JP3262486B2 - Control device for tandem hot 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 tandem hot rolling mill for controlling the height of a looper disposed between stands of a tandem hot rolling mill and the tension between stands of a rolled material.

[0002]

2. Description of the Related Art Thickness and width are some of the evaluation criteria for final products in hot rolling and cold rolling. The tension applied to the material being rolled affects the thickness and width. Control to keep it at a certain value is performed. In particular, the rolling material in hot rolling is heated to a high temperature due to heat treatment, has a low deformation resistance, and is easily broken when the tension is large. If the tension is set low to prevent this breakage, the tension may become zero due to disturbance or erroneous setting. If the tension continues for a long time, a large loop may occur between the rolling mill stands and an accident may be caused. Therefore, a looper device is particularly provided in hot rolling to prevent loops from being generated between stands, while controlling the tension of the rolled material between stands and increasing the height of the looper from the viewpoint of improving the material passing property. Control.

In such control of the rolled material tension and the looper height, there are interference from the rolled material tension to the looper height and interference from the looper rotation speed to the tension. Conventional tension control includes a method of controlling the looper height by PID control without suppressing such interference. In the PID control of the looper height, the looper calculates the torque received from the weight of the looper itself, the weight of the rolled material and the rolled material tension (tension command value), and the torque when the looper accelerates and decelerates. By setting the current command value in the electric motor, the looper generates a force for pushing up the rolled material, and imparts tension to the rolled material. Therefore, it is an open loop in which only the setting is performed without feeding back the tension value.

On the other hand, a looper non-interference control which treats the above-mentioned interference system as a multivariable and adds a non-interference compensation device for suppressing the interference to independently control the tension of the rolled material and the height of the looper, Optimal control theory to control looper and rolled material tension in cooperation (LQ: Linear Quadratic)
The looper ILQ (Inv which can solve the inverse problem of LQ and obtain the control gain by a mathematical formula
There are multi-variable controls such as erse liner (Quadratic) control and H∞ control in which the robustness of the control system can be considered, and each is applied to an actual machine. Here, the robustness refers to a property that is hardly unstable even when noise is added to a control system or a control target changes.

[0005]

The multivariable control is based on the premise that both the rolled material tension and the looper angle are detected in order to take advantage of the respective characteristics. For this reason, it was difficult to apply multivariable control to a rolling mill without a tension meter. The tension between the i-th stand and the (i + 1) -th stand of the rolling mill is generated after the leading end of the rolled material is bitten by the (i + 1) -th stand, that is, after the (i + 1) -th stand passes. During this passing, the disturbance is very large, and the tension detection value obtained by the tension meter is not stabilized until a while after the i + 1st stand is passed. During this time, the tension value required for multivariable control cannot be obtained. Looper height PID that does not require
Control is needed.

Further, depending on the rolled material, tension control by multivariable control cannot cover all of them, and PID control of a sufficiently adjusted looper height may show better control performance, and tension detection is better. If this is not done, the multivariable control may malfunction, so the looper height PID
Control is also required for good control of the looper.

However, the PI of the above-mentioned looper height is
In the D control, since the feedback control is not performed, the tension value may not be controlled to the target value. In addition, when calculating a current reference value to be set in the looper motor, a current value required when accelerating or decelerating the looper is not known accurately, and thus, a fixed current value is generally added until now. In this case, for a rolled material having a small cross-sectional area, the specific gravity of the torque due to the fixed current value is larger than the torque due to the weight of the rolled material or the torque due to the tension,
There is a problem that the force of the looper for lifting the rolled material increases, and the tension value of the rolled material tends to be larger than the target value.

Further, the PID control of the looper height has no function of suppressing the mutual interference between the rolled material tension and the looper, and thus may be inferior to multivariable control in terms of responsiveness and stability. This is because the control response of the looper height control cannot be sufficiently increased for a reason. That is, when the tension and the looper system are represented by a transfer function, they are represented in a form including the secondary resonance system. Wherein the secondary resonant system becomes oscillatory as ζ damping constant of the resonance frequency omega _n is small. Therefore, the response of the control of the looper height is limited to less than about 1/4 of the resonance frequency omega _n, it must be kept even lower depending on the size of the damping factor zeta.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to control the height of a looper disposed between stands of a tandem rolling mill and the tension between stands of a rolled material with high precision. An object of the present invention is to provide a control device for a tandem hot rolling mill that enables stable control of a looper.

