Mirror surface aluminum foil thickness self-adaptive control method for aluminum foil rolling mill

Abstract

The present application belongs to the technical field of aluminum foil rolling control, and particularly relates to a mirror surface aluminum foil thickness self-adaptive control method for an aluminum foil rolling mill, which comprises the following steps: obtaining the initial entry thickness deviation of the mirror surface aluminum foil and the real-time strip surface temperature; obtaining a dynamic variable stiffness index according to the real-time strip surface temperature and a preset basic rolling mill stiffness; obtaining a roll gap adjustment amount containing oil film distortion compensation according to the initial entry thickness deviation, the dynamic variable stiffness index and the real-time rolling line speed; and obtaining a roll gap control value and a tension decoupling compensation instruction value according to the roll gap adjustment amount containing oil film distortion compensation and a preset safe rolling reduction threshold value. The present application introduces dynamic compensation of thermal expansion and oil film bearing effect, and transfers the extreme rolling reduction task to the tension control loop, thereby improving the thickness control precision and avoiding the strip breakage problem.

Description

Technical Field

[0001] This invention relates to the field of aluminum foil rolling control technology. More specifically, this invention relates to an adaptive control method for the thickness of mirror-finish aluminum foil used in aluminum foil rolling mills. Background Technology

[0002] Ultra-thin mirror aluminum foil plays an important role in modern industrial manufacturing, electronic component packaging, and precision material processing. During the continuous reversible rolling process of ultra-thin mirror aluminum foil, uneven thickness and strip breakage often occur due to equipment thermal deformation or drastic fluctuations in operating conditions. Therefore, high-precision and stable thickness and tension control is particularly important for the production of ultra-thin mirror aluminum foil.

[0003] In related technologies, for example, Chinese patent application document with publication number CN120619072A discloses a thickness control method for a single-stand hot roll mill. This method obtains the distance between the hot roll mill and the thickness gauges on the inlet and outlet sides, the stiffness of the mill when rotating forward, and the stiffness of the mill when rotating in reverse. Based on the running speed of the strip under the thickness gauge, it calculates the roll gap feedforward adjustment amount and the roll gap feedback adjustment amount, and combines the two to calculate the final roll gap adjustment amount of the hot roll mill, thereby controlling the hydraulic actuator to adjust the roll gap.

[0004] However, in the rolling of ultra-thin mirror aluminum foil, the work rolls are subjected to intense frictional heat and deformation heat, resulting in uneven thermal expansion and causing a drift in the actual equipment support stiffness. At the same time, during the acceleration and deceleration phases of the mill, the thickness of the oil film at the rolling interface changes abruptly due to the hydrodynamic pressure effect, causing distortion in the actual size of the equivalent roll gap. The aforementioned technologies use a fixed static mill stiffness and do not consider the dynamic changes in the load-bearing capacity of the fluid oil film, leading to inaccurate thickness compensation control under abnormal material thermodynamic conditions and variable speed conditions. Furthermore, mirror aluminum foil in the ultra-thin thickness range has extremely weak tensile strength. If all the thickness adjustment amounts in the relevant technologies are applied to the vertical hydraulic roll gap, it is easy to cause instantaneous local overpressure, which can lead to wrinkling or tearing of the ultra-thin aluminum foil. Summary of the Invention

[0005] To address the technical problems of inaccurate thickness compensation and strip breakage caused by full-gap reduction under complex temperature and speed conditions, this invention provides an adaptive thickness control method for mirror aluminum foil in aluminum foil rolling mills. The method includes: acquiring the initial entry thickness deviation and real-time strip surface temperature of the mirror aluminum foil; calculating the relative change between the real-time strip surface temperature and a preset reference rolling temperature; downwardly correcting a preset basic mill stiffness based on the relative change to obtain a dynamic variable stiffness index; obtaining the stiffness compensation amount using the initial entry thickness deviation, the dynamic variable stiffness index, and a preset aluminum foil plastic deformation coefficient; and obtaining the oil film thickness drift factor based on the real-time rolling line speed and the rated maximum rolling speed to adjust the stiffness compensation. The amount and oil film thickness drift factor are fused to obtain the roll gap adjustment amount including oil film distortion compensation; the overflow ratio of the absolute value of the roll gap adjustment amount exceeding the preset safe reduction threshold is calculated, and the tension sharing weight is obtained based on the overflow ratio; the roll gap control value is determined by combining the roll gap adjustment amount and the tension sharing weight; the adjustment polarity of the roll gap adjustment amount is extracted; the tension decoupling compensation command value is obtained by combining the tension calibration value after the initial steady state of the system, the preset yield tension limit of the aluminum foil material, the adjustment polarity, and the tension sharing weight; the roll gap control value is sent to the hydraulic servo system of the hot rolling mill to adjust the roll gap, and the tension decoupling compensation command value is sent to the coiler drive system to adjust the actual rolling tension.

