JP3085527B2 - Method for estimating delivery side plate thickness of rolling mill, method and apparatus for controlling rolling mill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a multi-high rolling mill, and more particularly to a method for estimating a sheet thickness immediately below a roll and a sheet thickness control method using the same.

[0002]

2. Description of the Related Art In the control of the thickness of a tandem rolling mill, feedback control is performed for each stand so that the deviation between the thickness and the set value detected by the exit thickness gauge of each stand is set to zero. Also in the rolling control of the multivariable control, for example, in a tandem rolling mill described in Compute Roll No. 27 (1989), the state quantity includes the rolling position, the forward tension, and the number of rolls, and the control quantity includes the sheet thickness, the sheet width, and the rolling load. And a control model using torque and a plate thickness as a control amount directly uses a value measured by a delivery side thickness gauge.

[0003]

As described above, the thickness control of the conventional rolling mill uses the measurement value obtained by the exit thickness gauge. However, the thickness of the sheet thickness measured by the exit thickness gauge is a large waste time (about 5 times) while the rolled material moves from immediately below the roll to the thickness gauge.
00 ms). For this reason, the control output based on the plate thickness just below the roll is delayed by this dead time, and there is a problem that the plate thickness accuracy with respect to the disturbance of the base material is reduced and the product quality is deteriorated.

An object of the present invention is to provide a method of estimating a thickness of a rolling mill for estimating a thickness immediately below a roll in a rolling mill including a plurality of stands with high accuracy, and a rolling control device using the estimated value. It is in.

[0005]

According to the present invention, there is provided a method for estimating the exit plate thickness of a rolling mill comprising a plurality of stands with i = 1 to n at a sampling cycle, comprising the steps of: the side plates speed vei measures, measures the plate speed voi out outlet side of the i stands, the thickness at delivery side immediately below the roll of i stand you estimated in real time in accordance with constant mass flow law from those measurements.

[0006] Then , at the time when the estimated thickness of the plate portion just below the roll on the delivery side reaches the thickness gauge on the delivery side of the i-stand,
A difference between the estimated sheet thickness immediately below the roll and the measured value obtained by the sheet thickness gauge on the output side is obtained by filtering, an offset amount is obtained, and the offset amount is added to correct the estimated value of the next cycle. And

Further, the present invention provides a method for controlling a rolling mill in which a feed-out sheet thickness is feedback-controlled at a predetermined cycle for each stand so as to become a set value. The thickness of the sheet immediately below the roll is estimated from these measured values in accordance with the rule of constant mass flow, and feedback control is performed so as to eliminate the error between the sheet thickness immediately below the roll and the set value.

[0008] Alternatively, a detecting device for detecting a plurality of actual values of a plurality of state quantities and a plurality of control amounts of a rolling mill including a plurality of stands at predetermined intervals, and an operating point and a target set value determined by a setup controller. And a rolling mill control device provided with a DDC control device for controlling so as to eliminate the error of the actual value, wherein the DDC control device performs a feedback control as a state amount using a rolling position, a rear tension and a roll speed of a front stand as a state quantity. Means, a control amount feedback control means for feedback-controlling the output side plate thickness and the rear tension as a control amount, and estimating the output side plate thickness directly below the roll from the measured values of the input side plate thickness, the input side plate speed and the output side plate speed in accordance with the constant law of mass flow. And an observation device that sets the outlet plate thickness immediately below the roll to the outlet plate thickness.

Further, the observation device is provided with a calculating means for calculating the outlet plate thickness immediately below the roll in accordance with a constant law of mass flow, and a waste from the actual change of the outlet plate thickness immediately below the roll to the measurement by the outlet plate thickness gauge. After a time corresponding to the time, there is provided an offset detecting means for subtracting the exit side sheet thickness just below the roll and the exit side thickness gauge, filtering the difference value and feeding back the difference value to the arithmetic means. .

