Rolling mill rolling thickness compensation control method based on AGC hydraulic cylinder system

Abstract

This invention belongs to the field of rolling mill thickness compensation technology, specifically disclosing a rolling mill thickness compensation control method based on an AGC hydraulic cylinder system. By dividing a continuous steel plate into independent micro-elements with time-sequence identifiers, the remaining travel distance of each micro-element from the roll gap is accurately calculated through real-time speed integration. When the rolling speed changes drastically, the actual time when each micro-element reaches the roll gap can be accurately mapped, ensuring that the triggering timing of the compensation command is precisely synchronized with the spatial position of the micro-element. Simultaneously, after identifying the micro-element of the steel plate requiring compensation, the rolling force change response of the already rolled preceding micro-element is used to predict the sudden change in rolling force caused by the current micro-element entering the roll gap. Roll gap compensation is only triggered when the predicted sudden change in rolling force occurs, achieving online verification of the effectiveness of thickness deviation disturbances and minimizing redundant adjustments and additional system disturbances caused by blind compensation.

Description

Technical Field

[0001] This invention belongs to the field of rolling mill thickness compensation technology, and specifically discloses a rolling mill thickness compensation control method based on an AGC hydraulic cylinder system. Background Technology

[0002] In steel product processing, plate rolling is one of the key processes. The thickness accuracy after rolling directly determines the product quality grade. Due to uneven incoming material thickness, locally thicker areas entering the roll gap can momentarily increase the rolling force, causing the mill to bounce and resulting in out-of-tolerance exit thickness. To suppress such disturbances, it is necessary to identify abnormal entry thickness before the steel plate enters the roll gap and adjust the roll gap in advance. To this end, the AGC system uses a thickness gauge to collect the entry thickness signal and dynamically adjusts the mill roll gap to compensate for incoming material thickness deviations, ensuring that the exit thickness remains stable within the tolerance range.

[0003] However, due to the physical installation distance between the thickness gauge at the entrance and the roll gap of the rolling mill, the measured thickness signal inevitably experiences a transmission delay. To address this issue, existing technologies have provided relevant solutions. For example, Chinese Patent Publication No. CN119525291B discloses a strip thickness control method based on thickness measurement delay compensation. This method constructs a dynamic thickness transmission model that considers the positional offset of the thickness gauge and introduces an inertial element to predict the trend of the thickness signal, thereby compensating for the measurement delay. Based on this, a feedforward term to offset the rolling force bounce effect and a proportional feedback term based on the predicted thickness deviation are fused to generate a comprehensive roll gap setting command, which drives the hydraulic servo system to perform adjustments.

[0004] However, the above-mentioned existing technologies still have the following technical problems: First, the above scheme adopts a continuous signal processing framework. When the rolling speed changes drastically, it is difficult to accurately map the moment when the steel plate reaches the roll gap at each position, which leads to a mismatch between the triggering timing of the compensation command and the actual physical position, affecting the spatiotemporal synchronization of the compensation action.

[0005] Second, the above scheme only triggers the compensation action directly based on the predicted thickness deviation, without verifying whether the thickness deviation actually causes the mill state to be abnormal. In actual production, some thickness deviations may not cause obvious thickness deviations due to factors such as mill state and material characteristics. Compensating for such deviations is not only redundant, but may also introduce new disturbances due to over-adjustment. Summary of the Invention

[0006] To solve the above-mentioned technical problems, or at least partially solve them, the present invention provides a rolling mill thickness compensation control method based on an AGC hydraulic cylinder system.

[0007] The objective of this invention can be achieved through the following technical solution: a mill rolling thickness compensation control method based on an AGC hydraulic cylinder system, comprising: real-time measurement of the thickness and running speed of the steel plate at the mill inlet, marking each thickness measurement point as a steel plate micro-element with a time sequence number, and tracking the remaining stroke of each micro-element from the roll gap.

[0008] Record any micro-element whose thickness measurement value exceeds the allowable range as a micro-element that needs compensation and record the thickness deviation. Store the micro-element number, deviation, and remaining stroke in the compensation list.

[0009] For each micro-element requiring compensation, before entering the roll gap, it is determined whether compensation is necessary based on the rolling force response of the preceding micro-element. If not, it is removed from the list of elements to be compensated.

[0010] Process each micro-element that needs compensation in the list of elements to be compensated in ascending order of remaining stroke, and determine the timing of compensation triggering based on the remaining stroke and the response delay time of the hydraulic system.

[0011] When compensation is triggered, the roll gap position adjustment amount is generated based on the thickness deviation of the micro-element to be compensated and superimposed on the roll gap set value. In each control cycle, the hydraulic cylinder is controlled by the hydraulic servo valve to perform compensation. When the compensation trigger times of multiple micro-elements to be compensated are close, spatiotemporal collaborative processing of multi-micro-element continuous compensation is performed.

