JP3071300B2 - Looper height control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a looper height control device for controlling the height of a looper disposed between stands of a tandem rolling mill.

[0002]

2. Description of the Related Art Sheet thickness and sheet width are part of evaluation criteria for final products obtained by hot rolling or cold rolling. Among them, the automatic thickness control is performed on the thickness, and the automatic width control is performed on the width. On the other hand, since the tension applied to the material during rolling affects the thickness and width of the sheet, control for maintaining the tension at a certain value is also performed.

[0003] In particular, since the material to be rolled in hot rolling is heated to a high temperature by heat treatment and has a low deformation resistance, a large tension tends to cause breakage. If no tension is applied to prevent this breakage, a large loop may occur between the rolling stands when the condition continues, which may cause an accident.

In order to obtain the tension and an appropriate loop between the stands of the material to be rolled, the hot rolling mill is particularly provided with a looper, and a desired operation is performed by the looper. The operation method for obtaining the tension and the loop includes a rotation speed control of a looper drive motor and a rotation speed control of a motor for driving a rolling mill, that is, a rotation speed of a main motor. These controls include:
A control device based on PID calculation is widely used.

[0005]

The tension of the rolled material, the height of the looper, the rotation speed of the looper drive motor and the drive speed of the main motor are closely related to each other. It is difficult to keep the constant, and the looper height is vibrating, so that it may be difficult to obtain a constant tension and a loop of the rolled material between stands. In particular, when the tension is controlled by the gap between the rolls, a large error occurs in the tracking of the material to be rolled, and the desired control cannot be performed. Will be.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to constantly control the height of a looper disposed between the stands of a tandem rolling mill even when the rolling conditions fluctuate. It is an object to obtain a looper height control device that makes it possible.

[0007]

According to the present invention, there is provided a looper motor speed control means for controlling the speed of a looper drive motor in accordance with a rotation speed command value, and the height of a looper disposed between stands of a tandem rolling mill is determined . The integral value of the rotation speed command value is
In a looper height control device that controls based on the relationship that results in a looper height, a looper height command value, a variable representing a model of a looper control system including a looper motor speed control means, a response of the looper height control system And a setting means for setting a variable for designating a cutoff frequency of the cut-off frequency and a variable for adjusting the response of the looper height control, and substituting the variable set by this setting means into a predetermined calculation formula. Control gain calculating means for obtaining the control gain as a numerical value; and a control gain calculated by the control gain calculating means, a looper height command value set by the setting means, and a looper height detection value based on the looper height detection value. Control operation means for calculating a rotation speed command value of the looper drive motor for causing the height to follow the looper height command value and adding the rotation speed command value to the looper motor speed control means.

[0008]

The variables representing the model of the looper control system including the looper motor speed control means, the variables for specifying the response of the looper height, and the variables for adjusting the looper height are converted into predetermined formulas. The control gain is obtained as a numerical value by substituting, and the rotational speed command value of the looper drive motor is calculated using the control gain. Thereby, even if the operation state of the rolled material changes, stable looper height control can be always performed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings.

FIG. 1 is a block diagram showing the configuration of one embodiment of the present invention. In the figure, a rolled material 1 includes an i-th stand 2 (hereinafter, simply referred to as an i-th stand) and an i-th stand
The rolling is performed in the order of the stand 3 (hereinafter, simply referred to as the (i + 1) th stand). Here, assuming that the total number of stands of the tandem rolling mill is n, n = 5 to 7 is general. A device such as a looper to be described below is installed between each stand.
Considering the state between the (i + 1) -th stands, it can be easily extended to other stands. Note that i is in the range of 1 ≦ i ≦ n−1.

When the looper 4 is provided between the i-th stand and the (i + 1) -th stand, the looper height, which is converted into the angle of the looper arm, is detected by the looper height detecting device 5. Looper drive electrokinetic motive driving the looper 4 (hereinafter, referred to as the looper motor) 6 speed detecting apparatus 7 is attached to the looper so as to reduce the deviation of the detected value of the looper motor rotation speed and its command value The speed of the looper motor 6 is controlled by the motor speed controller 8.

