Method and system for controlling a slitting machine based on magnetic powder tension automatic adjustment

Abstract

The application discloses a slitting machine control method and system based on magnetic powder tension automatic adjustment, relates to the technical field of automatic control systems, and comprises the following steps: collecting excitation voltage, excitation current, coil temperature and slitting machine running state data of a magnetic powder brake, calculating an electromagnetic state feature set of the brake and mapping to obtain a working state index representing a magnetic saturation trend, identifying three types of magnetic working zones according to the working state index, matching corresponding target excitation control parameters, maintaining the magnetic powder brake in an effective magnetic working zone and stably completing the roll material tension regulation. The application solves the technical problem that, during the operation of the slitting machine, the core execution element deviates from the ideal working state due to its own temperature rise, current fluctuation and external mechanical disturbance, the output torque is unstable, and the slitting quality is affected, achieves the real-time optimal matching of the execution element of the slitting machine in the whole process, improves the dynamic response speed and the finished product precision of the equipment, simultaneously suppresses the element heat loss and prolongs the service life.

Description

Technical Field

[0001] This invention relates to the field of automated control system technology, and in particular to a slitting machine control method and system based on automatic adjustment of magnetic powder tension. Background Technology

[0002] Roll slitting is widely used in the film processing industry. The magnetic powder tension control system of the slitting machine directly determines the quality of roll processing, production efficiency, and equipment lifespan. The working state of the magnetic powder brake is the core of tension stability control. Existing magnetic powder tension control systems for slitting machines mostly adopt single tension closed-loop regulation, relying solely on tension feedback to adjust the excitation output, suitable for some production scenarios with stable operating conditions. However, slitting machines are multi-axis linkage semi-open processing equipment. The unwinding, traction, winding, and correction mechanisms are prone to speed differences and axial load disturbances, and the magnetic powder brake windings experience significant temperature rise over long-term operation. Traditional control systems cannot simultaneously integrate magnetic powder electromagnetic parameters and assess magnetic saturation trends based on multi-axis operation disturbances. They use fixed thresholds to divide the working range, making it difficult to accurately identify various operating conditions. The excitation adjustment strategy is singular, easily leading to problems such as large tension fluctuations, roll breakage, and uneven winding. Data judgment is one-sided, and adjustment is lagging, failing to meet the high-precision, adaptive, and continuous production control requirements of slitting machines. Summary of the Invention

[0003] This application provides a slitting machine control method and system based on automatic adjustment of magnetic powder tension, which solves the technical problem that during the operation of the slitting machine, the core actuator deviates from the ideal working state due to its own temperature rise, current fluctuation and external mechanical disturbance, resulting in unstable output torque and affecting the slitting quality.

[0004] The first aspect of this application provides a slitting machine control method based on automatic magnetic powder tension adjustment. The method includes: acquiring excitation voltage, excitation current, coil temperature, and slitting machine operating status data corresponding to a magnetic powder brake, the slitting machine operating status data including the unwinding shaft operating status, the rewinding shaft operating status, the main traction pressure roller operating status, the automatic correction mechanism operating status, and tension data; calculating an electromagnetic state feature set of the magnetic powder brake based on the excitation voltage, excitation current, and coil temperature; analyzing the electromagnetic state feature set and the slitting machine operating status data to map a working state index characterizing the magnetic saturation trend of the magnetic powder brake; identifying the target magnetic working zone of the magnetic powder brake according to the working state index, the target magnetic working zone including an under-excitation working zone, an effective magnetic working zone, and a magnetic saturation working zone; and generating target excitation control parameters for adjusting the magnetic powder brake according to the target magnetic working zone to maintain the magnetic powder brake performing roll tension adjustment within the effective magnetic working zone.

[0005] A second aspect of this application provides a slitting machine control system based on automatic magnetic powder tension adjustment. The system includes: a slitting machine operating status data acquisition module, used to acquire the excitation voltage, excitation current, coil temperature, and slitting machine operating status data corresponding to the magnetic powder brake, including the unwinding shaft operating status, the take-up shaft operating status, the main traction pressure roller operating status, the automatic correction mechanism operating status, and tension data; and a working status index mapping module, used to calculate the electromagnetic state characteristic set of the magnetic powder brake based on the excitation voltage, excitation current, and coil temperature. The electromagnetic state feature set and the slitting machine operating state data are analyzed to map a working state index that characterizes the magnetic saturation trend of the magnetic powder brake. A target magnetic working area identification module is used to identify the target magnetic working area of ​​the magnetic powder brake according to the working state index. The target magnetic working area includes an under-excitation working area, an effective magnetic working area, and a magnetic saturation working area. A roll tension adjustment execution module is used to generate target excitation control parameters for adjusting the magnetic powder brake according to the target magnetic working area, so as to maintain the magnetic powder brake performing roll tension adjustment within the effective magnetic working area.

[0006] One or more technical solutions provided in this application have at least the following technical effects or advantages:

[0007] This application synchronously collects electromagnetic parameters of the magnetic powder braking component and operating data of multiple mechanisms of the slitting machine. Through temperature compensation feature extraction and multi-dimensional disturbance fusion calculation, a quantitative index representing the degree of saturation is obtained. The stable working range of the equipment is dynamically divided and matched with differentiated excitation adjustment. The various execution units of the whole machine are synchronously linked and coordinated to continuously maintain the tension execution component in a stable working range. This makes the tension control more stable and the working condition adaptability stronger throughout the slitting roll processing. It achieves real-time optimal matching of the slitting machine execution components throughout the entire process, improves the dynamic response speed of the equipment and the accuracy of the finished product, and at the same time suppresses the heat loss of the components and extends their service life. Attached Figure Description

[0008] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0009] Figure 1 This is a flowchart illustrating the slitting machine control method based on automatic magnetic powder tension adjustment provided in the embodiments of this application.

[0010] Figure 2This is a normalized performance index fitting curve and a schematic diagram of the effective magnetic working area of ​​the slitting machine control method based on automatic magnetic powder tension adjustment provided in the embodiments of this application.

[0011] Figure 3 This is a schematic diagram of the slitting machine control system based on automatic magnetic powder tension adjustment provided in the embodiments of this application.

[0012] Figure labeling: 1. Slitting machine operating status data acquisition module; 2. Working status index mapping module; 3. Target magnetic working area identification module; 4. Roll material tension adjustment execution module. Detailed Implementation

[0013] This application provides a slitting machine control method and system based on automatic adjustment of magnetic powder tension, which solves the technical problem that during the operation of the slitting machine, the core actuator deviates from the ideal working state due to its own temperature rise, current fluctuation and external mechanical disturbance, resulting in unstable output torque and affecting the slitting quality.

[0014] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0015] It should be noted that the terms "first," "second," etc., in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or server that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or modules not explicitly listed or inherent to such processes, methods, products, or devices.

[0016] Example 1, as Figure 1 As shown, a slitting machine control method based on automatic magnetic powder tension adjustment is provided, wherein the method includes: The excitation voltage, excitation current, coil temperature, and slitting machine operating status data corresponding to the magnetic powder brake are acquired. The slitting machine operating status data includes the unwinding shaft operating status, the winding shaft operating status, the main traction pressure roller operating status, the automatic correction mechanism operating status, and tension data.

[0017] In this embodiment, the magnetic powder brake is an industrial electronically controlled actuator that relies on electromagnetic control to transmit braking torque through magnetic powder. It is installed at the unwinding shaft end of the slitting machine and controls the unwinding resistance of the roll material by adjusting the excitation current to maintain processing tension. The slitting machine is an integrated roll material processing equipment that cuts wide roll materials such as PP film and paper into specified narrow rolls along the longitudinal direction and integrates unwinding, traction, winding, automatic correction, and tension control functions.

