A paper tube tension control system and method

Abstract

This application discloses a paper tube tension control system and method, relating to the field of paper tube tension control. The scheme uses a programmable logic controller (PLC) to pre-differentiate between thin and thick paper tubes based on their inner diameter, and sets corresponding roll diameter and tension deviation thresholds. During production, roll diameter and tension signals are collected and processed in real time to accurately capture state changes at the end of unwinding. This scheme implements a differentiated automatic pressure relief strategy: when a thin paper tube is identified and its roll diameter shrinks to a preset threshold, the system generates a gradual pressure reduction command in advance, switching the expansion / contraction cylinder valve to the neutral position for smooth pressure relief, preventing the thin paper tube from breaking due to momentary unloading; when a thick paper tube is identified and a loss of tension signal is generated after complete unwinding, the system generates an immediate cut-off command, de-energizing the valve to quickly return the pressure to zero, thereby achieving intelligent and adaptive control of the expansion / contraction cylinder pressure, effectively eliminating the risk of paper tube breakage and ensuring efficient and continuous production.

Description

Technical Field

[0001] This application relates to the field of paper tube tension control, and more specifically, to a paper tube tension control system and method. Background Technology

[0002] In the strip processing of continuous production lines such as color coating, the uncoiler is an indispensable key piece of equipment. Its main function is to smoothly unwind the loaded steel coil, providing a stable strip for subsequent continuous production processes. In practical applications, the steel coil is usually lined with a paper tube. The uncoiler applies radial tension outward through an internal expansion cylinder to fix the paper tube and the steel coil, thereby ensuring stable rotation and tension maintenance throughout the unwinding process. Therefore, rationally constructing and optimizing the control scheme of paper tube tension and expansion cylinder pressure is of paramount importance for ensuring smooth unwinding of the steel coil, protecting the load-bearing components, and maintaining the continuous and stable operation of the production line.

[0003] However, existing paper tube tension control schemes mainly rely on a single, mechanical, continuous pressurization mode, lacking intelligent adaptive adjustment mechanisms for the final unwinding stage and different paper tube types, resulting in significant shortcomings. In actual operation, after the base plate of a steel coil is unwound, the operator needs to immediately transfer to another uncoiler for welding and other connection operations. At this time, the unwound uncoiler is temporarily idle, but the existing control system cannot automatically detect the unwinding process, causing the tension cylinder to remain in a high-pressure tensioning and oil supply state. Since the external steel coil has been completely released, the paper tube is in an unloaded state and has lost the radial restraint and support of the steel coil. Under the continuous and enormous radial pressure from the tension cylinder, the paper tube is extremely prone to deformation and breakage.

[0004] More seriously, existing technologies lack differentiated identification and control methods for different types of paper tubes. In actual production, paper tubes of varying thicknesses are used. Thinner paper tubes have lower structural strength and are prone to frequent breakage if pressure is not released in advance near the end of unwinding. While thicker paper tubes can withstand greater pressure, they will also be damaged if pressure is not quickly cut off after unwinding. Because existing systems fail to effectively integrate roll diameter detection and tension monitoring signals for comprehensive logical judgment, they cannot implement advance gradual pressure reduction or rapid cutting control after tension loss based on whether the paper tube is thin-walled or thick-walled. This one-size-fits-all control blind spot results in a persistently high paper tube breakage rate, significantly increasing equipment maintenance and consumable costs, and frequently causing production interruptions due to debris cleanup, severely hindering overall production efficiency. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, this application provides a paper tube tension control method, comprising: Step 1: using a programmable logic controller (PLC) to determine the paper tube type based on the inner diameter of the paper tube to obtain a roll diameter threshold, and setting a tension deviation threshold; Step 2: filtering the roll diameter signal and tension signal collected by the roll diameter detection sensor and tension detection sensor to obtain the current roll diameter and current tension; Step 3: using a PLC to perform logical judgment on the current roll diameter, current tension, roll diameter threshold, and tension deviation threshold to obtain a roll diameter trigger signal and a tension loss trigger signal; Step 4: using the PLC to... The programmable logic controller (PLC) performs logical judgments based on the roll diameter trigger signal, the tension loss trigger signal, and the paper tube type. When the paper tube type is a thin paper tube and the roll diameter trigger signal is received, a gradual pressure reduction command is generated. When the paper tube type is a thick paper tube and the tension loss trigger signal is received, an immediate cut-off command is generated to obtain control commands. Step 5: Based on the control commands, the PLC controls the expansion cylinder valve. When the control command is a gradual pressure reduction command, the expansion cylinder valve is switched to the neutral position and the expansion cylinder pressure is reduced at a preset pressure reduction rate. When the control command is an immediate cut-off command, the expansion cylinder valve is de-energized to quickly reduce the expansion cylinder pressure to zero.

[0006] This application also provides a paper tube tension control system, comprising: a roll diameter threshold generation module, used to determine the paper tube type based on the inner diameter of the paper tube using a programmable logic controller to obtain a roll diameter threshold, and to set a tension deviation threshold; a signal filtering module, used to filter the roll diameter signal and tension signal collected by the roll diameter detection sensor and the tension detection sensor to obtain the current roll diameter and the current tension; a trigger signal generation module, used to perform logical judgment on the current roll diameter, the current tension, the roll diameter threshold, and the tension deviation threshold using a programmable logic controller to obtain a roll diameter trigger signal and a tension loss trigger signal; and an instruction generation module, used to transmit... The programmable logic controller (PLC) performs logical judgments based on the roll diameter trigger signal, the tension loss trigger signal, and the paper tube type. When the paper tube type is a thin paper tube and the roll diameter trigger signal is received, a gradual pressure reduction command is generated. When the paper tube type is a thick paper tube and the tension loss trigger signal is received, an immediate cut-off command is generated to obtain control commands. The control module is used to control the expansion cylinder valve through the PLC based on the control commands. When the control command is a gradual pressure reduction command, the expansion cylinder valve is switched to the neutral position and the expansion cylinder pressure is reduced at a preset pressure reduction rate. When the control command is an immediate cut-off command, the expansion cylinder valve is de-energized to quickly return the expansion cylinder pressure to zero.

[0007] Compared with existing technologies, this application provides a paper tube tension control system and method aimed at solving the technical problem of paper tube breakage caused by continuous pressure application of the expansion cylinder and lack of differentiated control at the end of unwinding in an uncoiler. This solution uses a programmable logic controller (PLC) to pre-differentiate between thin and thick paper tubes based on their inner diameter and sets corresponding roll diameter and tension deviation thresholds. During production, the system collects and processes roll diameter and tension signals in real time, thereby accurately capturing state changes at the end of unwinding. Addressing the shortcomings of existing technologies that rely solely on continuous pressure application, this solution implements a differentiated automatic pressure relief strategy: when a thin paper tube is identified and its roll diameter shrinks to a preset threshold, the system generates a gradual pressure reduction command in advance, switching the expansion cylinder valve to the neutral position for smooth pressure relief, preventing breakage of the thin paper tube due to momentary unloading; when a thick paper tube is identified and a loss of tension signal is generated after complete unwinding, the system generates an immediate cut-off command, de-energizing the valve to quickly return the pressure to zero, thus achieving intelligent and adaptive control of the expansion cylinder pressure, effectively eliminating the risk of paper tube breakage and ensuring efficient and continuous production. Attached Figure Description

[0008] The above and other objects, features and advantages of this application will become more apparent from the more detailed description of the embodiments of this application in conjunction with the accompanying drawings.

[0009] Figure 1 This is a flowchart of a paper tube tension control method according to an embodiment of this application.

