JPH067813A - Motor controller for driving rolling mill - Google Patents

Abstract

PURPOSE:To improve accuracy and stability of rolling condition control and to improve the quality of material to be rolled, etc., by improving the responsiveness of driving force control of a motor for drive a rolling roll. CONSTITUTION:A rolling torque calculating device 12 calculates rolling torque G while using a specified calculating formula from rolling condition measurement values measured by a rolling condition measuring instrument 10, measurement values of rolling load P, tensile force T between stands, thickness (h), etc., for instance. A motor electric power controller 20 controls the driving force of the motor for driving the rolling roll according to at least the rolling torque G. Accordingly, when the driving force control of the motor is affected by the change of the rolling condition, the influence can be immediately controlled by controlling the driving force of the motor according to the measurement values of the rolling condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor control device for driving a rolling mill, which controls the driving force of the electric motor when the material to be rolled is sandwiched between rolling rolls driven by the electric motor and rolled. In particular, it is possible to improve the responsiveness of the driving force control of the electric motor that drives the rolling rolls, thereby improving the precision and stability of rolling condition control, and improving the quality of the material to be rolled. The present invention relates to a motor drive motor control device.

[0002]

2. Description of the Related Art For example, in a continuous rolling mill, the rotational speed command value of the rolling roll of each rolling stand, that is, the speed command value of each rolling stand is set so that the tension between the rolling stands becomes a specified value. It When the speed command value is determined, the electric motor power control device provided for each electric motor of each rolling stand performs feedback control of the rotation speed of the electric motor according to the speed command value.

In this feedback control of the rotation speed of the electric motor, a torque command is calculated from the deviation between the detected speed value detected by a speed detector such as a pulse generator attached to the electric motor and the speed command value. The calculation for obtaining the torque command is calculated, for example, in a speed compensator (PI compensation) in the electric motor power control device. Further, other control parameters are added to the torque command, and for example, the voltage command value is calculated and obtained in the torque regulator at the stage subsequent to the speed compensator. When the voltage command value is calculated in this way, the voltage of the electric motor that drives the rolling rolls is adjusted by, for example, the voltage adjuster at the stage subsequent to the torque adjuster, and the driving force of the electric motor is thereby controlled. .

Regarding the driving force control of the electric motor for driving such a rolling roll, various techniques have been disclosed in order to improve the precision and stability of the rolling condition control.

For example, Japanese Patent Laid-Open No. 1-170510 discloses a technique relating to an inter-stand tension control device for a continuous rolling mill that corrects the speed reference of an electric motor for driving the rolling mill so that the inter-stand tension becomes constant. . This is provided with a first arithmetic circuit that inputs an armature current signal and a speed signal of the electric motor and uses the minimum dimension observer of a basic equation simulating a system including the rolling mill and the electric motor to obtain the rolling torque. . A second arithmetic circuit for obtaining a speed correction amount for correcting the speed reference, based on the rolling load signal of the rolling mill, the speed signal of the electric motor, and the rolling torque obtained by the first arithmetic circuit. Equipped with. According to the technique disclosed in Japanese Patent Application Laid-Open No. 1-170510, even if the rolling conditions change, the rolling torque can be accurately detected, which enables highly accurate rolling.

[0006]

However, in the conventional rolling mill driving electric motor control device, for example, when the plate thickness of the material to be rolled on the entry side is suddenly changed, the rolling mill driving electric motor control device is provided. In some cases, the rotation speed of the electric motor controlled by was fluctuated, and the driving force control thereof became unstable. If the deviation of the actual rotation speed of the rolling roll of the rolling mill from the speed command value increases or fluctuates, the plate thickness of the rolled material on the exit side of the rolling mill fluctuates, resulting in product quality. It becomes an upper problem.

Further, in order to reduce the deviation between the actual rotation speed of the rolling roll and the speed command value, the speed compensator as described above in the electric motor power controller and the torque adjustment as described above are provided. It is also possible to increase the gain of the vessel. However, such an increase in gain has mechanical restrictions (problem of vibration) and restrictions of electric motor (problem of commutation of direct-current motor), so that good effects may not be obtained. Therefore, the conventional rolling mill driving electric motor control device has a problem that the responsiveness of the driving force control of the electric motor cannot be sufficiently improved.

Further, in the Japanese Patent Laid-Open No. 1-170510, the rolling torque is obtained from the armature current signal and speed signal of the electric motor by the first arithmetic circuit, but sufficient accuracy can be obtained. could not. this is,
This is because the first arithmetic circuit estimates the rolling torque only by the speed and current of the electric motor. Also, the purpose is
This is for keeping the tension between the stands constant and suppressing the torsional shaft vibration.