[0018] Specifically, using a slitting machine as the application carrier, the slitting machine mainly includes the following controllable execution units working in tandem: an unwinding shaft, for example, using an air-expanding shaft structure, used to carry PP roll material; a main traction pressure roller, used to pull the PP roll material forward along a preset path, its lifting action is controlled by a cylinder, in the raised state the operator can pull the free end of the PP through each roller shaft, in the pressed state the pressure roller presses the PP roll material to perform traction; a slitting blade holder, for example, using a circular blade heated by air slitting method, can longitudinally slit the wide PP roll material into multiple narrow roll materials according to the set slitting width; an automatic correction mechanism, whose sensing probe is aligned with the edge of the PP roll material, used to detect and automatically adjust the lateral position of the roll material edge in real time, the target control error for the winding edge alignment is ±5mm for example; a winding shaft, for example, exemplarily set with 2 shafts, also using an air-expanding shaft structure, used to wind up each narrow roll material after slitting; and a magnetic powder brake, for example installed at the end of the unwinding shaft, used to perform automatic tension adjustment of the PP roll material. The equipment's power supply is an example of three-phase four-wire 380V / 32A, and the maximum designed slitting speed is 30M / Min. The following describes the specific implementation method in detail, based on the above equipment structure and the coordination relationships of each execution unit.

[0019] In actual production, industrial data acquisition components can be used to synchronously acquire various parameters. Specifically: For the excitation voltage and excitation current of the magnetic powder brake, a standard voltage transmitter and a DC current acquisition module can be installed in the excitation drive circuit of the magnetic powder brake. The acquisition module is connected in parallel to the two ends of the excitation output line to pick up the voltage signal and in series to pick up the current signal, thereby completing the real-time acquisition of electrical signals. For the temperature of the magnetic powder brake coil, a surface-mount thermocouple temperature sensor can be installed close to the surface of the magnetic powder brake winding shell. The thermocouple leads are connected to the PLC analog signal acquisition channel to acquire the winding operating temperature rise value in real time. For example, the excitation voltage acquisition value can be set to 24V, the excitation current acquisition value to 0.8A, and the steady-state operating temperature of the coil to 42℃.

[0020] The acquisition of operational status data for each mechanism of the slitting machine is achieved using the equipment's existing sensor components. Incremental encoders are installed at the ends of the unwinding shaft, take-up shaft, and main traction pressure roller. These encoders rotate synchronously with the rollers and output pulse signals. The industrial control equipment reads the pulse count and converts it into the real-time linear speed value of each roller, thus characterizing the three-axis operating status. For example, the unwinding linear speed can be set to 20 m / min, the take-up linear speed to 19.8 m / min, and the main traction axis speed to 20 m / min. These speed values ​​are lower than the equipment's maximum designed slitting speed of 30 m / min, and the actual operating speed can be steplessly adjusted by the operator using a speed handle.

[0021] The automatic web-correcting mechanism is equipped with a displacement sensing module. The sensor probe is aligned with the edge of the PP roll material, meaning the edge of the PP roll is in the center of the sensor. During operation, the device continuously outputs the lateral offset of the PP roll material, the start / stop frequency of the web-correcting motor, and the drive power value, thus comprehensively characterizing the real-time operating status of the web-correcting mechanism. For example, the single web-correcting displacement can be set to 3mm, the web-correcting execution frequency to 2 times / minute, and the web-correcting control target is to control the lateral offset of the PP roll material within ±5mm.

[0022] The tension of the PP roll is collected in real time by a film pressure and tension sensor installed below the traction roller assembly. The sensor is in contact with the lower surface of the PP roll and outputs the corresponding real-time tension value. For example, the real-time PP roll tension can be set to 10N, and the preset target tension can be set to 12N. For PP rolls of different thicknesses, with an example thickness range of 0.04-0.30mm, the target tension value can be adjusted according to the actual thickness within the range of 8-20N. The greater the thickness, the higher the target tension value. This adjustment relationship is preset by the operator in the equipment parameter setting form based on the material characteristics.

[0023] The entire acquisition process described above relies on the PLC's built-in synchronous sampling timer for unified management. A unified sampling period is set in advance, for example, a sampling period of 100 milliseconds. All analog signal acquisition channels and pulse counting channels complete signal reading synchronously at the same timing node. This eliminates the timing deviation between analog signals such as voltage and temperature and encoder pulse signals and correction displacement signals, ensuring that all acquired parameters correspond to each other at the same time and avoiding subsequent calculation distortions caused by asynchronous sampling.

[0024] All raw signals collected by sensors are uniformly sent to the digital filtering module built into the PLC software program layer. The moving average filtering operation relies on the PLC program to execute cyclically. The moving average filtering method is used to preprocess the raw signals. After continuously reading five sets of the same type of collected values, the average value is taken as the valid collected data. This filters out electromagnetic noise interference from equipment such as workshop motors and hot air knives, ensuring that the output data is stable and without abnormal jumps.

[0025] Furthermore, the system incorporates built-in logic for judging excessive data collection, and presets normal value ranges for various collection parameters. When a value obtained from a single collection exceeds the preset range, it is directly judged as abnormal data and discarded, and will not participate in subsequent filtering operations. At the same time, the abnormality mark is recorded and stored in the cache to prevent invalid data caused by faults such as sensor disconnection or PP roll material breakage from flowing into the backend calculation process.

[0026] The equipment distinguishes between standby and production data acquisition modes. When the equipment enters standby mode after power-on self-test, the system acquires basic parameters at a low frequency cycle, which is only used for equipment status inspection. When the operator starts the slitting production program, the system automatically switches to the preset high-frequency synchronous sampling mode to continuously acquire all parameters. After the PP roll slitting is completed and the machine stops, the system automatically reduces the sampling frequency to reduce the system's computing power consumption.

[0027] Afterwards, the valid acquired data, after filtering and anomaly removal, is uniformly stored in the PLC's built-in circular buffer. This buffer uses a time-series array format to store all parameters of each synchronously acquired set. The circular buffer follows a first-in, first-out (FIFO) rule; when the buffer storage space is full, it automatically overwrites the oldest stored time-series data, ensuring that the buffer capacity does not overflow. Subsequent electromagnetic characteristic calculation and load disturbance calculation modules can directly retrieve the complete set of acquired data at the corresponding time according to the time-series index, realizing data interoperability between the preceding and following calculation processes.

[0028] After the equipment powers on, completes the connection of water, electricity, and gas pipelines, and initiates its self-test program, the industrial control system triggers all data acquisition components to operate synchronously. Various sensors and acquisition modules, following the aforementioned synchronized sampling, signal filtering, abnormal data removal, condition-specific acquisition, and ring buffer management logic, output processed valid data to the buffer area, completing the synchronous aggregation and storage of excitation-related parameters and the operating status data of multiple mechanisms within the entire machine. The entire data acquisition process is automated, relying solely on the equipment's built-in sensing hardware.

[0029] By synchronously collecting electromagnetic parameters of the brake and operating data of all related mechanisms of the whole machine, and with the supporting collection methods of synchronous sampling, software-level moving average filtering, out-of-limit anomaly rejection, case-by-case collection, and first-in-first-out ring buffer management, the internal and external disturbance factors affecting the working state of magnetic powder are fully covered, providing a real-time data foundation with unified timing, low noise, and no invalid outliers for subsequent accurate determination of magnetic saturation trend.

[0030] The electromagnetic state characteristic set of the magnetic powder brake is calculated based on the excitation voltage, excitation current, and coil temperature. The electromagnetic state characteristic set and the slitting machine operating status data are analyzed to obtain a working state index that characterizes the magnetic saturation trend of the magnetic powder brake.

[0031] Optionally, based on the collected excitation voltage, excitation current and coil temperature, the equivalent inductance characteristics are obtained by correcting the initial inductance through temperature compensation, the impedance phase characteristics are obtained by extracting the phase difference of AC ripple of voltage and current, and the excitation efficiency characteristics are obtained by calculating the power difference based on the winding resistance after compensation and the input power. These are used to form the electromagnetic state characteristic set of the magnetic powder brake. The specific implementation process of this step will be described in detail later.

[0032] Next, the magnetic permeability change capability, unit excitation torque contribution value, and magnetic flux stability are calculated from the three types of electromagnetic characteristics. Then, the roll material load disturbance degree is calculated by combining the slitting machine operation data. The four indicators are fused and mapped by polynomial to obtain the working state index characterizing the magnetic saturation trend of the magnetic powder brake. The specific implementation process of this step will also be described in detail later.

[0033] The target magnetic working zone of the magnetic powder brake is identified according to the working state index. The target magnetic working zone includes an underexcited working zone, an effective magnetic working zone, and a magnetic saturation working zone.

