JPS585729B2 - Rolling mill control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for controlling a rolling mill, and more particularly to a control device that allows long materials whose thickness changes in the longitudinal direction to be manufactured with high precision. .

In order to manufacture long materials whose thickness changes in the longitudinal direction (hereinafter simply referred to as variable thickness materials) using a rolling mill, the rolling length of the rolled material (rolling length measured with reference to a point on the rolled material) is required. The length of the rolled material sent out from the machine is measured, and the target roll gap is determined from the measurement result and a function of the rolling length and roll gap given in advance, and the roll gap of the rolling mill is always adjusted to this target roll gap. It is necessary to control it to match the gap.

Therefore, how accurately the rolling length of a rolled material can be measured is an extremely important key to improving the dimensional accuracy of a product with variable thickness.

However, there is no known technique that can measure this rolling length with sufficiently high precision.

That is, as a conventional means for measuring the rolling length, a detection roller is brought into rolling contact with the surface of the rolled material on the exit side of the rolling mill.
It is known that the moving speed of the rolled material is determined from the rotational speed of the detection roller, and the rolling length is determined by integrating the moving speed. distance (hereinafter referred to as roller jump)
These roller slips and jumps easily appear as measurement errors in the rolling length.

Particularly when the longitudinal thickness changes are large and the moving speed of the rolled material is high, the rollers tend to jump.

Furthermore, when rolling a rolled material whose thickness changes in the longitudinal direction, the speed of movement of the rolled material on the exit side changes every moment, which also causes the roller to slip or jump, making it difficult to measure the rolling length. Reduce accuracy.

Therefore, in the past, it was unavoidable that the control accuracy of the rolling mill would deteriorate, and it was difficult to manufacture a variable thickness material with high dimensional accuracy by rolling.

The present invention has been made against the background of the above-mentioned circumstances, and therefore, its purpose is to improve the control accuracy of a rolling mill by improving the measurement accuracy of the rolling length, thereby achieving highly accurate thickness. An object of the present invention is to provide a control device that makes it possible to manufacture a material with a variable temperature.

Therefore, in the control device according to the present invention, the roll circumferential speed v and the roll surface movement distance s=fvdt are determined from the rotational speed of the roll that rolls the rolled material, and the surface movement distance S
is corrected by the advance rate f, and the rolling length a=s+fv
We decided to find fdt.

This advancement rate f is determined from the roll circumferential speed v obtained from the roll rotation speed and the moving speed u of the rolled material obtained from the rotation speed of the detection roller brought into rolling contact with the rolled material at the outlet side of the rolling mill. -v)/v, therefore, even in the control device according to the present invention, it is not possible to completely escape from the effects of slipping or jumping of the detection roller. is a value that is theoretically impossible, such as the advance rate f temporarily becoming a negative value, so in such a case, instead of outputting the obtained value as is, it can be theoretically considered, for example, 0. By outputting the minimum value as the advance rate f, the influence of slipping or flying of the detection roller can be significantly reduced.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in more detail below with reference to the drawings.

In FIG. 1, 1 and 2 are rolls, and bearings 18 and 1
They are supported in parallel to each other via frames 9 (not shown).

The rolls 1 and 2 are rotated by a drive device (not shown) and roll the material W to be rolled.

The thickness of this rolled material W (the exit side thickness, that is, the thickness of the product with variable thickness) can be adjusted in the longitudinal direction by changing the gap between the rolls 1 and 2 using a roll gap changing mechanism 4 including a hydraulic cylinder. can be changed to

A control device that controls the rolling mill 10 having the above configuration includes a rolling material W
A rolling length measuring section 20 that measures the rolling length of the rolling length, a roll gap commanding section 30 that calculates and commands a target roll gap that changes every moment as the rolling length changes, and a roll gap commanding section 30 that constantly adjusts the roll gap to the target roll gap. It is composed of three parts: a servo device section 40 that controls the roll gap changing mechanism 4 so as to match the gap between the rolls.

The rolling length measuring section 20 includes an encoder 3 attached to the shaft of the roll 1 as a roll rotation speed measuring device.

The encoder 3 sends a pulse signal corresponding to the rotational speed of the roll 1 to the roll circumferential speed calculation device 13.