[0006] This invention corrects the stiffness of the basic rolling mill by incorporating changes in strip surface temperature, thus offsetting the stiffness distortion caused by local thermal expansion of the rolls due to frictional heating during the rolling of ultra-thin mirror aluminum foil. It also introduces a real-time rolling line speed to construct an oil film thickness drift factor, offsetting the equivalent roll gap reduction deviation caused by the rapid thickening of the oil film due to hydrodynamic pressure under acceleration and deceleration conditions. When faced with excessive thickness fluctuations, this invention weakens the vertical roll gap extrusion amplitude based on the overflow ratio of the roll gap adjustment, transferring the excess thickness reduction task to the tension control loop. It uses longitudinal tension stretching instead of simple vertical roll gap extrusion, avoiding the aluminum foil wrinkling or tearing caused by instantaneous local overpressure during full-pressure operation, thereby improving the accuracy of thickness control and the stability of the actual rolling control process.

[0007] Preferably, the tension sharing weight satisfies the following relationship: In the formula, To share the weight of tension, This refers to the roll gap adjustment that includes compensation for oil film distortion. The preset safe pressure threshold, For unit step function, It is the hyperbolic tangent function.

[0008] This invention obtains the relative extent to which the theoretically required thickness correction exceeds the safe plastic boundary of the aluminum foil material by comparing the roll gap adjustment amount, which includes oil film distortion compensation, with a preset safe pressing threshold. When the required thickness correction exceeds the safe pressing threshold, the tension sharing weight is increased to limit excessive adjustment made solely by the hydraulic pressing system. This transforms the risk of aluminum foil breakage caused by excessive single roll gap pressing into a longitudinal tension sharing parameter, thereby providing an accurate data basis for subsequently transferring thickness control to the tension control loop and improving the safety of the ultra-thin aluminum foil thickness adjustment process.

[0009] Preferably, the roll gap control value satisfies the following relationship: In the formula, This is the roll gap control value. To share the weight of tension, This refers to the roll gap adjustment amount that includes oil film distortion compensation.

[0010] This invention utilizes the complement of the weight-sharing as the tolerance coefficient of the pressing actuator. When the system faces a high risk of local overload, which leads to an increase in the tension weight-sharing, the tolerance coefficient decreases accordingly. This weakens the extrusion range of the roll gap adjustment, which includes oil film distortion compensation, in the vertical direction. It avoids the roll gap actuator bearing all the excessive thickness compensation data, protects the hydraulic pressing system from overload impact, and maintains the mill's fine-tuning capability under safe operating conditions.

[0011] Preferably, the tension decoupling compensation command value satisfies the following relationship: In the formula, This is the tension decoupling compensation command value. To share the weight of tension, This refers to the roll gap adjustment that includes compensation for oil film distortion. The initial steady-state tension calibration value was collected during the system power-on initialization phase. For tension conversion equivalent, To extract the sign function of the input value's positive or negative polarity, This is the preset yield tension limit for aluminum foil materials.

[0012] This invention utilizes the positive and negative polarity extraction results to synchronously correspond to the adjustment direction of the roll gap, and combines this with a preset yield tension limit to restrict the upper limit of tensile compensation. When the thickness correction margin waived by the roll gap system is large, the deviation of the tension decoupling compensation command value from the initial steady-state tension calibration value increases accordingly. By using longitudinal tensile plastic deformation to replace vertical extrusion, the metal flow of the aluminum foil per unit time remains stable, achieving the purpose of synergistic correction of thickness deviation while preventing local overpressure tearing of the aluminum foil.