[0010] Figure 2 This is a schematic diagram of the data flow of a paper tube tension control method according to an embodiment of this application.

[0011] Figure 3 This is a flowchart of step 3 in the paper tube tension control method according to an embodiment of this application.

[0012] Figure 4 This is a flowchart of step 4 in the paper tube tension control method according to an embodiment of this application.

[0013] Figure 5 This is a block diagram of a paper tube tension control system according to an embodiment of this application.

[0014] Among them, 100 is the paper tube tension control system; 110 is the roll diameter threshold generation module; 120 is the signal filtering module; 130 is the trigger signal generation module; 140 is the instruction generation module; and 150 is the control module. Detailed Implementation

[0015] The embodiments of this application will now be described in more detail with reference to the accompanying drawings. It should be understood that the drawings and embodiments of this application are for illustrative purposes only and are not intended to limit the scope of protection of this application.

[0016] In view of the shortcomings in the above-mentioned technical field, this application proposes a paper tube tension control method. Figure 1 This is a flowchart of a paper tube tension control method according to an embodiment of this application. Figure 2 This is a schematic diagram of the data flow in a paper tube tension control method according to an embodiment of this application. Figure 1 and Figure 2 As shown, the paper roll tension control method according to an embodiment of this application includes: Step 1: using a programmable logic controller (PLC) to determine the paper roll type based on the inner diameter of the paper roll to obtain a roll diameter threshold, and setting a tension deviation threshold; Step 2: filtering the roll diameter signal and tension signal collected by the roll diameter detection sensor and tension detection sensor to obtain the current roll diameter and current tension; Step 3: using a PLC to perform logical judgment on the current roll diameter, current tension, roll diameter threshold, and tension deviation threshold to obtain a roll diameter trigger signal and a tension loss trigger signal; Step 4: using a PLC to... Logical judgment is performed based on the roll diameter trigger signal, the tension loss trigger signal, and the paper tube type. When the paper tube type is a thin paper tube and the roll diameter trigger signal is received, a gradual pressure reduction command is generated. When the paper tube type is a thick paper tube and the tension loss trigger signal is received, an immediate cut-off command is generated to obtain the control command. Step 5: Based on the control command, the expansion cylinder valve is controlled by the programmable logic controller. When the control command is a gradual pressure reduction command, the expansion cylinder valve is switched to the neutral position and the expansion cylinder pressure is reduced at a preset pressure reduction rate. When the control command is an immediate cut-off command, the expansion cylinder valve is de-energized to quickly reduce the expansion cylinder pressure to zero.

[0017] Step 1: The programmable logic controller (PLC) determines the paper tube type based on its inner diameter to obtain a roll diameter threshold and sets a tension deviation threshold. It should be understood that during the unwinding process of continuous strip processing, the paper tube bears the weight of the steel coil and is subjected to the radial tension force of the expansion cylinder. Its stress state changes dynamically as the steel coil is continuously consumed. Especially towards the end of unwinding, paper tubes of different thicknesses exhibit drastically different mechanical response characteristics. Thin paper tubes are prone to deformation and breakage when the remaining steel coil is small due to their thin walls, while thick paper tubes maintain structural stability until complete unwinding. Introducing the process of determining the paper tube type based on its inner diameter using the PLC to obtain a roll diameter threshold and setting a tension deviation threshold allows for the pre-construction of differentiated monitoring benchmarks for different materials and structural strengths. By precisely assigning dedicated roll diameter trigger limits and tension sensitivity to paper tubes with different properties, reliable logical judgment boundaries can be provided for the generation of subsequent control commands, avoiding the potential for paper tube breakage caused by a one-size-fits-all pressure mode.

[0018] In one implementation, the operational details of step 1 are as follows: First, the input interface of the programmable logic controller (PLC) reads in real time the paper tube type parameter and the paper tube inner diameter parameter selected and issued by the operator on the human-machine interface. The PLC's built-in verification module checks the legality of the received paper tube type, determining whether the parameter strictly belongs to a predefined type set. This predefined set contains only two valid character items: thin paper tube and thick paper tube. If the read character does not belong to the above set, the PLC immediately triggers a parameter abnormality alarm command and prompts the operator to re-select and input through the human-machine interface; if the verification passes, the valid character is assigned to the verified paper tube type variable. Simultaneously, the PLC verifies the range of physical constraints for the received paper tube inner diameter parameter. This verification process relies on the core inequality formula. Expand. In this formula, The minimum safe inner diameter limit of the paper tube is preset in the characterization control architecture. Characterizes the initial full-load coil diameter when the uncoiler loads steel coils. This is the actual paper tube inner diameter value entered by the operator. If the entered paper tube inner diameter fails to fall within the safe range defined by this inequality, a parameter abnormality alarm will also be triggered; if the condition is met, it will be assigned to the verified paper tube inner diameter variable. For example, if the minimum safe paper tube inner diameter limit is set to 400 mm and the initial full-load roll diameter is 1500 mm, when the operator enters 505 mm, it fully meets the range constraint, and this value is confirmed as the verified paper tube inner diameter.

[0019] After verifying and assigning values ​​to the basic parameters, the programmable logic controller (PLC) executes a flow-division processing strategy based on the verified paper roll type to generate a roll diameter threshold suitable for the current production conditions. Specifically, in one embodiment, when the paper roll type is a thin paper roll, the roll diameter threshold is set to a value greater than the inner diameter of the paper roll; when the paper roll type is a thick paper roll, the roll diameter threshold is set to a value less than or equal to the inner diameter of the paper roll. Specifically, when the verified paper roll type is equal to a thin paper roll, the control program enters the thin paper roll control strategy branch. At this time, the PLC reads the roll diameter offset ratio specifically for thin paper rolls from the configuration table. This ratio is strictly set to a positive range, typically between 2% and 5%. The roll diameter threshold is calculated according to the formula... In this mathematical relationship, The threshold representing the final output volume diameter. This represents the verified inner diameter of the paper tube. This represents the read roll diameter offset ratio. Because thin paper tubes have lower structural strength, the pressure reduction action needs to be initiated while a small amount of strip material is still wrapped around them. Therefore, assigning a positive offset ratio ensures that the roll diameter threshold is significantly larger than the inner diameter of the paper tube. For example, when the verified inner diameter of the paper tube is 505 mm and the offset ratio is selected as 3%, the calculated roll diameter threshold is 520.15 mm. Conversely, when the verified paper tube type is equal to that of a thick paper tube, the control program enters the thick paper tube control strategy branch. Thick paper tubes, due to their stronger compressive strength, need to be emptied of strip material as much as possible to reduce material waste. Therefore, their roll diameter offset ratio is set to zero or a small negative range, between -3% and 0%. When calculated using the same formula, the resulting roll diameter threshold will be less than or equal to the inner diameter of the paper tube. For example, for the same 505 mm inner diameter, if the configured thick paper tube offset ratio is -2%, the calculated roll diameter threshold drops to 494.9 mm, thus ensuring that unnecessary premature intervention does not occur before the strip material is completely detached.

