A Feedforward Thickness Control Method for Hot Strip Mill Based on Kinetic Analysis

Abstract

The present invention provides a feedforward thickness control method for a hot tandem rolling mill based on dynamic analysis, which relates to the technical field of rolling mill control and includes: establishing a dynamic model of the rolling mill of the hot tandem rolling mill unit and listing the dynamic equation in the vertical direction of the rolling mill; inputting the rolling force parameters in the rolling process into the dynamic equation in the vertical direction of the rolling mill, and obtaining the vibration displacement data of the work roll of the rolling mill through calculation; calculating the roll gap adjustment amount of the next stand according to the thickness fluctuation data at the outlet of the strip of the previous stand, and implementing the roll gap adjustment by the screwdown control system according to the calculated roll gap adjustment amount; the present invention greatly eliminates the influence of the thickness fluctuation of the strip between stands caused by the vibration of the rolling mill on the thickness accuracy of the finished strip through the thickness feedforward control method based on dynamic analysis, and solves the problem that it is difficult for the traditional feedforward AGC control method to know the thickness fluctuation of the strip between stands. By adopting the thickness feedforward control method for the hot tandem rolling mill based on dynamic analysis of the present invention, the accuracy of strip thickness control is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of rolling mill control, and in particular, to a feedforward thickness control method for a hot tandem rolling mill based on dynamic analysis. Background Art

[0002] The thickness accuracy of strip steel is one of the most important quality indicators of hot-rolled strip steel. With the rise and development of civil and military industries such as aerospace, precision instruments, civil construction, and automobile production, strict requirements are imposed on the thickness accuracy of hot-rolled strip steel.

[0003] The automatic thickness control system of a hot tandem rolling mill generally includes three thickness control methods: feedforward AGC, thickness gauge AGC, and monitoring AGC. Among them, the conventional feedforward AGC control method is the plastic coefficient feedforward AGC, which measures the hardness distribution of the strip at the entrance stand and adjusts the roll gap of the downstream stand to correct the thickness deviation caused by the change in the hardness of the incoming material and improve the accuracy of the overall thickness control.

[0004] However, the feedforward AGC in the existing automatic thickness control system has an inherent defect. Since its control effect depends on the calculation accuracy of the strip plastic coefficient, it cannot accurately reflect the thickness fluctuation of the strip between stands for the downstream stand to adjust the roll gap. As the strip specifications rolled by the rolling mill become thinner and thinner, the vibration generated by the rolling mill becomes more and more serious. Therefore, the thickness fluctuation of the strip under the vibration of the rolling mill becomes larger and larger, resulting in the thickness of the strip at the entrance of each stand not accurately hitting the thickness preset by the rolling process, and ultimately resulting in the thickness accuracy of the finished strip not meeting the requirements. The prior art improves the feedforward thickness control accuracy by adding a mechanical property detector at the entrance of the rolling mill. First, this increases the investment cost of the unit. Second, it is impossible to realize the real-time detection of the thickness fluctuation of the strip between stands. At present, there is only a thickness gauge at the exit of the 7th stand F7 of the hot tandem rolling mill. If thickness gauges are added between other stands to detect the thickness of the strip, this will result in huge equipment investment costs and increase the equipment maintenance costs. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to propose a feedforward thickness control method for a hot tandem rolling mill based on dynamic analysis to solve the problem that the prior art cannot accurately reflect the thickness fluctuation of the strip between stands.

[0006] The technical means adopted by the present invention are as follows:

[0007] A feedforward thickness control method for a hot tandem rolling mill based on dynamic analysis, the control method comprising the following steps:

[0008] Establish a rolling mill dynamics model for the hot tandem rolling mill according to the equipment size and the layout form of the hot tandem rolling mill, and list the dynamic equation in the vertical direction of the rolling mill according to the vibration theory;

[0009] Input the rolling force parameters in the rolling process into the dynamic equation of the mill in the vertical direction and calculate to obtain the vibration displacement data of the work rolls of the mill;

[0010] Obtain the thickness fluctuation data of the strip at the mill outlet according to the relationship between the vibration displacement data of the work rolls and the strip thickness at the mill outlet;

[0011] Calculate the roll gap adjustment amount for the next stand according to the strip thickness fluctuation data at the outlet of the previous stand, and the roll gap adjustment is implemented by the screwdown control system according to the calculated roll gap adjustment amount to achieve thickness control.