[0010] According to the configuration of the present invention, the output side sheet thickness, which is feedback-controlled as the control amount of the rolling mill, is used by estimating the sheet thickness immediately below the roll, so that the change in the sheet thickness is measured by the output side thickness gauge. In addition, it is possible to estimate the actual thickness change in real time, and to respond to disturbances such as fluctuations in the thickness of the inlet side with high response. In addition, the amount of offset that changes due to the temperature and wear of the roll is obtained and fed back,
Since the thickness under the roll calculated by the constant law of mass flow is corrected, the accuracy of the estimated value is high, and the accuracy of controlling the thickness of the rolling mill is improved, thereby improving the product quality.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below by applying it to a rolling control system that performs multivariable control. FIG. 2 is a configuration diagram showing a rolling control system to be applied.
The rolling mill 1 receives a command from the control device 2 and operates with desired accuracy. The control device 2 periodically detects the actual value such as the state quantity or the control amount indicating the operation state of the rolling mill 1 by the detection device 3, generates an operation command according to the rolling state, and operates the actuator 8.

The rolling mill has a strong non-linearity and cannot apply the modern control theory based on the linear control theory as it is. Therefore, the control device 2 includes a setup control system 4 that determines an operation point that can be linearly approximated according to the operation state of the rolling mill 1. The rolling model 6 is used to determine an operating point.

The DDC controller 5 sets an operating point or a set-up value which is a target value of a control amount or an operation amount by the set-up control system 4, and makes a deviation between the set-up value and an actual value from the detecting device 3 zero. Works like that.

The observation device 7 generally uses an output from the detection device 3 to estimate a state quantity that is necessary for control and cannot be directly measured. In this embodiment, the thickness of the delivery side plate immediately below the roll is estimated, and the details will be described later, and constitute a characteristic part of the present invention.

FIG. 3 shows a stand configuration of the rolling mill 1. The stand of the rolling mill 1 includes a pair of work rolls 10 facing each other,
It comprises an intermediate roll 11 and a backup roll 12. A rolling device 13 is provided on the backup roll 12, and by controlling the rolling position thereof, the interval (roll gap) between the work rolls 10 in contact with the intermediate roll 11 changes, and the thickness and tension of the rolled material 14 change. Can be done. A roll driving device (electric motor) 16 is connected to a shaft of the work roll 10 via a gear device 15. The actuator 8 is configured by the pressing device 13 and the roll driving device 16.

FIG. 4 shows the relationship between the work roll 10 and the rolled material 14. The rolled material 14 moves from left to right in FIG.
The thickness H of the rolled material 14 on the incoming side, the thickness h on the outgoing side, the interval S between the work rolls, and the load P applied to the work rolls. Of these quantities, the physical relationship of the rolling load was expressed (Equation 1).
Is an approximate expression of Hill shown in FIG. This approximate expression is an expression obtained by an experiment.

[0017]

(Equation 1)

[0018]

(Equation 2)

In the expression (1), the subscript i indicates the physical quantity of the i-stand in the multi-high rolling mill system.

The friction correction term in equation (1) is represented by equation (2). On the other hand, the gauge meter type is the following formula (Equation 3)
It is represented by The rolling model 6 is basically expressed by (Equation 1)
(Equation 3).

[0021]

(Equation 3)

FIG. 5 is an explanatory diagram showing the relationship between (Equation 1) and (Equation 3). The vertical axis indicates the rolling load P, and the horizontal axis indicates the rolling position and the sheet thickness. The intersection of the load equation (Equation 1) with the horizontal axis plate thickness indicates the thickness of the entry side (base material) of the rolling mill. The intersection of the load equation (Equation 1) and the gauge meter equation (Equation 3) is the operating point, the horizontal axis position of the operating point is the exit side plate thickness h, and the vertical axis position is the rolling load P at that time.

The setup control system 4 determines the intersection of the load equation and the gauge meter equation under various rolling conditions. As a specific method of calculating the operating point, there is Newton's method of repeatedly obtaining a numerical solution.

When the thickness of the base material changes from H0 to H1, as shown in FIG. 6, the operating points of the rolling load type and the gauge meter type change, and the exit side thickness changes from h0 to h1.
1, the rolling load changes from P0 to P1. as a result,
The plate thickness deviates from the target value h.

Therefore, as shown in FIG. 7, the rolling position S of the rolling mill is moved to control the thickness of the rolling mill so that the thickness can be adjusted to a desired accuracy. At that time, the operation command is ΔS, and the pressing position of the pressing device 13 is controlled from S1 to S. As a result, the gauge meter type moves in parallel from the dotted line position to the solid line position, and the intersection with the load type moves from h1, the rolling load P1 to the sheet thickness h, and the rolling load P.

Thus, the setup control system 4 determines the operating point, which is the intersection of the rolling load type and the gauge meter type.
The DDC controller 5 controls so as to eliminate the deviation from the operating point.

FIG. 1 is a block diagram of an embodiment of the present invention, showing a rolling mill control device configured in an optimum servo control system. The rolling mill system 1 including a plurality of stands operates with desired accuracy in response to an operation command (operation amount) of the command generation mechanism 24.

The difference mechanism 25 and the proportional mechanism 20 constitute a state feedback control system. That is, the difference between the state quantity detected by the detection device 3 and the setup value of the operating point given by the setup control system 4 is obtained by the difference mechanism 25, and the difference is multiplied by the proportional gain by the proportional mechanism 20 to obtain the state deviation command. Generate components. In the present embodiment, the rolling position S, the rear tension τb, and the roll speed VR of the front stand are used for the state quantity (u).

The difference mechanism 26 and the integration mechanism 21 constitute a control amount feedback control system. That is, the output side plate thickness h and the tension τ detected by using the detection device 3 or the observation device 7.
The difference between the two control amounts and the setup value indicating the target of each control amount given by the setup control system 4 is obtained by the difference mechanism 26, and the integration value is multiplied by the integration gain by the integration mechanism 21 to integrate the control amount. Generate a command component. The control amount (y) of the present embodiment includes the rear tension τb
And the estimated thickness h _MF of the exit side just below the roll by the observation device 7
And the delivery side plate thickness h.

The command generating mechanism 24 adds the state deviation command component from the proportional mechanism 20, the control amount command component from the integrating mechanism 21 and the target command value given by the setup control system 4, and outputs the result to the actuator 8. Generate a command (manipulated variable).

The operating ends of the actuator 8 include a pressing device 13 for changing the pressing position and a roll driving device 16 for changing the speed. The above operation commands are generated and output for each of the pressing position component and the speed component. You.

According to the configuration of the present embodiment, the state feedback control system is controlled so that the error of the measured value of the state quantity with respect to the operating point becomes zero. State tension τ
Since the rear tension τb, which has a greater influence on the plate thickness than f, is employed, a highly responsive state quantity control that improves the plate thickness accuracy is realized.

Further, the control amount feedback control system maintains the product thickness at a desired accuracy by controlling the delivery side thickness, and prevents a sudden change by controlling the tension, thereby realizing stable operation.

Next, the DDC controller 5 shown in FIG.
Will be described with respect to a control model (control parameter) when designing an optimal servo system.

The DDC controller 5 is provided with a target value of the control amount and an operating point of the state amount as a setup value from the setup control system 4. In this case, the DDC controller 5 is a so-called regulator system that operates to make the deviation between the operating point and the actual value zero. Therefore, the equation of state is described by a deviation value system for obtaining a deviation from the setup value.

The rolling phenomenon is expressed by a gauge value equation of a deviation value system shown in (Equation 4) and a rolling load equation of a minute change which is tailored and developed near the operating point shown in (Equation 5).

[0037]

(Equation 4)

[0038]

(Equation 5)

When (Equation 4) and (Equation 5) are arranged and put together, (Equation 6) is derived.

[0040]

(Equation 6)

Next, the operations of the pressing-down device 13 and the roll driving device 16 which are the operation ends of the actuator are described as follows.
Approximation by the next delay gives (Equation 7) and (Equation 8).

[0042]

(Equation 7)

[0043]

(Equation 8)

The rear tension τb of the rolling mill is represented by (Equation 9), and when a minute change thereof is obtained from the constant mass flow equation, it becomes (Equation 10).

[0045]

(Equation 9)

[0046]

(Equation 10)

The exit side sheet speed Vo and its minute change equation are expressed by (Equation 1).
A small change equation of the input side plate speed Ve in which (Equation 11) is substituted into (1) is shown in (Equation 12).

[0048]

[Equation 11]

[0049]

(Equation 12)

(Equation 11) and (Equation 12) are substituted into (Equation 9) to derive (Equation 13).

[0051]

(Equation 13)

A small change equation obtained by tailoring the advanced rate equation is shown in (Equation 14).

[0053]

[Equation 14]

By substituting equation (14) for equation (13), equation (15) is obtained.

[0055]

(Equation 15)

Here, from the relationship between the front tension τf and the back tension τb shown in (Formula 16), (Formula 15) is integrated with the back tension to obtain (Formula 17).

[0057]

(Equation 16)

[0058]

[Equation 17]

By substituting (Equation 11) for (Equation 17), (Equation 18) is obtained.

[0060]

(Equation 18)

As described above, when the relational expressions of the state amount, ie, the rolling position S, the roll speed VR, and the back tension τb are collectively displayed as a matrix, the state equation (Equation 19) is obtained.

[0062]

[Equation 19]

As a result, the roll drive unit 16 of the front stand (i-1) is selected as the operation end of the DDC controller 4 in this embodiment, together with the pressure control unit 13 of the own stand (i).

Next, the matrices A, B, and C of each term in (Equation 19)
And the vectors of the state quantity x, the operation quantity u, and the control quantity y are symbolically represented as in (Equation 20), and are discretized in the control cycle T _S to obtain the state equation of (Equation 21).

By calculating the matrix elements shown in Table 1 for each state of the operating point for this state equation (Equation 23), linear approximation around the operating point becomes possible.

[0066]

(Equation 20)

[0067]

(Equation 21)

[0068]

[Table 1]

When the state equation of (Equation 21) is obtained, FIG.
The control parameters Fx, Fe of the state feedback control system and the control amount feedback control system are given as (Equation 22). The calculation of the control parameters is obtained by solving the Riccati equation based on the state equation,
"Automatic Control Handbook Part 1 (15
4)).

[0070]

(Equation 22)

Next, the detailed configuration and operation of the DDC controller 5 designed with the optimal servo control system will be described with reference to FIGS.

FIG. 8 shows the relationship between signals and computation in the servo system, and is an explanatory diagram in which relational expressions of control parameters, state quantities, control quantities, or operation quantities are applied to the configuration of FIG. From the state feedback system, a roll-down position component △ Sx and a roll speed component △ VRx of the state deviation command △ Ux are output. From the control amount feedback system, a roll-down position component Se and a roll speed component VRe of the control amount command Ue are output.
Further, from the setup control system 4, the operation command target value U
The rolling position component Ss and the roll speed component VRs of s are output. These are added by the command generation mechanism 24 for each component, and an operation command U (= Sp, VRp) is output.

FIG. 9 shows details of the state feedback control system. According to (Equation 23), the differential mechanism 25 calculates the i-stand pressure reduction position S detected by the detection device 3 at a predetermined cycle.
i, roll speed VRi-1 of front stand and rear tension τ
bi and operating points Ssi, VR from the setup control system
By taking the difference from si-1, τbsi, the deviation Δ
Si, ΔVRi−1, and Δτbi are output.

