JPS63115615A - Tension control method for strip and tension calculating device - Google Patents

Abstract

PURPOSE:To improve the responsibility in control and to prevent the generation of the fastening and loosening in winding by feeding back the load torque calculated by a calculated tension to a motor torque and controlling the current of a motor so as to conform the calculated tension to a tension command value. CONSTITUTION:The tension command signal inputted inputted to a motor current controller 7 is decided at a tension command part 8. The tension command part 8 is composed by a tension calculation device 10, tension setter 11, two adders 8a, 8b and tension control device 8c, and the tension command vlaue set at the tension setter 11 is given to the adders 8a, 8b. In the adder 8a, the deviation in the tension calculation value of the output of the tension calculation device 10 and the tension command value is calculated, the deviation is added to the tension command value in the adder 8b via the tension control device 8c, the new tension command value is made and inputted to the motor current control part 7.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a tension control method for a strip to be wound under a predetermined tension, such as in the production of cold-rolled steel sheets, and a tension calculation device used therefor. Regarding.

[Prior art]

In temper rolling mills, reverse cold mills, and the like in the manufacturing process of cold-rolled thin steel sheets, managing the tension of the rolled material is an important issue in terms of quality control of the rolled material.

For example, in a temper rolling mill, when a rolled material is wound up or unwound on a take-up reel or an unwinding reel, the tension of the rolled material fluctuates, causing tightening or loosening of the rolled material.
For this reason, there is a risk that surface flaws may occur in the rolled material or the winding shape may deteriorate.In addition, in reverse cold mills, the thickness of the rolled material is controlled by controlling its tension, which results in a uniform plate. In order to manufacture thick steel plates, it is necessary to keep the tension of the rolled material constant during rolling.

Conventionally, two methods have been used to control the tension of rolled materials in temper rolling mills and reverse cold mills.
The second method is to control the current of the drive motor for the take-up reel and/or unwinding reel of the rolled material based on the tension command value set by the tension setting device. The tension of the motor is actually measured, and the current of the motor is controlled so that the measured tension matches the tension command value.

FIG. 4 is a schematic diagram showing the implementation state of the first method in the tension control system of a temper rolling mill. In the figure, 1 is the stand of the temper rolling mill, 2 is the rolled material, and 4.5 is the rolled material 2.
These are a rewind reel and a take-up reel for rewinding and rewinding, and the reels 4 and 5 are each driven by a reel drive motor 6.
．． 6' to wind up the rolled material 2. Further, 6b is a power supply section of the reel drive motor 6, and 6b is a power supply section of the reel drive motor 6.
The torque Td generated by is proportional to the field magnetic flux Φ generated in the field 6a of the motor by the field current I supplied from the power source 6b and the armature current 3, and is determined by the following equation.

T, = ΦI8 (1) However, K is a constant specific to the motor. On the other hand, if the tension occurring in the rolled material 2 is F, then the tension F
acts on the rotating shaft of the reel drive motor 6 via the unwinding reel 4 as a load torque Tno determined by the following equation.

T, = F-D C/2 - (2) However, DC is the outer diameter of the rolled material 2 being rewound on the unwinding reel 4. In a steady state, the torque T generated by the reel drive motor 6 is
4 and the load torque Tt are equal, so the formula (1) is as follows: In order to keep the tension F acting on the rolled material 2 constant, keep the armature current in the reel drive motor 6 constant, It is only necessary to change the field magnetic flux Φ so that the ratio of this to the outer diameter DC of the rolled material 2 wound on the unwinding reel 4 is constant.

The armature current (2) and field current (5) supplied from the power supply section 6b to the reel drive motor 6 are controlled based on the signal given from the motor current control section 7, which is shown enclosed by a two-dot chain line in FIG. ing.

