JP3085502B2 - Rolling mill control device and method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-variable control rolling mill control device comprising an optimum servo system and a control method thereof.

[0002]

2. Description of the Related Art As a conventional example of rolling mill control using an optimum servo system, Compute Roll No. 27 (1989)
Year) rolling control. This example is a control model of bar rolling by a tandem rolling mill, and a control model of multivariable control using a rolling amount, a forward tension, a roll rotation speed as a state quantity, and a sheet thickness, a sheet width, a rolling load, and a torque as a control amount. Is composed.

[0003] Here, from the idea that rolling is performed by elongating the base material by the rolling load and the tension, the rotation speed of the self-standing roll for controlling the forward tension is used as the state quantity. The thickness measured as the control amount is directly used as measured by a thickness gauge.

[0004]

In the above example, the forward tension is used as the state quantity of the optimum servo system. But,
When comparing the degree of influence of the front tension and the rear tension on the plate thickness, there is a problem that the degree of influence of the front tension is smaller and the control effect is smaller.

On the other hand, the control variable uses a dependent variable such as a rolling load, and there is no consideration for unstable control due to a sudden change in tension.

Further, the sheet thickness measured by the exit side sheet thickness gauge has a large dead time (about 500 ms) while the rolled material moves from immediately below the roll to the sheet thickness gauge. 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 high-precision and stable rolling control apparatus and method by selecting the state quantity and control quantity of the multivariable control effectively and to a minimum, and using an optimum servo configuration.

[0008]

SUMMARY OF THE INVENTION The object of the present invention is to provide a detecting device for detecting a plurality of state variables and a plurality of actual control values of a plurality of control variables of a rolling mill having a plurality of stands at predetermined intervals, and an operation determined by a setup control device. In a rolling mill control device including a DDC control device for controlling an error between a set value of a point or a target and the actual value, the DDC control device performs feedback control using a rolling position, a rear tension, and a roll speed as state quantities. This is achieved by configuring as an optimal servo system having state feedback control means and control amount feedback control means for performing feedback control using the delivery side plate thickness and the rear tension as control amounts.

Further, the output side plate thickness of the controlled variable is achieved by using the plate thickness immediately below the roll estimated by the observation device based on the law of constant mass flow.

[0010]

According to the present invention, as a state variable in multivariable control, an independent variable having a large influence on the rolling process is adopted, and the rolling process is controlled by the state feedback control system with high response. The constant control of the plate thickness is performed.

In particular, the sheet thickness accuracy can be improved by setting the rear tension, which has a greater control effect than the conventional front tension, and the roll speed of the front stand for controlling the rear tension together with the rolling position as a state quantity. Further, by using the tension as the control amount, it is possible to suppress a sudden change in the tension and realize a stable operation without plate breakage.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram showing a rolling control system to which the present invention is 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.

A rolling mill has a strong nonlinearity and cannot apply a modern control theory based on a 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 is set by the set-up control system 4 to an operating point or a set-up value which is a target value of a control amount or an operation amount, and makes the deviation between the set-up value and the actual value from the detecting device 3 zero. Works like that.

The observation device 7 uses the 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 directly under the roll, which cannot be measured directly,
Estimate hMF. Plate on i-stand entry side of tandem rolling mill
Incoming sheet thickness Hi by thickness gauge and incoming sheet speed ve by sheet speed meter
i and the exit side plate speed voi by the plate speed meter on the exit side of the i stand.
Measure and calculate the constant law of mass flow based on these measured values
And the outlet plate thickness hMFi just below the i-stand roll.
Is estimated.

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 work roll 10 and the rolled material 14.
Shows the relationship. 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. Among these quantities, the Hill's approximate expression shown in (Equation 1) expresses the physical relationship of the rolling load. This approximate expression is an expression obtained by an experiment.

[0019]

(Equation 1)

[0020]

(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).

[0023]

(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 h.
1, the rolling load changes from P0 to P1. as a result,
The plate thickness deviates from the target value h.

Then, as shown in FIG. 7, the rolling position S of the rolling mill is moved, and the thickness control for achieving the desired thickness is performed. 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 a rolling mill control device according to an embodiment of the present invention, which is 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 difference between the control amount detected by using the detection device 3 or the observation device 7 and the setup value indicating the target of the control amount given by the setup control system 4 is obtained by the difference mechanism 26, and the difference value is calculated by the integration mechanism 21. Is multiplied by an integral gain to generate a control amount command component. The control amount (y) of this embodiment includes:
The exit side plate thickness h and the rear tension τb are used.

The command generation mechanism 24 adds the state deviation command component from the proportional mechanism 20, the control amount command component from the integration 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 end of the actuator 8 includes 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. As shown in Table 1, the back tension τb, which has a greater influence on the plate thickness than the conventional front tension τf, is adopted as the state quantity, realizing a highly responsive state quantity control that improves the thickness accuracy. I do.

[0035]

[Table 1]

Further, the control amount feedback control system maintains the product thickness at a desired accuracy by controlling the delivery thickness, and prevents a sudden change by controlling the tension to realize 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 gage meter equation of a deviation value system shown in (Equation 4) and a rolling load equation of a minute change which is tailored near the operating point shown in (Equation 5).

[0040]

(Equation 4)

[0041]

(Equation 5)

(Equation 6) is derived by organizing (Equation 4) and (Equation 5).

[0043]

(Equation 6)

Next, the operations of the pressing 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).

[0045]

(Equation 7)

[0046]

(Equation 8)

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

[0048]

(Equation 9)

[0049]

(Equation 10)

The exit side sheet speed Vo and its minute change equation are given 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).

[0051]

[Equation 11]

[0052]

(Equation 12)

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

[0054]

(Equation 13)

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

[0056]

[Equation 14]

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

[0058]

(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).

[0060]

(Equation 16)

[0061]

[Equation 17]

When (Equation 11) is substituted for (Equation 17), (Equation 18) is obtained.

[0063]

(Equation 18)

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

[0065]

[Equation 19]

In (Equation 19), the roll speed VR _i-1 of the front stand is used at the operation end for the following reason. FIG. 8 is a schematic diagram for explaining the progressive control of the rolling mill. When the roll speed of the rolling mill is changed, the roll speed on the upstream side of the rolling stand to be changed is changed so that the mass flow is constant. For example, if the roll speed of the i-stand is changed from V0 to V1, i-1 stand, i
-2 stand,. . . . The roll speed of (Equation 20),
It is obtained and changed as shown in (Equation 21).

[0067]

(Equation 20)

[0068]

(Equation 21)

From the above equation, it can be seen that when changing the rear tension of the i-stand, changing the roll speed of the i-1 stand requires less than one stand. Thus, as the operation end of the DDC controller 4 in the present embodiment, the roll drive device 16 of the front stand (i-1) is selected together with the pressure reduction control device 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 22), and are discretized in the control cycle T _S to obtain the state equation of (Equation 23).

By obtaining the matrix elements shown in Table 2 for each state of the operating point for this state equation (Equation 23), linear approximation around the operating point becomes possible.

[0072]

(Equation 22)

[0073]

(Equation 23)

[0074]

[Table 2]

When the state equation of (Equation 23) is obtained, FIG.
The control parameters Fx and Fe of the state feedback control system and the control amount feedback control system are given as (Equation 24). 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)).

[0076]

(Equation 24)

[0077] Next with reference to FIGS. 9 to 12, a detailed configuration and operation of the DDC controller 5 which is designed in an optimal servo control system.

FIG. 9 shows the relationship between signals and calculations 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. 10 shows details of the state feedback control system. In accordance with (Equation 25), the differential mechanism 25 determines the rolling-down position Si of the i-stand, the roll speed VRi-1 and the rear tension τbi of the front stand detected by the detection device 3 at a predetermined cycle, and the operating point Ssi from the setup control system. , V
The difference between Rsi−1 and τbsi is calculated, and deviation values ΔSi, ΔVRi−1, and Δτbi of the state quantities are output.

[0080]

(Equation 25)

The proportional control mechanism 20 calculates the deviation 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. 11 shows the details of the control amount feedback control system. According to (Equation 26), 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. Above
As described above, the output side plate thickness of the control amount in this embodiment is
The row estimated by the measuring device 7 based on the constant law of mass flow
The plate thickness hMFi immediately below is used. And the observation device 7
Entry side plate thickness Hi at entry side of i-stand of Ndem rolling mill, entry side plate
Measures the speed vei and the exit side plate speed voi on the exit side of the i-stand.
Based on these measured values, the calculation of the constant law of mass flow is performed.
To estimate the thickness hMFi immediately below the roll of the i-stand. This
The thickness hMFi directly under the roll of
Equivalent is the literature "Theory and practice of sheet rolling (Nippon Steel
Association, edition date; September 1984, Chapter 2, pages 6-9
Page) "and the like.

[0083]

(Equation 26)

The integrating mechanism 21 calculates the deviation value Δh of each control amount.
i, Δτbi are multiplied by integral gains fe ₁₁ , fe ₁₂ to obtain a sum and then integrated to obtain a position command component Sei of the i-stand pressure reducing device. Similarly, the integral gain f
The sum is multiplied by e ₂₁ and fe ₂₂ , then integrated, and the speed command component VRei of the i-1 stand roll driving device is obtained.

FIG. 12 shows the 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.

[0086]

[0087]

[0088]

[0089]

[0090]

[0091]

[0092]

FIG . 13 shows a control operation by the rolling control device of this embodiment. When a disturbance occurs in the base material as shown in FIG. 7A, the forward tension τf changes as shown in FIG. When the forward tension τf is used as a state quantity as in the related art, a large control command must be output because the influence on the plate thickness is small. However, the amplifier of the actuator saturates for a control command exceeding a certain value, and the control output becomes as shown in FIG. As a result, a large deviation remains in the delivery side plate thickness h as shown in FIG. 3D, and a sufficient control effect cannot be obtained.

On the other hand, since the rear tension τb has a large influence on the sheet thickness, the control effect can be exerted by the control output in the linear region where the saturation does not occur as shown in FIG. In addition, it is possible to improve the thickness accuracy by reducing disturbance components.
By the way, this embodiment is applied to a rolling schedule of a base material sheet thickness of 2.3 mm and a product sheet thickness of 0.233 mm, and the product sheet thickness accuracy (sheet thickness deviation of the product sheet thickness) is set to 0.1 according to the conventional AGC.
The improvement was about twice, from 64% to 0.32%.

As described above, the rolling control device 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. Using the sheet thickness directly under the roll and the back tension, find the optimal servo control system that outputs operation commands to the roll-down device of the self-stand and the roll drive device of the front stand (or the self-stand), and the plate thickness directly under the roll
High-accuracy plate thickness control was realized by combining observation equipment for the measurement .

[0096]

According to the present invention, the rolling control by the optimum servo system using the rolling position, the rear tension and the roll speed of the front stand as the state quantities and the output side plate thickness and the rear tension as the control quantities is realized. In addition, the thickness accuracy can be dramatically 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 in which disturbance is removed by DDC control.

FIG. 8 is an explanatory diagram of successful control.

FIG. 9 is an explanatory diagram of a relationship between control parameters and input / output signals in the configuration of FIG. 1;

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

FIG. 11 is an explanatory diagram of a control amount feedback control system.

FIG. 12 is an explanatory diagram of a command generation mechanism.

FIG. 13 is a view showing the effectiveness of the rolling control operation of the present embodiment .
FIG.

[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 ... Roll-down device, 14 ... Rolled material, 16 ...
Roll drive device, 20: proportional mechanism, 21: integrating mechanism, 2
4. Command generation mechanism, 25, 26 Difference mechanism.

──────────────────────────────────────────────────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 City, Ibaraki Pref. Omika Plant, Hitachi, Ltd. (72) Inventor Takashi Okada Hitachi, Ibaraki 7-1-1, Omika-cho, Hitachi City Hitachi Research Laboratory, Ltd. (72) Inventor Kenji Nakatani Omika-cho, Hitachi City, Ibaraki Prefecture No. 2-1 Hitachi Omika Plant Co., Ltd. (72) Inventor Jin Chor-Jae Korea No. 1 Goesong-dong, Pohang, Gyeongbuk, Republic of Korea Inside Pohang Sogo Steel Co., Ltd. (72) Inventor Lee Sang-gil, Korea No. 1 Goesong-dong Inside Pohang Sogo Steel Co., Ltd. (56) References JP-A-7-16625 (JP, A) JP-A-5-31517 (JP, A) JP-A-3-138002 (JP, A) JP-A-6-142739 (JP, A) JP-B-2-32041 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B21B 37/16-37/20 B21B 37/52

Claims (12)

