KR101767810B1 - Plate thickness controller for rolling machine - Google Patents

Abstract

A plate thickness control apparatus for a rolling mill capable of accurately identifying a plasticity coefficient of a rolled material is provided. Therefore, the apparatus for controlling the thickness of the rolling mill has a sintering coefficient identification device for identifying the sintering coefficient indicating the hardness of the rolled material on the basis of the rolling load actual value of the rolling stand to be operated, the roll gap actual value and the constant number of mill. In this configuration, the plasticity coefficient of the rolled material is identified on the basis of data obtained at the rolling stand to be operated. Therefore, the plasticity coefficient of the rolled material can be accurately identified.

Description

TECHNICAL FIELD [0001] The present invention relates to a plate thickness control apparatus for a rolling mill,

The present invention relates to an apparatus for controlling the thickness of a rolling mill.

Patent Document 1 discloses an apparatus for controlling the thickness of a rolling mill. The plate thickness control device identifies the plasticity coefficient of the rolling stand based on the information of the plate thickness of the rolled material measured at the upstream side of the rolling stand, the information of the rolling load of the rolling stand on the upstream side of the rolling stand Is identified. The sheet thickness control apparatus controls the thickness of the rolled material by the rolling stand on the basis of the determined firing coefficient.

Patent Document 1: JP-A-2008-126307

However, in Patent Document 1, the information of the rolling stand on the upstream side of the rolling stand is tracked on the downstream side, and the sintering coefficient of the rolling stand is identified. Therefore, the plasticity coefficient of the rolled material can not be accurately identified.

The present invention has been made to solve the above-described problems. An object of the present invention is to provide a plate thickness control apparatus for a rolling mill which can accurately identify the plasticity coefficient of a rolled material.

The apparatus for controlling the thickness of a rolling mill according to the present invention is provided with a sintering coefficient identification device for identifying a sintering coefficient indicating the hardness of the rolled material on the basis of the rolling load actual value of the rolling stand to be operated, .

According to the present invention, the plasticity coefficient of the rolled material can be accurately identified.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of a rolling mill using a plate thickness control apparatus of a rolling mill according to Embodiment 1 of the present invention. FIG.
2 is a control block diagram of a rolling mill using a sheet thickness control apparatus of a rolling mill in Embodiment 1 of the present invention.
3 is a view for explaining the influence of a constant of whet and a coefficient of plasticity in rolling a rolled material by a rolling mill using a plate thickness control apparatus of a rolling mill in Embodiment 1 of the present invention.
4 is a view for explaining the influence of a constant of whet and a coefficient of plasticity when a rolled material is rolled into a rolling mill using a plate thickness control apparatus of a rolling mill according to Embodiment 1 of the present invention.
5 is a block diagram of a main part of a sheet thickness control apparatus of a rolling mill according to Embodiment 1 of the present invention.
6 is a main part of a control block diagram of a rolling mill using the apparatus for controlling the thickness of a rolling mill according to Embodiment 1 of the present invention.
7 is a view for explaining a table of plasticity coefficients of the apparatus for identifying the sintering coefficient of the apparatus for controlling the thickness of a rolling mill according to the first embodiment of the present invention.
8 is a view for explaining an estimation result of a roll eccentric disturbance by a plate thickness control apparatus of a rolling mill according to Embodiment 1 of the present invention.
9 is a view for explaining an estimation result of a rolling load disturbance by a plate thickness control apparatus of a rolling mill according to Embodiment 1 of the present invention.
10 is a main part of a control block diagram of a plate thickness control apparatus of a rolling mill according to Embodiment 2 of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals. The redundant description of the part is appropriately simplified or omitted.

Embodiment Mode 1.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a configuration diagram of a rolling mill using a plate thickness control apparatus of a rolling mill according to Embodiment 1 of the present invention. FIG.

In Fig. 1, the rolling stand of the hot strip rolling is a 4Hi mill. The rolling stand has a housing (1). In the housing 1, an upper work roll 2a and a lower work roll 2b are provided as rolling rolls. One side of the shaft of the upper work roll 2a is connected to an electric motor (not shown). A work area is secured around the other side of the upper work roll 2a. One side of the shaft of the lower work roll 2b is connected to an electric motor (not shown). A work area is secured around the other side of the lower work roll 2b.

Above the upper work roll 2a, an upper backup roll 3a is provided as a rolling roll. The upper backup roll 3a supports the upper work roll 2a. The upper backup roll 3a is supported on the upper portion of the housing 1. [ One side of the shaft of the upper backup roll 3a is connected to an electric motor (not shown). A work area is secured around the other side of the upper backup roll 3a.

Below the lower work roll 2b, a lower backup roll 3b is provided as a rolling roll. The lower backup roll 3b supports the lower work roll 2b. The lower backup roll 3b is supported at the lower portion of the housing 1. [ One side of the shaft of the lower backup roll 3b is connected to an electric motor (not shown). A work area is secured around the other side of the lower backup roll 3b.