The motor current control unit 7 receives the outputs of a motor rotation speed detector 6c and a roll rotation speed detector 9a, each using a pulse generator, which are attached to the reel drive motor 6 and the deflation crawler 9, respectively, and the tension setting device 11. The output is given. Coil diameter calculation unit 7 of motor current control unit 7
a is the outer diameter of the rolled material 2 wound into a coil in the unwinding wheel 4 from the rotational speed of the reel drive motor 6 and the declef crawler 9 given from both the rotational speed detectors 6c and 9a. DC is calculated, and a signal corresponding to the calculated outer diameter DC is input to the field calculation section 7b and the acceleration/deceleration compensation section 7c. The field calculation unit 7b calculates the above-mentioned field magnetic flux Φ and outer diameter from the input signal corresponding to the outer diameter DC.

The field magnetic flux φ to be given to the field 6a based on the relationship with
is calculated, and a signal corresponding to the calculated field magnetic flux φ is manually inputted to the field current control section 7d. The field current control unit 7d calculates the field current 5 to be supplied to the field 6a of the reel drive motor 6 based on the signal corresponding to the inputted field magnetic flux Φ, and outputs a signal corresponding to this. is input to the power supply section 6b.

In this way, the field current of the field 6a of the reel drive motor 6 is
, are controlled so that the ratio between the outer diameter DC and the field VA magnetic flux Φ is always constant.

On the other hand, the acceleration/deceleration compensation section 7c includes a line speed change rate calculation section 7e that calculates the rate of change in the line speed of the rolled material 2 from the output of the roll rotation speed detector 9a as well as the output of the coil diameter calculation section 7a. From these outputs, the acceleration/deceleration compensator 7c calculates the tension F' applied to the rolled material 2 due to the inertia of the coil during acceleration/deceleration, and provides a signal corresponding to this to the adder 7f. In the adder 7f, the tension command value F r from the tension setting device 11 is added to the additional tension F'.
af is added, and the total value is input to the armature current control section 7g, where the adder 7
Armature current (1) to be supplied to the reel drive motor 6 is calculated based on the signal input from f, and a signal corresponding to this is input to the power supply section 6b.

As described above (armature current I of the reel drive motor 6).

The tension of the rolled material 2 is controlled by controlling the field current I and the field current I. Similar current control is also performed in the reel drive motor 6' of the take-up reel 5.

In the second method, as shown in FIG. 5, a tension roll 20 is provided between the stand 1 and the deflation crawler 9, and the tension roll 20 rolls into contact with the rolled material 2 from the lower surface side while pushing it up. Load cell 2 transfers the downward load acting on the bearing.
0a, the detected value is given to the adder 22 as a signal corresponding to the tension F acting on the rolled material 2 via the tension conversion section 21, and in the adder 22, the tension setting device 1
Deviation Δ between the tension command value F rat from 1 and the tension F
Then, the deviation ΔF is added to the tension command value Fraf in the adder 23 via the tension control unit 24 to obtain a new tension command value F, . , ' and are given to the motor current control unit 7, which was detailed in the first method.

That is, the actual measured value of the tension F of the rolled material 2 determined from the detected value of the load cell 20a is given as a correction value for the tension command value F rtaf set by the tension setting device 11, and the tension command value F ref and the tension F The deviation from the actual measured value is 0.
The armature current I and field current I of the reel drive motor 6 are controlled so that.

[Problem that the invention seeks to solve]

The conventional tension control method for rolled materials as described above has the following drawbacks. That is, in the first method, the absolute value of the tension acting on the rolled material during rolling is unknown, which is inconvenient in terms of operational management, and when this method is applied to a reverse cold mill, the tension There was a problem in that the responsiveness to the tension command from the tension setting device when changing settings was extremely poor, and this hindered improvement in plate thickness accuracy.

In the second method, the tension of the rolled material is actually measured and this is used as a feedback signal for the tension command value, so it seems that the above-mentioned difficulty has been solved, but in reality, this problem is not solved. The detected tension value from a tension roll such as
It contains considerable fluctuation components due to various errors such as noise caused by vibrations of the supporting base and errors caused by differences in plate thickness and yield stress in each part of the rolled material, and this fluctuation actually affects the rolled material. It is not possible to determine whether the cause is due to tension fluctuations occurring in the tension command or the noise and error mentioned above, and if a filter is used to remove the noise, the response will decrease and the tension command The reality is that it cannot be used as a correction signal for the value.

In addition, the provision of tension rolls has the disadvantage that the sheet threading workability is reduced, and furthermore, there is a risk of scratches on the surface of the rolled material due to contact with the rolls, and maintenance of the rolls is troublesome. .

These difficulties are not limited to the rolling process, but also to recoil lines in electrolytic cleaning processes, inspection processes, etc.
This problem occurs not only in the manufacturing process of the lli4 board but also when the strip is wound up with a predetermined tension.

The present invention has been made in view of the above circumstances, and it is possible to calculate the tension acting on the strip with high precision based on the detected value of a physical quantity that can be detected with high precision, and it also facilitates maintenance management. We provide a tension calculation device that eliminates the need for
By applying this to the strip tension control system, it is an object of the present invention to provide a strip tension control method that can improve control responsiveness and prevent the occurrence of tight winding and loose winding.

[Means for solving problems]

The tension control method for a strip according to the present invention includes a winding reel and/or an unwinding reel for the strip in order to perform winding/rewinding while making the tension acting on the strip match a preset tension command value. In a strip tension control method that controls the current of a drive motor, the rotational speed of the motor is calculated based on the detection results of the current of the motor and the winding and unwinding speeds of the strip, and this calculated value and the corresponding Based on the result of comparison with the detected value of the rotational speed of the motor, the tension acting on the strip is calculated, the load torque applied to the motor is calculated from this calculated tension, and this calculated value is used when calculating the motor rotational speed. The tension calculation device of the present invention is characterized in that the current of the motor is controlled so as to feed back the motor torque of the strip and to make the calculated tension coincide with the tension command value. A drive torque calculation unit that calculates the drive torque of the motor based on detected values of armature current and field current supplied to the rewind reel drive motor, and calculation of the drive torque calculated by the calculation unit. a rotational speed calculation unit that calculates the rotational speed of the motor based on the rotational speed; and a rotational speed calculation unit that calculates the rotational speed of the motor based on the deviation of the rotational speed calculated by the calculation unit and the detected rotational speed of the motor. a tension calculation unit that calculates the tension acting on the motor; and a tension calculation unit that calculates the load torque applied to the motor by the tension based on the calculated value of the tension calculated by the calculation unit, and feeds back this calculation result. The present invention is characterized by comprising a load torque calculation section that provides a signal to the rotational speed calculation section.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on drawings showing embodiments thereof. Figure 1 shows a strip tension control method according to the present invention in a tension control system of a temper rolling mill (hereinafter referred to as the present invention method).
It is a schematic diagram showing the implementation state of. In the figure, l is a stand of the skin pass rolling mill, 2 is a rolled material, and the rolled material 2 is carried into the rolling mill entrance side by a coil conveyor 3 in a coiled state, and is transferred to an unwinding reel 4. It is attached between the winding reel 5 and the winding reel 4 and the winding reel 5, and is temper-rolled between the rolling rolls la and lb of the stand l while winding and unwinding the winding 9 by the rotation of the unwinding reel 4 and the winding reel 5. Further, 6 is a reel drive motor for driving the rewind reel 4, and this motor 6 is connected to a power supply section 6b.
An output signal from the motor current control section 7 is given to b.

The motor current control unit 7 has the same configuration as the motor current control unit 7 in the first conventional method described above (see FIG. 4), and is attached to the rotating shaft of the reel drive motor 6 to control the motor 6. A motor rotation speed detector 6c using a pulse generator, for example, outputs No. 13 N corresponding to the rotation speed, and is attached to the rotation shaft of the deflation crawler 9 and outputs a signal n corresponding to the rotation speed of the roll 9. , Armature current ■1 to be supplied to the reel drive motor 6 in order to wind the rolled material 2 under a predetermined tension based on an input signal from the roll rotation speed detector 9a using a pulse generator, for example. and field current 1b are calculated, and signals corresponding to these are input to the power supply unit 6b and a tension calculation unit 10, which will be described later. The power supply unit 6b supplies an armature current I and a field current I to the reel drive motor 6 based on the signal input from the motor current control unit 7, and
is the field 6fH generated in the field 6a by the field current ■.
ft flux Φ and armature current 1. The rewind reel 4 is rotated by generating a torque T4 proportional to the rewind reel 4.

