JP6277903B2 - Finishing and rolling equipment for wire or bar - Google Patents

Description

  The present invention relates to a finish rolling apparatus for wire rods or steel bars.

  Conventionally, a block mill applied to a finish rolling process of a wire rod and bar rolling line is known. The block mill includes a plurality of stands having rolling rolls, and continuously rolls a material that is a wire or a steel bar in one direction.

  Generally, the block mill applied to the finish rolling process of a wire rod / steel rolling line is a common drive type in which a plurality of stands mechanically connected by gears are driven by a single electric motor (Patent Document 1). ).

  In recent years, each stand is individually driven by applying a small capacity, small space motor and a high-accuracy and high-response drive control device to each stand of the block mill in accordance with the technical progress of the motor and drive control device. A block mill having a mechanical configuration (hereinafter referred to as an individual drive type block mill) has been proposed (Patent Document 2).

  By adopting the individual drive type block mill, high precision, high response, high quality rolling by individual control of the motors arranged in each stand, which could not be realized in the machine configuration with the conventional common drive type block mill Is expected to be realized.

Japanese Patent Laid-Open No. 11-33611 Special table 2013-508172 gazette

  However, there is a problem in applying an individual drive type block mill. The problem of the individual drive type block mill will be described with reference to FIGS.

  FIG. 8 is a configuration diagram of a common drive type block mill. One electric motor 81 is connected to the gear box 82, and power is distributed to each stand 84 by the gear 83. Since all the stands are connected by gears, the stand housing 85 is integral.

  FIG. 9 is a block diagram of an individual drive type block mill. One motor 91 is connected to each stand 92, and the stands 92 are individually driven by the connection of the respective gears 93. The stand housing 94 is divided for each stand.

  In FIG. 8, a case where 10 stands (100 kW per stand) are driven by one 1000 kW electric motor is considered. In this case, the influence of the impact when the rolling roll of the stand bites the material is only 10% of 100 kW for a 1000 kW electric motor. In addition, since ten stands are integrated with a gear, and the moment of inertia in the rotating system is large, the amount of impact drop that causes the rolling speed to fall below the target speed is physically small.

  On the other hand, in FIG. 9, let us consider a case in which ten stands (100 kW per stand) are individually driven by ten 100 kW motors. In this case, the influence of impact when the rolling roll of the stand bites the material is 100% of 100 kW for a 100 kW electric motor. In addition, the moment of inertia in the rotating system is considerably smaller than that in the configuration shown in FIG. 8, which increases the amount of impact drop generated.

  For the above reasons, the impact drop characteristics are greatly different between the common drive type and the individual drive type. However, there is a problem that impact drop compensation for suppressing the amount of impact drop generation has not been sufficiently studied with respect to the individual drive type block mill applied to the finish rolling process of the wire rod and bar rolling line.

  For example, it is also conceivable to apply torque compensation by feedback control as used in a plate material rolling line to an individually driven block mill. However, in the finish rolling process of the wire rod / steel rolling line, the rolling speed is higher (for example, 100 m / sec) than the rolling of the plate material, and the space between the stands of the block mill is narrow. The rolling speed does not converge to the target speed by the time when the next stand is bitten, and impact drop due to biting of the next stand occurs before the speed reduction is recovered, so that sufficient speed control cannot be realized. Therefore, impact drop compensation by another method is necessary.

  The present invention has been made to solve the above-described problems, and in an individually driven block mill applied to a finish rolling process of a wire rod / steel rolling line, impact drop compensation with high accuracy and high response is provided. An object of the present invention is to provide a finish rolling apparatus for wire or steel bar that can realize the above.

