Remote cooperative regulation and control method for production line equipment based on digital twinning

Abstract

The invention discloses a remote coordinated regulation and control method for production line equipment based on digital twinning, and relates to the technical field of industrial automation control, and the method comprises the steps: collecting outlet transverse temperature distribution, air knife air supply pressure and production line operation data, and calculating an overturning belt strength index, a wall adhesion deviation amount and a left and right pressure supply asymmetry degree; and solving target frequencies of left and right circulating fans by using a fan similarity law in order to eliminate the pressure supply asymmetry degree, and constructing a convection intensity proxy quantity to carry out cooperative compensation calculation on the strip linear speed, so as to generate a cooperative control instruction containing the fan frequency and the linear speed. The production line operation stability and the product quality can be improved.

Description

Technical Field

[0001] This invention relates to the field of industrial automation control technology, and in particular to a method for remote collaborative control of production line equipment based on digital twins. Background Technology

[0002] Continuous coating and drying production lines are widely used in industrial automation. Their core process involves drying moving strips or films using a multi-zone circulating hot air structure. A typical drying section usually includes key components such as a return air box, honeycomb rectifier plate, circulating fans, and air knife slit nozzles. During transport, the strip undergoes convective heat transfer and mass transfer from the air knife slit nozzle jets to achieve solvent evaporation or moisture evaporation. To ensure production efficiency and product quality, precise control of parameters such as fan frequency, air supply temperature, and strip linear velocity is required during the drying process. This ensures uniform drying across the transverse width of the strip and avoids localized over-drying and cracking, undried adhesion, or streaky defects.

[0003] Existing technologies for remote collaborative control of production line equipment generally rely on zone averages, such as the average temperature of the drying zone, the total fan frequency, or the total return air volume, as the primary basis for balancing. While this control method can maintain relative stability of the overall heat load, it often fails to detect and eliminate abrupt changes in narrow-band convective heat transfer in the transverse direction of the strip caused by wall-adhesion effects or flow field disturbances at the air knife slit nozzles. Because the air curtain may be deflected laterally due to slight pressure asymmetry or differences in duct resistance, the drying intensity in local areas may significantly deviate from the average level. Existing control methods based on zone averages not only fail to accurately identify such local anomalies but are also prone to misjudging operating conditions at the remote end, leading to amplification of transverse unevenness when adjusting the total air volume. Furthermore, existing control methods lack an effective linkage mechanism with the strip linear velocity when adjusting fan frequency to balance the pressure, easily causing unexpected fluctuations in the total convective heat transfer per unit length. This fails to simultaneously suppress transverse drying defects and ensure the coordinated stability of the production cycle. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies, such as the difficulty in perceiving and quantifying the transverse narrow-band heat transfer abrupt changes caused by the air knife wall deviation, which makes it impossible to effectively suppress strip-type uneven drying from the source, and the lack of a coordinated linkage mechanism between fan frequency and strip linear speed during the control process, which easily leads to misadjustment or unstable production cycle. Therefore, this invention proposes a remote collaborative control method for production line equipment based on digital twins.

[0005] To address the problems existing in the prior art, the present invention adopts the following technical solution: A method for remote collaborative control of production line equipment based on digital twins, comprising: Step S1: Collect production line operation data, including temperature distribution data of the outlet transverse infrared temperature array, inlet reference temperature, current pressure value of the left and right air supply branches of the air knife, current operating frequency of the left and right circulating fans, and current linear speed of the strip. Step S2: Based on the temperature distribution data of the outlet transverse infrared temperature array and the inlet reference temperature, calculate the overturning zone strength index and the wall-attached deflection vector, and calculate the left and right pressure asymmetry by combining the current pressure values ​​of the left and right air supply branches of the air knife. Step S3: Calculate the target symmetrical supply pressure value of the left and right air supply branches. Based on the target symmetrical supply pressure value, the current pressure value, and the current operating frequency, solve for the target frequency of the left and right circulating fans. Step S4: Construct the convection intensity proxy quantity, and calculate the compensation for the current linear velocity of the strip based on the convection intensity proxy quantity to obtain the target linear velocity; Step S5: Combine the target frequency and target linear speed of the left and right circulating fans into a coordinated control command and send it to the production line controller for execution.

[0006] Preferably, the operating data collected in step S1 specifically includes: temperature values ​​at multiple discrete locations distributed laterally along the strip provided by the outlet transverse infrared temperature array; inlet reference temperature provided by the inlet temperature sensor; air supply pressure on the left and right sides of the air knife collected by the pressure sensor; operating frequency of the left and right fans fed back by the frequency converter; and current linear speed fed back by the traction system.

[0007] Preferably, the process of calculating the overturning zone strength index and the wall-attachment offset vector in step S2 includes: Subtract the inlet reference temperature from the temperature values ​​at discrete locations to obtain the transverse drying indication sequence; Calculate the arithmetic mean of the transverse drying indicator sequence, and subtract the arithmetic mean from each value in the sequence to obtain the mean-free residual sequence; Perform a second-order difference operation on the mean-removed residual sequence to obtain a transverse second-order difference curvature sequence; The maximum absolute value in the second-order difference curvature sequence is selected, and the maximum absolute value is compared with the mean of the absolute values ​​in the sequence to calculate the overturning zone strength index. The mean-removed residual sequence is subjected to a horizontal position-weighted summation, which is then compared with the sum of the absolute values ​​of the sequence to calculate the wall-attached bias vector.

[0008] Preferably, the step of calculating the left and right pressure supply asymmetry in step S2 includes: Calculate the difference and sum of the air supply pressure on the right and left sides of the air knife, and divide the difference by the sum to obtain the asymmetry of the left and right air supply pressure.

[0009] Preferably, step S2 further includes updating the twin parameters based on the digital twin isomorphic mapping: The ratio of the wall-attached offset vector to the left-right pressure supply asymmetry is used as the linear amplification factor. The ratio of the overturning belt strength index to the square of the left and right pressure asymmetry is used as the second amplification factor. The linear amplification factor and the quadratic amplification factor are written into a digital twin to characterize the current duct structure state.

[0010] Preferably, the step of calculating the target symmetrical supply pressure value in step S3 includes: Calculate the arithmetic mean of the air supply pressure on the left and right sides of the air knife, and use the arithmetic mean as the target symmetrical supply pressure value.

[0011] Preferably, the step of solving for the target frequencies of the left and right circulating fans in step S3 includes: Calculate the ratio of the target symmetrical supply pressure value to the air supply pressure on the left side of the air knife, take the square root of the ratio as the left adjustment coefficient, and obtain the target frequency of the left fan by multiplying the left adjustment coefficient by the operating frequency of the left fan. Calculate the ratio of the target symmetrical supply pressure value to the air supply pressure on the right side of the air knife, take the square root of the ratio as the right-side adjustment coefficient, and obtain the target frequency of the right fan by multiplying the right-side adjustment coefficient by the operating frequency of the right fan.

[0012] Preferably, a convection intensity surrogate quantity is constructed, and the current linear velocity of the strip is compensated based on the convection intensity surrogate quantity to obtain the target linear velocity, including: The convection intensity proxy is the square root of the supply air pressure; Calculate the average of the square root of the air supply pressure on the left side and the square root of the air supply pressure on the right side of the air knife, and use it as the current average convection intensity; Calculate the square root of the target symmetrical pressure value as the target convection intensity; Calculate the ratio of the target convection intensity to the current average convection intensity, and multiply this ratio by the current strip linear velocity to obtain the target linear velocity.

[0013] Preferably, the collaborative control command in step S5 includes the target frequency of the left fan, the target frequency of the right fan, and the target linear speed; after receiving the collaborative control command, the production line controller adjusts the left and right circulating fans to the corresponding target frequencies and adjusts the strip conveying mechanism to the target linear speed.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention constructs a quantitative calculation model that includes the overturning strip strength index, the wall-attachment deflection vector, and the left and right pressure asymmetry by collecting data from the outlet transverse infrared temperature array and the air knife supply pressure. This model transforms the invisible physical phenomena caused by the wall-attachment effect of the air knife slit nozzle into calculable quantitative indicators, enabling precise perception and characterization of abrupt changes in transverse narrow-strip heat transfer. Based on the fan similarity law and the left and right pressure asymmetry, the target frequencies of the left and right circulating fans are calculated, which can actively eliminate the pressure difference between the left and right air supply branches. This suppresses the transverse deflection and overturning of the Coanda wall-attachment air curtain from the source, effectively avoiding the risk of local drying defects caused by relying solely on the average amount of the zone for adjustment, and significantly improving the consistency of transverse drying of the strip and product quality.

[0015] 2. This invention constructs a convective intensity proxy based on the square root of the supply air pressure and establishes a collaborative compensation mechanism between the strip linear velocity and the convective intensity. While adjusting the frequency of the left and right circulating fans to balance the supply pressure, the target linear velocity of the strip is synchronously corrected according to the change ratio of the convective intensity proxy. This collaborative control method ensures that the total amount of convective heat transfer and mass transfer received by the strip per unit length remains relatively constant before and after the control, avoiding the fluctuation of drying energy or the instability of production cycle caused by simply adjusting the fan frequency. It achieves a dual improvement in production line operation stability and drying process accuracy, meeting the needs of continuous coating and drying production lines for efficient collaborative control. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 This is a flowchart illustrating a method for remote collaborative control of production line equipment based on digital twins, as provided in an embodiment of the present invention. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0018] Example: This example provides a method for remote collaborative control of production line equipment based on digital twins. See [link to example]. Figure 1 Specifically, including: Step S1: Collect production line operation data, including temperature distribution data of the outlet transverse infrared temperature array, inlet reference temperature, current pressure value of the left and right air supply branches of the air knife, current operating frequency of the left and right circulating fans, and current linear speed of the strip. In embodiments of this method, the collection of production line operation data includes: Temperature values ​​at multiple discrete locations distributed laterally along the strip, provided by the export transverse infrared temperature array; The inlet reference temperature is provided by the inlet temperature sensor; The air supply pressure on the left and right sides of the air knife are collected by pressure sensors respectively; The operating frequencies of the left and right fans are fed back from the frequency converter; The current linear speed fed back by the traction system; Specifically, the temperature distribution data of the outlet transverse infrared temperature array refers to the set of temperature values ​​at each transverse position obtained by measuring and converting the surface radiation energy of the strip by infrared temperature measuring units arranged along the width direction of the strip at the outlet of the drying section. This data is used to characterize the differences in the degree of heating and drying of the strip at different transverse positions. The inlet reference temperature refers to the representative temperature measurement value of the strip before entering the drying section or near the inlet. This temperature is used to characterize the initial thermal state and thermal load benchmark of the strip when it enters the drying section. The current pressure value of the left and right air supply branches of the air knife refers to the static pressure or total pressure measurement value formed in the corresponding branch when circulating hot air is delivered to the left and right air supply channels of the air knife slit nozzle. The pressure reflects the driving force of the airflow at the nozzle to obtain the jet velocity and affects the impact heat transfer intensity and the tendency of the air curtain to adhere to the strip surface. The current operating frequency of the left and right circulating fans refers to the output frequency or equivalent speed of the frequency converter driving the left and right circulating fans. This frequency determines the fan impeller speed, thereby affecting the circulating air volume and the duct pressure head level, and further affecting the pressure distribution of the left and right air supply branches. The current linear speed of the strip refers to the instantaneous running speed of the strip along the conveying direction of the production line. This speed determines the residence time of the strip in the drying section and the intensity of heat transfer and mass transfer per unit length, thus reflecting the result and stability of the drying process together with the temperature distribution.

[0019] Specifically, during production line operation, an outlet transverse infrared temperature array perpendicular to the strip width direction is arranged at the outlet of the drying section, and the correspondence between the temperature measurement unit channel number and the transverse position coordinate is completed. This ensures that each temperature measurement channel corresponds to a discrete position in the transverse direction of the strip, forming a fixed sequence of temperature sampling points. The correspondence calibration is achieved by dividing the effective width of the strip into equal intervals, with the interval being the equivalent field of view width of a single channel of the infrared array to ensure that adjacent sampling points cover a continuous transverse area without obvious blind spots. The instantaneous temperature of each temperature measurement channel is obtained at a sampling period, and the temperature values ​​of multiple discrete positions distributed along the transverse direction of the strip are output in the order of the channel number. At the same time, an inlet temperature sensor is set at the inlet of the drying section and installed at a fixed position before the strip enters the drying section, so that the temperature measured by the sensor can represent the initial thermal state of the strip when it enters the drying section. The inlet temperature sensor outputs the inlet reference temperature at the same sampling period as the infrared array to correspond with the data of the outlet temperature array within the same sampling period. Pressure sensors are set on the left and right air supply branches of the air knife, and their pressure taps are arranged near the air knife. The straight pipe section of the pressure chamber is positioned to obtain a stable branch air supply pressure. In each sampling cycle, the measured value of the pressure sensor is read, and the air supply pressure on the left and right sides of the air knife is output separately. Then, the operation feedback register is read from the frequency converter via the industrial communication interface. This operation feedback register contains at least the operating frequencies of the left and right fans. The read frequency values ​​are expressed in Hertz and directly reflect the fan speed control level. Simultaneously, the linear speed feedback is read from the traction system. This linear speed feedback is calculated by converting the number of pulses counted by the traction roller encoder within the sampling cycle. The conversion uses the circumference of the traction roller and the number of pulses per encoder revolution to determine a proportional coefficient. The circumference of the traction roller is calculated from the measured value of the traction roller diameter, and the number of pulses per encoder revolution is taken from the encoder nameplate parameters. Thus, the current linear speed is output in each sampling cycle. Finally, in the same sampling cycle, the temperature values ​​at multiple discrete locations distributed laterally along the strip, including the inlet reference temperature, the air supply pressure on the left side of the air knife, the air supply pressure on the right side of the air knife, the operating frequency of the left fan, the operating frequency of the right fan, and the current linear speed, are written into the same operation data record and a time stamp is added for subsequent digital twin calculations and remote collaborative control.

[0020] Step S2: Based on the temperature distribution data of the outlet transverse infrared temperature array and the inlet reference temperature, calculate the overturning zone strength index and the wall-attached deflection vector, and calculate the left and right pressure asymmetry by combining the current pressure values ​​of the left and right air supply branches of the air knife. In an embodiment of the present invention, the overturning zone strength index and the wall-attachment deflection vector are calculated, and the left and right pressure asymmetry is calculated in combination with the current pressure values ​​of the left and right air supply branches of the air knife, including: Subtract the inlet reference temperature from the temperature values ​​at discrete locations to obtain the transverse drying indication sequence; Calculate the arithmetic mean of the transverse drying indicator sequence, and subtract the arithmetic mean from each value in the sequence to obtain the mean-free residual sequence; Perform a second-order difference operation on the mean-removed residual sequence to obtain a transverse second-order difference curvature sequence; The maximum absolute value in the second-order difference curvature sequence is selected, and the maximum absolute value is compared with the mean of the absolute values ​​in the sequence to calculate the overturning zone strength index. Specifically, the transverse drying indicator sequence refers to the sequence obtained by subtracting the inlet reference temperature from the temperature values ​​at each discrete location. It reflects the contribution of the drying section to the temperature rise of the strip at each transverse location and can be used as a characterization of the transverse drying intensity. The transverse second-order difference curvature sequence refers to the sequence composed of the second-order difference results calculated for each transverse location in transverse order. Its value reflects the drastic degree of transverse residual change and corresponds to the abrupt change characteristics of local heat transfer intensity within the narrow band. The overturning band intensity index is a ratio-type index formed by the maximum absolute value and the mean of the absolute values. It is used to quantify the degree of enhancement of transverse narrow band heat transfer abrupt change relative to the overall transverse change level. The larger the index, the more prominent the transverse local abrupt change and the higher the risk of strip-like uneven drying.

[0021] Specifically, within the same sampling period, temperature values ​​at multiple discrete locations distributed laterally along the strip are read from the outlet transverse infrared temperature array, and the inlet reference temperature is read from the inlet temperature sensor. Then, the inlet reference temperature is subtracted from the temperature value at each discrete location to eliminate the influence of the initial thermal state of the incoming material on the transverse results, thus forming a transverse drying indication sequence arranged in transverse order. The arithmetic mean of the transverse drying indication sequence is obtained by summing all values ​​in the sequence and dividing by the number of values. This arithmetic mean characterizes the overall temperature rise level of the strip in the drying section during this sampling period. Further, the arithmetic mean is subtracted from each value in the transverse drying indication sequence to obtain a mean-residual sequence, highlighting the deviation of each transverse location relative to the overall average heating level. After obtaining the mean-residual sequence... After the difference sequence, a second-order difference operation is performed along the adjacent discrete positions in the lateral direction. That is, for the residual value at each intermediate position, the value of the residual to its right is calculated by subtracting twice the intermediate residual value and adding the value of the residual to its left, thereby obtaining the lateral second-order difference curvature sequence. The lateral second-order difference curvature sequence is used to characterize the degree of bending of the lateral residual as the lateral position changes and to highlight the narrow band abrupt change. Then, the absolute value of each value in the lateral second-order difference curvature sequence is taken and its arithmetic mean is calculated to obtain the mean of the absolute values ​​of the sequence. At the same time, the value with the largest amplitude is selected from the absolute value sequence as the maximum absolute value. Then, the maximum absolute value is divided by the mean of the absolute values ​​to complete the scale normalization comparison, thereby calculating the overturning band intensity index. This index can quantify the enhancement degree of the lateral narrow band heat transfer abrupt change relative to the overall lateral change level in a dimensionless manner.

[0022] The mean-removed residual sequence is subjected to a horizontal position-weighted summation, which is then compared with the sum of the absolute values ​​of the sequence to calculate the wall-attached bias vector. Calculate the difference and sum of the air supply pressure on the right and left sides of the air knife, and divide the difference by the sum to obtain the asymmetry of the left and right air supply pressure. Specifically, the wall-attachment offset vector refers to the signed normalized quantity obtained by weighting and summing the mean-reduced residual sequence according to the lateral position of the strip. The lateral position coordinates are used as weights to characterize the offset direction and degree of the residual in the strip width direction. It is normalized by the sum of the absolute values ​​of the mean-reduced residual sequence to eliminate the influence of the overall temperature rise scale on the result. Therefore, the wall-attachment offset vector can reflect the trend that the outlet lateral temperature distribution is higher on the left or right side relative to the average level, and thus characterize the directional influence of the air knife wall-attachment air curtain on the lateral heat transfer distribution of the strip when it deflects laterally. The left and right supply pressure asymmetry refers to the normalized ratio of the difference between the supply air pressure on the right side and the supply air pressure on the left side of the air knife to the sum of the two. This asymmetry characterizes the degree of skewness of the supply pressure distribution of the left and right supply air branches in a dimensionless manner. Its positive or negative value corresponds to the direction of higher supply pressure on the right or left side, and the magnitude of the absolute value corresponds to the relative strength of the left and right supply pressure deviation under the total supply pressure level, thus characterizing the supply pressure imbalance state that may induce the lateral deviation of the Coanda wall-attachment air curtain.

[0023] Specifically, after obtaining the mean-reduced residual sequence, each residual value is assigned its corresponding strip lateral position coordinates, and a weighted summation operation is performed on the mean-reduced residual sequence. This involves multiplying each lateral position coordinate by its corresponding residual value and summing the results to obtain a weighted sum, which characterizes the overall offset direction and degree of residual energy in the strip width direction. Subsequently, the absolute values ​​of each residual value in the mean-reduced residual sequence are taken and summed to obtain the sum of absolute values, which characterizes the overall amplitude level of the lateral deviation in that sampling period. Further, the weighted sum is normalized and compared with the sum of absolute values, i.e., the weighted sum is divided by the... The sum of absolute values ​​yields the wall-attached deflection vector, which is used to represent the direction of deflection with a sign and the degree of deflection with an amplitude, and is unaffected by changes in the overall temperature rise scale. Simultaneously, the air supply pressure on the right and left sides of the air knife is read from pressure sensors located on the left and right air supply branches, and the difference and sum of the two are calculated. The difference is used to represent the direction of deviation of the left and right air supply pressures, and the sum is used to represent the overall level of the current air supply pressure. Then, the difference is divided by the sum to obtain the left and right air supply pressure asymmetry, thereby characterizing the relative skewness of the air supply pressure distribution on the left and right air supply branches in a dimensionless manner and providing quantitative input for subsequent remote coordinated control.

[0024] In embodiments of the present invention, updating the twin parameters based on the digital twin isomorphic mapping includes: The ratio of the wall-attached offset vector to the left-right pressure supply asymmetry is used as the linear amplification factor. The ratio of the overturning belt strength index to the square of the left and right pressure asymmetry is used as the second amplification factor. The linear amplification factor and the quadratic amplification factor are written into a digital twin to characterize the current duct structure state; Specifically, after obtaining the wall-attaching deflection vector and the left-right pressure asymmetry within the same sampling period, the wall-attaching deflection vector is divided by the left-right pressure asymmetry to calculate the linear amplification factor. This linear amplification factor is used to characterize the amplification degree of the left-right pressure distribution skew to the wall-attaching deflection response and to reflect the sensitivity of the air curtain attached to the wall to pressure unevenness. Simultaneously, after obtaining the overturning zone intensity index, the overturning zone intensity index is divided by the square of the left-right pressure asymmetry to calculate the quadratic amplification factor. This quadratic amplification factor is used to characterize the contribution of the left-right pressure distribution skew to the transverse narrow band abrupt change intensity under the nonlinear amplification mechanism. The linear amplification factor and the quadratic amplification factor are written into the duct state parameters of the digital twin as duct state parameters and stored in association with the corresponding sampling period time identifier. This allows the digital twin to characterize the amplification characteristics of the duct structure state formed by the current return air box honeycomb rectifier plate air knife slit nozzle and its air supply branch on the wall-attaching deflection and overturning zone phenomena using the amplification factor.

[0025] Step S3: Calculate the target symmetrical supply pressure value of the left and right air supply branches. Based on the target symmetrical supply pressure value, the current pressure value, and the current operating frequency, solve for the target frequency of the left and right circulating fans. In an embodiment of the present invention, the target symmetrical supply pressure value of the left and right air supply branches is calculated, and the target frequency of the left and right circulating fans is solved based on the target symmetrical supply pressure value, the current pressure value, and the current operating frequency, including: Calculate the arithmetic mean of the air supply pressure on the left and right sides of the air knife, and use the arithmetic mean as the target symmetrical supply pressure value; Calculate the ratio of the target symmetrical supply pressure value to the air supply pressure on the left side of the air knife, take the square root of the ratio as the left adjustment coefficient, and obtain the target frequency of the left fan by multiplying the left adjustment coefficient by the operating frequency of the left fan. Calculate the ratio of the target symmetrical supply pressure value to the air supply pressure on the right side of the air knife, take the square root of the ratio as the right side adjustment coefficient, and obtain the target frequency of the right fan by multiplying the right side adjustment coefficient by the operating frequency of the right fan. Specifically, the target symmetrical supply pressure value refers to the representative supply pressure level obtained by arithmetically averaging the supply pressure on the left and right sides of the air knife. This supply pressure value serves as a symmetrical reference for the left and right air supply branches under the same total supply pressure scale, ensuring that the left and right supply pressures converge to the same level without changing the overall air supply capacity, thereby reducing the induced effect of supply pressure distribution skew on the lateral deflection of the air curtain adhering to the air knife wall. The target frequency of the left fan refers to the target output frequency of the inverter of the left circulating fan, calculated to make the supply pressure on the left side of the air knife approach the target symmetrical supply pressure value. It is based on the fan... The pressure head is approximately proportional to the square of the rotational speed. The current operating frequency on the left side is proportionally converted to achieve symmetrical pressure supply by increasing or decreasing the pressure supply on the left side as required. The target frequency of the right fan refers to the target output frequency of the inverter of the right circulating fan, which is calculated to make the air supply pressure on the right side of the air knife approach the target symmetrical pressure value. It is also proportionally converted to the current operating frequency on the right side based on the approximately proportional relationship between the fan pressure head and the square of the rotational speed, so that the pressure supply on the right side is adjusted to a symmetrical level consistent with the left side, thereby providing an executable fan frequency setting for subsequent remote collaborative control.

[0026] Specifically, the air supply pressure on the left and right sides of the air knife is read from the pressure sensor, and the sum of the two is divided by two to obtain the arithmetic mean. This arithmetic mean is used as the target symmetrical supply pressure value to characterize the symmetrical reference supply pressure that the left and right branches should converge under the current total supply pressure level. After obtaining the target symmetrical supply pressure value, the ratio of the target symmetrical supply pressure value to the air supply pressure on the left side of the air knife is calculated. This ratio is used to characterize the degree of deviation of the left supply pressure from the symmetrical reference supply pressure. Based on the approximate proportionality between the fan head and the square of the rotational speed, the square root of the ratio is taken to obtain the left adjustment coefficient, which enables the left adjustment coefficient to control the pressure. The ratio is converted into a frequency ratio, and then the left adjustment coefficient is multiplied by the left fan operating frequency to obtain the left fan target frequency, so that the supply pressure level corresponding to the left fan target frequency approaches the target symmetrical supply pressure value; similarly, the ratio of the target symmetrical supply pressure value to the air supply pressure on the right side of the air knife is calculated, and the square root of the ratio is taken to obtain the right adjustment coefficient. Then, the right adjustment coefficient is multiplied by the right fan operating frequency to obtain the right fan target frequency, so that the supply pressure level corresponding to the right fan target frequency approaches the target symmetrical supply pressure value and forms a symmetrical supply pressure state with the left side, thereby reducing the impact of left and right supply pressure deviation on the uniformity of transverse drying.

[0027] Step S4: Construct the convection intensity proxy quantity, and calculate the compensation for the current linear velocity of the strip based on the convection intensity proxy quantity to obtain the target linear velocity; In an embodiment of the present invention, a convection intensity proxy is constructed, and compensation calculations are performed on the current linear velocity of the strip based on the convection intensity proxy, including: The convection intensity surcharge is the square root of the supply air pressure; Calculate the average of the square root of the air supply pressure on the left side and the square root of the air supply pressure on the right side of the air knife, and use it as the current average convection intensity; Calculate the square root of the target symmetrical pressure value as the target convection intensity; Calculate the ratio of the target convection intensity to the current average convection intensity, and multiply this ratio by the current strip linear velocity to obtain the target linear velocity; Specifically, the convection intensity proxy is a characterization quantity constructed from the square root of the air knife supply pressure. It originates from the law that the slit jet velocity increases with the increase of the supply pressure, and reflects the main influence of pressure on the jet velocity scale in the form of the square root. Thus, it is used to approximately characterize the strength of the convective heat transfer and mass transfer effect generated by the air knife airflow on the strip surface. The target convection intensity is a characterization quantity obtained by taking the square root of the target symmetrical supply pressure value. It is used to represent the level of convection effect corresponding to the air knife jet velocity scale when the left and right supply pressures are adjusted to the symmetrical reference supply pressure. The target linear velocity is a linear velocity setting value obtained by proportionally converting the current linear velocity of the strip according to the ratio of the target convection intensity to the current average convection intensity. It is used to match the scale of heat and mass transfer per unit length of the strip in the drying section with the strength of the convection effect, so as to maintain the coordinated stability of the production line cycle and the drying process while adjusting the supply pressure distribution.

[0028] Specifically, after acquiring the air supply pressure on the left and right sides of the air knife within the same sampling period, the square roots of the air supply pressure on the left and right sides of the air knife are calculated respectively. The sum of the square roots of the two is then divided by two to obtain the average square root value. This average square root value is used as the current average convection intensity to characterize the representative scale of the jet velocity formed at the air knife slit nozzle under the current supply pressure level. Further, the square root of the target symmetrical supply pressure value is calculated to obtain the target convection intensity, which is used to characterize the representative level of the jet velocity scale when the left and right supply pressures converge to the symmetrical reference supply pressure. Subsequently, the ratio of the target convection intensity to the current average convection intensity is calculated. This ratio is used to characterize the relative adjustment factor of the convection intensity scale. The ratio is then multiplied by the current strip linear velocity to obtain the target linear velocity, thereby allowing the strip linear velocity to be adjusted synchronously with the convection intensity scale. This maintains the overall consistency of the heat and mass transfer per unit length during the supply pressure adjustment process and improves operational stability.

[0029] Step S5: Combine the target frequency and target linear speed of the left and right circulating fans into a coordinated control command and send it to the production line controller for execution; In an embodiment of the present invention, the target frequency and target linear speed of the left and right circulating fans are combined into a coordinated control command, which is then sent to the production line controller for execution, including: The coordinated control commands include the target frequency of the left fan, the target frequency of the right fan, and the target linear velocity; After receiving the coordinated control command, the production line controller adjusts the left and right circulating fans to the corresponding target frequencies and adjusts the strip conveyor mechanism to the target line speed. Specifically, the target frequency of the left fan, the target frequency of the right fan, and the target linear speed are combined to form a coordinated control command, and a corresponding sampling period identifier is added to the coordinated control command to ensure that the command parameters are consistent with the current operating condition data. After receiving the coordinated control command, the production line controller writes the target frequency of the left fan into the frequency setting channel of the left inverter and the target frequency of the right fan into the frequency setting channel of the right inverter through the industrial communication interface, so that the left and right circulating fans are adjusted to the corresponding target frequencies to achieve synchronous adjustment of the left and right air supply capacity. At the same time, the production line controller writes the target linear speed into the linear speed setting channel of the strip conveyor mechanism and updates the speed setting of the traction motor according to the linear speed feedback of the traction system, so that the strip conveyor mechanism is adjusted to the target linear speed, thereby completing the coordinated control of the operating status of the left and right circulating fans and the strip conveying cycle and maintaining the operational stability of the drying process.

[0030] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A digital-twin-based remote collaborative regulation method for production line equipment, characterized in that, Comprising the following steps: Step S1, collecting line operation data, the operation data including temperature distribution data of outlet transverse infrared temperature array, inlet reference temperature, current pressure value of air knife left and right air supply branch, current operation frequency of left and right circulating air fans and current line speed of strip; Step S2, calculating the turnover strip strength index and wall sticking deviation vector according to the temperature distribution data of outlet transverse infrared temperature array and the inlet reference temperature, and calculating the left and right supply pressure asymmetry degree combined with the current pressure value of air knife left and right air supply branch; Step S3, calculating the target symmetric supply pressure value of left and right air supply branch, and solving the target frequency of left and right circulating air fans based on the target symmetric supply pressure value, the current pressure value and the current operation frequency; Step S4, constructing the convection intensity proxy, and compensating and calculating the current line speed of strip based on the convection intensity proxy to obtain the target line speed; Step S5, combining the target frequency of left and right circulating air fans and the target line speed into a coordinated control instruction, and issuing it to the line controller for execution.

2. The production line equipment remote collaborative regulation method based on digital twinning according to claim 1, characterized in that, The operation data collected in step S1 specifically includes: temperature values of multiple discrete positions distributed along the transverse direction of the strip provided by the outlet transverse infrared temperature array; the inlet reference temperature provided by the inlet temperature sensor; the left and right air supply pressures of the air knife respectively collected by the pressure sensor; the left and right fan operation frequencies fed back by the frequency converter; and the current line speed fed back by the traction system.

3. The production line equipment remote collaborative regulation method based on digital twinning according to claim 2, characterized in that, The process of calculating the turnover strip strength index and wall sticking deviation vector in step S2 includes: Subtract the inlet reference temperature from the temperature values of the discrete positions to obtain a transverse drying indication sequence; Calculate the arithmetic mean of the transverse drying indication sequence, and subtract the arithmetic mean from each value in the sequence to obtain a mean residual error sequence; Perform a second-order difference operation on the mean residual error sequence to obtain a transverse second-order difference curvature sequence; Select the maximum absolute value in the transverse second-order difference curvature sequence, compare the maximum absolute value with the mean of the absolute values of the sequence, and calculate the turnover strip strength index; Perform a transverse position weighted summation on the mean residual error sequence, compare it with the sum of the absolute values of the sequence, and calculate the wall sticking deviation vector.

4. The production line equipment remote collaborative regulation method based on digital twinning according to claim 3, characterized in that, The step of calculating the left and right supply pressure asymmetry degree in step S2 includes: Calculate the difference and sum of the right and left air supply pressures of the air knife, and divide the difference by the sum to obtain the left and right supply pressure asymmetry degree.

5. The production line equipment remote collaborative regulation method based on digital twinning according to claim 1, characterized in that, Step S2 further includes the step of updating the twin parameters based on the digital twin isomorphic mapping: The ratio of the wall sticking deviation vector to the left and right supply pressure asymmetry degree is taken as the linear amplification coefficient; The ratio of the turnover strip strength index to the square of the left and right supply pressure asymmetry degree is taken as the quadratic amplification coefficient; The linear amplification coefficient and the quadratic amplification coefficient are written into the digital twin to represent the current air duct structure state.

6. The production line equipment remote collaborative regulation method based on digital twinning according to claim 2, characterized in that, The step of calculating the target symmetric supply pressure value in step S3 includes: Calculate the arithmetic mean of the left and right air supply pressures of the air knife, and take the arithmetic mean as the target symmetric supply pressure value.

7. The production line equipment remote collaborative regulation method based on digital twinning according to claim 6, characterized in that, The step of solving the target frequency of left and right circulating air fans in step S3 includes: The ratio of the target symmetric supply pressure value and the air knife left side air supply pressure is calculated, the square root of the ratio is taken as the left side adjustment coefficient, and the left air knife target frequency is obtained according to the product of the left side adjustment coefficient and the left air knife running frequency; The ratio of the target symmetric supply pressure value and the air knife right side air supply pressure is calculated, the square root of the ratio is taken as the right side adjustment coefficient, and the right air knife target frequency is obtained according to the product of the right side adjustment coefficient and the right air knife running frequency.

8. The production line equipment remote collaborative regulation method based on digital twinning according to claim 7, characterized in that, A convection intensity proxy is constructed, and a target line speed is obtained by compensating and calculating the current line speed of the strip based on the convection intensity proxy, including: The convection intensity proxy is the square root of the air supply pressure; The average value of the square root of the air knife left side air supply pressure and the square root of the air knife right side air supply pressure is calculated as the current average convection intensity; The square root of the target symmetric supply pressure value is calculated as the target convection intensity; The ratio of the target convection intensity and the current average convection intensity is calculated, and the ratio is multiplied by the current line speed of the strip to obtain the target line speed.

9. The production line equipment remote collaborative regulation method based on digital twinning according to claim 8, characterized in that, The cooperative control instruction in step S5 includes the left air knife target frequency, the right air knife target frequency, and the target line speed; after the production line controller receives the cooperative control instruction, the left and right circulating air knives are adjusted to the corresponding target frequencies, and the strip conveying mechanism is adjusted to the target line speed.

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