JPH07115057B2 - Plate shape control method in rolling mill - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for controlling a plate shape in a rolling mill, and more particularly to a method for controlling a plate shape of a rolled plate material obtained by rolling with high accuracy.

[0002]

BACKGROUND ART Conventionally, when rolling a metal plate material such as aluminum using a rolling machine such as a four-high rolling mill or a six-high rolling mill, an edge wave phenomenon in which both end portions in the width direction of the obtained rolled metal sheet are wavy or , As the middle part of the phenomenon of wavy elongation, its shape defect has been recognized, and for this reason, the rolling leveling adjusting device, work roll bending force adjusting device, work roll bending differential force adjusting device provided in the rolling mill, The plate shape is corrected by operating each actuator such as the intermediate roll bending force adjusting device.

For example, in Japanese Patent Publication No. 1-50485, a shape detector capable of detecting shapes at a plurality of positions in the width direction of a rolled plate and a plurality of shape correction mechanisms (eg, horizontal roll bending mechanism, vertical roll bender, In a shape control system for thin sheet rolling having a rolling mill left / right leveling) and an arithmetic processing unit, the output distribution of the shape detector and the target shape distribution are expressed as a function of the position in the strip width direction, and the unit operation amount of each shape correction mechanism is also expressed. The output distribution of the shape detector with respect to is expressed by a function in the plate width direction, an evaluation function for evaluating the shape over the entire plate width is calculated from these functions, and the shape correction mechanism of each shape correction mechanism that minimizes this evaluation function is calculated. A method has been disclosed in which the operation amount is calculated by an arithmetic processing unit and the shape is controlled by this operation amount.

However, in such a shape control method for rolling a thin plate, there is no response to the detection delay of the plate shape by the shape detector, and a horizontal roll bending mechanism, a vertical roll bender, and a rolling machine as a shape correcting mechanism. Since there is no response to actuator response delays such as left and right leveling, there is a delay in control for shape changes, which makes it difficult to obtain highly accurate plate shapes. Because it does not measure and utilize the change in differential load, it is difficult to control high response to changes in rolling load during acceleration / deceleration during rolling, which is a problem especially in the rolling of aluminum sheet materials, and shape changes due to changes in rolling differential load. There is also an inherent problem.

[0005]

The present invention has been made in view of such circumstances, and its object is to cope with a detection delay and a response delay of an actuator, a change in rolling load, and a rolling difference. It is an object of the present invention to provide a method capable of achieving highly stable and highly responsive control of a plate shape that copes with a load change, and thereby achieving higher performance control of the plate shape.

[0006]

In order to solve such a problem, the present invention is directed to a reduction leveling adjusting device, a work roll bending force adjusting device and a work roll bending differential force adjusting device, or an intermediate roll bending force adjusting device together with those adjusting devices. In the method of controlling the plate shape in the rolling mill equipped with, while detecting the change in the rolling load and the change in the rolling differential load, the tension distribution in the plate width direction of the rolled plate material immediately after rolling is detected, and first, the tension distribution value. After calculating the plate strain distribution in the plate width direction based on, calculate a shape parameter expressing the plate shape defect from the plate strain distribution, then, this shape parameter and the detected rolling load change value and rolling differential load The value of the disturbance to be corrected in each adjusting device is estimated while compensating the detection delay of the shape parameter from the change value. There, and based on this estimate,
A plate shape control in a rolling mill, characterized in that, while compensating a response delay of each of the adjusting devices, each of the adjusting devices is operated to control the plate shape of the rolled plate material in the rolling mill. The method is the gist of the method.

[0007]

SPECIFIC CONFIGURATION / OPERATION By the way, the outline of the plate shape control method according to the present invention as described above is shown as a model as shown in FIG.
On the outlet side of the rolling mill 4, the tension distribution detecting sensor roll 6 such as a split roll provided with a load cell is used to measure the tension at a plurality of positions in the strip width direction, and the tension distribution in the strip width direction: σ (x) [x: position in the width direction] is detected, and the plate shape of the rolled material 2 is grasped.

