JP3055764B2 - Tension control method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for rolling a coiled material to be unwound from a rewinding machine by a rolling mill and winding the coiled material again into a coil by a winder. The present invention relates to a tension control method and apparatus for controlling the rotation speed of a drive motor of the rewinding machine and the winding machine such that the tension is detected by a detection device and the tension coincides with a predetermined tension command value. Suitable for use in rolling of stainless steel plates by a mill, even when the tension fluctuation is large, such as at the start of reel winding, or even when the coil outer diameter changes, an optimal control gain is obtained to suppress disturbance in the tension fluctuation. The present invention relates to a tension control method and apparatus capable of controlling the tension.

[0002]

2. Description of the Related Art As shown in FIG. 1, a stainless steel sheet is rolled by a reverse mill 20 having a cluster structure such as a Sendzimir mill having a small-diameter work roll, which is widely used for cold rolling of a stainless steel sheet. When the strip 10 is wound, a step is formed in the winding start portion due to the thickness of the mother plate of the strip 10, and as the reel 22 rotates, the step causes periodic tension fluctuation. In FIG. 1, reference numeral 24 denotes a deflector roll.

In order to eliminate the tension fluctuation caused by the reel eccentricity, Japanese Patent Application Laid-Open No. Sho 61-56728 detects the tension of the strip of the entrance reel or the exit reel, finds the amount of eccentricity of the mandrel of the reel, and uses this amount as a basis. Describes that a tension correction signal for canceling a tension variation due to reel eccentricity is input to a motor control device for an entrance reel or an exit reel to reduce tension variation due to reel eccentricity.

In Japanese Patent Application Laid-Open No. 62-93026, attention is paid to the fact that tension fluctuations due to reel eccentricity are synchronized with the rotation angle of the reel, and the amount of fluctuation in tension is predicted and calculated from the rotation angle. It is described that a change in the tension is suppressed by changing the tension command value so as to cancel this.

Japanese Patent Application Laid-Open No. 63-26215 discloses that a tension signal having a periodicity depending on one rotation of a reel is determined based on a tension signal and a reel rotation position detection signal, and the periodic fluctuation depending on one rotation of the reel is determined. It is described that, depending on the amount, a tension correction signal for canceling this variation is supplied to the input side and output side reel motors.

Japanese Unexamined Patent Publication (Kokai) No. 64-71522 discloses that a tension command value is corrected when the rotation angle of an unwinder type or a winder reaches a rotation angle range in which a tension variation occurs. It describes detecting a coil diameter of a band-shaped material applied to a winding machine or a winder, and correcting a rotation angle range and a tension correction amount according to the correction in accordance with the detected coil diameter.

[0007]

However, in order to suppress the periodic tension fluctuation due to the step at the reel winding start portion of the strip, if the number of rotations for sampling the tension waveform is constant, the rotation speed at the start of reel winding is reduced. As described above, when the tension fluctuation is large, there is a problem that the control cannot be performed in time.

FIG. 2 shows a conventional rotation speed constant sampling method in which a tension waveform is sampled and averaged for each constant rotation speed, phase correction is performed, a current command is issued as a control gain, and the rotation speed of the reel is changed. It is a tension fluctuation chart at the time of rolling using a control method. As is clear from the figure, the large tension fluctuation at the start of reel winding of the strip is not completely suppressed.

Further, in the method of keeping the gain that suppresses the tension fluctuation due to the step of the reel winding portion of the strip constant, the fluctuation cannot be suppressed when the coil outer diameter becomes small, that is, when the tension fluctuation becomes large. Conversely, when the coil outer diameter becomes large, that is, when the tension fluctuation becomes small, there is a problem that the gain is too large and the control may be adversely affected.

FIG. 3 shows a tension variation chart according to a conventional method in which the gain for suppressing the tension variation is constant regardless of the coil outer diameter. As is clear from the figure, while the tension fluctuation is suppressed at the coil middle part,
It can be seen that the tension fluctuation is large at the coil winding start portion and the payout portion.

As described above, if the tension fluctuates due to the eccentricity of the reel, the sheet thickness accuracy is reduced. Conventionally, it is necessary to reduce the rolling speed in the finishing pass to improve the sheet thickness accuracy, and the rolling efficiency is also improved. There was a problem that it was not possible.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and it is a first object of the present invention to perform accurate control even when the tension fluctuation is large, such as at the start of reel winding.

A second object of the present invention is to obtain an optimum gain irrespective of a change in coil outer diameter.

[0014]

SUMMARY OF THE INVENTION According to the present invention, there is provided a coiled material to be unwound from a rewinding machine, which is rolled by a rolling mill and then wound again into a coil by a winding machine. Is detected by a tension detecting device, and the rotational speeds of the drive motors of the rewinding device and the winding device are controlled so that the tension matches a predetermined tension command value. The rotation angle of the reel of the machine is detected, and the tension waveform is sampled to obtain an average tension waveform for each predetermined number of rotations. In suppressing the tension fluctuation synchronized with the rotation, the sampling rotation speed of the tension waveform, from the start of winding the material to be rolled to the winding machine until reaching a predetermined number of turns, gradually increases according to a predetermined pattern, From rewinding machine Until completion rewinding the material to be rolled is unwound from a predetermined number of turns, so as to gradually decrease in accordance with a predetermined pattern is obtained by solving the first problem.

Further, the second problem is solved by detecting the outer diameters of the coils of the winding machine and the rewinding machine and correcting the control gain based on the outer diameters of the coils.

Further, according to the present invention, in a similar tension control device, a rotation angle detecting means for detecting a rotation angle of a reel of the winding machine and the rewinding machine, and from the start of winding of the rolled material to the winding machine. Until the predetermined number of windings is reached, the number gradually increases in accordance with a predetermined pattern. A sampling means for sampling a tension waveform detected by the tension detecting device for each rotation speed; an average tension waveform obtained by averaging the tension waveforms sampled by the sampling means to obtain an average tension waveform; The first problem has been solved by providing control means for correcting the command value.

The present invention further comprises means for detecting the outer diameters of the coils of the winding machine and the rewinding machine, and the control gain is corrected by the outer diameters of the coils, thereby obtaining the second control signal.
It is a solution to the above problem.

The present invention reduces the number of sampling rotations of the tension waveform when the tension fluctuation is large, such as at the beginning of winding of the coil or the payout portion (the sampling frequency is increased,
The sampling cycle is shortened), and the timing of the control output is advanced so that the tension fluctuation can be reliably suppressed. Specifically, at the start of reel winding of the strip or at the time of payout, the sampling rotation speed is reduced to advance the timing of the control output, while the sampling rotation speed is increased in the middle portion where the coil diameters of the left and right reels are almost equal, and the control gain is increased. Prevent saturation.

When the inventors investigated the relationship between the variation in tension and the change in coil outer diameter by the conventional control method in which the gain was kept constant irrespective of the coil outer diameter, as shown in FIG. It was found that the tension fluctuation became smaller as the size became larger. Therefore, in the present invention, the control gain is changed according to the change in the coil outer diameter as necessary, so that an optimum control gain is obtained. Specifically, when the coil outer diameter is small and the tension fluctuation is large, as shown in FIG. 5, the control gain is increased to further suppress the tension fluctuation. On the other hand, when the coil outer diameter is large and the tension fluctuation is small, In the Japanese Patent Application Laid-Open No. H11-157, the control gain is reduced to suppress the disturbance of the tension fluctuation due to the extra control gain.

[0020]

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

FIG. 6 is a block diagram showing the overall configuration of a rolling mill to which the present invention is applied. 10 tension is detected. In addition, a reel rotation angle detector 32 that detects that the reel has reached a certain rotation angle is provided on the entrance and exit reels 22 that can be a rewinding machine or a winding machine depending on the rolling direction. The tension correction device 40 samples the tension waveform input from the tension meter 30 in accordance with the rotation angle of the reel 22 detected by the reel rotation angle detector 32 to obtain an average tension waveform for each predetermined rotation speed. By using the tension waveform as a control gain and correcting the command value given to the motor control device 28 of the reel drive motor 26, the tension fluctuation synchronized with the rotation of the reel 22 is suppressed.

