JPH05748A - Tension control device - Google Patents

Abstract

(57) [Summary] [Purpose] To reduce the decrease in web tension at the end of acceleration and at the start of deceleration. [Structure] When performing feedback control so as to reduce the deviation between the measured value and the target value of the belt-shaped body unwound from the roll, the target value is increased by a predetermined amount for a predetermined time at the end of acceleration and the start of deceleration. Alternatively, the bias is added to or subtracted from the output at the end of acceleration and the start of deceleration, or the gain of the control system is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tension control device for controlling the tension of a belt-like body unrolled from a roll.

[0002]

2. Description of the Related Art When a web-shaped member such as a web wound on a roll is unwound, a method of controlling the braking force of a brake for braking the rotation of the roll is used in order to unwind the web with a constant tension.

FIG. 8 is a diagram showing an example of such a tension control device. In the figure, 1 is a web, 2 is an unwinding roll that unwinds the web, 3 is a brake that brakes the rotation of the unwinding roll 2, 4 is a guide roll, 5 is a tension detector that detects the tension of the web 1, and 6 Is the brake 3 so that the deviation between the tension detected by the tension detector 5 and the target value becomes zero.
Is a controller for controlling.

FIG. 9 is a block diagram showing the configuration of the controller 6. 61 is an amplifier that amplifies the output of the tension detector 5, 62 is a tension setting device that sets the target tension, 63 is a deviation circuit that takes the difference between the target tension and the detected tension, and 64 is this deviation circuit 63
Is a calculation circuit for performing a control calculation of the deviation of PI / PID, etc., and outputting it to the brake 3.

Next, the operation of the controller 6 shown in FIG. 9 will be described. A deviation circuit 63 compares the detected tension with the target tension to obtain the deviation. The arithmetic circuit 64 performs control calculation of PI / PID and the like to change the operation output so that this deviation becomes zero.

When the unwinding roll 2 as shown in FIG. 8 is accelerating or decelerating, the tension acting on the web 1 is related to the acceleration and the unwinding diameter of the unwinding roll 2 in addition to the brake torque τ _B. Inertia torque τ _AC works. The influence of the inertia torque on the web tension is as follows in each case of acceleration and deceleration. In any case, the change in the unwinding diameter during acceleration / deceleration is ignored, and the torque due to mechanical loss is assumed to be zero.

When the tension during acceleration is balanced with the target tension T, the following equation holds. T · D / 2 = τ _B ′ + τ _AC (1) where τ _B ′ is the braking torque during acceleration, τ _AC is the inertia torque, and D is the unwinding diameter. When the rotation of the unwinding roll changes from the acceleration state to the constant velocity state, τ _AC becomes zero. As a result, the balance is lost and the tension drops to T'in the following equation. T ′ · D / 2 = τ _B ′ (2) Then, the brake torque τ _B ′ changes to τ _B so that the target tension T is obtained by the operation of the controller 6, and the tension returns to the original value.

When changing from the constant speed to the deceleration, the following occurs. When the tension is balanced at a constant speed, the following equation holds. T · D / 2 = τ _B (3) At deceleration, inertia torque τ _AC is generated due to the deceleration of the unwinding roll 2 and acts to reduce the brake torque τ _B , and the tension drops to T ′. T ′ · D / 2 = τ _B −τ _AC (4) Then, the brake torque is τ due to the operation of the controller 6.
It changes from _B to τ _B ″, and the tension becomes the original value.

[0009]

As described above, the correction of the tension fluctuation due to the inertia torque is performed in the closed loop control as shown in FIGS. 8 and 9. For this reason, the fluctuation of the tension is corrected after the fluctuation occurs, so that the response is delayed. Conventionally, the acceleration / deceleration time of a machine to which such a control device is attached is relatively long, and the unwinding roll is not so large, so the inertia torque itself is small,
The tension fluctuation was also small, so there was not much trouble.

However, with the recent increase in speed and size of the apparatus, the torque related to acceleration and roll diameter has increased. Therefore, the tension fluctuation becomes large, and the time from the tension fluctuation state at the end of acceleration or the start of deceleration to the original set tension becomes long.

FIG. 10 is a diagram showing changes in the unwinding speed and tension of the web with the passage of time. (A) shows the speed of the web, which is in the accelerating state from the start to time t1, t1
A constant speed state is shown until t2, and a deceleration state is shown from t2 to the end. (B) shows the tension of the web, and shows a state in which the tension decreases for a while after the time t1 when the acceleration ends and the time t2 when the deceleration starts, and is corrected by the action of the controller 6 to return to the original state.

When the time required for the tension to change and to return to the original state becomes long as described above, various problems such as the meandering of the web and the breakage of paper have come to occur. Therefore, there is a method of increasing the responsiveness of the controller 6 (generally increasing the gain of the controller 6), but this method deteriorates the stability of tension control at a constant speed. In particular, the stability is poor when the winding diameter becomes small.

FIG. 11 is a diagram showing a method of increasing the gain when the tension changes. This method is a method in which the gain element 10 is provided on the downstream side of the control output, the gain is switched to a large value at times t1 and t2 shown in FIG. 10, and the gain is returned to the original value after a lapse of a certain time. In this method, since the proportional gain is switched, a disturbance is generated when the gain is returned to the original gain. Complex control is required to restore the original gain to bumpless.

In order to prevent the tension from decreasing at the end of acceleration,
There is a method of applying an output bias of a magnitude corresponding to the inertia torque τ _AC at the end of acceleration. However, in this method, since the biased state is maintained, the bias remains in the control in the steady state, the unwinding diameter of the unwinding roll becomes small, and when the control output becomes small, this bias becomes relatively small. It becomes a large value and control becomes difficult.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a tension control device that reduces fluctuations in web tension at the end of acceleration and the start of deceleration.

[0016]

In order to achieve the above object, in a tension control device for performing feedback control of the tension of a strip unrolled from a roll so as to reduce the deviation between its measured value and a target value, at the end of acceleration and At the start of deceleration, the target value is increased by a predetermined amount for a predetermined period.

Further, in a tension control device for feedback-controlling the tension of the strip unrolled from the roll so as to reduce the deviation between the measured value and the target value, the control output indicates the inertia of the roll from the start to the end of acceleration. A negative bias corresponding to the torque is applied, and a positive bias corresponding to the inertia torque is applied from the start of deceleration to the stop.

Further, in the tension control device for feedback controlling the tension of the strip unrolled from the roll so as to reduce the deviation between the measured value and the target value, the gain of the feedback control is set at the end of acceleration and the start of deceleration. Increase by a predetermined amount for a predetermined period.

Further, the predetermined amount or the bias amount is changed according to the rotational acceleration and the diameter of the roll.

[0020]

[Function] Since the tension of the strip decreases as shown in FIG. 10 (b) during a certain time from the end of acceleration and the start of deceleration, only the amount corresponding to this decrease amount is previously set during this time. By increasing the target value, it is possible to prevent the tension of the strip from decreasing.

From the start to the end of acceleration (1)
A negative bias corresponding to this period tau _AC added since the _AC tau as shown in Equation applied, since to the stop than the start of deceleration (4) _AC tau as shown in the expression applied to the negative direction, this time tau _AC
By applying a positive bias corresponding to, it is possible to prevent the tension variation of the strip.

Further, by increasing the gain of the feedback control by a predetermined amount from the end of acceleration and from the start of deceleration by a predetermined amount, the tension of the belt-shaped body is reduced, but the time to return to the original is shortened. The probability of occurrence can be reduced.

Further, since the inertia torque τ _AC and the unwinding diameter D shown in the equations (1) and (4) change depending on the rotational acceleration of the unwinding roll and the change in the unwinding diameter, the control according to these changes. By performing the above, control is achieved so that the target tension is maintained for a long time.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the first embodiment of the present invention. The apparatus of this example and the examples described below are the same as the apparatus described in FIG. Further, blocks having the same reference numerals as the constituent blocks of the controller 6 shown in FIG. 9 have the same functions.

In FIG. 1, reference numeral 61 is an amplifier for amplifying the detected tension from the tension detector 5, 62 is a tension setter for setting the target tension of the web 1, 63 is a deviation circuit for obtaining the deviation between the target tension and the detected tension, 64 Outputs a control output to the brake 3 by an arithmetic circuit that performs PI control arithmetic on this deviation. 64 is not limited to a proportional / integral operation (PI operation), but may be a PID operation with a derivative operation, or a P operation or an I operation.

Reference numeral 65 is a correction setting circuit for correcting the target tension set by the tension setter 62. In this embodiment, as shown in FIG. 10B, a value for correcting the decrease in tension is set for a predetermined period after t1 and t2.

An adder 66 outputs a corrected target tension obtained by adding the correction value of the correction setting circuit 65 and the target tension. The switch 67 switches between the target tension and the corrected target tension. 68 is a timing circuit that determines the timing of the end of acceleration and the start of deceleration of the unwind roll 2. The end point of acceleration can be obtained by detecting that the speed of the web 1 has reached a predetermined speed, and the start of deceleration can be obtained from the deceleration command signal. When the timing circuit 68 notifies the timing circuit 68 of the end point of acceleration and the start point of deceleration, the switch 67 switches the switch 67 for a predetermined time.
To output the corrected target tension, and returns it to the tension setter 62 side after a lapse of a predetermined time.

FIG. 2 is a diagram showing the operation of the first embodiment.
(A) shows the unwinding speed of the web 1, where t1 is the acceleration state, t1 to t2 is the constant speed state, and t2 is the deceleration state from the stop to the stop. (B) shows the target tension and the corrected target tension, and the corrected target tension is output from t1, t2 to tm. (C) shows the output of the tension detector 5 by the tension of the web 1. The tension has a constant value without decreasing even in the vicinity of t1 and t2.

Next, the operation of this embodiment will be described. The target tension from the tension setter 62 is input to the deviation circuit 63 during a period excluding tm from the end of acceleration and tm from the start of deceleration. At the end of acceleration from the timing circuit 68 or at the timing of deceleration start, the timer circuit 69 is started,
While this timer is operating, the correction target tension is
Entered in 63.

If the correction value of the correction target tension is properly selected, the tension of the web 1 maintains a constant value as shown in FIG. 2 (c). It should be noted that the timing signals for the end of acceleration and the start of deceleration may be output slightly earlier than the end of acceleration and the start of deceleration, in consideration of the delay of the arithmetic circuit 64. When the acceleration is to be performed earlier than the end of the acceleration, the acceleration should be performed at a speed slightly lower than the target speed of the web 1, and at the time of deceleration, it may be output slightly before the deceleration signal is output.

Although the above correction operation has been described as being executed by the controller 6 composed of hardware, it may be executed by the controller centering on the processing by software.

FIG. 3 is a block diagram showing an example of the correction setting circuit 65 shown in FIG. The above explanation is the unwinding roll 2.
Although the unwinding diameter was constant, the unwinding diameter of the web 1 naturally decreased. Also, the acceleration of unwinding the web 1 may change. Therefore, the correction value of the correction setting circuit 65 needs to be corrected in accordance with these changes.

Τ _{AC in} equations (1) and (4) is expressed as follows. τ _AC = Idω / dt = πρ · D ³ α / 16 (5) Since the relationship between the tension T and the torque τ is expressed by the equation (2), T _{AC of the} tension correction value is T _AC = 2τ _AC / D = πρD ² α / 8 (6) I: Second moment of inertia of unwinding roll ω: Rotating angular velocity of unwinding roll ρ: Mass per unit cross-sectional area of unwinding roll (kg /
m ² ) D: Diameter of the web wound on the unwinding roll α: Traveling acceleration of the web

In FIG. 3, a differentiation circuit 661 differentiates the traveling speed signal of the web to calculate α. A multiplier 662 inputs the diameter signal D and calculates D ² . 663 is also a multiplier α,
D ² and a constant πρ / 8 are input, and T _AC shown in equation (6) is output as a correction signal. With this correction signal, the correction setting tension corresponding to the change in the running acceleration of the web and the unwinding diameter of the web can be input to the deviation circuit 63.

The running speed of the web is obtained from the operating speed of the device, and the diameter signal is obtained by touching the surface of the unwinding roll to check the amount of movement due to the change in diameter, or the rotational speed of the unwinding roll and the rotational speed of the measuring roll. It can be obtained because it is a method of matching and.

Next, a second embodiment will be described with reference to FIGS. FIG. 4 is a block diagram showing the configuration of the second embodiment,
70 is a timing circuit that detects the end of acceleration and the start of deceleration, and 71 is a correction setting circuit that generates a bias amount corresponding to τ _AC in equations (1) and (4), and from the start to the end of acceleration. It outputs a negative bias amount, and outputs a positive bias amount from the start of deceleration to the stop. A switch 72 outputs a bias from the correction setting circuit 71 during the acceleration period and the deceleration period according to an instruction from the timing circuit 70. 73 is an adder and is an arithmetic circuit
The output of 64 and the output from switch 72 are added.

FIG. 5 is a diagram for explaining the operation of this embodiment. (A) is the same as (a) of FIG. (B) is the brake torque τ _B of equations (1) and (4).
(C) is a calculation output of the calculation circuit 64. (D) shows the bias output from the correction setting circuit 71.

Next, the operation of this embodiment will be described. The inertia torque τ _AC at the end of acceleration or at the start of deceleration is offset by adding and subtracting a bias amount to the output of the controller 6, and the tension of the web 1 is prevented from decreasing at t1 and t2.

During acceleration, the amount of bias corresponding to the inertia torque τ _AC is reduced. By doing so, the arithmetic circuit 64 outputs a control output that generates the required torque including this bias amount. If this bias amount is set to zero at the end of acceleration, the output will increase correspondingly, and it will act as a correction operation. Further, during deceleration, a bias amount having a magnitude corresponding to the inertia torque is added from the start of deceleration to correct the required torque due to deceleration. The output of the correction setting circuit 71 may be calculated by calculating τ _AC in the equation (5) and output.

In FIG. 5 (c), the calculation output is shown as constant during acceleration / deceleration, but for simplicity of explanation, it is assumed that the unwinding diameter D of the unwinding roll 2 during acceleration / deceleration does not change. It depends on what you did. However, since the diameter D changes in actual operation, the calculation output also changes corresponding to this change.

Next, a third embodiment will be described with reference to FIGS. 6 and 7. FIG. 6 is a block diagram showing the configuration of this embodiment.
In this embodiment, the tension variation period at the times t1 and t2 is shortened by making the integration time of the PI operation arithmetic circuit 64 variable. The timing circuit 642 outputs t1 at the end of acceleration and t2 at the start of deceleration, and the timer circuit operates the switch 644 for a predetermined time from t1 and t2 to connect the resistors R1 and R2 in parallel so that a large amount of current flows through the capacitor C. To 641 is an operational amplifier. In the above example, the integral gain is increased by shortening the integration time of the PI operation, but the proportional gain may be increased.

FIG. 7 is a diagram showing the operation of this embodiment.
10 (a) is the same as FIG. 10 (a), and FIG. 10 (b) shows the tension of the web 1 of this embodiment by a solid line, and the portion shown by a dotted line is FIG.
Is the same as (b). (C) shows the operation output of the operation circuit 64, the solid line part shows the present embodiment, and the dotted line part shows the output of the operation circuit 64 described in FIG.

Next, the operation will be described. Timer circuit 64
The switch 644 that performs a switching operation according to the output of 3 is normally on the b side, and the capacitor C has a current (i
1 = e / R1: E is a voltage between a and d), charging is performed and the calculation result is output. When the switch is operated to side a at the end of acceleration or at the start of deceleration, i2 =
The current of e / R2 newly flows, and the capacitor C is charged by the current of i1 + i2. As a result, the calculation output is R1.
Change faster than when That is, the response becomes faster.
Time required for correction After setting the switch 644 to the a side and then returning to the b side, the original response is restored. As a result, the response is accelerated as shown in FIG. 7C, and the decrease in tension and the decrease time are reduced as shown in FIG. 7B.

[0044]

As is apparent from the above description, according to the present invention, the target tension is converted at the end of acceleration and the start of deceleration of the unwinding roll, the integration time is shortened, and a negative bias is applied during acceleration. By adding a positive bias during deceleration, fluctuations in web tension at the end of acceleration and at the start of deceleration are reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a diagram showing an operation of the first embodiment.

FIG. 3 is a diagram illustrating an example of a correction setting circuit.

FIG. 4 is a block diagram showing a configuration of a second embodiment.

FIG. 5 is a diagram showing an operation of the second embodiment.

FIG. 6 is a block diagram showing a configuration of a third exemplary embodiment.

FIG. 7 is a diagram showing an operation of the third embodiment.

FIG. 8 is a diagram showing a configuration of an unwinding roll device.

FIG. 9 is a block diagram showing a configuration of a conventional controller.

FIG. 10 is a diagram showing an operation of the unwinding roll device by the conventional controller.

FIG. 11 is a diagram showing an improved example of a conventional controller.

[Explanation of symbols]

1 web 2 Unrolling roll 3 brakes 4 guide rolls 5 Tension detector 6 controller 62 Tension setter 63 Deviation circuit 64 arithmetic circuit 65,71 Correction setting circuit 67,72,644 switch 68,70,642 Timing circuit 69,643 Timer circuit

Claims (4)

[Claims] 1. A tension control device for feedback controlling tension of a strip unrolled from a roll so as to reduce a deviation between a measured value and a target value, the target value being a predetermined amount for a predetermined period at the end of acceleration and the start of deceleration. A tension control device characterized by increasing the number. 2. A tension control device for feedback controlling tension of a strip unrolled from a roll so as to reduce a deviation between a measured value and a target value, wherein a control output indicates inertia of the roller from start to end of acceleration. A tension control device, wherein a negative bias corresponding to torque is applied, and a positive bias corresponding to the inertia torque is applied from deceleration start to stop. 3. A tension control device for feedback-controlling the tension of a strip unrolled from a roll so as to reduce the deviation between a measured value and a target value, wherein the gain of the feedback control is set to a predetermined value at the end of acceleration and at the start of deceleration. A tension control device characterized by increasing a predetermined amount for a period. 4. The tension control device according to claim 1, wherein the predetermined amount or the bias amount is changed according to a change in rotational acceleration and a diameter of the roller.