JPH05292780A - Bridle roll controller and control method - Google Patents

Abstract

PURPOSE:To prevent slip between a bridle motor(BR) and a sheet material by converting a current detection value of a motor coupled with the BR into tensile force to be produced in the sheet material and then comparing the tensile force thus converted with a predetermined tensile force. CONSTITUTION:A tensile force setting means 11 sets a predetermined tensile force and a tensile force/current converting means 12 converts the tensile force thus set into current value to be fed to motors 58, 59. Current values to be fed to the motors 58, 59 are distributed through an upper/lower roll current distributing means (UD) 13. Outputs from motor current detecting means 34a, 34b are moving averaged within a predetermined time through averaging means 14a, 14b and converted to a tensile force value to be produced in a sheet material. First current control means 15a, 15b compare outputs from the averaging means 14a, 14b with an output from the UD 13 to determine a differential tensile force and a differential stress which are then outputted to PI control means 16a, 16b. Carrying speed of the entire sheet material is set by a carrying speed setting means 18 and the sum of the set carrying speed and the outputs from limiter means 17a, 17b is delivered, as a control target carrying speed, to control circuits 30a, 30b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bridle roll control method for controlling a bridle roll for adjusting the tension generated in a sheet material at the carrying-in side and the carrying-out side when a sheet-shaped material such as a steel plate is conveyed. And a bridle roll control device.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram showing an example of conventional bridle roll control means. In FIG.
The motors 58 and 59 connected to the bridle roll are driven by control circuits 71a and 71b that perform automatic current regulation. Motor 5
The respective current values to be supplied to 8, 59 are the current setting means 72a, 72
The value of each motor current actually flowing through the motors 58 and 59 is set to the motor current detecting means 75a and 75b.
b, and the values of both are detected by the current control means 73a,
73b. Current control means 73a, 73
The output of b is an inverter 74a, which is a motor driving means,
The voltage or current that is input to 74b and is applied to the motors 58 and 59 by the inverters 74a and 74b is controlled by, for example, pulse width modulation (PWM).

With such a configuration, the motors 58, 59
The value of the motor current that actually flows in the current setting means 72a,
If it is larger than the current setting value set in 72b, the motor current value works to decrease, while if the motor current value is smaller than the current setting value, it works to increase the motor current value. As a result, a constant current flows through the motors 58 and 59 regardless of the transport speed.
Therefore, the tension adjustment by the bridle roll is performed by adjusting each current setting value to be supplied to the motors 58 and 59.

FIG. 5 is a block diagram showing another example of the conventional bridle roll control means. In FIG.
The motors 58 and 59 connected to the bridle roll are driven by a combination of automatic tension control (Automatic Tension Regulation) and automatic speed control (Automatic Speed Regulation).

First, a control circuit 90 for performing automatic speed control.
The operations of a and 90b will be described. Current control means 92
a, 92b, inverters 93a, 93b and motor current detection means 94a, 94b perform the same automatic current control as described above, and rotation speed detection means 95a, 95b connected to the motors 58, 59 cause the motor 58,
The respective rotation speeds of 59 are detected, and the conveyance speed control means 91
It is input to one input of a and 91b. A predetermined transport speed value that is a control target value is input to the other input of the transport speed control means 91a and 91b, and the two input values are compared.

With such a circuit configuration, the motor 58,
When the value obtained by converting each rotation speed of 59 into the conveyance speed is higher than the predetermined conveyance speed value, each rotation speed decreases, while the value obtained by converting the rotation speed into the conveyance speed is
When the value is smaller than the predetermined transport speed value, each rotation speed acts so as to increase, and as a result, the motors 58 and 59 are driven at a constant rotation speed.

Next, the operation of the control circuit 80 for performing the automatic tension control will be described. First, the tension detecting means 96 as shown in FIG. 6 is inserted into the carry-in side or the carry-out side of the bridle roll, and the tension actually generated in the steel plate 50 is detected. The tension detecting means 96 is provided with the stress detecting roller 96a displaced between the fixed rolls 97 and 98 slightly above the entire horizontal level, and stresses such as a load cell installed near the bearing of the stress detecting roller 96a. The sensor is configured to detect the stress in the vertical direction.
Therefore, as the tension generated on the steel plate 50 increases, the force in the vertically downward direction acts on the stress detection roller 96a, and the output of the stress sensor increases. Conversely, the tension generated on the steel plate 50 is converted by converting the output of the stress sensor. Can be detected.

The output of the tension detecting means 96 is compared with the output of the tension setting means 81 for setting a predetermined tension value as a control target value, and is input to the tension current converting means 82. The tension converting means 82 outputs a current value to be passed through the motors 58 and 59, corresponding to the input tension value. Next, the current values to be supplied to the upper and lower roll current distribution means 83 and distributed to the motors 58 and 59 are distributed, and the torques to be borne by the bridle rolls are determined.

The respective outputs from the upper and lower roll current distribution means 83 are input to PI control means 84a and 84b where integration processing and multiplication processing are performed, and the following limiter means 85a and 8b are provided.
5b limits the range to a predetermined upper limit value and lower limit value.

On the other hand, the conveying speed setting means 86 includes the steel plate 5
An overall transport speed of 0 is set, and the limiter means 8
The total of the outputs of 5a and 85b is input to each control circuit 90a and 90b that performs automatic speed control.

With the above structure, the tension detecting means 9
When the tension generated on the steel plate 50 in the portion where 6 is provided is larger than the tension value set by the tension setting means 81, the bridle roll conveying speed works so as to decrease, while the tension generated on the steel plate 50 is set. When the tension value is smaller than the above tension value, the bridle roll transport speed acts so as to increase, and as a result, the tension generated in the steel plate 50 in the portion where the tension detecting means 96 is provided becomes constant. Therefore, the tension adjustment with the bridle roll is performed by adjusting the value set in the tension setting means 81.

[0012]

However, the conventional bridle roll control means by automatic current control adjusts the tension of the steel plate by stabilizing the motor current flowing through the motor that drives the bridle roll. When the bridle roll and the steel plate fluctuate in frictional force during the overall acceleration or deceleration, slippage occurs between them and a flaw in the longitudinal direction occurs on the surface of the steel plate.

On the other hand, the conventional bridle roll control means by automatic tension control and automatic speed control adjusts the tension of the steel sheet by stabilizing the tension and the conveying speed of the steel sheet, and therefore accelerates or decelerate the entire steel sheet. At the time of
Even if the frictional force fluctuates between the bridle roll and the steel sheet, the conveyance speed and the tension of the steel sheet are detected, so that slipping between them is eliminated. However, there is a problem in that tension detecting means must be installed separately from the bridle roll, and in particular, when a snout for air shutoff as shown in FIG. If the tension detecting means cannot be installed for the reason, there is a problem that it is impossible to realize the automatic tension control and the automatic speed control.

In order to solve the above-mentioned problems, an object of the present invention is to automatically adjust the tension of a sheet-shaped material such as a steel plate by a bridging roll even if the tension detecting means cannot be installed. It is an object of the present invention to provide a bridle roll control method and a bridle roll control device that exhibit performance equivalent to that of tension control, prevent slippage between a steel plate and a bridle roll, and can perform stable tension control.

[0015]

SUMMARY OF THE INVENTION The present invention stabilizes the motor current by detecting a motor current flowing through a motor for driving a bridle roll, and detects the rotation speed of the motor to detect the motor speed. In a bridle roll control method for stabilizing the conveyance speed of a sheet material conveyed by a roll, by converting a detected value of the motor current into a tension generated in the sheet material, and further comparing it with a preset tension value. The bridle roll control method is characterized in that the conveyance speed is controlled.

Further, according to the present invention, a tension setting means for setting the tension of the sheet material conveyed by the bridle roll, a conveyance speed setting means for setting the conveyance speed of the sheet material, and a motor for driving the bridle roll. A motor driving means for controlling a voltage or a current applied to the motor; a rotation speed detecting means for detecting a rotation speed of the motor; a motor current detecting means for detecting a motor current flowing through the motor; Averaging processing means for moving and averaging the output from the current detecting means within a fixed time, tension current converting means for converting the output from the tension setting means into a current setting value to flow to the motor, the current setting value and the averaging First current control means for comparing the output from the conversion processing means,
Conveyance speed control means for comparing the sum of the output from the first current control means and the output from the conveyance speed setting means with the output from the rotation speed detection means, and the output from the conveyance speed control means The bridle roll control device further comprises a second current control means for comparing the output from the motor current detection means and outputting the result to the motor drive means.

[0017]

According to the bridle roll control method of the present invention,
The motor current is stabilized by detecting the motor current flowing in the motor that drives the bridle roll, and the rotation speed of the motor is detected to stabilize the conveying speed of the sheet material conveyed by the bridle roll, and the motor The tension deviation ΔT (= T1−T2) between the two is calculated by converting the detected value of the electric current into a tension value T1 generated in the sheet-shaped material and comparing it with a preset tension value T2 which is a control target value. The stress deviation Δσ is obtained by dividing the tension deviation ΔT by the cross-sectional area (width × thickness) of the sheet-shaped material, and the elongation deviation Δε required to set the stress deviation Δσ to 0 It is obtained by dividing by the rate E, and the sum of the elongation deviation Δε per unit time and the transport speed set value is the transport speed which is the control target value. Therefore, when the transportation speed of the sheet material is accelerated or decelerated, the transportation speed setting value that determines the transportation speed of the entire steel sheet is also increased or decreased at the same time, so that the tension applied to the sheet material by the bridle roll is accelerated or decelerated. It can be controlled to be constant regardless of steady conveyance. Therefore, it is possible to eliminate the occurrence of slippage between the bridle roll and the sheet-shaped material, which tends to occur when the sheet-shaped material is accelerated or decelerated.

Further, according to the bridle roll control device of the present invention, the motor current flowing through the motor for driving the bridle roll is detected by the motor current detecting means to stabilize the motor current, and the rotation speed of the motor is changed to the rotation speed. The detection speed of the sheet material conveyed by the bridle roll is stabilized by the detection by the detection means, and the detected value of the motor current is converted into the tension value T1 generated in the sheet material by the averaging processing means and further controlled. A tension deviation ΔT (= T1-T2) between the two is calculated by comparing the tension value T2 set in the tension setting means, which is a target value, with the first current control means,
This tension deviation ΔT is the cross-sectional area of the sheet material (width x thickness)
The stress deviation Δσ is obtained by dividing by, and the elongation deviation Δε required to make the stress deviation Δσ zero is obtained by dividing the Young's modulus E of the sheet-like material, and further output from the first current control means. The sum of the elongation deviation Δε per unit time and the transport speed set value set in the transport speed setting means is the transport speed that is the control target value. Therefore, when the transportation speed of the sheet material is accelerated or decelerated, the transportation speed setting value that determines the transportation speed of the entire steel sheet is also increased or decreased at the same time, so that the tension applied to the sheet material by the bridle roll is accelerated or decelerated. It can be controlled to be constant regardless of steady conveyance. Therefore, it is possible to eliminate the occurrence of slippage between the bridle roll and the sheet-shaped material, which tends to occur when the sheet-shaped material is accelerated or decelerated.

