1. A yarn winding machine (1) comprising: a yarn supplying section (18) capable of supplying a yarn (5); a winding section (30) that traverses and winds the yarn (5) supplied from the yarn supplying section (18) to form a package (8); a speed acquiring section (17) that acquires a running speed of the yarn (5) running from the yarn supplying section (18) toward the winding section (30); and an error detecting section (11) that detects an error relating to winding of the yarn (5) based on the running speed acquired by the speed acquiring section (17), wherein the error detecting section (11) identifies, as a singular point, at least one between a local maximum value and a local minimum value that fulfills a predetermined condition among one between local maximum values or local minimum values that appear with a change in the running speed over time; local maximum values or local minimum values that appear with a change in a speed ratio over time obtained by dividing the running speed by a speed relating to a circumferential speed of the package (8), and detects an error based on an appearance interval at which the singular point appears.

2. The yarn winding machine (1) as claimed in Claim 1, comprising a setting section (3) that sets a reference interval, wherein the error detecting section (11) identifies, considering that one between a local maximum value and a local minimum value that appears in the reference interval fulfills a predetermined condition, the one between the local maximum value and the local minimum value as the singular point.

3. The yarn winding machine (1) as claimed in Claim 2, wherein the reference interval is defined based on a predetermined yarn length that is wound by the winding section (30) when the yarn (5) is moved from end to end of the package (8) by the winding section (30) by traversing the yarn (5), and the predetermined yarn length is a constant length regardless of the running speed.

4. The yarn winding machine (1) as claimed in Claim 2 or 3, wherein the setting section (3) sets a normal range for a point advanced by the reference interval from a predetermined singular point, and the error detecting section (11) identifies, considering that one between a local maximum value and a local minimum value that exists within the normal range fulfills a predetermined condition, the one between the local maximum value and the local minimum value as the singular point.

5. The yarn winding machine (1) as claimed in Claim 4, wherein the error detecting section (11) judges that the error has occurred when, in the normal range set continuously for a first number, number of times the local maximum value or the local minimum value does not appear within the normal range fulfills an error condition in which a second number is exceeded.

6. The yarn winding machine (1) as claimed in Claim 4, wherein the error detecting section (11) sets an estimated point within the normal range when the local maximum value or the local minimum value does not exist within the normal range, and judges that an error has occurred when, in the normal range set continuously for the first number, number of times the estimated point is set fulfills an error condition in which the second number is exceeded.

7. The yarn winding machine (1) as claimed in Claim 6, comprising a catching section (20) that catches a problematic portion of the yarn (5) that forms the package (8), wherein the error detecting section (11) calculates a length of the problematic portion based on the estimated point, and the catching section (20) catches from the package (8) only the problematic portion of the length calculated by the error detecting section (11).

8. The yarn winding machine (1) as claimed in one of Claims 2 to 7, wherein the setting section (3) updates the reference interval based on the past appearance interval.

9. The yarn winding machine (1) as claimed in one of Claims 1 to 8 comprising: a storage section that stores therein one between a maximum value and a minimum value of the running speed; and an update section that compares, when the maximum value is stored in the storage section, the running speed that is newly acquired by the speed acquiring section (17) and the maximum value stored in the storage section and updates the maximum value stored in the storage section with a new maximum value when the new running speed is larger than the stored maximum value, or compares, when the minimum value is stored in the storage section, the running speed that is newly acquired by the speed acquiring section (17) and the minimum value stored in the storage section, and updates the minimum value stored in the storage section with a new minimum value when the newly acquired running speed is larger than the stored minimum value, wherein the error detecting section (11) identifies the maximum value or the minimum value stored in the storage section as a local maximum value or a local minimum value when a predetermined difference occurs between a first position of the yarn (5) at the time at which the new running speed is acquired by the speed acquiring section (17) and a second position of the yarn (5) at the time at which the maximum value or the minimum value is updated by the update section.

10. The yarn winding machine (1) as claimed in one of Claims 1 to 9, wherein the error detecting section (11) judges that the error has occurred when the appearance interval changes.

11. A yarn winding machine (1) comprising: a yarn supplying section (18) capable of supplying a yarn (5); a winding section (30) that traverses and winds the yarn (5) supplied from the yarn supplying section (18) to form a package (8); a speed acquiring section (17) that acquires a running speed of the yarn (5) running from the yarn supplying section (18) toward the winding section (30); and an error detecting section (11) that detects an error relating to winding of the yarn (5) based on the running speed of the yarn (5) acquired by the speed acquiring section (17), wherein the error detecting section (11) identifies, as a first singular point and a second singular point, respectively, a local maximum value and a local minimum value that fulfill a predetermined condition among one between local maximum values and local minimum values that appear with a change in the running speed over time; local maximum values and local minimum values that appear with a change in a speed ratio over time obtained by dividing the running speed by a speed relating to a circumferential speed of the package (8), and detects an error based on a difference between the first singular point and the second singular point nearest to the corresponding first singular point.

12. The yarn winding machine (1) as claimed in Claim 11, comprising a setting section (3) that sets a reference interval, wherein the error detecting section (11) identifies, considering that a local maximum value and a local minimum value that appear in the reference interval fulfill the predetermined condition, the local maximum value and the local minimum value as the first singular point and the second singular point, respectively.

13. The yarn winding machine (1) as claimed in Claim 12, wherein the reference interval is defined based on a predetermined yarn length that is wound by the winding section (30) when the winding section (30) moves the yarn (5) from end to end of a package (8) by traversing the yarn (5), and the predetermined yarn length is a constant length regardless of the running speed.

14. The yarn winding machine (1) as claimed in Claim 12 or 13, wherein the setting section (3) sets a normal range for a point offset from a predetermined singular point by the reference interval, and the error detecting section (11) identifies, considering that a local maximum value and a local minimum value that exist within the normal range fulfill the predetermined condition, the local maximum value and the local minimum value as the first singular point and the second singular point, respectively.

15. The yarn winding machine (1) as claimed in one of Claims 11 to 14 comprising: a storage section that stores therein a maximum value and a minimum value of a running speed, and an update section that compares a new running speed acquired by the speed acquiring section (17) with the maximum value and the minimum value stored in the storage section and updates the maximum value or the minimum value stored in the storage section as a new maximum value or a new minimum value when the new running speed is larger than the maximum value or smaller than the minimum value, wherein the error detecting section (11) identifies the maximum value or the minimum value stored in the storage section as a local maximum value or a local minimum value, when a predetermined difference occurs between a first position of the yarn (5) at the time at which a new running speed is acquired by the speed acquiring section (17) and a second position of the yarn (5) at the time at which a maximum value or a minimum value is updated by the update section.

16. The yarn winding machine (1) as claimed in one of Claims 11 to 15, wherein the error detecting section (11) judges that an error has occurred when a difference between the first singular point and the second singular point nearest to the corresponding first singular point is less than or equal to a threshold value.

17. The yarn winding machine (1) as claimed in one of Claims 11 to 16, wherein the error detecting section (11) judges that an error has occurred when at least one between the first singular point and the second singular point cannot be identified while a yarn length relating to error determination is being wound.

18. The yarn winding machine (1) as claimed in one of Claims 11 to 16, wherein the error detecting section (11) judges that an error has occurred when at least one between the local maximum value and the local minimum value cannot be identified while a yarn length relating to error determination is being wound.

19. The yarn winding machine (1) as claimed in one of Claims 11 to 18, comprising: a yarn joining device (16) that performs a yarn joining operation to make the yarn (5) continuous when the yarn (5) splits between the yarn supplying section (18) and the winding section (30); and a catching section (19, 20) that catches a problematic portion of the yarn (5) that forms the package (8), wherein upon detecting that the error has occurred, the error detecting section (11) calculates a running distance of the yarn (5) from when yarn joining operation is performed in the yarn joining device up to when the error is detected, and the catching section (19, 20) catches the problematic portion of the yarn (5) of the length equivalent to the running distance from the package (8).

20. The yarn winding machine (1) as claimed in one of Claims 1 to 19, comprising a tension detecting section (15) that detects tension applied onto the yarn (5) running from the yarn supplying section (18) toward the winding section (30), wherein the speed acquiring section (17) acquires the running speed based on the tension of the yarn (5) detected by the tension detecting section (15).

21. A yarn winding machine (1) comprising: a yarn supplying section (18) capable of supplying a yarn (5); a winding section (30) that traverses and winds the yarn (5) supplied from the yarn supplying section (18) to form a package (8); a tension detecting section (15) that detects tension of the yarn (5) running from the yarn supplying section (18) toward the winding section (30); and an error detecting section (11) that detects an error relating to winding of the yarn (5) based on the tension of the yarn (5) detected by the tension detecting section (15), wherein the error detecting section (11) identifies, as a singular point, one between a local maximum value and a local minimum value that fulfills a predetermined condition among local maximum values and local minimum values that appear in a change in the tension over time, and detects an error based on an appearance interval of the singular point.

22. A yarn winding machine (1) comprising: a yarn supplying section (18) capable of supplying a yarn (5); a winding section (30) that traverses and winds the yarn (5) supplied from the yarn supplying section (18) to form a package (8); a tension detecting section (15) that detects tension of the yarn (5) running from the yarn supplying section (18) toward the winding section (30); and an error detecting section (11) that detects an error relating to winding of the yarn (5) based on the tension of the yarn (5) detected by the tension detecting section (15), wherein the error detecting section (11) identifies, as a first singular point and a second singular point, respectively, a local maximum value and a local minimum value that fulfill a predetermined condition among local maximum values and local minimum values that appear in a change in the tension over time, and detects an error based on a difference between the first singular point and the second singular point nearest to the corresponding first singular point.

23. A winding error detecting method executed by a yarn winding machine (1) that includes a yarn supplying section (18) capable of supplying a yarn (5) and a winding section (30) that traverses and winds the yarn (5) supplied from the yarn supplying section (18) to form a package (8), comprising: speed acquiring in which a running speed of the yarn (5) running from the yarn supplying section (18) toward the winding section (30) is acquired; and error detecting in which an error relating to winding of the yarn (5) is detected based on the running speed acquired via the speed acquiring, wherein the error detecting includes identifying, as a singular point, one between a local maximum value and a local minimum value that fulfills a predetermined condition among one between local maximum values or local minimum values that appear with a change in the running speed over time; local maximum values or local minimum values that appear with a change in a speed ratio over time obtained by dividing the running speed by a speed relating to a circumferential speed of the package (8), and detecting an error based on an appearance interval of the singular point.

