A segmented start-stop transition control method and system for a web tension controller

Abstract

The present application relates to a kind of sectional type start-stop transition control method and system of coiled material tension controller, belong to coiled material tension control.The present application is by dividing into pre-tightening, open-loop transition, closed-loop operation, open-loop unloading, residual pressure retention and memory storage stage: start-up stage can select fixed output or memory output mode, memory output mode is last shutdown stored closed-loop constant tension control output value multiplied by memory coefficient as start-up pre-tightening control quantity;Open-loop transition stage is according to preset approximation curve continuously adjusts control output quantity, so that tension is smoothly approximated target value;When meeting cut-in condition, current open-loop output is initial value without disturbance cut-in closed-loop constant tension control;Shutdown stage can select integral, filter or fixed level three kinds of unloading mode, according to shutdown coefficient and shutdown time smoothly unloads tension to residual pressure threshold value, and stores the closed-loop output value of shutdown for next start-up reuse.

Description

Technical Field

[0001] This invention relates to the field of roll tension control technology, and in particular to a segmented start-stop transition control method and system for roll tension controllers. Background Technology

[0002] In roll material processing equipment such as printing, coating, laminating, slitting, and unwinding, the stable control of roll material tension directly affects product quality. Excessive tension can easily lead to stretching deformation or even breakage of the roll material, while insufficient tension can easily cause the roll material to loosen, deviate, or wrinkle. Therefore, the roll material tension controller is a core component of various roll material processing equipment.

[0003] Existing roll tension controllers typically employ a closed-loop constant tension control method, which can maintain the roll tension near the target value during normal equipment operation. However, during the transition phases of equipment startup and shutdown, the existing control method has the following drawbacks:

[0004] The lack of a smooth transition during startup results in significant tension shock. Existing controllers often abruptly jump the control output from zero or a fixed value to the operating output value during startup, causing a rapid increase in coil tension and generating noticeable tension shock. This shock causes coil vibration, and in severe cases, wrinkles or breaks, especially when processing thin, low-strength coils. The sudden drop in output during shutdown leads to severe tension fluctuations. Existing controllers typically cut off or rapidly reduce the control output during shutdown, causing a sharp drop in coil tension, which also results in tension fluctuations and material vibration, affecting the processing quality at the tail end of the coil and even causing the coil to unwind at the winding end. Fixed start / stop parameters lack adaptability. Existing controllers typically use preset fixed start-up output values, unable to adaptively adjust based on the actual output state at the time of the previous shutdown. Different coil batches and different process conditions result in variations in the stable output value at shutdown; a fixed start-up output value leads to poor consistency with each startup, potentially causing varying degrees of tension shock. The lack of multi-mode start / stop transition configurations results in insufficient adaptability. Different materials, thicknesses, and elasticities of rolled materials require different start-stop transition curves: thin and brittle materials require slow and smooth start-stop transitions, while thick and tough materials can tolerate faster transition speeds. Existing controllers typically only provide a single start-stop control method, which cannot flexibly adapt to the diverse needs of rolled material processing.

[0005] Therefore, there is an urgent need for a roll tension control method that can eliminate tension shocks during start-up and shutdown, achieve smooth transitions between start-up and shutdown, and has multi-mode adaptive configuration capabilities, in order to solve the technical problems of sudden tension changes, material shaking and wrinkling, and limited overall roll quality in the existing technology. Summary of the Invention

[0006] The main objective of this invention is to provide a segmented start-stop transition control method and system for a roll tension controller, which aims to solve the problems of sudden tension changes, material shaking and wrinkling, and limited overall roll quality during start-stop.

[0007] To achieve the above objectives, the present invention provides a segmented start-stop transition control method for a roll tension controller, comprising the following steps:

[0008] The system acquires startup mode parameters, fixed output value, target tension value, pretension threshold, residual tension threshold, approximation curve type parameters, entry conditions, and memory coefficient. It also receives real-time tension feedback signals and start / stop command signals from the tension sensor. Based on the startup mode parameters, it determines the pretension control quantity. The pretension control quantity is either the fixed output value or the memory output value. The memory output value is calculated from the closed-loop constant tension control output value stored at the last shutdown and the memory coefficient.

[0009] In response to the start command in the start / stop command signal, the current roll tension is determined according to the real-time tension feedback signal, and the pretension control amount is used as the control output amount during the pretensioning stage to gradually build up the current roll tension to the pretensioning threshold.

[0010] When the current coil tension reaches the pretension threshold, it enters the open-loop transition stage. The pretension control amount is used as the initial value of the control output amount. The control output amount is continuously adjusted in an open-loop manner according to the approximation curve type parameter so that the current coil tension smoothly approaches the target tension value from the pretension threshold.

[0011] When the deviation between the current roll tension and the target tension value meets the cut-in condition, the control output is switched from open-loop transition output to closed-loop constant tension control output, and the open-loop transition output at the time of switching is used as the initial output value of closed-loop control. During the operation phase, the roll tension is kept stable until the stop command in the start-stop command signal is valid.

[0012] In response to the shutdown command, the closed-loop constant tension control output when the shutdown command is valid is used as the initial value of the control output quantity, and the control output quantity is continuously adjusted in an open-loop manner to unload the current coil tension from the actual tension during the operation phase to the residual tension threshold.

[0013] When the current coil tension drops to the residual tension threshold, a holding control quantity corresponding to the residual tension threshold is output to maintain the coil's micro-tension. The closed-loop constant tension control output value when the stop command is valid is stored as the final control output value for use in the calculation of the memory output value in the next startup phase.

[0014] Further, the step of responding to the start command, determining the current roll tension based on the real-time tension feedback signal, and using the pretension control amount as the control output amount during the pretensioning stage to gradually build up the current roll tension to the pretension threshold includes:

[0015] When the start command is valid, the preload control quantity is determined and the preload control quantity is output as a control output quantity;

[0016] During the output of the pretension control amount, the current roll tension is determined based on the real-time tension feedback signal;

[0017] When the current tension of the roll material reaches the pretension threshold, the pretensioning stage ends and the open-loop transition stage begins.

