JPH04344815A - Tension controller - Google Patents

Abstract

PURPOSE:To obtain the product whose dimension accuracy is high by executing a stable rolling. CONSTITUTION:An arithmetic means 2a calculates the ratio of rolling torque and rolling pressure of the stand in use until the tip of a stock to be rolled is engaged in its own stand, and thereafter, engaged in an adjacent stand. A preserving means 6 preserves a predicted rolling schedule and a standard torque arm by the kind of a rolling stock. A comparing/selecting means 2c compares the ratio of the rolling torque with the rolling pressure calculated by the means 2a and the torque arm of the means 6, and excludes that of the deviation which exceeds a prescribed value from a sampling object. An arithmetic/storage means 2b executes the sampling of the ratio of the rolling torque and the rolling pressure from which the pressure which is unsuitable is eliminated, calculates a means value and stores it as a torque arm. A generated tension arithmetic circuit 3 calculates inter-stand tension at the time when the stock to be rolled is engaged with the next stand by using this torque. A tension arithmetic circuit 4 derives the deviation of this tension and a set value. A proportional-plus- integral circuit 5 calculates the tension deviation, and outputs a speed correction amount DELTAN.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a continuous rolling mill that continuously rolls steel plates, and in particular, a tension control device that controls the tension between stands using a torque arm that is a ratio of rolling torque to rolling pressure. Regarding.

0002

2. Description of the Related Art Controlling the tension acting on a rolled material in a continuous rolling mill to be constant or zero is an important factor in improving rolling dimensional accuracy.

FIG. 2 is a block diagram showing the configuration of a general tension control system that performs this type of control. In the figure, when a rolled material is rolled continuously in the order of stand i-1, stand i, and stand i+1, the rolling mills 8 of each stand are driven by electric motors 9 each having a speed control device 10. In this case, the speed control device 10 of each stand has a speed correction amount ΔN output from the tension control device 11 of its own stand based on the speed reference applied to the speed control device 10 of the front stand as seen in the moving direction of the rolled material. Added speed criteria are added. In addition, the tension control device 1 of each stand
1 calculates the speed correction amount ΔN using the so-called rear tension TB calculated by the tension control device 11 of the rear stand.

FIG. 3 shows the relationship between signal input and output of the tension control system, especially for the i-stand.
A speed correction amount ΔN is calculated based on the rotational speed N of the rolling mill detected by the speed detector 13, the armature current I of the motor 9 and the rear tension TB detected by the current detector 14, and the speed correction amount ΔN is sent to the speed control device 10. Add. The speed control device 10 controls the speed of the electric motor 9 based on a speed reference obtained by adding this speed correction amount ΔN to the speed reference of the front stand and the rotation speed N of the rolling mill detected by the speed detector 13.

FIG. 4 is a block diagram showing the detailed configuration of the tension control device 11, in which the rolling pressure P, the rotation speed N of the rolling mill,
Based on the armature current I of the motor 9, the motor output torque,
An acceleration/deceleration current removal device 1 that calculates the acceleration/deceleration torque and friction torque of the rolling mill including the electric motor, the motor output torque, the acceleration/deceleration torque, and the friction torque determined by the acceleration/deceleration current removal device 1, and the rear tension. The rolling torque Gm is calculated using
The torque arm calculation circuit 2a calculates the torque, and the ratio (Gm/P) between the rolling torque Gm and the rolling pressure P calculated by the torque arm calculation circuit 2a is sampled, and the average value of the obtained sampling values is taken to calculate the torque. arm a0
A torque arm lock-on circuit 2b that calculates and stores this, a generated tension calculation circuit 3 that calculates the inter-stand tension using this torque arm a0, and a set tension of a tension setting device (not shown) based on this inter-stand tension. The tension calculation circuit 4 calculates the deviation from the tension deviation, and the proportional integration circuit 5 performs proportional integration on this tension deviation and outputs the result.

Next, the operation of this tension control device will be explained.

When the material to be rolled is caught in the i-stand and rolling is started, the armature current I of the electric motor 9 increases rapidly. This current is detected by the current detector 14, and at the same time, the rolling pressure P is detected by the rolling pressure gauge 12, and further,
The rotational speed N of the rolling mill is detected by a speed detector 13 and input to the tension control device 11, respectively.

The armature current I input to the tension control device 11 includes not only the current for the rolling torque required for pure rolling, but also the acceleration/deceleration torque current required for accelerating and decelerating the rolling mill 8 and the electric motor 9, and the friction of the machine. Includes torque current. Therefore, in order to obtain the rolling torque Gm, the following equation must be calculated.

[0009]

[Math 1] however V: Armature voltage I: armature current N: Motor rotation speed R: Armature resistance K1 to K5: Constant It is.

Therefore, the acceleration/deceleration current removing device 1 is designed to operate during the period from when the tip of the material to be rolled is caught in the i-stand until just before it reaches the i+1 stand, that is, between the i-stand and the i-stand.
During the period when the tension generated in the rolled material between the +1 stands is zero, the motor output torque in the first term on the right side of equation (1) above, the acceleration/deceleration torque in the second term, and the friction torque in the third term are calculate.

The torque arm calculation circuit 2a calculates the rear tension T
Input B and calculate the torque due to the rear tension shown in the fourth term on the right side of equation (1) above.
The rolling torque Gm is calculated, for example, at 1000 times/second according to the formula, and the ratio (Gm/P) between the rolling torque Gm and the rolling pressure P is determined.

The torque arm lock-on circuit 2b samples the ratio of rolling torque Gm to rolling pressure P (Gm/P) n times, for example, about 50 times, calculates the average value a0 using the following equation, and calculates this by using the following equation. Remember.

[0013]

[Equation 2] This means that the ratio between the rolling pressure P applied to the rolling stand holding the material to be rolled and the pure rolling torque Gm required for rolling is "constant regardless of the rolling state". According to theory, this average value a0 is called the torque arm.

[0014] Then, when the rolled material advances further and its tip is bitten by the i-stand, a tension Tm is generated between the i-stand and the i+1 stand, so the generated tension calculation circuit 3 calculates this tension using the following equation. Calculate Tm.

[0015]

[Math 3] however, K7: Constant It is.

[0016] The tension calculation circuit 4 also has an i-stand and an i+
The deviation ΔT between the tension setting value Tref of a tension setting device (not shown) that sets the tension between one stand and the calculated tension Tm is determined by the following equation.

ΔT=Tm−Tref

...(4) Therefore, the proportional-integral circuit 5 is
) The tension deviation ΔT obtained by the equation is proportional and integrated, and is provided to the speed control device 10 as a speed correction amount ΔN.

Thus, the tension control device 11 uses the calculated and stored torque arm to control the inter-stand tension in front of its own stand to be constant or zero after the tip of the material to be rolled is bitten by the adjacent stand.

[0019]

[Problems to be Solved by the Invention] The conventional tension control device described above uses the rear tension TB to determine the torque arm a0. The tension may not be stable and the torque arm a0 may contain a large error.

That is, when changing the shape of the rolling stand or changing the rod of the material to be rolled, the speed setting and rolling reduction setting of the rolling stand include a considerable amount of error. Therefore, when the material to be rolled is bitten by the next stand, a compressive or tensile force acts on the material to be rolled between the rolling stands. Originally, tension control is performed so that the tension is constant, but the response of tension control in continuous rolling mills cannot be made fast to avoid mutual interference with the machine, and as a result, the rear tension becomes unstable. The torque arm a0 of the own stand is calculated in the state of , and as a result, the torque arm a0 includes a large error.

Therefore, in the conventional tension control device,
Tension must be controlled using a torque arm with a relatively large error, which sometimes makes it impossible to obtain a product with high dimensional accuracy.

The present invention was made to solve the above problems, and even if the backward tension becomes unstable due to a change in shape or a change in the rod of the material to be rolled, it is possible to achieve high dimensional accuracy through stable rolling. The purpose of the present invention is to provide a tension control device that can obtain a product.

[0023]

[Means for Solving the Problems] The present invention is provided for each stand of a continuous rolling mill, and rolls the stand from when the tip of a material to be rolled is bit into the stand to when it is bit by the adjacent stand. a calculation means for calculating a ratio between torque and rolling pressure; and calculation and storage means for sampling the calculated ratio of rolling torque and rolling pressure, calculating an average value of a plurality of sampling values, and storing the average value as a torque arm. In a tension control device that uses this calculation and a torque arm stored in a storage means to control the forward tension of the own stand after the tip of the material to be rolled is bitten into the adjacent stand, the predicted storage means for storing standard torque arms for rolling schedules and rolling grades;
Comparing the ratio of the rolling torque and rolling pressure calculated by the calculation means with the torque arm of the storage means, and removing those whose deviation exceeds a predetermined value from the sampling targets of the calculation and storage means, and selection. It is equipped with means.

[0024]

[Operation] In this invention, the predicted rolling schedule and standard torque arm for the rolling material are stored, and this torque arm is compared with the calculated ratio of rolling torque and rolling pressure. , those whose deviation exceeds a predetermined value are excluded from the sampling target of torque arm calculation, so even if the rear tension becomes unstable due to a change in shape or a change in the rod of the rolled material, the torque arm with a small error can be used. As a result, products with high dimensional accuracy can be obtained through stable rolling.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, and the same reference numerals as in FIG. 4 indicate the same elements. For the components shown in FIG. 4, the torque arm table 6 is referred to between the torque arm calculation circuit 2a and the torque arm lock-on circuit 2b, and an inappropriate torque arm is removed from the torque arm lock-on circuit 2b. It has a configuration in which a comparison and selection circuit 2c is added to prevent it from being handed over as a sampling value.

The torque arm table 6 is used to learn and store the torque arm a0' of the rolling stand for each rolling schedule and rolling material type when a stable rolling condition is achieved. The comparison and selection circuit 2c also calculates the ratio (Gm/P) of rolling torque Gm and rolling pressure P calculated by the torque arm calculation circuit 2a.
and the torque arm a0' of the torque arm table 6, and when the difference exceeds a predetermined value, the ratio (Gm/P) of the rolling torque Gm calculated by the torque arm calculation circuit 2a and the rolling pressure P is calculated. , is selected so as not to be delivered to the torque arm lock-on circuit 2b as a sampling value when calculating the torque arm.

The operation of this embodiment configured as described above will be explained below.

First, when a stable rolling condition is achieved through manual success intervention by the operator, that is, when the speed settings between each rolling stand are balanced and a product with good dimensional accuracy is obtained. , the torque arm a0' of each stand is stored in the torque arm table 6 according to the operator's judgment or the like. This is performed in a state in which the tension control is "off", that is, in a state in which the speed correction amount ΔN is not output to the speed control device 10. By performing this operation for each rolling schedule and rolling material type, a large number of torque arms a0' corresponding to the rolling schedule, rolling material type, etc. are stored in the torque arm table 6.

Next, when starting a new rolling process by changing the shape or changing the rod of the material to be rolled, the tip of the material to be rolled is bitten by its own stand until just before it is bitten by the adjacent stand. The deceleration current removal device 1 is the first on the right side of equation (1).
Each of the terms from term to third term is calculated, and the result of the calculation is delivered to the torque arm calculation circuit 2a. The torque arm calculation circuit 2a calculates the rolling torque Gm based on equation (1), and then calculates the ratio (Gm/P) between the rolling torque Gm and the rolling pressure P.

Here, the comparison and selection circuit 2c compares the ratio (Gm/P) between the rolling torque Gm and the rolling pressure P calculated by the torque arm calculation circuit 2a with the same ratio (Gm/P) stored in the torque arm table 6 in advance. The schedule and torque arm a0' of the same grade are compared using the following formula.

a0′−α1<(Gm/P)<a0′+α
2...(5) However, α1, α2: Constants.

[0032] Then, the ratio (Gm
/P) is not within the range of formula (5), the value is judged to include a large amount of error, and the torque arm determination circuit 2c samples the ratio (Gm /P) to the torque arm lock-on circuit 2b. Stop passing it as a value. As a result, the torque arm a calculated using equation (2)
0 is the average value of the ratio of a plurality of rolling torque Gm and rolling pressure P that satisfies the formula (5), and it is possible to calculate the torque arm a0 with little error. In this case, suppose that the torque arm lock-on circuit 2b averaged 50 sampling values, and only 49 sampling values were obtained because the comparison and selection circuit 2c stopped passing them on as sampling values. , this 49
The data will be averaged. The tension calculation circuit 3 generates the torque arm a0 obtained in this way.
By giving , it is possible to obtain an inter-stand tension with little error, and even when the rear tension TB is unstable, rolling with high dimensional accuracy can be achieved.

In the above embodiment, the torque arm a0' was learned using the torque arm table 6 and the stored value was used; however, instead of this, a setting device was provided to set the torque arm a0' for each rolling stand. The comparison may be made using equation (5) using the torque arm a0' set by the operator. According to this method, the torque arm of each rolling stand can be set arbitrarily.

On the other hand, the torque arm a0 of each rolling stand
Alternatively, the value of a0' may slightly change due to various conditions such as thermal rundown and skid marks of the rolled material, but a correction circuit is added to each torque arm table 6 to correct this. By doing so, dimensional accuracy can be further improved. In this case, a variable resistor or a rolling load or rolling temperature detector may be used as the correction circuit.

[0035]

Effects of the Invention As is clear from the above explanation, according to the present invention, the standard torque arm and the calculated ratio of rolling torque to rolling pressure are compared, and if the deviation exceeds a predetermined value, the torque Since it is configured so that it is not used as a sampling value for arm calculation, a torque arm with small error can be obtained even if the rear tension becomes unstable due to a mold change or rod change of the rolled material, and this results in stable rolling. This makes it possible to obtain products with high dimensional accuracy.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing a schematic configuration of a general tension control system of a continuous rolling mill.

FIG. 3 is a block diagram showing the relationship between signal input and output of a general tension control system of a continuous rolling mill.

FIG. 4 is a block diagram showing the configuration of a conventional tension control device.

[Explanation of symbols]

1 Acceleration/deceleration current removal device 2a Torque arm calculation circuit 2b Torque arm lock-on circuit 2c Comparison and selection circuit 3 Generated tension calculation circuit 4 Tension calculation circuit 5 Proportional integral circuit 10 Speed control device 11 Tension control device

Claims (1)

[Claims] Claim 1: Provided in each stand of a continuous rolling mill, and calculates the ratio of the rolling torque and rolling pressure of each stand from when the tip of the material to be rolled is bit into the stand to when it is bit to the adjacent stand. a calculation means for sampling the calculated ratio of the rolling torque and rolling pressure, and calculation and storage means for calculating the average value of a plurality of sampling values and storing it as a torque arm; In a tension control device that controls the forward tension of the own stand after the tip of the material to be rolled is bitten into the adjacent stand using a torque arm stored in the means, The storage means for storing the standard torque arm of the storage means is compared with the ratio of the rolling torque and rolling pressure calculated by the calculation means and the torque arm of the storage means, and the one whose deviation exceeds a predetermined value is A tension control device comprising computation, comparison and selection means for excluding sampling targets of storage means.