In order to achieve the above-mentioned object, the first invention is a finish rolling apparatus for a wire rod or steel bar,
A plurality of stands from a first stand to an n-th stand (n ≧ 3 ) for continuously rolling a wire or a steel bar in one direction in a finish rolling process of a wire rod and bar rolling line, and the plurality of stands are provided respectively. A block mill having an electric motor for driving the stand according to an individually calculated electric motor torque instruction value;
A speed sensor provided on each of the plurality of stands and detecting a rolling speed of the stands;
Deceleration in the i-th stand based on the rolling speed detected by the speed sensor of the i-th stand when the tip of the material is caught in the i-th stand (1 ≦ i ≦ n−1) of the block mill. Deceleration torque calculating means for calculating torque;
The first stand calculated by the deceleration torque calculating means to a torque target value of the motor of the i + 1th stand set according to a speed target value of the stand when the tip of the material is bitten into the i + 1th stand. And feed-forward torque compensation means for calculating a motor torque instruction value to be given to the motor of the i + 1th stand reflecting each deceleration torque from the ith stand to the i-th stand (i ≧ 2) .

  According to a second aspect of the present invention, in the first aspect, the target speed value of the stand when the tip of the material is bitten into the i + 1th stand is based on the rolling speed detected by the speed sensor of the i + 1th stand. When it becomes smaller, it further comprises overcompensation suppression means for reducing the feedforward compensation torque according to the deceleration torque reflected in the torque target value.

  According to the present invention, the deceleration torque that affects the impact drop of the front stand is detected and stored, and the impact drop compensation is performed on the subsequent stand by the feed forward method. High response impact drop compensation can be realized. In addition, since the effect of impact drop compensation increases as going to the rear stage stand, finish rolling with high dimensional accuracy is possible. By applying the present invention to an individual drive type block mill, high accuracy, high response, and high quality were achieved by individual control of the motors arranged on each stand, which could not be realized due to the mechanical configuration of the common drive type block mill. Rolling can be realized.

In Embodiment 1 of this invention, it is a flowchart which shows the flow of the signal which implement | achieves the impact drop compensation of an individual drive type block mill. It is a block diagram of speed control for the conventional rolling stand. 3 is a timing chart of rolling using the speed control shown in FIG. FIG. 3 is a block diagram of a speed control system in which a feedforward compensation torque is added to the speed control system of FIG. 2. It is a timing chart of rolling by the system of Embodiment 1 of the present invention. FIG. 5 is a block diagram of a speed control system in which an overcompensation detection device is provided in the speed control system of FIG. 4. FIG. 2 is a flow diagram in which an adjustment device is incorporated in the signal flow diagram for realizing impact drop compensation by feedforward shown in FIG. 1. It is a block diagram of a common drive type block mill. It is a block diagram of an individual drive type block mill.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element which is common in each figure, and the overlapping description is abbreviate | omitted.

Embodiment 1 FIG.
[System Configuration of Embodiment 1]
FIG. 1 is a flowchart showing a signal flow for realizing impact drop compensation of an individual drive type block mill in Embodiment 1 of the present invention.

The finish rolling apparatus for a wire rod or steel bar shown in FIG. 1 includes an individually driven block mill 10 that continuously rolls a material that is a wire rod or steel bar in one direction in a finish rolling process of a wire rod / bar rolling line. The block mill 10 has n rolling stands (n ≧ 3 ). The 1st stand 11, the 2nd stand 12, the 3rd stand 13, and the nth stand 14 shown in Drawing 1 are each provided with a rolling roll.

  An electric motor for driving the rolling roll is connected to each of the first stand 11 to the n-th stand 14. Specifically, a first motor 21 is provided in the first stand 11, a second motor 22 is provided in the second stand 12, a third motor 23 is provided in the third stand, and an n-th motor 24 is provided in the n-th stand. It is connected. The arrangement of the first stand 11 to the n-th stand 14 and the first motor 21 to the n-th motor 24 is the same as, for example, the stand and the motor shown in FIG.

  Moreover, the finish rolling apparatus of a wire rod or steel bar is provided with the drive device connected to the 1st electric motor 21-the nth electric motor 24 separately. Specifically, the first motor 21 has a first drive device 31, the second motor 22 has a second drive device 32, the third motor 23 has a third drive device 33, and the nth motor 24 has a second drive device 32. An nth driving device 34 is connected. The electric motors 21 to 24 are individually controlled by the driving devices 31 to 34.

  Further, a speed sensor is attached to each of the first motor 21 to the n-th motor 24. Specifically, the first motor 21 has a first speed sensor 41, the second motor 22 has a second speed sensor 42, the third motor 23 has a third speed sensor 43, and the nth motor 24 has a second speed sensor 42. An nth speed sensor 44 is attached. The rolling speeds of the rolling rolls of the stands 11 to 14 can always be detected by the speed sensors 41 to 44.

  Further, the first stand 11 to the n-th stand 14 are provided with a biting detection device and a storage device, respectively. Specifically, a first biting detection device 51 and a first storage device 61 are provided in the first stand 11, and a second biting detection device 52 and a second storage device 62 are provided in the second stand 12 as a third stand. 13 is provided with a third biting detection device 53 and a third storage device 63, and the nth stand 14 is provided with an nth biting detection device 54. The biting of the material in each of the first stand 11 to the nth stand 14 is detected by the first biting detection device 51 to the nth biting device 54.

  The first storage device 61 to the third storage device 63 store the deceleration torque that is the torque fluctuation amount when the material is caught in the rolling rolls in the first stand 11 to the third stand 13. Preferably, the rolling speed is detected at a plurality of points from when the leading end of the material is bitten by the i-th stand (1 ≦ i ≦ n−1) to before being bitten by the i + 1th stand, and the detected rolling speed is detected. The deceleration torque is calculated every time, and the deceleration torque at each point is stored as time series data.

[Characteristic Control in Embodiment 1]
(Overview)
Next, an outline of characteristic control in the system according to the first embodiment of the present invention will be described. In the system according to the first embodiment of the present invention, first, the first storage device 61 stores the deceleration torque when the rolling roll of the first stand 11 bites the material. Then, when the second stand 12 is engaged, torque compensation by feedforward control is performed in which the first feedforward compensation torque obtained by inverting the sign of the deceleration torque of the first stand 11 is added to the torque target value of the second electric motor 22. I do.

  Similar to the first stand 11, the second storage device 62 stores the deceleration torque amount when the second stand 12 is bitten. When the third stand 13 is engaged, in addition to the second feedforward compensation torque obtained by reversing the sign of the deceleration torque of the second stand 12, the first feedforward compensation torque described above is used as the torque of the third motor 23. Torque compensation is performed by feedforward control that adds to the target value.

  In this way, the value obtained by reversing the sign of the deceleration torque of the front stand and the feed forward compensation torque up to the front stand are added to the torque target value of the electric motor when the rear stand is bitten by feed forward control. Perform torque compensation. This is repeated until the final stand (nth stand 14).

(Specific explanation)
More specifically, characteristic control in the system according to the first embodiment of the present invention will be described. First, the comparison target will be described with reference to FIGS.
FIG. 2 is a block diagram of speed control for a conventional rolling stand. The purpose of this control is to follow the target value of the rolling speed. The torque control is a so-called minor loop control in the speed control system, and the torque control system does not affect the outside of the speed control system which is the major loop control. In general, in the upper speed control system, the speed target value is controlled by interfering with each other's stand, but since the torque control of the motor is a minor loop control for speed following, it is independent at each stand. doing.

  FIG. 3 is a timing chart of rolling using the speed control shown in FIG. In the stand rotating at the target (set) speed, a speed drop (drop) occurs due to the impact when the rolling roll bites the material. The speed reduction is recovered with a certain amount of time by feedback speed control.

  However, as described above, in the finish rolling process of the wire rod and bar rolling line, the rolling speed is high (for example, 100 m / sec) and the distance between the stands of the block mill is short compared to the rolling of the plate. There is. Therefore, the feedback control has a problem that, as shown in FIG. 3, an impact drop due to biting of the next stand occurs before the speed drop due to the impact drop is recovered, and sufficient speed control cannot be realized. .

  In the system according to the first embodiment of the present invention, in order to solve this problem, the speed reduction at the time of biting each stand of the individually driven block mill is reduced by the above-described torque compensation by the feedforward control. This will be described more specifically with reference to FIGS.

  4 is a block diagram of a speed control system in which a feedforward compensation torque is added to the speed control system of FIG. As described above, the present invention is realized by calculating the feedforward torque compensation amount from the previous stand response results and adding the torque compensation to the conventional speed control system. Therefore, unlike the minor loop control of the torque to be compared, aggressive torque control is required. Further, as shown in FIG. 1, the result of the front stand is directly used for the torque control of the rear stand, and therefore, the torque control of the electric motor directly interferes with the rear stand unlike the comparison target.

FIG. 4 shows a block diagram of the speed control system of the i-th stand (i ≧ 2). Here, the second stand 12 will be described as an example. The speed target value N _ref shown in FIG. 4 is output from a higher-level PLC (Programmable Logic Controller) connected to the second drive device 32. The speed control device 71 and the motor torque control device 72 of FIG. 4 are included in the second drive device 32 of the second stand 12. Speed control device 71 inputs the speed target value _{N ref,} calculates a torque target value _{T ref} of the second electric motor 22 when biting wood. The motor torque control device 72 as the feedforward torque compensation means inputs the torque target value _Tref and the feedforward compensation torque _Tcomp calculated at the first stand (i-1th stand), and the motor torque instruction. Calculate the value. The second electric motor 22, the second driving the rolling rolls of the stand 12 in the electric motor torque T _m based on the motor torque command value. The rolling speed N of the stand is fed back to the speed controller 71, and the deviation from the speed target value N _ref is added to the next speed target value. The speed target value N _ref is sequentially updated based on the rolling conditions not only when the material is caught but also after the material is caught.

FIG. 5 is a timing chart of rolling by the system according to the first embodiment of the present invention.
The number of stands is n. The rolling speed of the i-th stand is N _i (rpm), the motor torque is T _{m (i)} (Nm), the acceleration / deceleration torque is T _{acc (i)} (Nm), and the rolling torque is T _{l (i)} (Nm). (I = 1 to n).

The relationship among the motor torque T _{m (i)} , acceleration / deceleration torque T _{acc (i)} , and rolling torque T _{l (i} ) is shown in Equation (1). In this description, since the speed reduction due to friction is ignored, the torque before biting is all zero.

The motor torque T _{m (i)} is controlled by the drive device and can be obtained as a numerical value. In order to directly measure the rolling torque T _{l (i)} , a dedicated sensor is required. In addition, it is generally difficult to directly measure the finish rolling torque of wire rods and steel bars. The rolling torque _{Tl (i)} cannot be measured. Deceleration torque _{T acc (i),} since the numerical differentiation of rolling speed _{N i} which can be detected by the speed sensor, to be known rotation system moment of inertia _J i (kgm ^2), can be calculated using equation (2) It is.

  The impact drop characteristic of the first stand does not have the feed-forward element of the previous stand, so that a large impact drop occurs without changing from the case of no control. The speed reduction is recovered by the action of the speed control system, and the motor torque during rolling finally settles to a constant rolling torque.

Speed reduction due to impact means that torque in the deceleration direction is generated in a rotating system composed of an electric motor and a stand. Here, from the time biting at first stand before biting at the second stand, the negative acceleration and deceleration torque is a decelerating torque component is defined as T _dec1, formula (2) of the T _dec1 using Store time-series data.

Then, feed forward torque compensation is _performed by adding a feed forward compensation torque T _comp2 obtained by reversing the sign of T _dec1 , which is a deceleration torque amount at the time of biting the front stand, to the target torque value at the time of biting at the second stand. Do. Preferably, the feedforward compensation torque based on the time-series data at each time point between the first and second stands is sequentially added in correspondence with the torque target value at each time point between the second and third stands. This feedforward torque compensation is effective from the time of biting in the second stand until before biting in the third stand. The feedforward compensation torque T _comp2 of the second stand is expressed by the following equation (3).

Since T _comp2 is added by the motor torque control device 72, the relationship between the torques of the second stand is expressed by the following equation (4).

By adopting such feedforward control, unlike the feedback control, the feedforward compensation torque T _comp2 causes the motor to output a torque that takes into account the impact drop from the moment of biting. Speed reduction can be reduced.

Third stand feedforward compensation torque T _comp3 is the time-series data obtained by pre-inverting the sign of T _dec2 a decelerating torque component of the stand, it is assumed that the sum of the feedforward compensation torque T _comp2 before stand still (Formula (5)).

  Similar to the second stand, the relationship between the torques of the third stand is expressed by the following equation (6).

  Expressions (7) and (8) are obtained by extending the feedforward torque compensation to the final stand according to Expressions (5) and (6). The feed forward torque compensation is effective from the biting of the i-th stand to the biting of the (i + 1) -th stand (i = 3 to n). The last stand disables control after the timer.

  The feedforward torque compensation shown in FIG. 1 is realized by the equations (3), (4), (7), and (8).

Embodiment 2. FIG.
[Characteristic Control in Embodiment 2]
In the first embodiment described above, the amount of feedforward compensation torque is accumulated as going to the rear stage stand. Then, the accumulated feedforward compensation may output more motor torque than necessary at the rear stage stand. When overcompensation (overcompensation) occurs, it causes a decrease in dimensional accuracy and a change in tension between stands. Therefore, it is necessary to suppress the occurrence of overcompensation.

The characteristic control of Embodiment 2 of the present invention will be described with reference to FIG. FIG. 6 is a block diagram of a speed control system in which an overcompensation detection device is provided in the speed control system of FIG. The overcompensation control device 73 serving as overcompensation suppression means compares the speed target value N _ref with the rolling speed N and determines that overcompensation occurs when N _ref <N. In the case of overcompensation, the feedforward compensation torque T _comp is reduced. For example, a value obtained by multiplying the feedforward compensation torque by a coefficient α (0 ≦ α <1) is set as a new feedforward compensation torque. The reduced feedforward compensation torque is input to the motor torque control device 72.

  Thus, by providing the overcompensation control device 73, the occurrence of overcompensation can be suppressed.

Embodiment 3 FIG.
[Characteristic Control in Embodiment 3]
In the first embodiment described above, torque compensation is simply performed for the deceleration torque due to the impact drop. However, in practice, a delay in torque control and an adjustment term for each stand are necessary.

  The characteristic control of the third embodiment of the present invention will be described with reference to FIG. FIG. 7 is a flow diagram in which an adjusting device is incorporated in the signal flow diagram for realizing the impact drop compensation by feedforward shown in FIG. As shown in FIG. 7, by providing the adjusting device 74 in each part, it is possible to adjust the control start timing and the characteristics of each stand.

10 block mill 11-14 1st stand, 2nd stand, 3rd stand, nth stand 21-24 1st motor, 2nd motor, 3rd motor, nth motor 31-34 1st drive device, 2nd drive Device, third driving device, n-th driving device 41-44 first speed sensor, second speed sensor, third speed sensor, n-th speed sensor 51-54 first biting detection device, second biting detection device, Third biting detection device, nth biting detection device 61-63 First memory device, second memory device, third memory device 71 Speed control device 72 Motor torque control device 73 Overcompensation control device 74 Adjustment devices 81, 91 Electric motor 82 Gear box 83, 93 Gear 84, 92 Stand 85, 94 Stand housing

Claims (2)

A plurality of stands from a first stand to an n-th stand (n ≧ 3 ) for continuously rolling a wire or a steel bar in one direction in a finish rolling process of a wire rod and bar rolling line, and the plurality of stands are provided respectively. A block mill having an electric motor for driving the stand according to an individually calculated electric motor torque instruction value;
A speed sensor provided on each of the plurality of stands and detecting a rolling speed of the stands;
Deceleration in the i-th stand based on the rolling speed detected by the speed sensor of the i-th stand when the tip of the material is caught in the i-th stand (1 ≦ i ≦ n−1) of the block mill. Deceleration torque calculating means for calculating torque;
The first stand calculated by the deceleration torque calculating means to a torque target value of the motor of the i + 1th stand set according to a speed target value of the stand when the tip of the material is bitten into the i + 1th stand. Feedforward torque compensation means for calculating a motor torque instruction value to be applied to the motor of the i + 1th stand reflecting each deceleration torque from the ith stand to ith stand (i ≧ 2) ,
A finish rolling apparatus for wire or steel bar, comprising: This is reflected in the torque target value when the speed target value of the stand when the tip of the material is bitten by the i + 1th stand becomes smaller than the rolling speed detected by the speed sensor of the i + 1th stand. Overcompensation suppression means for reducing feedforward compensation torque according to the deceleration torque
The finish rolling apparatus for wire or bar according to claim 1, further comprising:

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