[0013] Preferably, the calculation of the relative change range between the real-time strip surface temperature and the preset reference rolling temperature includes: calculating the absolute value of the difference between the real-time strip surface temperature and the preset reference rolling temperature; and calculating the ratio of the absolute value of the difference to the preset reference rolling temperature to obtain the relative change range.

[0014] Preferably, the dynamic variable stiffness index satisfies the following relationship: In the formula, It is a dynamic variable stiffness index. For the basic rolling mill stiffness, For real-time surface temperature, As the reference rolling temperature, It is an exponential function with the natural constant as its base; The thermal attenuation coefficient, and The dimension of is Celsius.

[0015] This invention introduces the relative temperature change rate of the actual rolling temperature deviating from the ideal reference thermal state into the stiffness correction process. When the strip surface temperature becomes abnormally high due to local heating, the relative temperature change rate increases accordingly, thereby correcting the stiffness of the basic mill downward. This transforms the microscopic thermal expansion phenomenon into a direct stiffness softening parameter, offsetting the offset effect of local expansion caused by uneven heating of the rolls on the actual support stiffness. This avoids the thickness control imbalance caused by the fixed static mill stiffness under sudden temperature changes.

[0016] Preferably, the step of obtaining the stiffness compensation amount by utilizing the initial inlet thickness deviation, the dynamic variable stiffness index, and the preset aluminum foil plastic deformation coefficient includes: calculating the product of the initial inlet thickness deviation and the dynamic variable stiffness index; calculating the sum of the dynamic variable stiffness index and the preset aluminum foil plastic deformation coefficient; and calculating the ratio of the product to the sum to obtain the stiffness compensation amount.

[0017] Preferably, obtaining the initial entry thickness deviation of the mirror aluminum foil includes: obtaining the absolute thickness data output by the X-ray thickness gauge; retrieving the pre-set target rolling thickness; calculating the difference between the absolute thickness data and the target rolling thickness to obtain the initial entry thickness deviation.

[0018] Preferably, the method for obtaining the real-time surface temperature includes: obtaining temperature readings collected by a surface temperature sensor within a continuous preset time period; calculating the average value of the temperature readings within the continuous preset time period, and using the average value as the real-time surface temperature.

[0019] Preferably, the step of sending the roll gap control value to the hydraulic servo system of the hot rolling mill to adjust the roll gap, and sending the tension decoupling compensation command value to the coiler drive system to adjust the actual rolling tension, includes: sending the roll gap control value to the hydraulic servo system of the hot rolling mill; driving the hydraulic cylinder to adjust the roll gap through the hydraulic servo system; sending the tension decoupling compensation command value to the coiler drive system; and controlling the motor torque through the coiler drive system to adjust the actual rolling tension.

[0020] The beneficial effects of this invention are as follows: This invention introduces the phenomenon of thermal expansion of the rolls caused by changes in the surface temperature, as well as the hydrodynamic pressure effect generated during acceleration and deceleration, into the rolling control process simultaneously. When obtaining thickness adjustment parameters, it offsets the mechanical stiffness drift caused by frictional heating and the oil film pad thickness deviation caused by changes in rolling speed, thereby obtaining a roll gap adjustment amount that conforms to the actual dynamic working conditions, reducing the thickness control error under complex speed and temperature conditions, and thus improving the accuracy of aluminum foil thickness.

[0021] When faced with pressing requirements exceeding the safe plasticity boundary of aluminum foil material, this invention utilizes a preset safe pressing threshold to obtain the overflow ratio for thickness correction. Based on the overflow ratio, the vertical roll gap pressing operation is transformed into a coordinated adjustment action of roll gap pressing and longitudinal tension stretching. The vertical extrusion task exceeding the capacity of the equipment and material is assigned to the tension control section, reducing the pressure on the hydraulic servo system from local overload impacts, lowering the risk of aluminum foil wrinkling and tearing caused by instantaneous vertical overpressure, maintaining the stability of metal flow in the rolling process, and thus improving the continuity of the aluminum foil rolling process and the stability of the actual production process. Attached Figure Description

[0022] Figure 1 This is a flowchart illustrating the adaptive control method for mirror aluminum foil thickness in an aluminum foil rolling mill according to the present invention;

[0023] Figure 2 This is a schematic diagram illustrating the comparison of compression amounts in this invention. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0026] This invention discloses an adaptive control method for the thickness of mirror-finish aluminum foil used in aluminum foil rolling mills, with reference to... Figure 1 This includes steps S1 to S4:

[0027] S1. Obtain the initial entry thickness deviation and real-time surface temperature of the mirror aluminum foil.