[0012] Combining all the above technical solutions, the positive effects of this invention are as follows: 1. After identifying the micro-element of the steel plate that needs compensation based on the inlet thickness gauge, this invention uses the rolling force change response of the pre-rolled micro-element through the roll gap to predict the sudden change in rolling force caused by the current micro-element that needs compensation entering the roll gap. The roll gap compensation action is triggered only when the prediction causes a sudden change in rolling force, thus realizing online verification of the effectiveness of thickness deviation disturbance. This allows the thickness compensation to be based on the actual mill state response rather than simply relying on the inlet thickness deviation, and can minimize redundant adjustment and additional system disturbance caused by blind compensation.

[0013] 2. This invention divides a continuous steel plate into independent micro-elements with time sequence identifiers. By integrating the speed in real time, the remaining travel distance of each micro-element from the roll gap is accurately calculated. When the rolling speed changes drastically, the actual time when each micro-element reaches the roll gap can be accurately mapped, ensuring that the triggering time of the compensation command is precisely synchronized with the spatial position of the micro-element, thereby improving the spatiotemporal alignment accuracy of the compensation action. Attached Figure Description

[0014] The present invention will be further described with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the present invention. For those skilled in the art, other drawings can be obtained based on the following drawings without creative effort.

[0015] Figure 1This is a diagram illustrating the implementation steps of the method of the present invention.

[0016] Figure 2 This is a flowchart illustrating the process of determining the timing of compensation triggering in this invention.

[0017] Figure 3 This is a flowchart illustrating the decision-making process for spatiotemporal collaborative processing of multi-micro-element continuous compensation in this invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] See Figure 1 As shown, the present invention proposes a rolling mill thickness compensation control method based on an AGC hydraulic cylinder system, including: S1, real-time measurement of the thickness and running speed of the steel plate at the mill inlet, marking each thickness measurement point as a steel plate micro-element with a time sequence number, and tracking the remaining stroke of each micro-element from the roll gap.

[0020] In an AGC (Automatic Gain Control) system, a rolling mill typically consists of a stand, rolls, and a hydraulic pressing device. During the rolling process, the steel plate first passes through the mill entrance area and then enters the roll gap formed by the upper and lower work rolls for pressing and shaping. To achieve high-precision control of the exit thickness, it is necessary to identify any anomalies in the entrance thickness before the steel plate enters the roll gap. Therefore, a thickness gauge is usually installed on the mill entrance side to collect real-time data on the thickness distribution of the steel plate along its length.

[0021] Given the physical distance between the thickness gauge and the roll gap, simply obtaining thickness data is insufficient to determine when the steel plate at the inlet reaches the roll gap. Therefore, it is necessary to simultaneously measure the running speed of the steel plate at the inlet.

[0022] In one specific embodiment, the process of measuring the thickness and running speed of the steel plate at the mill inlet is as follows: the thickness measurement value of the steel plate along the length direction is obtained in real time using an inlet thickness gauge installed on the mill inlet side at a fixed distance in front of the roll gap centerline, and the running speed of the steel plate is obtained in real time from the encoder on the mill drive side.

[0023] Since the thickness gauge at the mill inlet collects thickness signals that vary over time, and the steel plate moves continuously during the actual rolling process, thickness feature points at different locations enter the roll gap sequentially at different times. Due to the inherent dynamic response delay of the AGC hydraulic servo system, the compensation command must be issued at a precise moment before its corresponding steel plate position reaches the roll gap to ensure that the adjustment action is synchronized with the target spatial position. If the steel plate is considered as a continuous whole, it is difficult to establish a mapping relationship between the thickness measurement moment and the subsequent roll gap action position, which can easily lead to a mismatch between the compensation command and the target physical position, resulting in incorrect compensation position or timing.

[0024] To this end, the present invention discretizes the steel plate along its length into a series of time-sequentially numbered micro-elements, each corresponding to a specific spatial segment and its thickness characteristics. This number serves as the spatiotemporal identifier of the micro-element, allowing it to be dynamically tracked during its transmission from the entry thickness measurement point to the roll gap, thus providing a spatiotemporal reference for thickness compensation.

[0025] After completing the timing marking of the steel plate micro-element, in order to accurately predict the time when it reaches the roll gap, it is necessary to track and update the remaining journey from the mill entrance to the roll gap in real time. The specific tracking process is as follows: take the installation position of the entrance thickness gauge as the origin of the spatial coordinate system, define the running direction of the steel plate as positive, and establish a one-dimensional spatial position tracking coordinate system.