[0020] While generating the roll diameter threshold, the programmable logic controller (PLC) needs to simultaneously set the tension deviation threshold. This threshold is a crucial measure for subsequent determination of whether roll breakage or complete venting has occurred. The setting of the tension deviation threshold is also highly dependent on the differentiated characteristics of the paper roll type. For thin paper rolls, the pressure relief control action is mainly driven by the roll diameter monitoring signal. To prevent misjudgments caused by normal, minor tension fluctuations during unwinding and resulting in unexpected rapid power-off and pressure relief of the expansion cylinder, a larger tolerance is assigned to the tension deviation threshold for thin paper rolls. The specific calculation formula is as follows: ,in Represents the tension deviation threshold. The given tension target value set in the current unwinding process parameters. This is the tolerance ratio. For the thin paper tube branch, this tolerance ratio is set between 30% and 50%. If the given tension target value is 10,000 Newtons, and a tolerance ratio of 40% is selected, the final tension deviation threshold is set to 4,000 Newtons. For the thick paper tube branch, because its roll diameter threshold is set extremely close to or even lower than the physical inner diameter, the triggering mechanism at the end of unwinding relies almost entirely on the tension surge signal caused by the instant the strip leaves the paper tube. Therefore, extremely high detection sensitivity must be maintained. For the thick paper tube branch, this tolerance ratio is strictly compressed within the sensitive range of 10% to 20%. If the given tension target value is also 10,000 Newtons, and a tolerance ratio of 15% is selected, the tension deviation threshold is precisely set to 1,500 Newtons. These two core parameters are immediately stored in the controller's cache register.

[0021] Step 2: Filter the roll diameter and tension signals collected by the roll diameter and tension sensors to obtain the current roll diameter and tension. Correspondingly, in the uncoiling operation of continuous production lines such as color coating, the operation of large mechanical equipment, the high-frequency vibration of hydraulic pump stations, and the electromagnetic radiation from electrical components such as frequency converters result in a working environment filled with complex physical and electromagnetic interference. When the roll diameter and tension sensors installed on the uncoiler monitor the strip uncoiling dynamics in real time, the raw analog signals output by these sensors often contain a large amount of random high-frequency noise and transient spike interference. If these unprocessed burr signals are directly input into the programmable logic controller (PLC), misjudgments are easily triggered at the end of uncoiling, leading to unexpected decompression or cutting actions by the expansion cylinder. Therefore, introducing a step to filter the roll diameter and tension signals collected by the roll diameter and tension sensors can effectively eliminate environmental noise and electrical interference during the measurement process, restoring the true and smooth process parameters.

[0022] In one embodiment, the operational details of step 2 are as follows: First, the roll diameter detection sensor acquires the raw signal. This sensor is a non-contact laser rangefinder installed above the uncoiler side. It emits a laser beam and receives reflected light, outputting a raw roll diameter signal reflecting the change in the outer contour of the strip in the form of continuous analog voltage or current. Simultaneously, the tension detection sensor acquires the raw signal. This sensor is generally composed of a piezomagnetic or strain gauge force gauge installed below the bearing seat of the guide roller after the uncoiler. It converts the tension applied to the strip into a weak electrical signal, which is then amplified into a raw tension signal. These two continuous analog signals are transmitted in real time to the analog input module of the programmable logic controller. After high-frequency sampling by the analog-to-digital converter, they are discretized into a raw roll diameter digital sequence and a raw tension digital sequence containing discrete timestamps.

[0023] For the discretized digital sequence, the programmable logic controller (PLC)'s arithmetic unit invokes a composite digital filtering model for multi-stage smoothing. The specific architecture of this model consists of a pre-stage moving average filter and a post-stage first-order hysteresis filter connected in series. The pre-stage moving average filter aims to eliminate transient spike noise caused by sudden mechanical vibrations. Its processing logic follows a mathematical formula: In this formula, Characterizing the raw signal sequence data points acquired continuously in the present and past, This represents the preset depth of the sliding window. This represents the intermediate smoothed value output after pre-filtering. The weight bias parameters in the model are the equally distributed weight constants. This constant is directly assigned by the computational unit based on the principle of equal probability smoothing during the initialization configuration phase. Taking roll diameter signal processing as an example, if the sliding window depth is set to 10, when ten recent raw roll diameter data containing a peak value of 555.2 mm are collected, the extreme value is effectively diluted through the accumulation and averaging of these equally weighted data, and the calculated intermediate smooth value may be 551.8 mm.

[0024] The intermediate smoothed value, after pre-smoothing, then enters the first-order hysteresis filter stage. This stage architecture aims to overcome the phase delay caused by moving averages and filter out residual low-frequency random fluctuations, making the signal more closely resemble the actual physical change trend. Its operational logic follows a mathematical formula: In this formula, The current intermediate smoothing value is the input of the pre-stage. This is the final filtered output value of the previous sampling period recorded in the cache register of the arithmetic unit. This represents the final filtered output value at the current moment. This is the filter sensitivity coefficient. The value of the filter sensitivity coefficient is strictly limited to between 0 and 1, and its specific value is preset by the engineering commissioning personnel based on the response frequency of the field sensors. Continuing the calculation example of the roll diameter signal above, if the filter sensitivity coefficient for the roll diameter is set to 0.2, and the output value of the previous cycle read from the buffer is 552.0 mm, substituting it into the formula, we get 0.2 × 551.8 + 0.8 × 552.0, and the final output result is 551.96 mm. This value is then confirmed as the current roll diameter, and it is steadily approaching the roll diameter threshold of 520.15 mm or 494.9 mm set in the previous step for a paper roll with an inner diameter of 505 mm.

[0025] The filtering of the tension signal also follows the same composite digital filtering model. However, because tension is affected by strip deformation and transmission clearance, its fluctuation frequency is more drastic than that of the roll diameter, so the parameter configuration is different. The sliding window depth of the tension signal can also be set to 10. Under the condition of a given tension target value of 10000 Newtons, the original tension signal oscillates at a high frequency between 9850 Newtons and 10300 Newtons. After processing by the moving average filtering stage, the intermediate smoothed value may be 9980 Newtons. When entering the first-order hysteresis filtering stage, in order to take into account the rapid response to the situation of tension loss and strip breakage, the tension filtering sensitivity coefficient is moderately amplified and preset to 0.3. If the tension filtering output value of the previous cycle recorded in the cache is 10010 Newtons, substituting it into the formula of the same architecture for calculation, we get 0.3×9980 + 0.7×10010, and the final calculation result is 10001 Newtons. This precise and stable value is then confirmed as the current tension.

[0026] Step 3: The programmable logic controller (PLC) performs logical judgments on the current roll diameter, current tension, roll diameter threshold, and tension deviation threshold to obtain roll diameter trigger signals and tension loss trigger signals. It is understandable that during the final unwinding stage of the uncoiler operation, as the strip material is gradually consumed, the radial binding force on the paper tube weakens rapidly, posing a risk of deformation or even breakage under no-load conditions. Although previous steps have established specific safety boundaries for different types of paper tubes and obtained high-precision real-time process parameters filtered out environmental interference, these static threshold limits and dynamic monitoring data, if kept in isolation, cannot be automatically converted into effective equipment action execution commands. By introducing a PLC to logically judge the current roll diameter, current tension, roll diameter threshold, and tension deviation threshold to obtain roll diameter trigger signals and tension loss trigger signals, the dynamic monitoring data is deeply logically correlated and compared with the preset safety boundaries. Through rigorous data verification and mathematical difference calculation, the critical state of the roll diameter approaching its limit or the tension suddenly being lost is accurately captured, thereby generating a deterministic Boolean trigger signal. This provides a decisive prerequisite for subsequent output of differentiated pressure reduction or cut-off control commands.