Now, the tension command signal input to the motor current control section 7 is determined by the tension command section 8. The tension command unit 8 is
The tension calculating device 10 according to the present invention, a tension setting device 11, is composed of two adders 8a, 8b, and a tension control device 8c, and the tension command value F1. ．． are given to adders 8a and 8b.

In the adder 8a, the deviation ΔF between the tension calculation value F'', which is the output of the tension calculation device 10, and the tension command value F, . . . is calculated, and the deviation ΔF is added via the tension control device 8c. In the device 8b, the tension command value F ref is added to the tension command value F ref and the new tension command value F r*f' is inputted to the motor current control section 7. That is, the tension calculation value !10 is added to the tension command value F ref in the conventional second method. It replaces the tension conversion unit 21, and in the method of the present invention, the tension calculation unit 1 is used instead of the measured tension F determined from the detected value of the load cell 20a.
The tension command value F ref from the tension setting device 11 is corrected using the tension calculation value F1 which is an output of zero.

- The reel drive motor 6' of the thick take-up reel 5 is also provided with a motor current control section and a tension calculation device (not shown) that have the same configuration as the motor current control section 7 and tension calculation device IO, respectively.

The tension calculation device 10 receives a signal N corresponding to the rotation speed of the reel drive motor 6 from the motor rotation speed detector 6C, and a signal N corresponding to the rotation speed of the deflation crawler 9 from the roll rotation speed detector 9a, that is, the line speed of the rolled material 2. A signal n corresponding to the armature current (2) and a field current (2), which are supplied to the reel drive motor 6 as described above, are respectively inputted, and a signal i corresponding to the field current (2) is input.

and i are input. The tension calculation device 10 simulates a mechanism in which tension F is generated in the rolled material 2 by the rotation of the reel drive motor 6, and the tension calculation device 10 simulates the mechanism in which tension F is generated in the rolled material 2 by the rotation of the reel drive motor 6.
A tension calculation value F0 is calculated from r i@, 1b, and is provided to the adder 8a, and is also output to the display section 10a and displayed on the display section 10a.

FIG. 2 is a block diagram showing the configuration of the tension calculation device 10.

First, tension F is applied to the rolled material 2 by the rotation of the reel drive motor 6.
The mechanism by which this occurs will be explained. Reel drive motor 6
When the armature current (2) and the field current (2) are supplied from the first source 6b to the motor 6, the motor 6 generates the driving torque T4 shown by the above equation (1).

T, = Φ■1...(1) However, φ is the field magnetic flux generated in the field 6a when the field current Ib is supplied, and the tension F generated in the rolled material 2 is the unwinding reel 4.
A load torque Tj expressed by the above equation (2) is applied to the reel drive motor 6 via the equation (2).

However, DC is the outer diameter of the rolled material 2 wound on the unwinding reel 4, and the difference between the drive torque T6 and the load torque T. Since the rotating part made of the material 2 is accelerated or decelerated, the rotational speed N of the rotating part is, where J is the moment of inertia of the rotating part. The rolling speed V of the rolled material 2 is determined by this rotational speed N and the outer diameter DC as follows: ■=πDcN (5), and the tension F generated in the rolled material 2 is determined by this rolling speed V,
Tension change rate G (
V, σ) multiplied by the cross-sectional area A in the direction perpendicular to the moving direction of the rolled material 2.

F=G (V, σ)・A (6) Then, the tension F generated in this way applies a load torque T to the reel drive motor 6 as shown in equation (2), and the load torque T
The reel drive motor 6 operates as a feedback signal to the drive torque T4 of the motor 6, and the reel drive motor 6 rotates while maintaining a state in which the deviation between T4 and T4 is zero.

The tension calculation value R10 is calculated using G, the drive torque calculation unit 12 which is a proportional element having a transfer function of 31, and the rotational speed calculation unit 13 which is an integral element which has a transfer function of Gz(S).
Consisting of a tension calculation section 14 which is a proportional element having a transfer function of 0ff(S), a load torque calculation section 15 which is a proportional element having a transfer function of Ga(St), a multiplier 16, and two adders 17 and 18. The input signal t@, lb from the motor current control section 7 is given to the multiplier 16,
They are multiplied by each other and input to the drive torque calculation section 12.

The drive torque calculation section 12 calculates the drive torque Td'' from the human power signals i and xib, and provides this to the adder 17.The transfer function G, (S) of the drive torque calculation section 12 is the is a constant K+, which is obtained by multiplying the constant K in equation (1), which is the value of , by the conversion coefficient from 11 to ■, and the conversion coefficient from ib to Φ.The adder 17
In, T, * which is the output of the driving torque calculation unit 12
The deviation ΔT'' between the calculated value T7''' of the load torque, which is the output of the load torque calculation section 15, is determined and inputted to the rotational speed calculation section 13.

The transfer function 02(S) of the rotation speed calculation unit 13 is Gz (
S)=1/Js (7). However, J is the moment of inertia of the rotating part consisting of the reel drive motor 6, the unwinding reel 4, and the rolled material 2 wound on the reel 4, and is calculated from the motor rotation speed detector 6c and the roll rotation speed detector 9a. It is a value calculated from each input signal N and n, and S is a Laplace operator. That is, the rotational speed calculation unit 13 simulates equation (4), and its output is the calculated rotational speed value N1 of the reel drive motor 6. The output N9 of the rotational speed calculation section 13 is given to the adder 18, and in the adder 18, the deviation from the actual rotational speed N of the reel drive motor 6 inputted from the motor rotational speed detector 6c is used for tension calculation. 14.

The tension calculation unit 14 calculates the rolled material 2 from the input (N''-N).
The tension force F acting on the and input it to the display section 10a.Tension calculation section 1
4 transfer function G, (31 is, where J is the above-mentioned moment of inertia, D is the outer diameter of the rolled material 2 wound on the unwinding reel 4, and the motor rotation speed detector 6c and This is a value calculated from signals N and n input from the roll rotation speed detector 9a.

The load torque calculation section 15 inputs the tension calculation value F'', which is the output of the tension calculation section 14, and receives the load torque calculation value T!''.
is calculated and given to the adder 17 as a feedback signal.

The transfer function G15) of the load torque calculation unit 15 is G15l
=DC/2-(9), and the load torque calculation unit 15 simulates equation (2).

Now, the tension calculation value F''', which is the output of the tension calculation device 10 configured as described above, is the tension F that actually acts on the rolled material 2.
It is shown below that it is equivalent to

The armature current supplied to the reel drive motor 6 is ■1
, the field 6a of the motor 6 [magnetic flux is Φ, and the tension of the rolled material 2 is F, the rotational speed of the reel drive motor 6 is (
From equations 11, (2), and (3), however, Ta- has Φ■
.

becomes. On the other hand, the rotational speed calculation value N" calculated by the tension calculation device 10 at this time is N"=(Ta"-T)") Gz tsl from the relationship between the input and output in the rotational speed calculation section 13. In addition, the tension calculation value F1 becomes F"= Gz (31 (N" N) J from the relationship between the input and output in the tension calculation unit 14. Substituting the 00 formula into the hitting formula, it becomes If we rearrange it, we get: Next, by substituting the α0 formula into the αa formula and taking into account that T4° and Td are clearly the same, we get 2 Js, /s 1+KO/S = F... αω
1+□s K.

becomes.

In formula 051, F″′ is the tension F that actually acts on the rolled material 2.
is passed through a filter with a time constant of 1/0. On the other hand, 0 is a constant that can be set arbitrarily, and if Ko is set to a sufficiently large value, the influence of the filter can be eliminated, and it can be said that F and F'' are equivalent.

As described above, the tension calculation device 10 includes the motor rotation speed detector 6
c, roll rotation speed detector 9a and reel drive motor 6
The tension F acting on the rolled material 2 can be calculated with high precision and without time delay from the respective detected values of the armature current 11 and the field current I applied to the rolling material 2.

