阅读说明：本技术 一种钢板厚度控制方法、计算机可读介质及电子设备 (Steel plate thickness control method, computer readable medium and electronic device ) 是由 赵会平 王欣 凌鹰鹤 张文宾 郑涛 陶涛 于 2020-06-04 设计创作，主要内容包括：本发明提供了一种钢板厚度控制方法、计算机可读介质及电子设备,该钢板厚度控制方法用于多机架冷连轧机生产控制系统,包括：获取至少两组与冷连轧机生产相关的参数测量值,参数测量值包括末位机架的出口速度测量值、次末位机架的轧制力测量值,以及各机架的出口厚度测量值；判断参数测量值是否满足可信度条件,若满足可信度条件,则继续,否则,重新执行获取步骤；判断参数测量值是否满足预设条件,若满足预设条件,则继续,否则,重新执行获取步骤；根据预设算法获得多个机架的厚度控制参数。本方法能够在现有设定的基础上自动进行优化计算,实现在不破坏控制状态的情况下对模型进行动态控制,提高产品厚度的控制精度。(The invention provides a steel plate thickness control method, a computer readable medium and an electronic device, wherein the steel plate thickness control method is used for a multi-stand cold continuous rolling mill production control system and comprises the following steps: acquiring at least two groups of parameter measurement values related to the production of the cold continuous rolling mill, wherein the parameter measurement values comprise an outlet speed measurement value of a last stand, a rolling force measurement value of a next last stand and an outlet thickness measurement value of each stand; judging whether the parameter measurement value meets the reliability condition, if so, continuing, otherwise, re-executing the obtaining step; judging whether the parameter measurement value meets a preset condition, if so, continuing, otherwise, re-executing the obtaining step; and obtaining thickness control parameters of the plurality of racks according to a preset algorithm. The method can automatically perform optimization calculation on the basis of the existing setting, realize dynamic control on the model under the condition of not damaging the control state, and improve the control precision of the product thickness.)

1. A steel plate thickness control method is used for a production control system of a multi-stand cold continuous rolling mill, and is characterized by comprising the following steps:

an obtaining step, obtaining at least two groups of parameter measured values, wherein the parameter measured values comprise an outlet speed measured value of a last stand, a rolling force measured value of a second last stand and an outlet thickness measured value of each stand;

a first judgment step of judging whether the parameter measurement value meets a reliability condition, if so, continuing, otherwise, re-executing the acquisition step;

a second judgment step of judging whether the parameter measurement value meets a preset condition, if so, continuing, otherwise, re-executing the acquisition step;

and resetting, namely obtaining the thickness control parameters of all the racks according to a preset algorithm.

2. The method of claim 1, wherein the second determining step comprises:

calculating an exit velocity change rate, an average exit velocity, an average deflection deviation and an average rolling force deviation according to the exit velocity measurement value, the exit thickness measurement value and the rolling force measurement value;

analyzing whether a) the exit velocity change rate is smaller than a first threshold value, b) the average exit velocity is larger than a second threshold value, c) the average deflection deviation is larger than a third threshold value, and d) the average rolling force deviation is larger than a fourth threshold value, and if a) to d) are all yes, the preset condition is satisfied.

3. The method of claim 2, wherein the average deflection is an average of absolute values of differences between actual exit deflections of the penultimate stand and set exit deflections of the penultimate stand, and wherein the average rolling force deflection is an average of ratios of absolute values of differences between the rolling force measurements and set rolling forces to the set rolling forces.

4. The method of claim 3, wherein the actual exit distortion is satisfied

Wherein, r2_jRepresenting the actual exit deflection of the jth rack, h2_jRepresents the exit thickness measurement of the j-th stand, j ═ 1,2, … … n, n represents the total number of stands of the cold continuous rolling mill, h2₀Representing the initial thickness of the steel sheet.

5. The method according to claim 2, wherein the values of the first to fourth threshold values are related to the state of the cold continuous rolling mill, the type of the steel sheet, and production requirements.

6. The method of claim 1, wherein the first determining step comprises:

establishing a reliability function relation corresponding to the parameter measured value;

solving the reliability function relation to obtain a first reliability value, a second reliability value and a third reliability value corresponding to the outlet speed measurement value, the outlet thickness measurement value and the rolling force measurement value respectively;

and comparing the first reliability value, the second reliability value and the third reliability value with preset values respectively, and if the first to third reliability values are all larger than the preset values, meeting the reliability condition.

7. The method of claim 6, wherein the belief function relationship is

Wherein x is_iRepresents the ith said outlet speed measurement or said outlet thickness measurement or said rolling force measurement; n represents the number of the outlet speed measured value, the outlet thickness measured value or the rolling force measured value obtained in a preset period, and N is more than or equal to 2; alpha represents a credibility parameter; VI represents the confidence value.

8. The method of claim 1, wherein the thickness control parameters include an amount of outlet deformation to be set and an outlet thickness to be set.

