JPH0241712A - Catenary control method for continuous conveying steel plate - Google Patents

Abstract

PURPOSE:To control the catenary value of the conveying steel plate in constant by issuing a tension command based on an arithmetic expression corresponding to the change of the unit tension decided by a travelling value of the connected part of the steel plates having different sections and the ratio of sectional areas of the steel plates and by controlling roll driving motors. CONSTITUTION:When the conveying steel plate has the plate joint parts with different sectional areas, the unit tension changing corresponding to the travelling value of the plate joint parts 1C from the inlet side roll 3 is operated by the arithmetic expression, corresponding to this result, the tension command is issued to control the roll driving motors 5, 7 to make the catenary value D to be constant. Therefore, even if the unit tension is changed following the travelling value of the plate joint parts 1C from the inlet side roll 3, the catenary value D can be controlled to be always constant. Further, as to the arithmetic expression, any sorts of arithmetic expression can be used without restriction.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a catenary control method for a continuously conveyed mesh plate when steel plates are continuously carried into an oven for processing such as coating drying. It is.

(Prior Art) For example, when a steel plate is continuously carried into an oven for coating and drying, no support rollers or the like are disposed in the oven between the entry roll and exit roll. Therefore, the central portion between the inlet roll and the outlet roll will sag, and the amount of sag (hereinafter referred to as "catenary amount") is determined by the tension of the roll drive motor that drives the steel plate in one general feed. In order to uniformly dry the steel plate in the oven, it is necessary to control the distance between the steel plate and the hot air nozzle to be constant on both sides. It is important to control.

Conventionally, as a method for controlling the catenary amount to a constant value, the first example is to control the circumferential speed of the input roll and the output roll to a constant value, and to keep the actual length of the steel plate between the two rolls constant. There is a method that attempts to control the catenary amount to a constant value by

As a second example, there is a method in which a height sensor is used to detect the position of the steel plate in the center of the oven, and the roll speed is controlled to keep the height (catenary amount) constant.

Furthermore, as a third example, there is a method of controlling the unit tension of the steel plate between the input side roll and the output side roll to be constant.

(Problems to be Solved by the Invention) The above conventional examples each have the following problems. That is, in the first example, there was a problem in that the influence of slip between the roll and the steel plate gave a steady error to the catenary control. Furthermore, in the second example, there was no suitable sensor that could be used in the oven, and there was a problem with the reliability of the sensor. In the third example, when there is a plate joint of steel plates with different cross-sectional areas, the unit tension is different between the leading steel plate and the trailing steel plate when they pass, which causes an error in the amount of catenary.

The present invention has been made in view of the above problems, and
To provide a catenary control method for continuously conveyed steel plates that can control the amount of catenary without causing an error even when the plate joints are passed through in a tension control method when there are plate joints of steel plates with different cross-sectional areas. The purpose is to

(Means for Solving the Problems) In order to solve the above problems, the catenary control method for continuously conveyed steel plates of the present invention provides a catenary control method for continuously conveyed steel plates, which has different cross-sectional areas. In addition to tracking the amount of catenary, it corresponds to the result calculated to keep the catenary amount constant based on the calculation formula that corresponds to the change in unit tension determined by the traveling amount and the cross-sectional area ratio of the leading and trailing steel plates. It issues a tension command and controls the roll drive motor.

(Function) The present invention controls the roll drive motor by issuing a tension command in accordance with the calculation formula for the unit tension that changes in accordance with the travel distance from the roll on the inlet side of the plate joint, and as a result, the plate joint The catenary amount is controlled to be constant in response to the unit tension, which changes with the traveling distance of the part.

(Example) Hereinafter, an example of the present invention will be described based on FIG. 1.

In the figure, a steel plate 1 is carried into an oven 2 while being fed in the direction of the arrow by an inlet roll 3 and an outlet roll 4, and is subjected to processes such as drying the coating in the oven 2. It is something. here,
In the steel plate 1, the leading steel plate 1a and the trailing steel plate 1b are connected to the plate joint part 1.
Figure 3 shows a state in which the parts are connected by c and are being conveyed continuously.

5 is a motor for driving the input roll 3, 6 is a pulse generator that detects the rotation speed of the motor 5, and 7
8 is a motor for driving the exit roll 4, and 8 is a pulse generator for detecting the rotation speed of the motor 7. Further, reference numeral 9 denotes a plate joint sensor provided near the entrance roll 3, which detects the plate joint 1c between the steel plates 1a and lb.

Reference numeral 10 denotes a calculator that calculates a constant catenary amount, and calculates the catenary amount of the steel plate 1 to be constant based on a calculation formula described later, and issues a tension command in accordance with the result. This calculator 10 receives the detection signal of the plate joint IC from the plate joint sensor 9, and the output signal of the pulse generator 6 as a traveling distance detection signal from the entrance roll 3 of the plate joint 1c after the detection. is input, and various condition values set by the setting means 11 are also input.

Here, the settings set by the setting means 11 are as follows:
In addition to the reference tension determined by the tension setting device 12, the leading steel plate cross-sectional area 13, and the trailing steel plate cross-sectional area 14, necessary condition values such as the calculation formulas necessary for the calculations described later and the distance 1 between the input roll 3 and the output roll 4 are calculated. This will be done manually as appropriate.

15 is a tension control regulator, 16 is a line speed setting device, 17
18 is a speed control regulator, and 18 is a motor drive circuit. Here, the tension setting device 15 manually inputs the tension command output from the arithmetic unit 10 and the motor torque current value taken out from the transistor inverter constituting the motor drive circuit 18, and compares the two to determine the deviation. The value is issued as a speed correction signal for tension control. The speed correction signal is added to the line speed command signal output from the line speed setter 16 and input to the next speed control regulator 17.

The output of the pulse generator 8, that is, the actual speed of the motor 7, is further input to the speed control regulator 17, and based on these human inputs, calculations necessary for speed control of the motor are performed. The motor drive circuit is controlled by the output, and the speed of the motor 7 is controlled. The speed of the motor 7 is controlled to obtain a necessary line speed and a predetermined tension of the steel plate 1. Therefore, from the pulse generator 8 to the speed control regulator 17 and the motor drive circuit 18.
, the control loop of the motor 7 forms a speed control loop.

Next, the arithmetic expressions in the arithmetic unit 10 will be discussed. In general, the catenary ilD is expressed as: W: Weight of the copper plate l Distance between the rolls on the two person side and the exit side T: Tension of the steel plate. Here, the weight W of the steel plate is determined by assuming that its cross-sectional area A is constant and the proportionality constant is K, then W = A - K
...■, and if the tension T is expressed as unit tension IT, then T ``''A' T u
... If we substitute the 0 expression and the 0 expression into the 0 expression, we get . As is clear from this equation 0, the catenary i1D is inversely proportional to the unit tension Tu.

Therefore, in order to keep the catenary measurement constant, it is necessary to keep the unit tension Tu constant. By the way, steel plate l
When the cross-sectional areas of the leading steel plate 1a and the trailing steel plate 1b are different,
The unit tension T. As mentioned above, the two are different. Therefore, this unit tension T. The change in plate joint portion 1c that occurs as the plate joint 1c travels is determined, and based on the change in the unit tension Tu that occurs with the travel, a correction corresponding to the travel is performed to control the actual unit tension by the motor 7 so that it is always constant. This makes it possible to keep the catenary ilD constant.

Therefore, we will examine the tension control model equation. First, as shown in FIG.
It is assumed that this plate joint IC is sequentially traveled, and the distance from the entrance roll 3 to that position is indicated by Xwp. Also, the distance to the lowest point Q is X. , the distance between both rolls 3.4 is B
(I! in Figure 1 above), the height difference of the steel plate from the 3rd part of the incoming roll to the 4th part of the outgoing roll is C1, the unit tension is T"uo, the cross-sectional area of the leading steel plate is A2, and the trailing steel plate is Let A1 be the cross-sectional area and k(-A+/Az) be its different cross-sectional ratio.