Finally, in the tension control system of the reverse cold mill to which the method of the present invention was applied, the tension setting value was changed from 57 on to 6 T.
FIG. 3 shows the experimental results when the power was turned on in a stepwise manner. Further, FIG. 6 shows the results of a similar experiment conducted using the first conventional method, that is, the tension control system shown in FIG. 4.

The experimental conditions are as follows.

Winding plate thickness: 0.5 mm Rolling speed: 900 m/min Coil diameter: 1.5 m In the conventional tension control method shown in Fig. 6, 5 To
The armature current of the reel drive motor has a time constant of 0.05 se for a step change in the tension setting value from n to 6 Ton.
The tension of the rolled material changes as a first-order lag system of about
In the case shown in the figure, in response to a step change in the tension setting value, the electron current of the reel drive motor rises rapidly until it reaches about three times the required increase, and the tension of the rolled material increases to 5.
The time required to change from ton to 6 ton is 0.
It is clear that the response time has been significantly improved.

In this example, the case where the method of the present invention is applied to a tension control system for rolled material in a temper rolling mill is explained, but the present invention can be applied to any tension control system that operates to wind a strip at a predetermined tension. It goes without saying that the invented method is applicable.

〔effect〕

As detailed above, in the method of the present invention, the tension acting on the strip is calculated with high precision and without time delay, and tension control is performed to match this calculated value with the tension setting value, so the responsiveness is improved. This is greatly improved and the absolute value of the tension is displayed, which is very advantageous in terms of operational management, and it is possible to prevent the occurrence of tightening or loosening of the strip.

In fact, since the tension calculation device according to the present invention does not require maintenance, it has the same effect as that of making it possible to significantly shorten the time required for maintenance and management of the tension control system.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the implementation state of the method of the present invention in the tension control system of a skin pass rolling mill, Fig. 2 is a block diagram of the tension calculation device according to the present invention, and Fig. 3 is a tension control system according to the method of the present invention. 4 and 5 are schematic diagrams of the conventional tension control method, and FIG. 6 is a graph showing the response in the tension control system of FIG. 4. DESCRIPTION OF SYMBOLS 1... Stand 2... Rolled material 4... Unwinding reel 5... Take-up reel 6... Reel drive motor 7... Motor current control section 10... Tension calculation device 1
1... Tension setting device 12... Drive torque calculation unit 13
... Rotation speed calculation section 14 ... Tension calculation section 15 ...
・Load torque calculation unit patent Applicant Sumitomo Metal Industries Co., Ltd. Agent Patent attorney Noboru Kono Figure 1 Figure 6

Claims (1)

[Claims] 1. A motor for driving a take-up reel and/or an unwind reel of the strip in order to perform winding/unwinding while making the tension acting on the strip match a preset tension command value. In the strip tension control method for controlling the current of the motor, the rotation speed of the motor is calculated based on the detection results of the current of the motor and the winding/unwinding speed of the strip, and this calculated value and the rotation of the motor are calculated. Based on the comparison result with the detected speed value, the tension acting on the strip is calculated, the load torque applied to the motor is calculated from this calculated tension, and this calculated value is used as the motor torque when calculating the motor rotation speed. 1. A strip tension control method, comprising: feeding back the calculated tension to the tension command value, and controlling the current of the motor so as to make the calculated tension coincide with the tension command value. 2. A drive torque calculation unit that calculates the drive torque of the motor based on the detected values of the armature current and field current supplied to the motor for driving the take-up reel and/or the rewind reel of the strip; a rotational speed calculation unit that calculates the rotational speed of the motor based on the calculated value of the driving torque calculated by the calculation unit; a tension calculation unit that calculates the tension acting on the strip based on the deviation from the detected value;
a load torque calculation unit that calculates a load torque to be applied to the motor due to the tension based on the calculated value of the tension calculated by the calculation unit, and provides the calculation result to the rotational speed calculation unit as a feedback signal; A strip tension calculation device comprising: