JP2012090455A - Method and apparatus of controlling roller speed for paper machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize impact of paper breakage on an entire paper machine system by suppressing influence of disturbance on upstream when paper breakage occurs between rollers in the paper machine system.SOLUTION: When tension fluctuation occurs at a real tension fluctuation assumption point between a conveyance roller 4R and a conveyance roller SR, the conveyance roller 4R in a pre-stage needs a torque reference additional output equal to sheet tension coming from the roller SR in a subsequent stage. The sheet tension detected by a tension detection device TD is deducted from an output of a speed controller 13 when the tension fluctuation does not occur at the real tension fluctuation assumption point, so that a torque controller 17 is immediately corrected when the tension fluctuation occurs at the real tension fluctuation assumption point, to impart a torque reference equal to the sheet tension necessary for the conveyance roller 4R to the torque controller 17. Consequently, speed variation can be suppressed at upstream of a real tension fluctuation occurrence point.

Description

  The present invention relates to a roll speed control method and apparatus for a paper machine which suppresses a transient speed fluctuation of the roll accompanying an actual tension fluctuation in a paper machine system and eliminates an upstream effect.

  In the paper machine, in order to transport the paper (sheet material) to be manufactured, the roll driving torque includes the paper transport torque, the mechanical loss torque of the transport roll, and the tension component torque for maintaining the tension between the rolls. Is required.

  When actual tension fluctuations occur during the production of paper by a paper machine, the paper transport torque by the subsequent roll of the part where the actual tension fluctuations occur decreases. For this reason, the torque of the front roll is relatively insufficient, and the speed of the front roll at the actual tension fluctuation portion is reduced. As a result, a slack of paper is generated in the upstream portion of the preceding roll, and a broken chain is generated, for example, the loose paper is broken in the upstream portion due to being caught in the previous roll.

  In this way, in the paper machine system, once a paper break occurs and the broken part expands, in order to avoid a decrease in operation efficiency due to re-passage, even if an actual tension fluctuation occurs, the upstream side It is desired to perform control without affecting the part.

Masahiro Miura “Current Status of Drive Systems for Paper Manufacturing Equipment” Paper Journal, Vol. 64, No. 3, March 2010

  As described above, in the conventional apparatus, when the actual tension fluctuation occurs, the torque corresponding to the tension generated by the subsequent roll of the actual tension fluctuation occurrence point rapidly decreases, and as a result, the speed fluctuation occurs in the upstream roll. Occurs, the sheet material sags, etc., and further leads to fluctuations in actual tension upstream.

  Therefore, as described in Non-Patent Document 1, a system for adding a torque correction signal corresponding to the tension fluctuation is considered, assuming that an actual tension fluctuation occurs between the rolls when the paper break detecting means detects the paper break. It is done. However, this system not only requires a paper break detection means, but also has a problem that a control response is delayed and sufficient control cannot be performed because it must respond instantaneously at the time of paper break detection.

  The present invention has been made in view of the above circumstances, and by calculating and correcting the torque corresponding to the tension between the rolls using the existing tension detection means, the actual tension can be obtained without adding a new sheet breakage detection means. It is an object of the present invention to provide a roll speed control method and apparatus for a paper machine having a function of suppressing transient speed fluctuations that can suppress the influence on other sections that occur during fluctuations.

  In order to achieve the above object, the roll speed control method of the paper machine according to the present invention detects the tension between the rolls of the sheet material flowing between the drive roll and the latter stage roll to be controlled by the tension detection means. The torque calculating means calculates a torque corresponding to the tension between the subsequent rolls of the drive motor shaft based on the detected tension between the rolls, the radius of the drive roll, and the gear ratio between the drive roll and the drive motor. Further, the calculated tension component torque signal is always subtracted from the speed control signal for the drive roll as a tension component torque correction value for the subsequent roll, thereby suppressing the transient speed fluctuation of the drive roll.

  A roll speed control device for a paper machine according to the present invention includes a tension detection means for detecting a tension between rolls of a sheet material that flows between a drive roll and a subsequent roll that are speed control targets, and rotates the drive roll. Drive control means for driving and controlling the drive motor, speed control means for generating a speed control signal based on a speed reference signal for the drive motor, tension between rolls detected by the tension detection means, and radius of the drive roll A torque calculating means for calculating a torque corresponding to the tension between the subsequent rolls of the drive motor shaft based on a gear ratio between the drive roll and the drive motor, and a torque correction for the tension by the subsequent rolls of the calculated tension torque signal. Speed that suppresses transient speed fluctuation of the drive roll by constantly subtracting as a value from the speed control signal output from the speed control means It is characterized by comprising a control means.

  In addition, the speed suppressing means always generates a polarity reversing means for reversing the polarity of the calculated torque signal for the tension, and the generated reversing signal is always used as a speed control signal output from the speed control means. It is characterized by comprising addition means for adding.

  According to the present invention, when the actual tension fluctuation occurs between the rolls, the tension torque applied to the sheet by the subsequent roll is lost, but the tension torque correction value subtracted from the speed control signal is always The amount of torque lost by the tension of the subsequent roll can be applied to the roll, and the output of the speed control device can be controlled while being constant, so that fluctuations in the speed of the roll can be suppressed.

  Therefore, the torque required for the preceding roll when the actual tension fluctuates can be applied to the roll without causing a steep fluctuation. Further, by continuing to add the correction value before occurrence of the actual tension fluctuation, it is possible to suppress the speed fluctuation that occurs during the actual tension fluctuation without using an independent sheet breakage detection device. Variations in the tension of the sheet material occurring between the rolls can be avoided.

It is a block diagram which shows the structure of one Embodiment of the apparatus which concerns on this invention. It is explanatory drawing which shows the effect | action of embodiment shown in FIG. It is explanatory drawing which shows the effect | action of the conventional control which does not carry out tension compensation. It is explanatory drawing which shows the effect | action of the conventional control described in the nonpatent literature 1.

  Hereinafter, an embodiment of a roll speed control device for a paper machine, which is characterized by suppressing transient speed fluctuations according to the present invention, will be described with reference to FIG.

  As shown in FIG. 1, in this embodiment, paper (hereinafter also referred to as “sheet material”) 1 that has passed through a roll 3R of a 3D stand is a roll 4R of a 4D stand that constitutes a pre-dryer part, and a size press part. It is assumed that the roll is transported through the roll SR of the SZ stand that constitutes and the transport roll 5R of the 5D stand that constitutes the dry part, and the roll speed of the transport roll 4R of the 4D stand will be described as an object of speed control.

  The roll speed control device 11 in the present embodiment controls the speed of the electric motor M that drives the transport roll 4R of the 4D stand, and includes a speed controller 13, an adder 15, a torque controller 17, and tension / torque. A converter 19 and a polarity inverter 21 are provided. In the figure, TD denotes a tension detector that detects the tension of the sheet material 1 passing between the transport roll 4R of the 4D stand and the transport roll SR of the size press part SZ, and the detection signal T2fbk is While being output to the tension / torque converter 19, it is supplied to a control unit (not shown) for tension correction control of the latter-stage roll that is generally performed. RV is a speed detector that detects the speed of the motor M.

  The speed controller 13 receives the motor angular speed reference signal ωref and the motor angular speed feedback signal ωfbk fed back from the speed detector RV of the motor M, and generates a speed control signal ASRout that makes the deviation zero.

  The adder 15 generates a torque reference signal τref obtained by adding the tension torque compensation signal τc (ten) from the speed control signal ASRout.

  The torque controller 17 includes a vector control unit 23 that receives the torque reference signal τref and executes vector calculation, and an inverter circuit unit 25 that generates a speed controller output signal and controls the motor M. .

  The tension / torque converter 19 receives the tension detection signal T2fbk detected by the tension detector TD, and generates a motor shaft equivalent tension torque signal τmot (ten).

  The polarity inverter 21 generates a tension torque compensation signal τc (ten) obtained by inverting the polarity of the input motor shaft converted tension torque signal τmot (ten) and outputs the tension torque compensation signal τc (ten) to the adder 15.

  In the above configuration, the sheet material 1 is conveyed rightward in the drawing by the conveyance roll 4R and the subsequent conveyance roll SR. The transport roll 4 </ b> R is driven by an electric motor M, and the electric motor M is torque / speed controlled by a torque controller 17. The tension detector TD detects the sheet tension value of the sheet material 1 between the transport roll 4R and the transport roll SR. The tension / torque converter 19 calculates a torque for the tension (motor shaft equivalent tension signal) from the mechanical constants such as the diameter and gear ratio of the transport roll SR and the sheet tension value detected by the tension detector TD. ing. The polarity inverter 21 reverses the polarity of the torque corresponding to the tension and adds it to the output of the speed controller 13.

  The assumed part of actual tension fluctuation assumed in the present invention is actual tension fluctuation occurring between the transport roll 4R and the transport roll SR. When actual tension fluctuation occurs at the actual tension fluctuation assumed position, the transport roll 4R does not receive the torque corresponding to the sheet tension generated by the transport roll SR, and the torque received from the transport roll SR downstream of the transport roll 4R is insufficient. As a result, speed fluctuation occurs.

  In a state where the sheet material 1 is normally conveyed, a torque value corresponding to the sheet tension detected by the tension detector TD is calculated by the tension / torque converter 19 and inverted by the polarity inverter 21, and this inverted signal is the torque. It is added to the torque command value input to the torque controller 17 as a correction value (tension torque compensation signal τc (ten)). In the steady state, the torque for the tension required for the transport roll 4R is generated by the transport roll SR. Therefore, the speed controller 13 matches the torque for the tension generated by the transport roll SR in addition to the transport torque of the transport roll 4R. However, in this embodiment, the output of the polarity inverter 21 is added by the adder 15 in order to suppress excessive speed fluctuations, and the torque controller 17 includes the transport roll 4R. Only the conveyance torque of is input.

  In this state, when an actual tension fluctuation occurs near the actual tension fluctuation assumed portion between the transport roll 4R and the transport roll SR, and the tension between the rolls decreases, the tension detected by the tension detector TD decreases, The output of the tension / torque converter 19 decreases. As a result, the torque correction value (tension-related torque compensation signal τc (ten)) decreases, and the total value of the conveyance torque and the tension-related torque calculated in advance is given to the torque controller 17, and the conveyance roll 4R. It is possible to instantaneously follow up to an appropriate value of the torque value required. Thereby, the conveyance roll 4R can continue an operation | movement, without generating a speed fluctuation | variation, and can suppress the chain of the fracture | rupture to an upstream section.

  The motor shaft equivalent tension component torque signal τmot (Ten) [N · m] generated by the tension / torque converter 19 can be obtained by the following equation (1).

τmot (Ten) = r · G · Ten2 (1)
However, r: roll radius, G: reduction ratio, Ten2: tension between the transport roll 4R and the transport roll SR As described above, according to the embodiment of the present invention, the existing tension detector TD is used. This makes it possible to suppress speed fluctuations due to actual tension fluctuations without adding a new detection device to the paper machine line.

<Verification of effect of embodiment>
Next, the effect of this embodiment is demonstrated, comparing with a prior art.

  FIG. 2 is a characteristic diagram for verifying the operational effect when the tension component torque according to the embodiment of the present invention is always corrected, FIG. 3 is a characteristic diagram when the tension component torque is not corrected, and FIG. It is a characteristic view in the case of instantaneously correcting the minute torque. In each figure, (a) is a characteristic diagram showing the tension with respect to time, (b) is a characteristic diagram showing the load torque (torque at the roll shaft) of the 4D stand (conveying roll 4R) with respect to time, and (c) is 4D with respect to time. FIG. 4 is a characteristic diagram showing the motor output torque of the stand, (d) is a characteristic diagram showing torque correction for the tension of the 4D stand, and (e) is a characteristic diagram showing the motor angular velocity of the 4D stand.

  As shown in (a) of each figure, it is assumed that the paper exits the 4D stand from the 3D stand (conveying roll 3R) and flows to the 5D stand (conveying roll 5R), and the time t2 immediately before entering the 5D stand. Assume that a paper break occurred at that time. In (a), Ten1 indicates the tension between the 3D stand and the 4D stand, and Ten2 indicates the tension between the 4D stand and the SD stand.

As shown in (b), the load torque of the 4D stand during the passage of paper sequentially between the 3D stand and the 4D stand is the output torque τ (Mech) caused by the mechanical loss of the motor and the pulling from the upstream side. Output torque signal (motor shaft equivalent tension torque signal) τ (Ten1) caused by the tension Ten1 applied, and output torque signal (motor shaft equivalent tension torque signal) τ (Ten2) caused by the tension Ten2 pulled from the downstream side. Is the total value. That is, the motor output torque τmot of the 4D stand is
τmot = τmot (Ten1) + τmot (Mech) −τmot (Ten2) (2)
It becomes.

  Accordingly, the actual motor output torque τmot is a curve as shown by a thick broken line in FIG.

  In the embodiment of the present invention, as shown in FIG. 2 (d), the torque correction amount (the motor shaft equivalent tension) corresponding to the tension detected in advance on the exit side of the transport roll 4R of the 4D stand before the occurrence of the paper break. The signal τc (ten) obtained by inverting the minute torque signal τmot (ten) is added.

  In other words, when a negative polarity correction signal equivalent to the tension torque τ (Ten2) is always given to the speed controller output, the loss of τ (Ten2) due to a paper break compensates the torque reference as feedforward control, and speed control The instrument output does not have to change. Alternatively, it is only necessary to control the difference after the torque compensation for the tension.

  Further, as shown in FIG. 2 (e), the angular velocity slightly decreases when a paper break occurs. In addition, the curve shown with a dashed-two dotted line is a case where there is no correction | amendment, and it turns out that it has fallen largely. In this embodiment, a slight depression is sufficient. This is because the change in the tension component torque τ (ten2) compensates for the torque reference as a constant feed-forward control, so that the speed variation can be kept low even if the tension component torque changes suddenly. Therefore, as shown in FIG. 2 (d), when a paper break occurs, although there is a slight delay in the torque detection signal corresponding to the tension, the actual load torque and the motor output torque are It can be understood that the difference is small and is surely compensated.

<When the torque for tension is not corrected>
As shown in FIG. 3E, when the torque corresponding to the tension is not corrected at all, the motor angular speed of the 4D stand is greatly reduced when the paper break occurs. This is because the speed reduction amount and the recovery response time are determined by the load response characteristics of the speed control system. It can be seen that the difference between the actual load torque and the motor output torque is large due to the decrease in speed, as indicated by the diagonal lines in FIG. Therefore, in the case of no correction, there is a problem that the adjacent upstream side paper is loosened and the paper breakage spreads.

<When tension torque is corrected when a paper break occurs (instant correction described in Non-Patent Document 1)>
As shown in FIG. 4C, when the tension torque is corrected when a paper break occurs, a correction delay time td from when the paper break is detected until the tension is actually corrected occurs. Therefore, the actual motor output torque is also delayed by this delay time td. Further, as indicated by the hatched lines in the figure, the difference between the actual load torque and the motor output torque is larger than that in the case of the present embodiment. The delay time td is about 2 seconds, and there is a problem in that it is erroneously determined that a paper break has occurred although no paper break has occurred. In the present embodiment, since the torque corresponding to the tension is always corrected, the delay time can be shortened as much as possible, thereby preventing erroneous determination of the occurrence of a sheet break.

DESCRIPTION OF SYMBOLS 1 Sheet | seat material 3R, 4R, SR, 5R Conveyance roll 11 Roll speed control apparatus 13 Speed controller 15 Adder 17 Torque controller 19 Tension / torque converter (torque calculating means)
21 Polarity reverser (speed control means)
23 Vector control unit 25 Inverter control unit TD Tension detector RV Speed detector 17 Adder (speed suppression means)

Claims (3)

The tension between the rolls of the sheet material flowing between the drive roll and the subsequent roll that is the target of speed control is detected by the tension detection means,
The torque calculation means calculates the torque corresponding to the tension between the subsequent rolls of the drive motor shaft based on the detected tension between the rolls, the radius of the drive roll, and the gear ratio between the drive roll and the drive motor,
Suppressing the transient speed fluctuation of the driving roll by constantly subtracting the calculated tension torque signal from the speed control signal for the driving roll as a tension torque correction value for the subsequent roll.
A roll speed control method for a paper machine. Tension detecting means for detecting the tension between the rolls of the sheet material flowing between the drive roll and the subsequent-stage roll that are targets of speed control;
Drive control means for driving and controlling a drive motor for rotating the drive roll;
Speed control means for generating a speed control signal based on a speed reference signal for the drive motor;
Torque calculation for calculating the torque corresponding to the tension between the subsequent rolls of the drive motor shaft based on the tension between the rolls detected by the tension detection means, the radius of the drive roll, and the gear ratio between the drive roll and the drive motor. Means,
Speed suppression means for suppressing the transient speed fluctuation of the drive roll by constantly subtracting the calculated tension torque signal from the speed control signal output from the speed control means as a tension torque correction value for the subsequent roll;
A roll speed control device for a paper machine, comprising: In the roll speed control device of the paper machine according to claim 2,
The speed suppression means always adds a polarity inversion means for generating an inverted signal obtained by inverting the polarity of the calculated torque signal for the tension, and adds the generated inversion signal to the speed control signal output from the speed control means. A roll speed control device for a paper machine, characterized by comprising an adding means.

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