[0034] In this embodiment, the under-excitation operating region is the operating range where the excitation input is insufficient, the magnetic powder braking torque output is low, and the coil tension control capability is insufficient. The effective magnetic operating region is the operating range where the excitation matching is optimal, the torque output is linear and stable, and the coil tension adjustment accuracy and response speed are both excellent. The magnetic saturation operating region is the operating range where the excitation is excessive, the magnetic core magnetization reaches its upper limit, and increasing the excitation is difficult to significantly increase the braking torque, and the tension adjustment sensitivity drops significantly.

[0035] In one embodiment of this application, the scheme constructs a low saturation threshold and a high saturation threshold based on the excitation voltage, excitation current and coil temperature of the magnetic powder brake. Then, based on the relationship between the working state index and the two thresholds, it determines whether the device is in one of three target magnetic working regions: under-excitation working region, effective magnetic working region or magnetic saturation working region. The specific implementation process of this step will be described in detail later.

[0036] Target excitation control parameters are generated according to the target magnetic working area to adjust the magnetic powder brake, so as to maintain the magnetic powder brake performing roll tension adjustment within the effective magnetic working area.

[0037] Specifically, the target excitation control parameters of the magnetic powder brake are generated by three logics based on the target magnetic working zone. The parameters for the underexcitation and magnetic saturation zones are calculated based on the deviation of the corresponding threshold and working state index, respectively. The parameters for the effective magnetic working zone are finely adjusted based on the range. In this way, the magnetic powder brake is stably maintained in the effective magnetic working zone to complete the roll tension adjustment. The specific implementation process of this step will also be described in detail later.

[0038] Furthermore, the method provided in this application embodiment includes: The electromagnetic state characteristic set of the magnetic powder brake is calculated based on the excitation voltage, excitation current, and coil temperature. This electromagnetic state characteristic set includes at least equivalent inductance characteristics, impedance phase characteristics, and excitation efficiency characteristics. Specifically, the initial inductance characteristic is calculated based on the dynamic differential ratio of the excitation voltage and excitation current. Temperature compensation is performed on the winding resistance of the magnetic powder brake using the coil temperature. The initial inductance characteristic is then corrected based on the compensated winding resistance to obtain the equivalent inductance characteristic. The impedance phase characteristic is obtained by extracting the phase difference between the AC ripple signals of the excitation voltage and the excitation current. The heat loss power is calculated based on the compensated winding resistance. The input power is calculated based on the excitation voltage and excitation current. The excitation efficiency characteristic is obtained based on the power difference between the heat loss power and the input power.

[0039] Specifically, the excitation voltage, excitation current, and coil temperature data are first retrieved synchronously from the ring buffer, and the initial inductance characteristics are calculated according to the sampling sequence. The calculation adopts a differential approximation operation method. Two adjacent sets of sampled data are selected, and the instantaneous rate of change of the excitation current is calculated with the sampling period as the time interval. The ratio of the current excitation voltage value to the instantaneous rate of change of the current is taken as the instantaneous inductance value at the corresponding moment. After calculating five sets of instantaneous inductances consecutively, the arithmetic mean is taken to obtain the initial inductance characteristic value.

[0040] Next, temperature compensation calculations are performed on the winding resistance based on the coil temperature. Specifically, the reference resistance is the nominal winding resistance value of the magnetic powder brake. Considering that the operating environment of the slitting machine is typically maintained in the range of 22~26℃, within which the coil temperature rise characteristics have good linearity, 25℃ is used as the reference temperature. The standard temperature coefficient of copper winding, 0.00393 / ℃, is substituted into the temperature compensation formula to calculate the actual winding resistance value at the current temperature. When correcting the initial inductance, the impedance voltage drop component corresponding to the compensated winding resistance is first subtracted from the excitation voltage to obtain the effective voltage corresponding to the pure inductance component. Then, the effective voltage is combined with the instantaneous rate of change of current to recalculate the inductance value, eliminating the inductance calculation deviation caused by the winding resistance, and finally obtaining the equivalent inductance characteristics.

[0041] Next, when extracting the impedance phase characteristics, the original excitation voltage and excitation current signals are first bandpass filtered. The switching frequency range of the bandpass filter adapted to the PWM excitation drive is set to 1kHz to 5kHz to filter out DC components and high-frequency noise in the industrial environment, such as broadband electromagnetic interference generated by the main motor and hot air knife during the operation of the slitting machine, effectively separating the AC ripple signal inherent in the excitation drive. Subsequently, the zero-crossing detection method is used to record the positive zero-crossing points of the voltage ripple and current ripple, and the time difference between the two sets of zero-crossing points is calculated. The ratio of the time difference to the ripple signal period is converted into a phase angle to obtain the impedance phase characteristic value.

[0042] Subsequently, when calculating the excitation efficiency characteristics, the total input power is first obtained by multiplying the excitation voltage by the excitation current. Then, the winding heat loss power is obtained by multiplying the compensated winding resistance by the square of the excitation current. The effective power value is obtained by subtracting the heat loss power from the total input power. The ratio of the effective power to the total input power is used as the excitation efficiency characteristic, which directly reflects the effective proportion of electrical energy converted into magnetic braking torque.

[0043] Finally, the above three types of electromagnetic characteristics are combined to form the electromagnetic state characteristic set of the magnetic powder brake.

[0044] By introducing winding temperature compensation to correct inductance calculation errors, separating fixed-frequency band ripple to extract phase characteristics, and quantifying power loss to calculate conversion efficiency, multi-dimensional and accurate quantification of the internal electromagnetic operating state of the magnetic powder brake is achieved. The accurate extraction of these three types of features is particularly important for slitting machines to maintain tension stability and avoid tension runaway due to magnetic saturation under commonly used slitting speed ranges and continuous long-term operation conditions, providing reliable feature data support for subsequent magnetic saturation trend assessment.

[0045] Furthermore, the method provided in this application embodiment includes: Based on the equivalent inductance characteristics, impedance phase characteristics, and excitation efficiency characteristics, the magnetic permeability variation capability, unit excitation torque contribution value, and flux linkage stability, which characterize the magnetic saturation trend of the magnetic powder brake, are calculated respectively. The roll material load disturbance degree is calculated based on the slitting machine operating status data. The magnetic permeability variation capability, unit excitation torque contribution value, flux linkage stability degree, and roll material load disturbance degree are subjected to polynomial fusion mapping to generate the working status index.

[0046] Optionally, the equivalent inductance characteristics, impedance phase characteristics, and excitation efficiency characteristics obtained from the aforementioned steps can be retrieved to calculate the three saturation characterization indicators: permeability variation capability, unit excitation torque contribution value, and flux linkage stability. The permeability variation capability is calculated using a proportional mapping method, by comparing the real-time equivalent inductance value with the reference inductance value under rated operating conditions of the magnetic powder brake; the ratio result is the permeability variation capability.

[0047] The unit excitation torque contribution value is calculated based on the excitation efficiency characteristics. The rated torque coefficient is the factory nominal parameter of the magnetic powder brake. For example, it is set to 20 Nm of rated output torque per ampere of excitation current. The effective output torque corresponding to the unit excitation current is used as the calculation target. First, the excitation efficiency characteristics are multiplied by the current excitation current value, and then the rated torque coefficient is combined to make a conversion to obtain the real-time unit current torque output capability.

[0048] The flux linkage stability is calculated based on the impedance phase characteristics. The difference between the reference phase angle under no-load conditions and the limiting phase angle under saturation limiting conditions is taken as the maximum phase change range under all conditions. The flux linkage stability is obtained by dividing the difference between the current impedance phase angle and the reference phase angle by the maximum phase change range.

[0049] Next, the degree of roll material load disturbance is calculated based on the slitting machine operating status data. The specific calculation process will be described in detail in the corresponding embodiments later.

[0050] Finally, a polynomial fusion mapping is performed on the magnetic permeability variation capability, unit excitation torque contribution value, magnetic flux stability, and coil load disturbance degree. A weighted polynomial calculation method is adopted, and a corresponding weight coefficient is pre-configured for each index. For example, the weight coefficient of magnetic permeability variation capability is set to 0.3, the weight coefficient of unit excitation torque contribution value is 0.3, the weight coefficient of magnetic flux stability is 0.2, and the weight coefficient of coil load disturbance degree is 0.2. The values ​​of each index are multiplied by their corresponding weights and summed. Then, they are substituted into a first-order linear polynomial for normalization mapping, and finally, a working state index with a value range between 0 and 1 is generated. The index value is used to characterize the magnetic saturation trend of the magnetic powder brake.

