JPS5824914A - Speed controlling device for continuous rolling mill - Google Patents

Abstract

PURPOSE:To continue rolling without giving external disturbance to a speed between stands, by stopping the speed correcting function to a stand coincident with a maximum speed limit value and taking required amount only for a speed command value of other stands. CONSTITUTION:A speed command value to each stand is operated at a master controlling system and a speed command value to a stand 11 is subjected to the limit of maximum speed. In this case, a detecting circuit 101 inputs the sum of successive 19 of a down stream stand and a stand itself with an output of a speed reference device 14 and adder 17. Thus, an output signal 102 from the circuit 101 is opened, the speed correction by the successive to the stand 11 is stopped and the reference device 14 is held at the specified speed limit of stand. The circuit 101 outputs the amount of successive inputted after the detection of the stand speed limit to stands 21,31,41 and 51 as an inverting successive value 104.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a speed control device for a tandem continuous rolling mill.

In a hot strip mill or a wire rod mill that consists of multiple rolling mills, when changing the relative speed relationship between the stands, the interaction between the other stands (constant mass flow relationship) must be changed. In order to apply a disturbance to the
t-corrected at the same ratio. This is called general busy successive operation. Therefore, the speed command value of the mill is given by combining the preset standard and the above-mentioned successive quantity, but the final output stage of this speed command has the highest A speed limiter is installed to prevent the speed command output from exceeding the maximum speed.

However, according to such a configuration, if the speed command value of a certain rolling mill falls into this speed limit trap, it is impossible to output the speed command output exceeding the limit value, and the speed between the stands becomes I'm so busy disrupting relationships. This relationship will be explained with reference to block diagrams of a conventional speed control device for a continuous rolling mill shown in FIGS. 1 and 2.

The fR1 diagram is a block diagram of a nine control device constructed assuming an analog control system. S is the material to be rolled, 11th to 51st rolling rolls of the first to fifth stands, 12th to 52nd rolling mill driving motors and their speed control devices, 13 to 53 are maximum speed controllers, 15 to 45 and 15 a - 35a adder, 16 to 56 are multipliers, 14 to 54 are speed reference devices (5IRH) for each stand, and VR is a manual height control adjuster (not shown) that finely adjusts the speed of the stand. Vernier controller that integrates all devices, 1 is main speed setting device (MRH)
It is.

The speed setting before rolling starts on a continuous rolling mill, that is, the speed during mill set-up! The reset (initial speed cone) is controlled by adjusting the main speed setting device 1 and the speed reference devices 14 to 54 so as to satisfy the following relationship.

Stand speed is RPM = MRHX 5SRH... (
1) HXV = constant (mass flow constant law> ,,,,
. (3) If rolling is started and the initial speed cone is not at an appropriate value, excessive tension, loops, etc. will occur, and the above equation (
3), which deviates from the principle of constant mass flow. The vernier controller VR absorbs this, and as a result of the calculation of this vernier controller, the speed command value of each stand is calculated by the above equation (
The initial preset value of 1) is corrected and becomes the value shown in equations 4 to 6 below. By outputting this value to the speed control devices 12 to 52], again! It is controlled to satisfy the constant flow law.

RPM = MRHx 5SRH+ (Vvr + a
) ”(4)v ==iQpMxt x ox (
1+f) ... (5) HXV E=constant
...(6) However, vvr nistantonood-near output ・ ;Successive control output In this case, the basics of the constant mass flow law are the same.0 In the figure, 17 to 37 are adders, 18 to 5
8 is based on stand alone speed Tol) RPM/S
It is given in EC. 19 to 49 are rotational speeds (FIPM)
) is the successive amount given by 1/s@e of the current value. In addition, this mill uses the 5th stand as the standard stand.

In this control device, the successive quantities are multipliers 16 to 46,
The signal is supplied to the speed reference devices 14 to 44 through adders 15 to 45, and the output of the speed reference devices 14 to 44 is proportional to the input value. Here's how fast you can set it up! The reset (initial speed cone setting) is set according to the individual speed standards 18 to 58.

If rolling is started and the initial speed cone is not an appropriate value, excessive tension, loops, etc. will occur as in the previous example. To fix this, use a successive amount of 19-4
You can operate it at 9. For example, if you operate the successive amount 49 of the /f64 stand at 1% / s・C,
All upstream stands are operated at 1%/sec. The output of the reference devices 14 to 44 at that time is multiplied by 4/s@at-multipliers 16 to 46 to obtain the speed command (RPM) of each stand.
/l@IC).

In the configurations shown in FIGS. 1 and 2 above, maximum speed limiters 13 to 53 are provided to prevent the motor from overspeeding when the rolling mill motor drive device is turned into a final output stage. Because of this, the speed command cannot be output as a speed command exceeding this maximum speed limit.Therefore, there is a drawback that the speed f relationship between the stands is revealed.

Conventionally, the following methods have been adopted to improve this drawback.

A. Keep the maximum value of the initial speed cone within a certain range (usually 96% or less) below the maximum speed limit to provide a margin for successive control. Add the maximum value of successive K11li. (Usually within 10 to 15-15%.) B. When it is confirmed that the maximum speed limit value has been applied, the main speed setting device (MRH) K is lowered by a predetermined amount, either manually or automatically.

However, if the maximum value of the certified range of the initial speed cone is kept low even as described above, the speed tube of the rolling mill cannot be used with a lower overall speed, and the capability of the rolling mill cannot be fully utilized.

Also, in I above, since the main speed setting device (MRH) speed is normally very slow, it is impossible to follow sudden speed changes due to vernier speed control, and the transient speed balance between trap stands is difficult to follow. It has the disadvantage that it collapses.

In addition, in the configuration shown in FIG. 2, the configuration is such that the speed reference devices 14 to 4 can be directly operated by successive operations.
The outputs of each of the speed standards 914 to 54 are configured to correspond to the rate of change in speed, so the problems with 11 mentioned above have been eliminated.

This invention has been made in view of the above-mentioned nine points. For example, when the speed command value of a certain stun r due to the successive amount exceeds the maximum speed limit value, the timing that coincides with the maximum speed limit value is detected. At that point, the speed correction function based on the successive amount for the relevant stand will be discontinued.
By calculating and controlling the speed command values of other stands other than the stand concerned by correcting (reducing) them by the necessary amount, it is possible to maintain a speed at which rolling can continue without affecting the speed balance between the stands. It is intended to provide a control device.

An embodiment of the present invention will be described below based on the drawings.

FIG. 3 is a block diagram thereof, and the same parts as in FIG. 2 are given the same numbers. In the present invention, maximum speed limit value detection circuits 101 to 401 and adders 203 to
503.205 to 405 and the maximum speed limit value detection circuit are equipped with output signals 102 to 402 which become "open 6" when the stand speed command matches the maximum speed limit value. Also, 104 to 404 are ◆high This is a reverse successive signal that is output when the speed command of the stand matches the maximum speed limit value in the speed limit value detection circuit.

Now, as a result of calculating the speed command value for each stand in the main control system, the speed command value for the first stand is the maximum speed control K.
Suppose it takes. In this case, the detection circuit 101 receives the sum of the successive values 19 of the downstream stand and its own stand from the output of the speed reference device 14 and the adder 17Vr-.

As a result, RPMl = SSRHrpm where RPMl: Stand speed limit value SSRHr
pm: The output signal 102 from the detection circuit 101 becomes 1 open 1 when the speed reference device outputs, and the speed correction by successive to the rotary 1 stand 11 is stopped, and the speed reference device 14 changes to the stand speed limit value of RPM7. is retained.

However, if the successive 19 of the target downstream and self-stand added by the adder 17 trap continues to be input from then on,
The detection circuit 10101uRP outputs a child exceeding the stand speed limit value as a successive amount (%/sec) input after detecting the limit as a reverse successive side 104 to downstream stands after the A2 stand. This inverse successiveness works as follows.

5UC=SUCf −5USs−5UCr=
(7) However, suC: Successive amount (%/5ec)
suct: downstream success (%/5ee)
SUCs: Self-stand successive (1/sec
)SUCr: Successive C from upstream (reverse succession) (chi/s@c) According to the relationship in equation (7) above, the successive amount for the 42 stands is modified so as to decrease by the reverse successive amount 104. In other words, the speed command value is %/se of the reverse successive amount.
It is corrected in the deceleration direction by an amount corresponding to c and output. In the same way, the speeds of stands A2 to #65 are also corrected by the amount of this reverse distortion, and the constant mass flow law that is deviated due to the maximum speed limit of 1, /%1 stand r11 is corrected. I can do things.

As described above, according to the present invention, the timing at which the maximum speed limit value and the speed command value diverge is detected, and from this point forward, the speed correction by successives that are busy at the relevant stand is stopped, and the The speed command value for 9 is HOL
D and further gives reverse successive to other stands, so the speed can be quickly corrected and the relative speed between the stands is always constant and not disturbed.

The present invention also has the advantage that the reference stand can be determined automatically, which is particularly effective when using a system such as a process controller or a computer.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a conventional speed control device using the analog control method, Fig. 2 is a block diagram of a conventional speed control device using the pulse preset method, and Fig. 3 is a block diagram of a conventional speed control device using the pulse preset method. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention. 11-51... Stand, 12-52... Rolling mill driving electric motor and speed control device, 13-53... Speed limiter, 14-54... Speed reference device, 15-55 and 17- 47 and tears ~ 503... adder, 1
6-56... Multiplier, 18-58... Single speed reference, 19-59... Successive, 101-401- Speed limit value detection circuit. Applicant's representative Kiyoshi Inomata No. 5 stand No. 4 stand N
o, 3 stands No, 2 stands No
, l stand figure 2

Claims (1)

[Claims] In the speed control device of a continuous rolling mill where the maximum speed of each rolling mill is limited, there is a speed reference device that can independently preset the speed of the rolling mill in each stand when the rolling mill is busy, and a speed reference device that can set the maximum speed or speed command value of each stand. A speed limit value detection circuit that detects a speed difference and outputs a speed correction signal capable of correcting the rolling mill speed WjL of the stands upstream from the specific stand or downstream of the company at the same ratio; or a device for guiding a correction signal applied to the rolling mill of the specific stand to the upstream side or the downstream side in order to correct the speed tt of the rolling mills of the stands connected downstream at the same ratio; and a speed correction signal guided from the specific stand. A speed control device for a continuous rolling mill, comprising a device for combining the outputs of the speed reference device and the speed reference device and changing the setting value of the speed reference device of each stand.