[0012] Furthermore, the steps for establishing the dynamic model of the hot strip mill and listing the dynamic equation of the mill in the vertical direction are as follows:

[0013] Calculate the equivalent mass and equivalent stiffness of the mill system through the principle of energy conservation,

[0014] The calculation formula for the equivalent mass is:

[0015] M i＝ 2T max / (ωY imax ) 2

[0016] The calculation formula for the equivalent stiffness is:

[0017] K i =2V imax / (Y imax ) 2

[0018] Where: M i represents the equivalent mass of the mill components, K i represents the equivalent stiffness between the mill components, T imax represents the maximum kinetic energy of the mill components when vibration occurs, V imax represents the maximum vibration speed of the mill components during the vibration process, Y imax represents the maximum vibration displacement of the mill components when vibration occurs;

[0019] According to the vibration theory, list the dynamic equation of the mill in the vertical direction, and the dynamic equation includes:

[0020]

[0021] Where, M represents the mass matrix of the mill dynamic system, K represents the stiffness matrix of the mill dynamic system, F act represents the actual rolling force during the rolling process of the mill, represents the acceleration column vector of the mill dynamic system, {z} represents the displacement column vector of the mill dynamic system;

[0022] The calculation formula for the mass matrix M of the rolling mill dynamic system is as follows:

[0023]

[0024] Among them, M1 represents the equivalent mass of the columns, upper crossbeam, pads, and hydraulic cylinders on the rolling mill stand; M2 represents the equivalent mass of the upper backup rolls, bearings, and chocks of the rolling mill; M3 represents the equivalent mass of the work rolls on the rolling mill; M4 represents the equivalent mass of the lower work rolls of the rolling mill; M5 represents the equivalent mass of the lower backup rolls, bearings, and chocks of the rolling mill; M6 represents the equivalent mass of the lower columns, lower crossbeam, pads, and pressure gauges of the rolling mill stand;

[0025] The calculation formula for the stiffness matrix K of the rolling mill dynamic system in the vertical direction is as follows:

[0026]

[0027] Among them, K1 represents the equivalent stiffness of the columns and upper crossbeam of the rolling mill stand; K2 represents the equivalent stiffness from the middle of the upper backup rolls to the middle of the upper crossbeam of the rolling mill; K3 represents the equivalent stiffness between the upper backup rolls and the upper work rolls; K4 represents the equivalent stiffness between the work rolls and the rolled piece; K5 represents the equivalent stiffness between the lower backup rolls and the lower work rolls; K6 represents the equivalent stiffness from the middle of the lower backup rolls to the middle of the lower crossbeam of the rolling mill; K7 represents the equivalent stiffness of the lower crossbeam, lower columns, side pressure, and pads.

[0028] Furthermore, the step of inputting the rolling force parameters in the rolling process into the dynamic equation of the rolling mill in the vertical direction and calculating to obtain the vibration displacement data of the work rolls of the rolling mill includes the following steps:

[0029] Export the actual rolling force in the rolling process and input it into the dynamic equation;

[0030] Perform real-time solution of the dynamic equation by the Runge-Kutta method to obtain the vibration displacement of the work rolls of the rolling mill.

