JPH0622726B2 - Loop control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention forms a loop between rolling mills in a hot rolling mill of a steel plant and detects this with a loop height detector to determine the loop height. The present invention relates to a loop control device aiming to maintain the position (target height).

[Conventional technology]

FIG. 2 is a diagram of a conventional loop control device shown in JP-A-57-130712. The rolling mill on the upstream side in FIG.
(1) and the material to be rolled that passes through the rolling mill (2) on the downstream side and is rolled in the direction of the arrow (hereinafter, simply referred to as material) (3) is kicked out by a kick roll (2A) and looped later. A material loop is formed between the rolling mills (1) and (2) in synchronization with the control signal. The material position detector (4) inputs an electric signal proportional to the position of this loop to the feedback loop length calculation circuit (6).
On the other hand, the loop position set by the loop position setter (5) is the target value of the loop length of the material to be stored between the rolling mills (1) and (2) in the target loop length calculation circuit (7). The output from the above feedback loop length calculation circuit (6) and the subtraction circuit
Subtracted by (13), the speed correction circuit (1
Entered in 4). The speed correction circuit (14) is the subtraction circuit (13)
Output and the speed reference signal V _REF of the rolling mill (1) are subtracted and output to the motor drive circuit (15). The rolling mill (1) is connected to an electric motor (16) driven by the output of the drive circuit (15) to control the speed.

The contact point (20) is turned on by interlocking with the kick roll (2A), and the off operation is performed after the kick roll (2A) descends and the material loop position returns to the zero position, that is, the loop amount returns to zero. It has become.

Next, the operation will be described based on the above configuration. Rolling mill
Rolling mill with the tip of material (3) rolled in (1) and (2) downstream
After passing through (2), the kick roll (2A) is actuated in the direction of forming a loop and, at the same time, the contact (20) is turned on. If the loop target position Hr is set in advance in the loop position setter (5), the loop position detected by the material position detector (4) will be the moment when the contact (20) turns ON. Since it is the zero position at, the output from the feedback loop length calculation circuit (6)
lf is from equation (1) Loop length target value l _r outputted by next equal to zero whereas the target loop length calculating circuit (7) than (2) Since it is a value determined by the above Hr, Δl = lr-lf = lr at the timing of turning on the above scroll (2A),
At the timing when the contact (20) is turned on, the signal lr is input to the speed correction circuit (14). I.e. kitstrol (2A)
There actuated simultaneously rolling mill (1), (2) correction signal necessary for forming a material loop at the target loop position between v ₁ = k ₁ × l
_r is given to the rolling mill (1) through the speed correction circuit (14), the electric motor drive circuit (15), and the electric motor (16), and the kick roll (2
A) interlocks with the action of kicking out the material (3) to form a loop. When a loop is formed by this operation, the position of the peak point of the loop is detected by the material position detector (5), and the detection signal is sent to the feedback loop length calculation circuit (12).
It is input as a signal called Hf It is calculated as the loop length of the material stored between rolling mills (1) and (2) by the following approximate calculation. After that, the loop control operates so that Δl = l _r −l _f is always 0, and the correction signal for this is sent to the electric motor (16) connected to the rolling mill on the downstream side as a speed control signal (speed correction circuit ( 14) Motor drive circuit (1
5) to give l _r −l _f or Hr = Hf
It operates in an attempt to keep it in a position that satisfies the condition of. This correction signal can also be sent upstream.

[Problems to be solved by the invention]

Since the conventional loop control device adds the correction output of the loop control to either the upstream or downstream rolling mill as described above,
The correction output may become excessive, and especially when outputting the correction output to the upstream side, the rolling output on the upstream side outputs the correction output while the material is being bitten in.Therefore, if the control gain is increased, A large control gain cannot be obtained because it may cause a disturbance to some other loop control or adversely affect the material. Therefore, there was a problem that the corrected output was not suitable and the loop height could not be corrected and could continue to fluctuate. That is, in the case where the corrected output is made to flow upstream, if the pass schedules (speed balance) of two adjacent rolling stands do not match,
In order to match the pass schedule and make the loop height constant with the target value, it is necessary to output a corrected output larger than the start of control, which causes a problem that the speed fluctuation on the upstream side becomes large.

The present invention has been made to solve the above problems, and even if the pass schedules of two adjacent rolling stands are different from each other, the pass schedules are matched at an earlier stage to form a stable loop, and the upstream is improved. The purpose is to prevent disturbance to the loop control on the side.

[Means for solving problems]

The loop control device according to the present invention, based on the amount of deviation between the loop height detection value detected by the loop height detector and the preset loop height target value, outputs a correction output for correcting the deviation. First and second calculators for calculating and outputting the respective rolling mills on the upstream side and the downstream side are provided.

[Operation] According to the present invention, immediately after the material is caught in the downstream stand and the loop control is started, the second arithmetic unit that outputs the speed correction output to the downstream rolling mill is operated, and this speed correction output is held at a certain timing. However, this time, the first computing unit that outputs the speed correction output to the upstream rolling mill is operated.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, (1) is an i-1 stand (rolling mill), and (2) is an i stand, and a loop is formed between them. (8) is the rolled material. The loop height of this material (3) is detected by the loop height detector (4), and the height is converted into the length by the function generator (6). On the other hand, if the target loop height is set by the loop height setter (5), this is also converted to length by the function generator (7), and the output of the function generator (6) and the function generator
The deviation of the output of (7) is input to the first computing unit (8) and the second computing unit (9), respectively, where proportional control (P control) or proportional integral control (PI control) is performed, and the corrected output is First calculator
In the case of (8), the speed controller of the i-1 stand (upstream side)
(12), and in the case of the output of the second computing unit (9), it is output to the speed controller (13) of the i-stand (downstream side).

Then, (14) is the upstream successor circuit of the first computing unit (8), and the sum of the modified output of the downstream loop control and the modified output of its own loop control (the output of the first computing unit (8)) stands on the upstream side. It is a circuit that flows to.

Next, the operation of this embodiment will be described based on the above configuration. Consider, for example, the case where the material (8) bites sequentially from the first stand and then bites into the i stand to form a loop. At this time, the material tip is located between the i stand and the i + 1 stand. It is in. At this time, the calculation by the second calculator (9) is started in order to match the loop height with the target value. (At this time, the first computing unit (8) is still held or reset.) As a result, the corrected output from the second computing unit (9) is input to the i-stand speed controller, and the i-stand rolling roll Motor speed changes. At this time, even if the material is bitten from the first stand to the i-stand, the speed fluctuation does not affect the entire material because it is only the i-stand. I when the loop height matches the target value
It means that the speed balance of -1 stand and i stand is matched. At this time, the control gain of the second arithmetic unit (9) can be increased within the range where loop height control does not hunt. Therefore, as a matter of course, even if the speed between the upstream and downstream stands is unbalanced at first, the balance can be quickly achieved. Further, the calculation output of the second calculator (9) is held at the timing when the tip of the material bites into the i + 1 stand.

When the tip of the material bites into the i + 1 stand, the calculation operation of the first calculator (8) is started this time, and the known loop control is performed.

The corrected output output from the first computing unit (8) is output to the speed control device (12) of the i-1 stand and is also sent to the upstream stand side by the upstream successor circuit (14). At this time, if the material is bitten from the 1st stand to the i + 1st stand, the upstream successive circuit (14) outputs all the corrected output of the first computing unit (8) from the 1st stand to the i-1st stand. Become. When there is another loop control device upstream, the speed of the stand on the upstream side is corrected by the sum of the correction outputs of the plurality of loop control devices, so the control gain of the first computing unit (8) is It is necessary to set the gain so that the loop control does not hunt even if the loop control output is added. The hold and reset timings of the arithmetic output of the first arithmetic unit (8) are known loop control timings. However, even in this loop control, the speed imbalance is largely absorbed by the downstream side control in advance, so that the correction output does not need to be so large, and the loop height can be sufficiently controlled even with a low gain.

In the above embodiment, the stop timing of the second computing unit (9) is set to the i + 1 stand engagement, but this may be any time before the i + 1 stand engagement.

Further, in the present embodiment, the downstream control stand is only one stand (i stand), but it is also possible to control two stands at the same time.

However, at this time, the stop timing of the second computing unit (9) is i +
It should be up to one stand bite. Because i
It is possible to continue the calculation up to +2 stand biting,
The second computing unit after the tip of the material bites into the i + 1 stand
This is because the corrected output of (9) changes the speed of the two stands in which the material is bitten, which may cause speed imbalance between the i stand and the i + 1 stand.

〔The invention's effect〕

As described above, according to the present invention, there are two calculators for calculating the correction output of the loop height control, and the respective correction outputs are separately output to the upstream side and the downstream side, so that the speed imbalance between the stands is increased. Even when there is a problem, the loop control is stabilized quickly because of the control on the downstream side, and the control output to the upstream can be reduced.

Therefore, stable loop height control is possible even when the corrected output is made to flow to the upstream side.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the loop control device of the present invention, and FIG. 2 is a block diagram showing the configuration of a conventional loop control device. In the figure, (1) is an upstream rolling mill, (2) is a downstream rolling mill,
(3) is material, (4) is loop height detector, (5) is loop height setter, (8) is first calculator, (9) is second calculator, (12), (1
3) is a motor speed control device. In the drawings, the same reference numerals indicate the same or corresponding parts.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ken Okamoto 1-2 1-2 Wadazaki-cho, Hyogo-ku, Kobe-shi, Hyogo Mitsubishi Electric Corporation Control Works

Claims (1)

[Claims] 1. A loop of a material to be rolled is formed between rolling mills on an upstream side and a downstream side of a rolling line for continuously rolling a material to be rolled by a plurality of rolling mills, and a height of the loop is set to a loop height. The loop height is detected by a detector, the measured detection signal is compared with a target value signal set in advance by a loop height setting device, and the deviation signal is used as a speed correction signal for the rolling mill. In the loop control device configured to maintain the target value, a first computing device that computes a speed correction signal to be output to a motor speed control device for driving a rolling roll of an upstream rolling mill based on the deviation signal, A second calculator for calculating a speed correction signal to be output to a motor speed control device for driving the downstream side rolling rolls based on the deviation signal, and to the downstream side rolling machine from the second calculator at the start of loop control. The speed correction signal is output, and when the material to be rolled is conveyed to the next rolling mill on the downstream side, the speed correction signal is held for the downstream rolling mill, and at the same time, the upstream rolling mill from the first computing unit. A loop control device characterized in that a speed correction signal is switched to and output to correct the speed imbalance between the electric motors.