[0027] Figure 3 This is a flowchart of step 3 in the paper tube tension control method according to an embodiment of this application. Figure 3 As shown, in one embodiment, step 3 includes: step 31, comparing and judging the current roll diameter with the roll diameter threshold, and calculating the tension deviation between the given tension and the current tension, wherein a roll diameter trigger signal is generated when the current roll diameter is less than or equal to the roll diameter threshold, and a tension loss trigger signal is generated when the tension deviation is greater than the tension deviation threshold. Specifically, in one embodiment, step 31 compares the current roll diameter with a roll diameter threshold and calculates the tension deviation between the given tension and the current tension. A roll diameter trigger signal is generated when the current roll diameter is less than or equal to the roll diameter threshold, and a tension loss trigger signal is generated when the tension deviation is greater than the tension deviation threshold. This includes: step 311, reading the given tension from the tension control system; step 312, calculating the difference between the current roll diameter and the roll diameter threshold to obtain the roll diameter difference, and determining the sign of the roll diameter difference. If the roll diameter difference is less than or equal to zero, the roll diameter comparison result is set as the trigger condition met, and a roll diameter trigger signal is generated based on the roll diameter comparison result; step 313, calculating the difference between the given tension and the current tension to obtain the tension deviation, and comparing the tension deviation with a tension deviation threshold. If the tension deviation is greater than the tension deviation threshold, a tension loss trigger signal is generated.

[0028] The relevant operational details are as follows: Step 311: First, the communication interface of the programmable logic controller (PLC) needs to read the core process parameter, the given tension, from the upper-level tension control program. The given tension is preset by the operator on the human-machine interface according to the specific material and strip thickness specifications of the steel coil to be processed, and its physical unit is uniformly Newton. For example, for a specific specification of color-coated steel coil, the operator sets the given tension to 10,000 Newtons. While acquiring this parameter, the PLC's data receiving buffer layer synchronously receives the current coil diameter and current tension output from the previous step, as well as the coil diameter threshold and tension deviation threshold generated in step 1.

[0029] Subsequently, the data enters the boundary limit comparison layer and anomaly judgment layer of the multi-dimensional data integrity check architecture. This architecture performs rigorous integrity checks on the current roll diameter, current tension, roll diameter threshold, tension deviation threshold, and given tension, focusing on checking for null values, values ​​exceeding physical limits, or garbled values ​​with abnormal formats. If any data read fails the integrity check, the anomaly judgment layer will immediately trigger a data anomaly alarm and forcibly suspend the generation process of subsequent trigger signals to prevent malfunctions caused by dirty data; if all data is confirmed to be valid values, the control program allows entry into the substantive dual-channel judgment logic execution phase.

[0030] Step 312: Assuming all data are valid values, the first channel, the volume diameter decision channel, is activated. It calculates the difference between the current volume diameter and the volume diameter threshold to obtain the volume diameter difference, and then performs a crucial sign determination on this difference. This process follows the core comparison formula: In this formula, Characterizes the difference in roll diameter obtained from the calculation. Characterizes the current volume size after filtering. This represents the preset roll diameter threshold for the current paper tube type. The programmable logic controller (PLC) arithmetic unit obtains the roll diameter difference through a subtraction operation and immediately determines its sign. If the roll diameter difference is less than or equal to zero, it indicates that the current roll diameter has physically reached or fallen below the set roll diameter threshold, and the strip material allowance is in a critical state that threatens the paper tube structure. At this time, the PLC sets the Boolean value in the roll diameter comparison result status register to the trigger condition met, and generates a roll diameter trigger signal with a true value of logic high based on this met state. Combining the data flow from the previous step, when processing thin paper tubes, the roll diameter threshold is set to 520.15 mm. As the unwinding process continues, the filtered current roll diameter continuously decreases from 551.96 mm. If the current roll diameter drops to 519.50 mm at a certain moment, the roll diameter difference calculated using the formula is -0.65 mm. Since this difference is less than zero, the roll diameter decision channel successfully captures the critical state and immediately generates a valid roll diameter trigger signal. For thick paper rolls, the roll diameter threshold is set to a low 494.9 mm. The corresponding signal will only be triggered when the current roll diameter is further reduced to this value or below.

[0031] Step 313: Simultaneously, the second channel, the tension decision channel, operates in parallel, responsible for calculating the difference between the given tension and the current tension to obtain the tension deviation, and comparing this tension deviation with the tension deviation threshold for judgment. This calculation process follows a logical judgment formula: In this formula, Characterizes the calculated tension deviation, Characterizes the given tension read from the tension control program. This represents the current tension after filtering. Because the originally taut strip relaxes instantly when it leaves the paper tube or breaks, the current tension detected by the sensor drops sharply, resulting in a large positive difference between the given tension and the current tension. The processing unit calculates the tension deviation. The tension deviation is compared to a pre-defined tension deviation threshold. If the tension deviation exceeds the threshold, it indicates a significant discrepancy between the actual and given tension, signifying complete detachment or tape breakage. In this case, the programmable logic controller (PLC) generates a high-level logic trigger signal based on the comparison result. Continuing with the parameter settings for thick paper rolls, the given tension is 10,000 Newtons, and the sensitive tension deviation threshold is 1,500 Newtons. During the smooth unwinding phase, the current tension remains around 10,001 Newtons, and the calculated tension deviation is -1 Newton, far below the 1,500 Newton threshold, remaining silent. The moment the tape completely detaches from the paper roll, the current tension rapidly drops to 500 Newtons. Substituting this into the formula, the tension deviation surges to 9,500 Newtons. This value is significantly greater than the 1,500 Newton threshold, prompting the tension decision channel to respond precisely and immediately generate a valid tension loss trigger signal.

[0032] Step 4: The programmable logic controller (PLC) performs logical judgments based on the roll diameter trigger signal, the tension loss trigger signal, and the paper tube type. When the paper tube type is thin and a roll diameter trigger signal is received, a gradual pressure reduction command is generated; when the paper tube type is thick and a tension loss trigger signal is received, an immediate cut-off command is generated, thus obtaining the control command. It should be understood that in the aforementioned processing steps, although accurate and smooth dynamic monitoring data has been acquired, and the roll diameter trigger signal and tension loss trigger signal, which indicate the critical state at the end of unwinding, have been successfully extracted, these discrete Boolean state judgments cannot directly drive the external hydraulic actuator to perform safe and reasonable physical actions. Unwinders on continuous production lines face paper tubes of different materials and structural strengths. Thin and thick paper tubes have drastically different mechanical requirements for the triggering timing, pressure relief curve, and response sequence of hydraulic pressure relief. Introducing the PLC-based logical judgment based on the roll diameter trigger signal, tension loss trigger signal, and paper tube type to obtain control commands is to achieve deep logical coupling and strategy mapping between the previously accurately calculated dynamic alarm signals and the static paper tube material properties.

[0033] Figure 4 This is a flowchart of step 4 in the paper tube tension control method according to an embodiment of this application. Figure 4As shown, in one embodiment, step 4 includes: step 41, when the verified paper tube type is equal to a thin paper tube and the verified roll diameter trigger signal is true, setting the control strategy type to a thin paper tube early pressure reduction strategy, setting the pressure reduction mode to gradual pressure reduction, and setting the execution priority to high priority; when the verified paper tube type is equal to a thick paper tube and the verified tension loss trigger signal is true, setting the control strategy type to a thick paper tube tension loss response strategy, setting the pressure reduction mode to immediate cut-off, and setting the execution priority to emergency priority, to generate the control strategy type, pressure reduction mode, and execution priority; step 42, generating corresponding control instructions according to the pressure reduction mode through a programmable logic controller; when the pressure reduction mode is gradual pressure reduction, setting the control instruction to a gradual pressure reduction instruction; when the pressure reduction mode is immediate cut-off, setting the control instruction to an immediate cut-off instruction.