In the tension compensator 34, as shown in detail in FIG. 7, the tension waveform input from the tension meter 30 is captured via a filter 42, and the angle sampling circuit 44 determines the angle of the mandrel of the reel 22. The tension fluctuation value at every 30 ° divided into 12 is taken in. Next, the difference from the set tension is obtained by the subtractor 46, and as shown in FIG. 8, the tension deviation for a predetermined number of rotations of the reel n (for example, 10) is stored in the memory 48. Next, the averaging circuit 50
To obtain an average value for n rotations, thereby obtaining a waveform to be used for control. In order to enhance the effect of feedforward control, the phase is shifted by a phase correction circuit 52 to give a reel angle and a phase difference. After the rotation angle is adjusted at 54 and multiplied by the control gain K at the amplifier 56, the result is added to the previous control output by the adder 58, passed through the limiter 60, and output to the motor controller 28.

In the first embodiment of the present invention,
As shown in FIG. 9, the reel rotation speed (referred to as sampling rotation speed) for obtaining the average of the tension deviation stored in the memory 48 is, as shown in FIG. During a period from the start of winding until the number of windings reaches a predetermined number, for example, n = 1 rotation to 1 according to a predetermined pattern.
From 0 to 10 rotations, the rolling material is gradually increased by 1 rotation. From the predetermined number of turns to the end of rewinding from the rewinding machine, according to a predetermined pattern, for example, from n = 10 rotations to 1 rotation, 1 rotation. The rotation is gradually reduced. In FIG. 9, reference numeral 62 denotes a sampling switch (SW) mainly having the functions of the angle sampling circuit 44 to the averaging circuit 50 of FIG. 7, and reference numeral 64 denotes a control which also has the functions of the phase correction circuit 52 to the rotation angle correction circuit 54. A reference numeral 66 denotes a tension adjuster (Automatic Tension Regurator); 68 denotes a current detector constituting a part of the motor control device 28 in FIG.
Is an adder, and 72 is a current regulator (Automa
tic Current Regurator), 74 is also a cycloconverter.

FIG. 11 is a diagram showing the timing of sampling the tension waveform and outputting the control gain. Since the output timing of the control gain at the time when the coil outer diameter is small and the tension variation is large is fast, the tension variation can be suppressed quickly.

FIG. 12 shows how the tension changes when the sampling rotation speed is changed as shown in FIG. 10 according to the first embodiment of the present invention. Compared to the conventional example shown in FIG.
It is clear that the tension fluctuation at the strip winding start portion is suppressed.

Next, a second embodiment of the present invention in which the control gain K of the amplifier 56 is corrected according to a change in the coil outer diameter will be described in detail.

The main configuration of the control circuit in the second embodiment is as shown in FIG. 13. Compared with the first embodiment, the coil outer diameter detector 76 and the control gain correction circuit 78 are provided.
Is different from that of the first embodiment in that the control gain K is changed according to the coil outer diameter D as shown in FIG. The other points are the same as those of the first embodiment, and the description is omitted.

FIG. 14 shows an example of the tension fluctuation in the second embodiment. Since the control gain K was changed in accordance with the coil outer diameter, compared to the example according to the conventional method shown in FIG.
The tension fluctuation can be suppressed at the coil winding start portion and at the payout portion as well as at the intermediate portion.

Although the coil outer diameter is detected by the coil outer diameter detector 76 in the second embodiment, a reel obtained by integrating the reel rotation angles detected by the reel rotation angle detector 32 is used. It is also possible to estimate the coil outer diameter from the rotation speed.

[0030]

As described above, according to the present invention,
Since the sampling rotation speed of the tension waveform is changed, it is possible to suppress a fluctuation in tension at the start of reel winding.

In particular, when the control gain is changed by changing the outer diameter of the coil, it is possible to further suppress the variation in tension between the winding start portion and the payout portion of the coil.

By suppressing the fluctuation of the tension in this way, it is possible to improve the thickness accuracy and to improve the quality. Furthermore, the rolling speed can be increased,
The rolling efficiency can also be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a tension reel showing causes of occurrence of reel eccentricity.

FIG. 2 is a diagram showing a tension fluctuation chart in a conventional control in which a sampling rotation speed is fixed.

FIG. 3 is a diagram showing a tension fluctuation chart in a conventional control in which a control gain is fixed irrespective of a coil outer diameter;

FIG. 4 is a diagram showing an example of a relationship between a coil outer diameter and a tension variation.

FIG. 5 is a diagram showing an example of a relationship between a coil outer diameter and a control gain in a second embodiment of the present invention.

FIG. 6 is a block diagram showing an overall configuration of a rolling facility to which the present invention is applied;

FIG. 7 is a circuit diagram showing a configuration of a reel eccentricity removal control portion of the tension correction device.

FIG. 8 is a diagram showing an example of a tension waveform;

FIG. 9 is a circuit diagram illustrating a main configuration of a control circuit according to the first embodiment of the present invention.

FIG. 10 is a diagram showing an example of a change state of the sampling rotation speed.

FIG. 11 is a diagram showing an example of the relationship between reel rotation and control output.

FIG. 12 is a diagram showing an example of a tension fluctuation chart.

FIG. 13 is a circuit diagram showing a main configuration of a control circuit according to a second embodiment of the present invention.

FIG. 14 is a diagram showing an example of a tension fluctuation chart.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Strip 20 ... Mill 22 ... Reel 26 ... Reel drive motor 28 ... Motor control device 30 ... Tensiometer 32 ... Reel rotation angle detector 40 ... Tension correction device 50 ... Averaging circuit n ... Sampling speed 56 ... Amplifier K ... Control gain 62 ... Sampling switch 64 ... Control unit 76 ... Coil outer diameter detector D ... Coil outer diameter 78 ... Control gain correction circuit

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-62-93026 (JP, A) JP-A-63-26215 (JP, A) JP-A-64-71522 (JP, A) (58) Field (Int. Cl. ⁷ , DB name) B21C 47/00

Claims (4)

(57) [Claims] A coiled material to be unwound from a rewinding machine is rolled by a rolling mill, and the tension of the material to be rolled when it is wound into a coil again by a winder is detected by a tension detector. In a tension control method for controlling a rotation speed of a drive motor of the unwinder and the winder so that the tension matches a predetermined tension command value, a rotation angle of a reel of the winder and the reel is detected. At the same time, the tension waveform is sampled to obtain an average tension waveform for each predetermined number of rotations, and the tension command value is corrected using the average tension waveform as a control gain, thereby suppressing a tension fluctuation synchronized with the rotation of the reel. In doing so, the sampling rotation speed of the tension waveform is gradually increased according to a predetermined pattern from the start of winding of the rolled material to the winding machine to the predetermined winding number, and the rolling material from the rewinding machine is increased. Rewind is prescribed Until the end of rewinding from the number of turns,
A tension control method characterized in that the tension is gradually reduced according to a predetermined pattern. 2. The tension control method according to claim 1, further comprising detecting the outer diameters of the coils of the winding machine and the rewinding machine, and correcting the control gain based on the outer diameters of the coils. 3. A coil-shaped material to be unwound from a rewinding machine is rolled by a rolling mill, and the tension of the material to be rolled when it is wound into a coil again by a winder is detected by a tension detecting device. A tension control device that controls a rotation speed of a drive motor of the rewinding device and the winding device so that the tension matches a predetermined tension command value, wherein a rotation angle of a reel of the winding device and a reel of the rewinding device is detected. From the start of winding of the rolled material to the winding machine until the predetermined number of turns is reached, the rotation angle is gradually increased according to a predetermined pattern, and the unwinding of the rolled material from the rewinding machine is performed at a predetermined angle. During the period from the number of windings to the end of rewinding, sampling means for sampling a tension waveform detected by the tension detecting device at every predetermined rotation number gradually decreasing according to a predetermined pattern; and a tension waveform sampled by the sampling means. To Leveling to determine the average tension waveform, tension control device characterized by and a control means for correcting the tension command value the average tension waveform as the control gain. 4. The apparatus according to claim 3 , further comprising means for detecting the outer diameters of the coils of the winding machine and the rewinding machine, wherein the control gain is corrected based on the outer diameters of the coils. Tension control device.