A method for controlling plate thickness, primary plate shape and secondary plate shape based on an influence matrix

Abstract

The application provides a strip plate shape and thickness comprehensive control method. The method comprehensively considers the influence of the reduction adjustment, the roll inclination adjustment and the roll bending adjustment on the plate thickness, the primary plate shape and the secondary plate shape. By changing the reduction amount, the roll inclination amount and the roll bending amount respectively, the corresponding plate thickness, primary plate shape and secondary plate shape change amount is calculated, the influence coefficient of the reduction adjustment, the roll inclination adjustment and the roll bending adjustment on the plate thickness, the primary plate shape and the secondary plate shape is obtained, the influence matrix is formed, then the influence matrix is inverted to obtain the control matrix, when the plate thickness, the primary plate shape and the secondary plate shape produce deviation, the reduction, the roll inclination and the roll bending adjustment amount can be quickly calculated according to the control matrix, so that the plate thickness precision and the plate shape quality are good. The advantage of the application is that the three control means of the reduction, the roll inclination and the roll bending are closely matched, the plate thickness, the primary plate shape and the secondary plate shape deviation can be eliminated simultaneously without introducing a complex decoupling link, the control speed is fast and the precision is high.

Description

Technical Field

[0001] This invention relates to a comprehensive control technology for strip rolling shape and thickness, and particularly to a comprehensive control method for strip thickness, primary shape and secondary shape based on an influence matrix. Background Technology

[0002] Cold-rolled strip is a high-end product, widely used in the automotive, home appliance, construction, and electronics industries due to its significant advantages of high performance and high precision. With the continuous advancement of science and technology and the rapid development of modern industrial technology, the quality requirements for strip are also increasing. Strip shape and thickness are the two most important quality indicators of strip, and currently, AGC and AFC technologies are commonly used to control strip thickness and shape separately. However, shape control and thickness control are interdependent. Adjusting the thickness indirectly changes the strip shape by altering the rolling force; conversely, adjusting the shape indirectly changes the thickness by altering the bending roll force. Therefore, only by comprehensively controlling both thickness and shape can the quality of both be guaranteed simultaneously.

[0003] To date, a great deal of research has been conducted both domestically and internationally on the comprehensive control technology of strip shape and thickness in the strip rolling process. For example, Yang Jingming, Zhang Linhao, Che Haijun and Du Peng published "Comprehensive Control of Strip Shape and Thickness Based on MMAS-PID" (Rolling Steel, 2009, 26(4): 45-49); Wang Li, Wang Xuexiu and Ma Yun published "Distributed Decoupled PID Control of Strip Shape and Thickness Based on IGA Neural Network" (Computer Simulation, 2003, 20(12): 82-85); Peng Peng and Yang Quan published "Comprehensive Decoupled Control System for Strip Shape and Thickness of Cold Rolling Mill" (Iron and Steel, 2007, 42(8): 52-55). All of the above-mentioned literature introduces a decoupling compensation link to offset the mutual influence between plate shape and plate thickness control, thereby turning plate shape control and plate thickness control into two separate systems, and then using PID to control each system. The process of introducing the decoupling link is complex, and the final PID control requires optimization and tuning of the PID constant. Moreover, the control response time is not only determined by the time constant of the control device itself, but also by the PID constant, resulting in a slow response time.

[0004] In addition, the "Online Coordination Control Method for Plate Shape and Thickness of Hot Continuous Rolling Mill" (Invention Patent, Application Publication No.: CN10189043A) applied for by Zhang Xiaoping, Zhang Jinzhi, Sun Bao, Zhi Changjian and Du Xiaozhong achieves control of the convexity of the finished plate stand by changing the reduction amount of each stand of the continuous rolling mill, but this method cannot achieve quantitative control of the plate shape;

[0005] The invention patent (application publication number: CN102641897A) proposed by Xie Xiangpeng, Zhao Jing, Wu Yousheng, and Zhu Bingquan, entitled "A Comprehensive Control Method for Cold-Rolled Strip Shape and Thickness", eliminates the adverse effects of bending roll force adjustment on thickness control by calculating the thickness deviation caused by bending roll force and sending it to the thickness control system. However, this method only considers the unidirectional effect of bending roll force on thickness control and does not consider the influence of the change in pressing amount on the shape during thickness adjustment. Therefore, it cannot achieve the optimal control effect of both shape and thickness at the same time. Summary of the Invention

