JPS5863089A - Controlling method for speed of motor in processing machine provided with plurality of roll stands - Google Patents

Abstract

PURPOSE:To prevent the generation of an abnormal value in a tension between stands by a method wherein an assumed fall of impact analogous to a fall of impact on the stands is generated by a load signal of the stands holding work to be processed between. CONSTITUTION:A work 3 to be processed is rolled while it is moved from a stand 1 on the upstream side to stand 2 on the down-stream side. A speed control unit 6 operates when it receives an output of a speed detector 5 and an output of a speed instructing unit 16 via an adder. An impact fall conpensating circuit 15 is constituted by a load controlling unit 12, a function generator 13 and a multiplier 14. An ouput of a current detector 10 of a motor circuit is inputted in the function generator 13 and the speed controlling unit 6. A output of a load cell 11 is multiplied by a constant delivered from the speed instructing unit 16 in a multiplier 17, and a multiplied value thus obtained is inputted in the load controlling unit 12 via an adder. A driving current of a motor 4 is controlled by an ignition angle controlling unit 7 and a current controlling unit 8.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a processing machine that includes a plurality of roll stands and processes the same workpiece while moving it from upstream to downstream. This article is about the motor speed control method.

Tandem rolling mills, rubber/plastic processing machines, paper machines, and the like are known as the above-mentioned processing machines equipped with a plurality of roll stands. In such a processing machine, every time the workpiece moves and bites into a roll provided on a roll stand on the downstream side, the speed of the electric motor decreases (impact drop). When this impact drop occurs,
Abnormal tension is applied to the workpiece, which worsens the machining condition.

In order to eliminate this impact drop, it would be sufficient to increase the responsiveness of the speed control system of the processing machine, but there are limitations such as the screw axis vibration between the electric motor and the pressure processing machine.

In addition, the method proposed in 1% Application No. 50-28033 (hereinafter referred to as the impact drop compensation method) has a considerable effect in reducing the impact drop, but the detection delay of the load cell, It is not possible to completely eliminate the impact drop due to delays in the minor loop constant current control system.

Next, let's take speed control of a tandem rolling mill as an example.

The conventional technology will be explained. Fig. 1 is a block diagram of the speed control system of a tandem rolling mill, and shows any two stands (shown as Todoroki stand and stand 111) of the tandem rolling mill, which is composed of 6 to 7 roll stands.
It is a diagram in which a portion is extracted. In the figure, 1 is one stand (upstream side).

2 is a 1-1-1 stand (downstream side), and the workpiece 3 is rolled while moving from the upstream side to the downstream side.

4 is an electric motor, and 5 is a speed detector that detects the rotational speed of the electric motor 4. Reference numeral 6 denotes a speed control section that operates by receiving the output of the speed detector 5 and the output of the speed command section 16 via an adder. In addition, 15 is the above-mentioned patent application No. 50-2803.
With the impact drop compensation circuit disclosed in No. 3,
It is composed of a load control section 12, a function generator 13, and a multiplier 14.

10 is a current detector of the motor circuit, the output of which is input to the function generator 13 and the speed control section 6. Mae, 1
1 is a load cell, its output is the load control section 121C
It has been entered. 7 is the output of the speed controller 6, the output of the multiplier 14 in the impact drop compensation circuit 15, and the current detector l.
This is a current control unit that receives the outputs of O through adders and controls the drive current of the electric motor 4. Further, 8 is a firing angle control section, and s9 is a thyristor bridge that actually controls the drive current of the electric motor 4.

FIG. 2 is a waveform diagram showing the operation of the speed control system of the conventional tandem rolling mill shown in FIG. W, l is the steady angular velocity of the i stand, W, (river) is the steady angular velocity of the 1-4-1 stand, WI is the angular velocity of the i stand, town, 1 is the 1-1
The angular velocity of the −1 stand and T indicate the tension of the workpiece 3 between the i stand and the 1-1-1 stand.

That is, as shown in FIG. 2 (Hata), at 1 time 1. The workpiece 3 is bitten by the i-stand, and therefore the steady angular velocity of the i-stand becomes a small value due to the impact drop. Eventually, at time 'i*1, the workpiece 3 reaches the l+1 stand, and the steady angular velocity Wt (S
The angular velocity maintained at et) is.

Due to the large area impact drop, the value becomes small. For this reason, the workpiece 3 between the star stand and the i+l stand becomes sagging υ, and as a result, a situation occurs in which the tension T#i is not generated in the workpiece 3, as shown in Figure 2). This slack in the workpiece 3 is removed by speed correction control using the tension control system or the looper, but due to the delay K in the control system, the correction control is started at time t shown in Figure 2). Naru 0
Time sound.

, the angular velocity increases, the area A for the impact drop is canceled by the area BK, and the specified tension between the stands T,
is established as shown. Therefore.

In the conventional means, 1. This required time. Therefore, the workpiece 3 rolled for 5 hours t- becomes thick and off-gauge. Refreshingly, the sagging of the workpiece 3 between the stands during narrowing induces the so-called sinking phenomenon in thin plates, causing misrolls. Further, in the case of a thick plate, compressive force is applied to the processed material 3, which is not preferable.

Therefore, the actual speed is set higher than the steady rolling angular speed &'') (Ill) by ΔW, as shown in FIG. 2(C)K, so that the tension T is always generated.However.

The response delay K of the tension control system or looper control system may cause an abnormally high tension T to occur as shown in FIG. . That is, determining the value of ΔW is a big problem, and the actual situation is that the value is determined based on experience and intuition.

The present invention was made in view of the drawbacks of the conventional motor speed control method for processing machines equipped with a plurality of roll stands. It is an object of the present invention to provide a method for controlling the motor speed of a processing machine equipped with a plurality of roll stands that quickly generates tension between the stands.

The motor speed control method for a processing machine equipped with a plurality of roll stands of the present invention detects a speed drop that occurs in the downstream roll stand motor when a workpiece is bitten by the rolls of the downstream roll stand. Based on the detection result, causing each electric motor of all the roll stands on the upstream side of the downstream roll stand to cause a speed drop that is a phase image of the speed drop that occurred in the electric motor of the downstream roll stand,
This prevents abnormal tension from being applied to the workpiece and quickly establishes the specified tension between the stands.

The present invention will be described in more detail below with reference to embodiments shown in the accompanying drawings.

Fig. 3 shows a first embodiment in which the present invention is applied to a speed control system of a tandem rolling mill.The same parts as the conventional one shown in Fig. 1 are given the same symbols and explained. omitted.

The difference from the nine conventional ones shown in FIG. 1 is that the load cell 11
The load signal detected by the multiplier 17 on the i-stand 1 side
, the constant output from the speed command section 16 is multiplied by , and this multiplied value is input to the load control section 12 via the adder.

Here, the constant kK is % i and the rolling schedule of 1+1, which is the first stand advance rate, the first +1 stand backward rate, and the first stand. The constant determined by the roll diameter of the 44th-1st stand is 69. It can be calculated in advance using a setup calculator.

This creates a virtual impact drop in i-stand I that is similar to the impact drop that occurred in stand 5+1. As shown in FIG. 3, the load signal detected by the load cell 11 of the 1.1+1 stand 2 is i-
It is also transmitted to the i1 stand, and a virtual impact effect is also formed on the i1 stand. That is, a virtual impact drop is caused in all the stands upstream of the roaring stand 1, thereby maintaining the uniform speed characteristic of all the stands that are already in a jammed state.

FIG. 4 is a waveform diagram showing the operation of the speed control system of the embodiment shown in FIG. As shown in Fig. 4('b), K, time t
1. ．． When the workpiece 3 is bitten by the 1+1 stand 2, an impact drop of 1 area B occurs. At the same time, as described above, a virtual impact downstairs occurs on the stain stand 1 due to the weighted signal output from the load cell 11. This virtual impact drop is caused by the load cell 11-? This occurs after a certain time delay tl due to a delay in the operation of the current control section 7. However, this time delay t can be reduced to about 510 m5c and can be ignored in practice. , i-stand 1 has area C
Since a virtual impact drop similar to the area B occurs, as shown in Fig. 4 (C), abnormal values will not occur in the inter-stand tension T, making it possible to quickly establish the specified inter-stand tension T. Become.

FIG. 5 shows a second embodiment of the present invention, and the same parts as in FIG. 3 are given the same reference numerals, and the explanation thereof will be omitted. The first embodiment shown in Fig. 3 is a book in which the motor speed is controlled by the armature voltage of the motor, but the second embodiment shown in Fig. 5 is a book in which the motor speed is controlled by controlling the field current of the motor. It controls the For this reason, the field current control section 18, the field thyristor bridge 19, and the external winding 20 are illustrated, which are different from the first embodiment shown in FIG.

Since speed control using field control has a slower response than armature voltage control, the effect of preventing abnormal tension according to the present invention is greater.

As is clear from the above explanation, (1) according to the present invention, a virtual impact similar to the impact drop that occurs on the stand that is bitten by all the stands upstream of that stand is caused by the load signal of the stand in which the workpiece is bitten. Since the drop can be caused, it is possible to prevent an abnormal value from occurring in the inter-stand tension, and it is possible to shorten the time required to establish the specified inter-stand tension. Therefore, if the present invention is applied to, for example, a rolling mill, it becomes possible to reduce the off-gauge at the tip of the rolled material.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the speed control system of a conventional tandem rolling mill, Fig. 2 is a waveform diagram showing the operation of the speed control system of the conventional tandem rolling mill shown in Fig. 1, and Fig. 3 is a waveform diagram showing the operation of the speed control system of the conventional tandem rolling mill shown in Fig. 1. FIG. 2 is a block diagram showing a first embodiment of the invention. FIG. 4 is a waveform diagram showing the operation of the first embodiment shown in FIG. 3, and FIG. 5 is a block diagram showing the second embodiment of the present invention. 1... 1 stand, 2-i+1 stand, 3... Workpiece, 4... Electric motor, 5... Speed detector, 6...
Speed control section, 7... Current control section %8... Firing angle control section, 9... Thyristor bridge, 10... Current detector, 11... Load cell, 12... Load control section ,1
3...Function generator. 14... Multiplier, 15... Impact drop compensation circuit, 16... Speed command unit, 17... Multiplier, 18...
- Field current control unit, 19... Field thyristor bridge, 20... Field winding. Agent Patent Attorney Masami Akimoto Fig. 1 (11th finger 4Σ Bodhisattva) Fig. 3 t (Speed j1% + Kei ν) (IIR
(11 l) Figure 4 is 11

Claims (1)

[Claims] 1. At the time when the workpiece is bitten by the roll of the downstream roll stand, the speed drop that occurs in the electric motor of the downstream roll stand is detected, and the downstream roll where the workpiece is bitten is detected based on the glare detection value. A plurality of roll stands are provided, characterized in that each motor of all the roll stands located upstream of the stand is caused to have a speed drop in phase with the speed drop that occurs in the motor of the downstream roll stand. A method for controlling the motor speed of a processing machine.