An adaptive method for dead zone width of aluminum strip roll eccentricity

Abstract

This invention relates to an adaptive dead zone width method for aluminum strip rolling mill roll eccentricity, comprising the following steps: detecting the rolling force during the aluminum strip rolling process using a pressure head installed at the bottom of the rolling mill or a pressure sensor arranged in the hydraulic circuit; determining the change in roll eccentricity by analyzing the rolling force; and adaptively suppressing the influence of roll eccentricity on strip thickness variation based on a programmable controller. The dead zone width of this invention can adaptively change according to the roll eccentricity, working more seamlessly with the active roll eccentricity compensation method. When used together, they can each play their respective roles, further reducing the impact of roll eccentricity on strip thickness and achieving better overall control.

Description

Technical Field

[0001] This invention belongs to the field of aluminum sheet and strip rolling production control technology, specifically relating to an adaptive method for the dead zone width of aluminum sheet and strip roll eccentricity. Background Technology

[0002] As customers' requirements for the quality of aluminum sheet and strip increase, roll eccentricity has gradually become a major factor restricting the improvement of the thickness quality index of aluminum sheet and strip. Roll eccentricity is caused by the ellipticity of the roll itself and the misalignment error of the roll diameter, which causes periodic changes in the roll gap. This not only directly causes periodic fluctuations in the sheet and strip thickness, but also leads to malfunctions of GM-AGC (Gauge Meter Automatic Gauge Control), further reducing thickness accuracy. Therefore, to improve the sheet and strip thickness accuracy, the influence of roll eccentricity on the sheet and strip thickness must be eliminated. To this end, scholars and industry professionals at home and abroad have made great efforts and developed a variety of methods, mainly divided into active roll eccentricity compensation method and dead zone setting method. Since the active compensation method, which identifies and compensates for roll eccentricity signals, cannot completely eliminate the influence of roll eccentricity on the sheet and strip thickness, the control system still needs to set an eccentricity dead zone to prevent the uncompensated roll eccentricity from causing malfunctions of pressure AGC, thereby preventing the deterioration of thickness accuracy.

[0003] "Theory and Practice of High-Precision Strip Rolling" presents a dead-zone drift method to suppress pressure AGC malfunctions. This method keeps the dead-zone size constant but allows it to drift up and down with fluctuations in the rolling force center. "Research and Application of Dynamic Dead-Zone Method for Roll Eccentricity" presents a dynamic dead-zone method, such as... Figure 1 As shown, the dead zone width of this method can change with the thickness difference fluctuation range of GM-AGC malfunction. However, when used in conjunction with the active roll eccentricity compensation method, it leads to a deterioration in the active compensation effect, which in turn increases the thickness difference of the aluminum strip and even adversely affects the system stability after all thickness control systems are used together. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide an adaptive method for the dead zone width of aluminum strip roll eccentricity, which aims to solve the above-mentioned problems.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] An adaptive method for the dead zone width of aluminum strip roll eccentricity includes the following steps:

[0007] The rolling force during the aluminum sheet and strip rolling process is detected by a pressure head installed at the bottom of the rolling mill or by a pressure sensor arranged in the hydraulic circuit.

[0008] By analyzing the rolling force, the change in roll eccentricity is determined, and the influence of roll eccentricity on the thickness difference of the strip is adaptively suppressed based on the programmable controller.

[0009] Furthermore, the method of adaptively suppressing the influence of roll eccentricity on strip thickness difference based on programmable controllers specifically includes:

[0010] After the strip bites into the rolling mill, if the support roll rotates no more than two revolutions, an empirical constant C is used as the adaptive value DB for the dead zone width under the current number of revolutions of the i-th support roll. i DB i =C.

[0011] If the support roll rotates more than two revolutions, the controller uses the pressure head or pressure sensor to collect the maximum and minimum rolling forces of the support roll after two consecutive revolutions. By analyzing these rolling forces, the controller determines the change in roll eccentricity and adaptively calculates and sets the dead zone width accordingly.

[0012] Furthermore, the adaptive calculation and setting of the dead zone width is as follows:

[0013] The difference between the maximum and minimum rolling force of the support roll in a single turn is calculated using equation (1), and the calculated difference in rolling force ΔP for the (i-1)th turn of the support roll is compared. xn,i-1 and the difference in rolling force ΔP in the (i-2)th round xn,i-2 If △P xn,i-1 ≤△P xn,i-2 Then △P is adopted. xn,i-1 DB is the adaptive variation value of the dead zone width. i DB i =△P xn,i-1 ;

[0014] △P xn =P max -P min (1)

[0015] In the formula, P max and P min The maximum and minimum rolling forces per revolution of the support roll are collected; △P xn This represents the difference between the maximum and minimum rolling force of the support roll per revolution.

