JPS61189811A - Control method of plate thickness - Google Patents

Abstract

PURPOSE:To control plate thickness of rolled plates accurately by dividing a thickness control signal into a high frequency component for tension control and a low frequency component for reduction position control and controlling a plate thickness using the above two components simultaneously for rolling metal plates and controlling a plate thickness by adjustment of both tension and reduction position. CONSTITUTION:A longitudinal plate thickness control signal (c) is calculated by adding an inlet side plate thickness deviation signal (a) which is the difference between a measured thickness by an inlet side thickness gage 6a of the mill 1 and the target value to an outlet side plate thickness deviation (b) signal measured an outlet side plate thickness gage 6b of the mill 1 by a plate thickness controller 7 for rolling of steel plates S by the rolling mill 1. That signal is divided into a high frequency component (d) for tension control of a steel plate between reels 2 and 3 and the mill 1 and a low frequency component (e) for reduction position control through a filter. The signal (d) is outputted to an inlet and outlet side tension controllers 4 and 5 and the signal (e) is outputted to a reduction position controller 13. Simultaneous adjustment of both a tension and pressing-down position controls makes a longitudinal plate thickness be equal to the target thickness quickly and accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of controlling plate thickness by simultaneously adjusting tension and rolling position.

[Prior art]

Generally, as a method of controlling the plate thickness by adjusting the tension and the position of reduction, a method is known in which the tension and the position of reduction are independently articulated, for example, as disclosed in JP-A-50-117660. In this case, plate thickness control by tension and plate thickness control by adjusting the rolling position are often treated equally, but in reality, the flatness, which is an important evaluation element of the product quality of rolled material, is improved, and Control based on tension adjustment, which has excellent responsiveness, is often required, but the range in which the tension can be adjusted is narrow when controlling the plate thickness by adjusting the tension, and the plate thickness will soon reach saturation. The problem was that it was not possible.

#i! Due to such a narrow tension adjustment range! To eliminate the problem of thickness control saturation, the tension is above saturation.

A method has been proposed in which when the lower limit value is exceeded and it becomes impossible to control the plate thickness by tension, a part of the plate thickness control amount is shared by adjusting the rolling position to eliminate the tension saturation state (Japanese Patent Application Laid-Open No. 5-1111).
2-40455).

[Problem that the invention seeks to solve]

By the way, in the above-mentioned method of controlling the plate thickness W by adjusting the tension, a part of it is assigned to the adjustment of the rolling reduction value Wl. Since the tension is returned to within the upper and lower saturation limits, the transient period between when the tension exceeds the upper and lower saturation limits and when the tension adjustment returns to within the upper and lower saturation limits by adjusting the reduction position. However, there is a problem in that it may become impossible to control the plate thickness by adjusting the tension.

In addition, the responsiveness of pressure adjustment is lower than that of tension adjustment.
There was also the problem that there was a large delay in control and it was difficult to accurately control the plate thickness.

The inventor conducted experiments and research on a method for simultaneously controlling plate thickness by adjusting the rolling position and tension, and as a result, the measured values of plate thickness obtained at the entrance and exit sides of the rolling mill were made to match the target value. Analyzing the plate thickness control signals calculated in this way, we find that a signal with a small amplitude but with a steep change (i.e., a signal with a high frequency component) and a signal with a large amplitude but with a gradual change (i.e., a signal with a low frequency component) In addition, when the plate thickness is controlled by adjusting the tension and the rolled down position, when the tension is adjusted, the plate thickness changes almost at the same time, but when the rolled down position is adjusted. In this case, only the tension before and after the rolling mill changes, but the outlet plate thickness does not change, and the plate thickness changes only after the constant tension control is activated, which returns the changed tension to its original value. Even when adjustment is made, tension adjustment is always involved in changes in plate thickness, and changes in plate thickness due to tension adjustment have a much faster response than changes in plate thickness due to adjustment of the rolling position.In other words, tension adjustment is It was found that adjustment of the rolling position is suitable for correcting high-frequency plate thickness deviations and low-frequency plate thickness deviations.

[Means for solving problems]

The present invention has been made based on the above-mentioned knowledge, and its purpose is to control the plate thickness deviation, in other words, to control the plate thickness by using the plate thickness control signal to control the plate thickness by adjusting the tension, and to use the high frequency component and the rolling position adjustment. We provide a plate thickness control method that achieves high control accuracy and high-quality rolled material by separating the low-frequency components from the low-frequency components passed through the plate thickness control and simultaneously controlling the plate thickness using each component. There is something to do.

The plate thickness control method according to the present invention measures the plate thickness of each part in the longitudinal direction of the rolled material at the entry side and/or exit side of the rolling mill, and based on these measured values, measures necessary to make the plate thickness match the target value. A plate thickness control signal for each part in the longitudinal direction of the rolled material is calculated, and the plate thickness control signal is separated into a rolling position correction signal and a tension correction signal that share plate thickness control, and rolling is performed based on these signals. It is characterized by simultaneous adjustment of position and tension.

〔principle〕

First, the principle of the method of the present invention will be explained based on FIGS. 1(A) to 1(E). Figures 1 (A) to (E) all show the time axis on the horizontal axis, and the difference between the measured value of the plate thickness and the target value obtained from the entrance side of the rolling mill, that is, the deviation of the thickness at the entrance side. Assume that a graph as shown in FIG. 1(A) is obtained for this case, and a graph as shown in FIG. Plate thickness control is performed by feedforward and feedback based on each of these graphs.
These plate thickness control signals are added to obtain plate thickness control signals for each portion of the rolled material in the longitudinal direction as shown in FIG. 1(c). So this board r! For example, use a filter (low-pass filter or bypass filter) to control the control signal, and set the upper limit frequency that can be controlled to follow the actual plate thickness change by adjusting the reduction position as the reference frequency, and use the control signal with a lower frequency than this as the reference frequency. Separately, a plate thickness control signal as shown in FIG. 1(d) is obtained, and this low frequency control signal is subtracted from the control signal shown in FIG. 1(c) to obtain a high frequency control signal as shown in FIG. 1(e). Obtain frequency control signals, respectively in Figure 1 (
The control signal shown in e) is output to the inlet and/or outlet tension (reel current) control device, and the low frequency control signal shown in Fig. 1 (d) is output to the reduction position control device. Simultaneously adjust the position and control the plate thickness.

With this type of control, the thickness deviation at high frequencies is controlled by adjusting the tension, and the thickness deviation at low frequencies is controlled by adjusting the roll position. As a result, the low responsiveness due to the reduction of the roll position has no effect on the thickness control. Accurate plate thickness control can be performed without any adverse effects.

〔Example〕

The method of the present invention will be specifically explained below based on the drawings. Second
The figure is a schematic diagram showing the implementation state of the method of the present invention, and Figure 3 is a detailed block diagram of the plate thickness control calculation device 7. In the figure, 1 is a single-stand reversible rolling mill, and la is a rolling position detector. ,l
b indicates a servo valve, 1c indicates a hydraulic device for rolling down, 2.3 indicates a reel, and S indicates a rolled material in the form of a strip. The rolled material S is fed out from the reel 2 and transferred to a deflector roll 2as rolling mill 1 and a deflector roll 3 as shown by arrows.
It is designed to be wound onto reel 3 via a. After finishing rolling to the right, when rolling to the left, reel 3
A rolled material S is fed out from the rolling mill 1 and wound onto a reel 2 through a rolling mill 1.

In addition, the armature current of reel motor M2,
By adjusting the armature current of reel motor M3,
An entry tension control device 4 and an exit tension control device 5 are provided to adjust the tension applied to the rolled material S between the rolling mill 1 and the reel 2.3. The rolled material S fed out from the reel 2 passes through the rolling mill 1 and is wound onto the reel 3 during the process of being wound up by the thickness needle 6a on the inlet side of the rolling mill 1 and by the thickness gage 6b on the outlet side of the rolling mill 1. The thickness of each part in the longitudinal direction is detected.

The outputs of the thickness gauges 6a and 6b are respectively read into the thickness control calculation device 7, the measured value of the thickness gauge 6a is sent to the feedforward control calculation device 7a, and the measurement value of the thickness gauge 6b is sent to the feedback control calculation device 7b. is input. The feedforward control calculation device 7a calculates a control signal to correct the plate thickness deviation signal [1st FyJ (a)] based on the data from the thickness gauge 6a, that is, the measured value and target value of the inlet plate thickness of the rolling mill 1. , and the feedback control calculation device 7b performs sheet thickness control to correct the sheet thickness deviation signal [Fig. 1 (b)] based on the data from the thickness gauge 6b, that is, the measured value and target value of the sheet thickness at the exit side of the rolling mill l. Calculate the signal as shown in Figure 1 (a).

The signals are outputted to the plate thickness control signal calculation device 7c as shown in (b). The plate thickness control signal calculation device 7c adds the input plate thickness control signals to calculate an overall plate thickness control signal as shown in FIG. .

A frequency to be passed through the low-pass filter 7d is set, and among the control signals input from the plate thickness control signal calculation device 7c, a signal having a frequency component lower than the set frequency (i.e., a signal with a gradual change component) passes through this to the reduction position correction amount calculation device 7f and the subtractor 7.
Output to e.

The subtracter 7e subtracts the low-frequency component control signal that has passed through the low-pass filter 7d from the control signal input from the plate thickness control signal calculation device 7c, and outputs the remaining high-frequency component control signal to the tension correction amount calculation device 7g. do.

The roll-down position correction amount calculation device 7f calculates the roll-down position correction amount based on the low-frequency component control signal input from the low-pass filter 7d, and outputs it to the roll-down position control device 13. The rolling position control device 13 outputs a predetermined signal to the servo pulp 1b based on the input rolling position correction amount and the rolling position input from the rolling position detector 1a, operates the hydraulic cylinder IC, and corrects the rolling position. .

The tension correction amount calculation device 7g calculates the tension correction amount based on the high frequency component control signal inputted from the subtractor 7e, and outputs the input side tension correction signal calculation device 7h and the output side tension correction signal according to a predetermined distribution ratio. It is distributed and output to the arithmetic unit 71. Each of the input side tension f positive signal calculation device 7h and the output side tension correction signal calculation device 71 calculate an input side tension correction signal and an output side tension correction signal based on the distributed input tension correction amount, respectively. It is output to the tension control device 4 and the outlet tension control device 5.

The input side tension control device 4 and the output side tension control device 5 have a reel current control function for the input side reel motor M2 and the output side reel motor M3, respectively, and the input side tension correction signal and the output side tension control device are respectively inputted. The armature currents to the inlet reel motor M2 and the outlet reel motor M3 are adjusted based on the tension correction signal, thereby controlling the tension of the rolled material S on the inlet and outlet sides of the rolling mill I.

FIG. 4 is a block diagram showing another structure for controlling the plate thickness vfIi used in implementing the method of the present invention, in which a bypass filter 71 is used in place of the low-pass filter 7d shown in FIG. The plate thickness control signal output from 7c is input to a bypass filter 7Il and a subtracter 711. The bypass filter, IlTough 1, has a defined minimum frequency (hereinafter referred to as the reference frequency) that can be transmitted through it, and signals with frequencies higher than this are transmitted, but signals with lower frequencies that do not reach the reference frequency cannot be transmitted. There is no such thing.

The high frequency signal transmitted through the bypass filter 71t is input to the tension correction amount calculation device 7g and the subtractor 711,
The subtracter 7m subtracts the high frequency signal that has passed through the bypass filter 71 from the plate thickness control signal input from the plate thickness control signal calculation device 7c, and calculates the reduction position correction amount using the lower frequency signal that is the difference. Output to device 7 balls.

The other configurations and operations are the same as those in the block diagram shown in FIG. 3, and their explanation will be omitted.

〔effect〕

As described above, in the method of the present invention, the plate thickness deviation signal in the longitudinal direction of the rolled material or the plate thickness control signal for eliminating the deviation is controlled at a predetermined reference frequency by tension adjustment.
Since the plate thickness control characteristics are separated into a high frequency range and a low frequency range that pass through each of the plate thickness control characteristics by adjusting the tension and rolling position, and the plate thickness is controlled by tension adjustment and rolling position adjustment, It is possible to control the plate thickness in the frequency range based on the plate thickness control characteristics of each rolling position, and it is possible to perform accurate plate thickness control, and it is possible to reduce the share of plate thickness control due to tension, which has a relatively narrow control range, and to improve the surface area. The present invention has excellent effects such as being able to perform rolling with excellent properties.

[Brief explanation of drawings]

Figures 1 (a) to (e) are graphs for explaining the principle of the method of the present invention, Figure 2 is a schematic diagram of the method of the present invention, and Figure 3 is a block diagram of the plate thickness control device used in the method of the present invention. , FIG. 4 is a block diagram of main parts showing another embodiment of the present invention. l... Rolling mill 2, 3... Reel 4... Entry side tension control device 5... Output side tension control device 6a, 6b.
...Thickness gauge 7...Plate thickness control device 7a...Feedforward control calculation device 7b...Feedback control calculation device 7c...Plate thickness control signal calculation device 7d...
-Low pass filter 7e...Subtractor 7f...Dressing position correction amount calculation device 7g...Tension correction amount calculation device
7h... Input side tension correction amount calculation device 71... Output side tension correction amount calculation device 13... Roll down position control device patent Applicant Sumitomo Metal Industries Co., Ltd. Agent Patent attorney Noboru Kono Dehe Figure 4

Claims (1)

[Scope of Claims] 1. The rolled material necessary to measure the plate thickness of each part in the longitudinal direction of the rolled material on the entry side and/or exit side of the rolling mill, and to make the plate thickness match the target value based on these measured values. The plate thickness control signal is calculated for each part in the longitudinal direction, and the plate thickness control signal is separated into a rolling position correction signal and a tension correction signal, which share the plate thickness control, and based on these signals, the rolling position, A plate thickness control method characterized by simultaneously adjusting tension. 2. The plate thickness control method according to claim 1, characterized in that the plate thickness control signal is separated into a reduction position correction signal and a tension correction signal using a low-pass filter or a bypass filter.