[0010]

According to the present invention, a looper current command value is calculated based on a tension target value and a looper height detection value, and the looper current command value is set in a looper current controller of a looper motor. A main current reference that calculates a main looper current reference that balances the torque received by the looper from the rolled material, the torque received from the rolled material tension, and the torque due to the looper's own weight as the looper current reference generator that controls the rolled material tension. Generating means, and auxiliary current reference generating means for calculating an auxiliary looper current reference that balances the torque required for accelerating and decelerating the looper. A looper current reference is calculated so as to be proportional.

According to another aspect of the present invention, the auxiliary current reference generating means includes a fixed current reference or a looper current reference determined so as to be proportional to the cross-sectional area of the rolled material, and a current value proportional to the speed at which the looper rises. To calculate an auxiliary looper current reference.

According to another aspect of the present invention, the auxiliary current reference generating means uses a fixed current reference or a looper current reference determined to be proportional to the cross-sectional area of the rolled material, and further calculates a roller height controller operated by a looper height controller. The auxiliary looper current reference is calculated by adding a current value proportional to the change in the speed command value of the motor.

According to another aspect of the present invention, a speed command value of a rolling mill main motor is calculated based on a looper height target value and a looper height detection value, and the calculated speed command value is used as the speed of the rolling mill main motor speed. A looper height controller configured to control the looper height by setting the controller, a looper current command value is calculated based on the tension target value and the looper height detection value, and the calculated looper current command value is output to the looper. When equipped with a looper current reference generator that controls the rolling material tension by setting the looper current controller of the electric motor, the tension received by the tension detector attached to the looper, or the torque received by the looper motor, the tension of the rolling material Tension calculating means for calculating and multiplying the calculated tension by a gain
The obtained value is used as the correction value based on the looper current.
From the looper current reference output from the current reference generator
At the same time, the looper height controller changes by this subtraction
By correcting the gain of the looper, the looper height control system
Tension compensation torque to change resonance frequency and damping constant
And a step.

Another invention calculates a speed command value of a rolling mill main motor based on a looper height target value and a looper height detection value, and uses the calculated speed command value as a rolling mill main motor speed controller. A looper height controller that controls the height of the looper by setting the looper current command value based on the tension target value and the looper height detection value, and calculates the calculated looper current command value of the looper motor. When equipped with a looper current reference generator to set the looper current controller to control the rolled material tension,
Tension calculating means for calculating the tension of the rolled material from the force received by a tension detector attached to the looper or the torque received by the looper motor, and a value obtained by multiplying the calculated tension by a gain.
Looper height control using the set value as the change amount of the main engine speed command value
At the same time as adding to the speed command value output from the
Corrects the gain of the looper height controller that changes due to addition
The resonance frequency of the looper height control system and the
A tension-dependent torque correcting means for changing the decay constant.

[0015]

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on preferred embodiments shown in the drawings. FIG. 1 is a block diagram showing the configuration of the first embodiment of the present invention together with a rolling mill to which the invention is applied. In the figure, a rolled material 1 is rolled in the order of an i-th stand rolling mill 2 and an (i + 1) -th stand rolling mill 3. 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 described below is installed between the stands. However, if the state between the two stands i to i + 1 can be considered, it can be easily extended to other stands. . Note that i is in the range of 1 ≦ i ≦ n−1.