[0031] Furthermore, the step of obtaining the thickness fluctuation data of the strip at the exit of the rolling mill according to the relationship between the vibration displacement data of the work rolls and the thickness of the strip at the exit of the rolling mill includes the following steps:

[0032] Obtain the thickness value of the strip at the exit of the rolling mill under the vibration of the work rolls of the rolling mill according to the rolling mill spring equation. The calculation formula for the thickness value of the strip at the exit of the rolling mill is as follows:

[0033] h = S P + x

[0034] Among them: h represents the thickness value of the strip under the vibration of the work rolls of the rolling mill, S P represents the loaded roll gap of the rolling mill, and x represents the vibration displacement of the work rolls of the rolling mill;

[0035] The calculation formula for the loaded roll gap of the rolling mill is as follows:

[0036]

[0037] Among them, S′ represents the no-load roll gap of the rolling mill, P represents the preset rolling force of the rolling mill, and C′ represents the total stiffness of the rolling mill housing;

[0038] By the preset value of the strip thickness during the rolling process of the rolling mill and the strip thickness value under the vibration of the work rolls of the rolling mill, the strip thickness fluctuation amount Δh under the vibration condition of the work rolls of the rolling mill is obtained, and its calculation formula is:

[0039] Δh = h0 - h;

[0040] Among them, h0 is the preset value of the strip thickness during the rolling process of the rolling mill, and h is the strip thickness value under the vibration of the work rolls of the rolling mill.

[0041] Further, calculating the roll gap adjustment amount of the next stand according to the strip outlet thickness fluctuation data of the previous stand, and the roll gap adjustment is implemented by the screwdown control system according to the calculated roll gap adjustment amount, which includes the following steps:

[0042] According to the strip thickness fluctuation amount at the outlet of the rolling mill under the vibration of the work rolls of the rolling mill, calculate the roll gap adjustment amount, and the calculation formula for the roll gap adjustment amount is:

[0043] ΔS = Δh × Q / C′

[0044] Among them, ΔS represents the roll gap adjustment amount, Δh represents the strip thickness fluctuation value, Q represents the strip plasticity coefficient, and C′ represents the total stiffness of the rolling mill housing;

[0045] Obtain the real-time movement speed of the strip between stands, integrate according to the sampling period of the process data of the rolling mill process system to obtain the real-time position of the strip head, and predict the time when the strip head enters the roll gap;

[0046] Obtain the relationship between the rolling force of the rolling mill and the speed of the rolling mill hydraulic cylinder performing the screwdown action through the nip test, and predict the response time required for the roll gap change under the current rolling force;

[0047] Use the difference between the time when the strip head enters the roll gap and the response time required for the rolling mill hydraulic cylinder to screw down to obtain the delay time, and the calculation formula for the delay time is:

[0048] Δt = t a - t b

[0049] Among them, t a is the time when the strip head enters the roll gap, t bis the required response time for the roll gap change under the current rolling force;

[0050] After a time delay of Δt, the roll gap of the screwdown control system is adjusted in real time.

[0051] Compared with the prior art, the present invention has the following advantages:

[0052] The present invention uses dynamic analysis means to calculate the thickness fluctuation value of the strip at the outlet of the previous stand under the condition of mill vibration, and uses this value for the calculation of the feedforward AGC of the next stand. Through the feedforward thickness control method of the hot strip mill based on dynamic analysis provided by the present invention, the numerical value of the strip thickness fluctuation between stands can be obtained and utilized in the feedforward AGC control process. The present invention can greatly eliminate the influence of the strip thickness fluctuation on the thickness deviation of the finished strip under the condition of mill vibration, ensure the finished product quality of the strip, and does not require additional equipment investment, which has a positive significance for improving the finished thickness accuracy in the length direction of the whole coil of strip steel and ensuring the rolling stability. Description of the Drawings

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0054] Figure 1 is the flow chart of the control method of the present invention.

[0055] Figure 2 is the schematic diagram of the dynamic model of the present invention.

[0056] Figure 3 is the schematic diagram of the calculation curve of the vibration displacement of the work roll of the mill of the present invention.