9. The method of claim 8, wherein the resetting step comprises:

determining the deformation of an outlet to be set of the last rack according to a thickness compensation function;

determining the deformation of the outlet to be set of other racks except the last rack according to a first preset relation;

and determining the thickness of the outlet to be set of each rack according to a second preset relation.

10. The method of claim 9, wherein the thickness compensation function is

R_n＝r1_n+(r2_n-r1_n)×β (3)

Wherein R is_nRepresenting the deformation of the outlet to be set of the last stand, r1_nRepresenting the current set exit deflection of the last stand, r2_nRepresenting the actual outlet deformation of the last frame, and the value of beta is between 0.75 and 1.25.

11. The method of claim 10, wherein the first predetermined relationship is

Wherein R is_jRepresenting the deformation of an outlet to be set of the j-th rack, wherein j is 1,2, … … n-1; n represents the total number of the stands of the tandem cold rolling mill, m represents the serial number of the first stand which can be adjusted for relative deformation, r2_jRepresenting the actual exit deflection of the jth rack, h1_n-1Representing the current set exit thickness, H, of the next last stand_n-1Representing the thickness of the outlet to be set of the penultimate stand, e1_aRepresenting the current set entry thickness of the first frame, which is adjustable with respect to the amount of deformation, e2_aThe thickness of the actual inlet of the first frame which can be adjusted by relative deformation is represented, and the value of lambda is between 0.95 and 1.05.

12. The method according to claim 11, wherein the exit thickness H to be set of the penultimate rack in equation (4)_n-1The second preset relationship is satisfied.

13. The method of claim 11, wherein the first frame capable of relative deformation adjustment is a first frame, and the current set entry thickness and the actual entry thickness of the first frame are both the initial thickness of the steel plate.

14. The method of claim 9, wherein the second predetermined relationship is

Wherein H_jRepresents the outlet thickness to be set of the j-th rack, j being 1,2, … … n-1.

15. The method of claim 14, wherein the exit thickness H to be set for the last stand is_nIs the target thickness of the steel sheet.

16. The method of claim 8, wherein the thickness control parameters further comprise: the method comprises the following steps of setting a rolling force to be set, a rolling force moment to be set, power to be set and a length to be set of a wedge-shaped transition region;

the resetting step further comprises:

and determining the rolling force to be set, the rolling force moment to be set, the power to be set and the length to be set of the wedge-shaped transition region of each rack according to the thickness of the outlet to be set of each rack and the deformation of the outlet to be set.

17. The method of claim 1, further comprising:

and replacing the original set thickness control parameter with the obtained thickness control parameter, and transmitting the thickness control parameter to an L1 basic automation system.

18. The method of claim 1, prior to the obtaining step, further comprising:

and setting the thickness of the outlet and the deformation of the outlet of each frame according to experience.

19. The method of claim 1 wherein said exit velocity measurements, said rolling force measurements and said exit thickness measurements are transmitted by an L1 based automation system to an L2 model control system.

20. The method according to any one of claims 1 to 19, wherein the steel sheet thickness control method is used for obtaining a thickness control parameter for controlling the reduction distribution of each stand during a medium-high speed of the cold continuous rolling mill in a constant rolling force mode.

21. A computer-readable medium having instructions stored thereon, which when executed on a computer, cause the computer to perform the steel sheet thickness control method of any one of claims 1 to 20.

22. An electronic device, comprising:

a memory for storing instructions for execution by one or more processors of the system, an

A processor, being one of processors of a system, for performing the steel sheet thickness control method of any one of claims 1 to 20.

Technical Field

The invention relates to the field of cold continuous rolling mill process control, in particular to a steel plate thickness control method, a computer readable medium and electronic equipment.

Background

In the existing cold continuous rolling production process, two thickness control modes are generally adopted for meeting the requirement of the surface roughness of a product, namely the last stand adopts variable rolling force control or constant rolling force control. The constant rolling force control is suitable for the production requirement of the rough roller of which the surface of the product needs larger roughness, but along with the improvement of the calculation capability of the model and the calculation precision of the model, the constant rolling force control mode is favorable for the stability of the plate shape control, so that the constant rolling force control mode is also used in the production process of the smooth roller.

Although the application scenarios of the constant rolling force control mode are continuously increased, new problems correspondingly occur, for example, if the calculation of the current rolled product has a problem and exceeds the regulation and control range of the basic automation control system, the product has the situations of unstable production and thickness exceeding the tolerance range, and the current processing method is to stop the machine and readjust the process specification for calculation, thereby causing cost loss.

Disclosure of Invention

In view of the above, the present invention provides a method for controlling a thickness of a steel plate, which can gradually adjust a control target without stopping the steel plate, so as to improve the control accuracy of the thickness of the steel plate.

