JPH0256965B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a tension control device for rolled material between stands, and particularly in a rolling facility comprising a plurality of rolling mills and a winder for rolled material. This invention relates to a tension control device for a rolled material suitable for reducing the effect on an upstream rolling stand of tension fluctuations that occur in a rolled material between stands after it straddles the stands until it is wound up by a winder. .

[Technical background of the invention]

Recent inter-stand tension control has replaced the conventional method of controlling the tension by directly pressing the free roll against the rolled material between the stands, such as air louver or electric louver, by mechanically fixing the tension by combining the free roll and a load cell. Many methods are being adopted that detect and control tension based on shape. Compared to the former conventional method, this method is lower in cost and has a faster response time.
This is because it has many advantages such as easy maintenance.

FIG. 1 is an explanatory diagram showing the principle of tension detection using a tension bar that is a combination of this free roll and a load cell. In the configuration shown in FIG. 1, the rolled material 34 generates tension between the two stands STD1 and STD2, and this tension is transmitted from the free roll 1 in contact with the rolled material 34 to the load cell 2 via a bearing.
transmitted to and detected.

In other words, there are two stands for rolling the rolled material 34.
When a speed difference occurs between STD1 and STD2, the free roll 1 is held down by the tension generated in the rolled material 34, and a load is generated in the vertical direction. This vertical load is transmitted from the free roll 1 to the load cell 2 via the bearing 3. In this case, the value obtained by subtracting the load of the free roll 1 and its bearing 3 from the total load detected by the load cell 2 becomes the load generated by the tension component. By calculating backward from the angle of the rolled material 34 based on the load detected in this manner, the value of the tension occurring in the rolled material 34 can be determined.

Tension control of rolled material between stands basically involves controlling the tension generated in the rolled material due to the speed difference between two stands by correcting the speed of one stand by an amount corresponding to the tension deviation. It is done by.

FIG. 2 shows a block diagram of a conventional tension control device for rolling material between stands. In this configuration, the load detected by the load cell 2 is converted into a tension signal 5 by the load tension conversion circuit 4. The tension control circuit 12 receives the tension signal 5 and the tension reference signal 11 set by the tension setting device 10.
A tension deviation is calculated from the above, and a speed correction amount signal 13 corresponding to the amount of this deviation is output. Speed reference circuit 1
4 combines the speed reference signal 16 set by the speed reference setter 15 and the speed correction amount signal 13 which is the output of the tension control circuit 12, and the Leonard device 1
The speed control reference signal 17 to the 8 is output. In addition,
The Leonard device 18 is a stand drive transmission 1
This device controls the speed of the stand driving electric motor 19 using this speed control reference signal 16 and a speed feedback signal from the stand driving electric motor 19 (not shown).

Note that the specific configuration of the tension control circuit 12 is as follows.
This is as shown in the circuit configuration diagram in the figure. In the configuration shown in FIG. 3, the subtracter 6 outputs a tension deviation ΔT which is the difference between the tension reference signal 11 and the tension signal 5. The proportional controller 7 that receives the tension deviation △T inputs the tension deviation △
Outputs a proportional signal proportional to T. On the other hand, the integral controller 8 outputs an integral signal obtained by integrating the tension deviation ΔT. The adder 9 outputs a sum signal of the proportional signal that is the output of the proportional controller 7 and the integral signal that is the output of the integral controller 8. Furthermore, the proportional gain setter 21 sets the proportional gain of the proportional controller 7,
The integral gain setter 22 is for setting the integral gain of the integral controller 8.

FIG. 4 is a time chart showing the relationship between the tension and the speed correction amount in the configuration shown in FIG. 2, and shows the case where there is a variation in the tension. The operation of the tension control circuit 12 will be explained with reference to the figure. In addition,
FIG. 4a shows a factor diagram of the tension fluctuation that will occur in the rolled material 34, FIG. 4b shows the tension reference signal 11, and FIG. 4c shows the tension signal 5 after control. On the other hand, d in the figure is the tension deviation ΔT obtained from the tension reference signal 11 and the tension signal 5 by the subtractor 6. This tension deviation ΔT is input to the proportional controller 7 and the integral controller 8,
The respective output signals are added by an adder 9, and a speed correction amount signal 13 is obtained as a result. This speed correction amount signal 13 is the signal shown in FIG. 4e. The proportional gain of the proportional controller 7 and the integral gain of the integral controller 8 are set so that a stable and quick control response can be obtained as a tension control system. The reason why the tension signal 5 shown in Fig. 4c is less affected by tension fluctuations is that the control gain is set to obtain a fast control response, and the speed correction of the stand in response to tension fluctuations is shown in Fig. 4e. This is due to the fact that this is done promptly. In other words, the tension fluctuation factor shown in Figure 4a should be expressed in Figure 4c, but by correcting the speed of the upstream stand STD1 using the speed correction amount signal 13 shown in Figure 4e, the tension fluctuation can be reduced. It becomes possible to suppress the

[Background technology issue]