[0028] It should be noted that the initial thickness distribution of mirror-finish aluminum foil during rolling is not only affected by the reduction amount of the previous pass, but also closely related to the deformation release state of the aluminum foil roll during unrolling. Thickness measurement cannot reflect the residual thermal stress inside the material, leading to inaccurate subsequent stiffness compensation. Therefore, this invention uses strip surface temperature as an auxiliary monitoring feature to reflect the initial thermoplastic state of the aluminum foil material before entering the rolling mill.

[0029] Specifically, the absolute thickness data output by the X-ray thickness gauge is acquired, and the pre-calibrated target rolling thickness is retrieved. The difference between the absolute thickness data and the target rolling thickness is used as the initial entry thickness deviation. Simultaneously, the average value of temperature readings collected by the surface temperature sensor over a continuously preset time period is calculated, and this average value is used as the real-time strip surface temperature. The temperature readings collected by the temperature sensor are in degrees Celsius; therefore, the real-time strip surface temperature is measured in degrees Celsius.

[0030] For example, the target rolling thickness is determined based on the finished product specification requirements for the current pass issued by the production process.

[0031] For example, the empirical range of the continuous preset time period is [200, 500] milliseconds. In this embodiment, the continuous preset time period is 300 milliseconds. The implementer can determine the continuous preset time period according to the actual situation. For example, when there is high-frequency electrical noise in the temperature sensor signal, the parameter can be appropriately increased to enhance the filtering and smoothing effect; when the rolling speed is extremely fast and it is necessary to capture temperature transients, the parameter can be appropriately decreased to reduce the response delay.

[0032] S2. Based on the real-time strip surface temperature and the preset basic mill stiffness, and combined with the influence of temperature gradient on the thermal expansion of the roll, obtain the dynamic variable stiffness index.

[0033] It should be noted that in the reversible rolling process of a single-stand hot platen, conventional methods simply switch the static forward or reverse stiffness based on odd or even passes. However, the frictional heat generated during the rolling of extremely thin mirror-finish aluminum foil causes uneven thermal expansion of the rolls. Even slight thermal expansion can cause a drift in the actual support stiffness, rendering the fixed static mill stiffness inapplicable. Ignoring this thermal expansion phenomenon will lead to inaccurate thickness difference compensation. Therefore, this invention, based on the real-time strip surface temperature and the preset basic mill stiffness, combined with the influence of the temperature gradient on the thermal expansion of the rolls, obtains a dynamic variable stiffness index to eliminate stiffness distortion caused by thermal expansion.

[0034] Specifically, the preset basic mill stiffness and reference rolling temperature are retrieved, the relative temperature change rate is obtained based on the real-time strip surface temperature and reference rolling temperature, and the dynamic variable stiffness index is obtained in combination with the basic mill stiffness.

[0035] For example, the empirical range of the basic mill stiffness is [4000, 6000] kN / mm. In this embodiment, the basic mill stiffness is 5000 kN / mm. The implementer can determine the basic mill stiffness according to the actual situation. For example, when replacing the support roll with a larger diameter, this parameter can be appropriately increased to match the increase in the overall mechanical stiffness of the system; when using old rolls with severe wear, this parameter can be appropriately decreased to adapt to the increase in clearance.

[0036] In this embodiment, the reference rolling temperature is 120 degrees Celsius. The implementer can determine the reference rolling temperature according to the actual situation. For example, when the ambient temperature in the workshop is extremely low in winter, resulting in a low initial roll temperature, the parameter can be appropriately reduced to match the initial temperature state. When multiple batches of high-speed rolling make the system as a whole in a high thermal equilibrium state, the parameter can be appropriately increased to prevent frequent triggering of excessive thermal compensation.

[0037] Specifically, the dynamic variable stiffness index satisfies the following relationship:

[0038] ;

[0039] In the formula, It is a dynamic variable stiffness index. For the basic rolling mill stiffness, For real-time surface temperature, As the reference rolling temperature, It is an exponential function with the natural constant as its base; The thermal attenuation coefficient, The empirical value range is [0.1, 0.5]. In this embodiment... The value is 0.2, which can be determined by the implementers based on the actual situation. For example, when the thermal expansion coefficient of the roll material is high, this parameter can be appropriately increased to enhance the suppression of thermal distortion; when equipped with a high-efficiency cooling spray system, this parameter can be appropriately decreased.

[0040] in, This represents the relative rate of temperature change from the ideal reference thermal state to the actual rolling temperature; the larger this value, the greater the possibility of local expansion caused by uneven heating of the rolls, leading to... The smaller the value, the downward correction to the basic mill stiffness causes the dynamic variable stiffness index to soften and weaken with rapid temperature anomalies; the smaller the value, the more stable the current thermal state, leading to... The dynamic variable stiffness index approaches 1, thus making it close to the stiffness of the basic rolling mill. To maintain the benchmark adjustment capability.

[0041] S3. Based on the initial entry thickness deviation, dynamic variable stiffness index, and real-time rolling line speed, combined with the bearing effect of the rolling oil film, obtain the roll gap adjustment amount including oil film distortion compensation.

[0042] It should be noted that for ultra-thin mirror-finish aluminum foil, the oil film thickness at the rolling interface is positively correlated with the rolling speed. During the acceleration phase, the oil film thickens instantaneously, and the equivalent roll gap actually involved in the pressing shrinks. Feedforward adjustment calculation methods typically only combine strip backslip, roll linear speed, and time to calculate the transmission length, or rely on the distance between the feedforward control detection instrument and the hot roll mill to determine the delay. However, oil film thickness fluctuations that do not consider the hydrodynamic aspect are prone to causing thickness deviations during acceleration and deceleration. Therefore, this invention, based on the initial inlet thickness deviation, dynamic variable stiffness index, and real-time rolling linear speed, combined with the load-bearing effect of the rolling oil film, obtains a roll gap adjustment that includes oil film distortion compensation, producing a synergistic effect of adaptively offsetting hydrodynamic pressure under variable speed conditions.

[0043] Specifically, the real-time rolling line speed output by the speed measuring roll is obtained, and the stiffness compensation amount is calculated using the dynamic variable stiffness index, initial entry thickness deviation, and aluminum foil plastic deformation coefficient. An oil film thickness drift factor is constructed based on the real-time rolling line speed, and the stiffness compensation amount and the oil film thickness drift factor are fused to obtain the roll gap adjustment amount, which includes oil film distortion compensation.

[0044] For example, the empirical range of the plastic deformation coefficient of aluminum foil is [1500, 3500] kN / mm. In this embodiment, the plastic deformation coefficient of aluminum foil is 2200 kN / mm. The implementer can determine the value according to the actual situation. For example, when rolling 8-series hard aluminum foil with complex alloy composition and high deformation resistance, this parameter can be appropriately increased to improve the benchmark compensation range of roll gap adjustment and overcome the strong springback of the material; when rolling 1-series soft pure aluminum foil that has been fully annealed, this parameter can be appropriately reduced to prevent over-compensation from causing rolling breakage or strip breakage.

[0045] For example, the empirical range of the rated maximum rolling speed is [800, 1500] m / min. In this embodiment, the rated maximum rolling speed is 1000 m / min. The implementer can determine the rated maximum rolling speed according to the actual situation. For example, when processing thinner mirror aluminum foil, this parameter can be appropriately reduced to tighten the upper limit of the speed and prevent strip breakage. When processing thicker specifications, this parameter can be appropriately increased to improve the overall production line efficiency.

[0046] Specifically, the roll gap adjustment amount, including oil film distortion compensation, satisfies the following relationship:

[0047] ;

[0048] In the formula, This refers to the roll gap adjustment that includes compensation for oil film distortion. This represents the initial inlet thickness deviation. It is a dynamic variable stiffness index. The plastic deformation coefficient of aluminum foil, This refers to the real-time rolling line speed. The preset rated maximum rolling speed, It is an exponential function with the natural constant as its base. The hydrodynamic sensitivity coefficient is... The empirical value range is [1.5, 4]. In this embodiment... The value is 2.5, which can be determined by the implementers based on the actual situation. For example, when using a mirror-finished work roll with extremely low surface roughness, this parameter can be appropriately increased to match the more severe dynamic pressure changes under an extremely thin oil film; when the work roll surface has micro-textures and strong oil storage capacity, this parameter can be appropriately decreased to smooth out the dynamic pressure feedback curve.