[0074]

(Equation 23)

The proportional control mechanism 20 calculates the deviation value Δ
Si, ΔVRi-1, Δτbi, the proportional gain fx ₁₁ ,
fx ₁₂ and fx ₁₃ are multiplied and added to obtain a position deviation command component △ Sxi of the i-stand pressure reduction device. Similarly,
The respective deviation values are multiplied by the proportional gains fx ₂₁ , fx ₂₂ , and fx ₂₃ , respectively, and added to obtain a speed deviation command component △ VRxi-1 of the roll drive device of the preceding (i-1) stand.

FIG. 10 shows the details of the control amount feedback control system. According to (Equation 24), the differential mechanism 26 calculates the rear tension τbi by the tension meter and the sheet thickness h by the outlet thickness gauge.
xi is input and the difference between the sheet thickness hMFi immediately under the roll estimated by the observation device 7 and the target sheet thickness hsi and the rearward tension target value τbsi given by the setup control system 4 is calculated. Output Δτbi. The thickness hMF immediately below the roll will be described later.

[0077]

(Equation 24)

The integrating mechanism 21 calculates a deviation value Δh,
iΔτbi is multiplied by the integral gains fe ₁₁ and fe ₁₂ , summed up, integrated, and the position command component S of the i-stand pressure reduction device
Find ei. Similarly, the integral gain fe ₂₁ ,
integrated After summing multiplied by fe _22, obtains a speed command component VRei of i-1 stand roll driving device.

FIG. 11 shows details of the command generation mechanism 24.
The command generating mechanism 24 includes a target value Ssi for a reduction command of the setup control system 4, a reduction command ΔSxi from the proportional mechanism 20,
The reduction command Spi, which is the sum of the reduction command Sei from the integrating mechanism 21 and is output to the reduction position control device 13 of the i-stand.
Generate Similarly, the sum of the speed command VRsi-1 of the setup control system 4, the speed command ΔVRxi-1 of the proportional mechanism 20, and the speed command VRei-1 of the integrating mechanism 21 is output to the roll drive device 16 of the i-1 stand. A speed command VRpi-1 is generated.

FIG. 12 shows the configuration of an observation device for estimating the plate thickness hMF immediately below the roll. The mass flow thickness estimating device 70, which is an embodiment of the observation device 7, has an inlet thickness H, which is a measurement value of the thickness gauge 31 located upstream of the i-stand of the tandem rolling mill.
i and the input-side plate speed vei, which is a measurement value of the plate speedometer 32, and i
The output side sheet speed voi, which is a measurement value of the sheet speed meter 34 located downstream of the stand, is input to the arithmetic unit 71, and the calculation of (Equation 25) is performed to obtain the output side sheet thickness hMFi immediately below the roll of the i-stand.

[0081]

(Equation 25)

The thickness hMF immediately below the roll is calculated (Equation 2).
5) includes an offset that cannot be directly detected. Therefore, the thickness hMF immediately below the roll can be estimated by obtaining the offset amount e as described below.

As shown in FIG. 13, there is a dead time Td between the time when the delivery side plate thickness is actually changed just below the roll (b) and the time when the thickness is measured by the thickness gauge 33 (c). This wasted time is a value obtained by dividing the distance L between immediately below the roll and the exit side thickness gauge 33 by the exit side sheet speed voi. Note that the change in the exit side plate thickness includes a rolling effect by the gap and the tension and a change by the offset. Although the offset e changes stepwise in FIG. 5A for explanation, it actually changes gradually due to roll temperature, roll wear, and the like.

First, the output hMFi (the offset is initially set to 0) of the arithmetic unit 71 is delayed via a dead time unit 72 composed of, for example, a shift register or the like.
A tracking plate thickness which is in phase with the output of No. 3 is obtained (d). When the difference ε between the tracking plate thickness and the output of the plate thickness gauge 33 is obtained by the adder 73 and the noise is removed through the filter 74, the offset e is obtained.

When the offset e is fed back to the arithmetic unit 71 (f), the calculation of the thickness hMFi becomes possible. As shown in FIG. 9E, a dead time Td is generated from the occurrence of the offset to the removal of the offset, and the offset e during this time becomes an error (g), but the actual offset changes slowly, so that the previous offset is changed. The change from e is very small and can be ignored.