[0057] Figure 4 is the fluctuation curve diagram of the strip thickness under the condition of mill vibration of the present invention. Detailed Embodiments

[0058] In order to enable those skilled in the art to better understand the solution of the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0059] It should be noted that the terms "first", "second", etc. in the description, claims and above-mentioned drawings of the present invention are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0060] As Figure 1 shown, the present invention provides a feedforward thickness control method for a hot continuous rolling mill based on dynamic analysis, comprising the following steps:

[0061] Step 1: Establish a dynamic model of the hot continuous rolling mill in the vertical direction and list the dynamic equations.

[0062] Specifically, Step 1 is as follows:

[0063] Step 1.1, from the design dimension data of the rolling mill, calculate the equivalent mass and equivalent stiffness of each component of the rolling mill system through the principle of energy conservation, and the calculation formulas are as follows:

[0064] Equivalent mass: M i＝ 2T max / (ωY imax ) 2 ;

[0065] Equivalent stiffness: K i =2V imax / (Y imax ) 2 ;

[0066] In the formula, M i represents the equivalent mass of the rolling mill component, K i represents the equivalent stiffness between the rolling mill components, T imax represents the maximum kinetic energy of the rolling mill component during vibration, V imax represents the maximum vibration velocity of the rolling mill component during the vibration process, and Y imax represents the maximum vibration displacement of the rolling mill component during vibration.

[0067] (1) Calculation of equivalent stiffness

[0068] 1) Calculation of K1

[0069]

[0070] In the formula: KLZ is the stiffness of the column, K L is the stiffness of the upper crossbeam, K HS is the stiffness of the oil cylinder piston, K DK is the stiffness of the cushion block.

[0071] 2) Calculation of K2

[0072]

[0073] In the formula: K ZW is the bending deformation stiffness of the upper backup roll, K Zy is the oil film stiffness of the upper backup roll, K y is the stiffness of the hydraulic oil, K gt is the stiffness of the rigid body of the hydraulic cylinder, K Z is the stiffness of the upper backup roll bearing housing

[0074] 3) Calculation of K3 and K5

[0075]

[0076] Among them,

[0077] 4) Calculation of K4

[0078]

[0079] In the formula: M p is the plastic deformation stiffness of the rolled piece, K * is the elastic flattening amount of the roll.

[0080] 5) Calculation of K6

[0081]

[0082] In the formula: K zw is the bending deformation stiffness of the lower backup roll, K zy is the oil film stiffness of the lower backup roll bearing, K z is the stiffness of the lower backup roll bearing housing.

[0083] 6) Calculation of K7

[0084] K7 = K L1

[0085] In the formula: K L1 is the stiffness of the lower crossbeam

[0086] (2) Calculation of the equivalent mass

[0087] 1) Calculation of M1

[0088] M1 = (K1 / K t )2 ×(M p +M t ) + 2M d + 2M s

[0089] Where K t is the equivalent stiffness of the upper part of the column and the upper crossbeam, M t is the equivalent mass of the upper crossbeam, M d is the mass of the spacer block, M s is the mass of the oil cylinder piston.

[0090] 2) Calculation of M2 and M5

[0091] M2 = M zg + 2M gt + 2M zz + M ph

[0092] Where: M zg is the mass of the backup roll and the inner sleeve of the backup roll bearing, M gt is the mass of the cylinder block, M zz is the mass of the backup roll bearing housing, M ph is the mass of the balance device.

[0093] 3) Calculation of M3 and M4

[0094]

[0095] Where M b1 is the mass of the work roll body, M c1 is the mass of the work roll bearing and bearing housing, M n1 is the mass of the work roll diameter.

[0096] 4) Calculation of M6

[0097] M6 = M b + M x

[0098] Where M b is the equivalent mass of the lower crossbeam, M x is the mass of the wedge.

[0099] Based on this, the equivalent mass and equivalent stiffness of each component of the rolling mill system are obtained, as Figure 2 shown, and a dynamic model of the rolling mill system is established.