Then, each value is analyzed under the following conditions.

B -37,66Cm), C=0.6 (m)x
o = 14.77 (m), -y o = Q point
0.428 [m]Tuo=2 (kg/mm”l
, k=1/2~2 The analysis results are shown in FIG. FIG. 3 shows the required unit tensions Tu+(Xwp+k) and Tuz(Xwp+k) with respect to the X coordinate (xwp) of the plate joint IC of the steel plate 1.
) is shown using the different section ratio k as a parameter.

Here, the simplified formula for finding TLl from the curve in FIG. 3 is shown as the simplified formula TU+! ■ Calculate the coefficient β of this equation 0 using the method of least squares. First of all, this 0
Transforming the formula, TLllE−a+βb −=
■Find this from the original data in Figure 3 and get β-4,6036X 10-5...
■Therefore, by substituting the various coefficients, x x wp(x wp-14,77) (x wp-
37, 66)...■Also, the X coordinate of the plate joint IC (
The actual length S of the steel plate 1 from the entrance roll 3 part at x, p) is approximated from the analysis result.

The expression ■ and [phase] obtained in the above manner are input to
and T RE F = A + X T u + t
... The tension command of this computing unit IO is issued by (2). Therefore, the plate joint part sensor 9 detects the plate joint part IC, and the plate joint part 1c is fed (
When the traveling) length (S above) is input sequentially by the signal from the pulse generator 6 and the XWII value is determined by the [phase] formula, since k has been determined in advance, TulE is determined by the formula 0.
will be determined sequentially. Then, the tension command T REF is determined by Equation 0 and is output from the calculator 10.

Note that the arithmetic expression set in the arithmetic unit 10 is not limited to the expression described above, and may be an expression obtained by another method.

(Effects of the Invention) As described above, according to the present invention, when there is a plate joint part with a brand new area of continuously conveyed steel plates, the unit tension changes in accordance with the traveling distance from the input roll of the plate joint part. Since we calculated it using an arithmetic formula and issued a tension command in response to the result to control the roll drive motor so that the catenary amount was constant, there was a plate joint with a brand new area. Even if the unit tension changes with the traveling distance of the plate joint from the inlet roll, the catenary amount can be controlled to always be constant. Therefore, it is a very effective invention because it can be used for drying steel sheets in ovens, etc., where processing is performed without support between the rolls on the input side and the output side, and stable treatment can be performed at all times.

[Brief explanation of the drawing]

The drawings show an embodiment of the catenary control method for continuously conveyed steel plates according to the present invention. Fig. 1 is a block diagram thereof, Fig. 2 is an explanatory diagram of the examination of the tension control model formula, and Fig. 3 is the plate joint as a result of the same analysis. FIG. 3 is a curve diagram showing changes in unit tension with respect to the traveling distance of the part. 1 is a steel plate, 1a is a leading steel plate, 1b is a trailing steel plate, 1c is a plate joint, 3 is an entry roll, 4 is an exit roll, D is a catenary amount, 5.7 is a motor, 10 is a computing unit, 15 17 is a tension control regulator, and 17 is a speed control regulator. Patent applicant: Sumitomo Metal Industries, Ltd.

Claims (1)

[Claims] (1) A catenary control method when processing a steel plate while continuously conveying it between an input roll and an output roll arranged at a constant interval, the leading steel plate and the trailing steel plate having different cross-sectional areas. The amount of catenary is calculated based on the calculation formula corresponding to the change in unit tension determined by the amount of travel from the entrance roll of the plate joint part and the cross-sectional area ratio of the leading and trailing steel plates. 1. A catenary control method for a continuously conveyed steel plate, characterized in that a tension command corresponding to a result calculated so that the tension is constant is issued, and a roll drive motor is controlled.