The invention provides a steel plate thickness control method for a multi-stand cold continuous rolling mill production control system, which comprises the following steps:

an obtaining step, obtaining at least two groups of parameter measured values related to the production of the cold continuous rolling mill, wherein the parameter measured values comprise an outlet speed measured value of a last stand, a rolling force measured value of a second last stand and an outlet thickness measured value of each stand;

a first judgment step of judging whether the parameter measurement value meets the reliability condition, if so, continuing, otherwise, re-executing the acquisition step;

a second judgment step, judging whether the parameter measurement value meets a preset condition, if so, continuing, otherwise, re-executing the acquisition step;

and a resetting step, namely obtaining the thickness control parameters of the plurality of racks according to a preset algorithm.

Further, the second judging step includes:

calculating the change rate of the outlet speed, the average deflection deviation and the average rolling force deviation according to the measured value of the outlet speed, the measured value of the outlet thickness and the measured value of the rolling force;

analyzing whether a) the change rate of the outlet speed is smaller than a first threshold value, b) whether the average outlet speed is larger than a second threshold value, c) whether the deviation of the average deformation amount is larger than a third threshold value and d) whether the deviation of the average rolling force is larger than a fourth threshold value, and if a) to d) are all yes, meeting the preset condition.

Further, the average deflection deviation is an average of absolute values of differences between the actual exit deflection of the penultimate stand and the set exit deflection of the penultimate stand, and the average rolling force deviation is an average of ratios of absolute values of differences between the measured rolling force values and the set rolling force to the set rolling force.

Further, the actual outlet deformation amount satisfies

Wherein, r2_jRepresenting the actual exit deflection of the jth rack, h2_jRepresents the exit thickness measurement for the jth stand, j ═ 1,2, … … n, n represents the total number of stands in the cold continuous rolling mill, h2₀Representing the initial thickness of the steel sheet.

Further, the values of the first to fourth threshold values are related to the state of the cold continuous rolling mill, the type of steel sheet, and the production demand.

Further, the first judging step includes:

establishing a reliability function relation corresponding to the parameter measured value;

solving a reliability function relation to obtain a first reliability value, a second reliability value and a third reliability value corresponding to the outlet speed measurement value, the outlet thickness measurement value and the rolling force measurement value respectively;

and comparing the first reliability value, the second reliability value and the third reliability value with preset values respectively, and if the first to third reliability values are all larger than the preset values, meeting the reliability condition.

Further, the credibility function is expressed as

Wherein x is_iRepresents an ith outlet velocity measurement or outlet thickness measurement or rolling force measurement; n represents the number of outlet speed measured values or outlet thickness measured values or rolling force measured values obtained in a preset period, and N is more than or equal to 2; alpha represents a credibility parameter; VI represents the confidence value.

Further, the thickness control parameter comprises the outlet deformation to be set and the outlet thickness to be set.

Further, the resetting step includes:

determining the deformation of an outlet to be set of the last rack according to the thickness compensation function;

determining the deformation of the outlet to be set of other racks except the last rack according to the first preset relation;

and determining the thickness of the outlet to be set of each rack according to the second preset relation.

Further, the thickness compensation function is

R_n＝r1_n+(r2_n-r1_n)×β (3)

Wherein R is_nRepresenting the deformation of the outlet to be set, r1, of the last stand_nRepresenting the current set exit deflection of the last stand, r2_nRepresenting the actual outlet deformation of the last frame, and the value of beta is between 0.75 and 1.25.

Further, the first predetermined relationship is

Wherein R is_jRepresenting the deformation of an outlet to be set of the j-th rack, wherein j is 1,2, … … n-1; n represents the total number of cold continuous rolling stands, m represents the serial number of the first stand which can be adjusted for relative deformation, r2_jRepresenting the actual exit deflection of the jth rack, h1_n-1Representing the current set exit thickness, H, of the next last stand_n-1Representing the thickness of the outlet to be set of the next last stand, e1_aRepresenting the current set entry thickness of the first frame, which is adjustable with respect to the amount of deformation, e2_aThe thickness of the actual inlet of the first frame which can be adjusted by relative deformation is represented, and the value of lambda is 0.95-1.05.

Further, the outlet thickness H to be set of the next last rack in the formula (4)_n-1A second predetermined relationship is satisfied.

Further, the first frame capable of adjusting the relative deformation is the first frame, and the thickness of the current set inlet of the first frame is equal to the thickness of the actual inlet, and is the initial thickness of the steel plate.

Further, the second predetermined relationship is

Wherein H_jRepresents the outlet thickness to be set of the j-th rack, j being 1,2, … … n-1.

Further, the outlet thickness H to be set of the last stand_nIs the target thickness of the steel sheet.

Further, the thickness control parameters further include: the method comprises the following steps of setting a rolling force to be set, a rolling force moment to be set, power to be set and a length to be set of a wedge-shaped transition region;

the resetting step further comprises:

and determining the rolling force to be set, the rolling force moment to be set, the power to be set and the length to be set of the wedge-shaped transition region of each rack according to the thickness and the deformation of the outlet to be set of each rack.