[0100] Step 1.2, according to the vibration theory, list the dynamic equation of the six-degree-of-freedom undamped system in the vertical direction of the rolling mill:

[0101]

[0102] In the formula, M represents the mass matrix of the rolling mill dynamic system, K represents the stiffness matrix of the rolling mill dynamic system, and F act represents the rolling force during the rolling process of the rolling mill, represents the acceleration column vector of the rolling mill dynamic system, and {z} represents the displacement column vector of the rolling mill dynamic system.

[0103] Among them, the calculation formula for the mass matrix M of the rolling mill dynamic system is:

[0104]

[0105] In the formula, M1 represents the equivalent mass of the columns, upper crossbeam, pads, and hydraulic cylinders on the rolling mill stand, M2 represents the equivalent mass of the upper backup rolls, bearings, and bearing seats of the rolling mill, M3 represents the equivalent mass of the upper work rolls of the rolling mill, M4 represents the equivalent mass of the lower work rolls of the rolling mill, M5 represents the equivalent mass of the lower backup rolls, bearings, and bearing seats of the rolling mill, and M6 represents the equivalent mass of the lower columns, lower crossbeam, pads, and pressure gauges on the rolling mill stand.

[0106] The calculation formula for the stiffness matrix K of the rolling mill dynamic system is:

[0107]

[0108] In the formula, K1 represents the equivalent stiffness of the columns and upper crossbeam on the rolling mill stand, K2 represents the equivalent stiffness from the middle of the upper backup rolls to the middle of the upper crossbeam, K3 represents the equivalent stiffness between the upper backup rolls and the upper work rolls, K4 represents the equivalent stiffness between the work rolls and the rolled piece, K5 represents the equivalent stiffness between the lower backup rolls and the lower work rolls, K6 represents the equivalent stiffness from the middle of the lower backup rolls to the middle of the lower crossbeam, and K7 represents the equivalent stiffness of the lower crossbeam, lower columns, side pressure, and pads.

[0109] Step 2: Substitute the actual rolling force F act during the rolling process into the dynamic equation, solve the dynamic equation, and obtain the vibration displacement data of the work rolls of the rolling mill during the rolling process.

[0110] Step 2 specifically includes:

[0111] Step 2.1, export the rolling force parameters in the rolling process system and sample them at a sampling rate of 50 - 500 Hz. In this embodiment, the change range of the rolling force is: 150 - 200 tons;

[0112] Step 2.2, substitute the sampled rolling force value into the dynamic equation and perform real-time calculation through the Runge - Kutta method to obtain the vibration displacement data of the work rolls of the rolling mill, as Figure 3 shown.

[0113] Step 3: Obtain the strip thickness fluctuation data at the mill outlet based on the relationship between the work roll vibration displacement data and the strip thickness at the mill outlet.

[0114] Step 3 specifically includes:

[0115] Step 3.1, obtain the strip thickness value under the condition of work roll vibration of the mill according to the mill spring equation, and its calculation formula is:

[0116] h = S P + x

[0117] In the formula, h represents the strip thickness value under the condition of work roll vibration of the mill, S P represents the loaded roll gap of the mill, and x represents the vibration displacement of the work roll of the mill.

[0118] Among them, the calculation formula for the loaded roll gap S P of the mill is:

[0119]

[0120] In the formula, S′ represents the no-load roll gap of the mill, P represents the preset rolling force of the mill, and C′ represents the total stiffness of the mill housing.

[0121] Step 3.2, obtain the strip thickness fluctuation amount Δh under the condition of work roll vibration of the mill by comparing the preset strip thickness value h0 during the rolling process of the mill with the strip thickness value h obtained in Step 3.1, and its calculation formula is:

[0122] Δh = h0 - h

[0123] The fluctuation curve of the strip thickness under the condition of mill vibration is as Figure 4 shown.

[0124] Step 4: Calculate the roll gap adjustment amount ΔS for the next stand based on the strip thickness fluctuation data at the outlet of the previous stand, and the roll gap adjustment is implemented by the screwdown control system according to the calculated roll gap adjustment amount.