(57) [Claims] An actual value of a plurality of state variables and a controlled variable of a rolling mill including a plurality of stands is detected at predetermined intervals, and the actual value is compared with set values of an operating point, a target, and the like set by a setup controller. In a rolling mill control method that performs multivariable control so that errors are eliminated, feedback control is performed so as to eliminate errors between actual values and set values (operating points) using a rolling position, a back tension, and a roll speed as state quantities, and an output side.
A rolling mill control method, wherein feedback control is performed so as to eliminate an error between an actual value of the control amount including a sheet thickness and a set value (target value). 2. The method according to claim 1, wherein a state value of the rolling mill including a plurality of stands and actual values of a plurality of control amounts are detected in a predetermined cycle, and the actual value is compared with set values such as an operating point and a target set by a setup controller. In a rolling mill control method that performs multivariable control so as to eliminate errors, feedback control is performed so as to eliminate errors between the actual value of the state quantity and the set value (operating point), and each of the output side plate thickness and the rear tension is set as a control amount. A rolling mill control method characterized by performing feedback control so as to eliminate an error between an actual value and a set value (target value). 3. An actual value of a plurality of state quantities and a plurality of control quantities of a rolling mill comprising a plurality of stands is detected at predetermined intervals, and the actual value is compared with an operating point and a target set value set by a setup controller. In a rolling mill control method that performs multivariable control so as to eliminate the error, feedback control is performed so as to eliminate the error between the actual value and the set value (operating point) using the rolling position, the rear tension, and the roll speed of the front stand as state quantities. In addition, a rolling mill control method characterized in that feedback control is performed so as to eliminate an error between each actual value and a set value (target value) using the delivery side plate thickness and the rear tension as control amounts. 4. The state amount feedback control according to claim 3, wherein the state amount feedback control obtains deviations between each of the state amounts and the corresponding set value (operating point), and multiplies these deviations by a proportional gain. A first operation command value corresponding to the deviation is generated. In the feedback control of the control amount, a deviation between each of the control amounts and the corresponding set value (target value) is obtained, and these deviations are multiplied by an integral gain. To generate a second operation command value corresponding to the control amount deviation, and to generate a third operation command value based on the sum of the first operation command value and the second operation command value. A method for controlling a rolling mill, wherein an output is provided to an actuator. 5. The system according to claim 4, wherein each of the first, second and third operation command values comprises a rolling position command value for changing a roll gap and a speed command value for changing a roll speed. A rolling mill control method, which is required for each rolling mill. 6. The rolling mill control method according to claim 5, wherein the rolling position command value is output to a rolling device, and the speed command value is output to a roll driving device. 7. The roll driving device according to claim 6,
A method for controlling a rolling mill, comprising a roll drive device for a front stand. 8. A detecting device for detecting actual values of a plurality of state quantities and a plurality of control amounts of a rolling mill having a plurality of stands at predetermined intervals, an operating point and a target set value determined by a setup control device, and A rolling mill control device provided with a DDC control device for controlling so as to eliminate an error in the actual value, wherein the DDC control device is a state feedback control means for performing feedback control as a state amount using a rolling position, a rear tension, and a roll speed of a front stand; And a rolling mill control device comprising an optimum servo system having a control amount feedback control means for performing feedback control of the exit side plate thickness and the rear tension as control amounts. 9. The state feedback control means according to claim 8, wherein the state feedback control means calculates a deviation between each of the state variables and the corresponding set value, and multiplies the deviation by a proportional gain to calculate the state variable deviation. A proportional mechanism that generates a corresponding operation command value, the control amount feedback control means includes a difference mechanism that calculates a deviation between each of the control amounts and the corresponding set value;
An operation command that outputs an operation command value to the actuator based on the operation command values of the proportional mechanism and the integration mechanism by integrating the deviation with an integral gain to generate an operation command value corresponding to the control amount deviation; A rolling mill control device comprising command generation means for determining a value. 10. The system according to claim 9, wherein the proportional mechanism and the integrating mechanism generate an operation command including a rolling command component for changing a rolling position and a speed command component for changing a roll speed.
The command generating means generates a rolling position operation command value and a speed operation command value by adding for each component, and outputs the rolling position operation command value to a rolling device and the speed command value to a roll drive device of a front stand. A rolling mill control device characterized by being configured as described above. 11. The sheet thickness immediately below a roll of the stand according to claim 8, 9 or 10, based on the sheet thickness on the entry side and the sheet speed and the sheet speed on the exit side of the stand from the detection device. A rolling mill control device comprising an observation device for inputting a plate thickness immediately below a roll as the outlet plate thickness to a difference mechanism of the control amount feedback control means. 12. A detecting device for detecting actual values of state quantities and control amounts of a tandem rolling mill comprising a plurality of stands at predetermined intervals, and a setup having a rolling model and determining an operating point according to a non-linear rolling state. A control device and a DDC control device that outputs an operation command to a rolling device and a roll driving device of a rolling mill of each stand so as to eliminate a deviation between a set value of an operating point or a target to be set up and the actual value. In the rolling mill control device provided, the DDC control device uses a rolling position, a rear tension and a roll speed of the front stand as the state quantity, and a rolling position set value, a rear tension setting value and a front tension setting value corresponding to these state quantities. A deviation from the roll speed set value is obtained, and the deviation is multiplied by a first proportional gain and a second proportional gain, respectively, to obtain a rolling position command component and a speed corresponding to the state variable deviation. State quantity feedback control means for generating a degree command component, and using the outlet sheet thickness and the rear tension as the control amounts, calculating deviations between the outlet sheet thickness set value and the rear tension set value corresponding to these control amounts, and calculating these deviations. Control amount feedback control means for multiplying each by a first integral gain and a second integral gain to generate a rolling-down position command component and a speed command component corresponding to a control amount deviation, the state quantity feedback control means and the control A rolling position operation command and a speed operation command are generated by adding the rolling position command component and the speed command component from the amount feedback control means and the rolling position target value and the speed target value from the setup control device for each component. Command generating means for outputting the latter to the roll drive device of the front stand in the press-down device of the stand; The machine control unit.