In FIG. 1, as the rolling mill 4, the work rolls 4 located above and below the material to be rolled 2 are used.
a, 4a, intermediate rolls 4b, 4b, and backup rolls 4c, 4c are shown as an example of a 6-high rolling mill, but as is well known, in the case of a 4-high rolling mill, Then, the upper and lower intermediate rolls 4b and 4b are not provided. In addition, such a rolling mill 4 includes
Although not shown, as well known, a reduction leveling adjusting device, a work roll bending force adjusting device,
Actuators such as a work roll bending differential force adjusting device and an intermediate roll bending force adjusting device are provided, and the plate shape of the rolled material 2 to be rolled can be variously changed by operating these actuators. Is there. Furthermore, the rolling mill 4 includes
The load cells 8 and 9 are provided so that the change in rolling load: ΔP and the change in rolling differential load: Δq can be detected.

Then, based on the tension distribution value in the plate width direction: σ (x) detected by the sensor roll 6, first,
The plate strain distribution in the plate width direction: f (x, t) is calculated according to the following equation (a).

[0010] f (x, t-τ) = (1 / E) ^{[σ (x) -σ ref (x} ) ]... (B) [However, f (x, t): immediately after rolling the plate width Directional strain distribution (deviation from target value) t: time x: position in the sheet width direction τ: detection delay of tension distribution detection sensor (6) σ ^ref (x): target value of tension distribution E: rolled material (2) Young's modulus]

Then, the shape parameter: Λ _yi (i: the number of actuators used for shape control) is calculated from the obtained f (x, t-τ) value. In addition,
This Λ _yi is a parameter expressing the plate shape defect,
For example, in the case of i = 4, the following equation (b): y = Λ _y1 J ₁ (x) + Λ _y2 J ₂ (x) + Λ _y3 J ₃ (x) + Λ _y4 J ₄ (x) (B) when expressed as), the value of the y is f (x, is t-tau) closest composed as lambda _yi selected. Here, J
_i (x) are arbitrary different functions, for example J _i
When an orthogonal function sequence is selected as (x),

[Equation 1] Then, the value of y should be closest to f (x, t−τ), in other words, the following equation (d):

[Equation 2] Will be chosen to be the minimum.

Thereafter, the shape parameter Λ _yi obtained by the above calculation, the rolling load change value: ΔP and the rolling difference load change value: Δ detected in the load cells 8 and 9 are described.
From q, the disturbance that causes a defective plate shape when applied to the rolling mill 4, that is, the disturbance that should be corrected by the reduction leveling adjustment: d _L , the disturbance that should be corrected by the work roll bending force adjustment: d _WR , the work roll bending difference The disturbance to be corrected by force: d _WRD , and if the intermediate roll is used, the disturbance to be corrected by intermediate roll bending force adjustment: d _IMR is estimated. In estimating the disturbance, the detection delay of the shape parameter Λ _yi is compensated.

Then, based on the obtained estimated disturbance value, each actuator is operated, for example, d
_{For L} , the reduction leveling is adjusted, and d
_The work roll bending force is adjusted for _WR , the work roll bending differential force is adjusted for d _WRD , and the intermediate roll bending force is adjusted for d _IMR . Thus, the shape of the rolled plate is controlled. Further, in adjusting each actuator, a feedback means for adjusting the responsiveness is provided to compensate for the response delay of each actuator.

It should be noted that the disturbance estimation and the actuator adjustment described above are specifically performed according to the following equation (e). However, in this equation (e), ΔF _IMR ^ref is prevented from being output when the intermediate roll bending force is not adjusted. Also,
A _c , A _cd , B _c , B _cd , C _c , D _{c in the} equation (e)
The meaning of and other symbols are as described below.

[Equation 3]

Here, the strip shape control system according to the present invention will be examined more specifically. The input / output relational expression representing the strip shape change of the 6-high rolling mill as shown in FIG. 1 is represented by the following equation (1). Indicated by.