The sheet thickness h just under the roll obtained in this way is
MFi can be given to the difference mechanism 26 as a delivery side plate thickness hi without delay. By the way, the dead time Td is about 50
When the control cycle is 0 ms and the control cycle is 20 ms, the sheet thickness immediately below the current roll is fed back to the 25th control command in the output side thickness gauge, but in this embodiment, the influence of the offset is eliminated in real time. As a result, the response to the sheet thickness on the delivery side can be remarkably improved, and the product quality can be improved.

As described above, the rolling control apparatus according to the present embodiment uses the rolling position, the rear tension having a large control effect, and the front stand roll speed for the rear tension control as the state variables, and the dead time as the control variable. Optimal servo control system that outputs operation commands to the roll-down device of its own stand and the roll drive device of its front stand (or its own stand) using the plate thickness and back tension directly under the roll, and the plate directly under the roll without wasted time By combining a mass flow thickness estimating device for obtaining the thickness, highly accurate thickness control is realized. Incidentally, in this embodiment, the base material plate thickness is 2.3 mm and the product plate thickness is 0.3 mm.
Applied to a rolling schedule of 233 mm, the product thickness accuracy (thickness deviation of the product thickness) was 0.64 by the conventional AGC.
% To 0.32%, which is almost twice as high.

[0088]

According to the present invention, the plate thickness immediately below the roll can be estimated with high accuracy including the offset amount. Furthermore, since the estimated plate thickness immediately below the roll with no wasted time is used for the output side plate thickness of the control amount, real-time response to disturbance or the like becomes possible, and desired plate thickness accuracy can be maintained and product quality can be improved. .

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a rolling control device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a rolling system to which the present invention is applied.

FIG. 3 is a schematic diagram illustrating a mechanical configuration of a rolling mill.

FIG. 4 is a schematic diagram illustrating the operation of a rolling mill.

FIG. 5 is an explanatory diagram of operating points of a rolling mill.

FIG. 6 is an explanatory diagram of an operating point when a base material changes.

FIG. 7 is an explanatory diagram of a rolling phenomenon for removing disturbance by DDC control.

FIG. 8 is an explanatory diagram of a relationship between control parameters and input / output signals in the configuration of FIG. 1;

FIG. 9 is an explanatory diagram of a state feedback control system.

FIG. 10 is an explanatory diagram of a control amount feedback control system.

FIG. 11 is an explanatory diagram of a command generation mechanism.

FIG. 12 is a configuration diagram of a mass flow plate thickness estimation device.

FIG. 13 is an explanatory diagram of an offset.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 rolling mill 2 rolling control device 3 detecting device 4 setup control system 5 DDC controller 6 rolling mill model 7 observation device 8 actuator 10
Work roll, 13 ... Hydraulic pressure reduction device, 14 ... Rolled material, 1
6 roll drive device, 20 proportional mechanism, 21 integral mechanism, 24 command generation mechanism, 25, 26 difference mechanism, 70
... Mass flow thickness estimation device.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Takashige 5-2-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside Hitachi Information & Control Systems Co., Ltd. (72) Inventor Kenichi Yoshioka 5-chome, Omika-cho, Hitachi City, Ibaraki Prefecture 2-1 Hitachi Information Control System Co., Ltd. (72) Inventor Yuki Katayama 5-2-1 Omikacho, Hitachi City, Ibaraki Prefecture Hitachi Information Control System Co., Ltd. (72) Inventor Yutaka Saito Omika, Hitachi City, Ibaraki Prefecture 5-2-1, Machi-cho, Hitachi, Ltd. Omika Plant (72) Inventor Tetsu Hattori 5-2-1, Omika-cho, Hitachi, Ibaraki Prefecture, Ltd. Omika Plant, Hitachi, Ltd. (72) Inventor Takashi Okada Hitachi, Ibaraki Prefecture 7-1-1, Omikamachi, Hitachi City Hitachi, Ltd. Hitachi Research Laboratory (72) Inventor Kenji Nakatani Omikamachi, Hitachi City, Ibaraki Prefecture No. 2-1 Hitachi, Ltd. Omika Plant (72) Inventor Jin Chor Jae Korea No. 1 Goesong-dong, Pohang, Gyeongbuk Republic Inside Pohang Sogo Steel Co., Ltd. (72) Inventor Lee Sang-gil Korea 1 Goesong-dong Inside Pohang Sogo Steel Co., Ltd. (56) References JP-A-6-142739 (JP, A) JP-A-3-138002 (JP, A) JP-B-51-41989 (JP, B2) (58) Field surveyed (Int.Cl. ⁷ , DB name) B21B 37/16-37/20 B21B 37/52 B21B 38/04

