EP1091032A2 - Ablass-Steuervorrichtung für Webmaschinen - Google Patents

Ablass-Steuervorrichtung für Webmaschinen Download PDF

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Publication number
EP1091032A2
EP1091032A2 EP00120680A EP00120680A EP1091032A2 EP 1091032 A2 EP1091032 A2 EP 1091032A2 EP 00120680 A EP00120680 A EP 00120680A EP 00120680 A EP00120680 A EP 00120680A EP 1091032 A2 EP1091032 A2 EP 1091032A2
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EP
European Patent Office
Prior art keywords
tension
controller
calculator
weaving machine
control device
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP00120680A
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English (en)
French (fr)
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EP1091032A3 (de
Inventor
Tsutomu Tsudakoma Kogyo Kabushiki Kaisha Sainen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Tsudakoma Corp
Original Assignee
Tsudakoma Industrial Co Ltd
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Filing date
Publication date
Application filed by Tsudakoma Industrial Co Ltd filed Critical Tsudakoma Industrial Co Ltd
Publication of EP1091032A2 publication Critical patent/EP1091032A2/de
Publication of EP1091032A3 publication Critical patent/EP1091032A3/de
Withdrawn legal-status Critical Current

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    • D—TEXTILES; PAPER
    • D03—WEAVING
    • D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
    • D03D49/00—Details or constructional features not specially adapted for looms of a particular type
    • D03D49/04—Control of the tension in warp or cloth
    • D03D49/06—Warp let-off mechanisms

Definitions

  • This invention relates to a let-off control device for a weaving machine capable of achieving desirable controllability in a stable fashion regardless of variations in rotational speed of the weaving machine.
  • a let-off control device of a weaving machine controls a warp beam via a let-off motor in such a way that a specific warp tension is maintained.
  • a conventionally known problem of the let-off control device is that if a simple feedback control system is configured and a large integration time constant is inserted in a warp tension detecting system, overall response significantly deteriorates, making it difficult to achieve a specific degree of controllability. This is because the warp tension considerably fluctuates during each rotation of a main shaft of the weaving machine due to a various operations of the weaving machine such as a warp shedding motion during which a peak warp tension could rise up to as much as twice of the average warp tension.
  • Japanese Unexamined Patent Publication No. 59-157354 proposes a let-off control device of a weaving machine to overcome the aforementioned problem.
  • This let-off control device calculates a basic speed of a let-off motor based on the rotational speed of the weaving machine and warp winding diameter on its warp beam, detects warp tension at a specific angle of rotation (hereinafter referred to as the crank angle) of a main shaft during its each successive turn, calculates the amount of speed correction for the let-off motor based on an moving average of the warp tension, and controls the speed of the let-off motor based on the basic speed corrected by the calculated amount of speed correction.
  • the crank angle a specific angle of rotation
  • a controller for calculating the amount of speed correction has control elements for performing proportional, integral and differential (control) actions and calculates the amount of speed correction each time the moving average of the warp tension is calculated. Therefore, it is not necessary to insert a large integration time constant in a warp tension detecting system and it is possible to achieve desirable controllability by using correction control by a feedback control system based on the moving average of the warp tension in addition to a feed-forward control system based on the basic speed.
  • a time delay (a lag element; a time delay), i.e., from the time detecting a warp tension to the time the corrected speed is output, can be maintained at substantially a constant value.
  • a time delay i.e., from the time detecting a warp tension to the time the corrected speed is output
  • the aforementioned let-off control device employing said PID controller readjustment of a control gain, in particular a proportional gain, for the PID controller is necessitated.
  • the proportional gain (gain value) having suitably adjusted for a low speed weaving operation
  • the adjusted time delay factor would be too long for the high speed operation.
  • the proportional gain set for the low speed weaving operation will be too large for the proportional gain needed for the effective control in the high speed weaving operation.
  • the control gain i.e., not only a proportional gain but also an integral gain and a differential gain, is changed in accordance with the speed of the weaving operation, the effective control of the weaving operation cannot be performed.
  • the controller calculating the amount of speed correction calculates the amount of speed correction each time the moving average of the warp tension is calculated, that is, the amount of speed correction is calculated every rotation of the main shaft of the weaving machine.
  • the prior art technology has a problem that it is difficult to maintain desirable controllability. Because when the rotational speed of the weaving machine changes due to the particular weaving operation, leading to the change in sampling time (frequency), what was previously optimum control gain adjusted prior to the change in rotational speed is no longer the optimum gain for the weaving operation after the change in rotational speed. It is, thus, highly likely that those previously adjusted gain values (for the control gain) are in excess or in lack with respect to the optimum values for the new weaving operation at new rotational speed. Accordingly, with the aforementioned prior art technology, unless the control gain is readjusted at the time of change in rotational speed of the weaving machine, it becomes difficult to maintain the desirable controllability.
  • a second object of the invention is to provide a let-off control device for a weaving machine which can automatically set optimum control parameters for a controller for calculating the amount of speed correction with an additional provision of an automatic tuning circuit, and thereby achieve desirable controllability with ease.
  • a let-off control device of the invention for a weaving machine comprises a basic speed calculator for calculating a basic speed of a let-off motor, an average tension calculator for calculating a moving average of warp tension detected at a specific crank angle in one or more picks, a controller for calculating a speed correction value for the let-off motor based on deviation of average tension fed from the average tension calculator with respect to a target tension, and a control amplifier for controlling the speed of the let-off motor based on the basic speed fed from the basic speed calculator and the speed correction value fed from the controller, wherein the controller operates in synchronism with an operating cycle which is independent from an operating cycle of the average tension calculator.
  • the average tension calculator obtains the average tension by calculating the moving average of the warp tension at the specific crank angle during multiple picks. Specifically, the average tension calculator detects the warp tension at the specific crank angle in each successive rotation of a main shaft of the weaving machine and determines the average tension by calculating the moving average of the warp tension thus detected during the most recent rotations of the main shaft. Accordingly, the operating cycle of the average tension calculator is completely synchronized with the rotations of the main shaft.
  • the controller since the controller operates in synchronism with the operating cycle which is independent from the operating cycle of the average tension calculator, there is no likelihood that sampling time varies and thereby substantial control parameter loses its optimum state even when the rotational speed of the weaving machine changes.
  • the controller operates according to a clock signal independent of the rotational speed of the weaving machine and may include control elements for performing proportional, integral and differential (control) actions, or those for performing proportional and integral (control) actions only.
  • the controller operates in synchronism with the operating cycle which is shorter than the operating cycle of the average tension calculator.
  • the let-off control device may further comprise a correction calculator for adjusting the speed correction value fed from the controller based on the winding diameter of warp on a let-off beam.
  • the speed correction value fed from the controller is adjusted by the correction calculator based on the winding diameter of warp on the let-off beam, it becomes possible to achieve good controllability. This is because, although a transfer function of a mechanical system from the let-off motor to the warp tension varies when the winding diameter of the warp on the let-off beam decreases due to the consumption of the warp for instance, the correction calculator can properly compensate for such variations.
  • the let-off control device may further comprise a switching circuit which disables the controller when a tuning command is issues, and an automatic tuning circuit which updates a control parameter of the controller by producing the tuning command.
  • the controller can be disabled by the switching circuit and, then, the automatic tuning circuit can automatically set the control parameter of the controller by producing the tuning command.
  • the automatic tuning circuit can transmit an appropriate driving signal to the let-off motor, find the transfer function of the mechanical system from the let-off motor to the warp tension by monitoring variations with time of the warp tension caused by the driving signal, determine the optimum control parameter for the transfer function, and automatically set it in the controller.
  • the switcher switching circuit
  • the tuning command should be generated by manual operation or by appropriate automatic means.
  • the automatic tuning circuit may include a proportional controller which generates a driving signal to be delivered to the let-off motor based on the deviation of the warp tension with respect to the target tension, and a tension data detector which detects variations in the warp tension caused by the driving signal fed from the proportional controller.
  • the automatic tuning circuit may include a signal generator which generates a driving signal to be delivered to the let-off motor, and a regression analyzer which performs regression analysis of variations in the warp tension caused by the driving signal fed from the signal generator.
  • the automatic tuning circuit finds and analyzes a step response of a feedback control system formed of the proportional controller and a controlled system by means of the tension data detector, and thus determines the transfer function of the controlled system, and find the optimum control parameter.
  • the automatic tuning circuit can perform regression analysis of the variations in the warp tension by means of the regression analyzer after the signal generator has transmitted the driving signal to the let-off motor, determine the transfer function of the controlled system using results of the analysis, and find the optimum control parameter.
  • the driving signal output from the signal generator to the let-off motor may be of a fixed level maintained for a specific time period so that appropriate variations with time of the warp tension would be obtained.
  • the let-off control device may further comprise a compensating circuit for improving response to the target tension.
  • the compensating circuit would help improve response to the target tension. It forms a control system having two degrees of freedom together with the controller and would optimize response of the controller not only to external disturbances but also to variations in the warp tension.
  • a let-off control device 10 of a weaving machine comprises as its principal elements a basic speed calculator 11, a controller 14, a control amplifier 17 and an average tension calculator 18. An output of the control device 10 is connected to a let-off motor M.
  • the let-off motor M is connected to a warp beam WB via a reduction gear unit GD.
  • Warp threads W fed from the warp beam WB are pulled out over a tension roller TR and separated into two sets of warp threads, upper warp threads W1 and lower warp threads W2, by a heddle which is not illustrated.
  • the tension roller TR is associated with a detector LD, such as a load cell, which detects warp tension Y exerted on the tension roller TR on a real-time basis.
  • the warp beam WB is associated with a winding diameter sensor DS which detects winding diameter D of (the warp W on) the warp beam WB.
  • Weft density A of an in-process fabric, gear ratio m of the reduction gear unit GD, rotational speed N of the weaving machine and the winding diameter D fed from the winding diameter sensor DS are entered to the basic speed calculator 11, where the weft density A and the gear ratio m are set on an unillustrated setter while the rotational speed N of the weaving machine is output from an unillustrated rotational speed detector.
  • An output of a target tension setter 12 is connected to the controller 14 via an summing point 13. Also, an output of the controller 14 is connected to the let-off motor M via a correction calculator 15, an summing point 16 and the control amplifier 17. Outputs of the average tension calculator 18 and the basic speed calculator 11 are connected to a subtracting terminal of the summing point 13 and to an adding terminal of the summing point 16, respectively. An output of a tachometer generator TG which is directly connected to the let-off motor M is fed back to the control amplifier 17. Further, a clock signal Sc is input from an unillustrated clock generator to the controller 14, and data on the winding diameter D output from the winding diameter sensor DS branches off and is entered to the correction calculator 15.
  • a main shaft MS of the weaving machine is associated with a dog MS1, and a proximity switch DT is disposed face to face with the dog MS1.
  • An output of the proximity switch DT is connected to the average tension calculator 18, to which the warp tension Y is entered from the detector LD.
  • the controller 14 has control elements for performing proportional, integral and differential (control) actions, for instance. It operates in synchronism with a specific operating cycle according to the clock signal Sc and thereby calculates speed correction value Vc based on the deviation ⁇ Ya.
  • the controller 14 performs sampling control operation according to the clock signal Sc, wherein control parameters of the individual control elements, such as proportional gain, integration time constant (integral gain) and differentiation time constant (differential gain), are optimally set with respect to maximum winding diameter Do of the warp W on the warp beam WB.
  • a signal corresponding to a summation, "Vo + Vc1 (a summation of a basic speed Vo fed from the basic speed calculator 11 and a speed correction value Vc1 fed from the correction calculator 15)" is input to a summing point 16 and then a signal corresponding to the summation value is output to the control amplifier 17.
  • the tachometer generator TG detects rotational speed Vm of the let-off motor M and feeds it back to the control amplifier 17, thereby constituting a speed minor loop.
  • the average tension calculator 18 is caused to operate once every rotation of the main shaft MS through the dog MS1 and the proximity switch DT.
  • the controller 14 operates in synchronism with the operating cycle determined by the clock signal Sc which is generated at fixed rate, independently of the operating cycle of the average tension calculator 18. Therefore, there is not any likelihood that the substantial control parameters will fluctuate due to variations in the rotational speed N of the weaving machine.
  • pulse frequency of the clock signal Sc be determined such that the operating cycle of the controller 14 becomes smaller than the operating cycle of the average tension calculator 18 which is determined by the rotational speed N of the weaving machine.
  • the control device 10 of FIG. 1 may further comprises a switching circuit 19 and an automatic tuning circuit 20 as shown in FIGS. 2 and 3.
  • the switching circuit 19 is inserted between the correction calculator 15 and the summing point 16.
  • a tuning command St is entered from an unillustrated weaving machine control circuit. This tuning command St is further delivered to the automatic tuning circuit 20 and to the correction calculator 15 and the switching circuit 19 through the automatic tuning circuit 20.
  • the aforementioned warp tension Y and simulated target tension Ys fed from an unillustrated step signal generator are entered to a proportional controller 21 of the automatic tuning circuit 20, and an output signal of the proportional controller 21 is entered to another adding terminal of the summing point 16 as a driving signal Sd.
  • the warp tension Y branches off and is entered to a tension data detector 22 of the automatic tuning circuit 20 as well, and an output of the tension data detector 22 is connected to the controller 14 of the control device 10 via a transfer function calculator 23 and a parameter setter 24.
  • the tuning command St branches off and is entered to the proportional controller 21 and the tension data detector 22 as well.
  • the switching circuit 19 disconnects the summing point 16 from the correction calculator 15 and substantially disables the controller 14 as a consequence.
  • the proportional controller 21 of this embodiment forms a direct feedback control system for a controlled system from the let-off motor M to the warp tension Y as shown in FIG. 4, in which g represents proportional gain, F(s) represents a transfer function of the controlled system, and s represents a Laplacian operator.
  • the proportional gain g of the proportional controller 21 is properly set such that the warp tension Y exhibits an apparent peak value Ym and the peak value Ym would not diverge.
  • transfer function F2(s), which excludes the integral element, of a mechanical system is calculated from the number of rotations of the warp beam WB as follows:
  • Transfer function Fo(s) of the actual controlled system can be expressed as a first-order lag of a time constant T associated with the delay time T1 as follows:
  • Fo(s) Ko e -sT1 (1/(1 + Ts))
  • (7a) to (7c) are for optimizing response to external disturbances while (8a) to (8c) are for optimizing response to a target value.
  • the tension data detector 22 collects data on variations with time of the warp tension Y caused by the driving signal Sd throughout the time period t ⁇ 0 and outputs the delay time T1, the peak value Ym of the warp tension Y and the final value Y2 to the transfer function calculator 23.
  • the transfer function calculator 23 can determine the transfer function F(s) using equations (1) to (4) and further determine the transfer function Fo(s) using equations (5) and (6).
  • the parameter setter 24 can calculate the optimum control parameter PD for the transfer function Fo(s) using equations (7a) to (7c) or (8a) to (8c) and update set it to the controller 14.
  • the controller 14 is then caused to resume its operation by resetting the tuning command St and thereby closing the switching circuit 19.
  • the delay time T1 output from the tension data detector 22 is delivered up to the parameter setter 24.
  • the automatic tuning circuit 20 may include a signal generator 25 and a regression analyzer 26 instead of the proportional controller 21 and the tension data detector 22 as shown in FIG. 6.
  • the warp tension Y is entered to the regression analyzer 26 and an output of the signal generator 25 is delivered to the summing point 16 as a driving signal Sd for the let-off motor M.
  • the output of the signal generator 25 branches off and is entered to the transfer function calculator 23 as well.
  • the tuning command St branches off and is entered to the regression analyzer 26 and the signal generator 25, and an output of the regression analyzer 26 is delivered up to the transfer function calculator 23.
  • the transfer function Fo(s) of the actual controlled system containing the delay time T1 can be determined from equations (5) and (6) and, then, the optimum control parameter PD of the controller 14 for the transfer function Fo(s) can be calculated from equations (7a) to (7c) or (8a) to (8c).
  • a solid line shows an example of an actual time-varying curve of the warp tension Y and a broken line shows an example of plotting obtained from equation (9) by regression analysis of the time-varying curve.
  • the level V1 of the driving signal Sd and signal length ⁇ are properly set such that the let-off motor M turns the warp beam WB in its forward running direction and the warp tension Y smoothly varies from the initial value Y3 to the final value Y4 which is not equal to 0.
  • the transfer function calculator 23 can determine the parameter ⁇ using the parameters ⁇ and B fed from the regression analyzer 26 and the level V1 of the driving signal Sd fed from the signal generator 25 and then determine the transfer function Fo(s) of the actual controlled system containing the delay time T1 from equations (5) and (6), wherein the delay time T1 can be obtained from the regression analyzer 26 as part of the data on variations with time of the warp tension Y (FIG. 7). Therefore, the parameter setter 24 may calculate the optimum control parameter PD of the controller 14 and set it to the controller 14, and the controller 14 may resume its operation when the switching circuit 19 is closed by resetting the tuning command St in exactly the same way as described above.
  • the tuning command St is generated by manual operation at the time of, such as, replacement of the warp beam, in the foregoing discussion, it may be produced by appropriate automatic means. For example, provision may be made to monitor one or more parameters, such as the winding diameter D of the warp W on the warp beam WB or the deviation ⁇ Ya of the warp tension Y, which could influence let-off control operation, and when any of these parameters considerably varies with time, the tuning command St may be produced automatically generated based on a judgment that tuning operation needs to be performed again.
  • a compensating circuit 31 may be inserted between the target tension setter 12 and the summing point 13 as shown in FIG. 8.
  • the compensating circuit 31 forms a control system having two degrees of freedom together with the controller 14.
  • the compensating circuit 31 can improve response to the target tension Yo by incorporating control elements for performing proportional and differential (control) actions with the same proportional gain Kp and differentiation time constant Td as those of the controller 14 and also optimize response to a target value.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Looms (AREA)
EP00120680A 1999-10-07 2000-09-21 Ablass-Steuervorrichtung für Webmaschinen Withdrawn EP1091032A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP28743299 1999-10-07
JP28743299A JP3542748B2 (ja) 1999-10-07 1999-10-07 織機の送出し制御装置

Publications (2)

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EP1091032A2 true EP1091032A2 (de) 2001-04-11
EP1091032A3 EP1091032A3 (de) 2003-10-01

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023147168A3 (en) * 2022-01-31 2023-09-14 Unspun, Inc Manufacturing woven textile products on demand

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4098150B2 (ja) * 2003-05-09 2008-06-11 津田駒工業株式会社 織機の織段防止装置
JP4851495B2 (ja) * 2008-06-06 2012-01-11 津田駒工業株式会社 織機の経糸制御装置

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH654351A5 (en) * 1981-12-17 1986-02-14 Regatron Ag Method for regulating the warp tension in a weaving machine and warp let-off device for carrying out the method
US4619294A (en) * 1984-01-20 1986-10-28 Tsudakoma Corp. Method of and apparatus for controlling motor-driven let-off and take-up system for looms
JPH01148842A (ja) * 1987-11-28 1989-06-12 Toyota Central Res & Dev Lab Inc 緯糸密度制御装置
EP0376338A2 (de) * 1988-12-28 1990-07-04 Kabushiki Kaisha Toyota Chuo Kenkyusho Keltzuführkontrolleinrichtung für eine Webmaschine

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH654351A5 (en) * 1981-12-17 1986-02-14 Regatron Ag Method for regulating the warp tension in a weaving machine and warp let-off device for carrying out the method
US4619294A (en) * 1984-01-20 1986-10-28 Tsudakoma Corp. Method of and apparatus for controlling motor-driven let-off and take-up system for looms
JPH01148842A (ja) * 1987-11-28 1989-06-12 Toyota Central Res & Dev Lab Inc 緯糸密度制御装置
EP0376338A2 (de) * 1988-12-28 1990-07-04 Kabushiki Kaisha Toyota Chuo Kenkyusho Keltzuführkontrolleinrichtung für eine Webmaschine

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 2000, no. 18, 5 June 2001 (2001-06-05) & JP 01 148842 A (TOYOTA CENTRAL RES & DEV LAB INC;TOYOTA AUTOM LOOM WORKS LTD), 12 June 1989 (1989-06-12) *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023147168A3 (en) * 2022-01-31 2023-09-14 Unspun, Inc Manufacturing woven textile products on demand

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Publication number Publication date
JP2001115364A (ja) 2001-04-24
EP1091032A3 (de) 2003-10-01
JP3542748B2 (ja) 2004-07-14

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