When the looper 7 is provided between the i-th stand and the (i + 1) -th stand, the looper height converted into the angle of the looper arm is detected by the looper height detector 10. The detected current value I of the looper motor 8 that drives the looper 7 is fed back to the looper current controller 9. The looper current controller 9 controls the current detection value I to follow the current command value _Iref set by the looper current reference generator 12. On the other hand, the i-th stand rolling mill 2 and the (i + 1) -th stand rolling mill 3 are driven by rolling mill main motors (hereinafter referred to as main machines) 4 and 5, respectively. The speed of the i-th stand main machine 4 is controlled by the main machine speed controller 6. The same applies to the (i + 1) -th stand main machine 5, which is omitted here.

The looper height controller 11 is a looper height detector
The main engine speed command value is calculated so that the looper height (represented by the looper angle θ, hereinafter also referred to as looper angle) detected in step 10 follows the looper height target value _θref , and is added to the main engine speed set value. To the main machine speed controller 6 of the i-th stand. The looper current reference generator 12 includes a main current reference generator 13
And an auxiliary current reference generator 14. A looper driven by an electric motor is arranged between the i-th stand and the (i + 1) -th stand, and the geometric shape when the rolled material is lifted by the looper is as shown in FIG. The main current reference generator 13 calculates the main current command value I _ref1 by the following equation based on the geometric shape of FIG.

[0019]

(Equation 1) G: acceleration of gravity (mm / s ² ) = 9800 R ₁ : distance from the center of rotation of the looper to the center of the looper roll (mm) R ₃ : distance from the center of rotation of the looper to the center of gravity of the looper (mm) g _L : Gear ratio between looper machine and looper motor A: Cross-sectional area of rolled material (product of plate thickness and plate width) (mm ² ) α: Angle formed between pass line on i-stand side and rolled material (rad) beta: i + 1 the angle of the stand side of the pass line and rolled material (rad) theta: looper angle (rad) W _s: mass of the strip between stands (material length, cross sectional area, density product of) (kg) W _L : Looper weight (kg). If the looper angle θ and the target tension value t _fref are set by the equations (1) and (2),
The main current command value I _ref1 can be calculated.

FIG. 10 shows a configuration example of a control device of a tandem hot rolling mill that has been conventionally implemented. The main current reference generator 13 has a function of calculating the main current command value I _ref1 using the above equations (1) and (2). However, fixed current reference generator 15 corresponding to the auxiliary current reference generator 14 of this embodiment shown in FIG. 1, the current reference I ₀ of the fixed
Had only the ability to generate

Next, the auxiliary current reference generator 14 of this embodiment will be described below. The auxiliary current reference generator 14 calculates the auxiliary current reference _ICOM by any one of the following methods a, b, and c. a. The auxiliary current reference is stored in advance in a table divided according to the sectional area, and is taken out at the time of use. This auxiliary current reference may be determined using the arithmetic expression described in the following item b.
Moreover, you may store in a table, adjusting. b. It is calculated using the following equation.

[0022]

(Equation 2) Here, I _COM : auxiliary current reference I _ST : standard current reference A _ST : standard cross-sectional area It is also possible to set an upper limit and a lower limit for the above-described auxiliary current reference I _COM .

[0023] As in the conventional apparatus shown in FIG. 10, when a current reference I ₀ of the fixed, will be substantially constant tension value regardless of the cross-sectional area of the rolled material is plus, a large cross sectional area The tension value of the small area material was likely to be larger than the target value compared to the material. However, as described in the above item a or b, when the auxiliary current reference _ICOM proportional to the cross-sectional area is used, the phenomenon that the tension value becomes larger than the target value for the rolled material having a small cross-sectional area is reduced. be able to. c. It is calculated using the following equation. I _COM = K _COM × ω _L + I _BASE (4) where I _COM : auxiliary current reference K _COM : gain ω _L : looper angular velocity I _BASE : current reference value of item a or b, or fixed current reference Value. In this case, it is possible to set upper and lower limits on the auxiliary current reference _ICOM given by the equation (4).

Using the above equation (4), the auxiliary current reference I _COM
In the case where there is a loop in the rolled material between stands by calculating, it is necessary to quickly raise the looper and remove the loop of the rolled material in a short time, and the auxiliary in proportion to the looper angular velocity By outputting the current reference,
The loop can be eliminated faster.