[0051] Furthermore, for the example design speed range of the slitting machine covering a maximum speed of 30 m / min, and for different PP roll thicknesses ranging from 0.04 to 0.30 mm, the aforementioned weighting coefficients can be calibrated and adjusted through the equipment parameter setting form. The basis for adjusting the weighting coefficients is: to maximize the correlation between the working state index output and the measured value of tension fluctuation, the optimal weighting combination is determined by experimental calibration.

[0052] By converting three types of electromagnetic characteristics into saturation characterization indicators and integrating load disturbance factors to generate a unified working state index, a quantitative assessment of the magnetic saturation trend of the magnetic powder brake is achieved, providing a real-time quantitative basis for monitoring the magnetic saturation trend of the equipment in continuous slitting operations.

[0053] Furthermore, the method provided in this application embodiment includes: The multi-axis speed difference fluctuation value is calculated based on the unwinding line speed, the winding line speed, and the main axis speed of the main traction pressure roller during operation. The speed difference disturbance component is obtained based on this fluctuation value. The axial resistance torque change is calculated based on the correction execution frequency, correction displacement, and correction drive power during operation of the automatic correction mechanism. The correction disturbance component is obtained based on this change in axial resistance torque. The tension error component between the tension data and the preset target tension data is acquired. The speed difference disturbance component, the correction disturbance component, and the tension error component are linearly normalized to obtain the degree of roll material load disturbance.

[0054] Specifically, firstly, the unwinding speed, winding speed, and main axis speed corresponding to the main traction pressure roller in the slitting machine's operating status data are retrieved, and the multi-axis speed difference fluctuation value is calculated. For example, for a 2-axis winding configuration, the linear speeds of the two winding shafts are calculated separately, and the difference is calculated between each linear speed and the main axis speed. The sum of the absolute values ​​of these differences is taken as the multi-axis speed difference fluctuation value. Then, the ratio of the fluctuation value to the rated linear speed of the equipment is taken as the speed difference disturbance component.

[0055] Next, the web guiding mechanism's operating frequency, displacement, and drive power are retrieved to calculate the change in axial resistance torque. The web guiding control objective is to control the lateral offset of the roll material within ±5mm. The displacement is collected based on this. For the example PP roll material with a thickness of 0.04-0.30mm, the axial friction coefficient is taken as an example of 0.15, and the reference friction resistance torque is... Determined in advance in the following manner: ,in, The rated operating tension of the roll material is in Newtons (N), with an example value of 12 N; r is the contact radius between the roll material and the guide roller at the mounting point of the web guiding sensor, in meters (0.05 m), with an example value of 0.05 m. The product of r and the reference frictional resistance torque is used as the reference frictional resistance torque. The ratio of the real-time correction displacement to the lateral offset reference value is used as the displacement influence coefficient. The displacement influence coefficient, the axial friction coefficient, and the reference frictional resistance torque are multiplied to calculate the change in axial resistance torque generated by a single correction action. Corresponding correction weights are then assigned to the correction execution frequency and correction drive power, respectively. The change in axial resistance torque is then multiplied by the frequency correction coefficient and the power correction coefficient in sequence to complete the weighted correction, resulting in the real-time axial resistance torque fluctuation amplitude per unit time (exemplarily 1 second). The ratio of the fluctuation amplitude to the rated braking torque of the magnetic powder brake is used as the correction disturbance component to quantify the impact of the correction action on the load of the magnetic powder brake.

[0056] Then, the real-time collected tension data is retrieved and the difference is calculated with the preset target tension value. The ratio of the absolute value of the difference to the target tension is taken as the tension error component, which directly reflects the load disturbance level corresponding to the current tension control deviation.

[0057] Finally, the speed difference disturbance component, the correction disturbance component, and the tension error component are linearly normalized. The normalized reference values ​​for the three types of disturbance components all correspond to the maximum disturbance amplitude under the rated operating conditions of the equipment. For example, the speed difference disturbance reference value is set to 5% of the rated linear speed of the equipment, the correction disturbance reference value is set to 8% of the rated braking torque of the magnetic powder brake, and the tension error reference value is set to 10% of the preset target tension. The actual value of each component is divided by the corresponding reference value to uniformly map it to the dimension range of 0 to 1. The arithmetic mean of the three normalized values ​​is taken to obtain the final roll material load disturbance degree. The weight coefficient of each component can be calibrated and adjusted according to the roll material and processing speed. The adjustment method is to preset the corresponding weight value in the equipment parameter setting form.

[0058] By breaking down the sources of load disturbance from three dimensions—multi-axis speed difference, correction action, and tension deviation—and performing unified quantitative processing, the degree of interference of external load on the magnetic powder braking effect is accurately quantified, providing accurate external disturbance reference data for saturation trend assessment.

[0059] Furthermore, the method provided in this application embodiment includes: By inputting the excitation voltage, excitation current, and coil temperature corresponding to the magnetic powder brake, a low saturation threshold and a high saturation threshold are constructed. If the operating state index is less than the low saturation threshold, the target magnetic operating region is determined to be an under-excited operating region. If the operating state index is greater than or equal to the low saturation threshold and less than or equal to the high saturation threshold, the target magnetic operating region is determined to be an effective magnetic operating region. If the operating state index is greater than the high saturation threshold, the target magnetic operating region is determined to be a magnetically saturated operating region.

[0060] Specifically, the working state index generated in real time is retrieved first, and low saturation threshold and high saturation threshold are constructed based on the excitation voltage, excitation current and coil temperature corresponding to the magnetic powder brake. The specific construction process will be described in detail in the subsequent embodiments.

[0061] For example, the low saturation threshold can be set to 0.35, and the high saturation threshold can be set to 0.75. The actual values ​​are determined through calibration based on the magnetic powder brake model and the roll material. The interval determination logic is synchronized with the data sampling cycle. After each set of working status index calculations and updates is completed, a comparison and determination of the target magnetic working area is performed. At the same time, an interval switching anti-jitter mechanism is set. The status flag of the current target magnetic working area is only updated when three consecutive sampling determination results fall into the same interval, avoiding interval misjudgment caused by instantaneous data fluctuations. This anti-jitter mechanism is an optional configuration and can be enabled or disabled according to the equipment control accuracy requirements.

[0062] Next, the real-time operating status index is compared with the low saturation threshold and the high saturation threshold one by one to determine the target magnetic operating zone. When the operating status index is less than the low saturation threshold, the target magnetic operating zone is determined to be an under-excited operating zone. In this zone, the excitation input is insufficient, the magnetic powder braking torque output does not reach the rated range, and the coil tension maintenance capability is weak. When the operating status index is greater than or equal to the low saturation threshold and less than or equal to the high saturation threshold, the target magnetic operating zone is determined to be an effective magnetic operating zone. In this zone, the magnetic powder braking torque shows obvious linear variation with the excitation input, the flux linkage is stable, and the tension adjustment response accuracy is high. When the operating status index is greater than the high saturation threshold, the target magnetic operating zone is determined to be a magnetically saturated operating zone. In this zone, the magnetization degree of the magnetic core is close to the upper limit, and further increasing the excitation input can only bring a very small increase in torque, and the tension adjustment sensitivity drops significantly.

[0063] By classifying and determining the working range in the three-level steps described above, the magnetic saturation state of the magnetic powder brake can be accurately and stably identified in different zones, providing a clear basis for determining the range for subsequent matching of differentiated tension adjustment strategies.

[0064] Furthermore, the method provided in this application embodiment includes: A magnetic state parameter space is constructed based on the excitation voltage, excitation current, and coil temperature. Within the magnetic state parameter space, the unit excitation output torque, flux stability, and tension fluctuation are obtained for different excitation states, and corresponding torque performance curves, flux stability curves, and tension fluctuation curves are constructed respectively. The intersection and coincidence boundary of the torque performance curve, flux stability curve, and tension fluctuation curve are extracted, and the lower boundary of the intersection and coincidence boundary is determined as the low saturation threshold, and the upper boundary is determined as the high saturation threshold.