[0016] Equations (2) and (3) are used to determine the changes in the maximum and minimum rolling forces after two consecutive rotations of the support roll. When ΔP mx and △P mn When all are greater than or equal to 0, if ΔP mx ≥△P mn Then, in the previous adaptive change value DB i-1 Add 2△P to the base mxDB i =2△P mx +DB i-1 If △P mn ≥△P mx Then, in the previous adaptive change value DB i-1 Add 2△P to the base mn DB i =2△P mn +DB i-1 ;

[0017] △P mx =P max,i-1 -P max,i-2 (2)

[0018] △P mn =P min,i-2 -P min,i-1 (3)

[0019] In the formula, △P mx and △P mn These represent the maximum and minimum rolling force changes after two consecutive rotations of the support roll; P max,i-1 and P max,i-2 These represent the maximum rolling force values ​​collected by the controller for the support roll in the (i-1)th and (i-2)th revolutions, respectively; P min,i-1 and P min,i-2 These are the minimum rolling force values ​​collected by the controller for the support roller in the (i-1)th and (i-2)th cycles, respectively.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] The dead zone width of this invention can adaptively change its size according to the roll eccentricity, which works better with the active roll eccentricity compensation method. When used together, they can play their respective roles, further reducing the impact of roll eccentricity on the thickness of the strip and achieving a better overall control effect. Attached Figure Description

[0022] Figure 1 This is a control diagram of the dynamic dead zone method;

[0023] Figure 2 This is a control schematic diagram of an embodiment of the present invention;

[0024] Figure 3 This refers to the thickness deviation correction effect of the active compensation method for roll eccentricity, the active compensation and dynamic dead zone coordination, and the active compensation and dead zone width adaptive coordination.

[0025] In the figure, Δh gm and Δh cThese represent the equivalent thickness difference and the equivalent thickness difference after passing through the dynamic dead zone, respectively; ΔS' is the roll gap adjustment amount required to eliminate the thickness deviation; ΔS* is the roll gap adjustment amount given by the hydraulic roll gap control system based on the locked unloaded roll gap; ΔS ’ e Δx is the roll eccentricity compensation amount; Δx is the closed-loop position deviation of the hydraulic roll gap control; ΔS is the actual roll gap variation; Δh is the strip thickness difference; ΔP, ΔP C These are the actual rolling force change and the actual rolling force change after passing through the dynamic dead zone, respectively; S FBK This is the roll gap feedback value; S 0f For unloaded roll gaps; P act P lock P REF These represent the actual rolling force, the locked rolling force, and the given rolling force, respectively; ΔH is the entry thickness difference; ΔP S is the change in rolling force corresponding to the thickness difference at the inlet; M and Q are the mill stiffness coefficient and the workpiece plasticity coefficient, respectively. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0027] Please refer to Figure 1 This invention provides an adaptive method for the dead zone width of aluminum strip roll eccentricity, comprising the following steps:

[0028] The rolling force during the aluminum sheet and strip rolling process is detected by a pressure head installed at the bottom of the rolling mill or by a pressure sensor arranged in the hydraulic circuit.

[0029] By analyzing the rolling force, the change in roll eccentricity is determined, and the influence of roll eccentricity on the thickness difference of the strip is adaptively suppressed based on the programmable controller.

[0030] In this embodiment, the influence of roll eccentricity on the thickness difference of the strip is adaptively suppressed based on the programmable controller, specifically as follows:

[0031] After the strip bites into the rolling mill, if the support roll rotates no more than two revolutions, an empirical constant C is used as the adaptive value DB for the dead zone width under the current number of revolutions of the i-th support roll. i DB i =C.

[0032] If the support roll rotates more than two revolutions, the controller uses the pressure head or pressure sensor to collect the maximum and minimum rolling forces of the support roll after two consecutive revolutions. By analyzing these rolling forces, the controller determines the change in roll eccentricity and adaptively calculates and sets the dead zone width accordingly.

[0033] In this embodiment, the dead zone width is adaptively calculated and set as follows:

[0034] The difference between the maximum and minimum rolling force of the support roll in a single turn is calculated using equation (1), and the calculated difference in rolling force ΔP for the (i-1)th turn of the support roll is compared. xn,i-1 and the difference in rolling force ΔP in the (i-2)th round xn,i-2 If △P xn,i-1 ≤△P xn,i-2 Then △P is adopted. xn,i-1 DB is the adaptive variation value of the dead zone width. i DB i =△P xn,i-1 ;

[0035] △P xn =P max -P min (1)

[0036] In the formula, P max and P min The maximum and minimum rolling forces per revolution of the support roll are collected; △P xn This represents the difference between the maximum and minimum rolling force of the support roll per revolution.