24. A winding error detecting method executed by a yarn winding machine (1) that includes a yarn supplying section (18) capable of supplying a yarn (5) and a winding section (30) that traverses and winds the yarn (5) supplied from the yarn supplying section (18) to form a package (8), comprising: speed acquiring in which a running speed of the yarn (5) running from the yarn supplying section (18) toward the winding section (30) is acquired; and error detecting in which an error relating to winding of the yarn (5) is detected based on the running speed acquired in the speed acquiring, wherein the error detecting includes identifying, as a first singular point and a second singular point, respectively, a local maximum value and a local minimum value that fulfill a predetermined condition among one between local maximum values and local minimum values that appear with a change in the running speed over time; local maximum values and local minimum values that appear with a change in a speed ratio over time obtained by dividing the running speed by a speed relating to a circumferential speed of the package (8), and detecting an error based on a difference between the first singular point and the second singular point nearest to the corresponding first singular point.   , Description:BACKGROUND OF THE INVENTION

1. Field of the Invention The present invention relates to a yarn winding machine and a winding error detecting method.

Claims:I/We claim:

1. A yarn winding machine (1) comprising:
a yarn supplying section (18) capable of supplying a yarn (5);
a winding section (30) that traverses and winds the yarn (5) supplied from the yarn supplying section (18) to form a package (8);
a speed acquiring section (17) that acquires a running speed of the yarn (5) running from the yarn supplying section (18) toward the winding section (30); and
an error detecting section (11) that detects an error relating to winding of the yarn (5) based on the running speed acquired by the speed acquiring section (17), wherein
the error detecting section (11)
identifies, as a singular point, at least one between a local maximum value and a local minimum value that fulfills a predetermined condition among one between
local maximum values or local minimum values that appear with a change in the running speed over time;
local maximum values or local minimum values that appear with a change in a speed ratio over time obtained by dividing the running speed by a speed relating to a circumferential speed of the package (8), and
detects an error based on an appearance interval at which the singular point appears.
2. The yarn winding machine (1) as claimed in Claim 1, comprising a setting section (3) that sets a reference interval, wherein
the error detecting section (11) identifies, considering that one between a local maximum value and a local minimum value that appears in the reference interval fulfills a predetermined condition, the one between the local maximum value and the local minimum value as the singular point.

3. The yarn winding machine (1) as claimed in Claim 2, wherein
the reference interval is defined based on a predetermined yarn length that is wound by the winding section (30) when the yarn (5) is moved from end to end of the package (8) by the winding section (30) by traversing the yarn (5), and
the predetermined yarn length is a constant length regardless of the running speed.

4. The yarn winding machine (1) as claimed in Claim 2 or 3, wherein
the setting section (3) sets a normal range for a point advanced by the reference interval from a predetermined singular point, and
the error detecting section (11) identifies, considering that one between a local maximum value and a local minimum value that exists within the normal range fulfills a predetermined condition, the one between the local maximum value and the local minimum value as the singular point.
5. The yarn winding machine (1) as claimed in Claim 4, wherein the error detecting section (11) judges that the error has occurred when, in the normal range set continuously for a first number, number of times the local maximum value or the local minimum value does not appear within the normal range fulfills an error condition in which a second number is exceeded.

6. The yarn winding machine (1) as claimed in Claim 4, wherein the error detecting section (11) sets an estimated point within the normal range when the local maximum value or the local minimum value does not exist within the normal range, and judges that an error has occurred when, in the normal range set continuously for the first number, number of times the estimated point is set fulfills an error condition in which the second number is exceeded.

7. The yarn winding machine (1) as claimed in Claim 6, comprising a catching section (20) that catches a problematic portion of the yarn (5) that forms the package (8), wherein
the error detecting section (11) calculates a length of the problematic portion based on the estimated point, and
the catching section (20) catches from the package (8) only the problematic portion of the length calculated by the error detecting section (11).

8. The yarn winding machine (1) as claimed in one of Claims 2 to 7, wherein the setting section (3) updates the reference interval based on the past appearance interval.

9. The yarn winding machine (1) as claimed in one of Claims 1 to 8 comprising:
a storage section that stores therein one between a maximum value and a minimum value of the running speed; and
an update section that compares, when the maximum value is stored in the storage section, the running speed that is newly acquired by the speed acquiring section (17) and the maximum value stored in the storage section and updates the maximum value stored in the storage section with a new maximum value when the new running speed is larger than the stored maximum value, or compares, when the minimum value is stored in the storage section, the running speed that is newly acquired by the speed acquiring section (17) and the minimum value stored in the storage section, and updates the minimum value stored in the storage section with a new minimum value when the newly acquired running speed is larger than the stored minimum value, wherein
the error detecting section (11) identifies the maximum value or the minimum value stored in the storage section as a local maximum value or a local minimum value when a predetermined difference occurs between a first position of the yarn (5) at the time at which the new running speed is acquired by the speed acquiring section (17) and a second position of the yarn (5) at the time at which the maximum value or the minimum value is updated by the update section.
10. The yarn winding machine (1) as claimed in one of Claims 1 to 9, wherein the error detecting section (11) judges that the error has occurred when the appearance interval changes.

11. A yarn winding machine (1) comprising:
a yarn supplying section (18) capable of supplying a yarn (5);
a winding section (30) that traverses and winds the yarn (5) supplied from the yarn supplying section (18) to form a package (8);
a speed acquiring section (17) that acquires a running speed of the yarn (5) running from the yarn supplying section (18) toward the winding section (30); and
an error detecting section (11) that detects an error relating to winding of the yarn (5) based on the running speed of the yarn (5) acquired by the speed acquiring section (17), wherein
the error detecting section (11)
identifies, as a first singular point and a second singular point, respectively, a local maximum value and a local minimum value that fulfill a predetermined condition among one between
local maximum values and local minimum values that appear with a change in the running speed over time;
local maximum values and local minimum values that appear with a change in a speed ratio over time obtained by dividing the running speed by a speed relating to a circumferential speed of the package (8), and
detects an error based on a difference between the first singular point and the second singular point nearest to the corresponding first singular point.

12. The yarn winding machine (1) as claimed in Claim 11, comprising a setting section (3) that sets a reference interval, wherein
the error detecting section (11) identifies, considering that a local maximum value and a local minimum value that appear in the reference interval fulfill the predetermined condition, the local maximum value and the local minimum value as the first singular point and the second singular point, respectively.

13. The yarn winding machine (1) as claimed in Claim 12, wherein
the reference interval is defined based on a predetermined yarn length that is wound by the winding section (30) when the winding section (30) moves the yarn (5) from end to end of a package (8) by traversing the yarn (5), and
the predetermined yarn length is a constant length regardless of the running speed.

14. The yarn winding machine (1) as claimed in Claim 12 or 13, wherein
the setting section (3) sets a normal range for a point offset from a predetermined singular point by the reference interval, and
the error detecting section (11) identifies, considering that a local maximum value and a local minimum value that exist within the normal range fulfill the predetermined condition, the local maximum value and the local minimum value as the first singular point and the second singular point, respectively.

15. The yarn winding machine (1) as claimed in one of Claims 11 to 14 comprising:
a storage section that stores therein a maximum value and a minimum value of a running speed, and
an update section that compares a new running speed acquired by the speed acquiring section (17) with the maximum value and the minimum value stored in the storage section and updates the maximum value or the minimum value stored in the storage section as a new maximum value or a new minimum value when the new running speed is larger than the maximum value or smaller than the minimum value, wherein
the error detecting section (11) identifies the maximum value or the minimum value stored in the storage section as a local maximum value or a local minimum value, when a predetermined difference occurs between a first position of the yarn (5) at the time at which a new running speed is acquired by the speed acquiring section (17) and a second position of the yarn (5) at the time at which a maximum value or a minimum value is updated by the update section.

16. The yarn winding machine (1) as claimed in one of Claims 11 to 15, wherein the error detecting section (11) judges that an error has occurred when a difference between the first singular point and the second singular point nearest to the corresponding first singular point is less than or equal to a threshold value.

17. The yarn winding machine (1) as claimed in one of Claims 11 to 16, wherein the error detecting section (11) judges that an error has occurred when at least one between the first singular point and the second singular point cannot be identified while a yarn length relating to error determination is being wound.

18. The yarn winding machine (1) as claimed in one of Claims 11 to 16, wherein the error detecting section (11) judges that an error has occurred when at least one between the local maximum value and the local minimum value cannot be identified while a yarn length relating to error determination is being wound.

19. The yarn winding machine (1) as claimed in one of Claims 11 to 18, comprising:
a yarn joining device (16) that performs a yarn joining operation to make the yarn (5) continuous when the yarn (5) splits between the yarn supplying section (18) and the winding section (30); and
a catching section (19, 20) that catches a problematic portion of the yarn (5) that forms the package (8), wherein
upon detecting that the error has occurred, the error detecting section (11) calculates a running distance of the yarn (5) from when yarn joining operation is performed in the yarn joining device up to when the error is detected, and
the catching section (19, 20) catches the problematic portion of the yarn (5) of the length equivalent to the running distance from the package (8).

20. The yarn winding machine (1) as claimed in one of Claims 1 to 19, comprising a tension detecting section (15) that detects tension applied onto the yarn (5) running from the yarn supplying section (18) toward the winding section (30), wherein
the speed acquiring section (17) acquires the running speed based on the tension of the yarn (5) detected by the tension detecting section (15).

21. A yarn winding machine (1) comprising:
a yarn supplying section (18) capable of supplying a yarn (5);
a winding section (30) that traverses and winds the yarn (5) supplied from the yarn supplying section (18) to form a package (8);
a tension detecting section (15) that detects tension of the yarn (5) running from the yarn supplying section (18) toward the winding section (30); and
an error detecting section (11) that detects an error relating to winding of the yarn (5) based on the tension of the yarn (5) detected by the tension detecting section (15), wherein
the error detecting section (11)
identifies, as a singular point, one between a local maximum value and a local minimum value that fulfills a predetermined condition among local maximum values and local minimum values that appear in a change in the tension over time, and
detects an error based on an appearance interval of the singular point.

22. A yarn winding machine (1) comprising:
a yarn supplying section (18) capable of supplying a yarn (5);
a winding section (30) that traverses and winds the yarn (5) supplied from the yarn supplying section (18) to form a package (8);
a tension detecting section (15) that detects tension of the yarn (5) running from the yarn supplying section (18) toward the winding section (30); and
an error detecting section (11) that detects an error relating to winding of the yarn (5) based on the tension of the yarn (5) detected by the tension detecting section (15), wherein
the error detecting section (11)
identifies, as a first singular point and a second singular point, respectively, a local maximum value and a local minimum value that fulfill a predetermined condition among local maximum values and local minimum values that appear in a change in the tension over time, and
detects an error based on a difference between the first singular point and the second singular point nearest to the corresponding first singular point.