FIG. 3 is a block diagram showing the configuration of the second embodiment of the present invention, in which a control system for looper height and tension is modeled and expressed. Here, in the height control of the looper, the looper angle to be controlled and the main machine speed as an operation amount are in a non-linear relationship, and are converted into a rolled material loop amount 1 between stands having a linear relationship with the main machine speed, A looper height control system is configured using the loop amount l. A non-linear function F ₂ (θ) for converting the looper angle θ into the loop amount l is represented by the following equation (5).

[0026]

(Equation 3) The loop amount l is: l = F ₂ (θ) (6) where L: distance between stands (mm) L ₁ : distance (m) from the center of rotation of the looper to the i-th stand
m).

[0027] In FIG. 3, block 20 corresponds to the looper height control unit 11 in FIG. 1, the looper angle target value theta _ref,
(5) into a loop amount target value l _ref using, also converts the looper angle θ to the loop amount l. The looper height controller 21 is composed of a PI control system, and is represented by a proportional control gain K _P , an integral control gain K _I , and a total gain K _{T. The} looper height controller 21 calculates the deviation between the looper angle target value θ _ref and the loop amount l by ( K _P + K _I / s) _KT multiplied by the main engine speed command value V _Rref
Is output.

The main engine speed control system 22 expresses the speed response of the main engine using a first-order lag time constant T _v , and is transmitted by a combination of the main engine speed controller 6 and the i-th stand main engine 4 in FIG. Expressed as a function. This main engine speed control system 22
Material speed V by a block 23 which is represented by using a transfer roll peripheral obtained by multiplying the function speed variation V _R advanced rate f of
Converted to _s . The material velocity V _s , the loop velocity change ω _L × dF ₂ (θ) / dθ of the rolled material due to the looper angular velocity ω _L represented by the block 26, and the tension by the tension feedback coefficient K ₁₀ represented by the block 25 The sum of the change to the material velocity given by becomes the tension t _f through the block 24 containing the integrator. E in the block 24 is the Young's modulus of the rolled material. The tension t _f appears as a tension torque T _T applied to the looper motor. The block 27 expresses this, and F ₃ (θ) described therein is expressed by the following equation.

[0029]

(Equation 4) Block 28 is a transfer function from the torque applied to the looper motor to the rotational speed omega _L of the looper motor, since omega _L becomes looper angle θ is integrated, this block 29
Is represented by A block 30 represents the looper damping Z, and a block 31 is a function F ₁ (θ) representing a relationship from the looper angle θ to the torque of the looper motor, and is represented by the following equation.

[0030]

(Equation 5) Block 32 corresponds to looper current reference generator 12 in FIG. Block 33 is a representation of the looper current control system of the time constant T _cc at a primary delay, block 34 represents the influence coefficient (referred to as torque constant) [Phi when the looper current I becomes the torque T. Blocks 28, 33, and 34 in FIG. 3 correspond to the looper current controller 9 and the looper motor 8 in FIG. As described above, the reason why the auxiliary current reference is required is that it is necessary to compensate for the torque when the looper is accelerated / decelerated. However, it is generally difficult to calculate the torque required for acceleration / deceleration in advance.

The acceleration and deceleration torque T _A is represented by the following formula.

[0032]

(Equation 6) Here, J is the inertia of the looper (kgm ² ). The amount to follow the change of the rolled material speed V _s generated through blocks 22 and 23 in FIG. 3, the looper angular velocity omega _L
, Through the block 26, the tension is unchanged. The rolling material speed V _s that changes through the block 26 is expressed by the following equation.

[0033]

(Equation 7) As the material speed changes, the tension changes and so does the force on the looper, which raises or lowers the looper. The torque required for raising and lowering the looper is the acceleration / deceleration torque.
Solving equation (10) for the looper angular velocity ω _L , differentiating both sides with time, and then multiplying both sides by J gives the following equation.