[0026] The moment when the thickness gauge at the entrance measures the micro-element is taken as the starting time point for tracking. In each control cycle, the subsequent real-time running speed of the micro-element is integrated over time to calculate the cumulative displacement of each micro-element along the rolling direction since the measurement time, i.e. the displacement already traveled.

[0027] Subtracting the cumulative displacement from the fixed installation distance from the inlet thickness gauge to the center line of the roll gap yields the remaining travel distance of each micro-element from entering the roll gap at the current moment. The smaller the remaining travel distance, the closer the steel plate micro-element is to the roll gap, and correspondingly, the compensation command needs to be issued in a shorter time. Therefore, the smaller the remaining travel distance, the higher the accuracy requirement for the compensation triggering timing, and the stronger the urgency of the control response.

[0028] S2. Mark the steel plate micro-element whose thickness measurement value exceeds the allowable range as micro-element that needs to be compensated and record the thickness deviation. Store the identifier, deviation, and remaining stroke of the micro-element that needs to be compensated in the compensation pending list.

[0029] Given the non-uniform thickness of steel plates along the rolling direction, not all micro-elements require compensation control. After measuring the thickness of each steel plate micro-element at the mill inlet, a thickness deviation assessment can be conducted to screen micro-elements requiring compensation. This screening process identifies truly abnormal areas that require intervention, allowing for targeted compensation actions on these micro-elements. This avoids redundant adjustments to normal areas and enables on-demand triggering of thickness compensation.

[0030] To achieve the above solution, the following screening process for compensating micro-elements is required: determine the target thickness value and the upper limit of the allowable positive deviation and the lower limit of the negative deviation based on the current rolled product specifications. The target thickness value represents the thickness specification that the steel plate should achieve after rolling. However, due to factors such as fluctuations in material properties, the actual rolled thickness is difficult to be absolutely equal to the target value. Therefore, a certain tolerance range needs to be allowed. The upper limit of the positive deviation (maximum allowable overthickness) and the lower limit of the negative deviation (maximum allowable underthickness) together constitute the allowable tolerance range for thickness control.

[0031] The measured thickness value of each micro-element is compared with the target thickness value to calculate the thickness deviation. When the thickness deviation exceeds the upper limit of the positive deviation or is lower than the lower limit of the negative deviation, it is determined that the micro-element has a compensation requirement.

[0032] For micro-elements that are determined to require compensation, record the value and direction of their thickness deviation.

[0033] Although the selected micro-elements requiring compensation exhibit thickness deviations, not all deviations lead to out-of-tolerance exit thickness. In actual rolling, influenced by factors such as material temperature distribution and deformation resistance, some entry thickness deviations can be absorbed by the system's own dynamic characteristics, without causing significant thickness fluctuations, thus requiring no compensation. This invention recognizes that the essential driving force for compensation is not the thickness deviation itself, but whether it induces a sudden change in rolling force upon entering the roll gap. This sudden change exacerbates mill bounce, leading to uncontrolled exit thickness. Therefore, the severity of the rolling force response is the criterion for determining whether compensation should be implemented.

[0034] Based on this, the present invention introduces a prediction of the potential for rolling force disturbance caused by the micro-element to enter the roll gap before the micro-element to be compensated enters the roll gap. The compensation instruction is only retained when the prediction result indicates that there is a risk of disturbance. This realizes the pre-verification of the effectiveness of thickness deviation disturbance and effectively avoids redundant adjustment of harmless deviation.

[0035] S3. For each micro-element that needs compensation, before entering the roll gap, determine whether compensation is necessary based on the rolling force response of the preceding micro-element. If not, remove it from the list of elements to be compensated.

[0036] When predicting rolling force disturbances, considering the strong temporal continuity and process similarity of adjacent steel plate micro-elements in terms of material composition, temperature distribution, and deformation conditions, their rolling force responses to thickness deviations exhibit a certain correlation. Therefore, this invention, based on the actual rolling force changes generated by the preceding micro-elements under similar thickness deviation conditions, makes an analogous prediction of the potential sudden changes in rolling force that may be triggered when the current micro-element requiring compensation enters the roll gap. By using measured response data under similar operating conditions as a basis, the reliability of the prediction is improved, providing reliable support for determining the necessity of compensation.

[0037] The implementation process of S3 is described below with reference to a specific embodiment: S31. Divide the current steel plate into a sequence of continuously numbered micro-elements along its length. Real-time acquisition of the rolling force of each preceding micro-element before entering the roll gap and after passing through the roll gap. For each preceding micro-element, calculate the absolute difference between the rolling force at the roll gap exit and the roll gap entrance, and define the ratio of this difference to the rolling force at the entrance as the rolling force change rate. This reflects the rolling force disturbance intensity caused by factors such as thickness deviation during the rolling process. The change rate is also stored in a one-to-one correspondence with the thickness deviation of each preceding micro-element at the entrance, thus constructing a preceding micro-element response record set to provide a data basis for subsequent disturbance prediction.

[0038] S32. Since the steel plate micro-element located at the front of the rolling sequence lacks the preceding micro-element that has already been rolled, the corresponding preceding micro-element response has not yet been accumulated, resulting in insufficient sample size in the initial stage of the response record set. This makes it impossible to support the reliable operation of disturbance prediction based on statistical analogy. Therefore, by setting a minimum sample size, such as 5, when the amount of data in the response record set is less than the minimum sample size, it indicates that there is currently insufficient historical response basis for validity judgment. At this time, the micro-element that needs to be compensated is conservatively judged to have the necessity of compensation to ensure control safety. After the compensation is executed, the rolling force change rate and thickness deviation are correlated and stored in the response record set.

[0039] S33. When the amount of data in the response record set reaches the minimum number of samples, for the current micro-element to be compensated in the compensation list, its thickness deviation is obtained before it enters the roll gap. In order to predict the rolling force disturbance that the micro-element may cause, it is necessary to search for historical cases with similar thickness deviations to the current micro-element in the response record set of the preceding micro-element. That is, search for multiple preceding micro-elements whose thickness deviation difference with the current micro-element to be compensated is less than the preset tolerance range (such as ±0.02mm) as a reference micro-element set.

[0040] S34. Since the reference micro-element and the current micro-element to be compensated have a sequential relationship in the rolling sequence, under the premise of similar thickness deviation, the closer the preceding micro-element is to the current micro-element, that is, the smaller the number difference, the more similar the process environment is to the current working condition, and the higher the reference value of its rolling force response for the current disturbance prediction. Therefore, the reciprocal of the number difference between each reference micro-element and the current micro-element to be compensated is used as the weight factor of the reference micro-element. Since the reference micro-element is a historical micro-element that has been rolled, the number difference is always greater than or equal to 1, and its reciprocal, i.e. the weight, has a clear physical meaning. Subsequently, the rolling force change rate corresponding to all reference micro-elements is linearly weighted and summed, and the calculation result is used as the predicted rolling force change rate of the current micro-element to be compensated.

[0041] S35. Compare the predicted rolling force change rate with the preset mutation threshold. If the predicted value exceeds the mutation threshold, it means that the resulting mill bounce may cause the exit thickness to exceed the tolerance range, which needs to be suppressed by active roll gap compensation. At this time, the micro-element is determined to be an effective disturbance and its record is retained in the compensation list. Otherwise, the micro-element is determined to be not necessary for compensation and is removed from the compensation list.

[0042] Applying to the above implementation process, the mutation threshold mentioned in S35 is used to define whether the change in rolling force is sufficient to threaten the stability of the exit thickness. For example, the rolling process data of qualified products of the same steel grade can be analyzed, the distribution of rolling force change rate that does not lead to thickness deviation can be statistically analyzed, and the 95th percentile of the rolling force change rate can be taken as the mutation threshold.

[0043] It should be noted that when the rolling force response prediction of the preceding micro-element determines that the current micro-element does not need compensation and removes it from the list of pending executions, the monitoring of it is not terminated. After the micro-element passes through the roll gap, the actual exit thickness is detected by an exit thickness gauge; if the measured value exceeds the allowable tolerance range, secondary compensation is performed as a fault-tolerant means for misjudging the effectiveness of previous disturbances or sudden changes in operating conditions.

[0044] S4. Process each micro-element to be compensated in the list of elements to be compensated in ascending order of remaining stroke, and determine the compensation triggering time based on the remaining stroke and the hydraulic system response delay time.

[0045] After verifying the effectiveness of the aforementioned disturbances, all micro-elements retained in the compensation list are valid disturbance micro-elements that require intervention. Due to the inherent response delay of the AGC hydraulic system, if the compensation command is issued only when the micro-element reaches the roll gap, it will not take effect in a timely manner. Therefore, it is necessary to determine the compensation triggering timing in advance based on the current remaining stroke of each micro-element and its corresponding arrival time at the roll gap, combined with the response delay of the hydraulic system, to ensure that the roll gap adjustment is completed before the micro-element enters the deformation zone.

[0046] See Figure 2 As shown, in a preferred embodiment of the present invention, the compensation triggering time is determined as follows: S41, for each micro-element to be compensated in the compensation list, the remaining time for it to reach the roll gap is calculated by dividing the current remaining stroke by the current real-time speed, and the remaining time is dynamically updated.

[0047] S42. The response delay time of the hydraulic servo system from receiving the control command to the hydraulic cylinder starting to generate displacement is determined in advance through experiments. The difference between the remaining time and the response delay time is calculated as the delay time of the micro-element to be compensated.

[0048] S421. When the delay time is greater than zero, it indicates that there is still enough time for the micro-element to enter the roll gap to wait for the system response. Then, a timed task is created for the micro-element, the timed duration is set to the delay time, and the compensation command is triggered after the timed duration ends.

[0049] S422. When the waiting delay time is less than or equal to zero, it indicates that the micro-element is about to enter the roll gap. If the hydraulic system delays further, it will not be able to complete the adjustment in time. At this time, it is determined that a compensation command should be issued immediately to make the maximum use of the remaining response window.

[0050] S5. When compensation is triggered, the roll gap position adjustment amount is generated based on the thickness deviation of the micro-element to be compensated and superimposed on the roll gap set value. In each control cycle, the hydraulic cylinder is controlled by the hydraulic servo valve to perform compensation. When the compensation trigger time of multiple micro-elements to be compensated is close, spatiotemporal collaborative processing of multi-micro-element continuous compensation is performed.

[0051] The compensation control applied to the above steps is as follows: S51, read the thickness deviation of the micro-element to be compensated from the list of elements to be compensated, and determine the compensation direction according to the positive or negative sign of the thickness deviation. When the thickness deviation is positive, it means that the steel plate is too thick, and the compensation direction is to reduce the roll gap. The rolling roll is further pressed down by hydraulic pressure to increase the rolling reduction and reduce the exit thickness to the target value. When the thickness deviation is negative, it means that the steel plate is too thin, and the compensation direction is to increase the roll gap. The rolling roll is raised by hydraulic pressure to reduce the rolling reduction and make the steel plate entering the roll gap less thin, so that the exit thickness is not too thin and thus approaches the target value.

[0052] S52. Multiply the thickness deviation by the pre-calibrated compensation coefficient to calculate the hydraulic cylinder position adjustment amount.

[0053] S53. Add the calculated position adjustment amount to the current roll gap setting value to generate a new roll gap setting target value as the hydraulic cylinder position control command.

[0054] S54. Use the hydraulic cylinder position control command to send a control voltage signal to the hydraulic servo valve to drive the hydraulic cylinder piston to move to the new target position.

[0055] In the above compensation control process, the compensation coefficient represents the hydraulic cylinder displacement adjustment amount corresponding to a unit thickness deviation, which can be determined using the mill bounce equation. The specific determination process is as follows: Step 1: Establish the theoretical expression of the compensation coefficient: According to the mill bounce equation, the exit thickness... Inlet thickness Roll gap setting value The relationship between rolling force and rolling force is expressed as follows: ,in This represents the mill stiffness coefficient. Meanwhile, the workpiece plasticity equation describes the relationship between rolling force and reduction. ,in Let be the plasticity coefficient of the rolled product, reflecting the material's ability to resist deformation. Combining the two equations, we get... Therefore, it can be obtained that this is to compensate for the inlet thickness deviation. Required roll gap adjustment satisfy Therefore, the theoretical expression for the compensation coefficient is: This refers to the amount of roll gap adjustment required to compensate for unit thickness deviation.

[0056] The second step is to calibrate the parameters through experiments: A pressing test is conducted under no-load conditions on the rolling mill, gradually applying different rolling forces while simultaneously measuring the actual roll gap change. A linear regression is then performed on the rolling force versus roll gap change data; the reciprocal of the slope is the mill stiffness coefficient. Meanwhile, rolling tests were conducted under steady-state rolling conditions for typical steel grades and commonly used specifications, collecting data on inlet and outlet thicknesses and rolling forces. Calculate multiple sets of samples and take the statistical average to establish a database of plasticity coefficients of rolled pieces indexed by steel grade and specifications. Then, retrieve the plasticity coefficients of rolled pieces under the current rolling conditions based on the current steel grade and specifications.

[0057] The third step is to substitute the plasticity coefficient of the rolled piece and the stiffness coefficient of the rolling mill obtained through experiments into the theoretical expression of the compensation coefficient, so as to obtain the compensation coefficient applicable to the current rolling conditions.

[0058] In the innovative implementation of this invention, considering that there may be continuous thickness abnormality areas along the length of the steel plate, such as local wedge-shaped material unevenness, under high-speed rolling conditions, multiple micro-elements that need to be compensated may approach the roll gap in a short period of time, causing their respective compensation trigger times to be close. In this case, if compensation commands are executed independently for these micro-elements, the hydraulic servo system will face frequent superimposed control requests, which may easily lead to saturation of the actuator.

[0059] To address the aforementioned issues, this invention employs spatiotemporal collaborative processing to continuously compensate multiple micro-elements with similar compensation trigger times, ensuring continuous and stable hydraulic system operation. This approach guarantees the effectiveness of compensation while maintaining the reliability of the AGC system.

[0060] Specifically, before performing spatiotemporal collaborative processing for continuous compensation, it is necessary to first evaluate the proximity of the compensation trigger time. The specific process is as follows: real-time monitoring of the compensation trigger time of each micro-element in the list to be compensated.

[0061] When the difference between the compensation trigger times of two or more micro-elements is less than the time proximity limit, it is determined that the compensation trigger times of these micro-elements are close. The time proximity limit is used to determine the maximum allowable trigger time interval for multiple micro-elements that need to be compensated to be included in the collaborative processing. It is usually taken as 0.5 times the dominant time constant of the hydraulic servo system as the time proximity limit.

[0062] See Figure 3 As shown, when the compensation trigger times of multiple micro-elements that need compensation are close, it is further determined whether the numbers of these micro-elements are continuous in the length direction of the steel plate. This continuity reflects whether these micro-elements are closely adjacent in physical space. If so, it is determined that these micro-elements belong to the same continuous thickness anomaly section.

[0063] Scenario 1: For multiple micro-elements that need compensation and whose compensation trigger times are close and belong to the same continuous thickness anomaly section, it is equivalent to a short continuous steel plate entering the roll gap. Because they are highly concentrated in space, the corresponding thickness anomalies have local similarity.

[0064] For example, the micro-elements requiring compensation, numbered 10, 11, and 12, are spatially continuous and their compensation trigger times are close. If the position adjustment amount is calculated for each continuous micro-element, the roll gap will be adjusted to [value missing] when micro-element 10 arrives. After a very short time, the micro-element 11 reaches the roll gap, and the roll gap needs to... Adjust to A very short time later, micro-element 12 reaches the roll gap, and the roll gap needs to be readjusted. .

[0065] Such small, step-like adjustments can cause unnecessary shocks to the hydraulic system, and for continuous sections, the difference in thickness deviation between adjacent micro-elements is minimal. Therefore, such fine adjustments have very limited effect on improving the thickness accuracy of the final product.

[0066] Therefore, it is appropriate to perform compensation merging and calculate the average thickness deviation of the continuous micro-elements by arithmetic averaging to obtain the average thickness deviation that characterizes the overall thickness deviation level of the abnormal section.

[0067] The uniform position adjustment amount is calculated using a pre-calibrated compensation coefficient based on the average thickness deviation. When multiple micro-elements requiring compensation pass through the roll gap in sequence, compensation actions based on the uniform position adjustment amount are performed respectively, so that the roll gap remains stable near the same target value when the entire continuous section passes through the roll gap.

[0068] Scenario 2: When multiple micro-elements requiring compensation are determined to have similar compensation trigger times but discontinuous numbering, these micro-elements are determined to be discrete thickness anomaly points at different locations. This situation usually occurs when the rolling speed is high. Multiple micro-elements requiring compensation that are originally physically far apart are compressed on the time axis, causing their compensation trigger times to be close to each other. Although their compensation instructions are dense in time, they correspond to a long steel plate area in space. Since the thickness anomalies at different locations require different roll gap adjustments, they cannot be effectively characterized by a single average value. Therefore, they should not be merged for compensation but should be handled separately.

[0069] In response to this situation, the order in which these micro-elements pass through the roll gap is used as the node, and the corresponding position adjustment amount is calculated according to the thickness deviation of each micro-element.

[0070] To avoid the hydraulic servo system receiving multiple step position commands in a short period of time, which could cause sudden acceleration changes in the actuator and oil pressure shocks, a linear interpolation method is used to generate continuous position adjustment commands between the compensation trigger times of two adjacent micro-elements that need compensation. This allows the roll gap to smoothly transition from the adjustment amount corresponding to the current micro-element to the adjustment amount corresponding to the next micro-element.

[0071] As explained in the description of the feasibility of the above operations, the control cycle of the hydraulic servo system is typically in the millisecond range (e.g., 4–10 ms), while the time approach limit is generally taken as 0.5 times the dominant time constant of the hydraulic servo system (e.g., 10–20 ms). Therefore, even if the compensation trigger times of multiple micro-elements are close, multiple control cycles can still be accommodated between adjacent trigger times, which is sufficient to discretize the generated continuous roll gap adjustment trajectory into position increment commands for each control cycle, and output and execute them cycle by cycle, ensuring the feasibility of a smooth transition.

[0072] In one application example, the micro-elements requiring compensation, numbered 10 and 20, are spatially discontinuous, but their compensation trigger times are close and separated by two control cycles. When micro-element 10 arrives, the roll gap needs to be adjusted to... When micro-element 20 arrives, the roll gap needs to be adjusted to... .

[0073] When micro-element 10 is triggered, the roll gap adjustment is calculated, and in the subsequent first and second control cycles, based on... and Intermediate setpoints are generated through linear interpolation.

[0074] When micro-element 20 reaches the roll gap, the roll gap position transitions smoothly to... Ensure they receive accurate compensation.

[0075] The generated position adjustment command sequence is discretized into position increment commands for each control cycle, and output to the hydraulic servo system for execution cycle by cycle, ensuring that the roll gap is adjusted to its required position when each micro-element to be compensated reaches the roll gap.

[0076] It should be noted that in scenario 2, there may be micro-elements that do not require compensation between adjacent micro-elements that require compensation. Since the time these micro-elements spend passing through the roll gap is extremely short and the roll gap interpolation trajectory is continuous and smooth, their impact on the thickness of the micro-elements that do not require compensation is usually negligible. If the exit thickness of individual micro-elements exceeds the allowable range due to interpolation, it can be corrected through secondary compensation.

[0077] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, in the form of a computer program product.

[0078] Those skilled in the art will recognize that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0079] In addition, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0080] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0081] Finally, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A rolling mill thickness compensation control method based on an AGC hydraulic cylinder system, characterized in that, include: The thickness and running speed of the steel plate at the mill inlet are measured in real time. Each thickness measurement point is marked as a steel plate micro-element with a time sequence number, and the remaining travel distance of each micro-element from the roll gap is tracked. Record the micro-element whose thickness measurement value exceeds the allowable range as the micro-element that needs to be compensated and record the thickness deviation. Store the number of the micro-element that needs to be compensated, the deviation, and the remaining stroke in the list to be compensated. For each micro-element that needs compensation, before entering the roll gap, it is determined whether compensation is necessary based on the rolling force response of the preceding micro-element. If not, it is removed from the list of micro-elements to be compensated. Process each micro-element that needs to be compensated in the list of elements to be compensated in ascending order of remaining stroke, and determine the timing of compensation triggering based on the remaining stroke and the response delay time of the hydraulic system. When compensation is triggered, the roll gap position adjustment amount is generated based on the thickness deviation of the micro-element to be compensated and superimposed on the roll gap set value. In each control cycle, the hydraulic cylinder is controlled by the hydraulic servo valve to perform compensation. When the compensation trigger times of multiple micro-elements to be compensated are close, spatiotemporal collaborative processing of multi-micro-element continuous compensation is performed. The determination of whether compensation is necessary based on the rolling force response of the preceding infinitesimal element is described in the following implementation process: The current steel plate is divided into a sequence of continuously numbered micro-elements along its length. The rolling force of each preceding micro-element before entering the roll gap and after passing through the roll gap is collected in real time. The rolling force change rate is calculated and stored in a one-to-one correspondence with the thickness deviation of each preceding micro-element at the entrance side to construct a preceding micro-element response record set. When the amount of data in the response record set is less than the minimum number of samples, the micro-element that needs to be compensated is directly determined to be necessary for compensation, and after the compensation is executed, its rolling force change rate and thickness deviation are correlated and stored in the response record set. When the amount of data in the response record set reaches the minimum number of samples, for the current micro-element to be compensated in the compensation list, its thickness deviation is obtained before it enters the roll gap. Multiple preceding micro-elements whose thickness deviation difference with the current micro-element to be compensated is less than the preset tolerance range are searched in the preceding micro-element response record set as a reference micro-element set. The reciprocal of the difference between the number of each reference micro-element and the current micro-element to be compensated is used to assign weights to each reference micro-element. The rolling force change rate corresponding to each reference micro-element is linearly weighted and summed. The result is used as the predicted rolling force change rate of the current micro-element to be compensated. The predicted rate of change of rolling force is compared with a preset mutation threshold. If the predicted value exceeds the mutation threshold, the micro-element is retained in the list of micro-elements to be compensated; otherwise, the micro-element is determined to be unnecessary for compensation and is removed from the list of micro-elements to be compensated.

2. The mill rolling thickness compensation control method based on an AGC hydraulic cylinder system as described in claim 1, characterized in that: The real-time measurement of the steel plate thickness at the mill inlet and the running speed is as follows: The thickness of the steel plate along its length is measured in real time from a thickness gauge installed on the mill inlet side, while the running speed of the steel plate is measured in real time from an encoder on the mill drive side.

3. The mill rolling thickness compensation control method based on an AGC hydraulic cylinder system as described in claim 1, characterized in that: The remaining travel for tracking each micro-element gap includes the following: Using the installation position of the inlet thickness gauge as the origin of the spatial coordinate system and the running direction of the steel plate as the positive direction, a one-dimensional spatial position tracking coordinate system is established. The cumulative displacement of each micro-element along the rolling direction from the measurement moment to the current moment is calculated using time integration based on the real-time running speed. Subtract the cumulative displacement from the fixed installation distance from the inlet thickness gauge to the center line of the roll gap to obtain the remaining travel distance of each micro-element from entering the roll gap at the current moment.

4. The rolling thickness compensation control method for rolling mills based on an AGC hydraulic cylinder system as described in claim 1, characterized in that: The step of recording micro-elements whose thickness measurements exceed the allowable range as micro-elements requiring compensation and recording the thickness deviation includes the following: The target thickness value, as well as the upper limit of the allowable positive deviation and the lower limit of the negative deviation, are determined based on the current specifications of the rolled product. The measured thickness value of each micro-element is compared with the target thickness value to calculate the thickness deviation. When the thickness deviation exceeds the upper limit of the positive deviation or is lower than the lower limit of the negative deviation, it is determined that the micro-element has a compensation requirement. For micro-elements that are determined to require compensation, record the value and direction of their thickness deviation.

5. The mill rolling thickness compensation control method based on an AGC hydraulic cylinder system as described in claim 1, characterized in that: The process for determining the compensation trigger timing is as follows: For each micro-element in the compensation list, calculate its estimated remaining time to reach the roll gap based on the current remaining travel and the current real-time speed; Obtain the response delay time of the hydraulic servo system, and then calculate the difference between the remaining time and the response delay time as the delay time of the micro-element to be compensated. When the delay time is greater than zero, a timed task is created for the microelement, and the timer duration is set to the delay time. If the waiting delay time is less than or equal to zero, a compensation command will be issued immediately.

6. The mill rolling thickness compensation control method based on an AGC hydraulic cylinder system as described in claim 1, characterized in that: The compensation triggering process generates a roll gap position adjustment amount based on the thickness deviation of the micro-element to be compensated and adds it to the roll gap set value. The implementation process is as follows: Read the thickness deviation of the micro-element to be compensated from the list of elements to be compensated, and determine the compensation direction according to the positive or negative sign of the thickness deviation. When the thickness deviation is positive, the compensation direction is to reduce the roll gap, and when the thickness deviation is negative, the compensation direction is to increase the roll gap. The hydraulic cylinder position adjustment amount is calculated by multiplying the thickness deviation by a pre-calibrated compensation coefficient. The calculated position adjustment amount is added to the current roll gap setting value to generate a new roll gap setting target value as the hydraulic cylinder position control command; According to the hydraulic cylinder position control command, a control voltage signal is sent to the hydraulic servo valve to drive the hydraulic cylinder piston to move to the new target position.

7. The mill rolling thickness compensation control method based on an AGC hydraulic cylinder system as described in claim 1, characterized in that: The evaluation process for determining the proximity of the compensation trigger times of the multiple micro-elements requiring compensation is as follows: Real-time monitoring of the compensation trigger time for each micro-element in the list to be compensated; When the difference between the compensation trigger times of two or more micro-elements is less than the time proximity limit, it is determined that the compensation trigger times of these micro-elements are close.

8. The mill rolling thickness compensation control method based on an AGC hydraulic cylinder system as described in claim 7, characterized in that: The spatiotemporal collaborative processing of multi-element continuous compensation includes the following: When it is determined that the compensation trigger times of multiple micro-elements that need to be compensated are close, it is further determined whether the numbers of these micro-elements are continuous in the length direction of the steel plate. If so, it is determined that these micro-elements belong to the same continuous thickness abnormality section. For multiple micro-elements that need compensation and belong to the same continuous thickness anomaly section, the average thickness deviation is calculated by arithmetically averaging their thickness deviations. The uniform position adjustment amount is calculated using a pre-calibrated compensation coefficient based on the average thickness deviation. When multiple micro-elements requiring compensation pass through the roll gap in sequence, compensation actions based on the uniform position adjustment amount are performed respectively.

9. The mill rolling thickness compensation control method based on an AGC hydraulic cylinder system as described in claim 8, characterized in that: The spatiotemporal collaborative processing of multi-micro-element continuous compensation also includes the following: When it is determined that the compensation trigger times of multiple micro-elements that need to be compensated are close but their numbers are not consecutive, these micro-elements are determined to belong to discrete thickness anomaly points at different locations. Using the order in which these micro-elements pass through the roll gap as nodes, the corresponding position adjustment amount is calculated based on the thickness deviation of each micro-element. A linear interpolation method is used to generate continuous position adjustment commands between the compensation trigger times of two adjacent micro-elements that need to be compensated; The generated position adjustment command sequence is discretized into position increment commands for each control cycle, and output to the hydraulic servo system for execution cycle by cycle, ensuring that the roll gap is adjusted to its required position when each micro-element to be compensated reaches the roll gap.

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