Data processing: generic control systems or specific application – Specific application – apparatus or process – Product assembly or manufacturing
Reexamination Certificate
1999-01-15
2001-11-06
Nerbun, Peter (Department: 3765)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Product assembly or manufacturing
C139S00100C, C706S900000, C706S904000
Reexamination Certificate
active
06314335
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fuzzy control apparatus for the rotational frequency of a motor in an air jet loom, a water jet loom or the like.
2. Description of the Prior Art
In a loom or weaving machine, it is desired to set the rotational frequency of a motor as a prime mover to an optimum value. To this end, a technique has been proposed wherein the rotational frequency of a motor connected to a main shaft is varied in response to an arriving timing at which a weft yarn arrives at a predetermined position, and is disclosed, for example, in Japanese Patent Appln. Public Disclosure (KOKAI) No. 56-107046. However, determination of an optimum rotational frequency relies much upon perception and the experience of the operator. Accordingly, it is difficult to automate the control of the rotational frequency.
For example, where the arriving timing has an early average value and has a large dispersion, the rotational frequency must be raised due to the early average value while the rotational frequency must be lowered due to the large dispersion, and the two controlling directions are opposite to each other. Further, even if an identical weft yarn is used, its characteristic is different delicately whether it is inserted in a test weaving stage or it is inserted in an actual product weaving stage. Furthermore, since the productivity of a woven fabric sometimes decreases as the rotational frequency increases but increases as the rotational frequency decreases, the productivity of a woven fabric must be taken into consideration to modify the rotational frequency. From those reasons, it is very difficult to determine an appropriate rotational frequency or an appropriate modification amount to the rotational frequency of a motor.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a fuzzy control apparatus which can control a jet loom to operate with an optimum rotational frequency or rotational speed determined taking the stability of insertion of a weft yarn and the productivity of a woven fabric into consideration.
In order to attain the object described above, according to the present invention, there is provided a fuzzy control apparatus for a jet loom, comprising flying state detection means for detecting a flying state of a weft yarn, fuzzy inference means for performing fuzzy inference to determine a modification amount to a rotational frequency of a motor based on a detection value detected by the detection means, and control means for driving the motor to rotate at a predetermined rotational frequency or speed and correcting the rotational frequency of the motor based on the modification amount.
The flying state of the weft yarn may be any of average values and dispersions of a timing of weft yarn releasing from a metering storage apparatus, an arriving timing of a weft yarn, a flying speed of a weft yarn, an arriving time (flying time) of a weft yarn at a predetermined position after starting of the flying, and so forth, or any combination of them. The fuzzy inference means performs, based on an actual value of such a flying condition, fuzzy inference for determining a fuzzy set using a plurality of membership functions and a plurality of fuzzy control rules to determine a modification amount to the rotational frequency of the motor.
Consequently, with the fuzzy control apparatus, a correct modification value to the rotational frequency can be obtained without relying upon perception or the experience of the operator, and the loom can be operated with an optimum rotational frequency determined taking the stability of weft yarn insertion and the productivity of a woven fabric into consideration.
The fuzzy control apparatus may be constructed such that the fuzzy inference means further determines, based on the detection value, a modification value to a pressure of weft yarn inserting fluid to be supplied to a weft yarn inserting nozzle, and the control means further supplies the weft yarn inserting fluid at a predetermined pressure to the weft yarn inserting nozzle and corrects the pressure of the weft yarn inserting fluid based on the modification value to the pressure. With the fuzzy control apparatus, a correct modification value to the pressure of the weft yarn inserting pressure fluid can also be obtained without relying upon perception or the experience of the operator, and as a result, weft yarn insertion is stabilized.
The fuzzy control apparatus may be further constructed such that the control means drives the motor to rotate at a reference rotational frequency set in advance and corrects the rotational frequency of the motor based on the modification amount, and supplies the weft yarn inserting fluid at a reference pressure set in advance to the weft yarn inserting nozzle and corrects the pressure of the weft yarn inserting fluid based on the modification amount to the pressure. The fuzzy control means for the rotational frequency and the fuzzy control means for the pressure can be formed as a common control circuit.
The above and other objects, features and advantages of the present invention will become apparent from the following description and the appended claims, taken in conjunction with the accompanying drawings in which like parts or elements are denoted by like reference symbols.
REFERENCES:
patent: 4458726 (1984-07-01), Wenig
patent: 5115840 (1992-05-01), Yamada
patent: 5134568 (1992-07-01), Sainen
patent: 5322089 (1994-06-01), Yamada
patent: 5440495 (1995-08-01), Sainen et al.
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European Search Report, dated Dec. 21, 1999.
Sainen Tsutomu
Tamura Zenji
Nerbun Peter
Tsudakoma Kogyo Kabushiki Kaisha
Webb Ziesenheim & Logsdon Orkin & Hanson, P.C.
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