[0049] in, It represents the stiffness compensation amount that combines the elastic deformation capacity of the equipment with the resistance to plastic deformation of the material; The larger the value, the greater the initial inlet thickness deviation or the greater the likelihood that the dynamic variable stiffness index dominates the total stiffness of the system, resulting in a larger reference value for the roll gap adjustment, thereby providing sufficient original feedforward pressing action to eliminate thickness error. The smaller the value, the greater the possibility that the incoming material is uniform or the aluminum foil has an excessively large plastic deformation coefficient, making the material extremely difficult to compress. This results in a smaller baseline value for the roll gap adjustment, which automatically reduces the mechanical reduction amplitude when encountering high deformation resistance conditions to prevent overload damage to the rolling mill equipment.

[0050] This represents the relative proportion of the rolling speed within the overall equipment range. This is the oil film thickness drift factor. A larger factor indicates a higher linear velocity, and a greater likelihood of a rapid increase in oil film thickness due to hydrodynamic effects. Greater than 1, thus affecting An upward amplification correction is performed, allowing the roll gap adjustment to open up additional space to offset the thickened oil film layer. The smaller this factor, the higher the likelihood that the mill is operating at low speed or in a crawling state, resulting in extremely weak oil film bearing capacity. Approaching 1 prevents excessive false compensation in the low-speed domain.

[0051] S4. Based on the roll gap adjustment amount including oil film distortion compensation and the preset safety pressure threshold, combined with the preset yield tension limit of the aluminum foil material, obtain the roll gap control value and tension decoupling compensation command.

[0052] It should be noted that traditional thickness control methods combine feedforward and feedback adjustment amounts based on a specific weighted index, resulting in a final adjustment amount for the roll gap of the hot rolling mill that applies entirely and solely to the single-stand reduction system. However, mirror-finish aluminum foil in the extremely thin thickness range has very low tensile strength. If the entire roll gap adjustment amount is applied to the hydraulic roll gap, it can easily cause instantaneous local overpressure, leading to wrinkling or even tearing and breakage of the sheet. Therefore, this invention smoothly transfers some of the extreme thickness reduction tasks to the tension control loop, allowing the mill to maintain a stable metal flow rate of the aluminum foil per unit time by increasing the back tension while ensuring safety with minimal roll gap fluctuations. This achieves stable thickness accuracy and sheet flatness.

[0053] Specifically, a preset safe reduction threshold is obtained. Based on the absolute value of the roll gap adjustment and the safe reduction threshold, the thickness correction overflow ratio is determined. The tension sharing weight is obtained according to the thickness correction overflow ratio. Combining the roll gap adjustment and the tension sharing weight, the roll gap control value is determined. The tension calibration value after the initial steady state of the system and the preset yield tension limit of the aluminum foil material are retrieved. The adjustment polarity of the roll gap adjustment is extracted. Combining the tension calibration value after the initial steady state, the preset yield tension limit, the adjustment polarity, and the tension sharing weight, the tension decoupling compensation command value is obtained.

[0054] For example, the empirical range of the safe reduction threshold is [0.005, 0.02] mm. In this embodiment, the safe reduction threshold is 0.01 mm. The implementer can determine the safe reduction threshold according to the actual situation. For example, when rolling soft 1-series pure aluminum material, the parameter can be appropriately increased to allow the hydraulic cylinder to perform a larger direct roll gap reduction; when rolling easily brittle 8-series hard alloy aluminum foil, the parameter can be appropriately decreased to trigger the tension control nozzle intervention in advance.

[0055] Specifically, the roll gap control value and the tension decoupling compensation command value satisfy the following relationship:

[0056] ;

[0057] ;

[0058] ;

[0059] In the formula, This is the roll gap control value. This is the tension decoupling compensation command value. To share the weight of tension, This refers to the roll gap adjustment that includes compensation for oil film distortion. The preset safe pressure threshold, It is a unit step function, which takes the value 1 when the input value is greater than 0, and takes the value 0 when the input value is less than or equal to 0; The initial steady-state tension calibration value was collected during the system power-on initialization phase. For tension conversion equivalent, It is the hyperbolic tangent function. To extract the sign function of the input value, it takes the value 1 when the input value is greater than 0, -1 when the input value is less than 0, and 0 when the input value is equal to 0. In this embodiment, the preset yield tensile limit of the aluminum foil material is used. The standard is 25 MPa, which can be determined by the implementers based on the actual situation. When processing soft aluminum foil with extremely high purity and extremely low tensile strength, this parameter must be strictly reduced to prevent the strip from breaking due to uncontrolled tension. When processing hard alloy foil that has undergone work hardening treatment, this parameter can be appropriately increased to give the tension loop a wider range of adjustment permissions.

[0060] in, This represents the relative extent to which the theoretically required thickness correction exceeds the material's safe plastic boundary. The larger this value, the greater the possibility that a single pure roll gap reduction will directly cause the foil to break, making the tension sharing weight closer to 1. This suppresses the roll gap control value and transfers most of the control to the tension decoupling compensation command value, replacing vertical roll gap extrusion with longitudinal tension stretching. The smaller this value, the greater the possibility that the required reduction is within the safe range, resulting in a smaller tension sharing weight. This allows the roll gap unit to bear all the thickness adjustment, thus avoiding excessive intervention in tension under normal fine-tuning conditions and preventing longitudinal deviation instability.

[0061] This represents the tolerance coefficient of the pressing actuator. The smaller the coefficient, the higher the risk of local overload the system faces, causing the roll gap control value to be strongly suppressed downward, thereby forcibly weakening the vertical extrusion amplitude. The larger the coefficient, the more likely it is to be in a normal fine-tuning safety condition, causing the roll gap control value to be almost equal to the roll gap adjustment amount including oil film distortion compensation, thus ensuring that the thickness control accuracy is determined by the hydraulic pressing system.

[0062] This represents the tensile compensation based on material strength. The larger the absolute value, the more thickness correction margin the roll gap system gives up, resulting in a larger deviation of the tension decoupling compensation command value from the initial steady state tension calibration value. Thus, longitudinal tensile plastic deformation is used to replace vertical extrusion to keep the metal flow of aluminum foil stable per unit time. The smaller the absolute value, the less need there is for thickness intervention using tension. This causes the tension decoupling compensation command value to return to the initial steady-state tension calibration value, thus avoiding meaningless tension fluctuations that could cause longitudinal deviation of the strip. By extracting the adjustment polarity through a sign function, it is ensured that when the roll gap adjustment amount, which includes oil film distortion compensation, is positive, the tension decoupling compensation command value can be increased synchronously to thin the strip, achieving a precise and coordinated correction effect.

[0063] For example, Figure 2 The graph shows a comparison of the reduction amount in this invention. As can be seen from the graph, during the extreme adverse conditions of the time step, the reduction amount of the traditional static control strategy oscillates violently and exceeds the safety limit, which can easily cause local overpressure and strip tearing. In contrast, when the calculated reduction amount has the risk of exceeding the limit, the roll gap control value of this invention will trigger the safety limit. At this time, the reduction amount will not only not exceed the safety limit, but will also actively decrease, always strictly kept within the safety range, effectively avoiding the risk of equipment overload and strip breakage caused by hard reduction.

[0064] Furthermore, the roll gap control value is sent to the hydraulic servo system of the hot rolling mill to drive the hydraulic cylinder to adjust the roll gap, and the tension decoupling compensation command value is sent to the coiler drive system to control the motor torque to adjust the actual rolling tension, thereby achieving adaptive control of the aluminum foil thickness.