Further, the thickness control method further includes:

and replacing the original set thickness control parameter with the obtained thickness control parameter, and transmitting the thickness control parameter to an L1 basic automation system.

Further, before the obtaining step, the method further comprises:

and setting the thickness of the outlet and the deformation of the outlet of each frame according to experience.

Further, the exit velocity measurements, rolling force measurements, and exit thickness measurements were transmitted by the L1 basic automation system to the L2 model control system.

Further, the steel plate thickness control method is used for obtaining thickness control parameters of the cold continuous rolling mill in the middle-high speed process of the constant rolling force mode, and the thickness control parameters are used for controlling the reduction distribution of each rack.

Accordingly, the embodiment of the present invention also provides a computer-readable medium, on which instructions are stored, and when the instructions are executed on a computer, the instructions cause the computer to execute the above-mentioned steel plate thickness control method.

Correspondingly, an embodiment of the present invention further provides an electronic device, including:

a memory for storing instructions for execution by one or more processors of the system, an

And the processor is one of the processors of the system and is used for executing the steel plate thickness control method.

The technical scheme of the invention has the following beneficial effects:

the steel plate thickness control method of the invention obtains the outlet speed of the last rack, the rolling force of the next last rack and the outlet thickness of each rack in the production process by using the existing measuring instrument, automatically calculates and monitors the difference between the actual value and the set value of the parameters in the production process, thereby judging whether the production process is controllable, if the judgment index has obvious deviation, the actual production process is considered to be inconsistent with the expectation and needs to be adjusted, and then the thickness control parameters related to the press distribution of each rack are obtained through automatic calculation, so that the optimization calculation can be automatically carried out on the basis of the existing setting, the model is dynamically controlled under the condition of not damaging the control state so as to achieve the purpose of automatically optimizing the model, and the control precision of the product thickness is improved.

Drawings

Fig. 1 is a flowchart of a method for controlling a thickness of a steel plate according to an embodiment of the present invention;

FIG. 2 is a graph comparing set and actual exit thicknesses for various racks that were not set using the method provided by an embodiment of the present invention;

fig. 3 is a graph comparing the set value and the actual value of the outlet thickness of each rack set by the method provided by the embodiment of the invention.

Detailed Description

The following detailed description of embodiments of the present invention will be made with reference to the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

In the field of cold rolling, the constant rolling force control technology is mostly researched in a temper mill set, and as the production targets and the rhythms of the temper mill set and a cold continuous rolling mill set are different, the thickness precision is a very key quality index of cold-rolled strip steel, technicians invent a plurality of methods for improving the thickness control precision of the strip steel in the aspect of thickness control of the cold continuous rolling mill set. For example, in the control methods such as roll eccentricity control mentioned in patent documents US4531392A, US4580224A, and JP01162509A, the roll eccentricity is calculated by model prediction or determined by using the actual load to each stand and the fluctuation of the rolling force, so as to compensate the roll eccentricity to the corresponding control value according to the variation period, thereby maintaining the thickness of the strip at the outlet of each stand stable. For example, the roll gap position control disclosed in patent documents US4125004A and US4244025A improves the overall thickness control accuracy by performing pre-control and feedback control on the roll gap position through online measurement of the deviation between the strip inlet thickness and the strip outlet thickness. These methods are all characterized by having the control strategy implemented in the process control system L1, while the L1 control system has limitations in its turndown capability, i.e., it must be turned down within a given range of the preset values in the model L2 control system, and if the deviation between the preset values and the actual production is large, it cannot be turned down by the L1 control system.

In view of this, patent document No. CN201310315449.2 discloses a two-pass rolling method for variable thickness rolling, comprising: calculating the reduction required by the first pass and the length of each section; giving a second pass target rolling force PSET; assuming the outlet thicknesses h1_ i and h2_ i of the first pass, and calculating parameters such as rolling force, rolling power and the like required by the first pass; if the capacity of the rolling mill is exceeded, returning to reset; calculating deformation resistances KF1_ i and KF2_ i of the outlet strip of the first pass according to the outlet thickness of the first pass; calculating the rolling forces Fr1 and Fr2 required by rolling the strip from h1_ i and h2_ i to h1 and h2 in the second pass, judging whether the rolling forces are equal to the preset target rolling force of the second pass, resetting h1_ i and h2_ i if the rolling forces are not equal to the preset target rolling force of the second pass, and returning again; the corresponding outlet length is calculated. The invention is characterized in that the constant rolling force of the second pass is taken as the target, the capability of the rolling mill is fully utilized, and the largest possible rolling reduction is realized. However, if the rolling capacity of the first pass has reached the limit when the actual control process has failed to reach the set target, the control process has not been able to continue the adjustment. Therefore, the method in the patent not only has high requirements on the calculation precision of the model, but also has high requirements on the accuracy of material data.