Above the upper backup roll 3a, a press-down device 4 is provided. For example, the screw down device 4 is composed of an electric screw down device. For example, the screw down device 4 is composed of a hydraulic pressure reduction device driven by hydraulic pressure. The hydraulic pressure reduction device can be controlled at a high speed. The screw down device 4 includes a drive side screw down device 4a and an operation side screw down device 4b. The drive side press-down device 4a is provided on one side of the upper backup roll 3a. The opposed push-down device 4b is provided on the other side of the upper backup roll 3a.

A load detector 5 is provided below the lower backup roll 3b. The load detector 5 includes a drive side load detector 5a and an opposed side load detector 5b. The drive side load detector 5a is provided on one side of the lower backup roll 3b. The opposed side load detector 5b is provided on the other side of the upper backup roll 3a.

Below the roll-down device 4, a roll gap detector 6 is provided. The roll gap detector 6 includes a drive side roll gap detector 6a and an opposed side roll gap detector 6b. The drive-side roll gap detector 6a is provided on one side of the upper backup roll 3a. The opaque roll gap detector 6b is provided on the other side of the upper backup roll 3a.

On the output side of the load detector 5, the input side of the rolling load measuring device 7 is connected. On the output side of the roll gap detector 6, the input side of the roll gap meter 8 is connected.

On the output side of the rolling load measuring device 7, the input side of the plate thickness controller 9 is connected. On the output side of the roll gap meter 8, the input side of the plate thickness controller 9 is connected. On the output side of the thickness controller 9, the input side of the roll gap operating means 10 is connected. The output side of the roll gap operating means (10) is connected to the input side of the screw down device (4).

A roll revolution number detector 11 is provided on the lower work roll 2b. On the exit side of the rolling stand, a plate descent system 12 is provided.

The rolled material 3 is formed of a metal. The rolled material 3 is sandwiched between the upper work roll 2a and the lower work roll 2b. As a result, the rolled material 3 is stretched. At this time, the upper backup roll 3a suppresses warpage in the width direction of the upper work roll 2a. The lower backup roll 3b suppresses warpage in the width direction of the lower work roll 2b. The rolling load on the rolled material 3 is received by the housing 1 through the upper work roll 2a, the lower work roll 2b, the upper backup roll 3a and the lower backup roll 3b.

The drive side load detector 5a detects a load applied to one side of the lower backup roll 3b. The opposed load sensor 5b detects a load applied to the other side of the lower backup roll 3b. The rolled load measuring device 7 calculates the sum of the detected value of the drive side load detector 5a and the detected value of the opposed side load detector 5b as a combined load. The rolling load measuring device 7 calculates the difference between the detection value of the drive side load detector 5a and the detection value of the opposed side load detector 5b as a difference load. When a roll bending apparatus (not shown) is provided on the rolling stand, the rolling load measuring device 7 performs calculation when the detected value of the load detector 5 is corrected by the roll bending force.

The roll gap detector 6 does not directly detect the gap (roll gap) between the upper work roll 2a and the lower work roll 2b. The roll gap detector 6 detects the amount by which the press-down device 4 presses the upper backup roll 3a. The roll gap meter 8 calculates the roll gap based on the detection value of the roll gap detector 6. [ At this time, the roll gap measuring device 8 considers the distance relationship between the upper work roll 2a and the lower work roll 2b.

The plate thickness controller 9 adjusts the set value of the roll gap on the basis of the calculated value of the rolling load meter 7 and the calculated value of the roll gap meter 8. [ At this time, the plate thickness controller 9 adjusts the set value of the roll gap using the constant constant (M _C ) and the plasticity coefficient (Q _C ) identified by the identification device not shown in FIG.

The roll gap operating means (10) adjusts the roll gap based on the set value adjusted by the plate thickness controller (9). As a result, the rolled material 3 becomes a desired sheet thickness. The plate thickness of the rolled material 3 is measured by the plate thickness meter 12.

At this time, the roll revolution number detector 11 detects the revolution number of the lower work roll 2b. The roll revolution number detector 11 detects the rotation position of the lower work roll 2b. By this detection, the position in the circumferential direction of the lower work roll 2b is specified. More specifically, when the lower work roll 2b is regarded as a circle viewed from the side, the position of the circumferential reference point is specified. For example, the rotation angle of the reference point with respect to the vertical line is specified.

Next, an example of the plate thickness controller 9 will be described with reference to Fig.

2 is a control block diagram of a rolling mill using a sheet thickness control apparatus of a rolling mill according to Embodiment 1 of the present invention.

In Fig. 2, the rolling process 14 to be controlled is influenced by the constant of whetstone M and the plasticity coefficient Q. Fig. Specifically, the rolling process 14 has a first influence coefficient 14a and a second influence coefficient 14b. The first influence coefficient 14a corresponds to the influence of the roll gap on the rolling load. The first influence coefficient 14a is -MQ / (M + Q). The second influence coefficient 14b corresponds to the influence of the rolling load on the plate thickness. The second influence coefficient 14b is 1 / M.

Rolling process 14, the roll eccentricity disturbance (ΔS _D) are added and the rolling load disturbance (ΔP _D). The roll eccentricity disturbance (ΔS _D ) and the rolling load disturbance (ΔP _D ) can not be directly measured.

The sheet thickness controller 9 performs a monitor AGC 15, a gauge meter AGC 16, an MMC (constant constant variable control) 17, and the like for the rolling process 14.

The first control block 18 calculates the plate thickness measurement value change amount DELTA h ^MES on the basis of the plate thickness actual change amount DELTA h ^ACT measured in the plate thickness gage 12. [ At this time, the first control block 18 considers the conveyance delay time of the rolled material 3 from the rolling stand to the plate girder 12.

Monitor AGC (15) calculates a GM plate thickness change amount of the target value (Δh ^REF) on the basis of the deviation of the product thickness target value changing amount (Δhx ^REF) and the plate thickness measurement variation (Δh ^MES).

In the gauge meter AGC 16, the second control block 16a is displayed using the identified constant constant M _C. In the second control block 16a, a coefficient? ₁ for adjusting the response is added. The GM plate thickness variation amount? H _GM is obtained on the basis of the output of the second control block 16a and the roll gap performance variation amount? S ^ACT .

In the gauge meter AGC 16, the gauge meter plate thickness target value change amount? H _GM ^AIM and the GM plate thickness target value change amount? H ^REF are added together. As a result, the plate thickness target change amount? H _GM ^REF is obtained. The deviation between the plate thickness target value change amount? H _GM ^REF and the GM plate thickness change amount? H _GM is input to the PI controller 16b. PI controller 16b is represented by a proportional gain K _PG , an integral gain K _IG , and a Laplace operator S. Further, the sign S of the roll gap is supposed to be accompanied by suffixes and?, And the Laplace operator S is used alone.

The output of the PI controller 16b is input to the compensation gain 16c. The compensation gain 16c is expressed by the identified constant of constant M _C , the coefficient of plasticity Q _C , and the coefficients α ₁ and α ₂ for adjusting the response. The compensation gain 16c calculates a roll gap command value DELTA S ^SET . At this time, the compensation gain 16c normalizes the operation output. In this case, adjustment of the PI controller 16b becomes unnecessary even if the constant M of the control object, the plasticity coefficient Q, and the coefficients? ₁ and? ₂ change.

The MMC 17 requires a fast response to the screw down device 4. Therefore, when the press-down device 4 is not a hydraulic pressure reduction device, the MMC 17 is not applied.

In the MMC 17, the third control block 17a is displayed using the identified constant M _C. The MMC 17 can adjust the response by adjusting the coefficient? ₂ of the third control block 17a. For example, if the coefficient? ₂ is increased, the response speeds up.

In the MMC 17, the hydraulic pressure reduction response 17b corresponds to the response of the hydraulic pressure reduction device. The hydraulic pressure drop response 17b is determined based on the value obtained by superimposing the output of the compensation gain 16c and the output of the third control block 17a. As a result, the roll gap is adjusted.

Next, the influence of the constant constant M on the plate thickness of the rolled material 3 and the plasticity factor Q will be described with reference to Fig.

3 is a view for explaining the influence of the constant of whet and the coefficient of plasticity when the rolled material is rolled into a rolling mill using the plate thickness control apparatus of the rolling mill according to the first embodiment of the present invention.

In Fig. 3, the wheat curve represents the aspect of wheat elongation. The mill elongation is caused by the housing 1 or the like receiving a large rolling load from the rolled material 3. If the rolling load is large, the mill elongation also becomes large. The wheat curve is approximated by a quadratic curve or a cubic curve. Mill curves can be measured.

The constant of wheat (M) represents the ratio of the elongation of the mill. The constant of wheat (M) is indicated by the slope of the wheat curve at the specified rolling load. For example, when the rolling load is 600 (kN) and the elongation is 1 (mm), the constant of constant (M) is 600 (kN / mm).

In Fig. 3, the firing curve is obtained by plotting the change of the rolling load when the thickness of the rolled material 3 changes. When the strength of the rolled material 3 is high, the firing curve rises. When the temperature of the rolled material 3 is low, the firing curve rises. The firing curve can not be directly measured.

The plasticity coefficient Q indicates the hardness of the rolled material 3. The plasticity coefficient Q is expressed as a slope of a sintering curve at a specified rolling load.

In Fig. 3, the initial state is indicated by the intersection (a) of the mill curve and the firing curve. At this time, the roll gap is S _G. The plate thickness of the rolled material 3 at the inlet side of the rolling stand is H. The plate thickness of the rolled material 3 on the exit side of the rolling stand is h.

When the temperature of the rolled material 3 falls, the firing curve rises. The state at this time is indicated by the intersection (b) between the wheat curve and the firing curve. As a result, the thickness of the rolled material 3 on the outlet side increases to h +? H. Changing the roll gap by a sheet thickness control in S _G S _G from _G -ΔS, it moves the mill curve to the left. The state at this time is indicated by the intersection (c) between the wheat curve and the firing curve. As a result, the plate thickness of the rolled material 3 on the exit side becomes thinner than h +? H.

Next, details of the influence of the constant constant M and the plasticity coefficient Q will be described with reference to Fig.

4 is a view for explaining the influence of the constant of whet and the coefficient of plasticity when the rolled material 3 is rolled into a rolling mill using the apparatus for controlling the thickness of the rolling mill according to the first embodiment of the present invention.

4, the constant constant M is expressed by the following equation (1).

[Equation 1]

Considering the relational expression established by the triangle in Fig. 4, tan? Is expressed by the following expression (2).

[Equation 2]

(1) and (2), a gauge metric equation is obtained. The gauge meter expression is expressed by the following expression (3).

[Equation 3]

In Fig. 4, the plasticity coefficient Q is expressed by the following equation (4).

[Equation 4]

Considering the relational expression established by the triangle in Fig. 4, the plasticity coefficient Q is expressed by the following equation (5).

[Equation 5]

The relationship between the plasticity coefficient Q and the plate thickness H of the rolled material 3 on the inlet side can be obtained by the formulas (4) and (5). The relationship between the plasticity coefficient Q and the plate thickness H of the rolled material 3 on the inlet side is expressed by the following equation (6).

[Equation 6]

In Figure 4, the open ΔS _G as the roll gap, the state is moved from the point (A) point (B). At this time, the constant constant M is expressed by the following equation (7).

[Equation 7]

(7), the change amount? P of the rolling load is expressed by the following equation (8).

[Equation 8]

The plasticity coefficient Q is expressed by the following equation (9).

[Equation 9]

(9), the change amount DELTA P of the rolling load is expressed by the following equation (10).

[Equation 10]

The change amount? H of the thickness of the rolled material 3 is expressed by the following formula (11) by the formulas (8) and (10).

[Equation 11]

(10) and (11), the change amount? P of the rolling load is expressed by the following equation (12).

[Equation 12]

(3), the change amount? H of the plate thickness is expressed by the following expression (13).

[Equation 13]

Next, the identification device will be described with reference to Fig.

5 is a block diagram of a main part of a sheet thickness control apparatus of a rolling mill according to Embodiment 1 of the present invention.

As shown in Fig. 5, the identification apparatus includes a wheat integer identification device 19 and a firing coefficient identification device 20. As shown in Fig.

Based on the rolling load history variation amount AP ^ACT , the roll gap performance variation amount DELTA S ^ACT , the plate thickness actual variation amount DELTA h ^ACT and the roll rotation actual performance value ₁ , (M ^ID ). Wheat integer (M ^ID) is input to the mill constant _(C M) of the gauge-meter (AGC16), MMC (17) . In this case, the constant of wheat (M _C ) may be the constant of wheat (M ^MES ) identified by a separate method by a kiss roll test or the like.

The firing coefficient identification device 20 calculates the firing coefficient Q ^ID based on the rolling load actual change amount AP ^ACT , the roll gap actual change amount? S ^ACT , the roll rotation actual value? ₂ , . In this case, the identified constant constant is selected from a constant constant (M ^ID ) or constant constant (M ^MES ). The plasticity coefficient (Q ^ID ) is input to the plasticity coefficient (Q _C ) of the gauge meter AGC (16).

Next, a method of calculating the constant constant (M ^ID ) and the plasticity coefficient (Q ^ID ) will be described with reference to Fig.

6 is a main part of a control block diagram of a rolling mill using the apparatus for controlling the thickness of a rolling mill according to Embodiment 1 of the present invention.

In Fig. 6, the noise N _h is applied to the rolling process 14 of Fig. 2, and the plate thickness actual change amount? _H ^ACT is observed.

6, the change amount? _H of the thickness of the rolled material is expressed by the following equation (14) using the error e ₁ by the noise N _h .

[Equation 14]

The roll eccentricity disturbance? S _D is caused by the structure of the rolling roll, the accuracy of the polishing of the rolling roll, and the like. For example, in a support roll having an oil bearing, when a key groove receives a rolling load of several hundred tons to several thousand tons, the shaft moves up and down. By this movement, a roll eccentric disturbance? S _D is generated. For example, in a rolling roll without a key groove, a roll eccentric disturbance? S _D is generated due to a deviation of thermal expansion or the like.

