JPH0366407A - Control device for rate of elongation - Google Patents

Abstract

PURPOSE:To prevent a delayed response and to make a quick convergence to the set value of the rate of elongation by giving the control object with the rate of change of a control output for deviation in the case of the deviation of the measured value and set value of the rate of elongation of a material exceeding a constant value and holding the control output as well in the case of the deviation being constant. CONSTITUTION:When a large variation in working conditions of the changing time of a steel sheet, etc,. is caused and the deviation in the rate of elongation becomes more than a constant value exceeding a dead zone D, it is detected by a dead zone detecting means 10. The rate of change of the control output is then outputted while changing it by an adjusting means 11 with the rate of change of a constant control output or in accordance with the size of the deviation of the rate of elongation, added by the output of a proportional plus integral control device 7 and an adder 12 and a rolling reduction adjusting mechanism 9 is operated via a rolling reduction control device 8. The adjusting means 11 has the function holding the control output at the time when the deviation of the rate of elongation comes in the dead zone.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an elongation rate control device in a process involving elongation processing such as a temper rolling mill, a skin pass rolling mill, or a tension leveler.

[Conventional technology]

One manufacturing process for ensuring the tensile strength of steel plates and the like is a process of skin pass rolling, temper rolling, or tension leveling of the annealed steel plate.

In this process, for example, the rate of change in plate thickness, that is, the elongation rate, between the entrance and exit sides of the rolling mill is kept constant to ensure uniform quality.

By the way, this elongation rate is accurately expressed by the formula % (%)), but for convenience, it is expressed by the formula ε = (V-v')/v (1) (V: entry side steel plate speed, V; It is calculated as the exit steel plate speed). In other words, it is common to simultaneously measure the board speed on the crowded side and calculate the elongation rate from the rate of change.

FIG. 5 is a schematic diagram showing an outline of a conventional elongation rate control device. In the figure, 1 is a rolling mill that rolls a steel plate 2. The elongation rate by the rolling mill 1 is determined by the elongation calculation device 5 using the above formula (1) from the difference between the inlet plate speed and the outlet plate speed measured by the speed detection touch roll 3.3 and the speed sensor 4.4. Calculated from.

The actual value of the elongation rate is compared with the elongated amniotic membrane constant value by a comparator 6, the deviation of the elongation rate is calculated, and the deviation signal is input to the proportional integral (PI) control device 7 to perform proportional and integral operations. A loop is formed in which the result is input to the roll-down control device 8, the control signal is inputted to the roll-down adjustment mechanism 9, and the roll-down or load is controlled.

Through this loop, if the elongation rate changes, the reduction or load is adjusted by the PI control loop, and the elongation rate is controlled to match the set elongation rate value. In the case of a tension leveler, the basic configuration is the same except that the tension or speed is modified.

[Problem to be solved by the invention]

However, the conventional device described above has the following problems.

Controlling the elongation rate is not a problem when there are no large changes in conditions, such as when using the same steel type, or when the changes are small, but for example, in the case of a jingle stand rolling mill, there is an opportunity to change the coil, or in the case of a continuous line, it is necessary to control the elongation rate when welding steel plates. The dimensions of the steel plate (width, thickness) or the properties of the steel plate (material, annealing conditions, etc.) change rapidly before and after the process. At each time of this change, the pressure is reduced (load)
Alternatively, it may be necessary to modify the tension (speed). If this correction is delayed, the elongation rate will be out of the allowable range, causing poor strength of the product.

However, in the conventional control method that applies proportional integration to the elongation rate deviation and outputs the control output, the control output is limited in order to ensure control stability, and it is difficult to follow the rapid elongation processing conditions described above. I can't do it.

In addition, the proportional gain and integral gain of PI control are such that their proper values should be changed depending on the characteristics of the steel plate and other operating conditions. However, since it is relatively difficult to always provide an appropriate gain depending on the characteristics of the steel sheet and other operating conditions, a low gain is usually provided to prevent the control system from becoming unstable. For this reason, when there is a rapid change in processing conditions, such as when the steel plate changes, the elongation rate changes significantly and it takes time to converge. If the convergence time is long, the strength of the rolled material during that time will be poor due to a response delay, and that portion will have to be cut down, which is a factor in reducing yield.

Therefore, the main purpose of the present invention is to quickly eliminate deviations in the elongation rate due to response delays and to quickly converge the elongation rate to the set elongation rate when there is a major change in condition such as the change in steel plate. The purpose of this invention is to provide an elongation rate control device that can control the elongation rate.

[Means to solve the problem]

In order to solve the above problems, the present invention measures the elongation rate of the material between the input side and the output side of the stretching process, and calculates the elongation rate based on the deviation between the measured elongation rate and the preset elongation rate. , in a device that controls the elongation rate of a material to be constant by performing feedback control on a controlled object; dead zone detection means for detecting that the deviation exceeds a certain value; and under a condition that the deviation exceeds a certain value; This problem can be solved by providing an adjusting means that applies a certain rate of change of the control output to the controlled object with respect to the elongation rate deviation and maintains the control output when the elongation rate deviation is within a constant value range.

On the other hand, more preferably, the proportional integral feedback control is performed based on the deviation between the actually measured elongation rate of the material and the preset set elongation rate between the input side and the output side of the stretching process. an integral control device; a dead zone detection means for detecting when the deviation exceeds a deviation value large enough to cause a response delay under control by the proportional-integral control device; an adjusting means for applying a change rate of a control output to a controlled object with respect to a rate deviation and holding the control output when the elongation rate deviation is within a constant value range; and an output from the proportional-integral control device and an output from the adjusting means. This can be solved by adding the above and applying it to the controlled object and providing an adder.

Here, the rate of change of the control output refers to the rate of change over time (11111/sec) of the control output, e.g., rolling reduction rate.

[For production]

In the present invention, in consideration of the fact that conventional proportional-integral control devices cause a response delay when there is a large change in machining conditions,
Under the condition that the deviation exceeds a certain value, the control output for the elongation rate deviation is applied to the controlled object at a certain rate of change by the adjusting means. Therefore, when such a supplementary adjustment system for rapid adjustment and a proportional-integral control device are used together, the control speed can be adjusted by adding the control output by the adjustment means to the control output by the proportional-integral control. can be increased.

Therefore, response delay can be prevented as much as possible, and the strength of the material in the longitudinal direction can be made uniform.

[Specific structure of the invention]

The present invention will be explained in more detail below with reference to the drawings.

FIG. 1 is a flowchart showing the control device according to the present invention. In the figure, the difference from the conventional device (see FIG. 5) is that the deviation is so large that control by the proportional-integral control device 7 causes a response delay. dead zone detection means 10 for detecting that the deviation value has been exceeded; adjustment means 11 for outputting a control output for the elongation rate deviation at a certain ratio under conditions in which the deviation exceeds the large deviation value; and the proportional-integral control. An adder 12 is added for adding the output from the device 7 and the output from the adjusting means 11 and applying the result to the controlled object.

In other words, when a large change in machining conditions occurs, such as at a change in the steel plate, and the elongation rate deviation exceeds a certain value exceeding the dead zone, as shown in (a) or (bl) in Fig. 2, the dead zone detection means 10 detects the Detecting this, the adjustment means 11 adjusts the control output at a constant rate of change (in case (a)) or while changing the rate of change in control output according to the size of the elongation rate deviation (in case (b)). ) is outputted and added by an adder 12 to the output of the proportional-integral control device 7, and the reduction adjustment mechanism 9 is operated via the reduction control device 8. It has a function to hold the control output when the rate deviation falls within the dead zone.

Through the series of operations described above, it is possible to achieve faster convergence of the growth rate without response delay than in the case of conventional proportional-integral control only.

Note that when there are few changes in processing conditions, such as when the steel plate changes, proportional-integral control is performed only by the proportional-integral control device 7 without operating the dead zone detection means 10, and therefore without causing an output from the adjusting means 11. You can also do that. If necessary, in the present invention, it is also possible to omit the proportional-integral control device 7 and perform control using only the dead zone detection means 10 and the adjustment means 11. In this case, it is preferable to make the width of the dead zone narrower than in the above example.

In such an apparatus, the rate of change in the output from the adjusting means 11 can be made variable depending on the magnitude of the elongation rate deviation, as shown in FIG. 2+b). As a result, when the deviation is large, the rate of change can be made larger to speed up convergence, and when the deviation is small, the rate of change can be made smaller to reduce overshoot. Further, the rate of change and the width of the dead zone can be appropriately set depending on the steel type, line speed, etc.

For example, the rate of change should be determined based on the lifting speed limit of the rolling device, or the lifting speed limit that takes into account the effect on rolling stability, that is, squeezing the material directly under the rolls, rather than considering control stability. I can do it.

Regarding the dead zone, under the conditions of the above rate of change, the polarity of the control deviation is reversed, due to changes in the reduction due to inertia and changes in the elongation rate after the elongation rate deviation reaches the dead zone and the control is turned off. It is important to select such that no overshoot (overshoot) occurs. Therefore, an appropriate dead band width setting value is preferably determined in relation to the magnitude of the rate of change and the response of the reduction control system.

Also, as mentioned above, when changing the magnitude of the rate of change according to the elongation rate deviation, the larger the deviation, the more serious the change, and when the dead band is detected and the control is turned off, Just adjust it so that it doesn't go too far. This case has the advantage that the dead zone width can be made smaller.

〔Example〕

Next, the effects of the present invention will be clarified through examples.

In this example, the annealing conditions, etc. are the same as those of the prior art, and the thickness of the steel material is changed from 0.6 mm to 0.5 mm. Figure 3 shows the results of rolling performed using the device of the present invention and the conventional device. and shown in FIG. That is, Fig. 3 (al
, (b) and tel indicate the case using the conventional device, and FIG.

First of all, as shown in Figure 3, the thickness of the steel material used to be 0.6.
Even if the 0.5 rule is changed from
The change in the load value (load value) was extremely gradual, and as a result, as shown in FIG.

On the other hand, according to the present invention, the added adjustment correction amount is given to the controlled object in response to a large elongation rate deviation by the dead zone detection means and the adjustment means, so that the elongation rate is adjusted to the set elongation as shown in FIG. 4 (al). The convergence time to reach the desired rate was extremely short (4 seconds).

〔Effect of the invention〕

As described above, according to the present invention, when there is a large state change such as a change in the steel plate, deviations in the elongation rate due to response delay can be resolved in a short time, and the elongation rate can quickly converge to the set elongation rate. I can do it.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the basic configuration of the device of the present invention, FIGS. 2(a) and 2(b) are correlation diagrams of elongation rate deviation and control output due to the proportional-integral control device and the adjusting means, respectively, and FIG.
Figures (a) to fcl are graphs showing control modes and results by the conventional device, Figures 4 (a) to (C) are graphs showing control modes and results by the device of the present invention, and Figure 5 is the basic configuration of the conventional device. It is a flowchart which shows. DESCRIPTION OF SYMBOLS 1... Rolling machine, 2... Steel material, 3... Speed detection roll, 4... Speed sensor 5... Elongation rate measuring device,
7... Proportional-integral control device, 8... Drop-down control device, 9
... Pressure adjustment mechanism, 10... Dead zone detector, 10.
...Adjustment means. Fig. 1 Fig. 2 (α) (b) Fig. 3 (α) (b) fc) ('l!, 禾) Fig.

Claims (2)

[Claims] (1) Measure the elongation rate of the material between the input and exit sides of the elongation process, and perform feedback control on the control target based on the deviation between the measured elongation rate and the preset elongation rate. In a device for controlling the elongation rate of a material to a constant value by: a dead zone detection means for detecting that the deviation exceeds a certain value; and a certain control output for the elongation rate deviation under the condition that the deviation exceeds a certain value. an elongation rate control device, characterized in that it is provided with an adjusting means for applying a change rate of . (2) A proportional-integral control device that performs feedback control using a proportional-integral method based on the deviation between the actually measured elongation rate of the material and the preset elongation rate between the input side and the output side of the elongation process. and dead zone detection means for detecting that the deviation exceeds a deviation value large enough to cause a response delay under control by a proportional-integral control device; an adjusting means that applies a certain rate of change of control output to the controlled object and maintains the control output when the elongation rate deviation is within a constant value range; and adding the output from the proportional-integral control device and the output from the adjusting means. 1. An elongation rate control device comprising: an adder in which the elongation rate is applied to a controlled object;