[0034] The relevant operational details are as follows: First, the high-speed data bus of the programmable logic controller (PLC) receives three core variables from the output of the preceding steps and immediately initiates a strict data type and validity boundary verification mechanism. For the received roll diameter trigger signal, the controller's data verification module performs a Boolean type check to rigorously verify whether its value is exactly logically true or logically false. Continuing with the previous example, when the current roll diameter of the thin paper roll drops to 519.50 mm, the generated logical high-level truth signal, after verification, is precisely assigned to the verified roll diameter trigger signal variable in the internal register. If garbled characters or floating-point distorted data are detected during this process, verification failure will immediately trigger a signal abnormality alarm. To ensure equipment safety, the controller will force the verified roll diameter trigger signal to false. Simultaneously, the control program performs a validity check on the paper roll type parameters transferred from the previous steps, checking whether its character identifier strictly belongs to a predefined type set, which only includes thin paper rolls and thick paper rolls. If the character verification passes, the value is assigned to the verified paper tube type as is. If a communication error causes verification to fail, not only will a parameter anomaly alarm be triggered, but the verified paper tube type will also be safely rolled back and forcibly set to the default value of thick paper tube, thus forcibly adopting a more conservative anti-false trigger control strategy. In addition, for the tension loss trigger signal, the controller also performs Boolean data type and logic value range verification. As mentioned above, in the case of thick paper tube, the high-level tension loss truth value signal calculated due to the sudden drop in tension to 500 Newtons successfully passes the verification and is assigned the verified tension loss trigger signal. Any heterogeneous data will also trigger an alarm and be forcibly masked and set to a false value.

[0035] Step 41: After ensuring all input variables are purified and valid, the programmable logic controller's (PLC) core then enters the strategy mapping matrix for compound logic judgment. This matrix is ​​strictly divided into two mutually exclusive execution flows. The first execution flow is activated when the verified paper tube type is strictly equal to the thin paper tube and the verified roll diameter trigger signal is true. This means that the excess strip material on the surface of the thin paper tube, which has weaker load-bearing capacity, is approaching its critical point. To prevent physical crushing during subsequent no-load operation, the controller explicitly sets the control strategy type variable to the thin paper tube early pressure reduction strategy. To complement this strategy, its corresponding pressure reduction mode is finely assigned as a gradual pressure reduction mode, thus avoiding strip tail deviation caused by sudden pressure loss. Simultaneously, to ensure the execution weight of this action in a multi-tasking environment, its execution priority is configured as high priority. Conversely, the second execution flow is activated when the verified paper tube type is strictly equal to the thick paper tube and the verified tension loss trigger signal is true. This indicates that the outer strip of the thick paper tube, which possesses strong supporting force, has been completely depleted and has experienced a significant loss of tension. The controller quickly sets the control strategy type variable to the paper tube tension loss response strategy. For the transient impact of complete no-load operation, the only way to prevent the paper tube from further rupturing under pressure is to cut off the power source. Therefore, the pressure reduction mode is assigned to the immediate cut-off mode, and the execution priority is configured to the highest level of emergency priority. Through this meticulous logical mapping, three core state parameters—the control strategy type, the pressure reduction mode, and the execution priority—that determine the subsequent action trajectory are successfully generated, adapting to the current operating condition.

[0036] Step 42: Based on the generated state parameters, the control program enters the action parameter calculation unit and generates control commands with physical dimensions according to the determined pressure reduction mode. When the pressure reduction mode is determined to be a gradual pressure reduction, the controller initially marks the control command as a gradual pressure reduction command and starts a dedicated pressure reduction rate calculation model. This model reads the pressure reduction time constant pre-issued by the control architecture from the configuration table and performs calculations in conjunction with real-time operating conditions. Its core mathematical calculation formula is: In this formula, Characterized by the calculated rate of continuous pressure reduction, its physical unit is megapascals per second; The current pressure of the expansion cylinder is characterized by real-time reading and feedback from a high-frequency pressure sensor deployed on the hydraulic main circuit of the expansion cylinder of the uncoiler, and the unit is megapascals. This represents the aforementioned pressure reduction time constant. The pressure reduction time constant is preset by process engineers based on the inherent damping characteristics of the hydraulic circuit and the valve's flow capacity. A typical value range is 5 to 10 seconds, the purpose of which is to lengthen the pressure relief time axis to ensure a smooth pressure decrease. For example, if the current pressure feedback from the high-frequency pressure sensor indicates that the expansion cylinder pressure is as high as 12 MPa, and the pressure reduction time constant extracted from the configuration table is 8 seconds, substituting this into the division formula yields a precise pressure reduction rate of 1.5 MPa per second. Conversely, when the pressure reduction mode is determined to be immediate cut-off, the controller initially marks the control command as an immediate cut-off command. In this mode, linear time allocation is no longer performed; instead, the pressure reduction rate attached to the command is directly statically assigned to the maximum allowable discharge rate limit of the hardware valve body, representing a requirement for the hydraulic actuator to release the destructive energy accumulated in the pipeline with the most violent burst. After determining the pressure reduction rate of the command, the control program finally fine-tunes the time axis characteristics of the command based on the execution priority given by the pre-mapping unit, i.e., determines the execution delay time parameter. When the execution priority in the input conditions is identified as emergency priority, it means that this is an extreme rescue action for the thick paper tube in a state of tension loss. The controller resolutely assigns an execution delay time of 0 seconds, indicating that the control command does not accept any program queuing or buffering and requires the hardware to execute immediately after receiving it. When the execution priority is identified as high priority, this state corresponds to the early pressure reduction strategy for the thin paper tube. In order to achieve a precise time and space convergence between the strip winding and the pressure reduction, the controller assigns an execution delay time to a pre-set advance time parameter. This advance time parameter is flexibly configured by the operator in combination with the actual belt speed of the current production line, and the typical value is also in the range of 5 to 10 seconds. For example, if the advance time parameter is set to 5 seconds, the execution delay time is confirmed to be 5 seconds, so that after the command is issued, the hydraulic valve waits for 5 seconds before starting to gradually depressurize at a rate of 1.5 MPa per second.

[0037] Step 5: Based on control commands, the expansion cylinder valve is controlled by a programmable logic controller (PLC). When the control command is a gradual pressure reduction command, the expansion cylinder valve is switched to the neutral position, and the pressure in the expansion cylinder is reduced at a preset pressure reduction rate. When the control command is an immediate cut-off command, the expansion cylinder valve is de-energized, causing the pressure in the expansion cylinder to quickly return to zero. In other words, as the unwinding operation of the continuous production line nears its end, although the pre-processing stage has completed a rigorous logical mapping from physical monitoring data to control commands and clarified the pressure relief strategies, pressure reduction rates, and delay sequences for different types of paper tubes, these commands with precise timelines and action intentions still remain only at the high-speed registers and software level of the control center, and have not been translated into actual fluid dynamic changes in the hydraulic pipeline. If the high-pressure hydraulic oil accumulated inside the unwinding machine's expansion cylinder cannot be properly released through precise switching of the hardware valves, the paper tube, in a critical unloaded state, still faces the physical risk of being crushed by enormous radial stress. This invention introduces a control-command-based approach, using a programmable logic controller (PLC) to control the expansion cylinder valve. When the control command is a gradual pressure reduction command, the valve is switched to the neutral position, and the cylinder pressure is reduced at a preset rate. When the command is an immediate cut-off command, the valve is de-energized, rapidly reducing the cylinder pressure to zero. This process overcomes the final control barrier between software logic and hardware execution. By precisely parsing the command type and driving the corresponding solenoid valves and quick-release valves, abstract control parameters are transformed into substantial attenuation of hydraulic flow and pressure. This completely eliminates the destructive force of the expansion cylinder on the paper tube at the end of unwinding, thus achieving the unwinding process.