[0018] The determination of the pretension control quantity includes: if the start mode parameter is a fixed output mode, then a preset fixed output value is read as the pretension control quantity;

[0019] If the startup mode parameter is memory output mode, then the final control output value stored in the previous shutdown phase is read, and the memory output value is calculated based on the final control output value and the memory coefficient, and the memory output value is used as the pre-tightening control quantity.

[0020] Furthermore, the open-loop transition phase includes:

[0021] The open-loop variation curve of the control output is determined based on the approximation curve type parameter.

[0022] The pretension control amount is used as the initial value of the control output amount in the open-loop transition stage. The control output amount is continuously adjusted in an open-loop manner according to the open-loop change curve, so that the current roll tension smoothly approaches the target tension value from the pretension threshold.

[0023] During the adjustment process, the current roll tension is determined based on the real-time tension feedback signal, and it is determined whether the deviation between the current roll tension and the target tension value meets the cutting condition.

[0024] When the aforementioned cut-in condition is met, the open-loop transition phase ends, and the closed-loop constant tension control phase begins.

[0025] The approximation curve type parameter includes at least one of linear approximation, exponential approximation, and S-shaped approximation.

[0026] Further, the step of switching the control output from open-loop transition output to closed-loop constant tension control output when the deviation between the current roll tension and the target tension value meets the cut-in condition, and using the open-loop transition output at the time of switching as the initial output value of the closed-loop control to maintain stable roll tension during the operation phase until the stop command in the start / stop command signal becomes effective, includes:

[0027] The current roll tension is determined based on the real-time tension feedback signal, and the tension deviation between the current roll tension and the target tension value is calculated.

[0028] Determine whether the tension deviation meets the cut-in condition. When the tension deviation meets the cut-in condition, switch the working mode of the control output from open-loop transition output to closed-loop constant tension control output.

[0029] The open-loop transition output during switching is used as the initial output value of the closed-loop constant tension control, so that the control output changes continuously before and after switching, achieving a bumpless switching from open loop to closed loop.

[0030] During the closed-loop constant tension control output stage, the control output is adjusted according to the real-time tension feedback signal to maintain the current roll tension at the target tension value.

[0031] When the stop command in the start / stop command signal is valid, the closed-loop constant tension control output when the stop command is valid is used as the initial control output quantity for the stop phase.

[0032] Further, the step of responding to the stop command by using the closed-loop constant tension control output when the stop command is valid as the initial value of the control output, and continuously adjusting the control output in an open-loop manner to unload the current coil tension from the actual tension during operation to the residual tension threshold includes:

[0033] Obtain the shutdown mode, shutdown coefficient, and shutdown time;

[0034] The closed-loop constant tension control output when the stop command is valid is used as the initial value of the control output.

[0035] Determine the unloading target value of the control output quantity, wherein the unloading target value is the control output quantity corresponding to the residual pressure tension threshold;

[0036] During the downtime, the control output is continuously adjusted from the initial value to the unloading target value in an open-loop manner according to the downtime mode. The downtime coefficient is used to control the unloading rate of the control output, so that the current coil tension is unloaded from the actual tension of the running stage to the residual tension threshold.

[0037] The shutdown mode includes at least one of the following: integration mode, filtering mode, and fixed level mode.

[0038] Further, the step of outputting a holding control quantity corresponding to the residual tension threshold when the current roll tension drops to the residual tension threshold to maintain the roll tension, and storing the closed-loop constant tension control output value when the stop command is valid as the final control output value for use in the calculation of the memory output value in the next startup phase, includes:

[0039] When the current roll tension drops to the residual tension threshold, a holding control amount is determined based on the residual tension threshold.

[0040] The holding control quantity is output as a control output quantity to maintain the roll tension at the residual pressure tension threshold, thereby maintaining the roll tension at a low level.

[0041] The closed-loop constant tension control output value when the stop command is valid is stored in the memory unit as the final control output value;

[0042] In the next startup phase, when the startup mode parameter is memory output mode, the final control output value stored in the memory unit is read, and the memory output value is calculated by combining the final control output value with the memory coefficient according to a preset calculation relationship.

[0043] Furthermore, after storing the final control output value and before the next startup phase, the method further includes:

[0044] Determine whether a memory clear signal has been received. When the memory clear signal is received, clear the stored final control output value to zero so that the memory output value is not calculated using the final control output value before clearing in the next startup phase.

[0045] If the memory clear signal is not received, the stored final control output value is retained for calculation of the memory output value in the next startup phase.

[0046] Furthermore, the cut-in conditions include:

[0047] The current roll tension is determined based on the real-time tension feedback signal, and the absolute value of the deviation between the current roll tension and the target tension value is calculated.

[0048] When the absolute value of the deviation is not greater than the preset cut-in deviation threshold for a preset stable cut-in period, the cut-in condition is determined to be met.

[0049] Furthermore, the memory clearing signal is a pulse signal. When the effective edge of the pulse signal is detected, the stored final control output value is cleared to zero.

[0050] The present invention also provides a segmented start-stop transition control system for a roll tension controller, comprising:

[0051] The parameter acquisition module is used to acquire start-up mode parameters, fixed output value, target tension value, pretension threshold, residual tension threshold, approximation curve type parameters, cut-in conditions, and memory coefficient. It also receives real-time tension feedback signals and start / stop command signals collected by the tension sensor and determines the pretension control quantity based on the start-up mode parameters. The pretension control quantity is either the fixed output value or the memory output value. The memory output value is calculated from the closed-loop constant tension control output value stored at the last shutdown and the memory coefficient.

[0052] The pretension control module is used to respond to the start command, determine the current tension of the roll material according to the real-time tension feedback signal, and use the pretension control amount as the control output amount during the pretension stage to gradually build up the current tension of the roll material to the pretension threshold.

[0053] An open-loop transition module is used to enter the open-loop transition stage when the current coil tension reaches the pretension threshold. The pretension control amount is used as the initial value of the control output amount, and the control output amount is continuously adjusted in an open-loop manner according to the approximation curve type parameter so that the current coil tension smoothly approaches the target tension value from the pretension threshold.

[0054] The closed-loop control module is used to switch the control output from open-loop transition output to closed-loop constant tension control output when the deviation between the current roll tension and the target tension value meets the cut-in condition, and to use the open-loop transition output at the time of switching as the initial output value of the closed-loop control, so as to maintain the roll tension stability during the operation phase until the stop command in the start-stop command signal is valid.

[0055] The shutdown unloading module is used to respond to the shutdown command in the start / stop command signal, and use the closed-loop constant tension control output when the shutdown command is valid as the initial value of the control output quantity, and continuously adjust the control output quantity in an open-loop manner to unload the current coil tension from the actual tension during the operation stage to the residual pressure tension threshold.

[0056] The storage module is used to output a holding control quantity corresponding to the residual tension threshold when the current roll tension drops to the residual tension threshold, so as to maintain the micro-tension of the roll and store the closed-loop constant tension control output value when the stop command is valid as the final control output value for use in the calculation of the memory output value in the next start-up phase.

[0057] The present invention provides a segmented start-stop transition control method and system for a roll material tension controller, which has the following beneficial effects:

[0058] To eliminate tension shocks during start-up and shutdown, this invention employs multi-stage continuous transition control during both processes: During startup, pre-tension is established first, then the control output is continuously adjusted in an open-loop manner according to a preset approximation curve, smoothly approaching the target value. Once the cut-off condition is met, it seamlessly switches to closed-loop constant tension control. During shutdown, the output is not directly cut off, but rather continuously decreased in an open-loop manner from the current closed-loop output value, allowing the tension to be smoothly unloaded to the residual pressure threshold and maintained at a low tension. The output remains constant throughout the entire process, fundamentally eliminating tension abrupt changes and fluctuations during start-up and shutdown. Start-up is adaptive, ensuring good consistency. It provides two modes: a fixed output mode and a memory output mode. In the memory output mode, the closed-loop constant tension control output value stored from the last shutdown is multiplied by a memory coefficient to use as the start-up pre-tension control value, making the start-up output close to the previous stable operating point. This reduces start-up shocks caused by deviations between the fixed output and the actual operating point, improving start-up consistency across different batches and process conditions. Multiple modes are available for strong adaptability. During the shutdown phase, three unloading modes are provided: integration, filtering, and fixed level. Combined with the shutdown coefficient and shutdown time, the start-stop method and parameters can be flexibly selected according to the material, thickness, and elasticity of the roll. Thin and brittle materials can be started and stopped slowly, while thick and tough materials can be started and stopped quickly, adapting to diverse processing needs. This reduces material loss and improves the overall roll quality. The smooth tension transition during start-stop directly reduces defects such as roll vibration, wrinkling, and breakage, lowering the material loss rate and increasing the overall roll yield. Memory clearing ensures safe process switching. A pulse-triggered memory clearing function is provided; after changing the roll model or process, historical memory values ​​can be cleared, preventing old process parameters from affecting the start of the new process. Attached Figure Description

[0059] Figure 1 This is a schematic flowchart of a segmented start-stop transition control method for a roll material tension controller according to an embodiment of the present invention.

[0060] Figure 2 This is a structural block diagram of a segmented start-stop transition control system for a roll material tension controller according to an embodiment of the present invention;

[0061] Figure 3 This is a timing curve of the roll tension and control output during the start-stop process in one embodiment of the present invention;

[0062] Figure 4 This is a comparison diagram of multi-mode start-stop transition curves in one embodiment of the present invention.

[0063] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0064] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0065] Reference Figure 1 This is a flowchart illustrating a segmented start-stop transition control method for a roll material tension controller proposed in this invention, comprising the following steps:

[0066] S1, acquire the start-up mode parameters, fixed output value, target tension value, pretension threshold, residual tension threshold, approximation curve type parameters, cut-in conditions, and memory coefficient, and receive the real-time tension feedback signal and start / stop command signal collected by the tension sensor. Determine the pretension control quantity according to the start-up mode parameters; the pretension control quantity is the fixed output value or the memory output value, and the memory output value is calculated from the closed-loop constant tension control output value stored at the last shutdown and the memory coefficient.

[0067] Specifically, the tension controller operates with a fixed control cycle, which can be set to 1 millisecond, 5 milliseconds, or 10 milliseconds. The tension controller acquires various control parameters, including start-up mode parameters, start-up level parameters, target tension value, pre-tension threshold, residual tension threshold, approximation curve type parameters, cut-in condition parameters, and memory coefficient, through a human-machine interface or host computer communication interface, and stores these parameters in its internal storage area. Parameters that need to be retained even after power loss (such as start-up mode parameters, memory coefficient, and final control output value) are stored in an electrically erasable programmable read-only memory. The tension controller receives real-time tension feedback signals from the tension sensor through an internal sampling channel, and obtains the current roll tension value after analog-to-digital conversion and digital filtering. The tension controller receives a start command signal through a first digital input terminal, a stop command signal through a second digital input terminal, or a start / stop command signal through a host computer communication interface. The start / stop command signal includes a start command and a stop command. Each digital input terminal has two states: high level and low level. In this embodiment, the low level is the valid level, that is, when the input signal of the corresponding terminal is low, it indicates that the start command or stop command corresponding to that terminal is valid, and when it is high, it indicates that it is invalid.