The operation of the conventional tension control device has been described above, but the tension control itself is performed when the rolled material 34 is on a stand.
It has been implemented since the transition between STD1 and STD2. That is, in FIG. 1, tension control between the stands STD1 and STD2 is started from the time when the tip of the rolled material 34 is bitten into the stand STD2 on the downstream side. Therefore, the state of the rolled material 34 between the stands STD1 and STD2 is maintained even after the tip of the rolled material 34 is bitten by the stand STD2 until it is wound up by the winder, and even after it is wound up by the winder. Tension control will be performed similarly. however,
Until the rolled material 34 is wound up by the winder, the rolled material 34 on the downstream side of the stand STD2 on the downstream side is not subjected to forward tension due to the winder, so that the rolled material 34 and the rolled material 34 in the stand STD2 are Slips tend to occur between the two. This slip causes tension fluctuations in the material rolled between the stands, but in this case, the amount of the fluctuations and the frequency of occurrence are relatively large. If tension control is performed on the amount and frequency of this large tension variation, the speed of the upstream stand STD1 will vary greatly, which is not desirable from the standpoint of ensuring the quality of the rolled material 34. .

[Purpose of the invention]

Therefore, in view of the problems of the prior art described above, an object of the present invention is to make the control response of the tension control circuit slower than the original setting value from the time the rolled material passes through the final stand until it is wound up by the winder, By returning the control response time to the original value after the start of winding of the rolled material, it is possible to perform rolling without degrading the quality of the rolled material due to the downstream stand before winding the tip of the rolled material. An object of the present invention is to provide a tension control device for smoothed rolled material between stands.

[Summary of the invention]

In order to achieve the above object, the present invention provides a continuous rolling facility equipped with a plurality of rolling stands that continuously roll rolled material, and a winder that winds up the rolled material derived from the final rolling stand. a tension detection means for detecting the tension of the rolled material between the final rolling stand and an upstream rolling stand; a tension setting means for setting the tension of the rolled material; a tension reference of the tension setting means; and the tension. tension control means for controlling the speed of the upstream rolling stand so that the difference from the tension detection value of the detection means becomes zero; and winding tension detection means for detecting that the winding machine has entered tension control. , the control gain of the tension control means is maintained at a level that does not cause slips in the rolled material until the winding tension detection means detects the start of tension control, and the winding tension detection means detects the start of tension control. and control gain switching means for switching the control gain of the tension control means to a level premised on the existence of the forward tension generated by the winder.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 5 shows a block diagram of a tension control device for rolled material between stands according to an embodiment of the present invention.
The difference from the conventional equipment shown in Fig. 2 is that the rolled material 3
Stand STD2 where the tip of 4 is the final stand
After passing through the rolling material 34, the tip position detector 24 detects whether the rolled material 34 is yet to be wound by the winding machine 25 and outputs a gain switching signal 26 to the control gain switching circuit 29. This is because a proportional gain setter 20 for setting the proportional gain when the tip of the winder is before winding by the winder 25 and an integral gain setter 23 for setting the integral gain are added.
Note that the proportional gain setter 21 outputs a proportional gain signal 31 during normal operation, and the integral gain setter 22 outputs an integral gain 32 during normal operation. On the other hand, the proportional gain setting device 20 outputs a proportional gain signal 30 at the tip of the rolled material 34 before winding, and the integral gain setting device 23 outputs the proportional gain signal 30 at the tip of the rolled material 34 before winding. An integral gain signal 33 is output. Control gain switching circuit 2
9 selects one of the proportional gain signals 21 and 20 and the integral gain signal 3 based on the gain switching signal 26.
2 or 33 to output a proportional gain signal 27 and an integral gain signal 28 and give them to the tension control circuit 12.

FIG. 6 is a time chart showing changes in the tension and speed correction amount signals, etc. in the configuration of FIG. The figure c shows the tension reference signal 11.
shows. 6d shows the tension after control, e shows the tension deviation signal, and f shows the speed correction amount signal. The reason why this speed correction amount signal does not show a sudden change as shown in FIG.
It can be seen that the speed changes less.

Now, the basis for changing the control gain in the tension control circuit 12 will be explained. Tension control circuit 12
Since proportional-integral control is performed in this case, the transfer function is 1+T ₂ ·S/T ₁ ·S=1/T ₁ ·S+T ₂ /T ₁ (1). In equation (1), the first term on the right side is the integral part, and the second term is the proportional part. Therefore, the integral gain setter 22 and 23 set 1/T ₁ in the above equation, and the proportional gain setter In 20 and 21, T ₂ /T ₁ of the above formula is arranged. In this case, T ₂ only or T ₁ and T ₂
By changing the set value of , the transfer function of the tension control circuit 12 can be changed, so the control response of the tension control system can be changed.

Note that the tip detection signal of the rolled material 34, which is the output signal of the tip position detector 24, that is, the control gain switching signal 26, is set at the start of winding after the rolled material has passed the stand STD2. As a method, there are methods such as finding the rise of the current in the winding motor, or finding it by controlling the tension of the winding machine.