23. A winding error detecting method executed by a yarn winding machine (1) that includes a yarn supplying section (18) capable of supplying a yarn (5) and a winding section (30) that traverses and winds the yarn (5) supplied from the yarn supplying section (18) to form a package (8), comprising:
speed acquiring in which a running speed of the yarn (5) running from the yarn supplying section (18) toward the winding section (30) is acquired; and
error detecting in which an error relating to winding of the yarn (5) is detected based on the running speed acquired via the speed acquiring, wherein
the error detecting includes
identifying, as a singular point, one between a local maximum value and a local minimum value that fulfills a predetermined condition among one between
local maximum values or local minimum values that appear with a change in the running speed over time;
local maximum values or local minimum values that appear with a change in a speed ratio over time obtained by dividing the running speed by a speed relating to a circumferential speed of the package (8), and
detecting an error based on an appearance interval of the singular point.

24. A winding error detecting method executed by a yarn winding machine (1) that includes a yarn supplying section (18) capable of supplying a yarn (5) and a winding section (30) that traverses and winds the yarn (5) supplied from the yarn supplying section (18) to form a package (8), comprising:
speed acquiring in which a running speed of the yarn (5) running from the yarn supplying section (18) toward the winding section (30) is acquired; and
error detecting in which an error relating to winding of the yarn (5) is detected based on the running speed acquired in the speed acquiring, wherein
the error detecting includes
identifying, as a first singular point and a second singular point, respectively, a local maximum value and a local minimum value that fulfill a predetermined condition among one between
local maximum values and local minimum values that appear with a change in the running speed over time;
local maximum values and local minimum values that appear with a change in a speed ratio over time obtained by dividing the running speed by a speed relating to a circumferential speed of the package (8), and
detecting an error based on a difference between the first singular point and the second singular point nearest to the corresponding first singular point.
 
, Description:BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a yarn winding machine and a winding error detecting method.

2. Description of the Related Art
A yarn winding machine is disclosed in Japanese Patent Application Laid-Open No. 2014-24652. This yarn winding machine includes a yarn supplying section that supplies a yarn, a winding section that traverses and winds the yarn supplied from the yarn supplying section to form a package, a detecting device that detects a running speed of the yarn, and an error detecting section that detects presence or absence of yarn winding error based on the detected running speed.

Problem to be solved by the Invention
In Japanese Patent Application Laid-Open No. 2014-24652, occurrence of winding error (traverse error) is detected by focusing on a periodic change in the running speed of the yarn. This method is based on a concept that the periodic change in the running speed of the yarn occurs as a traverse position of the yarn changes during the winding.
Specifically, as disclosed in Japanese Patent Application Laid-Open No. 2014-24652, it is determined that winding error, in which the yarn winds around a winding drum, has occurred when the number of times the periodic change occurs in the running speed within a predetermined range is less than or equal to a predetermined number. Moreover, it is determined that a winding error, in which a drive point (a drive point at which the winding drum transmits the rotational driving force to a package) is inclined and the possibility of cob webbing has increased, has occurred when the periodic change in the running speed is inclining toward a high speed side or a low speed side than that at the normal time.

SUMMARY OF THE INVENTION
However, a specific method for detecting the periodic change in a running speed is not disclosed in Japanese Patent Application Laid-Open No. 2014-24652. The inventor of the present invention found that local maximum values or local minimum values of various magnitudes appear with a change in the running speed over time, and it is difficult to accurately detect the periodic change in the running speed in some cases. Specifically, the inventor found that it is difficult to accurately calculate the frequency of the periodic change based on local maximum values or local minimum values of various magnitudes. In view of this, a yarn winding machine that accurately detects a yarn winding error is desired.
One aspect of the present invention is to provide a yarn winding machine and a winding error detecting method that can accurately detect a yarn winding error.
According to one aspect of the present invention, a yarn winding machine includes a yarn supplying section capable of supplying a yarn; a winding section that traverses and winds the yarn supplied from the yarn supplying section to form a package; a speed acquiring section that acquires a running speed of the yarn running from the yarn supplying section toward the winding section; and an error detecting section that detects an error relating to winding of the yarn based on the running speed acquired by the speed acquiring section. The error detecting section identifies, as a singular point, at least one between a local maximum value and a local minimum value that fulfills a predetermined condition among one between local maximum values or local minimum values that appear with a change in the running speed over time; local maximum values or local minimum values that appear with a change in a speed ratio over time obtained by dividing the running speed by a speed relating to a circumferential speed of the package, and detects an error based on an appearance interval at which the singular point appears.
According to another aspect of the present invention, a yarn winding machine includes a yarn supplying section capable of supplying a yarn; a winding section that traverses and winds the yarn supplied from the yarn supplying section to form a package; a speed acquiring section that acquires a running speed of the yarn running from the yarn supplying section toward the winding section; and an error detecting section that detects an error relating to winding of the yarn based on the running speed of the yarn acquired by the speed acquiring section. The error detecting section identifies, as a first singular point and a second singular point, respectively, a local maximum value and a local minimum value that fulfill a predetermined condition among one between local maximum values and local minimum values that appear with a change in the running speed over time; local maximum values and local minimum values that appear with a change in a speed ratio over time obtained by dividing the running speed acquired by the speed acquiring section by a speed relating to a circumferential speed of the package, and detects an error based on a difference between the first singular point and the second singular point nearest to the corresponding first singular point.
According to still another aspect of the present invention, a yarn winding machine includes a yarn supplying section capable of supplying a yarn; a winding section that traverses and winds the yarn supplied from the yarn supplying section to form a package; a tension detecting section that detects tension of the yarn running from the yarn supplying section toward the winding section; and an error detecting section that detects an error relating to winding of the yarn based on the tension of the yarn detected by the tension detecting section. The error detecting section identifies, as a singular point, one between a local maximum value and a local minimum value that fulfills a predetermined condition among local maximum values and local minimum values that appear in a change in the tension over time, and detects an error based on an appearance interval of the singular point.
According to still another aspect of the present invention, a yarn winding machine includes a yarn supplying section capable of supplying a yarn; a winding section that traverses and winds the yarn supplied from the yarn supplying section to form a package; a tension detecting section that detects tension of the yarn running from the yarn supplying section toward the winding section; and an error detecting section that detects an error relating to winding of the yarn based on the tension of the yarn detected by the tension detecting section. The error detecting section identifies, as a first singular point and a second singular point, respectively, a local maximum value and a local minimum value that fulfill a predetermined condition among local maximum values and local minimum values that appear in a change in the tension over time, and detects an error based on a difference between the first singular point and the second singular point nearest to the corresponding first singular point.
According to still another aspect of the present invention, a winding error detecting method executed by a yarn winding machine that includes a yarn supplying section capable of supplying a yarn and a winding section that traverses and winds the yarn supplied from the yarn supplying section to form a package, includes speed acquiring in which a running speed of the yarn running from the yarn supplying section toward the winding section is acquired; and error detecting in which an error relating to winding of the yarn is detected based on the running speed acquired via the speed acquiring. The error detecting includes identifying, as a singular point, one between a local maximum value and a local minimum value that fulfills a predetermined condition among one between local maximum values or local minimum values that appear with a change in the running speed over time; local maximum values or local minimum values that appear with a change in a speed ratio over time obtained by dividing the running speed by a speed relating to a circumferential speed of the package, and detecting an error based on an appearance interval of the singular point.
According to still another aspect of the present invention, a winding error detecting method executed by a yarn winding machine that includes a yarn supplying section capable of supplying a yarn and a winding section that traverses and winds the yarn supplied from the yarn supplying section to form a package, includes speed acquiring in which a running speed of the yarn running from the yarn supplying section toward the winding section is acquired; and error detecting in which an error relating to winding of the yarn is detected based on the running speed acquired in the speed acquiring. The error detecting includes identifying, as a first singular point and a second singular point, respectively, a local maximum value and a local minimum value that fulfill a predetermined condition among one between local maximum values and local minimum values that appear with a change in the running speed over time; local maximum values and local minimum values that appear with a change in a speed ratio over time obtained by dividing the running speed by a speed relating to a circumferential speed of the package, and detecting an error based on a difference between the first singular point and the second singular point nearest to the corresponding first singular point.
The above and other objects, features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view of an automatic winder according to an embodiment of the present invention.
FIG. 2 is a front view of a winding unit that is included in a spinning machine shown in FIG. 1.
FIG. 3A is a graph showing a running speed of a yarn with respect to time, and FIG. 3B is a graph showing a speed ratio with respect to time.
FIG. 4 is another graph showing a speed ratio with respect to time.
FIG. 5 shows a method to set an estimated local value.
FIG. 6 is a diagram showing a judgement result and a traverse error rate.
FIG. 7A is a graph showing a relation between a speed ratio and time in a normal state, and FIG. 7B is a diagram showing a relation between a speed ratio and time in a state in which a straight winding error has occurred.
FIG. 8A is a diagram showing a state in which straight winding has occurred on a package, and FIG. 8B is a diagram showing a state in which stepped winding has occurred on a package.

DETAILED DESCRIPTION
Exemplary embodiments of the present invention are explained in detail below with reference to the accompanying drawings. Identical elements or corresponding elements are indicated by the same reference symbols in the drawings and redundant explanation thereof is omitted.
As shown in FIG. 1, an automatic winder 1 (yarn winding machine) includes a main control device 2, a plurality of winding units 10, and a doffing device 40.
The main control device 2 includes a setting section 3 and a display panel (notification section) 4. By using the setting section 3 to perform appropriate operations, an operator can perform settings of the winding unit 10. The display panel 4 can display information about settings and / or a state of the winding unit 10 and the like.
The plurality of the winding units 10 is arranged, for example, in a row. In each winding unit 10, a yarn 5 is unwound from a supply bobbin 6 and wound onto a winding bobbin 7 (see FIG. 2) while traversing the yarn 5 to form a package 8. The winding bobbin 7 and the package 8 can have various sizes and shapes. For example, the winding bobbin 7 and the package 8 can be of a truncated cone shape (cone shape) or a cylindrical shape. In the present embodiment, the winding bobbin 7 and the package 8 are arranged above the supply bobbin 6 in the machine height direction and the yarn 5 runs from a lower side to an upper side.
As shown in FIG. 2, the winding unit 10 includes a unit controller (error detecting section) 11 and a unit main body 12. The unit controller 11 includes, for example, a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), an I/O port, and a communication port. A computer program to control various structural components of the unit main body 12 is stored in the ROM. Various devices included in the unit main body 12 and the main control device 2 are connected to the I/O port and the communication port. Accordingly, the unit controller 11 can control operations of various devices in the unit main body 12 while communicating with the main control device 2. Moreover, the unit controller 11 includes a storage section and an update section explained later. Furthermore, the storage section and the update section can be provided outside the unit controller 11.
The unit main body 12 includes, in a running path of the yarn 5 from the supply bobbin 6 to the winding bobbin 7 and the package 8, sequentially from the supply bobbin 6, a yarn unwinding assisting device 13, a tension applying device 14, a tension detecting device (tension detecting section) 15, a yarn joining device 16, and a yarn monitoring device (speed acquiring section) 17. A yarn supplying section 18 is arranged below the unit main body 12. The yarn supplying section 18 holds the supply bobbin 6 that is transported by a not-shown bobbin conveying system at a predetermined position. Alternatively, the yarn supplying section 18 can be configured to hold the supply bobbin 6 that is manually supplied by the operator at a predetermined position.
The yarn unwinding assisting device 13 assists in smooth unwinding of the yarn 5 by controlling a balloon formed by the yarn 5, when the yarn 5 is unwound from the supply bobbin 6, to an appropriate size. The tension applying device 14 applies a predetermined tension onto the running yarn 5. As the tension applying device 14, a gate type device, a disk type device, and the like can be used. The tension detecting device 15 detects (measures) the tension applied onto the running yarn 5 between the yarn supplying section 18 and the winding device 30 (tension detecting). The tension detecting device 15 outputs to the unit controller 11 a tension measurement signal that indicates a measured value of the tension applied onto the yarn 5. When a yarn is cut after the yarn monitoring device 17 has detected a yarn defect, or when the yarn breaks during unwinding thereof from the supply bobbin 6 and the like, the yarn joining device 16 performs yarn joining of a lower yarn from the supply bobbin 6 and an upper yarn from the package 8. As the yarn joining device 16, a mechanical knotter or a splicer that uses fluids, such as compressed air and the like, can be used.
The yarn monitoring device 17 detects a state of the yarn 5 wound onto the package 8. The yarn monitoring device 17 detects, for example, a yarn defect, such as a slub, by detecting a thickness of the yarn 5. The yarn monitoring device 17 can detect, as the yarn defect, an error in the thickness of the yarn 5, presence or absence of a foreign matter in the yarn 5, and the like. The yarn monitoring device 17 can include a cutter to cut the yarn 5 when the yarn defect is detected. The yarn monitoring device 17 detects a speed of the running yarn 5 (speed acquiring). The yarn monitoring device 17 detects and acquires a running speed of the yarn 5 that runs from the supply bobbin 6 toward the winding device 30. The yarn monitoring device 17 outputs, to the unit controller 11, speed data relating to the running speed of the yarn 5. The speed data is, for example, a pulse signal that changes during a period corresponding to the running speed of the yarn 5. The speed data can be calculated, for example, based on the running amount of the yarn running per unit time. Alternatively, the speed data can be calculated based on the time per unit running amount of the running yarn 5. As another method, the yarn monitoring device 17 can measure a winding length of the yarn 5 based on speed data.
The storage section stores therein the running speed of the yarn 5 detected by the yarn monitoring device 17, a maximum value and a minimum value (explained later) of the running speed, and a local maximum value and a local minimum value.
A lower yarn catching member 19 that catches a yarn end of the lower yarn and guides the yarn end to the yarn joining device 16 is arranged below the yarn joining device 16. The lower yarn catching member 19 includes a pipe arm 20b that pivots vertically around an axis 19a, and a lower yarn suction port 19c that is provided at a tip end of the pipe arm 20b. A not-shown negative pressure source is connected to the pipe arm 20b. Because of the negative pressure, a suction current for catching the lower yarn is generated at the lower yarn suction port 19c.
An upper yarn catching member 20 that catches and guides the upper yarn to the yarn joining device 16 is provided above the yarn joining device 16. The upper yarn catching member 20 includes the pipe arm 20b that pivots vertically around an axis 20a, and an upper yarn suction port 20c that is provided at a tip end of the pipe arm 20b. A not-shown negative pressure source is connected to the pipe arm 20b. Because of the negative pressure, a suction current for catching the upper yarn is generated at the upper yarn suction port 20c. The upper yarn catching member 20 functions as a catching portion that catches the yarn 5 having a predetermined length from a yarn end of the yarn 5 wound onto the package 8.
The unit main body 12 further includes a winding device (winding section) 30 that winds the yarn 5 onto the package 8 while traversing the yarn 5. The winding device 30 winds the yarn 5 onto the package 8 while traversing the yarn 5. The winding device 30 includes a cradle 31 and a drum (rotating body) 45.
The cradle 31 holds the package 8 by clamping the winding bobbin 7 of the package 8. The cradle 31 is pivotable between a state in which the held package 8 is in contact with the drum 45 and a state in which the package 8 is separated from the drum 45. When the cradle 31 is holding the winding bobbin 7 on which the yarn 5 is wound, the drum 45 rotates in a state in which the drum 45 is in contact with an outer peripheral surface of the package 8. When the cradle 31 is holding an empty winding bobbin 7 on which the yarn 5 is not wound, the drum 45 rotates in a state in which the drum 45 is in contact with the outer peripheral surface of the winding bobbin 7.
The drum 45 transmits a rotational driving force of a motor 47 to the package 8 that is in contact with the drum 45 so as to rotate the package 8, and traverses the yarn 5 onto a surface of the package 8. A helical traverse groove 45a is formed on the outer peripheral surface of the drum 45. The drum 45 is driven rotatably by the motor 47. The motor 47 is provided on one end of the drum 45 and is housed in a unit frame 10a. Examples of the motor 47 include, for example, a servo motor, a step motor, and the like. The motor 47 is controlled by the unit controller 11.
The yarn 5 unwound from the supply bobbin 6 is wound onto the surface of the package 8 while being traversed at a constant width via the traverse groove 45a formed on the outer peripheral surface of the drum 45. Accordingly, the package 8 having a fixed winding width can be formed. Alternatively, to traverse the yarn 5 in the winding unit 10, the yarn 5 can be caused to move from end to end of the winding bobbin 7 or the package 8. Note that, the term "end" used here does not necessarily mean the "edge" of the winding bobbin 7 or the package 8, and can be borders of a range having a constant width. Furthermore, the term "end to end" used here can mean from one end of the winding bobbin 7 or the package 8 to the other end thereof, or it can mean that the yarn moves from one end of the winding bobbin 7 or the package 8 to the other end thereof and moves back to the one end again. In a configuration in which the yarn 5 is traversed "from one end of the winding bobbin 7 or the package 8 to the other end thereof", it is particularly advantageous to traverse the yarn 5 by using a traverse guide explained later. Alternatively, in a configuration in which "the yarn moves from one end of the winding bobbin 7 or the package 8 to the other end thereof and moves back to the one end again", it is particularly advantageous to traverse the yarn 5 by using the drum 45.
The drum 45 is in contact with the outer peripheral surface of the package 8 when the cradle 31 is holding the winding bobbin 7 onto which the yarn 5 is wound. The drum is in contact with the outer peripheral surface of the winding bobbin 7 when the cradle 31 is holding an empty winding bobbin 7 on which the yarn 5 is not yet wound. In the following explanation, the package 8 and the winding bobbin 7 are collectively referred to as the package 8.
For example, when the package 8 becomes full due to winding of the yarn 5 thereon in the winding unit 10, the doffing device 40 moves to a position of the winding unit 10 and doffs the fully wound package 8 from the winding unit 10, and sets an empty winding bobbin 7 in the winding unit 10. The package 8 doffed by the doffing device 40 is discharged to a not-shown mounting section provided at the rear side of each winding unit 10 (with respect to the automatic winder, a side having a passage for a worker is a front side and an opposite side thereof is a rear side), and is collected by using various means. Note that, the doffing device 40 can appropriately discharge not only the fully wound package 8, but also the package 8 that is not fully wound, or an empty winding bobbin 7. The doffing device 40 needs not be arranged in the automatic winder 1. In such a configuration, it is preferable that the worker performs the doffing manually.
Next, a winding error detecting method that is executed in the automatic winder 1 will be explained.

Stepped Winding Error
First, a method for detecting a winding error called "stepped winding" will be explained in detail. The winding error called stepped winding is an error in which a step of yarn occurs in the package 8 as shown in FIG. 8A. The stepped winding occurs when a traverse length becomes short continuously for some time duration during the winding of the yarn 5. Specifically, such an error can occur when, for example, fly waste etc., accumulates in a part between two plates positioned face to face in a not-shown plate-shaped guide member in a traverse area, and the yarn 5 is not traversed all the way to the end of the package 8.
The unit controller 11 detects an error related to the winding of the yarn 5 (hereinafter, "stepped winding error") based on a running speed of the yarn 5 detected by the yarn monitoring device 17 (error detecting). The unit controller 11 identifies a local maximum value or a local minimum value that fulfills a predetermined condition as a singular point among local maximum values or local minimum values that appear with a change in the running speed over time, or identifies a local maximum value or a local minimum value that fulfills a predetermined condition as a singular point among local maximum values or local minimum values that appear with a change in a speed ratio over time obtained by dividing the running speed by the speed related to the circumferential speed of the package 8, and detects the stepped winding error based on an appearance interval of the singular points.
How the local maximum value and the local minimum value can be identified will be explained below. The storage section stores therein a maximum value and a minimum value of the running speed as initial values. When the running speed of the yarn 5 is acquired by the yarn monitoring device 17, the update section compares the acquired running speed with the maximum value and the minimum value of the running speed stored in the storage section. When the running speed acquired by the yarn monitoring device 17 is higher than the maximum value of the running speed previously stored in the storage section, or when the running speed acquired by the yarn monitoring device 17 is lower than the minimum value of the running speed previously stored in the storage section, the maximum value or the minimum value stored in the storage section is updated with the running speed acquired by the yarn monitoring device 17. The unit controller 11 causes the storage section to store therein yarn positions (first positions) at which the maximum value and the minimum value of the running speed are stored in the storage section. In other words, the storage section stores therein the first position corresponding to the maximum value and the first position corresponding to the minimum value.
Accordingly, the update section updates the maximum value or the minimum value of the running speed stored in the storage section as and when required. Furthermore, the unit controller 11 compares the first position with a yarn position (second position), a position that is different from the first position, at which the running speed is acquired by the yarn monitoring device 17. When a predetermined difference occurs between the first position and the second position, the unit controller 11 identifies the maximum value or the minimum value stored in the storage section as the local maximum value or the local minimum value. In other words, when the maximum value or the minimum value of the running speed stored in the storage section is not updated by a yarn length equivalent to the predetermined difference, the unit controller 11 identifies the maximum value or the minimum value of the running speed stored in the storage section as the local maximum value or the local minimum value. The predetermined difference explained here can be more than or equal to half length of a normal range R explained later, or can be less than or equal to a length obtained by subtracting half length of the normal range R from a reference interval. Furthermore, ideally, by taking the predetermined difference as a value equivalent to half of the reference interval, the local maximum value or the local minimum value that can become noise and the like can be reduced, whereby the local maximum value or the local minimum value can be identified with accuracy. The second position is a position that occurs temporally later than the first position.
Furthermore, it is not necessary to store both the maximum value and the minimum value of the running speed in the storage section, and one between the maximum value and the minimum value of the running speed can be stored in the storage section. Moreover, it is acceptable if the maximum value and the minimum value of the running speed, which are the initial values, are not stored in the storage section. In such a configuration, the running speed acquired for the first time can be stored as the maximum value and the minimum value.
The unit controller 11 includes a setting section that sets the reference interval. A value can be input by the worker in the setting section as the reference interval. Alternatively, an initial value stored beforehand can be set as a reference interval. The set reference interval can be a traverse length or a value equivalent to half the traverse length. The traverse length refers to a distance covered by the yarn when moving from one end of the winding bobbin 7 or the package 8 to the other end thereof and returning to the one end again. The "half the traverse length" refers to a distance covered by the yarn when moving from one end of the winding bobbin 7 or the package 8 to the other end thereof. By setting the reference interval to the traverse length or a value equivalent to half the traverse length, an error can be detected based on a length of the yarn, regardless of the running speed of the yarn. In other words, an error can be detected even when a change in the running speed over time, such as at the start of the yarn winding, is not constant.
Moreover, the reference interval to be set can be set as a time interval. When the reference interval is set as the time interval, an error cannot be detected when a change in the running speed over time, such as the start of the yarn winding, is not constant. However, because, normally, a singular point appears for each period when a change in the running speed over time is constant, an error can be detected. In other words, the process can be simplified by setting the reference interval as the time interval. In the following explanation, the reference interval will be explained as the traverse length. Furthermore, the reference interval and the traverse length, or the value of the half of the traverse length, and the time interval needs not match exactly, and can be values that fall within a range from the exact match.
The unit controller 11 extracts a local maximum value or a local minimum value that appears at the reference interval as the singular point. Specifically, when the reference interval is set equal to the traverse length, the unit controller 11 extracts as the singular point a local maximum value or a local minimum value that occurs in a section in which the running distance from the singular point is largely the same as the traverse length (a predetermined condition). Subsequently, the unit controller 11 detects an error based on the appearance frequency of the extracted singular points. A local maximum value or a local minimum value that occurs outside the reference interval is not determined as an error such as noise or a non-continuous traverse defect. However, when the traverse defect occurs continuously over a certain time duration, it is determined as an error since the package shape becomes stepped.
In the present embodiment, the unit controller 11 identifies a local minimum value, which is to be used as the singular point, from the local minimum values that appears with a change in the speed ratio over time obtained by dividing the running speed by the circumferential speed of the package 8, and detects the stepped winding error based on the appearance interval of the singular point. The unit controller 11 calculates the speed relating to the circumferential of the package 8 based on the circumferential speed of the drum 45 (hereinafter, also referred to as "drum circumferential speed"). The unit controller 11 calculates the drum circumferential speed based on the rotational speed of the drum 45. The unit controller 11 inputs a pulse of a frequency proportional to the rotational speed of the drum 45 (hereinafter, also referred to as a "drum pulse"), and calculates the rotational speed of the drum 45 based on the drum pulse. When the appearance interval changes, the unit controller 11 judges that a stepped winding error has occurred. Alternatively, as another method of calculating the speed relating to the circumferential speed of the package 8, a detecting section that directly detects the rotational speed of the package 8 can be provided and the rotational speed can be calculated based on the detection result.
The unit controller 11 calculates the speed ratio. The unit controller 11 calculates the speed ratio by dividing a running speed of the yarn 5 detected by the yarn monitoring device 17 by the drum circumferential speed.
In FIG. 3A, the horizontal axis indicates time and the vertical axis indicates the running speed of the yarn 5. In FIG. 3A, the running speed is indicated by a solid line, and the drum circumferential speed is indicated by a dashed line. As shown in FIG. 3A, at the time of accelerated winding, the drum circumferential speed increases and the running speed increases while changing in a periodical manner substantially around the drum circumferential speed. In such a case, as the winding of the yarn 5 progresses, a time period of the periodic change in the running speed becomes shorter and the amplitude thereof becomes larger. When the accelerated winding period ends and a previously set winding speed is attained, the speed shifts to a constant winding speed period. At the time of the constant winding speed, the drum circumferential speed remains constant, and the running speed changes in a periodical manner substantially around the drum circumferential speed. At this time, the period and the amplitude are substantially constant.
In FIG. 3B, the horizontal axis indicates time and the vertical axis indicates a speed ratio. As shown in FIG. 3B, the speed ratio changes in a periodical manner substantially around a predetermined value (for example, "1") in the accelerated winding phase and the constant winding speed phase. The amplitude of the speed ratio is substantially constant in the accelerated winding phase and the constant winding speed phase. Accordingly, by performing conversion from the speed data to the speed ratio, a singular point can be identified from the local minimum values that appear with a change over time, regardless of the winding speed.
The unit controller 11 identifies as a singular point a local minimum value that appears with the change in the calculated speed ratio over time. In FIG. 4, the horizontal axis indicates time and the vertical axis indicates a speed ratio. As shown in FIG. 4, local minimum values (portions encircled by dashed lines) appear with the change in the speed ratio over time. The unit controller 11 identifies the local minimum values as the singular points, and detects that a stepped winding error has occurred when the appearance interval of the singular points changes.
The unit controller 11 sets the normal range R of the singular point based on the reference interval set by the setting section. Concretely, the local maximum value or the local minimum value that exists within the normal range R is set as the singular point (predetermined condition). When the local maximum value or the local minimum value does not exist within the normal range R, an estimated point is set within the normal range R. When the number of times the estimated point is set fulfills a predetermined error condition, the unit controller 11 judges that a stepped winding error has occurred.
Specifically, as shown in FIG. 5, the unit controller 11 sets the normal range R of the singular point based on the reference interval set by the setting section. The normal range R is calculated as below. First, a position advanced by a distance equivalent to the reference interval from the previous singular point P1 is obtained. Then, a position obtained by subtracting a winding start threshold value from the calculated position is set as a start position of the normal range R, and a position obtained by adding the winding start threshold value to the calculated position is set as an end position of the normal range R. The winding start threshold value is a value that is appropriately set according to the configuration of the winding unit 10, the properties of the yarn, and the like. In this manner, the unit controller 11 sets a range between the start position and the end position as the normal range R of the winding start state. The normal range R is defined in units of the yarn length or in time units in accordance with the reference interval.
A first singular point is identified as explained below. That is, a normal range is set at a position that exists at a distance advanced by the reference interval from a local maximum value or a local minimum value that appears with the change in the running speed over time, and it is determined whether the local maximum value or the local minimum value exists within the normal range. When the local maximum value or the local minimum value exists within the normal range, the normal range is set at a position that exists at a distance further advanced by the reference interval and is processed in the same manner as explained above. Such a process is repeated several times, and when the local maximum value or the local minimum value exists within the normal range, the value is identified as a singular point, and then the process explained above is performed. When a local maximum value or a local minimum value does not exist within the normal range, a subsequent local maximum value or local minimum value is processed to identify as a singular point by performing the same process.
When the reference interval is taken as the traverse length, a difference in the traverse length occurs between a state in which winding of the yarn 5 onto the package 8 starts (initial traverse length) and a normal state that occurs after the state in which winding starts (average traverse length). The initial traverse length can be a value that is measured by a pilot spindle and output to the unit controller 11 of each winding unit 10. The average traverse length can be updated from the initial traverse length based on the appearance interval of the previous singular points. The update can be performed, for example, by taking an average of the appearance intervals of the previous four singular points. Furthermore, the reference interval can be updated each time by periodically obtaining the average of the appearance intervals. Note that, the number of appearance intervals that is used at the time of updating the reference interval is not limited to four times.
The unit controller 11 sets an estimated point P2 when the identified singular point does not exist within the normal range R. As shown in FIG. 5, the unit controller 11 determines as an error point P3 the local maximum value or the local minimum value that does not exist in the normal range R. In such a case, the unit controller 11 sets the estimated point P2 within the normal range R. The unit controller 11 judges that the stepped winding error has occurred when the number of times the estimated point P2 is set fulfills an error condition. Specifically, when the estimated point P2 is set to a second number (for example, two) in the normal range R that is set to a first number (for example, four) consecutively, the unit controller 11 judges that a stepped winding error has occurred. The second number is a threshold value used to judge that the stepped winding error has occurred. The first number and the second number are arbitrary numbers. Moreover, the first number is larger than the second number. The error point P3 need not necessarily be identified.
As shown in FIG. 6, for example, the unit controller 11 judges "no error" (shown as a circle in the figure) when the estimated point P2 is not set even once during the first number. In such a case, the traverse error rate is "0/4". The unit controller 11 judges "caution" (shown as a triangle in the figure) when the estimated point P2 is set once during the first number. In such a case, the traverse error rate is "1/4". The unit controller 11 judges "error" (shown as a cross in the figure) when the estimated point P2 is set twice during the first number. In such a case, the traverse error rate is "2/4". In a judgment result shown in FIG. 6, a left-pointing arrow indicates that the normal singular point P1 is continuous. When it is judged by the unit controller 11 that an error has occurred, for example, the appearance interval of the singular point becomes short as shown in FIG. 4.
Upon judging that the stepped winding error has occurred, the unit controller 11 calculates a length of a problematic yarn portion based on the estimated point P2. The unit controller 11 calculates the length of the problematic yarn portion based on the traverse error rate. Upon judging that the stepped winding error has occurred, the unit controller 11 calculates a length of the period in which the traverse error rate is greater than zero as the length of the problematic yarn portion. For example, in the example shown in FIG. 6, the unit controller 11 calculates as the length of the problematic yarn portion a length indicated by arrows between a position at which the traverse error rate is judged as "1/4" and a position at which the traverse error rate is judged as "2/4". However, only the position at which the traverse error rate is determined as "2/4" can be judged as the length of the problematic yarn portion. Specifically, the unit controller 11 calculates the length of the problematic yarn portion based on the number of pulses in a period corresponding to the rotation of the drum 45 (number of drum pulses). The unit controller 11 causes the upper yarn catching member 20 to catch the problematic yarn portion. The upper yarn catching member 20 catches only the problematic yarn portion of the length calculated by the unit controller 11.
Upon judging that the stepped winding error has occurred, the unit controller 11 notifies of an error occurrence. Upon judging that the stepped winding error has occurred, the unit controller 11 outputs to the main control device 2 an error signal that indicates the stepped winding error. The main control device 2 displays a notification that indicates the occurrence of the stepped winding error on the display panel 4.

Straight Winding Error
Next, a method for detecting a winding error known as "straight winding" will be explained. The winding error called straight winding is an error in which the yarn 5 is wound onto only on a part of the package 8 as shown in FIG. 8B. The straight winding occurs, for example, when the yarn 5 does not enter the traverse groove 45a of the drum 45 after the yarn joining operation is completed by the yarn joining device 16.
The unit controller 11 detects an error related to the winding of the yarn 5 (hereinafter, "straight winding error") based on a running speed of the yarn 5 detected by the yarn monitoring device 17 (error detecting). The unit controller 11 detects a straight winding error for a predetermined time period after the yarn joining operation is completed by the yarn joining device 16 and the winding of the yarn 5 is started. The predetermined time period is a time taken for the winding speed to reach a prescribed speed, or a time taken for the winding length of the yarn 5 to reach a prescribed length.
The unit controller 11 identifies, as the first singular point and the second singular point, respectively, a local maximum value and a local minimum value that fulfills a predetermined condition among the local maximum values and the local minimum values that appear with the change in the running speed over time, or the local maximum values and the local minimum values that appear with the change in the speed ratio over time obtained by dividing the running speed by a circumferential speed of the drum 45. Subsequently, the straight winding error is detected based on a difference between the first singular point and the second singular point that is nearest to the first singular point. Specifically, the unit controller 11 judges that the straight winding error has occurred when the difference between the first singular point and the second singular point that is nearest to the first singular point is less than or equal to a threshold value. The threshold value is a value that is set appropriately according to the configuration of the winding unit 10, the properties of a yarn, and the like. Furthermore, the method of identifying the local maximum value, the local minimum value, the first singular point, and the second singular point is the same as that used in the explanation of "Stepped Winding Error".
As shown in FIG. 7A, when the yarn 5 is wound normally onto the package 8, the difference between the first singular point and the second singular point is larger than the threshold value. As shown in FIG. 7B, when a straight winding error occurs, the difference between the first singular point and the second singular point is continuously below the threshold value. The unit controller 11 judges that the straight winding error has occurred when the number of times the difference between the first singular point and the second singular point is less than or equal to the threshold value is greater than or equal to a predetermined number. Alternatively, if the difference between the first singular point and the second singular point becomes less than or equal to the threshold value even once, it can be determined that an error has occurred. Moreover, "the second singular point nearest to the corresponding first singular point" can be any second singular point that exists before or after the first singular point (right side and left side shown in FIG. 7A).
The unit controller 11 judges that the straight winding error has occurred when the first singular point and / or the second singular point cannot be identified while a yarn length relating to error determination is being wound. The case in which the first singular point and / or the second singular point cannot be identified is a case in which the running speed stored in the storage section is frequently updated and cannot be identified as a local maximum value and / or a local minimum value. Because the difference between the first singular point and the second singular point cannot be calculated since the first singular point and / or the second singular point cannot be identified, it can be determined that an error has occurred. In another case, if the local maximum value and / or the local minimum value cannot be identified while a yarn length relating to error determination is being wound, it can be similarly judged that a straight winding error has occurred. The "yarn length relating to error determination" here means the yarn of the length equivalent to 1 to 4 traverses.
Upon judging that the straight winding error has occurred, the unit controller 11 calculates the length of the problematic yarn portion. The unit controller 11 calculates the running distance of the yarn 5 from when the yarn joining operation was performed by the yarn joining device 16 up to when it is judged that a straight winding error has occurred, and sets the corresponding running distance as a length of the problematic yarn portion. Specifically, the unit controller 11 calculates the length of the problematic yarn portion based on the number of pulses in a period corresponding to the rotation of the drum 45 (number of drum pulses). The unit controller 11 causes the upper yarn catching member 20 to catch the problematic yarn portion. The upper yarn catching member 20 catches only the problematic yarn portion of the length calculated by the unit controller 11. The reason why the problematic portion of the yarn 5 equivalent to the running distance from when the yarn joining operation is performed by the yarn joining device 16 up to when it is judged that the straight winding error has occurred is caught is because, when it is judged that the straight winding error has occurred, the yarn path does not exist at a normal position thereof after the joining operation by the yarn joining device 16 is completed. Therefore, it becomes necessary to catch the yarn after the joining operation is completed.
Upon judging that the straight winding error has occurred, the unit controller 11 notifies of an error occurrence. Upon judging that the straight winding error has occurred, the unit controller 11 outputs to the main control device 2 an error signal that indicates the straight winding error. The main control device 2 displays a notification that indicates the occurrence of the straight winding error on the display panel 4.
As explained above, in the automatic winder 1 according to the present embodiment, the unit controller 11 can identify a local maximum value or a local minimum value that is necessary for error detection with the change in which the local maximum values or the local minimum values of various sizes appear over time by identifying the local maximum value or the local minimum value, which is to be used as the singular point, from the appeared local maximum values or the local minimum values. Subsequently, the winding error of the yarn 5 (stepped winding error) can be accurately detected based on the appearance interval of the identified singular point.
In the automatic winder 1 according to the present embodiment, the unit controller 11 sets the normal range R. When the identified local maximum value or the local minimum value does not exist within the normal range R, the estimated point P2 is set within the normal range R. When the number of times the estimated point P2 is set fulfills an error condition, it is judged that an error has occurred. In some cases, a singular point may not exist temporarily in the normal range R for some reason other than the winding error of the yarn 5 (such as a defect in signal processing). In such a case, because the winding error of the yarn 5 has not occurred and a defect in which the singular point is does not exist is also temporary, it is not necessary to abnormally stop the winding process of the yarn 5.
The automatic winder 1 according to the present embodiment includes the upper yarn catching member 20 that catches the problematic yarn portion of the yarn 5. The unit controller 11 calculates the length of the problematic yarn portion based on the estimated point P2. The upper yarn catching member 20 catches only the problematic yarn portion of the length calculated by the unit controller 11. In such a configuration, the yarn 5 wound onto the package 8 can be appropriately caught after an error has occurred. Accordingly, the winding of the yarn 5 can be resumed in the automatic winder 1 after an error has occurred.
In the automatic winder 1 according to the present embodiment, the unit controller 11 identifies the first singular point and the second singular point, which are to be used as the singular points, from the local maximum values and the local minimum values that appear with the change in the speed ratio over time, and detects an error based on the difference between the first singular point and the second singular point. With such a configuration, the automatic winder 1 can detect the straight winding error. Accordingly, the winding error of the yarn 5 can be detected accurately in the automatic winder 1.
In the automatic winder 1 according to the present embodiment, the unit controller 11 judges that an error has occurred when the difference between the first singular point and the second singular point is less than or equal to the threshold value. Moreover, when the first singular point and / or the second singular point cannot be detected, the unit controller 11 judges that an error has occurred. With such a configuration, the straight winding error can be detected accurately.
In the automatic winder 1 according to the present embodiment, the drum 45 can include the traverse groove 45a formed on the outer peripheral surface thereof. In a configuration in which the traverse groove 45a is formed on the drum 45, straight winding can occur because the yarn 5 does not enter the traverse groove 45a. Therefore, such a configuration of the automatic winder 1 in which the straight winding error can be detected accurately is particularly effective in a configuration in which the drum 45 includes the traverse grooves 45a formed thereon.
The automatic winder 1 according to the present embodiment includes the yarn joining device 16 that performs a yarn joining operation to make the yarn 5 continuous when the yarn 5 running between the yarn supplying section 18 and the winding device 30 breaks. Upon detecting an error, the unit controller 11 calculates the running distance of the yarn from when the yarn joining operation was performed by the yarn joining device 16 up to when the error is detected. The upper yarn catching member 20 catches the problematic yarn portion of a length equivalent to the running distance. In such a configuration, the yarn 5 wound onto the package 8 can be appropriately caught after an error has occurred. Accordingly, the winding of the yarn 5 can be resumed in the automatic winder 1 after an error has occurred.
The automatic winder 1 according to the present embodiment includes the display panel 4 that notifies of an error occurrence when the error is detected by the unit controller 11. With such a configuration, the worker and the like can be notified that an error has occurred.
The embodiments of the present invention have been explained above. However, the present invention is not necessarily limited to the embodiments explained above, and can be modified in various manners without departing from the gist of the present invention.
In the above embodiments, an embodiment in which the winding bobbin 7 and the package 8 are arranged above the supply bobbin 6 in the machine height direction and the yarn 5 runs from the lower side to the upper side is cited as an example. However, the winding unit 10 can be configured such that the yarn 5 runs from the upper side to the lower side. In such a configuration, it is preferable to read "lower side / below" explained in the present specification as "upper side / above" or "upstream (in the yarn running direction), and "upper side / above" explained in the present specification as "lower side / below" or "downstream (in the yarn running direction).
An embodiment in which the winding device 30 includes the drum 45 is cited above as an example. However, the winding device 30 is not limited to the configuration explained above. For example, the winding device can include a traversing device, and the traversing device can include a traverse guide, a driving motor, a guide plate, and a traverse fulcrum. The traverse guide engages with the yarn 5 that is being wound around the package 8. The driving motor causes the traverse guide to move reciprocally in the package width direction. The traverse guide guides the yarn 5 so as to traverse the yarn 5 that is being wound onto the package 8 while moving reciprocally. The guide plate guides the yarn 5 that is being traversed. The traverse fulcrum engages with the yarn 5 on the upstream side of the guide plate in the running direction of the yarn 5.
An embodiment in which the unit controller 11 functions as an error detecting section that detects an error is cited above as an example. However, the yarn monitoring device 17 itself can function as the error detecting section. In such a configuration, the yarn monitoring device 17 does not output the speed data relating to the running speed of the yarn 5 to the unit controller 11. Moreover, in such a configuration, a drum pulse is input to the yarn monitoring device 17. Accordingly, the yarn monitoring device 17 calculates the length of the problematic yarn section based on the number of drum pulses.
An embodiment in which the yarn monitoring device 17 that includes a function of a speed detecting section that detects the running speed of the yarn 5 and a function to detect a yarn defect is cited above as an example. However, the yarn monitoring device 17 can include a function of the speed detecting section that detects only the running speed of the yarn 5. Alternatively, separate from the yarn monitoring device 17 that detects a yarn defect, the configuration can include a speed detecting device that includes a function of a speed detecting section that detects only the running speed of the yarn 5.
An embodiment in which the unit controller 11 identifies a local minimum value, which is to be used as a singular point, from the local minimum values that appear with the change in the speed ratio over time obtained by dividing the running speed by the circumferential speed of the drum 45 and detects a stepped winding error based on an appearance interval of the singular point is cited above as an example. However, the unit controller 11 can identify a local maximum value, which is to be used as a singular point, from the local maximum values that appear with the change in the running speed over time and detect the stepped winding error based on an appearance interval of the singular point. Alternatively, the unit controller 11 can identify a singular point based on the local maximum value and the local minimum value, and detect an error.
An embodiment in which the unit controller 11 identifies a local minimum value, which is to be used as a singular point, from the local minimum values that appear with the change in the running speed or the speed ratio over time and detects a stepped winding error based on an appearance interval of the singular point is cited as an example. However, the unit controller 11 can identify a local maximum value, which is to be used as a singular point, from the local maximum values that appear with the change in the running speed or the speed ratio over time and detect the stepped winding error based on an appearance interval of the singular point. Alternatively, the unit controller 11 can identify a singular point from the local maximum value and the local minimum value, and detect an error.
An embodiment in which the unit controller 11 identifies a local maximum value and a local minimum value that appear with the change in the speed ratio over time obtained by dividing the running speed by the circumferential speed of the drum 45 and detects a straight winding error based on a difference between the local maximum value and a local minimum value nearest to the corresponding local maximum value is cited above as an example. However, the unit controller 11 can identify the local maximum value and the local minimum value that appear with the change in the running speed over time and detect the straight winding error based on a difference between the local maximum value and the local minimum value nearest to the corresponding local maximum value.
An embodiment in which the unit controller 11 calculates the length of a problematic yarn portion based on the number of pulses in a period that corresponds to the rotation of the drum 45 (number of drum pulses) is cited above as an example. However, the unit controller 11 can calculate the length of the problematic yarn portion based on the running speed of the yarn 5.
An embodiment in which the winding device 30 includes the drum 45 and rotates the package 8 in a state in which the drum 45 is in contact with the outer peripheral surface of the package 8 is cited above as an example. However, the winding device 30 can be configured such that the package 8 is driven directly. In such a case, in a winding device 30 that includes a friction roller that rotates by being in contact with the package 8, the circumferential speed of the package 8 can be calculated based on the rotational speed of the friction roller. Moreover, in a configuration in which the package 8 is driven directly, the circumferential speed of the package 8 can be calculated based on the rotational speed of a driving shaft of the package 8, or the rotational speed of a driving motor of the package 8.
An embodiment in which the yarn monitoring device 17 detects the running speed of the yarn 5 running from the supply bobbin 6 to the winding device 30, and the unit controller 11 detects an error relating to the yarn winding of the yarn 5 based on the running speed detected by the yarn monitoring device 17 is cited above as an example. However, the running speed of the yarn 5 can be obtained based on the tension applied onto the yarn 5. The running speed of the yarn 5 varies when the yarn moves from end to end of the package. Similarly, the tension applied onto the yarn varies when the yarn moves from end to end of the package. In other words, it can be seen that there is a correlation between the change in the running speed and the tension applied onto the yarn. Therefore, by obtaining and storing the relation between the running speed and the tension beforehand, the unit controller 11 can calculate (estimate) the running speed of the yarn 5 based on the tension measurement signal output from the tension detecting device 15. The relation between the running speed and the tension can be stored in a table format, or can be stored in a form of a calculation formula.
An embodiment in which the unit controller 11 detects an error relating to the winding of the yarn 5 based on the running speed detected by the yarn monitoring device 17 is cited above as an example. However, the unit controller 11 can detect an error in the winding of the yarn 5 based on the tension applied onto the yarn 5. The unit controller 11 detects an error relating to the winding of the yarn 5 based on the tension (tension measurement signal) of the yarn 5 detected by the tension detecting device 15.
The unit controller 11 identifies a local maximum value or a local minimum value, which is to be used as a singular point, from the local maximum values or the local minimum values that appear with a change in the tension over time, and detects a stepped winding error based on the appearance interval of the singular point. In such a configuration, by identifying the local maximum value or the local minimum value, which is to be used as the singular point, from the appeared local maximum values or the local minimum values, the local maximum value or the local minimum value necessary for error detection can be identified with the change in which the local maximum values or the local minimum values of various sizes appear over time. Consequently, an error in the winding of the yarn 5 can be detected accurately based on an appearance frequency of the identified singular point. Moreover, even in the case of the tension, an error can be detected based on the difference between a first singular point and a second singular point. Furthermore, a method to obtain the local maximum value and the local minimum value of the tension and a method to specify the singular point are obtained by performing the same processing as that performed for obtaining the running speed.
As a means to identify the local maximum value and the local minimum value, a method in which the maximum value and the minimum value of the running speed are stored in the storage section and the local maximum value and the local minimum value are identified based on a position of the yarn at which the maximum value and the minimum value of the running speed are stored and a position of the yarn at which the running speed is newly acquired is explained. However, for example, the running speed of several traverses can be stored and the local maximum value and the local minimum value can be identified based on the stored running speeds. In such a configuration, the local maximum value and the local minimum value can be identified by comparing the running speed acquired at the time at which local maximum value and local minimum value are obtained and the running speed acquired near that time.
As a means to detect an error, a method in which an error is detected based on the reference interval is explained. However, an error can be detected based on the change in the appearance interval of the singular point. For example, an error can be detected when a difference of a predetermined value or more occurs between the new appearance interval and the immediately previous appearance interval.
As a means to detect an error, a method in which an estimated point is set in the normal range R is explained. However, it is acceptable when the estimated point is not necessarily set, and an error can be detected, for example, by performing the same processing as that of the estimated point based on the number of times the local maximum value or the local minimum value do not exist in the normal range R.
According to one aspect of the present invention, a yarn winding machine includes a yarn supplying section capable of supplying a yarn; a winding section that traverses and winds the yarn supplied from the yarn supplying section to form a package; a speed acquiring section that acquires a running speed of the yarn running from the yarn supplying section toward the winding section; and an error detecting section that detects an error relating to winding of the yarn based on the running speed acquired by the speed acquiring section. The error detecting section identifies, as a singular point, at least one between a local maximum value and a local minimum value that fulfills a predetermined condition among one between local maximum values or local minimum values that appear with a change in the running speed over time; local maximum values or local minimum values that appear with a change in a speed ratio over time obtained by dividing the running speed by a speed relating to a circumferential speed of the package, and detects an error based on an appearance interval at which the singular point appears.
In the yarn winding machine according to the one aspect of the present invention, the singular point is identified from the appeared local maximum value or the local minimum value. Accordingly, the local maximum values or the local minimum values necessary for detecting an error can be identified with the change in which local maximum values or local minimum values of various sizes appear over time. Subsequently, an error in the yarn winding can be detected accurately based on an appearance interval of the identified singular point.
The above yarn winding machine can include a setting section that sets a reference interval. Considering that one between a local maximum value and a local minimum value that appears in the reference interval fulfills a predetermined condition, the error detecting section can identify the one between the local maximum value and the local minimum value as the singular point. With such a configuration, the local maximum values or the local minimum values that are not necessary for judging an error can be excluded based on the reference interval, and an error can be accurately detected based only on the local maximum value or the local minimum value necessary for the error judgment.
In the above yarn winding machine, the reference interval can be defined based on a predetermined yarn length that is wound by the winding section when the yarn is moved from end to end of the package by the winding section by traversing the yarn, and the predetermined yarn length can be a constant length regardless of the running speed. With such a configuration, a singular point can be identified based on the length of the yarn, regardless of the running speed.
In the above yarn winding machine, the setting section can set a normal range for a point advanced by the reference interval from a predetermined singular point. Moreover, considering that one between a local maximum value and a local minimum value that exists within the normal range fulfills a predetermined condition, the error detecting section can identify the one between the local maximum value and the local minimum value as the singular value. Because the singular point can be identified for each reference interval while the normal winding is being performed, the singular point can be identified accurately.
In the above yarn winding machine, the error detecting section can judge that the error has occurred when, in the normal range set continuously for a first number, number of times the local maximum value or the local minimum value does not appear within the normal range fulfills an error condition in which a second number is exceeded. In some cases, a singular point may not exist temporarily within the normal range due to reasons other than a yarn winding error (such as a signal processing defect). In such a case, the yarn winding error does not occur, and a defect in which the singular point does not exist is also temporary. Therefore, the yarn winding process need not be stopped abnormally. With such a configuration, abnormal stopping of the yarn winding process can be prevented even when the local maximum value or the local minimum value does not exist temporarily within the normal range. Accordingly, unnecessary abnormal stopping of the yarn winding process can be prevented as long as it does not affect the package quality.
In the above yarn winding machine, the error detecting section can set an estimated point within the normal range when the local maximum value or the local minimum value does not exist within the normal range, and can judge that an error has occurred when, in the normal range set continuously for the first number, number of times the estimated point is set fulfills an error condition in which the second number is exceeded. In some cases, the singular point may not exist temporarily within the normal range due to reasons other than a yarn winding error (such as the signal processing defect). In such a case, the yarn winding error does not occur, and the defect in which the local maximum value or the local minimum value does not exist is temporary. Therefore, the yarn winding process need not be stopped abnormally. In such a configuration, even if the local maximum value or the local minimum value does not exist temporarily within the normal range, the abnormal stopping of the yarn winding process can be prevented by setting the estimated point. Accordingly, unnecessary abnormal stopping of the yarn winding process can be prevented as long as it does not affect the package quality.
The above yarn winding machine can include a catching section that catches a problematic portion of the yarn that forms the package. The error detecting section can calculate a length of the problematic portion based on the estimated point, and the catching section can catch from the package only the problematic portion of the length calculated by the error detecting section. With such a configuration, the yarn wound onto the package can be appropriately caught after an error has occurred. Accordingly, yarn winding can be resumed in the yarn winding machine after an error has occurred.
In the above yarn winding machine, the setting section can update the reference interval based on the past appearance interval. With such a configuration, because the reference interval can be updated as required, the reference interval can be optimized.
The above yarn winding machine can include a storage section that stores therein one between a maximum value and a minimum value of the running speed, and an update section that compares, when the maximum value is stored in the storage section, the running speed that is newly acquired by the speed acquiring section and the maximum value stored in the storage section and updates the maximum value stored in the storage section with a new maximum value when the new running speed is larger than the stored maximum value, or compares, when the minimum value is stored in the storage section, the running speed that is newly acquired by the speed acquiring section and the minimum value stored in the storage section, and updates the minimum value stored in the storage section with a new minimum value when the newly acquired running speed is larger than the stored minimum value. The error detecting section can identify the maximum value or the minimum value stored in the storage section as a local maximum value or a local minimum value when a predetermined difference occurs between a first position of the yarn at the time at which the new running speed is acquired by the speed acquiring section and a second position of the yarn at the time at which the maximum value or the minimum value is updated by the update section. With such a configuration, the maximum value or the minimum value in a predetermined range of the yarn length can be set as the local maximum value or the local minimum value, instead of setting all the points that change with the increase and decrease of the running speed as the local maximum value or the local minimum value. Consequently, the number of stored local maximum values or the local minimum values can be reduced, and the number of local maximum values or the local minimum values to be considered while identifying the singular point can be reduced.
In the above yarn winding machine, the error detecting section can judge that the error has occurred when the appearance interval changes. With such a configuration, a winding error in the stepped winding can be detected accurately.
According to another aspect of the present invention, a yarn winding machine includes a yarn supplying section capable of supplying a yarn; a winding section that traverses and winds the yarn supplied from the yarn supplying section to form a package; a speed acquiring section that acquires a running speed of the yarn running from the yarn supplying section toward the winding section; and an error detecting section that detects an error relating to winding of the yarn based on the running speed of the yarn acquired by the speed acquiring section. The error detecting section identifies, as a first singular point and a second singular point, respectively, a local maximum value and a local minimum value that fulfill a predetermined condition among one between local maximum values and local minimum values that appear with a change in the running speed over time; local maximum values and local minimum values that appear with a change in a speed ratio over time obtained by dividing the running speed acquired by the speed acquiring section by a speed relating to a circumferential speed of the package, and detects an error based on a difference between the first singular point and the second singular point nearest to the corresponding first singular point.
The inventor of the present invention found that when a winding error called "straight winding" occurs in a package, there is no change in the speed of the yarn during winding. Based on these findings, the inventor of the present invention found that there is a relation between a difference between a specific local maximum value and a specific local minimum value that appear with the change in the running speed or the speed ratio over time of the yarn, and the occurrence of yarn winding error (straight winding). Accordingly, in the yarn winding machine according to the another aspect of the present invention, the error detecting section identifies the first singular point and the second singular point from the local maximum values and the local minimum values that appear with a change in the running speed or the speed ratio over time, and detects an error based on the difference between the first singular point and the second singular point. Accordingly, in the above yarn winding machine, an error in the straight winding can be detected. Consequently, a yarn winding error can be detected accurately in the above yarn winding machine.
The above yarn winding machine can include a setting section that sets a reference interval. Considering that a local maximum value and a local minimum value that appear in the reference interval fulfill the predetermined condition, the error detecting section can identify the local maximum value and the local minimum value as the first singular point and the second singular point, respectively. With such a configuration, the local maximum values or the local minimum values that are not necessary for the error judgment are excluded, and the error can be detected accurately based only on the local maximum value and the local minimum value necessary for the error judgment.
In the above yarn winding machine, the reference interval can be defined based on a predetermined yarn length that is wound by the winding section when the winding section moves the yarn from end to end of a package by traversing the yarn and the predetermined yarn length can be a constant length regardless of the running speed. With such a configuration, a singular point can be identified based on the length of the yarn, regardless of the running speed.
In the above yarn winding machine, the setting section can set a normal range for a point offset from a predetermined singular point by the reference interval. Moreover, considering that a local maximum value and a local minimum value that exist within the normal range fulfill the predetermined condition, the error detecting section can identify the local maximum value and the local minimum value as the first singular point and the second singular point, respectively. Because the first singular point and the second singular point can be identified for each reference interval when the normal winding is being performed, the first singular point and the second singular point can be identified accurately.
The above yarn winding machine can include a storage section that stores therein a maximum value and a minimum value of a running speed, and an update section that compares a new running speed acquired by the speed acquiring section with the maximum value and the minimum value stored in the storage section and updates the maximum value or the minimum value stored in the storage section as a new maximum value or a new minimum value when the new running speed is larger than the maximum value or smaller than the minimum value. The error detecting section can identify the maximum value or the minimum value stored in the storage section as a local maximum value or a local minimum value, when a predetermined difference occurs between a first position of the yarn at the time at which a new running speed is acquired by the speed acquiring section and a second position of the yarn at the time at which a maximum value or a minimum value is updated by the update section. With such a configuration, the maximum value or the minimum value in a predetermined range of the yarn length can be set as the local maximum value or the local minimum value, instead of setting all the points that change with the increase and decrease of the running speed as the local maximum value or the local minimum value. Consequently, the number of stored local maximum values or the local minimum values can be reduced, and the number of local maximum values or the local minimum values that are considered when identifying the first and second singular points can be reduced.
In the above yarn winding machine, the error detecting section can judge that an error has occurred when a difference between the first singular point and the second singular point nearest to the corresponding first singular point is less than or equal to a threshold value. With such a configuration, the straight winding error can be detected accurately.
In the above yarn winding machine, the error detecting section can judge that an error has occurred when at least one between the first singular point and the second singular point cannot be identified while a yarn length relating to error determination is being wound. With such a configuration, the straight winding error can be detected accurately.
In the above yarn winding machine, the error detecting section can judge that an error has occurred when at least one between the local maximum value and the local minimum value cannot be identified while a yarn length relating to error determination is being wound. With such a configuration, the straight winding error can be detected accurately.
The above yarn winding machine can include a yarn joining device that performs a yarn joining operation to make the yarn continuous when the yarn splits between the yarn supplying section and the winding section; and a catching section that catches a problematic portion of the yarn that forms the package. Upon detecting that the error has occurred, the error detecting section can calculate a running distance of the yarn from when yarn joining operation is performed in the yarn joining device up to when the error is detected, and the catching section can catch the problematic portion of the yarn of the length equivalent to the running distance from the package. With such a configuration, the yarn wound onto the package can be caught appropriately after an error has occurred. Accordingly, yarn winding can be resumed in the yarn winding machine after an error has occurred.
The above yarn winding machine can include a tension detecting section that detects tension applied onto the yarn running from the yarn supplying section toward the winding section. The speed acquiring section can acquire the running speed of the yarn based on the tension of the yarn detected by the tension detecting section.
According to still another aspect of the present invention, a yarn winding machine includes a yarn supplying section capable of supplying a yarn; a winding section that traverses and winds the yarn supplied from the yarn supplying section to form a package; a tension detecting section that detects tension of the yarn running from the yarn supplying section toward the winding section; and an error detecting section that detects an error relating to winding of the yarn based on the tension of the yarn detected by the tension detecting section. The error detecting section identifies, as a singular point, one between a local maximum value and a local minimum value that fulfills a predetermined condition among local maximum values and local minimum values that appear in a change in the tension over time, and detects an error based on an appearance interval of the singular point.
In the yarn winding machine according to the still another aspect of the present invention, the singular point is identified from the appeared local maximum value or the local minimum value. Accordingly, the local maximum values or the local minimum values necessary for detecting an error can be identified with the change in which local maximum values or local minimum values of various sizes appear over time. Subsequently, an error in the yarn winding can be detected accurately based on an appearance interval of the identified singular point.
According to still another aspect of the present invention, a yarn winding machine includes a yarn supplying section capable of supplying a yarn; a winding section that traverses and winds the yarn supplied from the yarn supplying section to form a package; a tension detecting section that detects tension of the yarn running from the yarn supplying section toward the winding section; and an error detecting section that detects an error relating to winding of the yarn based on the tension of the yarn detected by the tension detecting section. The error detecting section identifies, as a first singular point and a second singular point, respectively, a local maximum value and a local minimum value that fulfill a predetermined condition among local maximum values and local minimum values that appear in a change in the tension over time, and detects an error based on a difference between the first singular point and the second singular point nearest to the corresponding first singular point.
The inventor of the present invention found that there is no change in the tension of the yarn during winding when a winding error called "straight winding" occurs in the package. Based on these findings, the inventor of the present invention found that there is a relation between the difference between a specific local maximum value and a specific local minimum value that appear with a change in the yarn tension over time, and the occurrence of yarn winding error (straight winding). Accordingly, the error detecting section in the above yarn winding machine identifies the first singular point and the second singular point from the local maximum values and the local minimum values that appear with a change in the yarn tension over time, and detects an error based on the difference between the first singular point and the second singular point. Accordingly, in the above yarn winding machine, an error in the straight winding can be detected. Consequently, a yarn winding error can be detected accurately in the above yarn winding machine.
According to still another aspect of the present invention, a winding error detecting method executed by a yarn winding machine that includes a yarn supplying section capable of supplying a yarn and a winding section that traverses and winds the yarn supplied from the yarn supplying section to form a package, includes speed acquiring in which a running speed of the yarn running from the yarn supplying section toward the winding section is acquired; and error detecting in which an error relating to winding of the yarn is detected based on the running speed acquired via the speed acquiring. The error detecting includes identifying, as a singular point, one between a local maximum value and a local minimum value that fulfills a predetermined condition among one between local maximum values or local minimum values that appear with a change in the running speed over time; local maximum values or local minimum values that appear with a change in a speed ratio over time obtained by dividing the running speed by a speed relating to a circumferential speed of the package, and detecting an error based on an appearance interval of the singular point.
In the winding error detecting method according to the still another aspect of the present invention, the singular point is identified from the appeared local maximum value or the local minimum value. Accordingly, the local maximum values or the local minimum values necessary for detecting an error can be identified with a change in which local maximum values or local minimum values of various sizes appear over time. Subsequently, an error in the yarn winding can be detected accurately based on an appearance interval of the identified singular point.
According to still another aspect of the present invention, a winding error detecting method executed by a yarn winding machine that includes a yarn supplying section capable of supplying a yarn and a winding section that traverses and winds the yarn supplied from the yarn supplying section to form a package, includes speed acquiring in which a running speed of the yarn running from the yarn supplying section toward the winding section is acquired; and error detecting in which an error relating to winding of the yarn is detected based on the running speed acquired in the speed acquiring. The error detecting includes identifying, as a first singular point and a second singular point, respectively, a local maximum value and a local minimum value that fulfill a predetermined condition among one between local maximum values and local minimum values that appear with a change in the running speed over time; local maximum values and local minimum values that appear with a change in a speed ratio over time obtained by dividing the running speed by a speed relating to a circumferential speed of the package, and detecting an error based on a difference between the first singular point and the second singular point nearest to the corresponding first singular point.
The inventor of the present invention found that when a winding error called "straight winding" occurs in a package, there is no change in the speed of the yarn during winding. Based on these findings, the inventor of the present invention found that there is a relation between a difference between a specific local maximum value and a specific local minimum value that appear with a change in the running speed or the speed ratio over time of the yarn, and the occurrence of yarn winding error (straight winding). Accordingly, in the error detecting section in the winding error detecting method according to the still another aspect of the present invention, the first singular point and the second singular point are identified from the local maximum values and the local minimum values that appear with the change in the running speed or the speed ratio over time, and an error is detected based on the difference between the first singular point and the second singular point. Accordingly, an error in the straight winding can be detected by using the above winding error detecting method. Therefore, the winding error of the yarn can be detected accurately by using the above winding error detecting method.
According to the still another aspect of the present invention, the winding error of the yarn can be detected accurately.
In the above explanation, the meaning of "a plurality of" also includes "a predetermined number of".
Although the invention has been explained with respect to specific embodiments for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the scope of the claims.