Roll eccentricity disturbance (ΔS _D), it can be thought of as a periodic disturbance in synchronization with the rotation period of the upper back-up roll (3a) and the lower back-up roll (3b). During rolling, the rolling speed changes. Therefore, the roll period of the eccentricity disturbance (ΔS _D) is changed by time. The roll eccentricity disturbance ΔS _D is a value obtained by subtracting the rotational angle φ ₁ (0 ° to 360 °) of the upper work roll 2a, the lower work roll 2b, the upper backup roll 3 a and the lower backup roll 3b, In a predetermined period.

In this case, the roll eccentricity disturbance (ΔS _D) is, and is approximated by the k difference Fourier series. Specifically, the roll eccentricity disturbance (ΔS _D) is represented by the following 15 formula.

[Equation 15]

(14) is modified and the equation (15) is used, the following equation (16) is obtained.

[Equation 16]

(16) expresses the relationship of each variable at any time of the rolled material 3, and generally, a plurality of data sets are obtained from the rolled material 3, and each data set is represented by (16 ). Parameters such as the constant constant M can be obtained by estimating the most reliable parameters satisfying a plurality of equations (16).

For example, when the resultant is, N pieces of data sets for a single rolled plate (3), the rolling load performance variation (ΔP ^ACT), the roll gap performance variation (ΔS ^ACT), the thickness measured value change (Δh ^ACT), the roll N rotational angle actual values (? ₁ ) are obtained.

Applying N data to Eq. (16) yields N simultaneous equations. In order to summarize them, we define variables represented by vectors or matrices.

The data set of Δh-ΔS is, and as a column vector (Y ₁₎ that contains the elements of the N Δh -ΔS ^{ACT ACT.} [? P I cos? ₁ sin? ₁ ... _{cos (kφ 1) sin (kφ} 1) data sets - is, according to the N row and first column matrix (I _NX1), the N φ ₁ containing only a column vector, elements 1 containing the elements of the N ΔP ^ACT sin , and a matrix (X ₁ ) of N rows and 2k columns including the value of cos. (1 / M a _{S 0} a _{S 1} b _S1 ) shown in the first term of the right side of the equation (16). a _Sk b _Sk ] ^T is set as a column vector (θ ₁ ).

These are summarized, and the following equation (17) is obtained. Here, the data set of the error due to noise e ₁ is represented by a vector E ₁ .

[Equation 17]

(17), an optimization technique is used. Several optimization methods have been proposed, but here, examples are identified by the most general least squares method.

The least squares solution of? ₁ is expressed by the following equation (18).

[Equation 18]

The whell constant identification device 19 calculates the wheat constant M ^ID using the equation (18). At this time, the wheat number identification device 19 compensates for the delay time caused by the conveyance between the rolling stand and the plate descent system 12 with respect to the plate thickness actual value change amount DELTA h ^ACT . By compensating the art, the thickness change amount actual performance value (Δh ^ACT) will be synchronized with the rolling load performance variation (ΔP ^ACT), a roll gap change in performance (ΔS ^ACT).

The constant of constant M depends largely on the mechanical characteristics of the housing 1, the upper work roll 2a, the lower work roll 2b, the upper backup roll 3a and the lower backup roll 3b. For this reason, the constant constant M ^ID is calculated for each rolling stand.

For example, it is assumed that the data of the rolling stand is stored, and the mill constant is identified as M [1] (stored) (kN / mm). The data of the same rolling stand is obtained and it is assumed that the mill constant is identified as M [1] (raw) (kN / mm). In this case, the wheat integer identification device 19 stores M [1] (raw). In the plate thickness control, a new smoothed whell constant is used. The smoothing suppresses the destabilization result of the identification result due to the deviation of the data. The new constant of wheat is expressed by the following equation (19).

[Expression 19]

(19), a is the smoothing gain. a is set to a value from 0 to 1. If a is increased, the wheat constant M (1) (raw) is easily reflected in the new wheat constant.

In the first rolled material 3 immediately after the upper work roll 2a, the lower work roll 2b or the upper backup roll 3a and the lower backup roll 3b are exchanged, There are also a few cases. Therefore, immediately after the exchange, the wheat integer identification device 19 increases the ratio of M [1] (raw). In this case, the new whell constant is expressed by the following equation (20) using the smoothing gain A larger than a.

[Equation 20]

Several rolled materials 3 are rolled immediately after the replacement of the upper side work roll 2a, the lower side work roll 2b or the upper side backup roll 3a and the lower side backup roll 3b, May be continuously used. In this case, the result of the identification after the replacement of the upper work roll 2a, the lower work roll 2b or the upper backup roll 3a and the lower backup roll 3b is easily reflected.

Next, a method of identifying the plasticity coefficient (Q) will be described below. The basic idea is the same as the constant constant (M) shown above.

6, the amount of change (ΔP) in the rolling load by using the error (e ₂₎ by the noise (N _h) is expressed by the following 21 formula.

[Equation 21]

(21), the following equation (22) is obtained.

[Equation 22]

In this case, w is defined by the following formula (23).

[Equation 23]

When the rolled material 3 is a slab before it is rolled, the slab is placed in a heating furnace (not shown). In the heating furnace, a plurality of skids (not shown) are provided. The plurality of skids are arranged at substantially equal intervals. The plurality of skids support the slab. The inside of a plurality of skids is cooled with water. Therefore, in the slab, the temperature of the portion contacting the skid is lowered. This part is called a skid mark.

The rolling load disturbance (DELTA _PD ) can be regarded as a periodic disturbance synchronized with the skid mark. During rolling, the rolling speed changes. Therefore, the cycle of the rolling load disturbance (DELTA _PD ) varies with time. The rolled load disturbance DELTA _PD is set such that the rotation angle phi ₂ (0 to 360 degrees) of the upper work roll 2a, the lower work roll 2b, the upper backup roll 3a and the lower backup roll 3b, In a predetermined period.

In this case, w is approximated by a k-th order Fourier series. Concretely, w is expressed by the following expression (24).

[Equation 24]

(25) is obtained by modifying the equation (22) and using the equations (23) and (24).

[Equation 25]

When N data obtained from the rolled material 3 is applied to Eq. (25), N simultaneous equations are obtained. In order to summarize them, we define the variables represented by vectors or matrices as follows.

The data set of? P is a column vector (Y ₂ ) including elements of? P ^ACT . [? S I cos? ₂ sin? ₂ ... _{cos (kφ 2) sin (kφ} 2) the data set of] is the column containing an element of the N number of ΔS ^ACT vector, N row and first column matrix element are made of only one (I _NX1), by the N φ ₂ sin and by N column matrix line 2k (X ₂₎ that contains the value of cos. (-MQ / (M + Q) a _w0 a _w1 b _w1 appearing in the first term of the right side of the equation (25) a _wk b _wk ] ^T is the column vector ( ₂ ).

These are summarized, and the following equation (26) is obtained. Here, the data set of the error (e ₂ ) due to noise is represented by a vector (E ₂ ).

[Equation 26]

(26) is solved by the least square method in the same manner as in the expression (17). The least square solution of? ₂ is expressed by the following equation (27).

[Equation 27]

The plasticity coefficient identification device 20 calculates the plasticity coefficient (Q ^ID ) using the equation (27). In this case, the constant constant M is selected from a constant constant (M ^ID ) or constant constant (M ^MES ).

The identification of the plasticity coefficient (Q) is carried out at a timing at which any number of data is accumulated. The firing coefficient identification device 20 has a table of the plasticity coefficient, with the rolling stand number, the steel grade, the plate thickness classification, and the temperature range as the division indexes. Each cell in the table is called a lot. The following information (A) to (D) is associated with each lot.

(A) the number of rolled materials 3 corresponding to the cell

(B) the ID number of each rolled material (3) and the rolling date and time

(C) Data necessary for identification of the plasticity coefficient obtained from each material

(D) ID number of the rolled material (3) identified last time

The plasticity coefficient identification device 20 calculates the plasticity coefficient Q ^ID at the timing (a) or timing (b) using the information of (A) to (D).

(a) The plasticity coefficient (Q ^ID ) is calculated at the time when a predetermined number or more of new data is accumulated.

(b) Each time the data of the rolled material 3 contained in the lot is taken, the plasticity coefficient (Q ^ID ) is calculated for the data of the lot.

In the case of the timing (a), the engineer may see the accumulated data number and judge it appropriately. The plasticity coefficient (Q ^ID ) may be automatically calculated when the number of data becomes equal to or greater than the number of data.

In the case of timing (b), data is stored in a lot (rolling stand, steel type, plate thickness, temperature range) and the plasticity coefficient is Q [1, 2, 3, 4] . It is assumed that the data of the rolled material 3 under the same condition as the lot is obtained and that the plasticity coefficient is identified as Q [1, 2, 3, 4] (raw) (kN / mm). The firing coefficient identification device 20 stores the smoothed new plasticity coefficient in the lot. In the plate thickness control, a new smoothed coefficient of plasticity is used. The smoothing suppresses the destabilization result of the identification result due to the deviation of the data. The new plasticity coefficient is expressed by the following equation (27).

[Equation 28]

(28), b is the smoothing gain. b is set to a value from 0 to 1. If b is increased, the plasticity coefficient (Q) [1, 2, 3, 4] (raw) is easily reflected in the new constant of wheat.

The smoothing can also be applied to the timing (a). A smoothing different from the equation (28) may be applied.

Next, the table of the plasticity coefficient Q will be described with reference to Fig.

7 is a diagram for explaining a table of plasticity coefficients of the apparatus for identifying the sintering coefficient of the apparatus for controlling the thickness of a rolling mill according to the first embodiment of the present invention.

In Fig. 7, if a rolling stand, a steel grade, a plate thickness classification, and a temperature range are specified, only one lot is designated. As a result, the lot is distinguishable from other lots.

Next, the validity of the constant of denomination (M ^ID ) and the plasticity coefficient (Q ^ID ) will be described with reference to Figs. 8 and 9. Fig.

8 is a view for explaining an estimation result of a roll eccentric disturbance by a plate thickness control apparatus of a rolling mill according to Embodiment 1 of the present invention. 9 is a view for explaining the estimation result of the rolling load disturbance by the plate thickness control apparatus of the rolling mill in Embodiment 1 of the present invention.

As shown in Fig. 8, the estimated value of the roll eccentric disturbance almost coincides with the value of the actual disturbance. As shown in Fig. 9, the estimated value of the rolling load disturbance substantially coincides with the actual disturbance value. For this reason, the wheat constant M ^ID and the plasticity coefficient Q ^ID are accurately calculated.

According to the first embodiment described above, the firing coefficient identification device 20 identifies the firing coefficient of the rolled material 3 on the basis of the rolling load actual value of the rolling stand to be operated, the roll gap actual value and the constant of whetting . Therefore, the plasticity coefficient of the rolled material 3 can be accurately identified.

Further, the wheat number identification device 19 identifies the milling constant of the rolling stand on the basis of the rolling load actual value of the rolling stand to be controlled, the roll gap actual value, and the thickness of the rolled material on the downstream side of the rolling stand. Therefore, the milling constant of the rolling stand can be accurately identified.

Further, the whell number identification device 19 identifies the constant of the rolling stand on the basis of the rotational position of the rolling roll of the rolling stand concerned. More specifically, the wheat integer identification device 19 calculates the wheat constant using the equation (18). Therefore, the milling constant of the rolling stand can be more accurately identified.

Further, the whell number identification device 19 identifies the whell constant every time the data of one rolled material 3 is obtained with respect to the rolling stand, and smoothens it to find the whell number that has been identified in the past. When the rolling roll of the rolling stand is exchanged, the constant number identification device 19 makes the rate of using the latest identification data higher than usual. Therefore, the milling constant of the rolling stand can be more accurately identified.

Further, the firing coefficient identification device 20 identifies the firing coefficient of the rolled material 3 based on the constant of wheat obtained by the kiss roll test. Therefore, the plasticity coefficient of the rolled material 3 can be more accurately identified.

The firing coefficient identification device 20 identifies the firing coefficient of the rolled material 3 based on the rotational position of the rolling roll of the rolling stand. Specifically, the plasticity index identification device 20 calculates the plasticity coefficient using the equation (26). Therefore, the plasticity coefficient of the rolled material 3 can be more accurately identified.

Further, the plasticity coefficient identification device 20 identifies the plasticity coefficient of the rolled material 3 by using previously collected data. Therefore, the plasticity coefficient of the rolled material 3 can be calculated using past data.

The plasticity coefficient identification device 20 identifies the plasticity coefficient of the rolled material 3 when a predetermined number of data are accumulated for each lot divided into the same or similar steel types, plate thicknesses, and rolling temperature ranges. Therefore, the plasticity coefficient of the rolled material 3 can be calculated more accurately.

The firing coefficient identification device 20 identifies the plasticity coefficient of the rolled material 3 every time data is stored in a lot classified into the same or similar steel grade, plate thickness, and rolling temperature range. Therefore, the plasticity coefficient of the rolled material 3 can be modified by the latest data.

When the plate descent system 12 is not provided on the downstream side of the rolling stand, the plate thickness of the rolled plate 3 on the exit side of the rolling stand may be determined using the mass flow constant rule. The mass flow constant law is expressed by the following equation (29).

[Equation 29]

(29), the subscript X corresponds to the position immediately below the plateau 12, assuming that the plateau 12 is provided. The subscript i corresponds to the rolling stand number in question. h is the thickness of the rolled material 3. V is the velocity of the rolled material 3. f is the advanced rate. The advanced rate (f) is calculated from the rolling model. V _Ri is measured from the peripheral speed of the rolling roll of the rolling stand.

Embodiment 2:

10 is a main part of a control block diagram of a plate thickness control apparatus of a rolling mill in Embodiment 2 of the present invention. The same or similar parts as those of the first embodiment are denoted by the same reference numerals, and a description thereof will be omitted.

Sheet thickness control in the second embodiment 9, by using a (ΔS _D) the identified roll eccentricity disturbance to improve the control performance. Specifically, the roll gap operating means 10 adjusts the roll gap in a direction opposite to the identified roll eccentric disturbance? S _D. By this adjustment, the roll eccentric disturbance is erased.

In reality, there is an error in specifying the position of the rolling roll, or the response of the hydraulic pressure reduction device is delayed. Therefore, when the roll eccentric disturbance is compensated by 100%, an abnormality such as hunting of control may occur. For this reason, the adjustment gain K _SD is introduced.

In Figure 10, the estimated roll eccentricity disturbance (ΔS _D), is multiplied by the adjustment gain (K _SD), a roll eccentricity compensation amount (ΔS _D ^REF) is calculated. The roll eccentricity compensation amount? SD ^REF is added to the roll gap command value? ^SET .

According to the second embodiment described above, the roll gap operating means 10 adjusts the roll gap of the rolling stand so as to reduce the influence of the roll eccentric disturbance. Therefore, the thickness of the rolled material 3 can be controlled with high precision.

The plate thickness control apparatus of the first and second embodiments may be applied to a mill other than a 4Hi mill. For example, the plate thickness control apparatus may be applied to a 2Hi mill comprising an upper work roll 2a and a lower work roll 2b. The sheet thickness control apparatus may be applied to a 6Hi mill in which an intermediate roll is added to a 4Hi mill.

[Industrial Availability]

INDUSTRIAL APPLICABILITY As described above, the plate thickness control apparatus of the rolling mill according to the present invention can be used for accurately identifying the plasticity coefficient of the rolled material.

1: housing 2a: upper work roll
2b: Lower work roll 3a: Upper backup roll
3b: lower backup roll 4:
4a: drive-side pressing device 4b: ope-side pressing device
5: Load detector 5a: Drive side load detector
5b: Oppee side load detector 6: Roll gap detector
6a: drive side roll gap detector 6b: Oppe side roll gap detector
7: Rolling load measuring instrument 8: Roll gap measuring instrument
9: plate thickness controller 10: roll gap operating means
11: Roll speed detector 12:
13: Rolled material 14: Rolling process
14a: first influence coefficient 14b: second influence coefficient
15: Monitor AGC 16: Gauge meter AGC
16a: second control block 16b: PI controller
16c: compensation gain 17: MMC
17a: third control block 17b: hydraulic pressure reduction response
18: First control block 19: Mill constant identification device
20: Plasticity identification device

Claims (13)

A sintering coefficient identification device for identifying the sintering coefficient indicating the hardness of the rolled material based on the rolling load actual value of the rolling stand to be operated, the roll gap actual value,
And a mill constant identification device for identifying the mill constant of the rolling stand on the basis of the rolling load actual value of the rolling stand, the rolling gap actual value, and the thickness of the rolled material on the downstream side of the rolling stand,
Wherein said plasticity factor identification device identifies said plasticity factor based on a constant of wheat identified by said whell constant identification device,
The wheat number identification device is configured to compensate for the delay time by the conveyance from the rolling stand to the plate descender for measuring the plate thickness of the rolled material with respect to the plate thickness of the rolled material on the downstream side of the rolling stand, Obtains a roll gap performance change amount on the basis of a change amount from the normal value of the roll gap of the rolling stand and obtains a rolling load achievement change amount based on a deviation between a measured value of the rolling load of the rolling stand and a preset value, Wherein the mill uniform is identified by applying an optimization method by a least squares method to an equation including a thickness measurement change amount, the roll gap performance change amount, a rolling load achievement change amount, a rolling position of a rolling roll, A device for controlling the thickness of a rolling mill. delete delete delete delete The method according to claim 1,
The mill constant identification device identifies the milling constant of the rolling stand each time data of one rolled material is obtained with respect to the rolling stand and smoothes the milling constant of the rolling stand so that the rolling roll of the rolling stand exchanges And the rate of using the latest identification data is made higher than usual. delete The method according to claim 1,
Wherein the sintering coefficient identification device identifies the sintering coefficient of the rolled material based on the rotational position of the rolling roll of the rolling stand. And a sintering coefficient identification device for identifying a sintering coefficient indicating the hardness of the rolled material on the basis of the rolling load actual value, rolling gap actual value and constant number of mills of the rolling stand to be operated,
The firing coefficient identification device determines the change amount of the rolling load performance on the basis of the deviation between the measured value of the rolling load of the rolling stand and a preset value and calculates a variation amount of roll gap performance on the basis of the change amount from the normal value of the roll gap of the rolling stand And the plasticity coefficient of the rolled material is determined by applying an optimization method by a least squares method to the equation including the change amount of the rolling load performance, the roll gap performance change amount, the rolling position of the rolling roll, the constant of whetstone and the plasticity coefficient And a control unit for controlling the thickness of the rolling mill. 10. The method of claim 1 or 9,
Wherein the plasticity coefficient identification device identifies the plasticity coefficient of the rolled material by using previously collected data. 10. The method of claim 1 or 9,
Wherein the plasticity coefficient identification device identifies the plasticity coefficient of the rolled material when a predetermined number of data are stored for each lot divided into the same or similar steel types, controller. 10. The method of claim 1 or 9,
Wherein the plasticity coefficient identification device identifies the plasticity coefficient of the rolled material each time data is accumulated in a lot classified into the same or similar steel grade, plate thickness, and rolling temperature range. 10. The method of claim 1 or 9,
And a roll gap operating means for estimating a roll eccentric disturbance caused by the eccentricity of the rolling roll of the rolling stand and adjusting a roll gap of the rolling stand so as to reduce the influence of the eccentric roll disturbance, Thickness control device.

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