[0125] Step 4 specifically includes:

[0126] Step 4.1, calculate the roll gap adjustment amount ΔS according to the strip thickness fluctuation amount Δh obtained in Step 3.2, and its calculation formula is:

[0127] ΔS = Δh × Q / C′

[0128] In the formula, ΔS represents the roll gap adjustment amount, Δh represents the strip thickness fluctuation value, Q represents the strip plasticity coefficient, and C′ represents the total stiffness of the mill housing;

[0129] Step 4.2: Obtain the real-time moving speed of the strip between stands, get the real-time position of the strip head according to the sampling period of the process data of the rolling mill process system, and predict the time t when the strip head enters the roll gap. a ;

[0130] Step 4.3: Obtain the relationship between the rolling force of the rolling mill and the speed of the rolling mill hydraulic cylinder performing the pressing-down action through a pressing test, and predict the response time t required for the roll gap change under the current rolling force. b ;

[0131] Step 4.4: Use the time difference Δt between the time when the strip head enters the roll gap in Step 4.2 and the response time required for the rolling mill hydraulic cylinder to press down in Step 4.3 as the delay time, and its calculation formula is:

[0132] Δt = t a -t b

[0133] After delaying by Δt, the real-time roll gap of the press-down control system is adjusted.

[0134] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A feedforward thickness control method for a hot strip mill based on kinetic analysis, characterized in that The control method includes the following steps: Establish a rolling mill dynamics model of the hot strip mill according to the equipment size and the layout form of the hot strip mill, and list the dynamics equation in the vertical direction of the rolling mill according to the vibration theory; Input the rolling force parameters in the rolling process into the dynamics equation in the vertical direction of the rolling mill and calculate to obtain the vibration displacement data of the work roll of the rolling mill; Obtain the thickness fluctuation data of the strip at the outlet of the rolling mill according to the relationship between the vibration displacement data of the work roll and the thickness of the strip at the outlet of the rolling mill; Calculate the roll gap adjustment amount of the next stand according to the thickness fluctuation data of the strip at the outlet of the previous stand, and the roll gap is adjusted by the screw down control system according to the calculated roll gap adjustment amount to achieve thickness control; The steps of establishing the rolling mill dynamics model of the hot strip mill and listing the dynamics equation in the vertical direction of the rolling mill include the following steps: Calculate the equivalent mass and equivalent stiffness of the rolling mill system through the principle of energy conservation, The calculation formula of the equivalent mass is: The calculation formula of the equivalent stiffness is: Wherein: represents the equivalent mass of the rolling mill components, represents the equivalent stiffness between the rolling mill components, represents the maximum kinetic energy of the rolling mill components when vibration occurs, represents the maximum vibration velocity of the rolling mill components during the vibration process, represents the maximum vibration displacement of the rolling mill components during vibration; According to the vibration theory, list the dynamics equation in the vertical direction of the rolling mill, and the dynamics equation includes: Among them, represents the mass matrix of the rolling mill dynamic system, represents the stiffness matrix of the rolling mill dynamic system, represents the actual rolling force during the rolling process of the rolling mill, represents the acceleration column vector of the rolling mill dynamic system, represents the displacement column vector of the rolling mill dynamic system; Mass matrix of the rolling mill dynamics system The calculation formula is as follows: Among them, represents the equivalent mass of the upright columns, upper crossbeam, pads, and hydraulic cylinders on the rolling mill stand, represents the equivalent mass of the upper backup rolls, bearings, and chocks on the rolling mill, represents the equivalent mass of the work rolls on the rolling mill, represents the equivalent mass of the lower work rolls on the rolling mill, represents the equivalent mass of the lower backup rolls, bearings, and chocks on the rolling mill, represents the equivalent mass of the lower upright columns, lower crossbeam, pads, and pressure gauges on the rolling mill stand; Stiffness matrix of the rolling mill vertical direction dynamic system The calculation formula is as follows: Among them, represents the equivalent stiffness of the upper crossbeam of the rolling mill housing, represents the equivalent stiffness from the middle of the upper backup roll to the middle of the upper crossbeam of the rolling mill, represents the equivalent stiffness between the upper backup roll and the upper work roll, represents the equivalent stiffness between the work roll and the rolled piece, represents the equivalent stiffness between the lower backup roll and the lower work roll, represents the equivalent stiffness from the middle of the lower backup roll to the middle of the lower crossbeam, represents the equivalent stiffness of the lower crossbeam, lower columns, side pressure and pads.