The above-mentioned speed command value of the looper motor 6 is calculated by the control calculation means 9. In this case, the looper height command value and the looper motor speed controller 8 are set by the setting means 10.
When the variables that represent the model of the looper control system, including the parameters for specifying the cutoff frequency of the response of the looper height control system , and the variables for adjusting the response of the looper height control are set, respectively, Then, the control gain calculating means 11 substitutes each set variable into a predetermined control gain equation, and obtains the control gain used by the control calculating means 9 as a numerical value. The control calculation means 9 detects these control gains, the looper height command value set by the setting means 10, the looper height command value detected by the looper height detection device 5, and the rotation speed detection device 7. The speed command value of the looper motor 6 is calculated using the detected speed value of the looper motor 6.

Hereinafter, detailed operations of the control calculation means 9 and the control gain calculation means 11 will be described using a model of a looper control system.

FIG. 2 is a block diagram of a control system corresponding to the control system shown in FIG. 1 from which the setting means 10 and the control gain calculation means 11 are omitted. Blocks 12 to 12 in FIG.
17 is the rolled material 1 in FIG. 1, i stand, i + 1 stand,
Looper 4, looper electric motive 6, a looper control system model, including the looper motor speed control device 8. The block 12 corresponds to the looper motor speed controller 8. Block 13 is the looper motor torque constant, Block 14
Is the feedback gain from the looper height to the looper driving torque <br/> block 15 is the transfer function from torque to rotation speed, block 16 is the transfer function from rotation speed of the looper motor to looper height, block 17 is the looper Blocks 14 to 17 correspond to the looper 4.

The blocks 18 to 21 in FIG.
This is a portion corresponding to the control calculation means 9 in the middle. this house,
Block 18 is an integral controller, block 19 is a coefficient of a looper height control system response, block 20 is a feedback gain from rotation speed to motor speed, and block 21 is a feedback gain from looper height to motor speed.

Now, the model of the looper motor speed controller 8 and the looper 4 corresponding to the blocks 12 to 17 is written in the state equation as follows.

[0017]

(Equation 1) Here, Δ added before each symbol indicates a minute change of the symbol, and “•” added above each symbol indicates a time derivative. So, for example, if t represents time,

[0018]

(Equation 2) Becomes

Further, if T represents a turning value and the state vector x = [Δω Δθ Δx _L ] ^T output y = Δθ input u = Δω _ref , the following equation is obtained.

[0020]

(Equation 3) A, B and C in the equation (3) represent the following matrices, respectively.

[0021]

(Equation 4) However, the meanings of the variables in the equation of state are as follows.

G: gear ratio between the looper and the looper motor J: looper motor inertia coefficient θ: looper height (expressed in angle) φ: looper motor torque constant ω: rotation speed of the looper motor f ₁ : looper height off from the looper drive torque
Fed back gain f _2: looper damping factor x _L: looper speed controller internal variables K _L, T _L: control constant of the looper speed controller subscript ref: a command value of the symbol. The above equations (1), (2) and (3) are
Is the equation of state of the system, as is clear from these equations.
The time derivative of the looper height is the rotation speed of the looper motor.
It has become. Therefore, the rotation speed command value of the looper motor
Is added to the looper motor controller to increase the looper height.
Can be controlled.

On the other hand, the control gains of the blocks 18, 20, and 21 corresponding to the control calculation means 9 in FIG. 1 and the adjustment coefficients of the block 19 are calculated and determined by the control gain calculation means 11 and given to the control calculation means 9. . Hereinafter, the calculation of the gain and the determination of the adjustment coefficient in the control gain calculating means 11 will be described.

First, the gain is basically ILQ (Invers
e Linear Quadratic) method. The ILQ method is a solution of the optimal control problem from the viewpoint of the inverse problem. For example, "Generalization of ILQ optimal servo system design method" in the Transactions of the Institute of Systems Control, Takao Fujii, Taku Shimomura, Transactions of the Society of Systems, Control and Information Engineers Vol. 1, No. 6, 1988.

By using the model of the looper control system using the above equations (1) and (2), the control gain K _I of the block 18, the control gain K _{ω of} the block 20, and the control gain K _θ of the block 21 are as follows. It can be expressed by an expression.