[Equation 4]

However, the definition of Λ _i is as follows. f (x, t) = Λ ₁ · J ₁ (x) + Λ ₂ · J ₂ (x) + Λ ₃ · J ₃ (x) + Λ ₄ · J ₄ (x) + ε _r (x, t) ... ( 2) f (x, t): Plate width direction plate strain distribution (deviation from the target value) x: Plate width direction position (x = 0 is the plate width center) t: Time J _i (x): Arbitrary function Row (i: number of independent actuators). For example, it is as shown by the following expression (3). ε _r (x, t): a component of f (x, t) that is not represented by a linear combination of J _i ΔP: rolling load change Δq: rolling difference load change ΔS _L : rolling leveling deviation (appropriate left / right roll gap difference) ΔF _WR : Work roll bending force deviation (deviation from proper value) ΔF _WRD : Work roll bending differential force deviation (deviation from right and left work roll bending force difference from proper value) ΔF _IMR : Intermediate roll bending Force deviation (deviation from appropriate value) K _ij , K _pj : Constant (determined by strip width, rolled material, etc.)

The above formula (1) is a formula for a 6-high rolling mill equipped with an intermediate roll bender. As independent actuators, ΔS _L , ΔF _WR , ΔF _WRD ,
And ΔF _IMR are considered. ΔS _L = ΔS _L ^c + d _L (4) ΔF _WR = ΔF _WR ^c + d _WR (5) ΔF _WRD = ΔF _WRD ^c + d _WRD (6) ΔF _IMR = ΔF _IMR ^c + d _IMR・ ・ ・ (7) [However, ΔS _L ^c : Reduction leveling change value d _L : Reduction leveling disturbance ΔF _WR ^c : Work roll bending force change value d _WR : Work roll bending force disturbance ΔF _WRD ^c : Work roll bending differential force Change value d _WRD : Work roll bending differential force disturbance ΔF _IMR ^c : Intermediate roll bending force change value d _IMR : Intermediate roll bending force disturbance]

The above d _L , d _WR , d _WRD and d _IMR are
The disturbances are caused by changes in the thermal expansion of the rolls. Further, when the response characteristics of the reduction leveling control, the work roll bending force control, the work roll bending differential force control, and the intermediate roll bending force control are respectively approximated by a first-order lag, they are expressed by the following equations (8) to (11).

[Equation 5]

By the way, parameters representing the shape change:
Assuming that the detection delay of Λ _i is τ (s), the following equation (12)
(15) is established. Λ _y1 = Λ ₁ (t−τ) ・ ・ ・ (12) Λ _y2 = Λ ₂ (t−τ) ・ ・ ・ (13) Λ _y3 = Λ ₃ (t−τ) ・ ・ ・ (14) Λ _y4 = Λ ₄ (t-τ) (15) [where Λ _{yi is a} detectable shape parameter]

When an orthogonal polynomial sequence as shown in the equation (3) is selected as J _i (x), Λ _yi is calculated from the detected plate strain: f (x, t-τ) by the following equation. It is calculated by (16).

[Equation 6]

The above equations (1) to (11) are mathematical model representing the controlled object, and when expressed by a block diagram, they are as shown in FIG.

When the control target of the shape control in the rolling mill is expressed as shown in FIG. 2, the control purpose is expressed as follows. Λ _i = 0 (i = 1 to 4) (17) ε _r (x, t) = 0 (18)

The purpose of control expressed by the equation (17) is to change the reduction leveling (ΔS _L ^ref ), change the work roll bending force (ΔF _WR ^ref ), and change the work roll bending differential force (ΔF). _WRD ^ref ) and change of intermediate roll bending force (ΔF _IMR ^ref ).

Here, ΔS _L ^c , ΔF _WR ^c , ΔF
_The following operations are given to adjust the responsiveness of _WRD ^c and ΔF _IMR ^c .