[0065] Specifically, the core objective of threshold construction is to ensure that the magnetic powder brake always operates within the working window that maximizes the effective torque output per unit excitation current, optimizes magnetic flux stability, and minimizes tension fluctuations. The magnetic state parameter space is constructed during the equipment's factory calibration phase. This is achieved by adjusting the excitation voltage, excitation current, and coil temperature parameters point-by-point on a calibration bench, collecting multiple sets of steady-state operating data covering the entire operating range. Each set of parameters corresponds to a set of performance index values, forming a three-dimensional parameter mapping dataset, thus constructing a complete magnetic state parameter space. This parameter space covers the entire operating range from no-load excitation to full-load braking, from ambient temperature (example 22~26℃) to the coil's steady-state operating temperature, and also covers the range of roll thickness specifications designed and processed by the slitting machine (example 0.04-0.30mm) and the commonly used slitting speed range. Each set of parameters corresponds to a defined magnetic powder operating state. The normalized reference values, including the speed difference disturbance reference value, the correction disturbance reference value, and the tension error reference value, are all determined synchronously in the same calibration stage in the above magnetic state parameter space. The sampling period of 100 milliseconds is also used as the signal acquisition time interval for this calibration stage.

[0066] Within the magnetic state parameter space, for each set of excitation parameters, the unit excitation output torque, flux linkage stability, and tension fluctuation are calculated under the corresponding excitation state. The specific steps are as follows: The unit excitation output torque is the ratio of the current effective output torque to the current excitation current, directly reflecting the torque production efficiency per unit current; the flux linkage stability is calculated based on the impedance phase characteristics, with a higher value indicating stronger flux linkage anti-disturbance capability; the tension fluctuation is the standard deviation of tension data over a fixed time period. For example, the statistical time period is set to 10 seconds, covering tension changes over multiple cycles of roll material operation; a smaller value indicates more stable tension control. Table 1 shows the calibration data for the three performance indicators corresponding to different working state indices.

[0067] Table 1: Performance Index Calibration Data for Different Working State Indices

[0068] To facilitate comparison of the changing trends of the three types of performance indicators and extraction of their intersection boundaries within the same coordinate system, the three types of performance indicators are first normalized and uniformly mapped to a relative value range of 0 to 1. The unit excitation output torque and flux stability are normalized in a positive proportion, while the tension fluctuation is normalized in a negative proportion; a larger value indicates better performance. Specifically: the relative value of torque performance is based on the maximum value of the unit excitation output torque (20.0 Nm / A), and the ratio of the current value to the maximum value is the relative value; a larger value indicates higher torque output efficiency. The relative value of flux stability is based on the maximum value of flux stability under no-load conditions (0.94), and the ratio of the current value to the maximum value is the relative value; a larger value indicates stronger flux disturbance resistance. The relative value of tension performance is based on the maximum value of tension fluctuation (1.70 N) as the worst-case baseline and the minimum value of tension fluctuation (0.50 N) as the best-case baseline. It is converted to a positive relative value using the formula (maximum value - current value) / (maximum value - minimum value); a larger value indicates smaller tension fluctuation and more stable control.

[0069] After normalization, the torque performance curve, flux linkage stability curve, and tension fluctuation curve are generated by fitting the three normalized performance indices onto the horizontal axis and the horizontal axis using the second-order polynomial least squares method. Figure 2 As shown, the fitting process requires a determination coefficient of not less than 0.95, and the three curves fully present the continuous variation law of each performance index with the degree of magnetic saturation.

[0070] Three performance indicators are pre-defined as meeting the following criteria: unit excitation output torque is not less than 80% of its maximum value; flux linkage stability is not less than 85% of the baseline stability under no-load conditions; and tension fluctuation is not greater than 5% of the preset target tension. The operating state index range that simultaneously meets the above three criteria is the intersection and overlap region of the three types of curves. The two boundary values ​​of this intersection and overlap region are extracted, and the lower boundary of the intersection and overlap boundary is determined as the low saturation threshold, and the upper boundary is determined as the high saturation threshold. The interval between the two thresholds is the operating window with optimal comprehensive performance.

[0071] By defining dual thresholds at the intersection of multi-dimensional performance curves, the optimal working range for overall performance is precisely locked, ensuring that the equipment always operates at the best state in terms of torque efficiency, flux stability, and tension control accuracy during continuous long-term slitting operations.

[0072] Furthermore, the method provided in this application embodiment includes: When the target magnetic operating region is an underexcited operating region, target excitation control parameters are generated based on the deviation between the low saturation threshold and the operating state index; when the target magnetic operating region is an effective magnetic operating region, target excitation control parameters are generated based on the effective magnetic operating region defined by the low saturation threshold and the high saturation threshold; when the target magnetic operating region is a magnetically saturated operating region, target excitation control parameters are generated based on the deviation between the operating state index and the high saturation threshold.

[0073] In one embodiment, the determination result of the target magnetic working area in the aforementioned steps is retrieved, and the current working state index, low saturation threshold, and high saturation threshold are obtained simultaneously. For example, when the low saturation threshold is 0.35 and the high saturation threshold is 0.75, the working state index range of the effective magnetic working area is 0.35 to 0.75. The execution cycle of excitation regulation is synchronized with the state determination cycle. Each time the determination update of the target magnetic working area is completed, an excitation parameter calculation and output update are performed. A parameter smoothing transition mechanism is set, ensuring that the change in excitation control parameters between two adjacent outputs does not exceed 2% of the rated excitation current, avoiding sudden parameter changes that could cause tension shocks in the coil. The final generated target excitation control parameters are the given excitation current value, with the global amplitude boundary limited to between 10% and 100% of the rated excitation current to prevent parameter exceeding limits from causing device malfunction or regulation failure. Corresponding excitation regulation logic is matched according to different interval determination results to generate suitable target excitation control parameters.

[0074] When the target magnetic operating region is under-excited, the difference between the low saturation threshold and the current operating state index is first calculated to obtain the state deviation value. This deviation value directly reflects the gap between the current excitation level and entering the effective magnetic operating region. The excitation increment is calculated using a proportional adjustment method. A proportional gain coefficient for the under-excited region is preset, with an example value of 0.12, where the unit is the state index deviation per unit of rated excitation current. The state deviation value is multiplied by the proportional gain coefficient to obtain the excitation current adjustment increment. This adjustment increment is added to the current excitation control parameters. The upper limit of the excitation increment for a single adjustment is set to 5% of the rated excitation current to avoid excessive tension overshoot caused by a single adjustment. By gradually increasing the excitation output, the operating state index is driven up until it enters the effective magnetic operating region.

[0075] When the target magnetic operating area is within the effective magnetic operating area, the arithmetic mean of the low saturation threshold and the high saturation threshold is used as the steady-state target value. A proportional-integral (PI) control method is employed for closed-loop fine-tuning of the excitation parameters. The proportional gain is exemplarily set to 0.05, with units representing the deviation of the state index per unit of rated excitation current. The integral term is used to eliminate steady-state deviations, with an exemplarily set integral time constant of 5 seconds. The integral output limit is set to 3% of the rated excitation current to suppress overshoot caused by integral saturation. The deviation between the current operating state index and the steady-state target value is calculated in real-time, and a small excitation correction is generated based on this deviation. This fine-tuning process compensates for the drift in the operating state index caused by changes in operating conditions such as slitting speed and reduced roll diameter, ensuring that the operating state index remains within the range defined by the low and high saturation thresholds. The adjustment process controls the rate of change of the excitation parameters, avoiding frequent and large adjustments that could cause roll tension fluctuations, and maintaining the optimal balance between torque output efficiency and flux linkage stability.

[0076] When the target magnetic operating area is in the magnetic saturation operating area, the difference between the current operating state index and the high saturation threshold is first calculated to obtain the saturation excess deviation value. This deviation value reflects the extent to which the current magnetic saturation exceeds the optimal operating range. The excitation current adjustment reduction is calculated using a proportional adjustment method. The proportional gain coefficient of the preset saturation range is set, with an example value of 0.1, and the unit is the deviation of the state index per unit of rated excitation current. The saturation excess deviation value is multiplied by the proportional gain coefficient to obtain the excitation reduction amount. The reduction amount is deducted from the current excitation control parameters. The upper limit of the excitation reduction for a single adjustment is set to 4% of the rated excitation current to prevent the excitation reduction speed from being too fast and causing a sudden drop in the coil tension. By gradually reducing the excitation output, the operating state index is pushed back down and returned to the effective magnetic operating range.