2. The feedforward thickness control method for a hot tandem rolling mill based on kinetic analysis according to claim 1, characterized in that, The steps of inputting the rolling force parameters in the rolling process into the dynamics equation in the vertical direction of the rolling mill and calculating to obtain the vibration displacement data of the work roll of the rolling mill include the following steps: Derive the actual rolling force in the rolling process and input it into the dynamics equation; Perform real-time solution of the dynamics equation by the Runge-Kutta method to obtain the vibration displacement of the work roll of the rolling mill.

3. The feedforward thickness control method for a hot tandem rolling mill based on kinetic analysis according to claim 1, characterized in that, The steps of obtaining the thickness fluctuation data of the strip at the outlet of the rolling mill according to the relationship between the vibration displacement data of the work roll and the thickness of the strip at the outlet of the rolling mill include the following steps: Obtain the thickness value of the strip at the outlet of the rolling mill under the vibration of the work roll of the rolling mill according to the rolling mill springback equation, and the calculation formula of the thickness value of the strip at the outlet of the rolling mill is: Wherein: represents the strip thickness value under the vibration condition of the work roll of the rolling mill, represents the loaded roll gap of the rolling mill, represents the vibration displacement of the work roll of the rolling mill; The calculation formula of the loaded roll gap of the rolling mill is: Among them, represents the no-load roll gap of the rolling mill, represents the preset rolling force of the rolling mill, represents the total stiffness of the rolling mill housing; Obtain the strip thickness fluctuation amount under the vibration condition of the work roll of the rolling mill by using the preset strip thickness value during the rolling process of the rolling mill and the strip thickness value under the vibration condition of the work roll of the rolling mill , and its calculation formula is: ； Among them, is the preset value of the strip thickness during the rolling process of the rolling mill, is the strip thickness value under the condition of the vibration of the work roll of the rolling mill.

4. The feed-forward thickness control method of the hot tandem rolling mill based on kinetic analysis according to claim 1, characterized in that The steps of calculating the roll gap adjustment amount of the next stand according to the thickness fluctuation data of the strip at the outlet of the previous stand and adjusting the roll gap by the screw down control system according to the calculated roll gap adjustment amount include the following steps: Calculate the roll gap adjustment amount according to the thickness fluctuation amount of the strip at the outlet of the rolling mill under the vibration of the work roll of the rolling mill, and the calculation formula of the roll gap adjustment amount is: Among them, represents the roll gap adjustment amount, represents the strip thickness fluctuation value, represents the strip plastic coefficient, represents the total stiffness of the rolling mill stand; Obtain the real-time movement speed of the strip between stands, integrate according to the sampling period of the process data of the rolling mill process system to obtain the real-time position of the strip head, and predict the time when the strip head enters the roll gap; Obtain the relationship between the rolling force of the rolling mill and the speed of the rolling mill hydraulic cylinder performing the screw down action through the nip test, and predict the response time required for the roll gap change under the current rolling force; Obtain the delay time by using the difference between the time when the strip head enters the roll gap and the response time required for the screw down of the rolling mill hydraulic cylinder, and the calculation formula of the delay time is: Among them, is the time when the head of the strip enters the roll gap, is the response time required for the roll gap to change under the current rolling force; Delay Press down the real-time roll gap adjustment of the control system later.

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