[Equation 7]

The feedforward control for compensating for the disturbance and achieving the control objective (17) is as follows.

[Equation 8]

Further, from the above equations (19) to (26),
The manipulated variable is given as follows.

[Equation 9]

By the way, in order to realize the equations (29) to (32), the value of the disturbance is required. In the following, we will describe the method of disturbance estimation by the observer.

First, consider the following as a mathematical model of the disturbance to be dealt with.

[Equation 10]

A) d _L , ΔS _L ^c estimation observer 1st line, 3rd line and (4), (8),
From equations (29) and (33), the d _L , ΔS _L ^c estimation observer can be configured as follows.

[Equation 11]

From equations (4) to (7),

[Equation 12]

From the equations (27) and (28),

[Equation 13]

Therefore,

[Equation 14]

From the equations (37) to (39), the following equation (43) can be derived.

[Equation 15]

Here, since Λ _i cannot be measured, a method of forming Λ _{y i} that can be measured will be described below.

First, by modifying the above equation (43), the following equation can be obtained.

[Equation 16]

From equation (41), ΔS _L ^c and d _L
If the estimate of is correct, then

[Equation 17] And from equation (33),

[Equation 18]

Therefore, the above equation (44) is transformed into the following equation (46)
It will be shown as a formula.

[Formula 19]

The expressions (39) and (46) thus obtained
The formula is a control formula that gives the manipulated variable: ΔS _L ^ref .

B) d _WRD, ΔF _WRD ^c estimation observer From the above equations (1), (6), (10), (31) and (35), the d _WRD , ΔF _WRD ^c estimation observer is Can be configured as:

[Equation 20]

Further, such (47), (48), (4
From the equation (9), the following equation (50) can be obtained.

[Equation 21]

From the equations (41) and (35),

[Equation 22]

Therefore,

[Equation 23]

Therefore, the above equations (49) and (51) are control equations that give the manipulated _variable : ΔF _WRD ^ref .

C) d _WR , ΔF _WR ^c estimation observer From the above equations (1), (5), (9), (30) and (34), the d _WR and ΔF _WR ^c estimation observer is as follows. Can be configured as

[Equation 24]

Then, the above (52), (53), (5
From the equation (4), the following equation (58) can be obtained.

[Equation 25]

From the above equations (41) and (34), if ΔF _WR ^c and d _WR are correctly estimated,

[Equation 26] Becomes

Therefore, the following expression (59) can be obtained.

[Equation 27]

Therefore, the expressions (54) and (59) are control expressions that give the manipulated variable: ΔF _WR ^ref .

D) Estimation observer of d _IMR, ΔF _IMR ^c The above (1), (7), (11), (32), and (3)
From the equation (6), the d _IMR and ΔF _IMR ^c estimation observer can be configured as follows.

[Equation 28]

Then, these (60), (61), (6
The following equation (63) can be derived from the equation (2).

[Equation 29]

Where

[Equation 30] Becomes

Therefore, the following equation (64) can be obtained.

[Equation 31]

Therefore, the equations (62) and (64) are control equations that give the manipulated variable: ΔF _IMR ^ref .

As described above in detail, (4
Equations (6), (51), (59), and (64) are observers for estimating the disturbance, and (39), (4)
The equations 9), (54), and (62) are control equations that give the manipulated variable based on the estimated disturbance, and are summarized as follows. The following equation is the same as the above equation (e).

[Equation 32]

[Expression 33]

[Equation 34]

The block diagram of the compensator represented by the above equation is as shown in FIGS. 4 and 5.

In order to confirm the effect of the plate shape control system in the rolling mill according to the present invention, the following Table 1 is given.
~ Under the simulation conditions shown in Table 3, the results of examining the plate strain distribution (I-unit) are shown in Fig. 6. As is clear from the results, when the rolling differential load is used (b), , Compared to (a) when no rolling differential load is used,
It is recognized that the influence of the disturbance on the shape change is eliminated promptly and stably. Tables 1 and 2 below show model parameters and observer gains, and Table 3
Indicates a disturbance that is assumed to be applied stepwise at time 1 (s).

[Table 1]

[Table 2]

[Table 3]

[0057]

As is apparent from the above description, according to the present invention, it is possible to perform highly stable and highly responsive control that copes with a detection delay, and it is possible to expect a stable effect by each actuator responsiveness adjusting function. With this, highly precise control of the plate shape is achieved, and by adjusting the bending differential force, high response control of the third-order component is possible, and if the function of measuring the load change and performing feedforward control is adopted. Therefore, it is possible to perform highly accurate control of the shape change due to the change in rolling load during acceleration / deceleration or the change in rolling difference load. Further, the present invention has a relatively simple compensator structure, can be easily tuned, and can be a system considering mutual interference between the actuators.

[Brief description of drawings]

FIG. 1 is a schematic system diagram of a rolling mill showing an example of implementation of the present invention.

FIG. 2 is a control target block diagram according to an example of the present invention.

FIG. 3 is a diagram showing a remaining portion of the control target block diagram of FIG. 2;

FIG. 4 is a block diagram showing a configuration of a compensator according to an example of the present invention.

5 is a diagram showing a remaining portion of the block diagram of FIG.

FIG. 6 is a graph showing a simulation result of plate strain distribution, in which (a) shows a case where no rolling difference load is used,
(B) shows the case where the rolling difference load is used.

[Explanation of symbols]

 2: Material to be rolled 4: Rolling mill 4a: Work roll 4b: Intermediate roll 4c: Backup roll 6: Tension distribution detection sensor roll 8: Load cell (work side) 9: Load cell (drive side)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication location G05B 13/02 C 7531-3H Q 7531-3H 8315-4E B21B 37/00 116 B (72) Invention Sadaichi Abe 5-11-3 Shimbashi, Minato-ku, Tokyo Sumitomo Light Metal Industry Co., Ltd. (72) Inventor Yukihiro Maekawa 5--11-3 Shimbashi, Minato-ku, Tokyo Sumitomo Light Metal Industry Co., Ltd. (56 ) References JP-A-4-91808 (JP, A) JP-B-56-20087 (JP, B2)

Claims (2)

[Claims] 1. A method for controlling a plate shape in a rolling mill equipped with a reduction leveling adjusting device, a work roll bending force adjusting device, and a work roll bending differential force adjusting device to detect changes in rolling load and changes in rolling differential load. While doing
Detecting the tension distribution in the strip width direction of the rolled strip immediately after rolling, first, calculate the strip strain distribution in the strip width direction based on the tension distribution value, and then use the strip strain distribution to express the strip shape defect Then, from this shape parameter and the detected rolling load change value and the change value of the rolling difference load, while compensating for the detection delay of the shape parameter, the disturbance to be corrected in each of the adjusting devices is calculated. The value is estimated, and based on this estimated value, the respective control devices are operated to control the plate shape of the rolled plate material in the rolling mill while compensating for the response delay of the respective control devices. A plate shape control method in a rolling mill characterized by the above. 2. A method for controlling a plate shape in a rolling mill equipped with a reduction leveling adjusting device, a work roll bending force adjusting device, a work roll bending differential force adjusting device, and an intermediate roll bending force adjusting device, the method comprising: While detecting changes in rolling differential load,
Detecting the tension distribution in the strip width direction of the rolled strip immediately after rolling, first, calculate the strip strain distribution in the strip width direction based on the tension distribution value, and then use the strip strain distribution to express the strip shape defect Then, from this shape parameter and the detected rolling load change value and the change value of the rolling difference load, while compensating for the detection delay of the shape parameter, the disturbance to be corrected in each of the adjusting devices is calculated. The value is estimated, and based on this estimated value, the respective control devices are operated to control the plate shape of the rolled plate material in the rolling mill while compensating for the response delay of the respective control devices. A plate shape control method in a rolling mill characterized by the above.