Next, specific operations in the configuration shown in FIG. 5 will be explained.

First, after the rolled material 34 is caught in the stand STD2 which is the final stand, until it is wound up by the winder 25, the control gain switching signal 26 is set by the tip detector 24 of the rolled material 34. has been done. When the control gain switching signal 26 is set, the control gain switching circuit 29 converts the proportional gain signal 30 from the proportional gain setter 20 and the integral gain signal 33 from the integral gain setter 23 into a proportional gain signal 27 and an integral signal, respectively. gain signal 2
8 to the tension control circuit 12. and,
After the rolled material 34 is wound up by the winder 25 and the control gain switching signal 26 which is the output of the tip detector 24 is reset, the proportional gain signal 31 from the proportional gain setting device 21 and the integral gain setting device 22
The integral gain signal 32 is outputted to the tension control circuit 12 as a proportional gain signal 27 and an integral gain signal 28, respectively. The time at which the tip detection signal of the rolled material 34, that is, the control gain switching signal 26 is reset, is the winding start time, and is shown in FIG.
It is _t20 . That is, the control gain switching circuit 29 switches the control gain of the tension control circuit 12 before and after time _t20 .

That is, the proportional gain setter 20 and the integral gain setter 23 generate a proportional gain signal 30 and an integral gain signal 33 that lower the control gain of the tension control circuit 12. The device 22 generates the same proportional gain signal 21 and integral gain signal 32 during normal operation, that is, when set in the configuration shown in FIG.

For this reason, the control gain of the tension control circuit 12 until the tip of the rolled material 34 is wound up by the winding machine 25 is kept low, so even if a tension fluctuation factor occurs as shown in FIG. 6a, As shown in FIG. 6f, no sudden change occurs in the speed correction signal, and therefore the speed of the upstream stand STD1 does not change significantly.

On the other hand, after the tip of the rolled material 34 is wound up by the winder 25, that is, after time _t20 , the control gain switch 29 switches and the system has the same configuration as that shown in FIG. As shown in the figure, tension fluctuations are suppressed to a minimum due to the fast control response.

Note that switching the tension control gain, that is, lowering the control gain, delays the control response of the tension control system, and the tension that changes within a shorter time than this control response is ignored. Therefore, the speed correction of the upstream stand is reduced due to the tension that changes within this short period of time.
The influence on other control systems is reduced. However, it goes without saying that the response time of this tension control system cannot be delayed indefinitely, but is set in consideration of the allowable amount of variation in tension on the rolled material.

By the way, the configuration of the tip detector 24 shown in FIG. 5 can be of various types including contact type and non-contact type, but it is not possible to reliably switch the control gain switching circuit 29 at an appropriate timing. Any format can be applied.

〔Effect of the invention〕

As described above, according to the present invention, by slowing down the control response of the tension control system from when the rolled material passes through the final stand until it is wound up by the winder, Therefore, it is possible to obtain an effective tension control device for a rolled material between stands, which reduces unnecessary influence on other stands due to tension fluctuations caused by the tension fluctuation.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the principle of tension detection by a tension bar, Fig. 2 is a block diagram of a conventional tension control device for rolled material between stands, Fig. 3 is a circuit diagram of the tension control circuit shown in Fig. 2, FIG. 4 is a time chart showing the relationship between tension and speed correction amount in the configuration of FIG. 2, FIG. 5 is a block diagram of a tension control device for rolled material between stands according to an embodiment of the present invention, and FIG.
The figure is a time chart showing the relationship between tension and speed correction amount in the configuration of FIG. 5. 1...Free roll, 2...Load cell, 4...Load tension conversion circuit, 6...Subtractor, 7...Proportional controller, 8
... Integral controller, 9... Adder, 10... Tension reference setter, 12... Tension control circuit, 13... Speed correction amount signal, 14... Speed reference circuit, 15... Speed reference setter, 18... Leonard device, 19... Rolling mill drive electric motor, 20, 21...proportional control gain setting device, 2
2, 23... Integral control gain setter, 24... Tip position detector, 29... Control gain switching circuit, 34... Rolled material, STD1, STD2... Rolling mill stand.

Claims (1)

[Claims] 1. In a continuous rolling facility equipped with a plurality of rolling stands that continuously roll rolled material and a winder that winds up the rolled material derived from the final rolling stand, the final rolling stand and the rolling mills upstream from the final rolling stand a tension detection means for detecting the tension of the rolled material between the stand; a tension setting means for setting the tension of the rolled material; and a difference between the tension reference of the tension setting means and the tension detection value of the tension detection means. a tension control means for controlling the speed of the upstream rolling stand so that the speed becomes zero; a winding tension detection means for detecting that the winding machine enters tension control; and the winding tension detection means controls the tension control. The control gain of the tension control means is maintained at a level that does not cause slip in the rolled material until the start of tension control is detected, and when the winding tension detection means detects the start of tension control, the control gain of the tension control means is maintained at a level that does not cause slip in the rolled material. and control gain switching means for switching the control gain to a level based on the presence of forward tension generated by the winder.