[0068] The control output of the tension controller is output to the actuator through a digital-to-analog conversion channel or a pulse width modulation channel. The actuator includes at least one of a magnetic powder clutch, a magnetic powder brake, a servo driver, or a pneumatic brake. In this embodiment, the actuator is a magnetic powder brake. The control output is output in the form of an analog current of 0mA to 20mA, corresponding to the excitation current of the magnetic powder brake. The control output is a percentage value of the full scale, with 0% corresponding to no excitation current and 100% corresponding to the full-scale excitation current. The correspondence between the control output and the roll tension is obtained through pre-calibration. The calibration curve is stored in the internal storage area and used to query the corresponding control output based on the target tension value or tension threshold.

[0069] The preload control quantity is determined by the start-up mode parameter, which takes the value 0 or 1: a value of 0 corresponds to a fixed output mode, where the preload control quantity is the simultaneously acquired start-up level parameter (i.e., a fixed output value), and the start-up level parameter ranges from 0 to 100, with the unit being a percentage of full scale; a value of 1 corresponds to a memory output mode, wherein the preload control quantity is calculated based on the final control output value stored during the previous shutdown phase and the acquired memory coefficient, using the following formula:

[0070]

[0071] in, Indicates the preload control amount. This represents the final control output value stored during the previous shutdown phase. This represents the memory coefficient, which ranges from 1 to 100. When the stored final control output value is zero or invalid (such as upon first power-on or after memory clearing), the memory output mode automatically switches to the fixed output mode, using the start-up level parameter as the preload control quantity.

[0072] The cutting condition parameters include a cutting deviation threshold and a cutting stabilization time. The cutting deviation threshold can be set to 1% to 5% of the target tension value, and the cutting stabilization time can be set to 0.1 seconds to 2 seconds.

[0073] Reference Figure 3 From the effective start command to the end of the holding and storage phase, the changes in control output and roll tension over time go through five stages: pre-tensioning, open-loop transition, closed-loop operation, shutdown unloading, and holding and storage, which correspond to steps S2 to S6 below.

[0074] S2, responding to the start command in the start / stop command signal, determining the current roll tension according to the real-time tension feedback signal, and using the pretension control amount as the control output amount in the pretension stage, so that the current roll tension is gradually built up to the pretension threshold.

[0075] Specifically, when the start command in the start / stop command signal changes from invalid to valid, the main control unit in the tension controller triggers a rising edge interrupt, records the current system timestamp as the start time, sets the start status flag, and enters the pre-tightening stage.

[0076] During the pre-tensioning stage, the main control unit outputs the pre-tension control quantity as a control output through a digital-to-analog converter to the magnetic powder brake. In the process of outputting the pre-tension control quantity, the main control unit reads the real-time tension feedback signal from the tension sensor once per control cycle, obtains the current roll tension value after analog-to-digital conversion and moving average filtering, and compares the current roll tension value with the pre-tension threshold. The pre-tension threshold is 30% to 70% of the target tension value.

[0077] When the current roll tension value first reaches or exceeds the pretension threshold, the main control unit records the current system timestamp and marks it as the pretension end time. Simultaneously, it calculates the actual pretension time, switches the start status flag maintained by the main control unit from the pretension state to the open-loop transition state, and ends the pretension stage and enters the open-loop transition stage. If the duration of the pretension stage exceeds the preset pretension timeout threshold, and the current roll tension has not yet reached the pretension threshold, the main control unit determines that the pretension stage has timed out, generates a pretension timeout alarm signal, and forcibly ends the pretension stage and enters the open-loop transition stage. At this time, the current pretension control quantity is used as the initial value of the open-loop transition stage control output quantity. The pretension timeout threshold is set to 1.5 to 2 times the maximum time required for the roll to build up to the pretension threshold from rest.

[0078] S3, when the current coil tension reaches the pretension threshold, the open-loop transition stage is entered. The pretension control amount is used as the initial value of the control output amount. The control output amount is continuously adjusted in an open-loop manner according to the approximation curve type parameter so that the current coil tension smoothly approaches the target tension value from the pretension threshold.

[0079] Specifically, after entering the open-loop transition phase, the main control unit determines the open-loop variation curve of the control output quantity according to the approximation curve type parameter. The approximation curve type parameter takes the value of 0, 1, or 2; where a value of 0 corresponds to linear approximation, a value of 1 corresponds to exponential approximation, and a value of 2 corresponds to S-shaped approximation. The main control unit uses the pre-tension control quantity at the end of the pre-tensioning phase as the initial value of the control output quantity in the open-loop transition phase, and uses the control output quantity corresponding to the target tension value as the target final value of the control output quantity in the open-loop transition phase, and continuously adjusts the control output quantity according to the selected open-loop variation curve within a preset open-loop transition time period. The open-loop transition time period can be set to 0.5 seconds to 30 seconds.

[0080] When the approximation curve type parameter is 0 (linear approximation), the control output changes linearly with time, and the increment for each control cycle is a fixed value. The calculation formula is as follows:

[0081]

[0082] in, This is the control output quantity for the k-th control cycle, where k represents the control cycle number and T is the control cycle. This is the open-loop transition period.

[0083] When the approximation curve type parameter is 1 (exponential approximation), the control output changes according to a first-order inertial element, and the calculation formula is:

[0084]

[0085] in, This represents the time constant, which can be set to 1 / 3 to 1 / 2 of the open-loop transition time period.

[0086] When the approximation curve type parameter is 2 (S-shaped approximation), the control output varies according to a fifth-order polynomial, and the calculation formula is as follows:

[0087]

[0088] Where t represents the time relative to the start time of the open-loop transition phase, t=k×T. The characteristics of the S-shaped approximation are that the rate of change is zero in the initial and final stages, the rate of change is the largest in the middle stage, and the acceleration is continuous throughout the entire process, which can minimize tension impact and mechanical vibration.

[0089] Comparison of the three approximation curves Figure 4 As shown in (a), the linear approximation has a constant rate of change, the exponential approximation changes rapidly at the beginning and slows down in the later stage, and the S-shaped approximation has a zero rate of change at the beginning and end and continuous acceleration throughout the process.

[0090] During the adjustment process of the open-loop transition phase, the main control unit reads the current roll tension value in each control cycle, calculates the absolute value of the deviation between the current roll tension value and the target tension value, and determines whether the absolute value of the deviation meets the cut-in condition. When the cut-in condition is met, the main control unit immediately ends the open-loop transition phase and records the current control output as the open-loop transition output value at the time of switching. And then enter the closed-loop constant tension control stage. Among them, This represents the open-loop transition output value during switching. If the duration of the open-loop transition phase exceeds the open-loop transition time period and the deviation still does not meet the switching condition, the main control unit forcibly terminates the open-loop transition phase at the end of the open-loop transition time period, using the current control output quantity as the open-loop transition output value during switching. It then enters the closed-loop constant tension control stage.

[0091] S4, when the deviation between the current roll tension and the target tension value meets the cut-in condition, the control output is switched from open-loop transition output to closed-loop constant tension control output, and the open-loop transition output at the time of switching is used as the initial output value of closed-loop control to maintain the roll tension stability during the operation phase until the stop command in the start-stop command signal is valid.

[0092] The closed-loop constant tension control output is generated by a closed-loop controller, which is a proportional-integral-derivative (PID) controller deployed inside the main control unit. It is used to calculate the control output in real time based on the deviation between the current roll tension and the target tension value during the closed-loop operation phase, so that the current roll tension is maintained near the target tension value.

[0093] Specifically, the method for determining the entry condition is as follows: based on the absolute value of the deviation between the current roll tension value and the target tension value, an entry stabilization timer is maintained. When the absolute value of the deviation is less than or equal to a preset entry deviation threshold, the entry stabilization timer is incremented by one control cycle; when the absolute value of the deviation is greater than the preset entry deviation threshold, the entry stabilization timer is reset to zero. When the count value of the entry stabilization timer is greater than or equal to a preset entry stabilization duration, the entry condition is determined to be met.

[0094] To perform a seamless handover, the integral term of the closed-loop controller is preset to the open-loop transition output value during the handover. This ensures that the calculated output of the closed-loop controller at the switching moment is equal to... This ensures that the control output changes continuously and without jumps before and after the switch. The closed-loop controller is a proportional-integral-derivative controller, and its output calculation formula is:

[0095]

[0096] in, , , These represent the proportional coefficient, integral coefficient, and differential coefficient, respectively. This represents the tension deviation (target tension value - current roll tension value) in the k-th control cycle, where T is the control cycle. During bumpless switching, the integral accumulation term is... Preset as This ensures that the output of the proportional-integral-derivative controller at the switching moment is exactly equal to the open-loop transient output value at the switching moment. After the switch is completed, the main control unit will switch the working mode of the control output from open-loop transition output to closed-loop constant tension control output, set the running status flag, and enter the closed-loop constant tension control stage.

[0097] During the closed-loop constant tension control phase, the main control unit reads the current roll tension value once per control cycle, calculates the tension deviation, and adjusts the control output in real time using a proportional-integral-derivative (PID) control algorithm to maintain the current roll tension value near the target tension value. To prevent integral saturation, the PID controller is equipped with an output limiting mechanism, restricting the upper and lower limits of the control output to 0%~100% of the full scale; simultaneously, an integral limiting mechanism is set, restricting the upper and lower limits of the integral accumulation term to ±50% of the maximum control output to avoid excessive accumulation of the integral term leading to output overshoot.

[0098] During the closed-loop constant tension control phase, the main control unit continuously monitors the stop command in the start / stop command signal. When the stop command changes from invalid to valid, the main control unit triggers a falling edge interrupt, records the current system timestamp as the stop start time, and records the current closed-loop constant tension control output value. As the initial control output during the shutdown phase The operating status flag is cleared, and the closed-loop constant tension control phase ends, entering the shutdown and unloading phase. Among these steps... This indicates the closed-loop constant tension control output when the stop command is valid. This represents the initial value of the control output during the shutdown and unloading phase.

[0099] S5, in response to the shutdown command, using the closed-loop constant tension control output when the shutdown command is valid as the initial value of the control output, continuously adjusts the control output in an open-loop manner to unload the current roll tension from the actual tension during the operation phase to the residual tension threshold.

[0100] Specifically, after entering the shutdown and unloading phase, the main control unit first obtains the shutdown mode and shutdown coefficient. and downtime .in, The value range is 100~500; The value range is 1 to 200 seconds. The shutdown mode is set through the human-machine interaction unit or the host computer communication interface, and the value is 0, 1 or 2: a value of 0 corresponds to the integration mode, a value of 1 corresponds to the filtering mode, and a value of 2 corresponds to the fixed level mode.

[0101] The main control unit outputs closed-loop constant tension control when the stop command is valid. As the initial value of the control output The control output corresponding to the residual pressure tension threshold is used as the unloading target value. and during the downtime Internally, according to the shutdown mode, it starts from the initial value in an open-loop manner. Start unloading target value Continuously adjust the control output. Among them, This represents the control output quantity corresponding to the unloading target value, i.e., the residual pressure tension threshold. The residual pressure tension threshold is 5% to 20% of the target tension value.

[0102] When the shutdown mode is 0 (integral mode), the control output decreases linearly with time, and the decrease in each control cycle is a fixed value. The calculation formula is as follows:

[0103]

[0104] The integral mode is characterized by a constant unloading speed, making it suitable for scenarios requiring rapid shutdown and high roll material strength.

[0105] When the shutdown mode is 1 (filtered mode), the control output decreases in increments according to the first-order inertial element, and the calculation formula is as follows:

[0106]

[0107] in, This represents the shutdown filtering time constant, which can be set to 1 / 3 to 1 / 2 of the shutdown time. The filtering mode is characterized by rapid unloading in the initial stage and a slower unloading when approaching the residual pressure threshold, which can reduce residual tension fluctuations and is suitable for shutdown scenarios involving thin and brittle materials.

[0108] When the shutdown mode is 2 (fixed level mode), the main control unit will directly switch the control output to a fixed level value when the shutdown command is valid. And maintain this fixed level value throughout the entire downtime. The calculation formula is:

[0109]

[0110] Among them, when When it is 100, It equals the current closed-loop output value, meaning the current output remains unchanged after shutdown; when When it is greater than 100, This value is higher than the current closed-loop output value and is suitable for winding scenarios where a high tension needs to be maintained during the shutdown phase to prevent the roll material from unwinding. In fixed-level mode, the end of the shutdown unloading phase is used as the end condition for the shutdown time, and the tension dropping to the residual tension threshold is no longer used as the judgment criterion; when the shutdown time ends, the current fixed-level value is used as the holding control quantity to enter the holding storage phase.

[0111] Comparison of the three uninstallation modes Figure 4 As shown in (b): the unloading rate is constant in integral mode, fast in filter mode at the beginning and slows down when it approaches the residual voltage threshold, and the output of fixed level mode switches to a fixed value in one step and then remains there.

[0112] During the shutdown and unloading phase, for both integral and filtering modes, the main control unit reads the current coil tension value and compares it with the residual tension threshold. When the current coil tension value first drops to or below the residual tension threshold, the main control unit records the current system timestamp as the unloading end time, ends the shutdown and unloading phase, and enters the storage phase. If the shutdown and unloading phase lasts longer than the shutdown time... If the current coil tension has not yet dropped to the residual tension threshold, the main control unit will forcibly end the shutdown unloading phase at the end of the shutdown time and enter the holding storage phase with the current control output.

[0113] S6, when the current coil tension drops to the residual tension threshold, output the holding control quantity corresponding to the residual tension threshold to maintain the coil micro-tension, and store the closed-loop constant tension control output value when the stop command is valid as the final control output value for use in the calculation of the memory output value in the next start-up phase.

[0114] Specifically, after entering the holding and storage phase, the main control unit determines the holding control quantity based on the residual tension threshold. The holding control quantity is the control output quantity required to maintain the coil tension at the residual tension threshold. In integral and filter modes, the current control output quantity at the end of the shutdown and unloading phase is used as the holding control quantity; in fixed-level mode, a fixed level value is used. As a control quantity.

[0115] The main control unit continuously outputs the holding control quantity as a control output to the magnetic powder brake, maintaining the coil tension near the residual tension threshold to maintain micro-tension of the coil and prevent slack, deviation, or loosening at the winding end. This micro-tension is the minimum tension required to prevent coil slack, typically 5% to 20% of the target tension value. The holding storage phase continues until the next start command is valid; when the next start command is detected, the main control unit directly switches from the holding storage phase to the pre-tensioning phase, replacing the holding control quantity output with the pre-tensioning control quantity of the new start cycle.

[0116] While maintaining the control output, the main control unit will record the closed-loop constant tension control output value when the stop command is valid. As the final control output value Write to the electrically erasable programmable read-only memory (EEPROM) at a preset memory address, and write data as a percentage (0-100) of the final control output value. To prevent frequent writes from damaging the memory, the main control unit is equipped with a write debouncing mechanism: the write operation is only performed when the difference between the final control output value and the previous stored value exceeds a preset difference threshold; otherwise, the previous stored value is retained.

[0117] During the next startup phase, when the startup mode parameter is 1 (memory output mode), the main control unit reads the stored final control output value from the electrically erasable programmable read-only memory. And according to the formula in step S1 The memory output value is calculated and used as the preload control variable.

[0118] After storing the final control output value and before the next startup phase, the main control unit also performs a memory clearing check: detecting whether a memory clearing signal has been received. The memory clearing signal is a pulse signal received via a digital input terminal or a host computer communication interface. When a valid edge of the memory clearing pulse signal is detected, the main control unit stores the final control output value in the electrically erasable programmable read-only memory. The memory is reset to zero so that the final control output value before the reset is not used to calculate the memory output value in the next startup phase. When no memory reset signal is received, the stored final control output value is retained for calculation in the next startup phase. The memory reset function is suitable for scenarios such as changing the roll material type, changing process parameters, or restarting the equipment after a long period of shutdown, to avoid the historical memory values ​​of the old process affecting the startup effect of the new process.

[0119] Reference Figure 2 The diagram shows a segmented start-stop transition control system for a roll material tension controller according to an embodiment of the present invention, comprising: The parameter acquisition module is used to acquire start-up mode parameters, fixed output value, target tension value, pretension threshold, residual tension threshold, approximation curve type parameters, cut-in conditions, and memory coefficient. It also receives real-time tension feedback signals and start / stop command signals collected by the tension sensor and determines the pretension control quantity based on the start-up mode parameters. The pretension control quantity is either the fixed output value or the memory output value. The memory output value is calculated from the closed-loop constant tension control output value stored at the last shutdown and the memory coefficient. The pretension control module is used to respond to the start command, determine the current tension of the roll material according to the real-time tension feedback signal, and use the pretension control amount as the control output amount during the pretension stage to gradually build up the current tension of the roll material to the pretension threshold. An open-loop transition module is used to enter the open-loop transition stage when the current coil tension reaches the pretension threshold. The pretension control amount is used as the initial value of the control output amount, and the control output amount is continuously adjusted in an open-loop manner according to the approximation curve type parameter so that the current coil tension smoothly approaches the target tension value from the pretension threshold. The closed-loop control module is used to switch the control output from open-loop transition output to closed-loop constant tension control output when the deviation between the current roll tension and the target tension value meets the cut-in condition, and to use the open-loop transition output at the time of switching as the initial output value of the closed-loop control, so as to maintain the roll tension stability during the operation phase until the stop command in the start-stop command signal is valid. The shutdown unloading module is used to respond to the shutdown command in the start / stop command signal, and use the closed-loop constant tension control output when the shutdown command is valid as the initial value of the control output quantity, and continuously adjust the control output quantity in an open-loop manner to unload the current coil tension from the actual tension during the operation stage to the residual pressure tension threshold. The storage module is used to output a holding control quantity corresponding to the residual tension threshold when the current roll tension drops to the residual tension threshold, so as to maintain the micro-tension of the roll and store the closed-loop constant tension control output value when the stop command is valid as the final control output value for use in the calculation of the memory output value in the next start-up phase.

[0120] For the specific implementation of each module in the above system example, please refer to the above method embodiments, which will not be repeated here.

[0121] In summary, this invention divides the start-up and shutdown process into pre-tensioning, open-loop transition, closed-loop operation, open-loop unloading, residual pressure holding, and memory storage stages. During the start-up stage, a fixed output or memory output mode can be selected. In the memory output mode, the closed-loop constant tension control output value stored from the previous shutdown is multiplied by a memory coefficient to obtain the start-up pre-tensioning control quantity. During the open-loop transition stage, the control output quantity is continuously adjusted according to a preset approximation curve to smoothly approach the target tension value. When the cut-in condition is met, the current open-loop output is used as the initial value for seamless cut-in to closed-loop constant tension control. During the shutdown stage, three unloading modes can be selected: integral, filtered, or fixed level. The tension is smoothly unloaded to the residual pressure threshold according to the shutdown coefficient and shutdown time, and the closed-loop output value at the time of shutdown is stored for reuse during the next start-up. This invention eliminates tension impact and fluctuations at the moment of start-up and shutdown, reduces material vibration, wrinkling, and strip breakage, and improves the overall roll quality.

[0122] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, apparatus, article, or method that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, apparatus, article, or method. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, apparatus, article, or method that includes that element.

[0123] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A segmented start-stop transition control method for a roll material tension controller, characterized in that, Includes the following steps: The system acquires startup mode parameters, fixed output value, target tension value, pretension threshold, residual tension threshold, approximation curve type parameters, entry conditions, and memory coefficient. It also receives real-time tension feedback signals and start / stop command signals collected by the tension sensor. Based on the startup mode parameters, the system determines the pretension control quantity, which is either the fixed output value or the memory output value. The memory output value is calculated from the closed-loop constant tension control output value stored at the last shutdown and the memory coefficient. In response to the start command in the start / stop command signal, the current roll tension is determined according to the real-time tension feedback signal, and the pretension control amount is used as the control output amount during the pretensioning stage to gradually build up the current roll tension to the pretensioning threshold. When the current coil tension reaches the pretension threshold, it enters the open-loop transition stage. The pretension control amount is used as the initial value of the control output amount. The control output amount is continuously adjusted in an open-loop manner according to the approximation curve type parameter so that the current coil tension smoothly approaches the target tension value from the pretension threshold. When the deviation between the current roll tension and the target tension value meets the cut-in condition, the control output is switched from open-loop transition output to closed-loop constant tension control output, and the open-loop transition output at the time of switching is used as the initial output value of closed-loop control. During the operation phase, the roll tension is kept stable until the stop command in the start-stop command signal is valid. In response to the shutdown command, the closed-loop constant tension control output when the shutdown command is valid is used as the initial value of the control output quantity, and the control output quantity is continuously adjusted in an open-loop manner to unload the current coil tension from the actual tension during the operation phase to the residual tension threshold. When the current coil tension drops to the residual tension threshold, a holding control quantity corresponding to the residual tension threshold is output to maintain the coil's micro-tension. The closed-loop constant tension control output value when the stop command is valid is stored as the final control output value for use in the calculation of the memory output value in the next startup phase.

2. The segmented start-stop transition control method for the roll tension controller according to claim 1, characterized in that, The steps of responding to the start command in the start / stop command signal, determining the current roll tension based on the real-time tension feedback signal, and using the pretension control amount as the control output amount during the pretensioning stage to gradually build up the current roll tension to the pretensioning threshold include: When the start command is valid, the preload control quantity is determined and the preload control quantity is output as a control output quantity; During the output of the pretension control amount, the current roll tension is determined based on the real-time tension feedback signal; When the current tension of the roll material gradually builds up to the pretension threshold, the pretensioning stage ends and the open-loop transition stage begins. The determination of the pretension control quantity includes: if the start mode parameter is a fixed output mode, then a preset fixed output value is read as the pretension control quantity; If the startup mode parameter is memory output mode, then the final control output value stored in the previous shutdown phase is read, and the memory output value is calculated based on the final control output value and the memory coefficient, and the memory output value is used as the pre-tightening control quantity.

3. The segmented start-stop transition control method for the roll tension controller according to claim 1, characterized in that, The open-loop transition phase includes: The open-loop variation curve of the control output is determined based on the approximation curve type parameter. The pretension control amount is used as the initial value of the control output amount in the open-loop transition stage. The control output amount is continuously adjusted in an open-loop manner according to the open-loop change curve, so that the current roll tension smoothly approaches the target tension value from the pretension threshold. During the adjustment process, the current roll tension is determined based on the real-time tension feedback signal, and it is determined whether the deviation between the current roll tension and the target tension value meets the cutting condition. When the aforementioned cut-in condition is met, the open-loop transition phase ends, and the closed-loop constant tension control phase begins. The approximation curve type parameter includes at least one of linear approximation, exponential approximation, and S-shaped approximation.

4. The segmented start-stop transition control method for the roll tension controller according to claim 1, characterized in that, The step of switching the control output from open-loop transition output to closed-loop constant tension control output when the deviation between the current roll tension and the target tension value meets the cut-in condition, and using the open-loop transition output at the time of switching as the initial output value of the closed-loop control to maintain stable roll tension during the operation phase until the stop command in the start / stop command signal becomes effective, includes: The current roll tension is determined based on the real-time tension feedback signal, and the tension deviation between the current roll tension and the target tension value is calculated. Determine whether the tension deviation meets the cut-in condition. When the tension deviation meets the cut-in condition, switch the working mode of the control output from open-loop transition output to closed-loop constant tension control output. The open-loop transition output during switching is used as the initial output value of the closed-loop constant tension control, so that the control output changes continuously before and after switching, achieving a bumpless switching from open loop to closed loop. During the closed-loop constant tension control output stage, the control output is adjusted according to the real-time tension feedback signal to maintain the current roll tension at the target tension value. When the stop command in the start / stop command signal is valid, the closed-loop constant tension control output when the stop command is valid is used as the initial control output quantity for the stop phase.

5. The segmented start-stop transition control method for the roll tension controller according to claim 1, characterized in that, The step of responding to the stop command, using the closed-loop constant tension control output when the stop command is valid as the initial value of the control output, and continuously adjusting the control output in an open-loop manner to unload the current coil tension from the actual tension during operation to the residual tension threshold includes: Obtain the shutdown mode, shutdown coefficient, and shutdown time; The closed-loop constant tension control output when the stop command is valid is used as the initial value of the control output. Determine the unloading target value of the control output quantity, wherein the unloading target value is the control output quantity corresponding to the residual pressure tension threshold; During the downtime, the control output is continuously adjusted from the initial value to the unloading target value in an open-loop manner according to the downtime mode. The downtime coefficient is used to control the unloading rate of the control output, so that the current coil tension is unloaded from the actual tension of the running stage to the residual tension threshold. The shutdown mode includes at least one of the following: integration mode, filtering mode, and fixed level mode.

6. The segmented start-stop transition control method for the roll tension controller according to claim 1, characterized in that, The step of outputting a holding control quantity corresponding to the residual tension threshold when the current coil tension drops to the residual tension threshold to maintain the coil's micro-tension, and storing the closed-loop constant tension control output value when the stop command is valid as the final control output value for use in calculating the memory output value in the next startup phase, includes: When the current roll tension drops to the residual tension threshold, a holding control amount is determined based on the residual tension threshold. The holding control quantity is output as a control output quantity to maintain the roll tension at the residual pressure tension threshold, thereby maintaining the roll tension at a low level. The closed-loop constant tension control output value when the stop command is valid is stored as the final control output value in the memory unit; In the next startup phase, when the startup mode parameter is memory output mode, the final control output value stored in the memory unit is read, and the memory output value is calculated by combining the final control output value with the memory coefficient according to a preset calculation relationship.

7. The segmented start-stop transition control method for the roll tension controller according to claim 6, characterized in that, After storing the final control output value and before the next startup phase, the process also includes: Determine whether a memory clear signal has been received. When the memory clear signal is received, clear the stored final control output value to zero so that the memory output value is not calculated using the final control output value before clearing in the next startup phase. If the memory clear signal is not received, the stored final control output value is retained for calculation of the memory output value in the next startup phase.

8. The segmented start-stop transition control method for the roll tension controller according to claim 1, characterized in that, The cut-in conditions include: The current roll tension is determined based on the real-time tension feedback signal, and the absolute value of the deviation between the current roll tension and the target tension value is calculated. When the absolute value of the deviation is not greater than the preset cut-in deviation threshold for a preset stable cut-in period, the cut-in condition is determined to be met.

9. The segmented start-stop transition control method for the roll tension controller according to claim 7, characterized in that, The memory clear signal is a pulse signal. When the effective edge of the pulse signal is detected, the stored final control output value is cleared.

10. A segmented start-stop transition control system for a roll material tension controller, characterized in that, include: The parameter acquisition module is used to acquire start-up mode parameters, fixed output value, target tension value, pretension threshold, residual tension threshold, approximation curve type parameters, cut-in conditions, and memory coefficient. It also receives real-time tension feedback signals and start / stop command signals collected by the tension sensor and determines the pretension control quantity based on the start-up mode parameters. The pretension control quantity is either the fixed output value or the memory output value. The memory output value is calculated from the closed-loop constant tension control output value stored at the last shutdown and the memory coefficient. The pretension control module is used to respond to the start command in the start / stop command signal, determine the current roll tension according to the real-time tension feedback signal, and use the pretension control amount as the control output amount in the pretension stage to gradually build up the current roll tension to the pretension threshold. An open-loop transition module is used to enter the open-loop transition stage when the current coil tension reaches the pretension threshold. The pretension control amount is used as the initial value of the control output amount, and the control output amount is continuously adjusted in an open-loop manner according to the approximation curve type parameter so that the current coil tension smoothly approaches the target tension value from the pretension threshold. The closed-loop control module is used to switch the control output from open-loop transition output to closed-loop constant tension control output when the deviation between the current roll tension and the target tension value meets the cut-in condition, and to use the open-loop transition output at the time of switching as the initial output value of the closed-loop control, so as to maintain the roll tension stability during the operation phase until the stop command in the start-stop command signal is valid. The shutdown unloading module is used to respond to the shutdown command, using the closed-loop constant tension control output when the shutdown command is valid as the initial value of the control output quantity, and continuously adjusting the control output quantity in an open-loop manner to unload the current coil tension from the actual tension during the operation phase to the residual pressure tension threshold. The storage module is used to output a holding control quantity corresponding to the residual tension threshold when the current roll tension drops to the residual tension threshold, so as to maintain the micro-tension of the roll and store the closed-loop constant tension control output value when the stop command is valid as the final control output value for use in the calculation of the memory output value in the next start-up phase.

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