[0034]

(Equation 8) As a result, it can be seen that the acceleration / deceleration torque T _A is represented by the inertia J of the looper, the time change of the material speed, and the angle differential value of the function F ₂ (θ). However, since it is difficult to measure the speed of the rolled material, a time change of the main machine speed command value _VRref output from the looper height controller is used as an alternative. Thus, instead of the auxiliary current reference I _{CO M} auxiliary current reference generating means 14 shown in FIG. 1 has been described above, it can be seen that if the output of the auxiliary current reference I _COM shown in the following equation.

[0035]

(Equation 9) A block 35 in FIG. 3 generates a time change of the main engine speed command value V _Rref , and a block 36 represents a gain.

Thus, according to the second embodiment, the acceleration / deceleration torque of the looper in the conventional PID control of the looper height can be compensated, and the tension is set to the target value because the constant auxiliary current reference is set. It will not be larger. As a result, it is possible to reduce the adverse effect on the plate thickness and the plate width due to over tension.

In the second embodiment shown in FIG. 3, the transfer function G (s) from the main engine speed command value V _Rref to the looper angle θ is as follows.

[0038]

(Equation 10) Here, ω _n : resonance frequency ζ: damping constant. The resonance frequency omega _n is represented by the following equation.

[0039]

[Equation 11] The attenuation constant ζ is expressed by the following equation.

[0040]

(Equation 12) In the looper height control, the resonance frequency ω
_It is necessary to suppress the response to about 1/3 to 1/5 of _n .
Generally, the resonance frequency ω _n = 5 to 10 rad / s,
The control response of the looper height is about 2 to 4 rad / s.
In order to speed up the response of the looper height control system, it is desirable that the resonance frequency be in a high frequency range, and that the larger the damping constant, the more difficult it is to vibrate.

The following methods A, B, and C can be considered as methods for changing the resonance frequency and the attenuation constant. A. To change the influence coefficient F ₂ to the material speed from the looper speed. B. To change the influence coefficient F ₃ from the tension to Rupatoruku. C. To change the tension feedback coefficient K _10.

Among them, item A is described in Japanese Patent Application Laid-Open No. 7-1.
No. 6632, the B and C
Items will be described.

The above-described looper height PID control is often used in conjunction with the looper multivariable control, and a tension detector may be installed to monitor the tension of the rolled material. In many cases, the tension detection value can be used even in the PID control of the looper height.

FIG. 4 is a block diagram showing the configuration of the third embodiment of the present invention corresponding to the method of the above-mentioned item B, together with a rolling mill to be applied. In the figure, the same elements as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. Here, the tension calculating means 17 calculates the tension of the rolled material based on the output signal of the tension detector 16 such as a load cell. The tension component torque correcting means 18 corrects the current reference _Iref set in the current controller 9 of the looper motor using the calculated tension. This correction method will be described below with reference to FIGS.

From equation (14), if the influence coefficient F ₃ can be changed, the resonance frequency can be changed.
Now, it is assumed that the gain K _F3 ^* is added to increase F ₃ as in the following equation. F ₃ → F ₃ + K _F3 ^* (16) In this case, the resonance frequency ω _n increases as in the following equation.

[0046]

(Equation 13) This relationship is modeled and expressed as shown in FIG. That is, the block 37 is connected in parallel with the block 27. However, the product of the rolled material tension t _f and the gain K _F3 ^* is directly applied to the load torque T of the looper motor.
Therefore, as shown in FIG. 6, the value obtained by multiplying the rolled material tension t _f by the gain K _{F3 of the} block 38 is _fed back to the current command value I _{ref as shown} in FIG. However, also changes the gain of the transfer function G (s) by changing the impact factor F _3. The transfer function G (s) in this case is as follows.

[0047]

[Equation 14] Here, changing the F ₃ with similarly (14) in the case of Z, the gain of G (s) is changed. Therefore, in order to obtain a flush control response as before the F _3, it is necessary to change the total gain K _T of the looper height control to the total gain K _T ^* follows the height control unit .