The roll peripheral speed calculation device 13 calculates the peripheral speed v of the roll 1 from this pulse signal and the preset radius of the roll 1.

This roll circumferential speed v is transmitted to the advance rate calculation device 16 and also to the rolling length calculation device 17.

The rolling length measuring unit 20 also includes a detection roller 21 that is brought into rolling contact with the rolled material W on the exit side of the rolling mill 10, and an encoder 5 as a roller rotation speed measuring device that measures the rotation speed of the detection roller 21. The pulse signal emitted by the encoder 5 is sent to the rolled material exit velocity calculation device 1.
Sent to 4.

The rolled material exit speed calculation device 14 calculates the moving speed U of the rolled material W from this pulse signal and the radius of the detection roller 21,
The result is sent to the advanced rate calculation device 16.

The advanced rate calculation device 16 is. The moving speed U of this rolled material W,
The advance rate f=(uv)/v is calculated from the roll circumferential speed v from the roll circumferential speed calculating device 13 mentioned above.

Specifically, the rolling material moving speed u and roll circumferential speed v, which change moment by moment, are picked up at every minute time Δt, and the instantaneous value u
Find i, vi (values at i-th time), fi=(ui-v1
)/vi.

However, the advanced rate calculation device 16 does not simply output this calculation result, but also compares this calculation result with a preset setting value, and selects the larger of the calculation result and setting. It is configured to output as an hourly advance rate fi.

The setting value set in the advance rate calculation device 16 is the maximum value within a range that does not exceed the actual advance rate, for example, the rolling mill 1.
A value that changes from time to time so that it is the value obtained by removing the predicted error from the advance rate that is theoretically estimated based on the amount of reduction at 0 (including cases where it is estimated based on past data). It is desirable to set it as
It is also possible to fix the advance rate to the minimum value (that is, 0) that can theoretically exist, and in this case as well, the effects of the present invention can be obtained to some extent as will be described in detail later.

The advance rate f and the roll circumferential speed v calculated by the advance rate calculation device 16 are transmitted to the rolling length calculation device 17, where the roll surface movement distance s=fvdt is calculated and A correction by the factor f is added to calculate the rolling length a=s+fvfdt.

More specifically, at the same time that the rolling material moving speed u and the roll circumferential speed v are picked up in the advance rate calculation device 16, the instantaneous value vi of the roll circumferential speed v is calculated as the rolling length at every time Δt. From this and the instantaneous value fi of the advance rate f calculated by the advance rate calculation device 16, the roll surface movement distance S is calculated as S÷Σv1△
t, and further the rolling length a is a÷s+ΣVi
It is calculated as fiΔt.

The calculated rolling extension length a is transmitted to the roll gap command section 30.

The roll gap command unit 30 uses a roll gap calculation device 9 to set a function (hereinafter referred to as gap relationship) h=g(a) between the rolling length a and the roll gap h and an initial value ho of this function. A function setting device 11 is provided.

The gap function h = g (a) is determined in advance based on the function b = g (a) of the longitudinal position l of the product with variable thickness and the plate thickness b, and requires particularly high accuracy. Except in case
b=g(l) itself can be substituted for h=g(a).

In addition, the gap function h=g(a) is given as a function corresponding to one cycle of thickness change of a material with a variable thickness, and generally the material with a variable thickness is divided into several sections, and a corresponding one is assigned to each section. is given as a set of expressions.

The roll gap calculation device 9 calculates a target roll gap that changes moment by moment in accordance with the rolling length based on the output of the rolling length calculation device 17, the gap function h=g(a), and its initial value ho. is calculated and sent to the next servo unit 40 via the digital-to-analog converter 15.

The servo device section 40 is equipped with a differential transformer-type roll gap measuring device 6 to measure the roll gap between the rolls 1 and 2, and the actual roll gap measured by this roll gap measuring device 6 is always used in the roll gap calculation. The roll gap changing mechanism 4 of the rolling mill 10 is controlled to match the target roll gap from the device 9.

That is, when a difference occurs between the target roll gap and the measured roll gap, the servo amplifier 8 outputs a voltage corresponding to the difference to the servo valve 7, and the servo valve 7 outputs a voltage corresponding to this output. As a result, pressure oil is sent from the hydraulic pressure generator 12 to the hydraulic cylinder of the roll gap changing mechanism 4, and the gap between the rolls 1 and 2 is changed so that the measured roll gap always matches the target roll gap. It is to make it.

The operation of the control device configured as described above will be described below, taking as an example a case where a variable thickness material having a plurality of continuous tapered leaf materials having the shape shown in FIG. 2 is manufactured.

As is clear from the figure, the tapered leaf material shown in Figure 2 has a thick parallel part at the center, a relatively thin parallel part at both ends,
It consists of a total of five parts, including two tapered parts that continuously connect these parts, and therefore the function b =
g(l) is expressed by five different equations for each part.

For ease of understanding, assuming that the function b=g(l) can be directly substituted for h=g(a), it and its initial value bo are set in the function setting device 11.

Further, the radius of the roll 1 is set in the roll circumferential speed calculation device 13, and 0 is set as the setting value in the advanced rate calculation device 16.

The preparation is now complete. The rolling mill 10 is operated, and the encoder 3 begins to generate a pulse signal corresponding to the rotational speed of the roll 1.

When the rolled material W is bitten by the rolls 1 and 2, it is detected by a load cell etc. installed in the rolling mill 10,
It is desirable to set the roll gap calculation device 9 so that the roll gap can be quickly adjusted to the initial value of the gap function.

When the tip of the rolled material W reaches the detection port 21 for detecting the amount of movement, the encoder 5 starts emitting a pulse signal corresponding to the moving speed u of the rolled material W, and from this moment the cycle by the control device is started. .

That is, based on the pulse signal from the encoder 5 and the pulse signal from the encoder 3 described above, the compression length measuring section 20
, the rolling length a is determined, and based on this rolling length a, the roll gap command unit 30 sets a target roll gap that changes moment by moment (it is also possible for the variable thickness material to be produced to repeat the shape shown in FIG. 2). In this case, the target roll gap is constant in the parallel section), and the servo unit 40 controls the roll gap changing mechanism 4 of the rolling mill 10 according to this finger. .

When one cycle of roll gap control is completed, the roll gap calculation device 9 returns to the first equation for the gap opening number and starts calculating the series of equations again, and by repeating this, the taper leaf shown in FIG. A continuously varying thickness of material is produced.

It should be noted here that in the control device according to the present invention, the rolling length a is calculated by simply integrating the rolled material exit speed u determined by the rolled material exit speed calculation device 14 (including approximate calculation by integration). ), but is calculated based on the surface movement distance S of the roll 1 itself that rolls the rolled material W, and is corrected by the advance rate f, so the rolling length a can be determined with extremely high accuracy. This is what is required.

In other words, if the rolling length is determined only by the output of the rolled material exit velocity calculating device 14, if slipping or skipping occurs on the detection roller 21, this will directly appear as an error in the rolling length a. In the control device according to the present invention, this slip or jump does not directly appear as an error.

Now, in the control device according to the present invention, if the detection port-ra jumps and the calculated value of the rolled material exit speed u temporarily becomes 0, then the advance rate fi calculated in the advance rate calculation device 16 = (ui-vi)/Vi becomes -1.

Therefore, if the advance rate fi (=-1) is sent to the rolling length calculation device 17 as it is, then the correction value ΣVi based on the advance rate fi
fiΔt temporarily decreases (this is theoretically impossible), and the calculated value of the rolling length a becomes shorter than the actual rolling length by that amount.

However, since the advanced rate calculation device 16 has a set value of 0, which is the minimum value of the advanced rate that can theoretically exist, the advanced rate calculation device 16 calculates the advanced rate -
1 and the set value 0 are compared, and the larger value 0 is outputted to the rolling length calculation device 17 as the advance rate fi.

Therefore, the correction value ΣvifiΔt based on the advance rate fi calculated in the rolling length calculation device 17 only temporarily stops increasing and does not decrease, and the detection roller 21 jumps with respect to the calculated value of the rolling length a. 1 influence is reduced, and the measurement accuracy of the rolling length is improved.

Note that in the above explanation, in order to facilitate understanding, it is assumed that the detection roller temporarily stops completely; however, if ui<v
If i, the advance rate fi becomes a negative value, and 2. In this case, the effects of the detection roller 21 flying, etc. can be reduced by a rough method of fixing the set value of the advance rate calculation device 16 to 0.

Furthermore, if the setting value of the advance rate calculation device 16 is set as a value that changes moment by moment so as to be maximum within a range that does not exceed the actual advance rate as described above, the comparison of the detection roller 21 This makes it possible to eliminate the effects of even small slips, further improving the accuracy of measuring rolling length.

In addition, in the above embodiment, one of the pair of rolling rolls was moved to change the roll gap, but both rolling rolls were moved symmetrically with respect to the center plane in the thickness direction of the rolled material. It is also possible to change the roll gap.

Furthermore, in the above embodiment, the rolling length and the target roll gap were calculated digitally, and the roll gap changing mechanism was controlled in an analog manner. It is also possible to control the roll gap changing mechanism digitally.

Although other examples will not be given in detail, it is of course possible to make various modifications and improvements without departing from the spirit of the present invention, and the present invention should be construed as limited to the above embodiments. It's not a thing.

As described in detail above, the present invention is equipped with a rolling length measuring section that can measure the rolling length with high accuracy, which is an extremely important factor in rolling a long material whose thickness changes in the longitudinal direction. Since the present invention provides a rolling mill control device, it has an excellent effect of improving the control accuracy of the rolling mill and making it possible to manufacture a long material whose thickness changes in the longitudinal direction with high dimensional accuracy.

[Brief explanation of the drawing]

FIG. 1 is a schematic view showing an embodiment of the present invention, and FIG. 2 is a perspective view showing an example of a product manufactured by the apparatus shown in FIG. 1.2...Roll, 3...Encoder (roll rotation speed measurement device) 4...Roll gap changing mechanism, 5...Encoder (roller rotation speed Measuring device), 6...Roll gap measuring device, 7.
... Servo valve, 8 ... Servo amplifier, 9
...Roll gap calculation device, 10...Rolling mill, 11...Function setting device, 12...
・Hydraulic pressure generator, 13...Roll peripheral speed calculation device, 14...Rolled material exit speed calculation device, 15...
...Digital to analog converter, 16...
・Advanced rate calculation device, 17... Compilation length calculation device, 20... Compilation length measurement unit, 21...
Detection port-ra, 30...Roll gap command section, 40
... Servo device section, W ... Rolled material.

Claims (1)

[Scope of Claims] 1. A rolling mill equipped with a pair of rolls arranged parallel to each other, at least one of which is rotated by a drive device, and a roll gap changing mechanism that changes the gap between the pair of rolls. A control device for manufacturing a long material whose thickness changes in the longitudinal direction, comprising: (a) a roll rotation speed measurement device that measures the rotation speed of the roll; and (b) the roll rotation speed. a roll circumferential speed calculation device that calculates the roll circumferential speed v from the output of the measuring device and the radius of the roll; d) a roller rotational speed measuring device for measuring the rotational speed of the detection port; (e) an output of the roller rotational speed measuring device and the detection port;
(c) a rolled material exit speed calculation device that calculates the exit speed u of the rolled material from the radius of the roll; /v is calculated, and the calculated value is compared with a set value set within the range from the maximum value of the advanced rate to 0, which is estimated to have no risk of exceeding the actual advanced rate from theoretical calculations or actual data. , an advance rate calculation device that outputs the larger of the calculated value and the set value as the advance rate f, and (g) calculates the roll surface movement amount s=fv dt based on the output of the roll circumferential speed calculation device. Also, a rolling length calculation device which corrects this based on the output of the advance rate calculation device and calculates the rolling length a=s+fv f dt of the rolled material; (h) the output of the rolling length calculation device and a roll gap calculation device that calculates a target roll gap from a preset function h=g(a) of rolling length a and roll gap h and an initial value ho of the function; A roll gap measuring device is provided for actually measuring the roll gap of the rolling mill, and the roll gap changing mechanism is controlled so that the output of the roll gap measuring device always matches the target roll gap calculated by the roll gap calculating device. A rolling mill control device comprising: a servo device.