[0006] The purpose of this invention is to provide a comprehensive control method for plate thickness, primary plate shape, and secondary plate shape based on an influence matrix. This method can fully consider the influence of three control methods—pressure adjustment, tilting roll adjustment, and bending roll adjustment—on plate thickness, primary plate shape, and secondary plate shape, respectively. It enables the three control methods to effectively cooperate with each other, so that plate thickness, primary plate shape, and secondary plate shape can simultaneously achieve optimal control effects, thereby improving the plate thickness and plate shape quality of strip products.

[0007] The technical solution adopted in this invention is: a comprehensive control method for plate thickness, primary plate shape, and secondary plate shape based on an influence matrix, comprising the following steps:

[0008] a. The generation of the influence matrix includes the following steps:

[0009] a1. Collect rolling mill parameters, including current coil and strip rolling process parameter settings and plate thickness and shape control parameter settings. The rolling mill parameters include: work roll body length L. w Support roller body length L b Working roll diameter D w Support roller diameter D b Support roller neck diameter D bn The distance between the work roll bending cylinders is L1, the center distance between the pressing cylinders is L3, and the work roll type is C. w Support roller type C b The stiffness of a single archway is N; the rolling process parameters include: incoming material width B, incoming material thickness h0, coefficient of friction μ, and deformation resistance σ. s Front tension σ1, rear tension σ0; plate thickness and shape control parameter settings include: unloaded roll gap x1, roll tilting amount x2, and roll bending force x3;

[0010] a2. Based on the basic rolling theory, the exit thickness a1, primary plate shape a2, and secondary plate shape a3 can be expressed as the following functions:

[0011]

[0012] in: That is, all rolling mill parameters,

[0013] That is, all rolling process parameters;

[0014] The above function can be used to efficiently and quickly generate the comprehensive influence matrix for plate thickness and shape control. This function is a prediction function for exit thickness a1, primary shape a2, and secondary shape a3, when all rolling mill parameters are... and all rolling process parameters Once determined, individually changing the values ​​of the plate thickness and shape control parameters x1, x2, and x3 will yield the influence coefficients of these parameters on the exit thickness a1, primary plate shape a2, and secondary plate shape a3, respectively. Combining these nine influence coefficients will then produce the influence matrix. The specific steps include:

[0015] a21. Using the parameters given in a1 as input parameters, calculate the exit thickness based on the basic rolling theory. Primary plate shape With secondary plate shape

[0016] a22. Let x1 = x1 + Δx1, and calculate the exit thickness at this point according to the basic rolling theory. Primary plate shape With secondary plate shape

[0017] a23, Order The influence coefficient of the pressing adjustment method on the plate thickness is obtained. Influence coefficient on primary plate shape and the influence coefficient on the secondary plate shape

[0018] a24. Let x2 = x2 + Δx2, x1 = x1 - Δx1, calculate the exit thickness at this point based on basic rolling theory. Primary plate shape With secondary plate shape

[0019] a25, Order The influence coefficient of the tilting roller adjustment method on the plate thickness is obtained. Influence coefficient on primary plate shape and the influence coefficient on the secondary plate shape

[0020] a26. Let x3 = x3 + Δx3, x2 = x2 - Δx2, calculate the exit thickness at this point based on basic rolling theory. Primary plate shape With secondary plate shape

[0021] a27, Order The influence coefficient of the bending roller adjustment method on the plate thickness was obtained. Influence coefficient on primary plate shape and the influence coefficient on the secondary plate shape

[0022] a28. Construct an influence matrix from the obtained influence coefficients. Solve for the inverse matrix C of the influence matrix C. -1 .

[0023] b. Based on the influence matrix, the plate thickness, primary plate shape, and secondary plate shape are comprehensively controlled to obtain the adjustment vector ΔX of the pressing amount, tilting amount, and bending force. a Its advantage is that it allows for the simultaneous optimization of plate shape and thickness without the need for complex decoupling processes. Specifically, it includes the following steps:

[0024] b1. Collect the current thickness deviation Δa of the coiled strip. 1a First plate shape deviation Δa 2a With secondary plate shape deviation Δa 3a ;

[0025] b2. The plate thickness deviation Δa 1a 1. Primary plate shape deviation Δa 2a With secondary plate shape deviation Δa 3a Combine to form a deviation vector

[0026] b3. The C obtained in step a28 -1 With deviation vector ΔA a Multiplying these values ​​and taking the negative value yields the adjustment vectors for the reduction, tilting, and bending forces.