Claims

1. A method for adaptive control of mirror aluminum foil thickness in aluminum foil rolling mills, characterized in that, include: Obtain the initial inlet thickness deviation and real-time strip surface temperature of the mirror aluminum foil; Calculate the relative change between the real-time strip surface temperature and the preset reference rolling temperature. Based on the relative change, adjust the preset basic mill stiffness downwards to obtain the dynamic variable stiffness index, satisfying the following relationship: , It is a dynamic variable stiffness index. The relative range of change For the basic rolling mill stiffness, For real-time surface temperature, As the reference rolling temperature, It is an exponential function with the natural constant as its base. The thermal attenuation coefficient, and The dimension of is Celsius; The stiffness compensation amount is obtained using the initial inlet thickness deviation, dynamic variable stiffness index, and preset aluminum foil plastic deformation coefficient. The oil film thickness drift factor is obtained based on the real-time rolling line speed and the rated maximum rolling speed. The stiffness compensation amount and the oil film thickness drift factor are then fused to obtain the roll gap adjustment amount, which includes oil film distortion compensation, satisfying the following relationship: , This refers to the roll gap adjustment that includes compensation for oil film distortion. This represents the initial inlet thickness deviation. The plastic deformation coefficient of aluminum foil, For real-time rolling line speed, The preset rated maximum rolling speed, The hydrodynamic sensitivity coefficient is... This is the oil film thickness drift factor; Calculate the overflow ratio of the absolute value of the roll gap adjustment exceeding the preset safety reduction threshold, obtain the tension sharing weight based on the overflow ratio, and satisfy the following relationship: , To share the weight of tension, The preset safe pressure threshold, It is a unit step function. It is the hyperbolic tangent function; By combining the roll gap adjustment amount with the tension sharing weight, the roll gap control value is determined, satisfying the following relationship: , This is the roll gap control value; Adjusting the polarity of the roller gap adjustment amount; Combining the initial steady-state tension calibration value of the system, the preset yield tension limit of the aluminum foil material, the adjustment polarity, and the tension sharing weight, the tension decoupling compensation command value is obtained, satisfying the following relationship: , This is the tension decoupling compensation command value. These are the initial steady-state tension calibration values ​​collected during the system power-on initialization phase. For tension conversion equivalent, To extract the sign function of the input value's positive or negative polarity, This is the preset yield tensile limit for aluminum foil material; The roll gap control value is sent to the hydraulic servo system of the hot roll mill to adjust the roll gap, and the tension decoupling compensation command value is sent to the coiler drive system to adjust the actual rolling tension.

2. The adaptive control method for mirror aluminum foil thickness in an aluminum foil rolling mill according to claim 1, characterized in that, The calculation of the relative change between the real-time strip surface temperature and the preset reference rolling temperature includes: calculating the absolute value of the difference between the real-time strip surface temperature and the preset reference rolling temperature; and calculating the ratio of the absolute value of the difference to the preset reference rolling temperature to obtain the relative change.

3. The adaptive control method for mirror aluminum foil thickness in an aluminum foil rolling mill according to claim 1, characterized in that, The method of obtaining stiffness compensation by utilizing the initial inlet thickness deviation, dynamic variable stiffness index, and preset aluminum foil plastic deformation coefficient includes: calculating the product of the initial inlet thickness deviation and the dynamic variable stiffness index; calculating the sum of the dynamic variable stiffness index and the preset aluminum foil plastic deformation coefficient; and calculating the ratio of the product to the sum to obtain the stiffness compensation amount.

4. The adaptive control method for mirror aluminum foil thickness in an aluminum foil rolling mill according to claim 1, characterized in that, The process of obtaining the initial entry thickness deviation of the mirror aluminum foil includes: obtaining the absolute thickness data output by the X-ray thickness gauge; retrieving the pre-set target rolling thickness; and calculating the difference between the absolute thickness data and the target rolling thickness to obtain the initial entry thickness deviation.

5. The adaptive control method for mirror aluminum foil thickness in an aluminum foil rolling mill according to claim 1, characterized in that, The method for obtaining the real-time surface temperature includes: acquiring temperature readings collected by a surface temperature sensor within a continuous preset time period; calculating the average value of the temperature readings within the continuous preset time period, and using the average value as the real-time surface temperature.

6. The adaptive control method for mirror aluminum foil thickness in an aluminum foil rolling mill according to claim 1, characterized in that, The step of sending the roll gap control value to the hydraulic servo system of the hot rolling mill to adjust the roll gap, and sending the tension decoupling compensation command value to the coiler drive system to adjust the actual rolling tension, includes: sending the roll gap control value to the hydraulic servo system of the hot rolling mill; driving the hydraulic cylinder through the hydraulic servo system to adjust the roll gap; sending the tension decoupling compensation command value to the coiler drive system; and controlling the motor torque through the coiler drive system to adjust the actual rolling tension.

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