[0077] Finally, the generated target excitation control parameters are output to the excitation drive circuit of the magnetic powder brake through the digital-to-analog converter module, and the excitation output amplitude is adjusted in real time. Together with the front-end status acquisition and interval determination, a complete closed loop is formed to complete the dynamic tension adjustment during the operation of the roll material.

[0078] By matching differentiated excitation adjustment strategies, quantized gain parameters, and multiple amplitude constraints to three different magnetic working zones, and combining them with a smooth transition mechanism to achieve stable parameter updates, the dynamic correction and steady-state maintenance of the magnetic powder brake's working state are realized, ensuring that the equipment always operates in the working range with optimal overall performance, thereby improving the accuracy and operational stability of the roll tension control.

[0079] Furthermore, the method provided in this application embodiment includes: The magnetic state evolution sequence is output by recording the working state index in time series; a fluctuation factor is introduced based on the magnetic state evolution sequence to adaptively correct the low saturation threshold and the high saturation threshold.

[0080] Optionally, after initially constructing the low and high saturation thresholds, the output values ​​of the working state index are continuously recorded according to a fixed sampling time sequence. Each time the working state index is calculated, the corresponding value is stored in a time-series storage queue in chronological order. The storage queue has a fixed data length; in this example, it is set to 120 sets of sampled data. The queue is updated using a first-in, first-out (FIFO) rule, always retaining continuous state data from the most recent time period to form a complete magnetic state evolution sequence. This sequence is used to characterize the changing trend and fluctuation amplitude of the magnetic saturation state of the magnetic powder brake within a set time period.

[0081] Next, the fluctuation factor is calculated based on the magnetic state evolution sequence. Specifically: first, the arithmetic mean of all operating state indices within the sequence is calculated; then, the standard deviation of all values ​​within the sequence relative to the mean is calculated; the ratio of the standard deviation to the arithmetic mean is used as the fluctuation factor. A larger fluctuation factor indicates a stronger degree of fluctuation in the magnetic saturation state due to load disturbances, and a weaker stability within the magnetic operating range. A smaller fluctuation factor indicates a more stable operating condition for the equipment, and a smaller fluctuation amplitude in the magnetic saturation state.

[0082] A preset fluctuation baseline value is set, exemplarily 0.08. A threshold correction calculation is performed at fixed intervals, exemplified by a correction period of 60 seconds. This correction period matches the timescale of continuous equipment operation, covering multiple complete disturbance cycles in the continuous slitting operation of the slitting machine. The calculation first calculates the difference between the current fluctuation factor and the fluctuation baseline value. The ratio of this difference to the fluctuation baseline value is used as the deviation ratio. Then, a preset threshold correction coefficient is applied, exemplarily 0.3. The deviation ratio is multiplied by the threshold correction coefficient to obtain the single threshold adjustment ratio.

[0083] The low-saturation and high-saturation thresholds are adjusted symmetrically: when the fluctuation factor is greater than the fluctuation reference value, the low-saturation threshold is simultaneously lowered and the high-saturation threshold is simultaneously raised according to the adjustment ratio, with the absolute values ​​of the adjustment magnitudes of the two thresholds being equal. This widens the effective magnetic working range, reduces the frequency of range switching caused by load disturbances, and enhances the range-keeping capability of the magnetic powder brake under load fluctuation conditions. When the fluctuation factor is less than or equal to the fluctuation reference value, the low-saturation threshold is simultaneously raised and the high-saturation threshold is simultaneously lowered according to the adjustment ratio, with the absolute values ​​of the adjustment magnitudes of the two thresholds being equal. This narrows the effective magnetic working range, enabling the magnetic powder brake to more accurately maintain itself near the optimal operating point under stable operating conditions, improving the steady-state accuracy of tension control. The threshold adjustment magnitude of a single correction does not exceed 15% of the initial calibration threshold to avoid over-correction leading to an offset of the optimal working window.

[0084] After the threshold correction is completed, a smooth transition mechanism is adopted. The difference between the target threshold and the current effective threshold is divided into 10 adjustment steps, and gradually updated to the target threshold over the next 10 judgment cycles. This avoids sudden threshold changes that could cause jumps in the interval judgment results, ensuring a smooth and continuous tension adjustment process. The corrected low saturation threshold and high saturation threshold gradually replace the original threshold parameters and are incorporated into the subsequent target magnetic working area judgment process.

[0085] By tracking the fluctuation patterns of the state in time sequence and symmetrically adjusting the interval boundaries, a threshold update mechanism is realized that dynamically adapts to the fluctuation characteristics of the working conditions. This ensures that the interval judgment logic always matches the current equipment operating state, guaranteeing the stability and control accuracy of tension adjustment in continuous slitting operations of the slitting machine.

[0086] Furthermore, the method provided in this application embodiment includes: The slitting machine includes multiple controllable execution units, including an unwinding shaft, a winding shaft, a main traction pressure roller, and an automatic correction mechanism. Target collaborative control parameters based on the target excitation control parameters are generated according to the target excitation control parameters.

[0087] In one embodiment, the target excitation control parameters of the magnetic powder brake are first obtained, and these parameters are input to the magnetic powder brake drive circuit in the form of an excitation current setpoint. The magnetic powder brake is installed at the end of the unwinding shaft, and its excitation output changes directly alter the braking torque on the unwinding shaft, thereby affecting the tension distribution along the entire roll path. Therefore, it is necessary to generate corresponding target coordinated control parameters for the unwinding shaft, the take-up shaft, the main traction pressure roller, and the automatic correction mechanism.

[0088] The unwinding shaft coordinated control parameters are input using the target excitation control parameters of the magnetic powder brake to calculate the torque compensation of the unwinding shaft drive motor. When the target excitation current increases, the braking torque output by the magnetic powder brake increases. At this time, the coordinated control reduces the setpoint of the drive torque of the unwinding shaft drive motor, and the torque changes of the two cancel each other out, keeping the tension of the roll material output from the unwinding shaft stable. When the target excitation current decreases, the coordinated control increases the setpoint of the drive torque of the unwinding shaft drive motor. The magnitude of the torque compensation is determined according to the torque coupling ratio between the unwinding shaft and the magnetic powder brake, which is determined by the ratio of the rated braking torque of the magnetic powder brake to the rated drive torque of the unwinding shaft motor. When the rated braking torque of the magnetic powder brake is 50 Nm and the rated drive torque of the unwinding shaft motor is 80 Nm, the coupling ratio is 0.625.

[0089] The take-up shaft's coordinated control parameters adapt to tension fluctuations on the unwinding side caused by changes in the magnetic powder brake's excitation. These fluctuations are transmitted along the roll material path to the take-up side. The take-up shaft employs torque control mode, using the deviation between the real-time feedback value from the tension sensor and the target tension as the basis for adjusting the take-up torque. When changes in the target excitation current of the magnetic powder brake cause adjustments in the unwinding tension, the take-up shaft's torque setpoint responds synchronously. When the unwinding tension increases, the take-up torque increases accordingly to maintain constant tension in the slit section; when the unwinding tension decreases, the take-up torque decreases accordingly. The adjustment amount of the take-up torque is calculated based on the tension transmission coefficient of the slit roll material. This coefficient is determined by the combined frictional resistance and wrap angle of each guide roller in the roll material path and can be calibrated by measuring the tension ratio on both the take-up and unwinding sides during steady-state operation of the roll material. The value range is 0.8 to 1.2.

[0090] The main traction pressure roller's control parameters are adapted to the speed reference positioning of the slitting machine. As the speed reference source for the roll material's movement, the main traction pressure roller's linear speed setpoint is not directly affected by the magnetic powder brake's excitation adjustment, thus maintaining a constant slitting speed. The cylinder clamping force of the main traction pressure roller is adjusted to compensate for tension fluctuations. The preset tension deviation dead zone is ±3% of the target tension. When the deviation of the measured tension value from the target value exceeds the dead zone, the pressure relief valve setpoint of the pressure roller cylinder is adjusted accordingly. If the tension is too high, the cylinder clamping force is lowered; if the tension is too low, the cylinder clamping force is raised, ensuring the pressure roller's positive pressure on the roll material remains within the rated range. The clamping force adjustment does not exceed ±5% of the rated pressure to prevent excessive clamping force changes from damaging the roll material surface.

[0091] The automatic web-correcting mechanism's collaborative control parameters are adapted to mitigate the risk of lateral displacement of the web roll caused by excitation fluctuations. Tension fluctuations caused by changes in the magnetic powder brake's excitation can alter the lateral stress distribution of the web roll, potentially inducing edge displacement. The collaborative control parameter of the web-correcting mechanism is a feedforward compensation gain, which is correlated with the rate of change of the target excitation control parameter. The preset excitation change rate threshold is 10% of the rated excitation current per second. When the target excitation current change rate is detected to exceed the threshold, the web-correcting controller adds a feedforward compensation amount to the original PID feedback adjustment. The amplitude of the feedforward amount is proportional to the excitation change rate, and its direction is opposite to the inherent displacement trend of the web roll. The feedforward coefficient is set to 0.08, in millimeters per ampere per second, to improve the response speed of the web-correcting mechanism to large disturbances and suppress the magnitude of web roll edge deviation during magnetic powder brake adjustment.

[0092] The coordinated control parameters for the unwinding shaft, take-up shaft, main traction pressure roller, and automatic correction mechanism are synchronously calculated based on the target excitation control parameters within the same sampling period. These four types of parameters are then distributed to their respective execution unit drive modules within the same control cycle. The magnetic powder brake excitation drive, unwinding shaft motor drive, take-up shaft motor drive, main traction pressure roller pressure regulating valve, and correction drive motor execute actions synchronously according to their respective coordinated parameters. Through the synchronous cooperation of multiple execution units, the entire machine achieves a coordinated response after changes in the magnetic powder brake excitation, ensuring a smooth transition of the coil tension during dynamic adjustment.

[0093] By decoupling the single excitation adjustment of the magnetic powder brake into multi-actuator coordinated control parameters such as unwinding drive force, winding torque, pressure roller clamping force, and correction feedforward amount, the synchronous linkage response of each actuator of the whole machine is realized when the excitation of the magnetic powder brake changes, ensuring the overall machine operation stability and the smooth operation of the roll material during the tension adjustment process.

[0094] In summary, the slitting machine control method based on automatic magnetic powder tension adjustment provided in this application has the following technical effects: This application collects multi-dimensional electromagnetic state characteristics of the magnetic powder brake and slitting machine operating data to quantitatively solve the magnetic saturation trend and load disturbance degree. It identifies the magnetic working range of the magnetic powder brake in different regions and adaptively corrects the threshold. It matches differentiated excitation adjustment parameters and combines multi-mechanism collaborative control of the whole machine to accurately suppress the tension adjustment lag problem caused by magnetic saturation. This effectively improves the dynamic control accuracy and operational stability of the slitting machine's roll tension. It achieves real-time optimal matching of the slitting machine's actuators throughout the entire process, improves the dynamic response speed of the equipment and the accuracy of the finished product, and at the same time suppresses component heat loss and extends service life.

[0095] Example 2, as Figure 3 As shown, based on the same inventive concept as in Embodiment 1 above, this application provides a slitting machine control system based on automatic adjustment of magnetic powder tension, the system comprising: The slitting machine operation status data acquisition module 1 is used to acquire the excitation voltage, excitation current, coil temperature and slitting machine operation status data corresponding to the magnetic powder brake. The slitting machine operation status data includes the unwinding shaft operation status, the winding shaft operation status, the main traction pressure roller operation status, the automatic correction mechanism operation status and tension data.

[0096] The working state index mapping module 2 is used to calculate the electromagnetic state feature set of the magnetic powder brake based on the excitation voltage, excitation current, and coil temperature, analyze the electromagnetic state feature set and the slitting machine operating state data, and map the working state index to obtain a working state index that characterizes the magnetic saturation trend of the magnetic powder brake.

[0097] The target magnetic working area identification module 3 is used to identify the target magnetic working area of ​​the magnetic powder brake according to the working state index. The target magnetic working area includes an underexcited working area, an effective magnetic working area, and a magnetic saturation working area.

[0098] The roll tension adjustment execution module 4 is used to generate target excitation control parameters for adjusting the magnetic powder brake according to the target magnetic working area, so as to maintain the magnetic powder brake performing roll tension adjustment within the effective magnetic working area.

[0099] Furthermore, the working status index mapping module 2 is used to perform the following steps: The electromagnetic state characteristic set of the magnetic powder brake is calculated based on the excitation voltage, excitation current, and coil temperature. This electromagnetic state characteristic set includes at least equivalent inductance characteristics, impedance phase characteristics, and excitation efficiency characteristics. Specifically, the initial inductance characteristic is calculated based on the dynamic differential ratio of the excitation voltage and excitation current. Temperature compensation is performed on the winding resistance of the magnetic powder brake using the coil temperature. The initial inductance characteristic is then corrected based on the compensated winding resistance to obtain the equivalent inductance characteristic. The impedance phase characteristic is obtained by extracting the phase difference between the AC ripple signals of the excitation voltage and the excitation current. The heat loss power is calculated based on the compensated winding resistance. The input power is calculated based on the excitation voltage and excitation current. The excitation efficiency characteristic is obtained based on the power difference between the heat loss power and the input power.

[0100] Furthermore, the working status index mapping module 2 is used to perform the following steps: Based on the equivalent inductance characteristics, impedance phase characteristics, and excitation efficiency characteristics, the magnetic permeability variation capability, unit excitation torque contribution value, and flux linkage stability, which characterize the magnetic saturation trend of the magnetic powder brake, are calculated respectively. The roll material load disturbance degree is calculated based on the slitting machine operating status data. The magnetic permeability variation capability, unit excitation torque contribution value, flux linkage stability degree, and roll material load disturbance degree are subjected to polynomial fusion mapping to generate the working status index.

[0101] Furthermore, the working status index mapping module 2 is used to perform the following steps: The multi-axis speed difference fluctuation value is calculated based on the unwinding line speed, the winding line speed, and the main axis speed of the main traction pressure roller during operation. The speed difference disturbance component is obtained based on this fluctuation value. The axial resistance torque change is calculated based on the correction execution frequency, correction displacement, and correction drive power during operation of the automatic correction mechanism. The correction disturbance component is obtained based on this change in axial resistance torque. The tension error component between the tension data and the preset target tension data is acquired. The speed difference disturbance component, the correction disturbance component, and the tension error component are linearly normalized to obtain the degree of roll material load disturbance.

[0102] Furthermore, the target magnetic working area identification module 3 is used to perform the following steps: By inputting the excitation voltage, excitation current, and coil temperature corresponding to the magnetic powder brake, a low saturation threshold and a high saturation threshold are constructed. If the operating state index is less than the low saturation threshold, the target magnetic operating region is determined to be an under-excited operating region. If the operating state index is greater than or equal to the low saturation threshold and less than or equal to the high saturation threshold, the target magnetic operating region is determined to be an effective magnetic operating region. If the operating state index is greater than the high saturation threshold, the target magnetic operating region is determined to be a magnetically saturated operating region.

[0103] Furthermore, the target magnetic working area identification module 3 is used to perform the following steps: A magnetic state parameter space is constructed based on the excitation voltage, excitation current, and coil temperature. Within the magnetic state parameter space, the unit excitation output torque, flux stability, and tension fluctuation are obtained for different excitation states, and corresponding torque performance curves, flux stability curves, and tension fluctuation curves are constructed respectively. The intersection and coincidence boundary of the torque performance curve, flux stability curve, and tension fluctuation curve are extracted, and the lower boundary of the intersection and coincidence boundary is determined as the low saturation threshold, and the upper boundary is determined as the high saturation threshold.

[0104] Furthermore, the roll tension adjustment execution module 4 is used to perform the following steps: When the target magnetic operating region is an underexcited operating region, target excitation control parameters are generated based on the deviation between the low saturation threshold and the operating state index; when the target magnetic operating region is an effective magnetic operating region, target excitation control parameters are generated based on the effective magnetic operating region defined by the low saturation threshold and the high saturation threshold; when the target magnetic operating region is a magnetically saturated operating region, target excitation control parameters are generated based on the deviation between the operating state index and the high saturation threshold.

[0105] Furthermore, the target magnetic working area identification module 3 is used to perform the following steps: The magnetic state evolution sequence is output by recording the working state index in time series; a fluctuation factor is introduced based on the magnetic state evolution sequence to adaptively correct the low saturation threshold and the high saturation threshold.

