JPH0133250B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for automatically controlling the thickness of a rolled material by controlling the tension and reduction amount of the rolled material.

[Prior art]

In general, as a method of controlling the thickness of a rolled material by adjusting the tension and reduction amount, for example, JP-A-50
A method of independently adjusting the tension and the amount of reduction is known, as in No. 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 mainly based on tension adjustment with excellent responsiveness is often required. However, this method of controlling the plate thickness by adjusting the tension has a problem in that the range in which the tension can be adjusted is narrow and the plate quickly reaches a saturated state, making it impossible to control the plate thickness.

In order to solve the problem of saturation of plate thickness control due to such a narrow tension adjustment range, when the tension reaches saturation or exceeds the lower limit and plate thickness control by tension becomes impossible, the plate thickness can be adjusted by adjusting the rolling position. A method has been proposed in which a part of the control amount is shared to eliminate the tension saturation state (Japanese Patent Application Laid-open No. 40455/1983).

[Problem that the invention seeks to solve]

By the way, in the above-mentioned method in which plate thickness control is partly performed by adjusting the rolling position, the tension is controlled by adjusting the rolling position only when the tension reaches its saturation and exceeds the lower limit. Since the tension is set to return to within the upper and lower saturation limits, after the tension exceeds the upper and lower saturation limits, adjusting the reduction position will cause the tension to return to within the upper and lower saturation limits during the transition period. There was a problem in that the plate thickness could not be controlled by tension adjustment in some cases.

[Means for solving problems]

The present invention has been made in view of the above circumstances, and its purpose is to change tension control between the saturation and lower limits, that is, between the lower limit of saturation, which is smaller than the upper limit of saturation, and which is larger than the lower limit of saturation. A lower limit value is determined, and when the tension correction amount reaches the lower limit value in this reduction transfer, part or all of it is converted into the reduction position change amount that gives the same plate thickness control effect, and transferred to the reduction position change amount. Automatic plate thickness reduces the amount of tension correction, eliminates defects in plate thickness control due to tension control saturation, prevents transient plate thickness control disturbances, and improves plate thickness accuracy. The present invention provides a control method and device thereof.

The method of the present invention measures the thickness of a rolled material at the input side and/or exit side of the rolled material, adjusts the tension of the rolled material to match the measured value, and controls the thickness. The amount of tension correction required to match the target value is determined, and the entire amount of tension correction is determined so that the amount of tension correction exceeds the saturation of tension control, the reduction transfer is set between the lower limit value, and the amount of tension correction is kept within the lower limit value. Alternatively, a part of the tension correction amount is converted into a reduction position change amount that provides the same plate thickness control amount, and the tension correction amount is transferred to the reduction position for adjustment.

〔Example〕

Hereinafter, an embodiment will be specifically described in which the present invention is applied to a reversible rolling mill in which the plate thickness is controlled by a combination of strip tension feedback control and feedback control. FIG. 1 is a control block diagram showing a mode in which the method of the present invention is implemented by an automatic sheet thickness control device according to the present invention (hereinafter referred to as the device of the present invention), and in the figure, 1 is a single stand reversible type control device. Rolling machine, 1a is a rolling device, 1b is a rolling position detector, 1c is a load cell, 2 and 3 are reels, S
indicates a strip. The strip S is fed out from a reel 2, passed through a deflector roll 2a, a rolled material 1, and a deflector roll 3a as shown by the arrow, and then wound onto a reel 3. After the rightward rolling is completed, the strip S is unwound from the reel 3 and wound onto the reel 2 through the rolling mill 1 during the leftward rolling.

In addition, reel motors M 2 and 3 are connected to reels 2 and ₃ , respectively.
By adjusting the armature current of reel motor _M2 and the armature current of reel motor _M3 by adjusting the terminal voltage of _M3 , the tension of the strip S between the rolling mill 1 and the reels 2 and 3 can be adjusted. An inlet tension control device 4 and an outlet tension control device 5 are provided for adjustment.

The process of controlling plate thickness using the method and apparatus of the present invention will be specifically explained below. The strip S fed out from the reel 2 passes through the rolling mill 1 and is wound onto the reel 3.
According to a, the thickness total 6 on the exit side of the rolling mill 1
The plate thickness of each part in the longitudinal direction is detected by b.
The measured value by the thickness gauge 6a is read into the feedback control device 7, and the thickness gauge 6b is read into the feedback control device 8. The feedforward control device 7 tracks the thickness measurement positions of the strip S until they reach the rolling mill 1 based on the rolling speed and backward movement rate input from a speedometer (not shown), and also tracks the thickness measurement positions of the strip S until they reach the rolling mill 1. At the same time, each measured value is compared with a pre-input target value, a tension change amount for eliminating the deviation is calculated, and this is output to the tension setting amount calculating device 9.

On the other hand, the feedback control device 8 is connected to the rolling mill 1.
The thickness of each part of the strip S in the longitudinal direction is read from the thickness gauge 6b placed on the exit side of the rolling mill, and this measured value is compared with the target thickness on the exit side of the rolling mill, and the amount of tension change required to eliminate the deviation is calculated. The calculation is performed by proportional and integral operations, and the calculation result is output to the tension setting amount calculation device 9. The tension setting amount calculation device 9 calculates each tension setting amount for the input side and exit side of the rolling mill 1 based on each input tension change amount and a predetermined tension reference value, and individually calculates the tension correction amount calculation device 10.
It is configured to output to.

The tension correction amount calculation device 10 calculates a tension value ΔTr that can give the same plate thickness change as the reduction change amount input from the reduction change calculation device 12, which will be described later, from each tension setting amount input from the tension control amount calculation device 9. After subtraction, the remaining tension setting amount and side tension correction amount are output to the output saturation device 11 and the reduction change calculation device 12, respectively.

The output saturation device 11 is set with an effective tension control range for plate thickness control, that is, upper and lower saturation limits. This output saturation device 11 does not output any more when the tension correction amount reaches the upper and lower saturation limit values, that is, the tension control limit value, and is a conventionally known device. The present invention is characterized by a reduction transfer amount calculation device 12, and this reduction transfer amount calculation device 12 has a range (for example, about 40 to 80%) narrower than the above-mentioned saturation and lower limit values, in other words, saturation. Upper and lower limit values for reduction transfer are set, which are smaller than the upper limit value and larger than the saturation lower limit value. Therefore, if the tension correction amount currently output from the tension correction amount calculating device 10 is equal to or exceeds the lower limit value of the reduction transfer, the tension correction amount is within the range of the lower limit value of the reduction transfer. Part or all of the tension correction amount so that it remains at (this correction amount is ΔTr)
The rolling position change amount ΔS that yields the plate thickness control amount Δh equivalent to Δh is determined according to the following formula (1), and this is output to the rolling position control device 13 and at the same time, it is also output to the tension correction amount calculating device 10. .

ΔS/ΔTr=∂P/∂Tr/M...(1) However, ∂P/∂Tr: Effect coefficient of tension change on pressure load M: Mill spring Let us explain the basis of equation (1). The relationship between the plate thickness control amount Δh, the tension change amount ΔTr, and the rolling position change amount ΔS is given by the following equations (2) and (3), respectively, and equation (1) can be derived from these equations (2) and (3). It can be derived by eliminating Δh.

Δh=∂P/∂Tr/M+Q・ΔTr...(2) Δh=M/M+Q・ΔS...(3) However, Q: Plasticity coefficient of the strip The tension correction amount output from the tension correction amount calculation device 10 is the reduction When the lower limit value is reached or exceeded in transfer, the rate at which the tension correction amount is transferred to the reduction position change amount is not particularly limited, and as a result, the tension correction amount is within the range of the lower limit value in reduction transfer. Just stay. For example, if the entire tension correction amount is transferred to the reduction position change amount for adjustment, the tension correction amount to be shared for sheet thickness control becomes zero, and sheet thickness control is performed over a wide range for subsequent sheet thickness fluctuations. There are benefits that can be achieved.

Further, during rolling of a single material, the rolling position correction amount is integrated each time it is calculated. Next, when the reduction position change amount ΔS is sent from the reduction transfer amount calculation device 12 to the tension calculation device 10, the tension calculation device 10 calculates (1).
ΔT _T is calculated using the relationship in the equation, and subtracted from the tension setting amount from the tension setting amount calculating device 9 as described above. Alternatively, it is clear that the tension correction amount _ΔTT may be sent as is from the reduction transfer amount calculation device 12 to the tension calculation device 10.

In the output saturation device 11, the amount of tension correction based on the input feedback data from the feedback control device 7 and the amount of tension correction based on the feedback data from the feedback control device 8 are adjusted as a whole. This is regarded as a tension correction amount, and a control signal is output to the input side tension control device 4 and the output side tension control device 5 according to a predetermined sharing ratio, and the reel motor is controlled to realize each tension correction amount.
The armature currents of M ₂ and M ₃ are adjusted, and the strip S
tension is controlled. Input and outlet tension control device 4,
There is no particular limitation on the sharing ratio of plate thickness control to 5, and usually the entry side tension control device 4
In particular, when it is necessary to widen the plate thickness control range, the control signal is also output to the outlet tension control device 5.

The reduction position change amount is output from the reduction transfer amount calculating device 12 to the reduction position control device 13 at a speed corresponding to the response speed of the reduction control, and the reduction position control device 13 reads the reduction position from the sensor 16 and controls the reduction motor M. ₁ to adjust the rolling position.

Figure 2 A, B, C, and D are graphs showing the above-mentioned plate thickness control contents, and in each case, the horizontal axis shows time, and the vertical axis shows the amount of tension correction in the case of Figure 2 A. , Fig. 2B shows the reduction transfer amount, Fig. 2C shows the actual tension, and Fig. 2D shows the thickness deviation. Now, as shown in Fig. 2A, the tension correction amount output from the tension correction amount calculation device 10 is at the _l1 position, which is narrower than the upper and lower saturation limits Tmax and Tmin set in the output saturation device (40 to (approximately 80%) When the set upper and lower limit values TWmax and TWmin of the reduction transfer reach TWmax, the reduction transfer amount calculating device 12 calculates the amount of change in the reduction position required to make the tension correction amount zero, for example. and at a speed according to the responsiveness of the reduction control system.
Gradually increase from the _l1 position to the _l2 position as shown in Figure 2B,
l After _{the 2nd} position, it is output to the reduction position control device 13 so that the required reduction transfer amount is reached. Press down position control device 1
In step 3, a control signal is output to the motor _M1 in order to adjust the screw down position in accordance with the amount of change in the screw down position.

Further, the reduction position change amount is outputted from the calculation device 12 to the tension correction amount calculation device 10, and the tension change amount that produces the same plate thickness correction effect as the reduction transfer amount is subtracted from the tension control amount from the tension control amount calculation device 9. Therefore, the tension correction amount, which is the output from the tension correction amount calculating device 10, is rapidly reduced and returns to a substantially steady state at the _l2 position. Also, based on this tension correction amount, the input side tension control device 4 and/or the output side tension control device 5
The tension in the strip S returns to a steady state as shown in Fig. 2 (c), and the lower limit value TWmax,
Feed forward and/or within the range of TWmin
Alternatively, feedback control will be performed.

As a result, as shown in Figure 2 D, the plate thickness deviation is due to tension→
Even during the transition period of changing the rolling position, no particular variation occurs, and the strip S with excellent thickness accuracy can be obtained. By the way, the plate thickness
As a result of applying the method and apparatus of the present invention in the process of cold rolling a 0.25 Qmm strip, it was confirmed that the thickness deviation, which was conventionally ±4 μm, could be reduced to ±2 μm.

In addition, although the above-mentioned embodiment explained the structure in which the method and apparatus of the present invention are applied to a reversible rolling mill with a single stand, the present invention is not limited thereto, and can be applied to a rolling mill having a plurality of stands. Furthermore, in the above-mentioned embodiments, the tension control is explained using both the feedback control and the feedback control, but the tension control can also be applied to the case where only one of the feedback control and the feedback control is used. . In addition, for a plurality of devices, a computer may also serve as the computer.

〔effect〕

As described above, in the method and apparatus of the present invention, when the tension control is saturated, the reduction is transferred within a narrower range than the lower limit, and when the lower limit is reached, part or all of it is transferred to the amount of change in the reduction position. Since the amount of tension correction is reduced by the same amount, the effect on the plate thickness is small, and the amount of tension correction is saturated.
This has excellent effects on improving the quality of rolled materials, such as eliminating the inconvenience of not being able to control the plate thickness due to reaching the lower limit.

[Brief explanation of drawings]

Fig. 1 is a control block diagram showing a mode in which the method of the present invention is implemented by the apparatus of the present invention, Fig. 2 A, B,
C and D are graphs showing plate thickness control patterns. DESCRIPTION OF SYMBOLS 1... Rolling mill, 2, 3... Reel, 4... Entrance side tension control device, 5... Output side tension control device, 6a,
6b... Thickness gauge, 7... Feedback control device, 8... Feedback control device, 9... Tension control amount calculation device, 10... Tension correction amount calculation device, 11... Output saturation device, 12... ... Rolling down transfer calculation device, 13... Rolling down position control device.

Claims (1)

[Claims] 1. The thickness of the rolled material is measured at the entrance and/or exit side of the rolling mill, and the tension of the rolled material is adjusted so that the measured value matches the target value, thereby controlling the thickness. In this method, the amount of tension correction required to match the measured value with the target value is determined, and when this amount of tension correction reaches the lower limit value, the amount of tension correction is determined on the saturation of tension control and the lower limit value. In order to keep the value between the upper and lower limits of the reduction transfer, all or part of the tension correction amount is converted into the reduction position change amount that gives the same plate thickness control amount, and the tension correction amount is converted into the reduction position change amount. An automatic plate thickness control method characterized by adjusting by transferring to. 2. A rolling mill, a device for controlling the tension of the rolled material at the entrance and/or exit side of the rolling mill, a thickness gauge for measuring the thickness of the rolled material at the entrance and/or exit side of the rolling mill, and In an automatic plate thickness control device comprising means for calculating a tension setting value and a tension correction amount for a rolled material in order to make the measured value of a thickness gauge match a target value, the means may be configured to When the predetermined upper and lower limits of the reduction transfer are set, and the tension correction amount reaches the upper and lower limit values of the reduction transfer, all or part of the tension correction amount is a device for converting the amount of change in the reduction position to an amount of change in the reduction position that provides an equivalent plate thickness control amount, a device that calculates the tension correction amount based on the tension setting value and the amount of change in the reduction position, and the amount of change in the reduction position. 1. An automatic plate thickness control device comprising: a device for adjusting a rolling position based on .