[0038] In one embodiment, step 5 includes: identifying the control command type, wherein when the control command is a gradual pressure reduction command, the parsed control command is set as a gradual pressure reduction command; when the control command is an immediate cut-off command, the parsed control command is set as an immediate cut-off command, to generate the parsed control command, target valve status, target pressure, and pressure control mode; reading the current valve status of the expansion cylinder hydraulic system through the programmable logic controller, comparing the current valve status with the target valve status to determine whether a valve switching action needs to be performed, wherein when the target valve status is the neutral pressure relief position, all coils of the expansion cylinder solenoid valve are de-energized to return the valve core to the neutral position to achieve gradual pressure relief; when the target valve status is the de-energized rapid pressure relief position, all power supplies to the expansion cylinder solenoid valve are immediately cut off and the opening signal of the rapid pressure relief valve is triggered to achieve rapid pressure relief.

[0039] The relevant operational details are as follows: First, the programmable logic controller's instruction parsing engine receives the control instruction output from the previous processing step and immediately initiates deep parsing and instruction type identification of the instruction. This parsing process aims to decompose the comprehensive control instruction into discrete action parameters that can be directly mapped to the underlying hydraulic components. When the received control instruction is identified as a progressive pressure reduction instruction in its attribute field, this state corresponds to the thin paper tube protection condition triggered when the current roll diameter drops to 519.50 mm. At this time, the instruction parsing engine strictly sets the parsed control instruction variable to a progressive pressure reduction instruction. Simultaneously, to guide the specific movement of the underlying hydraulic valve core, the target valve state parameter is precisely set to the mid-position depressurization position. For the ultimate point of pressure control, the target pressure parameter is set to 0 MPa, representing the requirement that the hydraulic pipeline ultimately completely loses tension. Furthermore, the pressure control mode parameter is set to progressive pressure reduction mode. In this way, the controller successfully generates four core state data points: the clearly parsed control instruction, the target valve state, the target pressure, and the pressure control mode, laying the data foundation for subsequent gradual pressure reduction operations. In another operating condition, when the received control command is identified as an immediate cut-off command in its attribute field, this state corresponds to the emergency rescue situation triggered by the aforementioned tension drop causing the tension deviation to surge to 9500 Newtons. Faced with this emergency, the command parsing engine also responds quickly, firmly setting the parsed control command variable to the immediate cut-off command. Because the hydraulic power source needs to be cut off with the most forceful action, the controller sets the target valve state parameter to the power-off rapid pressure relief position. Similar to the gradual pressure reduction mode, its final control extreme point is also set to the target pressure parameter at 0 MPa. To drive the subsequent large-flow oil discharge action, the pressure control mode parameter is configured to rapid pressure relief mode.

[0040] Upon entering the hardware execution layer, the programmable logic controller (PLC) first needs to understand the current physical state of the external actuator. The controller reads the current valve status from the hydraulic main circuit sensor of the expansion cylinder via the underlying communication bus. During normal strip uncoiling, to maintain stable coil rotation, the current valve status remains at the tension supply position, meaning the hydraulic pump continuously provides support pressure to the high-pressure chamber of the expansion cylinder. Subsequently, the controller's action comparison unit performs a Boolean logic comparison between the read current valve status and the target valve status generated in the previous step to determine whether a valve switching action is required. Since the current tension supply position is logically mutually exclusive with the set neutral depressurization position or power-off rapid pressure relief position, the action comparison unit explicitly determines that a valve switching action must be performed and issues an action enable signal. When the target valve status is identified as neutral depressurization, the PLC first calls the execution delay time parameter set in the previous step. As mentioned above, with a 5-second delay, the controller's internal high-precision timer begins counting down. After 5 seconds, a low-level control signal is immediately output through the digital output module. This signal directly de-energizes all the working coils of the expansion cylinder solenoid valve. After losing electromagnetic attraction, the valve core inside the solenoid valve slides smoothly and accurately stops at the middle position under the restoring force of the precision springs at both ends. At this time, the main hydraulic oil supply channel is tightly closed, and the high-pressure hydraulic oil accumulated in the expansion cylinder loses its external replenishment and can only slowly flow back to the oil tank through the internal damped return oil channel, thus achieving gradual pressure relief. This process follows the dynamic pressure decay formula. In this formula, Characterizes the current pipeline pressure as it changes dynamically over time. The initial pressure of the expansion and contraction cylinder at the moment the pressure relief action begins is characterized, as previously set at 12 MPa. Characterizes the pressure decrease rate of 1.5 MPa per second calculated in the previous step. This characterizes the time elapsed since the start of the self-unloading pressure action. Substituting the data, calculations show that the pressure will steadily decrease at the set rate. After an 8-second fluid damping release process, the pressure precisely approaches zero MPa, ensuring a smooth transition of the paper roll before the strip is completely vented, avoiding abrupt stress impacts. Conversely, when the action comparison unit identifies the target valve status as the power-off rapid pressure relief position, this condition corresponds to emergency priority, and the execution delay time set in the previous step is 0 seconds. The programmable logic controller does not wait on any time axis; the digital output module acts instantly, not only immediately cutting off the power supply to all coils of the expansion cylinder solenoid valve, forcing the main oil supply circuit to fail, but also simultaneously sending a high-level opening signal to the rapid pressure relief valve connected in parallel to the hydraulic circuit via another independent digital output channel. Upon receiving the opening signal, the rapid pressure relief valve instantly opens its large-diameter valve fully, providing a very low-resistance release shortcut for the high-pressure hydraulic oil in the expansion cylinder. In this mode, the hydraulic oil in the expansion and contraction cylinder is no longer constrained by the return oil damping, but is rapidly discharged in accordance with the maximum displacement in fluid mechanics. This causes the pressure, which is as high as 12 MPa, to drop sharply in a very short time, within milliseconds, achieving a rapid return to zero pressure. This can eliminate the risk of the thick paper tube breaking under no-load conditions at the very first moment when the tension loss signal is generated.

[0041] Specifically, during the gradual depressurization process of the uncoiler on the thin paper roll, the hydraulic system needs to smoothly guide the pressure of the expansion cylinder from a high-tension state to a zero-pressure state. However, in the actual environment of fluid transmission and mechanical control coupling, if the theoretical pressure calculation simply adopts a linear decreasing model, the resulting pressure change trajectory mathematically represents a straight line with a constant slope. This means that at the starting point of the depressurization action and the ending point of complete bottoming out, the second derivative of the pressure, i.e., the system acceleration, will undergo a rigid abrupt change. This acceleration, which tends to infinity, is very likely to trigger the water hammer effect in the hydraulic pipeline system. The resulting instantaneous high-frequency mechanical vibration will directly act on the thin paper roll in the unloaded critical state, causing microscopic tearing or even structural collapse of the paper roll. Based on this, this application uses a fifth-order polynomial to smooth the depressurization trajectory and combines it with the first-order differential feedforward of tension to construct an adaptive nonlinear model to realize the gradual depressurization process. This is to eliminate hydraulic shock through the smoothing characteristics of high-order curves and establish a flexible coupling mechanism between hydraulic stress and real-time tension of the strip. This method ensures a smooth, shock-free start and stable bottoming out of the pressure unloading process at the microscopic level. It also allows the hydraulic system to actively accelerate the release of pressure when abnormal tension loss is detected, thereby completely eliminating the damage to the paper tube caused by vibration and sudden tension changes from a physical source.