Claims (5)

(57) [Claims] 1. A method for estimating an exit side plate thickness of a rolling mill comprising a plurality of stands with i = 1 to n at a sampling period, comprising: an entrance side plate thickness Hi and an entrance side plate speed vei from an entrance side of an i stand.
Is measured from the exit side of the i-stand, the exit-side sheet speed voi is measured, and the exit-side sheet thickness immediately below the roll of the i-stand is estimated from the measured values according to the constant law of mass flow. roll but the time to reach the outlet side of the plate thickness meter i stand, obtains the offset amount obtained by subtracting the measured value by the roll just below exit side thickness and the exit side of the plate thickness meter, the offset amount for the next cycle Estimated value of the sheet thickness just below the delivery side
A method for estimating the exit-side sheet thickness of a rolling mill, characterized by adding 2. The rolling mill according to claim 1 , wherein the offset amount is obtained by subtracting a value measured by a thickness gauge immediately below the roll and a thickness value measured by the thickness gauge on the exit side and performing a filtering process. How to estimate the outlet plate thickness
Law . 3. An actual value of a plurality of state quantities and control quantities is detected in a predetermined cycle for each stand of the rolling mill, and an error between the actual value and an operating point or a target set value set by a setup controller is determined. In a rolling mill control method of performing multi-variable control so as to eliminate, a feedback control is performed so as to eliminate an error from each set value (operating point) using a rolling position, a rear tension and a roll speed of a front stand as a state quantity, and an input side plate. From the measured values of the thickness, the entrance side sheet speed and the exit side sheet velocity, the exit side sheet thickness directly under the roll is estimated according to the law of constant mass flow, and the exit side sheet thickness immediately below the roll and the measured rear tension are used as control amounts to set values (target values). A method for controlling a rolling mill, wherein feedback control is performed so as to eliminate an error from (1). 4. A detecting device for detecting actual values of a plurality of state quantities and a plurality of control amounts of a rolling mill including a plurality of stands at predetermined intervals, and an operating point and a target set value determined by a setup controller. A rolling mill control device including a DDC control device that controls the error of the actual value to be eliminated, wherein the DDC control device performs a feedback control as a state quantity using a rolling position, a rear tension, and a roll speed of a front stand as a state amount. And, a control amount feedback control means for performing feedback control of the output side plate thickness and the rear tension as a control amount, and estimating the output side plate thickness immediately below the roll according to a constant mass flow rule from the measured values of the input side plate thickness, the input side plate speed and the output side plate speed, An apparatus for controlling a rolling mill, comprising: an observation device that sets a thickness of a delivery sheet immediately below a roll to the delivery sheet thickness. 5. The observing device according to claim 4 , wherein the observing device calculates an outlet plate thickness immediately below the roll according to a constant law of mass flow, and measures the outlet plate thickness immediately after the outlet plate thickness actually changes immediately below the roll. After a time corresponding to the dead time until the sheet is discharged, an offset detection unit is provided which compares the delivery thickness under the roll with the delivery thickness gauge, filters this difference value and feeds back the difference to the arithmetic means. A rolling mill control device, characterized in that: