JPH0613128B2 - Meander controller - Google Patents

Description

TECHNICAL FIELD The present invention relates to an apparatus for controlling meandering of a rolled material.

[Prior Art] In the rolling operation, there is a phenomenon in which the rolled material cannot stay in the center of the roll due to the conditions during rolling and moves toward the end of the roll as the rolling progresses as shown in FIG. It is well known and is called meandering.

The meandering of the rolled material will be briefly described below.
The figure shows a state in which the rolled material a has deviated from the center of the work roll b to the right side for some reason. In the case of FIG. 4, the roll gap becomes uneven on the left and right, and the right side gap is It is wider than the left side. By the way, although the peripheral speed of the work roll b is uniform on the left and right, the gap on the right side is wider, so the volumetric flow rate of the rolled material per unit time is larger on the right side. Further, if the thickness of the rolled material on the entry side is symmetrical, the material is drawn in earlier on the side of the larger volumetric flow rate. As a result,
As shown in FIG. 5, the rolled material a moves toward the right side on the entrance side (Δx), and a camber (Δy) occurs on the exit side. Therefore, the difference between the left and right roll gaps is further increased, and the rolled material a approaches the right end more rapidly, and a phenomenon of meandering occurs. Along with that, the camber also increases.

To prevent such meandering and accompanying camber,
It is effective to carry out rolling under the condition that the rolled material has a convex crown. However, in recent years, demands for quality improvement and yield improvement of rolled materials have become strict, and it is required to reduce the number of convex crowns as much as possible and perform rolling so as to have a uniform thickness distribution in the longitudinal direction and the width direction. Under these conditions, meandering of the rolled material is likely to occur, and stable operation is difficult.

In recent years, as one of the means for preventing the meandering, when the rolled material meanders, the forces applied to the left and right load cells c and d (see FIG. 4) change.
Means have been proposed to try to prevent this by moving the reduction device so as to narrow the roll gap on the side of increased load.

However, with the above-mentioned means, there is a problem that the load output change due to meandering and the load output change due to the operation of the rolling down device are overlapped, and the control system is unstable and divergent vibration is likely to occur, and the accuracy is insufficient. However, it has the drawback of not being practically usable at all.

Further, as can be seen from the above-described meandering mechanism, since meandering is an unstable phenomenon that diverges rapidly once it occurs, a meandering control device is required to compensate for a response delay of a reduction device or the like to obtain a fast response. However, there is a drawback that it is difficult to adjust the control device because it is necessary to enter differential control in addition to proportional control.

Therefore, in order to solve the above problems, the present inventors have
For example, we have proposed a meandering control means as shown in Japanese Patent Application No. 58-65109. In the meandering control means, a detector for detecting the width end position of the rolled material is provided on the working side and the driving side of the rolling mill, and a calculator for calculating the meandering amount by calculating the difference between the output signals of the detectors. And a setting device for giving a target position of the rolled material, and a device for comparing and calculating the output signal of the computing device and the target signal of the setting device, and a device for processing the signal obtained by the device to drive the working side. And a meandering control adjusting device for outputting as a rolling reduction signal on the side, and the working side by a signal for the rolling reduction,
The roll gap on the drive side is changed.
Further, by detecting the meandering amount of the rolled material on the entrance side of the rolling mill, the meandering amount caused by the inclination of the rolled material can be detected at the same time, so only differential control is not required in the controller and only proportional control is required.

[Problems to be Solved by the Invention] However, when the above-mentioned meandering control means is applied to tandem rolling, in a steady state (when tension is applied to the rolled material), the proportional gain of the meandering control adjusting device is set to the tension. The inventor has found through theoretical examination and actual equipment tests that the meandering cannot be corrected unless the value is raised several times the theoretical value in the case of zero. Therefore, when the rolled material passes through a predetermined rolling mill in this state, the rolled material loses tension, resulting in overgain, and the phenomenon that the meandering control becomes unstable at the tail end of the rolled material occurs. The reason for this will be described with reference to FIGS. 6 and 7. When tension is applied to the rolled material a, the rolling material a is meandered by the meandering control (the driving side in FIGS. 6 and 7). When the roll gap is closed and the rolled material a is returned to the center position of the rolling mill, the material on the meandering side stretches,
A tension distribution as shown in FIG. 7 is generated in the width direction of the rolled material a on the entrance side of the rolling mill. That is, the rear tension stress on the side where the roll gap is closed is lower than the rear tension stress on the side where the roll gap is opened. This is equivalent to an increase in the deformation resistance on the side that apparently closes the roll gap (because the tension on the entrance side has decreased), and as a result, the rolling reaction force on the roll increases and the roll gap increases. Therefore, the meandering control cancels the effect of closing the gap. As described above, when tension is applied, the effect of leveling due to the meandering control is canceled by the feedback of tension. Therefore, it is necessary to set the proportional gain of the meandering control adjusting device to a considerably large value to enhance the effect of leveling. On the other hand, when the tension of the rolled material is zero, the effect of leveling by the meandering control is not canceled by the tension, so if the proportional gain is left as it is when the tension is applied, the meandering control is effective. As a result, it becomes difficult to perform stable meandering control.

Then the determined by the proportional gain K _p ^N and the characteristic equation relationship derivative gain T _d ^N normalized for example when stably perform meander control in the case of ignoring the tension of the rolled material 8
As shown in the figure. A region surrounded by a solid line in FIG. 8 is a range where the meandering control does not become unstable.

In the graph of FIG. 8, the proportional gain K is obtained when K _p ^N = 1.
_p = 2.2 μm / mm, and when T _d ^N = 1, the differential gain T _d = 0.045 sec. Under the current rolling conditions, if the effect of feedback due to tension is not considered, the proportional gain and differential gain of the meandering control adjusting device are maximum, K _p
^max. = 2.2 × 7.4≈16 μm / mm, T _d ^max. =
0.045 × 30 = 1.35sec. By the way, in the actual machine test, when tension is applied, the proportional gain is, for example, K _p = 50.
The leveling effect was not sufficiently obtained unless it was set to about μm / mm. Therefore, from the graph shown in FIG. 8 as well, it can be seen that if the gain setting during steady rolling is left as it is, over-gain occurs when the rolling material slips out.

The characteristic equation that is the basis for creating the graph showing the relationship between the proportional gain K _p ^N and the differential gain T _d ^N shown in FIG. 8 was derived as a result of the invention of the inventors of the present application. , The details are Ishikawajima Harima Technique Vol. 26, No. 1 (Showa
(Issued in January 1986), page 3 to page 4. Thus, the graph of FIG. 8 is obtained from the inequality obtained by applying the Routh stability determination condition to the characteristic equation.

_{^{Also, K p N, T d N}} , K p, although specific numerical values of T _d is the theoretical value, after the rolled material tail even in actual operation has passed through the rolling mill in the upstream one of the required rolling mill The value of about the above-mentioned specific numerical value is used for the control of.

FIG. 9 shows an example of simulation when the rolled material slips out. In this example, the proportional gain K _p = 30 μm / mm and the differential gain T _d = 0, and stable control is possible when there is a steady rolling tension. It can be seen that when the tension is applied, the tail end of the rolled material largely shakes to the left and right, and the meandering control becomes unstable. For the reasons described above, T _d = 0 during steady rolling in this method.
But it can be controlled stably.

The present invention is based on the above-mentioned knowledge, and during rolling by a tandem rolling mill, it is possible to perform more stable meandering control in the downstream rolling mill even after the rolled material tail end slips through the upstream rolling mill. It was done as.

[Means for Solving Problems] The present invention provides a rolled material width end position provided on at least one working side or driving side of a required rolling mill in the tandem rolling mill. And a meandering amount calculation device for calculating a meandering amount by calculating a difference between output signals of the end position detector, an output signal of the meandering amount calculation device and a target position signal of the rolled material. And a comparison calculation device for comparing and calculating the rolled material obtained by the comparison calculation device when the rolled material is bitten by any one of the required rolling mill and one rolling mill upstream of the required rolling mill. When a rolling reduction signal in a steady state is obtained from the signal and output, and when the rolled material tail end slips out of the rolling mill one upstream above, a differential gain is applied to the reduction correction signal based on the slipping out signal Meandering control adjusting device for obtaining and outputting the reduction correction signal of And the roll gaps on the working side and the driving side of the required rolling mill are changed by the respective reduction correction signals.

[Operation] The meandering amount of the rolled material is obtained from the end position of the rolled material width detected by the edge position detector, and the reduction correction signal is obtained from the difference between the meandering amount and the target position of the rolled material. The left and right roll gaps are adjusted by the signal and the meandering control is performed,
When the tail end of the rolled material passes through one rolling mill upstream, based on the trailing edge signal, differential gain is applied to the rolling reduction signal at steady state to obtain the rolling reduction signal at the time of trailing edge.
The meandering control is continuously performed by the reduction correction signal.

[Examples] Examples of the present invention will be described below with reference to the drawings.

1 and 2 show an embodiment of the present invention, in which 1a is an upstream rolling mill, 1b is a downstream rolling mill, and 2 is a load detector for detecting the rolling load of the upstream rolling mill 1a. Is.

The downstream rolling mill 1b has upper and lower work rolls 3,4, upper and lower backup rolls 5,6, and lower backup roll chock 7, which supports both axial ends of the upper and lower backup rolls 5,6.
8.The lower backup roll chocks 7, 8 are equipped with hydraulic cylinders 9, 10 for applying a rolling force to roll the rolled material 11, and the pressure oil flowing in and out of the left and right hydraulic cylinders 9, 10 is The displacement detectors 15 and 16 for detecting the movement of the pistons of the hydraulic cylinders 9 and 10 are attached to the hydraulic cylinders 9 and 10 while controlling the amount by the servo valves 13 and 14, Signal and meander control controller 24
Further, addition amplifiers 17 and 18 for comparing the signal transmitted through the addition amplifier 25 are provided. The left and right roll gaps are set by controlling the amount of pressure oil that flows in and out of the hydraulic cylinders 9 and 10 by the servo valves 13 and 14, and the fluctuation of the roll gap is determined by the pistons of the hydraulic cylinders 9 and 10. Displacement detectors 15 and 16 that detect movements are indirectly measured by, and if there is a difference compared with the set signal by summing amplifiers 17 and 18, it is corrected by controlling the servo valves 13 and 14 with the difference. To In addition, the upstream and downstream rolling mill 1b
The end position detectors 19a and 19b that detect the width end position based on the light emitted from the rolled material 11 are installed on the left and right of the entrance side of the, and the difference between the signals from the respective end position detectors 19a and 19b. , Ie rolled material
The meandering amount of 11 is calculated by the calculator 20, the meandering amount and the target signal from the setting device 21 are compared and calculated by the comparison calculator 22, and the obtained meandering amount deviation signal 23 is processed by the meandering control adjuster 24. Summing amplifier
It is configured to be added to the summing amplifiers 17 and 18 as left and right reduction correction signals 26 and 27 via 25.

The meander control controller 24 includes a controller body 28 and the controller body 28.
Is provided in parallel with the differentiator 29, and a change-over switch 31 is connected to the input side of the differentiator 29 so as to be turned on by a rolled material trailing edge signal 30 from the upstream rolling mill 1a.

The output of the regulator 24 is, for example, when the rolled material 11 approaches the working side, the roll gap on the working side is tightened to open the roll gap on the driving side, and the rolled material 11 approaches the driving side. In this case, contrary to the above, the direction is determined so that the roll gap is controlled, and the roll amplifier is added to the summing amplifiers 17 and 18.

When the rolling material 11 is held in both the upstream rolling mill 1a and the downstream rolling mill 1b and tension is applied to the rolling material 11 on the downstream rolling mill 1b entrance side, the load of the upstream rolling mill 1a is in a steady state. From the detector 2, the trailing slip signal 30 is sent to the meandering control controller 24 of the downstream rolling mill 1b.
Is not given. Therefore, in the meandering control controller 24 of the downstream rolling mill 1b, the changeover switch 31 is off.

In the calculator 20, the meandering amount is obtained from the width end position of the rolled material 11 detected by the end position detectors 19a and 19b, and the meandering amount is the rolling material meandering amount from the setter 21 in the comparison calculator 22. The meandering amount deviation is obtained by comparison with the target value, and the meandering amount deviation signal 23 output from the comparison computing unit 22 is given to the meandering control controller 24 and multiplied by a proportional gain K _p in the controller body 28. , Adder amplifier 25, and add-up amplifier as reduction correction signals 26, 27
Given to 17,18. Therefore, in the adding amplifiers 17 and 18, the displacement signals of the pistons of the actual hydraulic cylinders 9 and 10 are compared with the reduction correction signals, and the servo signals 13 and 14 are compared with the difference signals.
Controls the inflow and outflow of pressure oil to the hydraulic cylinders 9 and 10,
As a result, the left and right roll gaps are changed, further progress of the meandering is stopped by the mechanism described above, and the rolled material 11 is returned to the target value given by the setter 21.