[0042] In a preferred embodiment, when the target valve is in the neutral pressure relief position, all coils of the expansion cylinder solenoid valve are de-energized to return the valve core to the neutral position to achieve gradual pressure relief. This includes: using a fifth-order polynomial to smooth the pressure reduction trajectory and combining it with tension first-order differential feedforward to construct an adaptive nonlinear model to achieve gradual pressure relief.

[0043] The implementation process of gradual depressurization, employing a fifth-order polynomial smoothing depressurization trajectory and combining it with tension first-order differential feedforward to construct an adaptive nonlinear model, involves a real-time control algorithm that progressively advances the process after the programmable logic controller (PLC) determines the control command as gradual depressurization and issues the depressurization time constant. First, the algorithm needs to construct a normalized benchmark in the time dimension. The PLC obtains the current time through the system clock and, combined with the start time recorded when the gradual depressurization action begins and the preset depressurization time constant, calculates the normalized progress of the current time within the entire depressurization cycle. This calculation follows the normalized time formula: In this formula, The normalized time is a dimensionless parameter in the range [0,1], representing the relative percentage of progress in the current pressure reduction process; it is the current real-time time. To complete the initial latching moment when the valve state switches to the neutral pressure relief position; This is the pressure reduction time constant determined in step four. Taking the processing of thin paper tubes as an example, the pressure reduction time constant is set to 8 seconds. If the current pressure reduction action has been performed for 2 seconds, the calculated normalized time progress is 0.25.

[0044] After obtaining the schedule parameters, the programmable logic controller (PLC) enters the core fifth-order polynomial mapping calculation stage to generate an ideal pressure benchmark unaffected by external disturbances. This process ensures smooth convergence of the theoretical pressure along both the first and second derivative dimensions by constructing a standardized fifth-order polynomial S-curve. The calculation of the theoretical pressure baseline value follows the mathematical formula: In this formula, Characterized by the theoretical pressure baseline value, in megapascals (MPa). The initial expansion cylinder pressure latched at the start point for executing expansion cylinder pressure control; A fifth-order smooth interpolation polynomial kernel is used. The coefficients of this polynomial kernel are obtained through rigorous solution of the boundary conditions, ensuring that the progress is met. =0 and When the pressure change rate is 1, both the rate of change and the impact rate are zero. Continuing the aforementioned data flow, if the initial expansion cylinder pressure is 12 MPa, at time 0.25, the interpolation ratio obtained by the fifth-order polynomial kernel calculation is approximately 0.1035. Substituting this into the formula, the theoretical base pressure value is calculated. It is approximately 10.758 MPa. Compared to traditional linear pressure reduction, this value decreases more slowly and smoothly in the initial stage of pressure reduction, effectively avoiding the initial shock.

[0045] To enable pressure control to sense changes in strip condition, the programmable logic controller (PLC) further incorporates a tension feedforward compensation mechanism, dynamically correcting the pressure trajectory by calculating the rate of change of the current tension. This process aims to break free from the constraints of purely time-driven control, achieving flexible pressure following the tension trend. The final dynamic theoretical pressure command value is obtained through the following composite formula: In this formula, Characterizes the dynamic theoretical pressure that is ultimately generated; This is the dynamic tension compensation coefficient, measured in megapascals per second per newton. This parameter is a positive overparameter and is preset by the process engineer based on the paper tube's sensitivity to tension fluctuations, for example, set to 0.0001. The rate of change of tension, characterized by real-time acquisition and first-order differential processing, is expressed in Newtons per second. The non-negative cutoff function in the formula... Used to enforce constraints from physical boundaries, preventing excessively large compensation terms from leading to an illegal control command of negative pressure. When the unwinding process is smooth, the rate of change of tension... Approaching zero, the final theoretical pressure closely follows a fifth-order polynomial S-curve. However, once a rapid loss of strip tension is detected during the gradual pressure reduction period, i.e., a large negative rate of tension change, the compensation term... This will result in a significant negative correction. For example, if the current strip experiences a pre-tension loss due to near-final unwinding, and the tension drops by 1,000 Newtons within 0.1 seconds, the rate of tension change is -10,000 Newtons per second. Substituting this into the formula, the compensation term produces a pressure drop of -1 MPa. At this point, even if the theoretical pressure baseline calculated based on the time schedule is 10.758 MPa, the final output dynamic theoretical pressure will be significantly lower. It will also be actively accelerated and reduced to 9.758 MPa. This adaptive nonlinear adjustment mechanism enables the hydraulic system to achieve closed-loop coordination with the mechanical traction system, ensuring a smooth overall pressure reduction trajectory while providing an instantaneous response to the microscopic collapse of the material under stress. Finally, the programmable logic controller sends this high-precision dynamic theoretical pressure value to the pressure loop controller, which, through fine-tuning the current of the solenoid valve coil or the action of the proportional relief valve, achieves real-time and precise control of the expansion cylinder pressure, completely eliminating hydraulic surge and mechanical vibration, and ensuring the integrity of the thin paper tube under complex working conditions.

[0046] In summary, the paper tube tension control method based on the embodiments of this application is explained, aiming to solve the technical problem of paper tube breakage caused by continuous pressure application of the expansion and contraction cylinder and lack of differentiated control at the end of unwinding in an uncoiler. This solution uses a programmable logic controller to pre-distinguish between thin and thick paper tubes based on their inner diameter and sets corresponding roll diameter and tension deviation thresholds. During production, the system collects and processes roll diameter and tension signals in real time, thereby accurately capturing state changes at the end of unwinding. Addressing the shortcomings of existing technologies that rely solely on continuous pressure application, this solution implements a differentiated automatic pressure relief strategy: when a thin paper tube is identified and its roll diameter shrinks to a preset threshold, the system generates a gradual pressure reduction command in advance, switching the expansion and contraction cylinder valve to the neutral position for smooth pressure relief, preventing the thin paper tube from breaking due to momentary unloading; when a thick paper tube is identified and a loss of tension signal is generated after complete unwinding, the system generates an immediate cut-off command, de-energizing the valve to quickly return the pressure to zero, thus achieving intelligent and adaptive control of the expansion and contraction cylinder pressure, effectively eliminating the risk of paper tube breakage and ensuring efficient and continuous production.

[0047] Figure 5 This is a block diagram of a paper tube tension control system according to an embodiment of this application. Figure 5 As shown, the paper tube tension control system 100 according to an embodiment of this application includes: a roll diameter threshold generation module 110, used to determine the paper tube type based on the inner diameter of the paper tube using a programmable logic controller to obtain a roll diameter threshold and set a tension deviation threshold; a signal filtering module 120, used to filter the roll diameter signal and tension signal collected by the roll diameter detection sensor and the tension detection sensor to obtain the current roll diameter and the current tension; a trigger signal generation module 130, used to perform logical judgment on the current roll diameter, the current tension, the roll diameter threshold, and the tension deviation threshold using a programmable logic controller to obtain a roll diameter trigger signal and a tension loss trigger signal; and an instruction generation module. 140 is used to make logical judgments based on the roll diameter trigger signal, the tension loss trigger signal, and the paper tube type through a programmable logic controller. When the paper tube type is a thin paper tube and the roll diameter trigger signal is received, a gradual pressure reduction command is generated. When the paper tube type is a thick paper tube and the tension loss trigger signal is received, an immediate cut-off command is generated to obtain control commands. Control module 150 is used to control the expansion cylinder valve through the programmable logic controller based on the control commands. When the control command is a gradual pressure reduction command, the expansion cylinder valve is switched to the neutral position and the expansion cylinder pressure is reduced at a preset pressure reduction rate. When the control command is an immediate cut-off command, the expansion cylinder valve is de-energized to quickly return the expansion cylinder pressure to zero.