The steel plate thickness control method provided by the embodiment of the invention considers and solves the problems that the deviation of a set value is large due to production incoming material data abnormity, production process change and model self error, not only focuses on the algorithm problem of the model, but also achieves the purpose of gradually adjusting a control target without stopping the machine by automatically optimizing the model in the L2 model control system on the premise of not changing an L1 basic automation system so as to improve the steel plate thickness control precision.

As shown in fig. 1, the method for controlling the thickness of a steel sheet according to an embodiment of the present invention includes:

and step S1, an obtaining step, wherein at least two groups of parameter measured values related to the production of the cold continuous rolling mill are obtained, and the parameter measured values comprise an outlet speed measured value of a last stand, a rolling force measured value of a next last stand and an outlet thickness measured value of each stand.

Specifically, the outlet speed measurement value, the rolling force measurement value and the outlet thickness measurement value in the same group of parameter measurement values are all obtained at the same time, the measurement frequency of the parameter measurement values of every two adjacent groups is the same, for example, the outlet speed, the rolling force and the outlet thickness can be measured at the same time interval (for example, 100ms), and the measurement values (namely, the outlet speed measurement value, the rolling force measurement value and the outlet thickness measurement value) at each time are transmitted to the L2 system through the L1 system, the L2 system stores the measurement values obtained at each time until the obtained measurement values reach a predetermined number of groups, for example, 8 groups (at this time, the outlet speed measurement value, the outlet thickness measurement value and the rolling force measurement value stored in the L2 system are all 8), and then the next step is executed. Specifically, the number of sets of parameter measurement values herein may be set accordingly based on the state of the instrument, the frequency of measurement, and experience, and when the frequency of measurement is high (e.g., each parameter measurement value is measured every several milliseconds), the number of sets of parameter measurement values may be set accordingly to a larger number of sets, and when the frequency of measurement is low (e.g., each parameter measurement value is measured every few seconds), the number of sets of parameter measurement values may be set accordingly to a smaller number. For example, when parameter measurement values are acquired every 100ms, the number of sets of parameter measurement values may be set to 8 or more in consideration of making the value of measurement value data more reasonable.

Specifically, the exit velocity of the last stand may be measured using a velocimeter installed near the last stand of the cold continuous rolling mill train, the rolling force may be measured using a manometer installed at the next last stand, and the exit thickness may be measured using a thickness gauge installed near the exit of each stand.

Step S2, a first judgment step, which is to judge whether the parameter measurement value satisfies the reliability condition, that is, whether the outlet speed measurement value, the outlet thickness measurement value, and the rolling force measurement value satisfy the reliability condition, if so, continuing, otherwise, re-executing the obtaining step.

Since the measured values of the parameters such as the measured exit velocity, the measured rolling force, and the measured exit thickness obtained in step S1 are inevitably subject to errors due to the influence of the states of the measuring instrument and the respective stands of the tandem cold rolling mill, the obtained measured values of the parameters are evaluated for reliability using the reliability condition. Taking the number of the parameter values as 8 groups as an example, respectively carrying out reliability judgment on an outlet speed measured value, a rolling force measured value and an outlet thickness measured value in the 8 groups of measured values, and if the measured values of the three parameters all meet the reliability condition, continuing to execute the next step; otherwise, the 8 sets of measured values are discarded, step S1 is executed again until a new 8 sets of measured values are obtained, and the confidence level determination is performed on the new 8 sets of measured values respectively.

Step S3, a second judgment step, which is to judge whether the measured value of the parameter meets the preset condition, that is, whether the measured value of the exit velocity, the measured value of the exit thickness, and the measured value of the rolling force meet the preset condition, if the preset condition is met, continuing, otherwise, re-executing the obtaining step.

Specifically, because of the influence of the weld joint, the defect and the equipment state, the cold continuous rolling mill has a speed increasing and decreasing state, a low speed state and a medium and high speed state in the working process, and when the cold continuous rolling mill is in the speed increasing and decreasing state and the low speed state, the production process is unstable, at this time, if the obtained parameter data is recalculated, the data obtained by calculation is unreliable, and the steel plate production is influenced, so that the parameter acquisition needs to be performed in a stable state in the high speed process in a constant rolling force mode, and specifically, whether the outlet speed measurement value of the last stand meets the preset condition can be judged to be in the medium and high speed state. In some embodiments of the invention, the cold continuous rolling unit adopts a constant rolling force mode of the last stand, so that the rolling force of the last stand is not adjustable, the problem of the thickness of a steel plate occurs, and only the rolling force of the front stand can be adjusted, therefore, the rolling force of the last stand and the rolling force of the last stand can be judged to be controllable or not, and the rolling force of the last stand and the outlet deformation of the last stand can be judged to meet the preset conditions; otherwise, the current stage process is not controllable, and the step returns to the step S1 to obtain the measured values of the parameters again.

And step S4, resetting, namely obtaining the thickness control parameters of each frame according to a preset algorithm.

Specifically, the preset algorithm may be stored in the L2 model control system, and the calculation process is performed in the L2 model control system.

The steel plate thickness control method provided by the embodiment combines the deformation deviation condition in the actual production process, performs dynamic optimization calculation on the basis of the existing model technology and control system, and can realize gradual adjustment of the control target under the condition of no shutdown, thereby realizing the improvement of the product thickness control precision.

Further, the second determination step S2 may include:

and step S21, calculating the change rate of the outlet speed, the average deformation deviation and the average rolling force deviation according to the measured value of the outlet speed, the measured value of the outlet thickness and the measured value of the rolling force.

Step S22, analyzing whether a) the exit velocity change rate is smaller than a first threshold, b) the average exit velocity is larger than a second threshold, c) the average deflection deviation is larger than a third threshold, and d) the average rolling force deviation is larger than a fourth threshold, and if a) to d) are all yes, determining that the preset condition is satisfied.

Specifically, the first to fourth thresholds may be stored in the L2 model control system. Because the data required for calculating the thickness control parameter in the thickness control method of the present invention needs to be data acquired in a steady state, it can be determined whether the current stage of the production process is in a velocity steady state according to the exit velocity change rate, and if the exit velocity change rate is smaller than the first threshold, the current stage of the production process is considered to be in the velocity steady state. Accordingly, as mentioned above, the comparison between the outlet speed and the second threshold may be used to determine whether the current stage is in the medium-high speed state, because there are multiple sets of outlet speed measurement values, which are affected by the instrument, and the measured data may fluctuate, therefore, in order to eliminate the error caused by fluctuation, the average outlet speed needs to be compared with the second threshold after averaging the outlet speed. Correspondingly, in order to eliminate the influence of the measuring instrument on the rolling force measured value and the outlet thickness measured value, the deflection deviation and the rolling force deviation are respectively averaged and then respectively compared with a third threshold value and a fourth threshold value.

It is to be noted that the preset condition is satisfied only when the above four conditions, i.e., a) to d), are satisfied, and if there is only one of the conditions that is not satisfied, the preset condition is considered to be not satisfied. Taking the first threshold value of 1.2%, the second threshold value of 500m/min, the third threshold value of 15%, and the fourth threshold value of 15% as an example, if the exit speed variation rate is 1.3%, the average exit speed is 550m/min, the average deformation deviation is 17%, and the average rolling force deviation is 17%, the conditions b) to d) are satisfied for the average exit speed, the average deformation deviation, and the average rolling force deviation, but since the exit speed variation rate is greater than the first threshold value, the condition a) is not satisfied, and it is considered that the preset condition is not satisfied, and the process returns to step S1 to re-acquire the parameter measurement value.

In particular, the values of the first to fourth threshold values are related to the state of the cold continuous rolling mill train, the type of steel sheet to be rolled and the production requirements.

Further, the average deflection deviation is an average of absolute values of differences between the actual exit deflection of the penultimate stand and the set exit deflection of the penultimate stand, and the average rolling force deviation is an average of ratios of absolute values of differences between the measured rolling force values and the set rolling force to the set rolling force.

The calculation formula of the average deformation deviation is as follows:

wherein N represents the number of sets of the parameter measurement values acquired in step S1,represents the mean deflection deviation of the jth frame, r2_jiRepresenting the exit deflection of the jth frame corresponding to the ith thickness measurement, r1_jRepresenting the current set outlet deformation of the jth machine frame.

The calculation formula of the average rolling force deviation is as follows:

where P represents the measured value of the rolling force of the i-th last stand acquired in step S1, and P represents the current set rolling force of the last stand.

Further, the actual outlet deformation satisfies the relation:

wherein, r2_jRepresenting the actual exit deflection of the jth rack, h2_jRepresents the exit thickness measurement for the jth stand, j ═ 1,2, … … n, n represents the total number of cold continuous rolling stands, h2₀Representing the initial thickness of the steel sheet.

Further, the first determination step S1 may include:

and step S11, establishing a reliability function relation corresponding to the outlet speed measured value, the outlet thickness measured value and the rolling force measured value. Specifically, the reliability function relationship is:

wherein x is_iRepresents an ith outlet velocity measurement or outlet thickness measurement or rolling force measurement; n represents the number of sets of parameter measurements taken in step S1, i.e., the exit velocity measurements taken over a predetermined periodOr the number of the outlet thickness measured values or the rolling force measured values, wherein N is more than or equal to 2; alpha represents a credibility parameter; VI represents the confidence value.

Step S12, solving a reliability function relation to obtain reliability values corresponding to the outlet speed measurement value, the outlet thickness measurement value and the rolling force measurement value;

and step S13, comparing the reliability value with a preset value, and if the reliability value is greater than the preset value, meeting the reliability condition. Alternatively, the preset value may be determined according to the state of the cold continuous rolling mill train, the actual production demand, and the composition of the parameter measurement values, for example, when N is 8, the preset value may be set to 95%.

Further, the thickness control parameter calculated in step S1 may include the outlet deformation amount to be set and the outlet thickness to be set.

Accordingly, the resetting step S4 may include:

and step S41, determining the deformation of the outlet to be set of the last frame according to the thickness compensation function. Specifically, the thickness compensation function relationship is as follows:

R_n＝r1_n+(r2_n-r1_n)×β (3)

wherein R is_nRepresenting the amount of deformation to be set of the last stand, r1_nRepresenting the current set exit deflection of the last stand, r2_nRepresenting the actual outlet deformation of the last frame, and the value of beta is between 0.75 and 1.25.

And step S42, determining the outlet deformation to be set of other racks except the last rack according to the first preset relation. Specifically, the first predetermined relationship is

Wherein R is_jRepresenting the deformation of an outlet to be set of the j-th rack, wherein j is 1,2, … … n-1; n represents the total number of cold continuous rolling mill stands, m represents the serial number of the first stand which can be adjusted in relative deformation, h1_n-1Representing the current setting out of the next last rackMouth thickness, H_n-1Representing the thickness of the outlet to be set of the next last stand, h1_aRepresenting the current set entry thickness of the first frame, which is adjustable with respect to the amount of deformation, h2_aThe thickness of the actual inlet of the first frame which can be adjusted by relative deformation is represented, and the value of lambda is 0.95-1.05. It is noted that the set inlet thickness of the j +1 th rack is the same as the set outlet thickness of the j th rack; the actual inlet thickness of the j +1 th rack is the same as the actual outlet thickness of the j rack; the set inlet thickness and the actual inlet thickness of the first machine frame are the same and equal to the initial thickness of the steel plate to be rolled; and the thickness of the current set outlet of the last stand is the same as the thickness of the outlet to be set, and the thicknesses are both the target thickness of the steel plate to be rolled, so that if the thickness of the inlet to be set of the first stand is not equal to the initial thickness of the steel plate obtained by calculation through the second preset relation, the calculated thickness of the inlet to be set of the first stand is corrected, and the calculated thickness is replaced by the initial thickness of the steel plate. In the embodiment of the present invention, the first frame capable of adjusting the relative deformation amount may be the first frame.

And step S43, determining the thickness of the outlet to be set of each rack according to the second preset relation. Specifically, the second predetermined relationship is:

wherein H_jRepresents the outlet thickness to be set of the j-th rack, j being 1,2, … … n-1.

Notably, H in the formula (4)_n-1The above second preset relationship is also satisfied.

Further, the thickness control parameters calculated in the resetting step S4 may further include a rolling force to be set, a rolling force moment to be set, a power to be set, and a length to be set of the wedge transition region;

the resetting step S4 may further include:

according to the outlet thickness H to be set for each frame_jAnd the deformation of the outlet to be setR_jAnd determining the rolling force to be set, the rolling force moment to be set, the power to be set and the length to be set of the wedge-shaped transition region of each rack. Specifically, the wedge switching calculation formula of the wedge transition region is as follows:

L_max＝D×α×β (7)

wherein D represents the distance between the last rack and the next last rack, H_jRepresents the exit thickness to be set, H, of the jth rack calculated in the resetting step S4_nThe outlet thickness to be set of the last stand obtained by calculation in the resetting step S4 is represented, alpha is an extension coefficient and is generally 3.5-5.5, and specific data can be set according to adjustment of a rolling mill control system.

Specifically, the current set outlet thickness and the current set outlet deformation amount of each rack may be empirically set in the L2 model control system before the obtaining step S1.

Further, after step S4, the thickness control method may further include:

and S5, replacing the thickness control parameter obtained in the step S4 with the original set thickness control parameter, and transmitting the thickness control parameter obtained in the step S4 to the L1 basic automatic system to distribute the rolling reduction of each frame.

Specifically, the measured values of the parameters such as the measured value of the exit velocity, the measured value of the rolling force, and the measured value of the exit thickness obtained in step S1 are transmitted to the L2 model control system by the L1 basic automation system, and the determination process and the calculation process in step S2, step S3, and step S4 are performed in the L2 model control system. Due to the influence of subjective factors such as experience and objective factors such as instrument states, the set thickness control parameter value originally set in the system may be inaccurate, which causes errors in the production process and causes the actual thickness of the steel plate to be inconsistent with the target thickness, so that the thickness control parameter needs to be recalculated by using a preset algorithm stored in an L2 model control system, and then the calculated thickness control parameter related to the press distribution is transmitted to an L1 basic automation system through an L2 model control system to perform press distribution regulation of each rack, thereby ensuring the stability and accuracy of the steel plate production process.

Specifically, as described above, in the production process of the tandem cold mill, due to the influence of the weld, the defect, and the equipment state, the unit may perform the speed up-down, low-speed, and stable medium-high speed production, and in the normal medium-high speed production, the rolling state is more stable, and in the low-speed and speed up-down processes, the rolling state may fluctuate to some extent, so optionally, the steel plate thickness control method may be used to obtain the thickness control parameter of the tandem cold mill in the medium-high speed process of the constant rolling force mode, and the thickness control parameter is used to control the reduction distribution of each stand.

Referring to fig. 2 and 3, taking a cold continuous rolling mill with 5 stands as an example, the abscissa represents the serial number of the stand, and the ordinate represents the specific value of the outlet thickness, it can be seen from the figures that after the thickness control method provided by the present invention is used to set the outlet thickness to be set of each stand, the deviation between the outlet thickness to be set and the actual outlet thickness is significantly smaller than the deviation between the outlet thickness set value and the actual outlet thickness which are not set by the method, therefore, the thickness control method of the present invention can more effectively ensure the stability and accuracy of the steel plate production process.

The following describes the production process of a certain strip steel in a five-stand cold continuous rolling mill as an example.

Strip steel data: steel grade A, inlet thickness 3.52mm, outlet thickness 1.0mm, width 1253 mm.

The calculated strip steel thickness set value under certain process distribution is as follows:

	no. 1 rack	No. 2 rack	No. 3 rack	No. 4 rack	No. 5 rack
						Set value	2.55	1.763	1.284	1.002	1.00
Actual value	2.493	1.761	1.273	1.055	0.981
						Deviation value	-0.057	-0.002	-0.011	0.053	-0.019
Set the amount of deformation	0.275	0.309	0.272	0.22	0.002
						Actual amount of deformation	0.292	0.294	0.277	0.171	0.07

It can be seen that the set value deviates particularly greatly from the actual value.

The first embodiment is as follows: the coefficient β is 0.75, α is 5, and λ is 1.0, and the deformation correction amount and the wedge value are calculated:

thickness compensation calculation of constant rolling force stand:

R₅＝0.002+(0.07-0.002)*0.75＝0.053

inlet thickness of constant rolling force stand (5 th stand) (i.e. outlet thickness of 4 th stand) calculation:

wherein E is_jThe thickness of the inlet to be set of the j-th machine frame is the same as that of the outlet to be set of the j-1 th machine frame.

And (3) calculating the deformation compensation of other frames:

R₁＝r2₁*0.987＝0.292*0.987＝0.288

R₂＝r2₂*0.987＝0.294*0.987＝0.29

R₃＝r2₃*0.987＝0.277*0.987＝0.273

R₄＝r2₄*0.987＝0.171*0.987＝0.169

entrance thickness calculations for the other racks, calculated from back to front:

correcting the thickness of the entrance of the frame:

E₁＝3.52

calculating the switching wedge between two different set values

L_max＝4.5*5*0.75＝16.88

Example two: the coefficient β is 1.05, α is 4.5, and λ is 1.0, and the deformation correction amount and the wedge value are calculated: thickness compensation calculation of constant rolling force stand:

R₅＝0.002+(0.07-0.002)*1.05＝0.073

inlet thickness calculation for constant roll force stands:

and (3) calculating the deformation compensation of other frames:

R₁＝r2₁*0.982＝0.292*0.982＝0.287

R₂＝r2₂*0.982＝0.294*0.982＝0.289

R₃＝r2₃*0.982＝0.277*0.982＝0.272

R₄＝r2₄*0.982＝0.171*0.982＝0.168

entrance thickness calculations for the other racks, calculated from back to front:

correcting the thickness of the entrance of the frame:

E₁＝3.52

calculating the switching wedge between two different set values

L_max＝4.5*4.5*1.05＝21.26

The steel plate thickness control method provided by the invention has the advantages that under the condition that the thickness control of the cold continuous rolling mill has deviation or the rolling state is unstable, the cold continuous rolling mill can be operated without stopping, the optimization control of the rolling process is automatically carried out, the judgment of the current production state is realized, the condition whether the set value needs to be optimized and calculated is obtained, a new set value is obtained by calculation according to the actual rolling state, and then the new set value is sent to the L1 basic automation system for adjustment, so that the production process is more stable and controllable, the stability of the production process is improved, and the control precision of the product thickness is improved.

Accordingly, the present invention also provides a computer-readable medium having instructions stored thereon, which when executed on a computer, cause the computer to perform a steel plate thickness control method.

Accordingly, the present invention also provides an electronic device, comprising:

a memory for storing instructions for execution by one or more processors of the system, an

And a processor, which is one of the processors of the system, for executing the steel plate thickness control method.

The foregoing is a preferred embodiment of the present invention, and it should be noted that it would be apparent to those skilled in the art that various modifications and enhancements can be made without departing from the principles of the invention, and such modifications and enhancements are also considered to be within the scope of the invention.