[0037] Equations (2) and (3) are used to determine the changes in the maximum and minimum rolling forces after two consecutive rotations of the support roll. When ΔP mx and △P mn When all are greater than or equal to 0, if ΔP mx ≥△P mn Then, in the previous adaptive change value DB i-1 Add 2△P to the base mx DB i =2△P mx +DB i-1 If △P mn ≥△P mx Then, in the previous adaptive change value DB i-1 Add 2△P to the base mn DB i =2△P mn +DB i-1 ;

[0038] △P mx =P max,i-1 -P max,i-2 (2)

[0039] △P mn =P min,i-2 -P min,i-1 (3)

[0040] In the formula, △P mx and △P mnThese represent the maximum and minimum rolling force changes after two consecutive rotations of the support roll; P max,i-1 and P max,i-2 These represent the maximum rolling force values ​​collected by the controller for the support roll in the (i-1)th and (i-2)th revolutions, respectively; P min,i-1 and P min,i-2 These are the minimum rolling force values ​​collected by the controller for the support roller in the (i-1)th and (i-2)th cycles, respectively.

[0041] To verify the effectiveness of this invention, the roll eccentricity formed by equation (4) was compensated based on the original active roll eccentricity compensation method of the system. The combined effect of the dynamic dead zone method and the active roll eccentricity compensation method, as well as the combined effect of the dead zone width adaptive method proposed in this invention and the active roll eccentricity compensation method, were compared. During system operation, the active roll eccentricity compensation was put into operation at 3s. Based on this, the dynamic dead zone method and the dead zone width adaptive method were added at 6s to correct the combined effect of the active roll eccentricity compensation. The sheet thickness deviation correction effects of the three cases are as follows: Figure 3 As shown.

[0042] like Figure 3 After active roll eccentricity compensation at the 3rd second, the impact of roll eccentricity on strip thickness is significantly reduced, improving the strip thickness control accuracy. After adding a dynamic dead zone at the 6th second, the actual strip thickness difference amplitude is greater than without the dynamic dead zone, resulting in poorer thickness accuracy. After adding adaptive dead zone width at the 6th second, the amplitude of the actual rolled strip thickness difference is further reduced. Therefore, it can be seen that the proposed method of adaptive dead zone width combined with active roll eccentricity compensation can better eliminate the impact of roll eccentricity on strip thickness.

[0043] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A method for adaptive dead zone width in aluminum strip roll eccentricity, characterized in that, Includes the following steps: The rolling force during the aluminum strip rolling process is detected by a pressure head installed at the bottom of the rolling mill or by a pressure sensor arranged in the hydraulic circuit. By analyzing the rolling force, the change in roll eccentricity is determined, and the influence of roll eccentricity on the thickness difference of the strip is adaptively suppressed based on the programmable controller. The method for adaptively suppressing the influence of roll eccentricity on strip thickness difference based on programmable controller is as follows: After the strip bites into the rolling mill, if the support roll rotates no more than two revolutions, an empirical constant C is used as the adaptive value DB for the dead zone width under the current number of revolutions of the i-th support roll. i DB i =C; If the support roll rotates more than two revolutions, the controller uses the pressure head or pressure sensor to collect the maximum and minimum rolling forces of the support roll after two consecutive revolutions. By analyzing these rolling forces, the controller determines the change in roll eccentricity and adaptively calculates and sets the dead zone width accordingly. The adaptive calculation and setting of the dead zone width are as follows: The difference between the maximum and minimum rolling force of the support roll in a single turn is calculated using equation (1), and the calculated difference in rolling force ΔP for the (i-1)th turn of the support roll is compared. xn,i-1 and the difference in rolling force ΔP in the (i-2)th round xn,i-2 If △P xn,i-1 ≤△P xn,i-2 Then △P is adopted. xn,i-1 DB is the adaptive variation value of the dead zone width. i DB i =△P xn,i-1 ; △P xn =P max -P min (1) In the formula, P max and P min The maximum and minimum rolling forces per revolution of the support roll are collected; △P xn This represents the difference between the maximum and minimum rolling force of the support roll per revolution. Equations (2) and (3) are used to determine the changes in the maximum and minimum rolling forces after two consecutive rotations of the support roll. When ΔP mx and △P mn When all are greater than or equal to 0, if ΔP mx ≥△P mn Then, in the previous adaptive change value DB i-1 Add 2△P to the base mx DB i =2△P mx + DB i-1 If △P mn ≥△P mx Then, in the previous adaptive change value DB i-1 Add 2△P to the base mn DB i =2△P mn + DB i-1 ; △P mx =P max,i-1 -P max,i-2 (2) △P mn =P min,i-2 -P min,i-1 (3) In the formula, △P mx and △P mn These represent the maximum and minimum rolling force changes after two consecutive rotations of the support roll; P max,i-1 and P max,i-2 These represent the maximum rolling force values ​​collected by the controller for the support roll in the (i-1)th and (i-2)th revolutions, respectively; P min,i-1 and P min,i-2 These are the minimum rolling force values ​​collected by the controller for the support roller in the (i-1)th and (i-2)th cycles, respectively.

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