[0106] Furthermore, the roll tension adjustment execution module 4 is used to perform the following steps: The slitting machine includes multiple controllable execution units, including an unwinding shaft, a winding shaft, a main traction pressure roller, and an automatic correction mechanism. Target collaborative control parameters based on the target excitation control parameters are generated according to the target excitation control parameters.

[0107] The slitting machine control system based on automatic magnetic powder tension adjustment provided in this embodiment of the invention can execute the slitting machine control method based on automatic magnetic powder tension adjustment provided in any embodiment of the invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0108] Although this application makes various references to certain modules in the system according to the embodiments of this application, any number of different modules can be used and run on user terminals and / or servers. The various units and modules included are only divided according to functional logic, but are not limited to the above division, as long as the corresponding functions can be achieved; in addition, the specific names of each functional unit are only for easy distinction between each other and are not used to limit the scope of protection of this invention.

[0109] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that various modifications, combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application. In some cases, the actions or steps described in this application can be performed in a different order than that shown in the embodiments and still achieve the desired results. Furthermore, the processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

Claims

1. A slitting machine control method based on automatic magnetic powder tension adjustment, characterized in that, The method includes: The excitation voltage, excitation current, coil temperature, and slitting machine operating status data corresponding to the magnetic powder brake are obtained. The slitting machine operating status data includes the unwinding shaft operating status, the winding shaft operating status, the main traction pressure roller operating status, the automatic correction mechanism operating status, and tension data. The electromagnetic state characteristic set of the magnetic powder brake is calculated based on the excitation voltage, excitation current and coil temperature. The electromagnetic state characteristic set and the slitting machine operating status data are analyzed to obtain a working state index that characterizes the magnetic saturation trend of the magnetic powder brake. The target magnetic working zone of the magnetic powder brake is identified according to the working state index. The target magnetic working zone includes an underexcited working zone, an effective magnetic working zone, and a magnetic saturation working zone. Target excitation control parameters are generated according to the target magnetic working area to adjust the magnetic powder brake, so as to maintain the magnetic powder brake performing roll tension adjustment within the effective magnetic working area.

2. The method as described in claim 1, characterized in that, The electromagnetic state characteristic set of the magnetic powder brake is calculated based on the excitation voltage, excitation current and coil temperature. The electromagnetic state characteristic set includes at least the equivalent inductance characteristic, impedance phase characteristic and excitation efficiency characteristic. Specifically, the initial inductance characteristics are calculated based on the dynamic differential ratio of the excitation voltage and the excitation current. The winding resistance of the magnetic powder brake is temperature compensated in conjunction with the coil temperature. The initial inductance characteristics are then corrected based on the compensated winding resistance to obtain the equivalent inductance characteristics. The impedance phase characteristics are obtained by extracting the phase difference between the AC ripple signal of the excitation voltage and the AC ripple signal of the excitation current. The heat loss power is calculated based on the compensated winding resistance, the input power is calculated based on the excitation voltage and excitation current, and the excitation efficiency characteristic is obtained based on the power difference between the heat loss power and the input power.

3. The method as described in claim 2, characterized in that, The method involves analyzing the electromagnetic state feature set and the slitting machine operating state data to map a working state index characterizing the magnetic saturation trend of the magnetic powder brake. Based on the equivalent inductance characteristics, impedance phase characteristics, and excitation efficiency characteristics, respectively calculate the permeability change capability, unit excitation torque contribution value, and flux stability of the magnetic powder brake to characterize the magnetic saturation trend. The degree of roll material load disturbance is calculated based on the slitting machine operating status data. The working state index is generated by performing a polynomial fusion mapping on the magnetic permeability variation capability, unit excitation torque contribution value, magnetic flux stability degree and roll load disturbance degree.

4. The method as described in claim 3, characterized in that, The method for calculating the roll material load disturbance based on the slitting machine operating status data includes: The multi-axis speed difference fluctuation value is calculated based on the unwinding line speed, the winding line speed, and the main axis speed of the main traction pressure roller during the unwinding shaft operation state. The speed difference disturbance component is obtained based on the multi-axis speed difference fluctuation value. The change in axial resistance torque is calculated based on the correction execution frequency, correction displacement, and correction drive power during the operation of the automatic correction mechanism, and the correction disturbance component is obtained based on the change in axial resistance torque. Obtain the tension error component between the tension data and the preset target tension data; The speed difference disturbance component, the correction disturbance component, and the tension error component are linearly normalized to obtain the degree of roll material load disturbance.

5. The method as described in claim 1, characterized in that, The method for identifying the target magnetic working zone of the magnetic particle brake according to the working state index includes: By inputting the excitation voltage, excitation current, and coil temperature corresponding to the magnetic powder brake, low saturation threshold and high saturation threshold are constructed. If the working state index is less than the low saturation threshold, the target magnetic working region is determined to be an underexcited working region. If the working state index is greater than or equal to the low saturation threshold and less than or equal to the high saturation threshold, the target magnetic working area is determined to be an effective magnetic working area. If the working state index is greater than the high saturation threshold, the target magnetic working area is determined to be a magnetic saturation working area.

6. The method as described in claim 5, characterized in that, By inputting the excitation voltage, excitation current, and coil temperature corresponding to the magnetic powder brake, low saturation thresholds and high saturation thresholds are constructed, the method includes: A magnetic state parameter space is constructed based on the excitation voltage, excitation current, and coil temperature. Within the magnetic state parameter space, the unit excitation output torque, flux stability, and tension fluctuation under different excitation states are obtained, and corresponding torque performance curves, flux stability curves, and tension fluctuation curves are constructed respectively. Extract the intersection and coincidence boundary of the torque performance curve, flux linkage stability curve and tension fluctuation curve, and determine the lower boundary of the intersection and coincidence boundary as the low saturation threshold and the upper boundary as the high saturation threshold.

7. The method as described in claim 6, characterized in that, The method for generating target excitation control parameters for adjusting the magnetic powder brake according to the target magnetic working area includes: When the target magnetic operating region is an underexcited operating region, target excitation control parameters are generated based on the deviation between the low saturation threshold and the operating state index. When the target magnetic working area is an effective magnetic working area, target excitation control parameters are generated based on the effective magnetic working area defined by the low saturation threshold and the high saturation threshold. When the target magnetic working area is a magnetically saturated working area, target excitation control parameters are generated based on the deviation between the working state index and the high saturation threshold.

8. The method as described in claim 5, characterized in that, After constructing the low saturation threshold and the high saturation threshold, the method also includes: The magnetic state evolution sequence is output by recording the working state index in time sequence. Based on the magnetic state evolution sequence, a fluctuation factor is introduced to adaptively correct the low saturation threshold and the high saturation threshold.

9. The method as described in claim 1, characterized in that, The slitting machine includes multiple controllable execution units, including an unwinding shaft, a winding shaft, a main traction pressure roller, and an automatic correction mechanism. Target collaborative control parameters based on the target excitation control parameters are generated according to the target excitation control parameters.

10. A slitting machine control system based on automatic magnetic powder tension adjustment, characterized in that, For implementing the slitting machine control method based on automatic magnetic powder tension adjustment as described in any one of claims 1-9, the system comprises: The slitting machine operating status data acquisition module is used to acquire the excitation voltage, excitation current, coil temperature, and slitting machine operating status data corresponding to the magnetic powder brake. The slitting machine operating status data includes the unwinding shaft operating status, the winding shaft operating status, the main traction pressure roller operating status, the automatic correction mechanism operating status, and tension data. The working state index mapping module is used to calculate the electromagnetic state feature set of the magnetic powder brake based on the excitation voltage, excitation current and coil temperature, analyze the electromagnetic state feature set and the slitting machine operating state data, and map to obtain a working state index to characterize the magnetic saturation trend of the magnetic powder brake. The target magnetic working area identification module is used to identify the target magnetic working area of ​​the magnetic powder brake according to the working state index. The target magnetic working area includes an underexcited working area, an effective magnetic working area, and a magnetically saturated working area. The roll tension adjustment execution module is used to generate target excitation control parameters for adjusting the magnetic powder brake according to the target magnetic working area, so as to maintain the magnetic powder brake performing roll tension adjustment within the effective magnetic working area.

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