[0027] c. Adjust the vector ΔX of the reduction amount, the tilting amount, and the bending force. a When distributed to actual production equipment, deviations in plate thickness, primary plate shape, and secondary plate shape can be eliminated simultaneously.

[0028] The beneficial effects of this invention are: it fully considers the effects of pressure adjustment, tilting roller adjustment and bending roller adjustment on plate thickness, primary plate shape and secondary plate shape respectively, so that the three control methods work closely together, and can simultaneously eliminate the deviations of plate thickness, primary plate shape and secondary plate shape without introducing complex decoupling links, resulting in fast control speed and high precision. Attached Figure Description

[0029] Figure 1 This is a flowchart of the present invention.

[0030] Figure 2 This is a control principle diagram of the present invention.

[0031] Figure 3 This diagram illustrates the control effect of the present invention on the deviation of the output plate thickness caused by the fluctuation of the incoming material thickness.

[0032] Figure 4 This diagram illustrates the control effect of the present invention on the secondary plate shape deviation caused by the fluctuation of incoming material thickness.

[0033] Figure 5 This diagram illustrates the control effect of the incoming material crown fluctuation on the thickness deviation of the output plate in an embodiment of the present invention.

[0034] Figure 6 This diagram illustrates the control effect of the present invention on the secondary plate shape deviation caused by the fluctuation of the incoming material crown.

[0035] Figure 7 This diagram illustrates the control effect of the wedge-shaped fluctuation of incoming material on the primary plate shape deviation in an embodiment of the present invention. Detailed Implementation

[0036] The present invention will be further described below with reference to the accompanying drawings and specific examples. Taking a four-roll mill as an example, the mill equipment and process parameters are shown in Table 1. This mill is a rollless type.

[0037] Table 1

[0038]

[0039] As attached Figure 1 The steps shown are used to obtain the influence coefficient c of the pressing adjustment on the plate thickness. 11 = -0.30675, the influence coefficient c of the pressing adjustment on the primary plate shape 21 =3.4578×10 -6 MPa / mm, coefficient of influence of pressure adjustment on secondary plate shape c 31 = -43.2589 MPa / mm, the coefficient of influence of tilting roller adjustment on exit thickness c 12 =4.52264×10 -7 The influence coefficient c of tilting roller adjustment on primary plate shape 22 =282.402MPa / mm, the influence coefficient c of tilting roller adjustment on secondary plate shape 32 =8.16471×10 -5 MPa / mm, coefficient of influence of bending roller adjustment on exit thickness c 13 =0.00014046mm / kN, the influence coefficient c of bending roller adjustment on the primary plate shape 23 = -6.18176 × 10 -10 MPa / kN, coefficient of influence of bending roller adjustment on secondary plate shape c 33 = 0.216906 MPa / kN.

[0040] The established influence matrix C is:

[0041]

[0042] The obtained inverse matrix C -1 for:

[0043]

[0044] According to the appendix Figure 2 The principle shown is used to adjust the deviation of plate shape and thickness.

[0045] When the incoming material thickness suddenly changes to 0.04265mm, the resulting sheet shape and thickness deviation matrix is ​​as follows:

[0046]

[0047] Therefore, the corresponding adjustment amount required to offset the adverse effects of this sudden change on the plate shape and thickness can be calculated as follows:

[0048]

[0049] Figure 3 , Figure 4 As shown in the adjustment diagram, it can be seen that the adverse effects of this sudden change can be eliminated by adjusting the pressing and bending rollers.

[0050] When the sudden change in the incoming material crown is 0.04265mm, the resulting deviation matrix for plate shape and thickness is:

[0051]

[0052] Therefore, the corresponding adjustment amount required to offset the adverse effects of this sudden change on the plate shape and thickness can be calculated as follows:

[0053]

[0054] Figure 5 , Figure 6 As shown in the adjustment diagram, it can be seen that the adverse effects of this fluctuation can be eliminated by adjusting the bending roller more significantly and by adjusting the pressing down appropriately.

[0055] When the sudden change in the incoming material wedge shape is 0.01mm, the resulting deviation matrix for plate shape and thickness is:

[0056]

[0057] Therefore, the corresponding adjustment amount required to offset the adverse effects of this sudden change on the plate shape and thickness can be calculated as follows:

[0058]

[0059] Figure 7The diagram shows the effect of the adjustment. It can be seen that to eliminate the influence of fluctuations, the tilting rollers need to be adjusted.

[0060] From the appendix Figure 3 To be continued Figure 7 It can be seen that when using the present invention to adjust the material thickness fluctuation, wedge fluctuation and convexity fluctuation, the system has a fast response and obvious adjustment effect.

Claims

1. A comprehensive control method for plate thickness, primary plate shape, and secondary plate shape based on an influence matrix. Its features include the following steps: a. The generation of the influence matrix includes the following steps: a1. Collect rolling mill parameters, including current coil and strip rolling process parameter settings and plate thickness and shape control parameter settings. The rolling mill parameters include: work roll body length L. w Support roller body length L b Working roll diameter D w Support roller diameter D b Support roller neck diameter D bn The distance between the work roll bending cylinders is L1, the center distance between the pressing cylinders is L3, and the work roll type is C. w Support roller type C b The stiffness of a single archway is N; the rolling process parameters include: incoming material width B, incoming material thickness h0, coefficient of friction μ, and deformation resistance σ. s Front tension σ1, rear tension σ0; plate thickness and shape control parameter settings include: unloaded roll gap x1, roll tilting amount x2, and roll bending force x3; a2. Based on the basic rolling theory, the exit thickness a1, primary plate shape a2, and secondary plate shape a3 can be expressed as the following functions: in: The influence matrix is ​​formed using the functions described above; b. Based on the influence matrix, comprehensively control the plate thickness, primary plate shape, and secondary plate shape; obtain the adjustment vector ΔX of the pressing amount, tilting amount, and bending force. a ; c. Adjust the vector ΔX of the reduction amount, the tilting amount, and the bending force. a When distributed to actual production equipment, deviations in plate thickness, primary plate shape, and secondary plate shape can be eliminated simultaneously.

2. The integrated control method according to claim 1, characterized in that, The formation of the influence matrix in step a2 includes the following steps: a21. Using the parameters given in a1 as input parameters, calculate the exit thickness based on the basic rolling theory. Primary plate shape With secondary plate shape a22. Let x1 = x1 + Δx1, and calculate the exit thickness at this point according to the basic rolling theory. Primary plate shape With secondary plate shape a23, Order The influence coefficient of the pressing adjustment method on the plate thickness is obtained. Influence coefficient on primary plate shape and the influence coefficient on the secondary plate shape a24. Let x2 = x2 + Δx2, x1 = x1 - Δx1, calculate the exit thickness at this point based on basic rolling theory. Primary plate shape With secondary plate shape a25, Order The influence coefficient of the tilting roller adjustment method on the plate thickness is obtained. Influence coefficient on primary plate shape and the influence coefficient on the secondary plate shape a26. Let x3 = x3 + Δx3, x2 = x2 - Δx2, calculate the exit thickness at this point based on basic rolling theory. Primary plate shape With secondary plate shape a27, Order The influence coefficient of the bending roller adjustment method on the plate thickness was obtained. Influence coefficient on primary plate shape and the influence coefficient on the secondary plate shape a28. Construct an influence matrix from the obtained influence coefficients. Solve for the inverse matrix C of the influence matrix C. -1 .

3. The integrated control method according to claim 2, characterized in that, The integrated control in step b includes the following steps: b1. Collect the current thickness deviation Δa of the coiled strip. 1a First plate shape deviation Δa 2a With secondary plate shape deviation Δa 3a ; b2. The plate thickness deviation Δa 1a 1. Primary plate shape deviation Δa 2a With secondary plate shape deviation Δa 3a Combine to form a deviation vector b3. The C obtained in step a28 -1 With deviation vector ΔA a Multiplying these values ​​and taking the negative value yields the adjustment vectors for the reduction, tilting, and bending forces.

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