JPS6231650A - Controlling method for meandering of strip - Google Patents

Abstract

PURPOSE:To stabilize steering operation by generating the output of control amount corresponding to meandering speed obtained by the differentiation of meandering amount of a strip with gain changed to be inversely proportional to line speed detected. CONSTITUTION:A strip 10 passing by a ringer roll 12 has the meandering amount Y in the widthwise direction detected by a strip position detector 20 and the signal of said mount Y is sent to the input of a first amplifier 28 to be converted to voltage which is differentiated by a differentiating circuit 30 so that the meandering speed dy/dt of the strip 10 is detected. The meandering speed is amplified by gain Kt inversely proportional to line speed v in a second amplifier 32 to be converted to current value and sent to the input of an electricity/oil pressure converter 34. Said converter 34 sends oil amount corresponding the current value input to a hydraulic cylinder 14 which drives the ringer roll 12 about a tilting center 16. By such drive is properly corrected to the meandering of the strip 10.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for controlling the meandering of a strip, and is particularly suitable for use in controlling the meandering of a strip in a continuous processing line such as a pickling line. The present invention relates to an improvement in a strip meandering control method in which the strip meandering is controlled by a steering roll having a tilting center on one side of a strip processing line. [Prior art 1] Currently, for example, as a strip meandering control 1B used in a pickling tank of a continuous pickling line, a pinch roll type Ringarol C is used in which the Ringer roll on the detection side is steered.
P C (center position control)
l) The device is present. As shown in FIG. 3, the steering method normally used in this Ringer Roll CPC device is to wind the strip 10 around the Ringer Roll 12, which is supported by a frame 15 and has a tilting center 16 on one side of the line. The strip 10 is passed in the width direction by tilting the Ringer roll 12 using the hydraulic cylinder 14 to change the passing position of the strip 10 in the width direction. Here, the relationship between the position X of the hydraulic cylinder 14 and the deviation (meandering amount) of the widthwise passing position of the strip 10 is derived from FIG. 3 as shown in the following equation. X proverb W tanθ ・・・・・・・・・・・・・・・
...(1) dy/dt=v cos θsin
θ・・・・・・ (2) Here, W is Lingarol 1
2, the tilting radius θ is the tilting angle of the Ringer roll 12,
is the line speed of the strip 10. (1) (2> In the equation, when θ<<1, sinθΣθ
, cosθ hull 1, the following equation holds true. dy/dt −(v/W) x−−・=−(3) In other words, the correction speed (d
It can be seen that V/dt) is proportional to the position X of the hydraulic cylinder 14, that is, the roll tilt angle θ. By the way, using the apparatus shown in FIG.
Meandering! II! A conventional control system for illumination is as shown in FIG. In FIG. 4, the control that feeds back the cylinder position is called P1 control, and the control that does not feed back the cylinder position is called P2 control. Also, R(S) is the target II! which is the reference input. (usually at the center of the line, that is, zero), G+(S) is a transfer function representing the characteristics of the hydraulic servo valve that controls the position of oil flowing into the hydraulic cylinder 14, and G2(S) is the transfer function of the hydraulic servo valve that controls the position of the oil flowing into the hydraulic cylinder 14. A transfer function representing the characteristic, G3(S), is a transfer function (actuator transfer function) that converts the movement of the hydraulic cylinder 14 into a movement of the strip 10, D(S) is a disturbance, and C(S) is a transfer function that converts the movement of the hydraulic cylinder 14 into a movement of the strip 10. width direction position, H
(S) is a transfer function representing the characteristics of the strip position detector that detects the widthwise position of the strip 10, Kt is the gain of the amplifier that amplifies the input signal, and Kp is the feedback amount of the position of the hydraulic cylinder 14. This is the gain to be adjusted. [Problems to be solved by the invention] Now, each transfer function of the control system shown in FIG.
(S)=1.0, G2 (S)=1/S, Gs(S)-
(v/W)・('1/S), H(S)-1,0, the round transfer function A1 (S
) is calculated as follows. Ao (S)=to/S2--- (4) Here, K is expressed by the following formula. K −K t V / W ・・・・・・・・・・・・
(5) At this time, the characteristic equation of the system is as shown in the following equation. 1 + (K/S 2 )−0・・・・・・・・・(6
) Since K>O, the solution to equation 6) is as shown in the following equation. S-±iC [ ・・・・・・・・・・・・・・・・・・
(7) Therefore, it can be seen that this system is at the limit of stability. In other words, the response to step input will never converge! i! ! I end up repeating 7J. On the other hand, when performing the P1 control, the open-loop transfer function A1 (S
) is as shown in the following equation. A+ (S)-7' (S (S+Kt/Kp))
(8) The characteristic equation in this case is as follows. 1+, / (S (S+Kt/Kp))=O...(
9) The solution to this equation (9) is the following equation. 5=(-Kt/Kp+ t,-p-)/2
・・・・・・・・・・・・・・・(10) As can be seen from equation (10), the larger the feedback gain Kp, the smaller the negative real part of S becomes.
This system approaches its stability limit. Therefore, in order to make the system more stable, the feedback gain Kp must be reduced. However, if the feedback gain Kp is reduced,
One of the solutions of S shown in equation (1o) (the sign is the root of 10) becomes close to zero, and the convergence of the response to the step input becomes slow. This is because, as is clear from FIGS. 3 and 4, the feed bar tilting angle .theta. becomes smaller and the correction speed of the strip 1o becomes slower. Therefore, with the usual steering system in which the tilting center 16 is on one side of the line, it has not been possible to accurately control the meandering of the strip 10. Therefore, in the past, the steering system had to be a system in which the tilting center 16 of the ringer roll 12 coincided with the line center, and the correction my of the strip 10 was made proportional to the amount of cylinder movement, as shown in FIG. . However, this system has a problem in that the amount of money required for equipment is more than double that of the above-mentioned normal steering system in the R position. (Object of the Invention) The present invention has been made to solve the problems of the conventional art mentioned in n. It is an object of the present invention to provide a strip meandering control method that can be corrected and that can always provide the best control regardless of the line speed. In a strip meandering control method in which the strip meandering (1) is controlled by a steering roll having a tilting center on one side of the strip, the meandering amount and line speed of the strip are detected, and the detected meandering amount is differentiated. The above purpose is achieved by stabilizing the steering action by determining the meandering speed by determining the meandering speed, and outputting a control amount according to the meandering speed by changing the gain so as to be inversely proportional to the detected line speed. [Function] In the present invention, as shown in Fig. 1, the amplifier output' is improved by inserting a differential element S into the amplifier in the υj control system shown in Fig. 4 above, and P2 control is achieved. Even when pulling
This ensures that the control system is stable. Furthermore, by changing the control gain not at a constant value but inversely proportional to the line speed V, meandering control can always be performed with the best gain. That is, in the control system according to the present invention shown in FIG.
The number of one-cycle transfers A3 when controlling (goods) is as follows: 1 + K/”S −0・・・・・・・・・(12
) When the root of this equation (12) is found, it becomes as shown in the following equation. 5--K・・・・・・・・・・・・・・・(13
) Since K > O, this system is stable, and moreover, K
By increasing , the response speed to step input can be increased. At this time, the cylinder 14, that is, the roll tilt angle θ, moves in proportion to the meandering speed dy/dt of the strip 10, rather than the meandering amount y of the strip 10. That is, the meandering is corrected so that the greater the meandering speed dy/dt of the strip 10, the greater the roll tilt angle θ. On the other hand, as is clear from equation (5) above, when the amplifier gain Kt is constant, the line speed V
increases in proportion to. Therefore, as the line speed increases, hunting may occur if the amplifier gain Kt is large. Therefore, in the present invention, the line speed V is always taken into account and the amplifier gain Kt is changed inversely proportional to the line speed V, so that the control system is always kept in a stable state. Therefore, according to the present invention, even if the steering roll has a tilting center on one side of the line, it is possible to perform stable meandering control that has good responsiveness and is not affected by the line speed. [Example] Hereinafter, with reference to the drawings, an example of a meandering control m+ device installed on the pickling tank exit side of a continuous pickling line, in which the present invention is adopted, will be described in detail. In FIG. 2, a ringer roll 12 for winding the strip 10 pickled in a continuous pickling tank (not shown) and controlling its meandering is disposed on the outlet side of the pickling tank. A frame 15 that supports the Ringer roll 12 is disposed, and a hydraulic cylinder 14 that drives the Ringer roll 12 via the frame 15 is attached to one end of the Ringer roll 12 in the axial direction. It is arranged. 1
6 is a driving center when the Ringer roll 12 is driven in the direction of arrow B. Furthermore, a strip position detector 20 for detecting the widthwise position of the strip 10 and a priddle roll 22 for conveying the strip 10 while maintaining tension are disposed at the end where the strip 10 is passed. . A pulse counter 24 is disposed on the priddle roll 22 for converting its rotational speed into pulses and detecting the line speed (1) of the strip 10. On the other hand, the snake control device is equipped with a control section 26 for driving the hydraulic cylinder 14. a first amplifier 28 that converts y into voltage;
Differentiating the voltage signal output from the first amplifier 28,
A differentiating circuit 30 for determining the meandering speed dl//dt of the strip 10, and a second amplifier that amplifies the meandering speed with a gain Kt (V) inversely proportional to the line speed (2) and converts the value directly into a current. 32 plus A. In addition, 34
is an electro-hydraulic converter that converts the current value obtained by the second amplifier 32 into the amount of oil for driving the hydraulic cylinder 14. The operation of this embodiment will be explained below. The strip 10 sent out in the direction of the arrow from a pickling tank (not shown) is first wound around a ringer roll 12. The strip 10 that has passed through the ringer roll 12 is
The meandering amount y in the width direction of the strip is detected by the strip position detector 20, and the line speed (■) of the strip 10 is detected by the pulse counter 24 connected to the priddle roll 22.
Detected in Here, the meandering speed dy/of the strip 10 is differentiated by the detection differentiation circuit 30 in the strip position detector 20.
dt is detected. The meandering speed is determined by a gain Kt (V) which is inversely proportional to the line speed (2) in the second amplifier 32.
is amplified, converted into a current value, and inputted to the electro-hydraulic converter 34. The electro-hydraulic converter 34 sends an amount of oil to the hydraulic cylinder 14 according to the input current value. The hydraulic cylinder 14 is operated by electric oil and drives the Ringer roll 12 with the tilting center 16 as a fulcrum. By driving the Ringer roll 12, the meandering of the strip 10 is properly corrected. In the embodiment described above, the strip 10 is meandered by the Ringer roll 12 provided in the pickling line! Although the apparatus for performing ldl''m has been exemplified, the steering roll to which the present invention is applied is not limited to this, and may be applied to, for example, a steering roll that uses a pinch roll that pinches the strip 10 from above and below at a pond line. (Effects of the Invention) As explained above, according to the present invention, even in a steering roll where the center of tilt is on one side of the line, meandering control of the strip can be performed stably. It is extremely economical, as the cost required for the equipment can be reduced to 1/72 to 1/3 compared to the steering roll used in conventional steering rolls.In addition, the best meandering control is always achieved regardless of the line speed. It has excellent effects such as:

[Brief explanation of drawings]

FIG. 1 is a block diagram for explaining the principle of a strip meandering control method according to the present invention, and FIG. 2 shows an embodiment of a continuous pickling line meandering control method to which the present invention is adopted. A plan view including a partial block diagram; FIG. 3 is a plan view showing an example of a conventional steering system using ringer rolls; FIG. 4 is a block diagram showing a conventional control system used in the steering system. FIG. 5 is a plan view showing another example of a conventional steering system using a ringer roll. DESCRIPTION OF SYMBOLS 10... Strip, 12... Ringer roll, 14... Hydraulic cylinder, 16... Tilting center, 2000. Yu8. ．． t, □*taps,
I24...Pulse counter, 26...Control unit, 28.32...Amplifier, 30...Differentiating circuit.

Claims (1)

[Claims] (1) In a strip meandering control method in which the meandering of the strip is controlled by a steering roll having a tilting center on one side of the strip processing line, the meandering amount and line speed of the strip are detected, and the detected meandering amount The steering action is stabilized by differentiating the line speed to obtain a meandering speed, and outputting a control amount corresponding to the meandering speed while changing a gain so as to be inversely proportional to the detected line speed. Strip meandering control method.