JP2012135777A - Plate thickness control method and plate thickness control device for rolling mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable highly accurate plate thickness control.SOLUTION: In this plate thickness control method for a rolling mill, plate thickness of a rolled material W is measured, a roll clearance ΔS of work rolls rolling the rolled material W is calculated based in the measured plate thickness, and a command signal corresponding to the calculated roll clearance ΔS is output to a rolling reduction device so as to control the plate thickness of the rolled material W. A deviation of the plate thickness of the rolled material W is resolved into a frequency component, and a phase delay is calculated with respect to each frequency component. Based on the calculated phase delay, delay time with respect to each frequency is determined. Based on the delay time determined with respect to each frequency, total delay time is determined. Based on the calculated total delay time, timing of the command signal to be output to the rolling reduction device is corrected.

Description

  The present invention relates to a thickness control method and apparatus for a rolling mill.

As is well known, when cold rolling a rolled material such as stainless steel, titanium, special steel, copper, etc., a “cluster type multi-stage rolling mill” in which a group of rolls supporting a work roll expands in a fan shape like a bunch of straw ( Cluster rolling mills ”are generally used.
When rolling the rolled material in the cluster rolling mill, first, the sheet thickness of the rolled material is measured, the roll gap is calculated based on the measured sheet thickness, and the roll gap is controlled by a reduction device. The thickness is controlled.

  As shown in FIG. 5, the roll gap in the cluster rolling mill is output from the sheet thickness control device to the reduction device by a command signal for adjusting the roll clearance to the servo amplifier of the reduction device, and the servo valve is turned on via the servo amplifier. move. The servo valve operates in response to a command to move the hydraulic cylinder, and adjusts the roll gap by moving a wedge (wedge means) for adjusting the roll gap by expansion and contraction of the hydraulic cylinder.

In such a cluster rolling mill, even if a command signal is output from the plate thickness control device to the reduction device, there is a problem that it is difficult to control the plate thickness properly because servo valves, hydraulic cylinders, etc. have delay elements. .
In view of such a problem, there is a technique in which a command signal is compensated (corrected) in advance in consideration of a delay element such as a servo valve (Patent Document 1).

  In Patent Document 1, the entry side thickness deviation is sampled at a predetermined sampling period, and the sheet thickness control output corresponding to the entry side thickness deviation sampled at an arbitrary sampling time is controlled from the time when the rolling material sampling position arrives under the work roll. I try to advance by the time delay of the system.

JP-A-3-254309

  In Patent Document 1, the thickness deviation detected when calculating the time delay of the control system is used, but the thickness deviation for calculating the time delay is a fixed value (value when measured). Therefore, when the time delay is calculated using a fixed value, the accurate time delay cannot be obtained, and even if the command signal is corrected using this technique, the accuracy of the plate thickness may be reduced. In particular, when the plate thickness deviation fluctuates greatly, the actual situation is that it is difficult to control the plate thickness appropriately.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a sheet thickness control method and apparatus for a rolling mill that can perform highly accurate sheet thickness control.

In order to achieve the above-mentioned object, the following technical measures were taken.
The sheet thickness control method of the rolling mill of the present invention measures the sheet thickness of the rolled material, calculates the roll gap ΔS of the work roll that rolls the rolled material based on the measured sheet thickness, and calculates the calculated roll gap ΔS. A rolling plate thickness control method for controlling the thickness of the rolled material by outputting a corresponding command signal to a reduction device, wherein the deviation of the thickness of the rolled material is decomposed into frequency components, And calculating a delay time for each frequency based on the calculated phase delay, calculating an overall delay time based on the calculated delay time for each frequency, and based on the calculated overall delay time. This is to correct the timing of the command signal output to the reduction device.

It is preferable to advance the timing of the command signal output to the reduction device by the total delay time.
It is preferable that the number of sampling corrections is obtained by Equation (1) using the overall delay time, the rolling speed of the rolled material, and the sampling length of the rolled material, and the timing of the command signal is advanced by this number of sampling corrections.

  A sheet thickness control apparatus for a rolling mill according to the present invention is provided in a rolling mill including a sheet thickness measuring instrument for measuring a sheet thickness of a rolled material, and a reduction device for changing a roll gap ΔS of a work roll, and A plate thickness control device that outputs a command signal corresponding to a roll gap ΔS to a reduction device, the frequency resolution means for decomposing the thickness deviation of the rolled material into frequency components, and calculating the phase lag for each frequency component And a delay time calculating means for obtaining a delay time for each frequency based on the calculated phase delay, an overall delay calculating means for calculating an overall delay time based on the delay time obtained for each frequency, and the calculated overall And a timing correction means for correcting the timing of the command signal output to the reduction device based on the delay time.

Preferably, the timing correction means advances the timing of the command signal output to the reduction device by the overall delay time.
The timing correction means obtains the number of times of sampling correction by the equation (1) using the overall delay time, the rolling speed of the rolled material, and the sampling length of the rolled material, and advances the timing of the command signal by this number of times of sampling correction. Is preferred.

  According to the present invention, highly accurate plate thickness control can be performed.

It is the schematic of the rolling apparatus provided with the cluster rolling mill. It is the figure which showed the plate | board thickness deviation of the entrance side. FIG. 6 is a relationship diagram between a frequency f _n and a phase delay θ _n in a first-order lag system. It is a flowchart which rolls a rolling material, controlling by a plate | board thickness control apparatus. It is the schematic of the reduction apparatus with which the cluster rolling mill was equipped.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, a rolling device 1 cold-rolls a rolled material W such as stainless steel, titanium, special steel, and copper, and is a cluster type rolling mill (hereinafter referred to as a cluster) that rolls the rolled material W. 2), an unwinding reel 3 for unwinding the rolled material W, and a take-up reel 4 for winding the rolled material W.

The cluster rolling mill 2 is configured by combining a plurality of upper and lower pairs of work rolls 5, intermediate rolls 7, and backup rolls 8. A pair of upper and lower work rolls 5, an intermediate roll 7, and a backup roll 8 are arranged like a cocoon in side view.
Specifically, in the cluster rolling mill 2 of this embodiment, four intermediate rolls 7 (two vertically) are arranged around a pair of upper and lower work rolls, and six backup rolls 8 are arranged around the intermediate roll 7. (3 pieces on the top and bottom) are arranged. In addition, the number of each roll is not limited to this embodiment. Moreover, the rolling mill 2 is not limited to a cluster type, and may be a normal multi-stage rolling mill.

A thickness measuring device 10 for measuring the thickness of the rolled material W is provided on the entry side or the exit side of the cluster rolling mill 2. The cluster rolling machine 2 includes a reduction device 11 that changes the roll gap ΔS according to the plate thickness measured by the plate thickness measuring instrument 10, a calculation that changes the roll gap ΔS, and the like, and a plate that controls the reduction device 11. And a thickness control device 12. The roll gap ΔS is
Using the plate thickness deviation ΔH measured by the plate thickness measuring instrument 10 and the like, it is obtained by the equation (a).

  As shown in FIG. 5, the reduction device 11 includes a wedge 15 that moves each backup roll 8 by movement to change the roll gap ΔS, a hydraulic cylinder 16 that moves the wedge 15, and a servo valve that operates the hydraulic cylinder 16. 17. A command signal from the plate thickness controller 12 is input to the servo valve 17 via a servo amplifier 18, and the hydraulic cylinder 16 is moved by the operation of the servo valve 17.

  The plate thickness control device 12 calculates a roll gap ΔS based on the plate thickness measured by the plate thickness measuring instrument 10 and outputs a command signal corresponding to the roll gap ΔS to the reduction device 11. In the present invention, as described above, a control delay is caused by a delay element such as the servo valve 17 or the hydraulic cylinder 16, so that an appropriate plate thickness can be obtained by correcting the output timing of the command signal (sometimes referred to as output timing). Control is going to be done.

Hereinafter, a sheet thickness control method and a sheet thickness control apparatus for a rolling mill according to the present invention will be described in detail.
The plate thickness control device 12 includes a frequency resolving unit 20, a delay time calculating unit 21, an overall delay calculating unit 22, and a timing correcting unit 23.
The frequency resolving means 20 is for resolving the plate thickness deviation ΔH calculated based on the plate thickness measured by the plate thickness measuring instrument 10 into frequency components.

  FIG. 2 shows an example in which the inlet side plate thickness is measured by the plate thickness measuring instrument 10 and the inlet side plate thickness deviation ΔH is obtained by this measurement. The frequency decomposing means 20 decomposes the plate thickness deviation ΔH as shown in FIG. 2 into each frequency as shown in Expression (2) by a frequency analyzer.

The delay time calculation means 21 calculates a phase delay for each frequency component decomposed by the frequency decomposition means 20. Specifically, the relationship between each frequency f _n and the phase delay θ _n in the delay element of the reduction device 11 is obtained in advance as shown in FIG. 3 based on past rolling results, computer simulation, etc., and the delay time calculating means 21 calculates a phase lag for each frequency component from each frequency f _n as shown in FIG. 3 and the phase lag θ _n in the control system. Then, the delay time calculating means 21 calculates the delay time for each frequency based on the calculated phase delay, that is, calculates the delay time for each frequency by the equation (3).

  The total delay calculating means 22 calculates the total delay time based on the delay time determined for each frequency, that is, the total delay time is calculated by the equation (4).

  The timing correction unit 23 corrects the timing of the command signal output to the reduction device based on the total delay time calculated by the total delay calculation unit 22. The timing correction means 23 outputs the command signal timing earlier by the entire delay time, thereby making the plate thickness control by the delay element appropriate (control with the delay element corrected). Specifically, the processing is performed as follows.

First, the sampling length in the longitudinal direction of the rolled material W (control unit length, that is, the length of the cut plate) is Ls, and the length from the plate thickness measuring instrument 10 directly below the work roll 5 (rolling position) is Assuming L, the sampling number K ₀ from the measurement point measured by the plate thickness measuring instrument 10 to the reduction position is K ₀ = L / Ls. Here, considering the sampling signal output for each sampling length (control unit length) Ls, if there is no delay element, the number K counted by the sampling signal is the sampling number K ₀ (K = K ₀ ). When they are the same, the command signal may be output to the reduction device.

However, since there is a delay element in the reduction device as described above, it is necessary to advance the output of the command signal by the delay, that is, the entire delay time. In the present invention, the number of sampling corrections ΔK ₀ is obtained by Equation (1) using the overall delay time, the rolling speed of the rolled material W, and the sampling length Ls of the rolled material W.

In obtaining the sampling correction count ΔK ₀ , that is, the sampling correction count, the rolling speed changes until the rolled material W reaches the work roll 5 from the plate thickness measuring instrument 10 as shown in the equation (1). Since there is a possibility, the rolling speed is also taken into consideration.
The timing correction means 23 outputs a command signal that has been output to the reduction device 10 when the count of sampling in the past is K, when K ₀ −ΔK ₀ . That is, the timing correction means 23 obtains the sampling correction number ΔK ₀ by the equation (1), and advances the timing of the command signal by this sampling correction number (shift number) ΔK ₀ .

FIG. 4 shows a flow chart of rolling the rolled material W while performing control by the plate thickness control device 12.
As shown in FIG. 4, first, in the first step, the plate thickness measuring instrument 10 measures the plate thickness on the entry side, and the plate thickness deviation ΔH 1 is read. Next, in the second step, as shown in the equation (2), the frequency decomposition means 20 decomposes the entry side thickness deviation ΔH for each frequency.

In the third step, the delay time calculation means 21 obtains the phase delay corresponding to each frequency using the relationship diagram between each frequency f _n and the phase delay θ _n as shown in FIG. In the fourth step, the delay time calculation means 21 converts the phase delay θ _n for each frequency f _n into a time delay using equation (3).
In the fifth step, the overall delay calculation means 22 calculates the overall delay time based on the delay time obtained for each frequency using Equation (4). In the sixth step, the number of sampling corrections ΔK ₀ is obtained by equation (1) using the overall delay time and the like, and the command signal is output to the reduction device by advancing the timing of the command signal by the number of sampling corrections ΔK ₀ . In the seventh step, it is determined whether or not to continue the above processing (calculation). When the plate thickness control is continued, the process returns to the first step, and ends when the process is stopped.

  According to the present invention as described above, the deviation of the thickness of the rolled material W is decomposed into frequency components, the phase delay is calculated for each frequency component, and the delay time for each frequency is calculated based on the calculated phase delay. The total delay time is calculated based on the obtained delay time for each frequency, and the timing of the command signal output to the reduction device is corrected based on the calculated total delay time. For this reason, it is possible to output the command signal by reliably reflecting the characteristics of the delay element for each frequency inherent in the reduction device 11, and thereby it is possible to control the plate thickness with high accuracy.

  It should be noted that matters not explicitly disclosed in the embodiment disclosed this time, such as operating conditions and operating conditions, various parameters, dimensions, weights, volumes, and the like of a component, deviate from the range normally practiced by those skilled in the art. However, matters that can be easily assumed by those skilled in the art are employed.

DESCRIPTION OF SYMBOLS 1 Rolling apparatus 2 Cluster rolling mill 3 Unwinding reel 4 Take-up reel 5 Work roll 6 2nd intermediate roll 7 Intermediate roll 8 Backup roll 10 Plate thickness measuring instrument 11 Rolling device 12 Plate thickness control device 15 Wedge 16 Hydraulic cylinder 17 Servo valve 18 Servo amplifier 20 Frequency resolving means 21 Delay time calculating means 22 Overall delay calculating means 23 Timing correcting means ΔH Incoming plate thickness deviation W Rolled material

Claims (6)

The thickness of the rolled material is measured, the roll clearance ΔS of the work roll that rolls the rolled material is calculated based on the measured thickness, and the command signal corresponding to the calculated roll clearance ΔS is output to the reduction device A rolling mill thickness control method for controlling the thickness of a rolled material,
Decomposing the thickness deviation of the rolled material into frequency components,
While calculating the phase delay for each frequency component, and determining the delay time for each frequency based on the calculated phase delay,
Calculate the overall delay time based on the delay time obtained for each frequency,
A sheet thickness control method for a rolling mill, characterized in that the timing of a command signal output to a reduction device is corrected based on the calculated overall delay time.   The sheet thickness control method for a rolling mill according to claim 1, wherein the timing of the command signal output to the reduction device is advanced by the entire delay time. 2. The number of sampling corrections is obtained by equation (1) using the overall delay time, the rolling speed of the rolled material, and the sampling length of the rolled material, and the timing of the command signal is advanced by the number of sampling corrections. The sheet thickness control method of the rolling mill as described in 2.

Provided in a rolling mill having a thickness measuring device for measuring the thickness of the rolled material and a reduction device for changing the roll gap ΔS of the work roll, and a command signal corresponding to the roll clearance ΔS is sent to the reduction device. A plate thickness control device for outputting,
Frequency resolving means for decomposing the deviation of the thickness of the rolled material into frequency components;
A delay time calculating means for calculating a phase delay for each frequency component and obtaining a delay time for each frequency based on the calculated phase delay;
An overall delay calculating means for calculating an overall delay time based on the delay time obtained for each frequency;
Timing correction means for correcting the timing of the command signal output to the reduction device based on the calculated overall delay time;
A sheet thickness control device for a rolling mill.   The sheet thickness control device for a rolling mill according to claim 4, wherein the timing correction means advances the timing of the command signal output to the reduction device by the overall delay time. The timing correction means obtains the number of times of sampling correction by the equation (1) using the overall delay time, the rolling speed of the rolled material, and the sampling length of the rolled material, and advances the timing of the command signal by this number of times of sampling correction. The thickness control apparatus of the rolling mill of Claim 4 characterized by these.

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