[0048]

(Equation 15) In FIG. 4, the broken line from block 18 to block 11 means that the total gain of the looper height control is corrected by equation (19). Thus, according to the third embodiment, it is possible to increase the response of the looper height control by changing the resonance frequency and the damping constant in the looper height control, and it is possible to control the looper with high speed and stability. In calculating the tension of the rolled material, the calculation was performed based on the output of the tension detector 16 in the third embodiment.
Alternatively, it can be calculated from the torque received by the looper motor.

FIG. 7 is a block diagram showing a configuration of the fourth embodiment of the present invention corresponding to the method of the above-mentioned item C, together with a rolling mill to be applied. In the figure, the same elements as those in FIG. 1 or FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted. Also in this case, the tension calculating means 17 calculates the tension of the rolled material based on the output signal of the tension detector 16 such as a load cell. The tension generating gain correction means 19 calculates the change amount of the main engine speed command value using this tension, and adds it to the main engine speed command value. The calculation method of the change amount of the main engine speed command value by the tension generation gain correction means 19 will be described below with reference to FIGS.

[0050] (14) As is apparent from the equation, if it is possible to change the tension feedback coefficient K _10, it is possible to change the resonance frequency. That is, as shown in FIG. 8 that models the control system of the tension and the looper height can indirectly changed from a parallel connection of block 39 to the block 25 of K _10. This means that by increasing the K ₁₀ as follows. By increasing the _{K 10 → K 10 + K K} * ... (20) K 10, the resonance frequency ω _n is increased as shown in the following equation.

[0051]

(Equation 16) Further, the damping constant ζ also increases as in the following equation.

[0052]

[Equation 17] However, since the product of the tension and the gain K _K ^* cannot be directly returned to the material speed, as shown in FIG.
Block 40 returns to the main engine speed command value V _Rref .
Here, increasing the K ₁₀ in the third likewise (18) in the embodiment of the gain of the transfer function G (s) is reduced.
Therefore, in order to obtain a control response for the same looper height as before the change of K _10, the total gain of the looper height controller K _T
Needs to be increased as K _T ^{* in} the following equation.

[0053]

(Equation 18) Here, K _T ^* is the total gain of the height control after the change. In FIG. 7, a broken line drawn from the block 19 to the block 11 indicates that the looper height control total gain is corrected by the equation (23). Thus, K ₁₀
By adding K _K ^* to the above, the following effects a and b can be obtained. I. When K ₁₀ increases, the gain from the material velocity to tension (1 / K ₁₀₎ is reduced, the tension fluctuation is reduced. B. If the tension increases, the speed of the main engine increases, which is effective as a tension control as a means other than the control of the tension by the looper current.

Thus, according to the fourth embodiment, it is possible to increase the response of the looper height control by changing the resonance frequency and the damping constant in the looper height control, and it is possible to control the looper with high speed and stability. become.

As described above, the present invention has been described based on the specific embodiments. However, these embodiments can be used not only individually but also in combination with a plurality of embodiments. Further, in each of the above embodiments, the case where the looper is driven by the looper motor has been described. However, the present invention is not limited to this, and can be applied to a system driven by a hydraulic device.

[0056]

As is apparent from the above description, according to the present invention, when setting the acceleration / deceleration torque of the looper,
Since the auxiliary current criterion proportional to the cross-sectional area of the rolled material was used,
It is possible to prevent an increase in tension at a small cross-sectional area, which is remarkable in the conventional PID control, and thereby it is possible to eliminate an adverse effect on the sheet thickness and the sheet width due to excessive tension in a small cross-sectional area material.

According to another aspect of the present invention, since the auxiliary current reference proportional to the looper angular velocity is used, it is possible to quickly remove the loop generated in the rolled material between the stands, and to perform a stable operation. Can be.

According to another aspect of the present invention, the acceleration / deceleration torque of the looper in the conventional PID control of the looper height can be compensated, and a constant current reference is always set so that the tension becomes larger than the target value. Will not be. As a result, it is possible to reduce the influence of the over tension on the plate thickness and the plate width.

According to another aspect of the present invention, tension calculating means
Multiply the gain calculated by
Output from looper current reference generator as current reference correction value
At the same time as subtracting from the looper current reference
The looper height controller gain
Thus, the resonance frequency and the damping constant in the looper height control can be changed to increase the looper height control response, and high-speed and stable looper control can be performed. Further, according to another invention, the tension calculating means
The value obtained by multiplying the calculated tension by the gain is the main engine speed.
Output from the looper height controller as the change amount of the command value
At the same time as adding to the speed command value,
By adjusting the gain of the looper height controller, the resonance frequency and damping constant in the looper height control can be changed, and the looper height control response can be increased, enabling high-speed and stable looper control. become.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of the present invention, together with a rolling mill to be applied.

FIG. 2 is a diagram showing a geometric relationship between a looper angle and a passing shape of a rolled material for explaining an operation of the first embodiment of the present invention.

FIG. 3 is a block diagram showing a detailed configuration of a second embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a third embodiment of the present invention, together with a rolling mill to which the invention is applied.

FIG. 5 is a block diagram for explaining the principle of the third embodiment of the present invention.

FIG. 6 is a block diagram showing a detailed configuration of a third embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a fourth embodiment of the present invention together with a rolling mill to which the present invention is applied;

FIG. 8 is a block diagram for explaining the principle of the fourth embodiment of the present invention.

FIG. 9 is a block diagram showing a detailed configuration of a fourth embodiment of the present invention.

FIG. 10 is a block diagram showing a configuration of a control device of a conventional tandem hot rolling mill together with a rolling mill to be applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rolled material 2 i-th stand rolling machine 3 i + 1st stand rolling machine 4 i-th stand rolling machine main motor 5 i + 1st stand rolling machine main motor 6 main machine speed controller 7 looper 8 looper motor 9 looper current controller 10 looper height Detector 11 Looper height controller 12 Looper current reference generator 13 Main current reference generator 14 Auxiliary current reference generator 15 Fixed current reference generator 16 Tension detector 17 Tension calculation means 18 Tension torque correction means 19 Tension generation gain Correction means

Claims (8)

(57) [Claims] 1. A control device for a tandem hot rolling mill for controlling a height of a looper disposed between stands of a tandem hot rolling mill and a tension of a rolled material between the stands, wherein the stand rolling is performed according to a speed setting value. A main motor speed controller for controlling the speed of the main motor, and a main motor speed command value for causing the looper height detection value to follow the looper height target value are calculated, and the main motor speed controller is operated by the speed command value. A looper height controller for correcting the applied speed set value, and a looper for calculating a looper current command value for causing the tension of the rolled material to follow the tension target value based on the target tension value of the rolled material and the detected looper height value. A current reference generator, a looper current controller for controlling the current of the looper motor according to the looper current command value, wherein the looper current reference generator receives a torque that the looper receives from the rolled material, A main looper current reference that balances the sum of the torque received from the rolled material tension and the torque due to the looper's own weight is one of the cross-sectional area of the rolled material, the rising speed of the looper, and the change in the speed command value. Alternatively, a control device for a tandem hot rolling mill, wherein the correction is performed based on an auxiliary looper current reference obtained in consideration of a plurality of requirements. 2. A main current reference for calculating a main looper current reference that balances a torque received by a looper from a rolled material, a torque received from a rolled material tension, and a torque due to the looper's own weight. Generating means, and auxiliary current reference generating means for calculating an auxiliary looper current reference determined to be proportional to the cross-sectional area of the rolled material, and adding the main looper current reference and the auxiliary looper current reference. 2. The control device for a tandem hot rolling mill according to claim 1, wherein the value obtained as a result is output as a looper current command value. 3. A main current reference for calculating a main looper current reference that balances the sum of the torque received by the looper from the rolled material, the torque received from the rolled material tension, and the torque due to the looper's own weight. Generating means for calculating an auxiliary looper current reference by adding a value determined to be proportional to the cross-sectional area of the rolled material and a value determined to be proportional to the speed at which the looper rises; The control device for a tandem hot rolling mill according to claim 1, further comprising: outputting a value obtained by adding the main looper current reference and the auxiliary current reference as a looper current command value. 4. A main current reference for calculating a main looper current reference such that the looper current reference generator balances a torque received by the looper from the rolled material, a torque received from the rolled material tension, and a torque due to the looper's own weight. Generating means, a value determined to be proportional to the cross-sectional area of the rolled material and a value determined to be proportional to the speed at which the looper rises and proportional to a change in a speed command value calculated by the looper height controller. And an auxiliary current reference generating means for calculating an auxiliary looper current reference by adding a value to the looper current command. A value obtained by adding the main looper current reference and the auxiliary looper current reference is referred to as a looper current command. The control device for a tandem hot rolling mill according to claim 1, which outputs the value as a value. 5. A main current reference for calculating a main looper current reference such that the looper current reference generator balances a torque received by the looper from the rolled material, a torque received from the rolled material tension, and a torque due to the looper's own weight. Generating means for calculating an auxiliary looper current reference by adding a fixed value and a value determined so as to be proportional to the speed at which the looper rises, the main looper current reference The control device for a tandem hot rolling mill according to claim 1, wherein a value obtained by adding the reference value and the auxiliary looper current reference is output as a looper current command value. 6. A main current reference for calculating a main looper current reference that balances the torque received by the looper from the rolled material, the torque received from the rolled material tension, and the torque due to the looper's own weight. Generating means for adding an auxiliary looper by adding a fixed value and a value determined so as to be proportional to the speed at which the looper rises and a value proportional to a change in the speed command value calculated by the looper height controller; 2. A tandem according to claim 1, further comprising auxiliary current reference generating means for calculating a current reference, wherein a value obtained by adding the main looper current reference and the auxiliary looper current reference is output as a looper current command value. Control device for hot rolling mill. 7. A control device for a tandem hot rolling mill for controlling a height of a looper disposed between respective stands of a tandem hot rolling mill and a tension of a rolled material between the stands, wherein the stand rolling is performed according to a speed setting value. A main motor speed controller for controlling the speed of the main motor, and a main motor speed command value for causing the looper height detection value to follow the looper height target value are calculated, and the main motor speed controller is operated by the speed command value. A looper height controller for correcting the applied speed set value, and a looper for calculating a looper current command value for causing the tension of the rolled material to follow the tension target value based on the target tension value of the rolled material and the detected looper height value. A current reference generator, a looper current controller for controlling the current of the looper motor in accordance with the looper current command value, and a force received by a tension detector attached to the looper, or a force received by the looper motor. Looper collector and tension calculating means, a value obtained by multiplying the gain of the calculated tension calculating the tension of the rolled material from the torque
Output from the looper current reference generator as a flow reference correction value.
Subtract from the applied looper current reference and at the same time
Corrects the gain of the looper height controller that changes due to the calculation
A tension-dependent torque correcting means for changing the resonance frequency and the damping constant of the looper height control system, thereby controlling the tandem hot rolling mill. 8. A control device for a tandem hot rolling mill for controlling a height of a looper disposed between stands of a tandem hot rolling mill and a tension of a rolled material between stands, wherein the stand rolling is performed according to a speed setting value. A main motor speed controller for controlling the speed of the main motor, and a main motor speed command value for causing the looper height detection value to follow the looper height target value are calculated, and the main motor speed controller is operated by the speed command value. A looper height controller for correcting the applied speed set value, and a looper for calculating a looper current command value for causing the tension of the rolled material to follow the tension target value based on the target tension value of the rolled material and the detected looper height value. A current reference generator, a looper current controller for controlling the current of the looper motor in accordance with the looper current command value, and a force received by a tension detector attached to the looper, or a force received by the looper motor. Main engine speed and tension calculating means for calculating the tension of the rolled material, a value obtained by multiplying the gain of the calculated tension from the torque
Output from the looper height controller as the change amount of the command value
At the same time as the speed command value
Compensating the gain of the looper height controller
Accordingly, a control device for a tandem hot rolling mill, comprising: a tension component torque correcting means for changing a resonance frequency and a damping constant of a looper height control system.