[0019]

EXAMPLE FIG. 1 is a schematic configuration diagram showing an example of a continuous plating process in which a bridle roll to which the present invention is applied is used in a steel plate manufacturing process. The continuous plating step is a step of continuously plating a surface of a steel sheet, which is a sheet-like material, with a metal such as zinc or aluminum. In FIG. 1, the steel sheet 50 has three bridle rolls 51, 52,
It is sent at a constant carrying speed by the roll carrying unit A constituted by 53 and carried into a pretreatment furnace 54 such as an oxidation-reduction annealing furnace. In the pretreatment furnace 54, the steel sheet 50 is annealed and the oxide film on the surface is reduced, and pretreatment for plating is performed.

The steel plate 50 carried out from the pretreatment furnace 54 is
After passing through the bridle rolls 56 and 57 for tension adjustment, the metal 6 such as zinc or aluminum is passed through the dipping roll 62.
1 is immersed in the molten plating bath 60. In addition, the path conveyed from the pretreatment furnace 54 to the plating tank 60 is cut off from the atmosphere by using a snout 55, and
Oxidation of 0 is prevented. The steel plate 50 carried out from the plating tank 60 receives a high-pressure gas jet from the wiping nozzle 63, and the amount of plating adhered to the surface is adjusted.

Since the steel plate 50 immediately after plating is in a high temperature state, the top rolls 64 and 65 and the deflector roll 66 are
Cooled in the process of passing through the four bridle rolls 6
It is sent at a constant transport speed by the roll transport unit B composed of 7, 68, 69 and 70, passes through a temper rolling mill, a tension leveler, a post-treatment tank, etc. in the subsequent stage, and the continuous plating process is completed. ..

In the above steps, the conveying speed of the steel sheet 50 is kept constant in any path. However, in the pretreatment furnace 54, when the steel sheet 50 is heated and the plasticity becomes large and the tension is too large, It is necessary to maintain an appropriate tension because it breaks in the furnace and shrinks in width and thickness due to plastic deformation. The steel plate 50 between the bridle rolls 56 and 57 and the roll transfer unit B is connected to the roll transfer unit A so that the plating thickness does not become non-uniform in the vicinity of the wiping nozzle 63 due to the influence of vibration and corrugation of the steel plate 50. It is necessary to set the tension higher than that of the steel plate 50 between the bridle rolls 56 and 57.

FIG. 2 shows a bridle roll 5 for tension adjustment.
6 and 57, FIG. 2 (a) is a schematic front view thereof, and FIG. 2 (b) is a schematic side view thereof. The bridle rolls 56, 57 have a cylindrical shape that is longer than the width of the steel plate 50, and are arranged in parallel with each other through a gap through which the steel plate 50 passes. The rotating shafts of the bridle rolls 56 and 57 are connected to the motors 58 and 59 via reduction gear mechanisms 56a and 57a such as gears.

In FIG. 2 (b), the steel plate 50 is horizontally carried into the bridle roll 56, and after being brought into contact with the circumference corresponding to the angle θa around its center, it is carried diagonally into the next bridle roll 57. , Contact with the circumference corresponding to the angle θb around its center.

The tension of the steel plate 50 is adjusted within a range in which the steel plate 50 is not plastically deformed, for example, the transport speed of the roll transport unit A and the roll transport unit B is 100 m / min, and the transport speed of the bridle rolls 56 and 57 is 99.5 m. / Min, and the conveying speeds of the bridle rolls 56 and 57 are set to slightly increase or decrease with respect to the entire conveying speed.

The tension on the loading side of the bridle roll 56 is T
Letting a be T, the tension on the unloading side of the bridle roll 57 be Tb, and the friction coefficient between the steel plate 50 and the bridle rolls 56, 57 be μ, Ta = Tb × EXP [μ (θa + θ
b)] is established. Therefore, the larger the angles θa and θb with which the steel plate 50 contacts the bridle rolls 56 and 57, or the larger the friction coefficient μ, the wider the adjustable range of tension.

The bridle roll for adjusting the tension as described above is not limited to the continuous plating process, but also includes a hot rolling process, a cold rolling process, a continuous pickling process, an electrolytic cleaning process, a temper rolling process, and a continuous rolling process. It can be used in various processes such as an annealing process, a continuous electroplating process, a vacuum deposition plating process, a continuous coating process and the like. Further, the number of bridle rolls for adjusting the tension may be one or three or more as required.

FIG. 3 is a block diagram of a bridle roll controller which is an embodiment of the present invention. In FIG.
The motors 58 and 59 connected to the bridle roll are directly driven by the control circuits 30a and 30b such as vector controllers that perform automatic speed control.
The transport speed values input to 0a and 30b are those obtained by correcting the transport speed set value of the entire sheet-shaped material such as a steel plate by a moving average of the motor current value flowing in the motor within a fixed time. It

First, a control circuit 30 for automatic speed control
The operations of a and 30b will be described. Second current control means 32a, 32b, inverter 33 which is a motor drive means
a, 33b and motor current detection means 34a, 34b perform automatic current control similar to the conventional one, and rotation speed detection means 35a, connected to the motors 58, 59.
The rotation speeds of the motors 58 and 59 are detected by 35b and input to one input of the conveyance speed control means 31a and 31b. A predetermined transport speed value that is a control target value is input to the other input of the transport speed control means 31a and 31b, and the two input values are compared.

With this circuit configuration, the motor 58,
When the value obtained by converting each rotation speed of 59 into the conveyance speed is higher than the predetermined conveyance speed value, each rotation speed decreases, while the value obtained by converting the rotation speed into the conveyance speed is the predetermined conveyance speed. When it is smaller than the speed value, each rotation speed acts so as to increase, and as a result, the motors 58 and 59 are driven at a constant rotation speed.

Next, such control circuits 30a and 30b
Control circuit 10 such as a sequencer for instructing the conveyance speed value to the
The operation will be described. First, a predetermined tension value as a control target value is set in the tension setting means 11, and the tension / current converting means 12 converts it into a current value to be passed through the motors 58 and 59. Next, the current value that is input to the upper and lower roll current distribution means 13 and distributed to the motors 58 and 59 is distributed, and the torque that each bridle roll bears is determined.

On the other hand, motor current detection means 34a, 34b
The respective outputs from are input to the averaging processing means 14a and 14b, moving averaged within a fixed time, and converted into a tension value T1 generated in the sheet material.

The moving average is to integrate an input signal in a constant time range from time t0 to time t1 and divide by the constant time which is an integration range. By moving the integration range with time. , Has a function of smoothing the original input signal. When this moving average is digitally processed using a computer or the like, the input signal is sampled at regular intervals and converted into a discrete input signal, and then the total sum is obtained within a constant time period from time t0 to time t1. , And has a function of smoothing the original input signal by moving the time range obtained by dividing by the number of samplings within the range and summing with the passage of time.

The first current control means 15a and 15b compare the respective outputs of the averaging processing means 14a and 14b with the respective outputs of the upper and lower roll current distribution means 13 to determine the tension value T1 generated in the sheet material, Further, the tension deviation ΔT (= T1) from the preset tension value T2 which is the control target value
-T2) is obtained, and the stress deviation Δσ is calculated by dividing the tension deviation ΔT by the cross-sectional area (width × thickness) of the sheet-shaped material, and the elongation deviation Δε required to make the stress deviation Δσ zero. The sheet-shaped material is divided by the Young's modulus E to obtain it and output to the PI control means 16a and 16b in the next stage.
When converting the tension deviation ΔT into the stress deviation Δσ, the actual cross-sectional area may be divided by a value obtained by multiplying the correction coefficient by the correction coefficient.

The PI control means 16a and 16b perform integration processing and multiplication processing of the input signal, and the next limiter means 1
7a and 17b limit the range to a predetermined upper limit value and lower limit value.

On the other hand, the transport speed of the entire sheet material is set in the transport speed setting means 18, and the limiter means 17 is set.
The outputs from a and 17b, that is, the sum of the elongation deviation Δε per unit time is input to each control circuit 30a and 30b that performs automatic speed control as the conveyance speed that becomes the control target value.