[0048] Here, those skilled in the art will understand that the specific operations of each step in the above-described paper tube tension control system have been referenced above. Figures 1 to 3 The paper tube tension control method is described in detail in the description of the paper tube tension control method, and therefore, its repeated description will be omitted.

[0049] In the embodiments provided in this application, it should be understood that the disclosed devices / terminal equipment and methods can be implemented in other ways. For example, the device / terminal equipment embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling or direct coupling or communication connection may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0050] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0051] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0052] If the integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable storage medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, or a read-only memory (ROM). Computer-readable storage media include, but are not limited to, only memory, random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media. It should be noted that the content of the computer-readable storage medium may be appropriately added to or subtracted from the content according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable storage media may not include electrical carrier signals and telecommunication signals.

[0053] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for controlling paper tube tension, characterized in that, include: Step 1: The programmable logic controller (PLC) determines the paper tube type based on the inner diameter of the paper tube to obtain the roll diameter threshold, and sets the tension deviation threshold. Specifically, when the paper tube type is a thin paper tube, the roll diameter threshold is set to a value greater than the inner diameter of the paper tube, and when the paper tube type is a thick paper tube, the roll diameter threshold is set to a value less than or equal to the inner diameter of the paper tube. Step 2: Filter the roll diameter and tension signals collected by the roll diameter detection sensor and tension detection sensor to obtain the current roll diameter and current tension; Step 3: The programmable logic controller (PLC) performs logical judgments on the current roll diameter, current tension, roll diameter threshold, and tension deviation threshold to obtain the roll diameter trigger signal and the tension loss trigger signal. This includes: comparing the current roll diameter with the roll diameter threshold, and calculating the tension deviation between the given tension and the current tension. A roll diameter trigger signal is generated when the current roll diameter is less than or equal to the roll diameter threshold, and a tension loss trigger signal is generated when the tension deviation is greater than the tension deviation threshold. This includes: reading the given tension from the tension control system; calculating the difference between the current roll diameter and the roll diameter threshold to obtain the roll diameter difference; determining the sign of the roll diameter difference; if the roll diameter difference is less than or equal to zero, setting the roll diameter comparison result as the trigger condition satisfied; and generating the roll diameter trigger signal based on the roll diameter comparison result. Step 4: The programmable logic controller (PLC) performs logical judgment based on the roll diameter trigger signal, the tension loss trigger signal, and the paper tube type. When the paper tube type is a thin paper tube and the roll diameter trigger signal is received, a progressive pressure reduction command is generated. When the paper tube type is a thick paper tube and the tension loss trigger signal is received, an immediate cut-off command is generated to obtain control instructions. Step 5: Based on the control command, the expansion cylinder valve is controlled by the programmable logic controller. When the control command is a gradual pressure reduction command, the expansion cylinder valve is switched to the neutral position and the pressure of the expansion cylinder is reduced at a preset pressure reduction rate. When the control command is an immediate cut-off command, the expansion cylinder valve is de-energized so that the pressure of the expansion cylinder quickly returns to zero.

2. The paper tube tension control method according to claim 1, characterized in that, Step 4 includes: when the verified paper tube type is equal to the thin paper tube and the verified roll diameter trigger signal is true, setting the control strategy type to the thin paper tube early pressure reduction strategy, setting the pressure reduction mode to gradual pressure reduction, and setting the execution priority to high priority; when the verified paper tube type is equal to the thick paper tube and the verified tension loss trigger signal is true, setting the control strategy type to the thick paper tube tension loss response strategy, setting the pressure reduction mode to immediate cut-off, and setting the execution priority to emergency priority, to generate the control strategy type, pressure reduction mode, and execution priority; and generating corresponding control instructions according to the pressure reduction mode through the programmable logic controller. When the pressure reduction mode is gradual pressure reduction, the control instruction is set to the gradual pressure reduction instruction; when the pressure reduction mode is immediate cut-off, the control instruction is set to the immediate cut-off instruction.

3. The paper tube tension control method according to claim 1, characterized in that, Step 5 includes: identifying the control command type, wherein when the control command is a gradual pressure reduction command, the parsed control command is set as a gradual pressure reduction command; when the control command is an immediate cut-off command, the parsed control command is set as an immediate cut-off command, to generate the parsed control command, target valve status, target pressure, and pressure control mode; reading the current valve status of the expansion cylinder hydraulic system through the programmable logic controller, comparing the current valve status with the target valve status to determine whether a valve switching action needs to be performed, wherein when the target valve status is the neutral pressure relief position, all coils of the expansion cylinder solenoid valve are de-energized to return the valve core to the neutral position to achieve gradual pressure relief; when the target valve status is the de-energized rapid pressure relief position, all power supplies to the expansion cylinder solenoid valve are immediately cut off and the opening signal of the rapid pressure relief valve is triggered to achieve rapid pressure relief.

4. The paper tube tension control method according to claim 3, characterized in that, When the target valve is in the neutral pressure relief position, all coils of the expansion cylinder solenoid valve are de-energized to return the valve core to the neutral position to achieve gradual pressure relief. This includes: using a fifth-order polynomial to smooth the pressure reduction trajectory and combining it with tension first-order differential feedforward to construct an adaptive nonlinear model to achieve gradual pressure relief.

5. A paper tube tension control system, characterized in that, include: The roll diameter threshold generation module is used to determine the paper tube type based on the inner diameter of the paper tube by the programmable logic controller to obtain the roll diameter threshold and set the tension deviation threshold. Specifically, when the paper tube type is a thin paper tube, the roll diameter threshold is set to a value greater than the inner diameter of the paper tube, and when the paper tube type is a thick paper tube, the roll diameter threshold is set to a value less than or equal to the inner diameter of the paper tube. The signal filtering module is used to filter the roll diameter and tension signals collected by the roll diameter detection sensor and the tension detection sensor to obtain the current roll diameter and current tension. The trigger signal generation module is used to perform logical judgments on the current roll diameter, current tension, roll diameter threshold, and tension deviation threshold through a programmable logic controller to obtain a roll diameter trigger signal and a tension loss trigger signal. This includes: comparing the current roll diameter with the roll diameter threshold and calculating the tension deviation between the given tension and the current tension; generating a roll diameter trigger signal when the current roll diameter is less than or equal to the roll diameter threshold, and generating a tension loss trigger signal when the tension deviation is greater than the tension deviation threshold; reading the given tension from the tension control system; calculating the difference between the current roll diameter and the roll diameter threshold to obtain the roll diameter difference; determining the sign of the roll diameter difference; if the roll diameter difference is less than or equal to zero, setting the roll diameter comparison result as the trigger condition satisfied; and generating the roll diameter trigger signal based on the roll diameter comparison result. The instruction generation module is used to make logical judgments based on the roll diameter trigger signal, the tension loss trigger signal and the paper tube type through the programmable logic controller. When the paper tube type is a thin paper tube and the roll diameter trigger signal is received, a progressive pressure reduction instruction is generated. When the paper tube type is a thick paper tube and the tension loss trigger signal is received, an immediate cut-off instruction is generated to obtain control instructions. The control module is used to control the expansion cylinder valve through a programmable logic controller based on control commands. When the control command is a gradual pressure reduction command, the expansion cylinder valve is switched to the neutral position and the pressure of the expansion cylinder is reduced at a preset pressure reduction rate. When the control command is an immediate cut-off command, the expansion cylinder valve is de-energized so that the pressure of the expansion cylinder quickly returns to zero.

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