The present invention has been made to solve the above-mentioned conventional problems, and improves the response of the driving force control of the electric motor for driving the rolling rolls, thereby improving the precision and stability of the rolling condition control. It is an object of the present invention to provide an electric motor control device for driving a rolling mill which can improve the quality of a material to be rolled.

[0010]

SUMMARY OF THE INVENTION The present invention is directed to a rolling mill driving electric motor control for controlling the driving force of the electric motor when rolling the material to be rolled by the opposed rolling rolls driven by the electric motor. The above object is achieved by providing the apparatus with a rolling torque calculation device that calculates the rolling torque G from the actual measurement value of the rolling conditions and an electric motor power control device that controls the driving force of the electric motor according to at least the rolling torque G. It was done.

[0011]

The present invention has been made by studying the factors affecting the driving force control in order to improve the response of the driving force control of the electric motor for driving the rolling rolls.
For example, when the driving force control is a feedback control of the actual rotation speed of the rolling roll with respect to a predetermined speed command value, the plate thickness of the material to be rolled on the entry side suddenly fluctuates or the acceleration / deceleration of the rolling mill is decelerated. When the friction coefficient changes due to the change of the rolling speed, the deviation of the actual rotation speed of the rolling roll from the speed command value increases. This is the conventional rolling mill drive motor control device as described above,
That is, in a motor control device that performs feedback control with a speed detector such as a pulse generator attached to the motor, the gain may not be sufficiently increased.

For this reason, in the present invention, the rolling condition affecting the driving force control of the electric motor for driving the rolling roll is measured, and the rolling torque G is calculated from the measured rolling condition. The rolling torque G is a parameter of the same dimension as the driving force (torque) of the electric motor that drives the rolling rolls. Therefore, in the present invention, the responsiveness of the driving force control is improved by controlling the driving force of the electric motor that drives the rolling roll in accordance with the rolling torque G obtained from the actual measurement value of the rolling conditions. .

Conventionally, some rolling conditions fluctuate,
Compared with the case where the actual rotation speed of the rolling roll that has fluctuated with this is detected and the driving force control of the electric motor is performed, the present invention is directed to the direct electric motor according to the fluctuation of the rolling condition that affects the driving force control. Driving force control is performed.
Therefore, the response can be improved as compared with the conventional one.

FIG. 1 is a block diagram showing the gist of the present invention.

As shown in FIG. 1, the rolling mill driving electric motor control device of the present invention mainly comprises a rolling torque calculation device 12 and an electric motor power control device 20. The rolling mill driving motor control device includes a rolling condition measuring device 10.

The rolling torque calculation device 12 calculates the rolling torque G from the actual measurement value of the rolling condition measured by the rolling condition measuring device 10. The present invention relates to the rolling torque calculation device 1
The specific configuration of _{No. 2} is not limited, and the rolling torque G is calculated from the measured values of the rolling load P of the rolling mill, the inter-stand tension T, the inlet side plate thickness h ₁ and the outlet side plate thickness h ₂ , for example. If

For example, it is known that when the rolling load is P and the torque arm is x _t , the rolling torque G can be calculated by the following equation.

G = P x _t (1)

Further, in the above formula (1), the rolling torque G can be expressed by the following formula when the tension between stands is also taken into consideration.

G = P x _t + (T _{i-1, i} −T _{i, i + 1} ) R / 2 (2)

In the above equation (2), T _{i-1, i}
Is the tension between the stands in front of the corresponding rolling stand, and T
_{i and i + 1} are tensions between stands behind the corresponding rolling stand, and R is a work roll diameter. The torque arm x _t
Can be expressed as:

X _t = αL _d = α (R′Δh) ^1/2 (3)

In the above equation (3), α is a predetermined constant, R'is a flat roll diameter, and Δh is a difference in plate thickness obtained by subtracting the plate thickness on the outgoing side from the plate thickness on the incoming side of the corresponding rolling stand. , L _d is the contact arc length. The flat roll diameter R'in the equation (3) can be expressed by the following equation.

R ′ = R [1 + {(Co P) / Δh}] (4)

[0025] Here, Co is "16 (1- r ²⁾ /
πE ”(r: Poisson's ratio, E:
Young's modulus). Here, when the above equation (4) is substituted into the above equation (3), the following equation is obtained.

X _t = α {R (Δh + Co P)} ^1/2 (5)

When the above equation (5) is substituted into the above equation (2), the following equation is obtained.

G = αP {R (Δh + CoP)} ^1/2 + (T _{i-1, i} −T _{i, i + 1} ) R / 2 (6)

The rolling torque G is the standard rolling torque Go.
Is defined by the following equation (7), it is known that the ratio of the rolling torque G to the reference rolling torque Go, that is, G / G ^o can be expressed by the following equation (8). There is.

Go = bk RΔh (7) G / Go = 1.05 + (0.07 + 1.32s) μ (R '/ h) ^1/2 -0.85s (8)

Here, b is the strip width of the material to be rolled, k is the two-dimensional deformation resistance, s is the rolling reduction, and μ
Is the coefficient of friction.

As described above, the rolling torque G can be calculated from the actual measurement value of the predetermined rolling condition by various calculation formulas. For example, it can be calculated from the formula (1), the formula (6), and the formula (8).

Although the present invention does not specifically limit the rolling torque calculation device 12, the rolling torque calculation device 12 calculates these calculation formulas by a microcomputer or the like, for example. Good. Further, the rolling condition measuring device 10 is not particularly limited,
It is determined by the actual measurement value of the rolling conditions required by the rolling torque calculation device 12. The rolling condition measuring device 10 is
For example, a rolling load meter such as a load cell, a tensiometer for measuring the tension between the stands, and a plate thickness meter for measuring the entrance side plate thickness and the exit side plate thickness.

The electric motor power control device 20 controls the driving force of the electric motor for driving the rolling roll according to at least the rolling torque G calculated by the rolling torque calculation device 12. Although the present invention does not limit the driving force control, for example, the actual rotation speed of the rolling roll may be feedback-controlled so that the speed command value is obtained. The tension between the stands may be feedback-controlled.
Further, the present invention does not specifically limit the control of the electric motor performed by the electric motor power control device 20, but may control the voltage of the electric power supplied to the electric motor and control the electric current. Alternatively, when the electric motor is an induction motor, it may control the power supply frequency. or,
The rolling torque G input from the rolling torque calculation device 12 to the electric motor power control device 20 may be an absolute value according to an actual physical quantity, or a deviation from a predetermined value, that is, a rolling torque deviation. May be

As described above, according to the present invention, the driving force control of the electric motor can be performed in accordance with the actual measurement value of the rolling condition that has an influence on the driving force control of the electric motor, and the responsiveness of the driving force control of the electric motor can be improved. Can be improved. As a result, the precision and stability of rolling condition control can be improved, and the quality of the material to be rolled can be improved.

[0036]

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

FIG. 2 is a block diagram showing the configuration of a rolling mill driving electric motor control device to which the present invention is applied.

In FIG. 2, the rolling mill driving electric motor control device of the present embodiment, the i-th stand controlled by the rolling mill driving electric motor control device, and the next stage of the i-th stand are shown. The i + 1 stand is shown.

In FIG. 2, the i-th stand and the i-th stand
Each of the +1 stands includes a rolling roll 40 and a backup roll 42. Also, the above
A rolling load cell 54 is attached to the i stand. In front of the i-th stand, a plate thickness gauge 50a for measuring the entrance side plate thickness, and a tensiometer 52a for measuring inter-stand tension between the (i-1) th stand and the i-th stand.
And are installed. Also, behind the i-th stand,
A plate thickness gauge 50b for measuring the outgoing plate thickness of the i-th stand,
A tensiometer 52b for measuring the inter-stand tension between the i-th stand and the (i + 1) -th stand is arranged.

As shown in FIG. 2, the rolling mill driving electric motor control device of the above embodiment mainly comprises a rolling torque calculation device 12a, a model calculation calculator 30, and an electric motor power control device 20a. There is. Further, the electric motor power control device 20a includes a speed compensator 22 and a torque adjuster 2
4 and a voltage regulator 26.

The rolling torque calculation device 12a inputs the actual measured value h _{1 of} the incoming side plate thickness and the actual measured value h _{2 of the} outgoing side plate thickness respectively measured by the plate thickness gauges 50a and 50b, and the tensiometers 52a and 52b respectively. The inter-stand tensions T _{i−1, i} and the inter-stand tensions T _{i, i + 1} measured by the above are input, and the rolling load measured value at the i-th stand measured by the rolling load meter 54 is measured. P is input. The rolling torque calculation device 12a uses the plate thickness measurement values h ₁ ,
The plate thickness difference Δh is obtained from h ₂ . Also, the plate thickness difference Δh
And the inter-stand tensions T _{il, i} , T _{i, i + 1} and the rolling load measured value P, the rolling torque G is calculated using the equation (6).

In the present embodiment, the plate thickness difference Δh is obtained from the measured plate thickness values h ₁ and h ₂ , but the calculated value of the plate thickness difference Δh calculated by the model calculating computer 30 is Even if used, almost sufficient accuracy can be obtained.

The electric motor power control device 20a includes the
The driving force of the electric motor 44 for driving the rolling roll 40 of the i stand is feedback-controlled while detecting the actual rotation speed of the rolling roll 40 by the pulse generator 46 attached to the electric motor 44.

The speed compensator 22 of the electric motor power controller 20a obtains the deviation between the speed command 14a and the actual rotation speed of the rolling roll 40 of the i-th stand detected by the pulse generator 46. Also, the speed compensator 22
Calculates the torque command value from the calculated speed deviation.

The torque adjuster 24 obtains a voltage command value according to the torque command value output from the speed compensator 22 and the rolling torque G output from the rolling torque calculation device 12a. A switch SW is provided on the path from the rolling torque calculation device 12a to the torque adjuster 24 for inputting the rolling torque G. When the switch SW is off, the torque adjuster 24 obtains the voltage command value only according to the torque command value.

The voltage regulator 26 regulates the voltage of the electric power supplied to the electric motor 44 according to the voltage command value output from the torque regulator 24.

3 and 4 are graphs showing the effect of this embodiment.

In FIG. 3, when the switch SW of FIG. 2 is turned off and control is performed without using the rolling torque G calculated by the rolling torque calculation device 12a, the rolling roll of the i-th stand is controlled. 40 rolling torque,
The measured speed value of the rolling roll 40 is shown. or,
In FIG. 4, when the switch SW of FIG. 2 is turned on and the rolling torque G calculated by the rolling torque calculation device 12a is used for control, the rolling roll 40 of the i-th stand is controlled. The rolling torque and the measured speed value of the rolling roll 40 are shown.

In both of FIGS. 3 and 4, the rolling torque rapidly changes at time t ₁ (reference numeral A1 in FIG. 3 and reference numeral A3 in FIG. 4). At this time t ₁ , the measured speed value fluctuates when the rolling torque G calculated by the rolling torque calculation device 12a is not used (reference A2 in FIG. 3). On the other hand, as shown in FIG. 4, when the rolling torque G calculated by the rolling torque calculation device 12a is used for control, the measured speed value does not fluctuate even if the rolling torque fluctuates (see FIG. 4 symbol A4).

As described above, in this embodiment, the rolling torque G calculated by the rolling torque calculating device 12a is calculated.
By controlling the driving force (rotational speed) of the electric motor 40 while using, the control response and control accuracy can be improved.

Further, it has been known that the relationship between the deviation amount of the rotation speed of the rolling roll 40 and the deviation amount of the product sheet thickness after rolling has a relationship as shown in the graph of FIG. Therefore, by reducing the deviation amount of the actual rotation speed of the rolling roll 40 according to the present embodiment, it is possible to reduce the deviation amount of the thickness of the product to be rolled and improve the product quality. it can.

[0052]

As described above, according to the present invention, the responsiveness of the driving force control of the electric motor for driving the rolling rolls is improved, thereby improving the precision and stability of the rolling condition control,
An excellent effect that the quality of the rolled material can be improved can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing the gist of the present invention.

FIG. 2 is a block diagram showing a configuration of a rolling mill driving electric motor control device according to an embodiment of the present invention.

FIG. 3 is a graph showing the effect of the above embodiment (switch SW
(When off)

FIG. 4 is a graph showing the effect of the embodiment (switch SW
(When on)

FIG. 5 is a graph showing the relationship between the rolling speed deviation amount and the rolled product sheet thickness deviation amount.

[Explanation of symbols]

 10 ... Rolling condition measuring device 12, 12a ... Rolling torque calculation device 14 ... Command value 14a ... Speed command 16 ... Feedback value 20, 20a ... Motor power control device 22 ... Speed compensator 24 ... Torque adjuster 26 ... Voltage adjuster 30 Model calculation computer 40 Rolling roll 42 Backup roll 44 Electric motor 46 Pulse generators 50a and 50b Plate thickness gauges 52a and 52b Tension meter 54 Rolling load meter

Claims (1)

[Claims] 1. A rolling mill driving electric motor control device for controlling the driving force of a rolling material when rolling the material to be rolled by opposing rolling rolls driven by an electric motor. A rolling mill driving electric motor control device comprising: a rolling torque calculation device for calculating a rolling torque G; and an electric motor power control device for controlling the driving force of the electric motor according to at least the rolling torque G.