JPH0732023A - Method for controlling looper angle and tension by multiple periodic control of hot finishing mill - Google Patents

Abstract

PURPOSE:To attain stabilization and noninterference in the process of a finishing mill as well as the realization of a robustness and of a fault transferability by making the looper height and the control of a tension of a finishing mill each different period and making the looper angle and the tension between stands noninterfering. CONSTITUTION:As the result of performing a simulation by means of a noninterfering system between a looper angle and an inter stand tension by a multiple periodic control, a response at the time of impressing a step input in r1, r2 at t=0 is made fully noninterfering in spite of the actual presence of interfering items. The entire system is also fully stabilized. Thus, by providing controllers with a different period, the entire system is stabilized through the stabilization of a system, and the noninterference and the robustness are also realized. Moreover, even in the event of the occurrence of failure in any controller, other controllers are not influenced by that; A so-called fault transferability is realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a looper angle and tension control method for multi-cycle control of a hot finish rolling mill.

[0002]

2. Description of the Related Art Conventionally, in a rolling mill, a gauge meter type plate thickness control has been widely used as an automatic plate thickness control and has a high control efficiency. However, in recent years, such as deep-drawing ultra-low carbon steel, in hot finish rolling, the ratio of materials that are likely to cause plate thickness fluctuations may increase, so that the accuracy of plate thickness demanded by customers for rolling mills is further improved. It's getting tougher. On the other hand, steel manufacturers also need to improve yields, and the reality is that there is an urgent need to realize more advanced plate thickness control.
Therefore, it is empirically known that the strip thickness of the rolling mill can be changed by controlling the tension between stands. Finishing tandem rolling mills in the hot rolling process conventionally have loopers between stands. In the hot-rolled sheet thickness control, the tension between the stands greatly changes because the reduction control operates independently at each stand. This change is absorbed by the looper.

On the other hand, as disclosed in Japanese Patent Laid-Open No. 18922/1990, particularly in a hot rolling mill, the strip thickness control and the crown control by the bending operation do not interfere with each other.
The present invention relates to a control device that has a good control effect. Therefore, in response to the signals from the rolling force detector and the pressure sensor inside the bender, the influence of the rolling position operation amount on the plate thickness fluctuation and crown amount fluctuation, and the roll bending pressure operation amount on the plate thickness fluctuation and crown amount. The influence on the fluctuation is obtained respectively, the inverse matrix of the influence coefficient matrix of the control variable matrix formed by these coefficients and the operation variable matrix is obtained, and this is multiplied by the operation variable matrix to obtain a new operation variable matrix (Δs ^* △ There is provided a compensation calculation device for calculating r ^* ) and outputting it to the bending pressure operation amount calculation device as the reduction position operation amount of Δs ^* .

Further, FIG. 4 shows a conventional looper height and tension control system for a finish rolling mill. As shown in FIG.
In the tension and looper height control system, the interference term of and is r
_It is necessary to _{deinterfer 1} , ₁ , r ₂ and T _L1 , T _L2 . Corresponding with a gain of K _2, K ₃ for r _1, r ₂ Therefore, also for T _L1, T _L2 is Kf ₁₄ ~Kf
₁₆ , it is necessary to achieve decoupling at Kf _{24 to} Kf ₂₆ .

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
As in Japanese Patent No. 8922, it is known to perform so-called non-interference control in which the plate thickness control and the crown control by the bending operation do not interfere with each other but separate the mutual interference and cancel the interference. Further, as shown in FIG. 4, for example, in the looper height and tension control method in the rolling process, as a looper control method (i to i + 1), the inter-stand tension and the looper height are kept constant under any disturbance. The current of the looper torque motor and (i +
1) The stand roll speed is controlled simultaneously.
In such a two-input and two-output process, since the conventional process design is a method of configuring a multi-input / output controller with the same period, it is necessary to know the degree of internal interference of the process extremely accurately, and the required control is required. There is a problem that the characteristics cannot be realized.

[0006]

In order to solve these problems, as a result of intensive development by the inventors, as a result of setting the looper height and tension control of the finishing mill to different control cycles,
By stabilizing the subsystem, the entire system is stabilized, and decoupling and robustness are realized, and even if one of the controls fails, the other controls are not affected by it. An object is to provide a device having characteristics. The gist of the invention is that the control of the height and tension of the finish rolling mill looper is performed in different control cycles, and non-interference control of the looper angle and the tension between the stands is performed. It is in a looper angle and tension control method by periodic control.

The present invention will be described in detail below with reference to the drawings. FIG. 1 is an explanatory view showing a looper between stands in a finishing tandem rolling mill in a hot rolling process. This is because in the hot-rolled sheet thickness control, the roll gap control operates independently in each stand, so that a large change in the inter-stand tension is absorbed. Further, during rolling, the mass flow (plate thickness at each stand exit side × plate speed) must be constant, and control of this looper is the most important one. Reference symbol R ₁ is the looper arm length, R ₂ is the looper roll radius, H ₁ is the looper shaft and pass line height, θ
Is the looper set angle, L is the distance between the stands, and L ₁ (hereinafter referred to as LSTD) is the distance between the stand and the looper shaft. Further, the plate width B, the plate thickness h, and the unit tension t
Then, the tension can be represented by T = Bht.

FIG. 2 is a block diagram of the looper angle control loop and the main engine speed control loop. In the looper control method, the current of the looper torque motor and the (i + 1) stand roll speed are simultaneously controlled in order to keep the (i to i + 1) inter-stand tension and the looper height constant under any disturbance. This is a typical 2-input / 2-output process. As can be seen in FIG. 2, the subsystem from U ₁ to y ₁ is a unit, and the subsystem from U ₂ to y 1.
You can think of up to _{2 as} one unit. Therefore, considering the interference terms as β and α · E / LSTD, U ₁ → y
Stabilize subsystem ₁ and U ₂ → y with other controls
_It stabilizes the _second subsystem.

FIG. 3 shows a route by multi-cycle control according to the present invention.
With the par angle and tension non-interference control system configuration diagram between stands
is there. As a result of performing the simulation with the system of FIG.
r₁, R ₂Response when step input is applied at t = 0
The answer is that even though there is actually an
Has been interfered. Also, the whole system is completely stabilized
There is. However, UZ₁, UZ₂Are digital
This is the output value of the controller. Furthermore, robust stability
For the Young of the steel sheet that constitutes the interference term of the process
For the response when the rate E changes by 20%, the 3 ms system
Your cycle (U₁→ y₁) Looper height system has no effect
I understand that I have not received it. In addition, of 20ms control cycle
A little overshoot is seen in the mill speed system,
X₆Because the Young's modulus E is included in the loop
is there.

Next, regarding the characteristics of disturbance removal, looking at the behavior when disturbance is introduced into the looper motor and the mill speed,
When the disturbance T _L1 is applied to the looper motor (motor rated torque), the disturbance is removed by the 3 ms controller (loop system), and the mill speed system is not affected. Further, the characteristic of applying the disturbance T _L2 to the mill speed system (10% disturbance of control) is that the disturbance T _L2 → y ₂ → X ₂ → X ₃ → y when this control is not performed. _The impact response was worse due to the route of the interference term of ₃ , but the route of y ₂ → X ₂ → X ₃ is sufficiently stabilized. This effect greatly improved the interference (as judged by the y ₁ response).

Further, regarding the trans-transformation property, it is 3
ms controller, 20ms controller 0.4
See the effect when the output is set to 0 at the timing of sec
It At that time, set the looper controller (3 ms) to 0.4
When downed in sec, UUZ in 0.4 sec
₁= 0, but to show the operation of the controller
To UZ₁When you put out, the deviation is surely calculated.
I understand. y₁About X₁, X₂By the decrease of
It is gradually decreasing to 0. But the effect is y ₂In
Not appearing. In addition, the mill speed controller (20m
When s) is down for 0.4 sec, it has no effect.
I understand that I have not received it. However, the interference term from β is
Since it is gradually decreasing, UZ₁Output is 0.65se
It is slightly less in c. y₂Gradually decreases to 0
There is. For the time being, the controller internal variable rises after calculating the deviation.
You can see that From these simulations
By changing the control cycle, a system with multiple inputs and multiple outputs
It was found that it can be easily designed by dividing each subsystem.

In this way, by making the controllers have different periods, by stabilizing the subsystems, the whole system is stabilized, and decoupling and robustness are realized, and any controller Even if a failure occurs in the other controller, other controllers were able to achieve the so-called fault tolerance, which is not affected by it.

[0013]

As described above, according to the present invention, it is possible to stabilize and deinteract the process of a finish rolling mill, to realize robustness and to achieve a full-fault transducing effect. Is.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a looper between stands in a finishing tandem rolling mill in a hot rolling process,

FIG. 2 is a block diagram of a looper angle control loop and a main engine speed control loop,

FIG. 3 is a configuration diagram of a looper angle and tension non-interference control system between stands by multi-cycle control according to the present invention,

FIG. 4 is a control system configuration diagram for a conventional finish rolling mill looper height and tension control system.

[Explanation of symbols]

R ₁ Looper arm length R ₂ Looper roll radius H ₁ Looper shaft and pass line height θ Looper setting angle L Distance between stands L ₁ Distance between stand and looper shaft

Claims (1)

[Claims] 1. A looper angle by multi-cycle control of a hot finish rolling mill, wherein the looper height and tension of the finish rolling mill are controlled in different cycles, and the looper angle and the tension between stands are controlled without interference. And tension control method