With the above-mentioned structure, when the conveying speed of the sheet material is accelerated or decelerated, the conveying speed set value of the entire sheet material is also increased or decreased at the same time, so that the bridle roll acts on the sheet material. Since the tension can be controlled to be constant irrespective of acceleration / deceleration or steady conveyance, slippage between the bridle roll and the sheet-shaped material, which tends to occur particularly during acceleration / deceleration, can be eliminated. Moreover, since it is not necessary to separately install tension detecting means for detecting the tension generated in the sheet-shaped material,
The present invention is particularly useful when the space before and after the bridle roll is narrow, for example, when the snout is installed from the heating furnace of the continuous plating process to the plating tank as shown in FIG.

In the above embodiments, an example in which the number of bridle rolls for tension adjustment is two has been described, but a configuration having one bridle roll or three or more bridle rolls can be similarly applied.

[0039]

As described in detail above, according to the present invention,
Since the detected value of the motor current flowing through the motor connected to the bridle roll is converted into the tension generated in the sheet-shaped material and compared with the preset tension value, the conveyance speed that is the control target value is controlled. While stably applying a predetermined tension to the sheet-shaped material, it is possible to prevent slippage between the bridle roll and the sheet-shaped material, which is likely to occur when the sheet-shaped material is accelerated or decelerated, and reduce the occurrence of flaws due to slippage. be able to.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an example of a continuous plating process in which a bridle roll to which the present invention is applied is used in a steel plate manufacturing process.

2 shows bridle rolls 56 and 57 for tension adjustment, FIG. 2 (a) is a schematic front view, and FIG.
(B) is a schematic side view.

FIG. 3 is a block diagram of a bridle roll control device according to an embodiment of the present invention.

FIG. 4 is a block diagram showing an example of a conventional bridle roll control means.

FIG. 5 is a block diagram showing another example of conventional bridle roll control means.

FIG. 6 is a schematic configuration diagram of a tension detecting means 96.

[Explanation of symbols]

 10 Control Circuit 11 Tension Setting Means 12 Tension Current Converting Means 13 Vertical Roll Current Distributing Means 14a, 14b Averaging Processing Means 15a, 15b First Current Control Means 16a, 16b PI Control Means 17a, 17b Limiter Means 18 Conveying Speed Setting Means 30a , 30b Control circuits 31a, 31b Conveyance speed control means 32a, 32b Second current control means 33a, 33b Inverters 34a, 34b Motor current detection means 35a, 35b Rotation speed detection means 58, 59 Motor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H02P 5/46 H 9063-5H

Claims (2)

[Claims] 1. A sheet material conveyed by the bridle roll by stabilizing the motor current by detecting a motor current flowing through a motor for driving the bridle roll, and by detecting a rotation speed of the motor. In the bridle roll control method for stabilizing the conveyance speed, the control value is controlled by converting the detected value of the motor current into a tension generated in the sheet-shaped material and further comparing it with a preset tension value. And a bridle roll control method. 2. A tension setting means for setting a tension of a sheet material conveyed by a bridle roll, a conveyance speed setting means for setting a conveyance speed of the sheet material, a motor for driving the bridle roll, and Motor drive means for controlling the voltage or current applied to the motor, rotation speed detection means for detecting the rotation speed of the motor, motor current detection means for detecting the motor current flowing in the motor, and the motor current detection means Averaging processing means for moving and averaging the output from the device within a fixed time, tension current converting means for converting the output from the tension setting means into a current setting value to flow to the motor, the current setting value and the averaging processing means And a sum of an output from the first current control means and an output from the transport speed setting means, Conveyance speed control means for comparing the output from the rotation speed detection means, and a second current for comparing the output from the conveyance speed control means with the output from the motor current detection means and outputting to the motor drive means. A bridle roll control device comprising: a control means.