeded the physical bearing limit of the material; this module gives the control system the ability to provide quality early warnings.

[0031] Example 5: The adaptive control module executes the following control logic: if the stress risk index is less than or equal to the preset safety value, it generates an instruction to maintain the current process; If the stress risk index is greater than the safety value and less than or equal to the critical value, a nonlinear tension reconstruction instruction is generated. The nonlinear tension reconstruction instruction is used to generate a variable tension curve based on the target of equal residual stress. If the stress risk index is greater than the critical value, a speed intervention command is generated. The speed intervention command is used to reduce the encoder linear speed to extend the physical relaxation time window.

[0032] This embodiment elaborates on the hierarchical execution logic of the adaptive control module, which is the key to achieving predictive control; the system monitors the stress risk index in real time; the preset safety value is usually set to 0%, which requires the internal pressure of the winding to be completely lower than the cold flow threshold. The critical value is not a static empirical value, but rather represents the minimum risk limit that the current equipment can achieve by adjusting the tension to the physical lower limit of the equipment while maintaining its current production capacity, i.e., strictly keeping the current encoder linear speed constant. To achieve dynamic quantification of this boundary, the system performs the following closed-loop calculation: 1. Physical lower limit estimation: Calculate the minimum stable tension under the current roll diameter based on the motor's rated parameters. The calculation formula is as follows:

[0033] in, The rated torque of the motor. The minimum torque output efficiency of the servo system at low speeds is typically set to 0.05-0.1. This parameter is obtained through static friction torque testing of the servo motor: under no-load conditions, the torque command is gradually increased from 0 until the motor begins to nibble, and the ratio of this torque value to the rated torque is recorded as the lower limit of efficiency to ensure that the calculated tension is sufficient to overcome the static friction of the system; it should be clarified here that... Although derived based on static friction characteristics, it is used in this calculation step as the lower boundary constraint of tension at the current production speed to evaluate the maximum tension adjustment potential under conditions without deceleration. The reason for using static friction efficiency As a constraint benchmark in dynamic production, it is based on the worst-case principle: the static friction of the system is usually greater than the dynamic friction. If the lower limit of tension is sufficient to overcome the static friction, it will inevitably overcome the resistance in dynamic operation. This physically ensures that the tension control will not be dead or out of control due to system resistance at any extremely low set value, and ensures the executability of the tension reconfiguration command. For reduction ratio; Limit state mapping: Substitute into the rheological property analysis module to calculate the limiting low strain at the current velocity. And combined with the stress relaxation model, the theoretical minimum residual stress is predicted. ; Dynamic threshold generation: Substitute the values ​​into the risk assessment and decision-making module to calculate the corresponding risk index. The result of this calculation is the current dynamic critical value. When the stress risk index is less than or equal to the preset safety value, the system determines that the current speed and tension are well matched, generates an instruction to maintain the current process, and continues to execute conventional PID control. If the stress risk index is greater than the safety value but less than or equal to the aforementioned dynamic critical value, the system determines that there is a slight risk of residual stress accumulation. However, this risk can be mitigated by reducing the tension, provided it does not fall below the physical lower limit. This is used to eliminate and generate a nonlinear tension reconstruction command. This command calculates the initial strain required to reduce the residual stress to a safe range by inversely solving the Maxwell equations. The specific inverse solution algorithm is as follows:

[0034] in, The safety margin factor is a dimensionless parameter representing the reduction ratio of the target stress relative to the cold flow threshold, preferably 0.1-0.3. This factor is determined based on the statistical distribution characteristics of the material's cold flow threshold: for a specific batch of adhesive, the standard deviation of its cold flow threshold is determined through multiple sets of experiments. ,set up The average value is used to cover 99.7% of the material property fluctuation range; the system will... Substituting the inverse transformation form of the Hooke's law correction algorithm, the nonlinear tension reconstruction command finally sent to the servo drive unit is generated. If the calculated Then it will automatically clamp to And trigger the next level of control logic; If the stress risk index exceeds a critical value, the system determines that even if the tension is reduced to the physical limit... It also fails to meet the quality requirements, namely, that at the current speed, it is impossible to eliminate the risk and generate a speed intervention command through tension adjustment; This instruction does not merely qualitatively reduce speed, but rather calculates the maximum permissible encoder linear velocity that meets quality requirements based on the inverse kinematic parameters derived from the target residual stress. To address the potential mathematical singularities, zero denominators, or loss of physical meaning leading to negative results when directly applying the inverse formula, the system incorporates a pre-judgment logic before execution: calculating the dimensionless stress ratio, with the following formula:

[0035] The system determines if This indicates that even over an infinitely long period, i.e., when the velocity approaches zero, the residual stress in the material cannot be reduced below the target value through relaxation. This is usually because the initial ultimate stress at low temperatures is already below the target, but there is still a risk of cold flow. In this case, the system directly... Force clamping to the minimum permissible creep speed of the equipment, such as 5 m / min, and trigger a process alarm, skipping subsequent logarithmic calculations; only when Only when the logarithmic term is negative and the denominator is not zero will the system execute the following physically valid calculation formula:

[0036] in, Represented by natural constant The natural logarithm function with base 0; For based on The calculated strain value; the coefficient 60 in the formula is used to convert the calculation result into the unit required for PLC servo control instructions, which is m / min; It must be emphasized here that, to ensure the physical boundary conditions for the above reverse solution hold, the speed intervention command is strictly defined as a speed-tension coordinated command: the encoder linear velocity setpoint is smoothly adjusted to an S-shaped ramp. At the same time, the system forcibly clamps the tension setpoint to the aforementioned calculated physical lower limit. This is because The calculation formula is based on That is, corresponding The minimum strain is a prerequisite; if only the velocity is reduced without forcibly reducing the tension, the actual initial strain will be higher than the model's preset value. This results in the final residual stress failing to converge to the target value. This bivariate locking mechanism prevents control failure caused by low speed and high tension, ensuring the logical closed loop of the intervention strategy. Furthermore, due to the formula It is affected by speed The hardening effect, i.e., a decrease in speed causes the material to soften, thereby changing the ultimate strain value, is as described above. The calculations are performed internally by the PLC using a fixed-point iterative method: the system estimates the current speed. Substitute into the formula to calculate the preliminary result. Recalculate using this new speed Updated again This loop typically converges within 3 scan cycles, thus ensuring the physical accuracy of the velocity intervention command; This embodiment constructs a defense system that coordinates tension and speed; it clarifies the dynamic calculation path of critical values ​​and the quantitative calculation method of speed intervention, and solves the mathematical domain defect of the formula by introducing stress ratio prediction logic, ensuring the logical closed loop and executability of the control strategy, and significantly improving the timeliness and stability of the product.

[0037] Example 6: The multidimensional data acquisition module includes: a tension detection unit, which includes pressure sensors installed on both sides of the floating roller for acquiring tension sensor values; An environmental sensing unit includes an infrared temperature sensor pointing towards the surface of the tape for collecting the surface temperature of the adhesive layer. The motion acquisition unit includes an absolute encoder for the servo motor, used to acquire the encoder linear speed and the current roll diameter; This embodiment details the hardware implementation of the multidimensional data acquisition module to ensure data accuracy; the tension detection unit acquires tension sensor values ​​through precision pressure sensors installed on both sides of the floating roller, and the low inertia design of the floating roller ensures sensitive capture of high-frequency tension fluctuations. Meanwhile, the environmental sensing unit uses an infrared temperature sensor pointing towards the surface of the tape to collect the surface temperature of the adhesive layer; the sensor is installed at the coating head outlet or rewinding inlet at a specific distance from the tape surface, preferably set to 15mm to 30mm, in order to balance the field of view coverage and thermal radiation attenuation. To ensure the absolute accuracy of the temperature measurement data, the environmental sensing unit is equipped with emissivity compensation parameters within the PLC that match the processed material. For commonly used pressure-sensitive adhesive materials, the preset value is 0.92-0.95. The system performs the following radiation temperature compensation calculation, and the calculation formula is as follows:

[0038] in, For infrared sensor readings, The ambient temperature at the installation location is collected by an independent contact temperature probe; or a simplified linear compensation algorithm is used to eliminate the influence of reflection interference on the viscosity model input. In addition, the motion acquisition unit acquires the encoder linear speed and current roll diameter in microsecond cycles through the absolute encoder of the servo motor; Regarding the acquisition of the current roll diameter, since the encoder itself can only output rotation angle and angular velocity, the system embeds a roll diameter observation algorithm based on thickness integration within the PLC:

[0039] in, The preset core radius for the PLC For the thickness of the tape in the formula library, This refers to the real-time encoder linear speed; considering the digital processing characteristics of the PLC, the above integral term... This is approximated in the controller by accumulating the number of pulses or by discrete time integration, i.e. ,in The scanning period; or, in a fixed-length winding scenario, a discrete algorithm based on the accumulation of rotations is used, and its calculation formula is:

[0040] in, This refers to the cumulative radian feedback from the encoder; the algorithm logic overcomes the physical limitation that sensors cannot directly measure dynamic roll diameter, ensuring the aforementioned stress model... Reliability of the source of the variable; This embodiment provides a high signal-to-noise ratio physical input for the software algorithm through specific hardware selection; in particular, the emissivity calibration and roll diameter integral reconstruction of infrared thermometry technology solve the problems of inconsistency between ambient temperature and actual material temperature and roll diameter measurement lag, ensuring the authenticity and reliability of the digital twin model.

[0041] Example 7: The adaptive control module also includes a feedback correction unit, which is used to calculate the rate of change of the predicted residual stress value and dynamically adjust the gain parameter of the PID control loop according to the rate of change.

[0042] This embodiment introduces a closed-loop optimization mechanism into adaptive control; the feedback correction unit continuously monitors the rate of change of the predicted residual stress after executing nonlinear tension reconstruction commands or velocity intervention commands; to avoid control oscillations caused by computational noise, this rate of change... The result was obtained after discrete difference and low-pass filtering, and the specific formula is as follows:

[0043] in, This is the original difference value at the current moment. and These are the predicted residual stress values ​​for the current and previous scanning cycles, respectively. The PLC scan cycle, such as 0.01 seconds. The filtering smoothing coefficient is preferably between 0.1 and 0.2, and this coefficient is determined based on the signal-to-noise ratio analysis of the sensor signal: A fast Fourier transform is performed on the original tension signal under steady state to identify the noise frequency band, and a cutoff frequency is set. The formula for calculating the frequency components below the dominant noise frequency is:

[0044] in, The cutoff frequency required to filter out noise; to prevent the filter from outputting incorrect values ​​during the initial power-on phase of the system, the variable... The gain parameters of the PID control loop are explicitly set to zero during system initialization; the gain parameters are dynamically adjusted based on the smoothed rate of change. Specifically, in response to tension system fluctuations caused by the system being in velocity intervention mode, this unit automatically reduces the proportional gain and appropriately increases the differential gain; this dynamic adjustment process follows the following gain scheduling function, the calculation formula of which is:

[0045] in, Based on the basic gain parameter, The time rate of change of the predicted residual stress value obtained above. The preset sensitivity coefficient is defined with dimensions set to the reciprocal of the rate of change of stress; the unit is... The physical meaning of is the response weight of the controller to the rate of change of residual stress. Its value is typically set from 0.1 to 10.0, and the specific value is calibrated based on the mechanical response bandwidth of the servo system. This calibration is achieved through a step disturbance response experiment: injecting stress step signals of different amplitudes into the system and recording the overshoot and settling time of the system response; adjusting... Adjust to minimize overshoot under large disturbances. To minimize the settling time, the optimal balance point is found through iterative optimization. Used to limit gain under high-frequency disturbances This algorithm is used to provide lead compensation during stress abrupt changes. It automatically suppresses proportional action to prevent overshoot when stress changes drastically, while enhancing derivative action to improve response speed. To ensure the absolute stability of the control system and prevent [damage / losses]... Excessive transients caused the calculated gain value to exceed the allowable range of the servo driver, and the system subsequently adjusted the calculated gain. and The calculation formula for implementing saturation limiting is as follows:

[0046]

[0047] in, The values ​​are preset safety boundary values ​​based on motor characteristics; in addition, the feedback correction unit has a loop identification function: when the system is in nonlinear tension reconstruction mode, the gain adjustment is applied to the tension PID loop inside the PLC; when the system is in speed intervention mode, the gain adjustment is applied to the speed loop PID parameters of the servo driver through bus communication to ensure dynamic matching between the controlled object and the intervention strategy. This embodiment solves the transient stability problem in the adaptive adjustment process; through dynamic gain adjustment and safety limiting, it prevents tension oscillation caused by control strategy switching, especially sudden speed reduction, and achieves a smooth process transition, ensuring the consistency of winding quality during the intervention process.

[0048] Example 8: Please see Figure 2 A PLC-based double-sided tape processing method includes the following steps: S1, acquiring the tension sensor value, encoder linear speed, current roll diameter and adhesive surface temperature during the double-sided tape processing process to generate a real-time working condition state vector. S2. Based on the preset viscoelastic model parameters and the tension sensor values ​​in the real-time working condition state vector, calculate the instantaneous tensile strain of the double-sided tape. S3. Based on the physical relaxation time window determined by the encoder linear velocity, simulate the stress attenuation behavior of the tape during transmission and generate a predicted value of residual stress. S4. Compare the predicted residual stress value with the preset glue cold flow threshold to generate a stress risk index. S5. Based on the stress risk index, generate nonlinear tension reconstruction instructions or speed intervention instructions to achieve predictive control of winding quality.

[0049] This embodiment provides a PLC-based double-sided tape processing method, which strictly corresponds to the operating logic of the above system. In step S1, the PLC synchronously acquires tension, speed, roll diameter and adhesive temperature with an extremely short scanning cycle to construct a real-time working condition state vector. In step S2, the system calls the preset rheological parameters and calculates the current instantaneous tensile strain of the tape by combining the real-time tension and speed. In step S3, the system calculates the time window using the ratio of distance to speed, substitutes it into the rheological model to simulate the stress release process of the tape during transmission, and predicts the residual stress value at the winding point. Based on this, step S4 compares the predicted value with the cold flow threshold and outputs a quantified stress risk index. In step S5, the system automatically selects whether to maintain the status quo, reconstruct the tension curve, or force a reduction in speed based on the magnitude of the risk index. This embodiment solidifies complex rheological principles into standard execution steps of a PLC. This method enables equipment to automatically find the optimal balance between capacity and quality, greatly reducing reliance on highly skilled process personnel and realizing the transformation from empiricist production to digital intelligent manufacturing. It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention.

Claims

1. A PLC-based double-sided tape processing system, characterized in that, include: The multi-dimensional data acquisition module is configured to acquire tension sensor values, encoder linear speed, current roll diameter, motor torque, and adhesive surface temperature in real time during the double-sided tape processing process, in order to generate a real-time working condition state vector. The rheological property analysis module is configured to calculate the instantaneous tensile strain of the double-sided tape under the current traction state based on preset viscoelastic model parameters and the tension sensor values ​​in the real-time working condition state vector. The stress relaxation prediction module is configured to calculate the physical relaxation time window based on the encoder linear speed and the preset inter-roller transfer distance, and combine the adhesive layer surface temperature and the instantaneous tensile strain to generate the predicted value of residual stress when reaching the winding position through rheological dynamics calculation. The risk assessment and decision-making module is configured to compare the predicted residual stress value with the preset adhesive cold flow threshold to generate a stress risk index that quantifies the risk of adhesive overflow and deformation within the tape roll. The adaptive control module is configured to generate nonlinear tension reconstruction commands or speed intervention commands based on the stress risk index, and send the commands to the servo drive unit to adjust the machining parameters.

2. The PLC-based double-sided tape processing system according to claim 1, characterized in that, The rheological property analysis module includes: The parameter mapping unit is used to call the elastic modulus and viscosity coefficient that match the current processed material from the PLC formula library as the viscoelastic model parameters; The strain calculation unit is used to calculate the instantaneous tensile strain based on the encoder linear velocity and tension sensor value in the real-time working condition state vector, using a nonlinear Hooke's law correction algorithm.

3. The PLC-based double-sided tape processing system according to claim 1, characterized in that, The stress relaxation prediction module includes: The time-domain conversion unit is used to divide the preset inter-roller transmission distance by the encoder linear velocity in the real-time operating condition state vector to obtain the physical relaxation time window. The dynamic simulation unit is used to input the instantaneous tensile strain, the physical relaxation time window, and the adhesive layer surface temperature into a preset Maxwell or Kelvin-Voigt rheological model to simulate the stress decay process and output the predicted value of the residual stress.

4. The PLC-based double-sided tape processing system according to claim 1, characterized in that, The risk assessment and decision-making module includes: The pressure distribution modeling unit is configured to predict the radial pressure distribution between the winding layers based on the current roll diameter and the predicted residual stress value. The threshold determination unit is configured to determine whether the maximum value of the radial pressure distribution exceeds the glue cold flow threshold, and to calculate the stress risk index based on the amplitude or integral area exceeding the threshold.

5. The PLC-based double-sided tape processing system according to claim 1, characterized in that, The adaptive control module executes the following control logic: If the stress risk index is less than or equal to a preset safety value, an instruction to maintain the current process is generated; If the stress risk index is greater than the safety value and less than or equal to the critical value, the nonlinear tension reconstruction instruction is generated. The nonlinear tension reconstruction instruction is used to generate a variable tension curve based on an equal residual stress target. If the stress risk index is greater than the critical value, the speed intervention command is generated. The speed intervention command is used to reduce the encoder linear speed to extend the physical relaxation time window.

6. The PLC-based double-sided tape processing system according to claim 1, characterized in that, The multidimensional data acquisition module includes: The tension detection unit includes pressure sensors installed on both sides of the floating roller for collecting the tension sensor values. An environmental sensing unit includes an infrared temperature sensor pointing towards the surface of the tape, used to collect the surface temperature of the adhesive layer; The motion acquisition unit includes an absolute encoder for a servo motor, used to acquire the encoder's linear velocity and the current roll diameter.

7. The PLC-based double-sided tape processing system according to claim 1, characterized in that, The adaptive control module also includes: The feedback correction unit is used to calculate the rate of change of the predicted residual stress value and dynamically adjust the gain parameter of the PID control loop according to the rate of change.

8. A PLC-based method for processing double-sided adhesive tape, applied to the PLC-based double-sided adhesive tape processing system described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Obtain the tension sensor value, encoder linear speed, current roll diameter and adhesive surface temperature during the double-sided tape processing to generate a real-time working condition state vector. S2. Based on the preset viscoelastic model parameters and the tension sensor value in the real-time working condition state vector, calculate the instantaneous tensile strain of the double-sided tape. S3. Based on the physical relaxation time window determined by the encoder linear velocity, simulate the stress attenuation behavior of the tape during transmission and generate a residual stress prediction value. S4. Compare the predicted residual stress value with the preset glue cold flow threshold to generate a stress risk index. S5. Based on the stress risk index, generate nonlinear tension reconstruction instructions or speed intervention instructions to achieve predictive control of winding quality.

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