When the tail end of the rolled material 11 slips out from the upstream rolling mill 1a, the slip detector 30 is sent from the load detector 2 of the upstream rolling mill 1a to the meandering control controller 24 of the downstream rolling mill 1b, Missing signal 30
Thereby, the changeover switch 31 is turned on. Therefore, the meandering amount deviation signal 23 is input to both the controller main body 28 and the differentiator 29, and the signal subjected to the proportional gain K _p is sent from the controller main body 28 to the summing amplifier 25, and then the differentiator 29. The differentiated signal is sent to the addition amplifier 25, and the signal added by the addition amplifier 25 is output as a reduction correction signal when the tail end of the rolled material is missing. In this case, if the meandering amount deviation signal is V, the summing amplifier 25 Is calculated and output. In this way, when the differential gain is applied, the deviation width of the meandering amount of the tail end of the rolled material after slipping off the tail end of the upstream rolling mill decreases as shown in FIG.
The tail tip swings to the left and right as it slips through 1b, but it is controlled without any problems. In this case, the control system remains unstable because the proportional gain is not reduced, but the control effect is reduced by differentiation so that rolling can be performed without any practical problems. Therefore, it is completely different from the conventional control system in which differentiation is performed to stabilize.

In the embodiment of the present invention, the target position of the rolled material is set by the setter.
Although the case of giving the rolled material 11 has been described, the initial biting position of the rolled material 11 into the rolling mill is memorized so that it can be given as a control target, or the rolled material 11 can be set at an arbitrary position in the rolled material width direction. It can be carried out even if the setting is changed to pass, if the rolled material is a cold rolled material, the present invention can be applied by installing a light source above or below the rolled material, not limited to a four-high rolling mill. It can be applied to all types of rolling mills in which meandering is a problem, the control circuit can be configured by software using a computer instead of hardware, and a meandering detector is attached to both the inlet side and the outlet side of the rolling mill, It goes without saying that the control device of the present invention can be configured based on both signals, and that various changes can be made without departing from the scope of the present invention.

[Effect of the Invention] According to the meandering control device of the present invention, when the tail end of the rolled material slips through one rolling mill upstream, based on the slip-out signal,
Since the meandering control is performed by applying the differential gain to the constant rolling reduction signal, the meandering control of the rolled material tail end is performed without any problem even after slipping through the upstream rolling mill.

[Brief description of drawings]

FIG. 1 is an explanatory view of an embodiment of the meandering control device of the present invention, FIG. 2 is a detailed explanatory view of FIG. 1, and FIG. 3 is a differential gain applied when the tail end of the rolled material of FIG. 4 is a graph showing the relationship between the time and the amount of meandering in the case of rolling, FIG. 4 is an explanatory view showing the rolled material approaching one end of the roll, FIG. 5 is its plan view, FIG. 6 and FIG. The figure is an explanatory view of the reason why meandering occurs after the tail end of the rolled material has slipped off, Fig. 8 is an explanatory view of the region where stable meandering control can be performed when the tension of the rolled material is ignored, and Fig. 9 is the rolled material tail. 7 is a graph showing a relationship between time and a meandering amount when the meandering control is performed without applying a differential gain when the trailing edge is missing. In the figure, 1a is an upstream rolling mill, 1b is a downstream rolling mill, 2 is a load detector, 3 and 4 are work rolls, 9 and 10 are hydraulic cylinders, and 13 and 1
4 is a servo valve, 15 and 16 are displacement detectors, 17 and 18 are addition amplifiers, 19a and 19b are end position detectors, 20 is a calculator, 21 is a setter, 22 is a comparison calculator, and 24 is a meandering control. A controller, 25 is a summing amplifier, 28 is a controller body, 29 is a differentiator, and 31 is a changeover switch.

Front page continuation (72) Shinichiro Taniguchi, 1850 Minato, Wakayama, Wakayama Sumitomo Metal Industries, Ltd., Wakayama Steel Works (72) Inventor, Hiroaki Miura, 1850, Minato, Wakayama, Wakayama Sumitomo Metal Industries, Ltd. (56) References JP-A-58-68413 (JP, A)

Claims (1)

[Claims] 1. A tandem rolling mill, comprising an end position detector for detecting the end position of the rolled material width, which is provided on at least one of the working side and the driving side of the required rolling mill. A meandering amount calculation device that calculates a meandering amount by calculating a difference between output signals of the end position detector, and a comparison calculation device that compares and calculates an output signal of the meandering amount calculation device and a target position signal of a rolled material, When the rolled material is bitten by both the required rolling mill and the rolling mill one upstream of the required rolling mill, a steady-state rolling reduction correction signal is obtained from the signal obtained by the comparison operation device. When the tail end of the rolled material passes through the rolling mill on the upstream side of the rolling mill, the differential gain is applied to the reduction correction signal based on the trailing slip signal to obtain and output the reduction correction signal at the time of slipping. Equipped with a control adjustment device Ri said desired rolling mill of the work side, meandering control device being characterized in that so as to change the roll gap on the drive side.