[0026] ^{_{K I = 4gJω d 2 / K}} L φT L ... (4) K ω = J / K L φT L ... (5) K θ = 4gJω d / K L φT L ... (6) where, ω _d Is the cut-off frequency of the response of the looper height control system (ra
d / s) and specify the desired value. K _I represents the integral gain of the input signal from the deviation between the looper height command value and the looper height, K _ω represents the feedback gain of the looper motor rotation speed, and K _θ is the looper drive speed from the looper height .
It represents the feed back gain to the torque. (Four)~
As is clear from equation (6), these gains K _I , K _ω ,
_Kθ is expressed by a mathematical expression including a variable expressing a model of a looper control system and a variable of a specified response.

Next, the adjustment coefficient σ of the block 19 is determined so that the looper height control has a desired response. Generally, when the adjustment coefficient σ is set to a large value, a quick response is obtained. However, since the looper motor rotation speed command value, which is the operation amount, also becomes a large value, it cannot be set to a very large value.

In the above equations (4) to (6), T _L , g,
K _L , φ, and J are variables representing a model of the looper control system, ω _d is a variable for designating a cutoff frequency of a response of the looper height control system , and σ is a response of the looper height control. Are set by the setting means 10 as variables.

Thus, the variable T set by the setting means 10
_{Based on L} , g, K _L , φ, J, ω _d , and σ, the control gain calculating means 11 calculates the control gain K _I ,
K _ω and K _θ are calculated and given to the control calculation means 9 as a numerical value together with σ. The control calculation means 9 calculates the gains K _I , K _ω , K _θ , σ, the command value Δθ _ref of the looper height set by the setting means 10, and the speed detection of the looper motor detected by the rotation speed detection device 7. The rotation speed command value Δω _ref is calculated using the value Δω and the detected value Δθ of the looper height detected by the looper height detection device 5 and provided to the looper motor speed control device. Looper motor speed control device of the cook <br/> over path photoelectric motive 6 as the deviation between the speed detection value [Delta] [omega looper motor detected by the rotational speed detector 7 and the rotational speed command value [Delta] [omega _ref becomes zero Control the speed.

In the above embodiment, the case where the motor driven looper is arranged between the stands constituted by the four-roll rolling mills has been described. However, the present invention is applicable to other rolling systems having different rolling mill structures and different looper driving methods. It goes without saying that the present invention is applicable.

[0031]

As is apparent from the above description, according to the present invention, a variable representing a model of a looper control system is set, a control gain is obtained as a numerical value based on the set value, and the control gain is further determined. Is used to calculate the rotation speed command value of the looper motor that causes the looper height to follow the looper height command value, so that stable control of the looper height is always possible even if the rolling conditions fluctuate.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of one embodiment of the present invention, together with a rolling system.

FIG. 2 is a block diagram showing a detailed configuration of one embodiment of the present invention.

[Explanation of symbols]

2 i-th stand 3 (i + 1) -th stand 4 loopers 6 looper drive electrokinetic motive 8 looper motor speed control device 9 control operation unit 10 setting unit 11 controls the gain calculation means

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B21B 39/08 B21B 37/00 B21B 37/50

Claims (1)

(57) [Claims] A looper motor speed control means for controlling the speed of a looper drive motor according to a rotation speed command value, wherein the height of a looper disposed between stands of a tandem rolling mill is determined by:
A looper height control device that controls the integral value of the rotation speed command value based on a relationship of a looper height, wherein the looper height command value represents a model of a looper control system including the looper motor speed control unit. Setting means for setting a variable to be set, a variable for designating a cutoff frequency of a response of the looper height control system , and a variable for adjusting a response of the looper height control. Control gain calculating means for substituting the set variables into a predetermined formula to obtain a control gain as a numerical value; control gain obtained by the control gain calculating means; and a height command of the looper set by the setting means Value, and
Control arithmetic means for calculating a rotation speed command value of the looper drive motor that causes the height of the looper to follow a looper height command value based on the detected height of the looper, and adding the rotation speed command value to the looper motor speed control means; A looper height control device comprising: