BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The present invention relates to a synchronous control method for a loom including
a shedding device that includes a shedding motor independent from a main shaft motor
of the loom as a driving source and that displaces each of healds in an up-down direction
as a single drive shaft common to all of the healds is driven by the shedding motor,
and relates to the loom.
2. Description of the Related Art
[0002] A Jacquard shedding device is well known as a shedding device that causes warp yarns
to perform shedding motion.
[0003] The Jacquard shedding device is configured to displace each of healds independently
upward or downward in accordance with a preset pattern in order to cause warp yarns
passed through the healds to enter a shed state as a single drive shaft that is common
to all of the healds is rotated.
[0004] Regarding a loom including such a Jacquard shedding device, in general, each time
the main shaft of the loom is rotated one turn, the drive shaft of the shedding device
is rotated 1/2 turn. As a structure for rotating the drive shaft in this way, to date,
there are the following two types: a mechanical structure in which the main shaft
is used as a driving source; and an electrical structure in which a dedicated motor
is used as a driving source.
[0005] With the former mechanical structure, the loom is configured so that the drive shaft
of the shedding device and the main shaft of the loom are mechanically coupled to
each other by using a shaft, a chain, and the like. However, this structure has a
problem in that a large number of mechanical components are necessary and maintenance
is very troublesome.
[0006] On the other hand, with the latter electrical structure, the loom is configured so
that the drive shaft of the shedding device is driven by a dedicated driving motor
(shedding motor) that is independent from the main shaft motor of the loom. With this
structure, coupling between the drive shaft of the shedding device and the main shaft
of the loom is electrical. Therefore, this structure has advantages in that the number
of mechanical components can be reduced and ease of maintenance is improved, compared
with the mechanical structure. Japanese Unexamined Patent Application Publication
No.
3-249233 discloses a loom in which such an electrical structure is used to couple the drive
shaft of the Jacquard shedding device and the main shaft of the loom to each other.
SUMMARY OF THE INVENTION
[0007] The loom described in Japanese Unexamined Patent Application Publication No.
3-249233 synchronously controls driving of the shedding motor so that the rotation of the
drive shaft of the shedding device is synchronized with the rotation of the main shaft
of the loom.
[0008] In a shedding device, because healds, through which warp yarns keeping a predetermined
tension are passed, are displaced up or down, a load that is applied to the drive
shaft is large. In addition, in general, a Jacquard shedding device is used to weave
a fabric having a complicated woven design. Therefore, in the Jacquard shedding device,
the healds are driven in accordance with a complicated pattern, and accordingly, there
are many cases where the number of healds that are displaced upward and the number
of healds that are displaced downward considerably vary from loom cycle to loom cycle.
In this case, a load that is applied to the drive shaft considerably varies from loom
cycle to loom cycle.
[0009] Therefore, in order to synchronously control driving of the shedding motor as described
above, it is necessary to control driving of the shedding motor so that the rotation
of the drive shaft is not delayed or advanced by being affected by the load variation.
[0010] Moreover, the main shaft of the loom is coupled to a beating device, and a load generated
by the beating motion (swinging of a reed) is applied to the main shaft of the loom.
Therefore, the rotation of the main shaft is not uniform and varies during one turn
(in one loom cycle). Accordingly, it is necessary to perform the synchronous control
of the shedding motor so that the rotation of the drive shaft follows the rotation
of the main shaft that varies in this way.
[0011] Therefore, in a Jacquard shedding device that uses a dedicated driving motor (shedding
motor) as a driving source, in general, a high-power synchronous motor (for example,
a servomotor), which enables such synchronous control, is used as the shedding motor.
However, because such a synchronous motor is expensive, the cost of a loom including
the Jacquard shedding device is increased.
[0012] The present invention has been made in consideration of the above circumstances,
and an object the present invention is to provide a synchronous control method for
a loom with which it is not necessary to use such a high power synchronous motor as
a shedding motor in the loom described above and that enables the total cost of the
loom to be kept down, and to provide the loom.
[0013] The present invention is based on a loom including a shedding device that includes
a shedding motor independent from a main shaft motor of the loom as a driving source
and that displaces each of healds in an up-down direction as a single drive shaft
that is common to all of the healds is driven by the shedding motor.
[0014] A synchronous control method for a loom according to the present invention includes
detecting a rotation amount of the drive shaft in each weaving cycle at least when
the loom is performing a normal operation, and controlling driving of the main shaft
motor so that a main shaft of the loom is rotated so as to be synchronized with the
drive shaft in accordance with a detection signal indicating the detected rotation
amount.
[0015] In the synchronous control method for a loom according to the present invention,
the controlling of driving of the main shaft motor may include rotating the main shaft
by a target rotation amount, the target rotation amount being obtained based on the
rotation amount of the drive shaft that is detected at each set period that is preset,
in the set period from a time when the target rotation amount is obtained; detecting
an actual rotation angle of the main shaft at a time when a rotation angle of the
main shaft is expected to reach a set angle that is a preset and predetermined rotation
angle of the main shaft; obtaining a deviation of the actual rotation angle from the
set angle by comparing the detected actual rotation angle with the set angle; and
correcting, at a time when the deviation for a preset number of times is obtained,
the target rotation amount that is obtained for the set period after the time, based
on the deviation.
[0016] In the synchronous control method for a loom according to the present invention,
a control parameter that is used to control the main shaft motor may be changed in
accordance with a load that is applied to the drive shaft as the healds are displaced.
[0017] A loom for realizing a synchronous control method according to the present invention
is based on a loom including a shedding device and a main shaft control device, the
shedding device including a shedding motor independent from a main shaft motor of
the loom as a driving source and displacing each of healds in an up-down direction
as a single drive shaft that is common to all of the healds is driven by the shedding
motor, the main shaft control device controlling driving of the main shaft motor.
[0018] In the present invention, the loom includes a rotation detecting device that detects
a rotation amount of the drive shaft in each weaving cycle at least when the loom
is performing a normal operation; and a synchronous control device that obtains a
rotation amount of a main shaft of the loom so that the main shaft is synchronized
with the drive shaft in accordance with a detection signal that is output from the
rotation detecting device, the synchronous control device outputting a rotation command
signal based on the obtained rotation amount of the main shaft to the main shaft control
device.
[0019] In the loom according to the present invention, the synchronous control device may
include a calculating unit that obtains a target rotation amount based on a rotation
amount of the drive shaft that is detected at each set period that is preset, the
target rotation amount being a rotation amount by which the main shaft is to be rotated
in the set period from a time when the target rotation amount is obtained; an angle
detector that obtains an actual rotation angle of the main shaft at a time when a
rotation angle of the main shaft is expected to reach a set angle that is a preset
and predetermined rotation angle of the main shaft; and a comparing unit that obtains
a deviation of the actual rotation angle obtained by the angle detector from the set
angle by comparing the actual rotation angle with the set angle; and the calculating
unit may include a correcting unit that corrects, at a time when the deviation for
a preset number of times is obtained, the target rotation amount that is obtained
for the set period after the time, based on the deviation.
[0020] In the loom according to the present invention, the synchronous control device may
have a function of changing a control parameter that is used to control the main shaft
motor in accordance with a load that is applied to the drive shaft as the healds are
displaced.
[0021] With the present invention, because synchronous control of the drive shaft and the
main shaft is performed so that the rotation of the main shaft of the loom is synchronized
with the rotation of the drive shaft of the shedding device, it is not necessary that
the shedding motor have an ability of maintaining the synchronous state of the drive
shaft, in which a large load is applied to the main shaft during weaving as described
above. Thus, an inexpensive induction motor, instead of an expensive synchronous motor,
can be used as the shedding motor, and accordingly the cost of the shedding device
can be reduced.
[0022] Because the rotation of the main shaft is made to synchronize with the rotation of
the drive shaft, it is necessary to use a synchronous motor as the main shaft motor,
and accordingly the cost of the main shaft motor increases. However, when a load that
is applied to the drive shaft (a load due to displacing of the healds) and a load
that is applied to the main shaft (a load due to swinging of the reed) are compared
with each other, the load that is applied to the main shaft is about a half of the
load that is applied to the drive shaft and is sufficiently small. Therefore, even
in a case where a synchronous motor is used as the main shaft motor, the main shaft
motor may be an inexpensive motor whose power is lower than that of the shedding motor
of existing looms. Accordingly, although the cost of the main shaft motor itself is
increased to some extent, the cost of the entirety of the loom can be reduced compared
with a case where a synchronous motor is used as the shedding motor.
[0023] In the present invention, by controlling driving of the main shaft motor so that
the target rotation amount of the main shaft is corrected, even in a case where a
mismatch between the rotation amounts of the drive shaft and the main shaft occurs,
the mismatch is eliminated and a state in which the rotation of the main shaft is
more accurately synchronized with the rotation of the drive shaft can be maintained.
[0024] To be specific, in the present invention, although the rotation of the main shaft
is synchronized with the rotation of the drive shaft, a mismatch between the rotation
amounts of the drive shaft and the main shaft may occur for some reason (for example,
abnormal vibration of the loom).
[0025] Therefore, an actual rotation angle of the main shaft at a time when the rotation
angle of the main shaft is expected to reach the set angle is detected, and the mismatch
(deviation) between the rotation amounts is obtained by comparing the detected actual
rotation angle with the set angle. In addition, by controlling driving of the main
shaft motor so as to correct the target rotation amount of the main shaft based on
the obtained deviation, the mismatch can be eliminated. As a result, it is possible
to maintain a state in which the main shaft is more accurately synchronized with the
drive shaft.
[0026] In the present invention, by changing a control parameter that is used to control
the main shaft motor in accordance with a load that is applied to the drive shaft,
a load on the main shaft motor can be suppressed.
[0027] To be specific, the load that is applied to the drive shaft varies from loom cycle
to loom cycle as described above, and accordingly the rotation of the drive shaft
varies from loom cycle to loom cycle. In the present invention, because the rotation
of the main shaft is made to follow the rotation of the drive shaft that varies, the
load on the main shaft motor is large when the variation is large.
[0028] Therefore, by changing the control parameter so as to reduce the followability of
the rotation of the main shaft to the rotation of the drive shaft in a weaving cycle
in which the load that is applied to the drive shaft is large, the load on the main
shaft motor can be suppressed in a case where variation in the rotation of the drive
shaft is large.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029]
Fig. 1 is a block diagram illustrating an example of the structure of a loom according
to the present invention;
Fig. 2 is a block diagram illustrating an example of the structure of a synchronous
control device; and
Fig. 3 is a block diagram illustrating another example of the structure of a synchronous
control device.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0030] Fig. 1 illustrates an example of a loom to which the present invention is applied.
A loom according to the present embodiment is composed of a weaving device 1 that
includes a loom body 11 including a weft insertion device, a beating device, and the
like (not shown); and a Jacquard shedding device 2 that includes a Jacquard body 21,
which is disposed above the weaving device 1 (the loom body 11), as a shedding device
that causes warp yarns to perform shedding motion. The Jacquard shedding device 2
uses a dedicated motor (a shedding motor 23) that is independent from a motor of the
loom body 11 (a main shaft motor 13) as a driving source. The Jacquard body 21 is
mechanically independent from the loom body 11.
[0031] The weaving device 1 further includes, in addition to the loom body 11, which includes
a main shaft 12 and which performs weaving by using the aforementioned weft insertion
device, the beating device, and the like, the main shaft motor 13 for rotating the
main shaft 12 of the loom body 11, and a main shaft control device 14 for controlling
the rotation of the main shaft motor 13. The weaving device 1 includes a main-shaft-side
encoder 15 for detecting the rotation amount of the main shaft 12 that is rotated
as described above, and an input setting device 16 for inputting and setting set values
of weaving conditions and the like.
[0032] The main shaft motor 13 is coupled to the main shaft 12 of the loom body 11 via a
drive transmission mechanism 17 such as a speed reducer. In the present embodiment,
the main shaft motor 13 is a synchronous motor. Examples of the synchronous motor
include an IPM motor. The main shaft 12 is rotated by the main shaft motor 13. In
addition, the beating device, which is included in the aforementioned loom body 11,
is configured so that a reed that is coupled to the main shaft 12 is swung due to
the rotation of the main shaft 12. Accordingly, in the beating device, as the main
shaft 12 is rotated as described above, the reed is swung and beating motion is performed.
[0033] Moreover, in the weaving device 1, weaving is performed as the aforementioned weft
insertion device performs weft insertion. Devices related to weaving, such as the
weft insertion device, are controlled in accordance with a rotation angle of the main
shaft 12 (hereafter, referred to as "crank angle") that is detected. Therefore, the
weaving device 1 includes the main-shaft-side encoder 15 for detecting the crank angle.
The main-shaft-side encoder 15 outputs a detection signal corresponding to the detected
crank angle (hereafter, referred to as "main-shaft-side detection signal Rm") to a
device controller (not shown) for controlling the operation of each device.
[0034] The main-shaft-side detection signal Rm is output also to the main shaft control
device 14 that controls driving of the main shaft motor 13. In addition, the main
shaft control device 14 is configured to control driving of the main shaft motor 13
based on a rotation command signal Rc (described below) that is input and the main-shaft-side
detection signal Rm from the main-shaft-side encoder 15.
[0035] The input setting device 16 is a device for inputting and setting set values of weaving
conditions for the weaving operation. The weaving conditions include a set rotation
speed that is a rotation speed (rotation speed in a normal operation) of the loom
that is assumed (set) for a weaving operation at the time, a warp shedding pattern
in which the (upper, lower) positions of the warp yarns for each weaving cycle are
set, and the like. The input setting device 16 includes, for example, a touch panel
display device. The input setting device 16 allows an operator to input and set the
aforementioned set values by using a setting screen displayed on the display device.
The input setting device 16 is connected to the loom body 11, and is configured to
transmit the set values, which have been input and set, to corresponding device controllers
in the loom body 11.
[0036] The Jacquard shedding device 2 includes a plurality of healds (not shown) that correspond
in number to the warp yarns and through each of which a corresponding one of the warp
yarns is inserted, the Jacquard body 21 that forms a warp shed by displacing the healds
in the up-down direction, the shedding motor 23 that is a driving source of the Jacquard
body 21, and a shedding control device 24 that controls the rotation of the shedding
motor 23. The Jacquard shedding device 2 further includes a shedding-side encoder
25, which is a rotation amount detection device that detects the rotation amount of
a drive shaft 22 of the Jacquard body 21 rotated by the shedding motor 23.
[0037] The Jacquard body 21 includes the single drive shaft 22, and is configured to displace
the healds in the up-down direction as the drive shaft 22 is rotated. That is, the
single drive shaft 22 of the Jacquard body 21 is common to all of the healds. The
drive shaft 22 is coupled to the shedding motor 23 via a drive transmission mechanism
26 such as a speed reducer. In the present embodiment, the shedding motor 23 is an
induction motor. Because the structure of the Jacquard body 21 itself is well known,
detailed descriptions thereof will be omitted. The Jacquard body 21 includes a driving
mechanism (not shown) that includes a structure for converting the rotation of the
drive shaft 22 into motion in the up-down direction. The driving mechanism is coupled
to each of the healds via a rope (wire) that is provided so as to correspond to the
heald and that is connected to the heald. The driving mechanism is configured so that
the healds are displaced in the up-down direction in accordance with the rotation
of the drive shaft 22.
[0038] The shedding control device 24 is connected to the input setting device 16 of the
weaving device 1 and is connected also to the shedding-side encoder 25. In addition,
to the shedding control device 24, a set rotation speed and a shedding pattern, which
are included in the aforementioned weaving conditions, are transmitted from the input
setting device 16. A detection signal corresponding to the rotation amount of the
drive shaft 22 that is detected by the shedding-side encoder 25 (hereafter, referred
to as "shedding-side detection signal Rd") is output from the shedding-side encoder
25 to the shedding control device 24. In the present embodiment, the driving mechanism
is configured to cause each heald to perform weaving motions for two weaving cycles
when the drive shaft 22 is rotated one turn. Accordingly, in the present embodiment,
the drive shaft 22 is rotated 1/2 turn in one loom cycle. Therefore, the shedding
control device 24 is configured to control driving of the shedding motor 23 based
on a set rotation speed and the shedding-side detection signal Rd so that the drive
shaft 22 is driven with a rotation speed that is 1/2 of the set rotation speed. The
shedding control device 24 is configured to control the Jacquard body 21 (driving
mechanism) so that the healds are displaced in accordance with the shedding pattern.
[0039] In the loom including the weaving device 1 and the Jacquard shedding device 2 described
above, according to the present invention, the loom includes a synchronous control
device 3 that obtains the rotation amount of the main shaft 12 so that the main shaft
12 of the loom body 11 of the weaving device 1 is rotated so as to be synchronized
with the drive shaft 22 of the Jacquard body 21 of the Jacquard shedding device 2
in accordance with the shedding-side detection signal Rd of a rotation detecting device
(the shedding-side encoder 25) in a normal operation. The synchronous control device
3 outputs the rotation command signal Rc based on the obtained rotation amount of
the main shaft 12 to the main shaft control device 14.
[0040] As illustrated in Fig. 1, the synchronous control device 3 is connected to the shedding-side
encoder 25 and the main-shaft-side encoder 15 at input ends thereof, and is connected
to the main shaft control device 14 at an output end thereof. As illustrated in Fig.
2, the synchronous control device 3 includes components such as a calculating unit
31, a determination unit 32, an angle detector 33, and a comparing unit 34. Specifics
of these components are as follows.
[0041] As illustrated in Fig. 2, the calculating unit 31 includes a rotation amount calculating
unit 35 and a correcting unit 36. Among these, the rotation amount calculating unit
35 is connected to the shedding-side encoder 25 and the correcting unit 36 at input
ends thereof, and is connected to the main shaft control device 14 at an output end
thereof. The correcting unit 36 is connected to the comparing unit 34 at an input
end thereof, and is connected to the rotation amount calculating unit 35 at an output
end thereof.
[0042] The rotation amount calculating unit 35 is configured to obtain, at each preset period
(for example, 0.5 msec, hereafter, referred to as "set period"), a rotation amount
of the drive shaft 22 (hereafter, referred to as "drive shaft rotation amount") in
the set period based on the shedding-side detection signal Rd output from the shedding-side
encoder 25 during the set period. Moreover, the rotation amount calculating unit 35
is configured, each time the drive shaft rotation amount is obtained in this way (at
each set period), to obtain, from the obtained drive shaft rotation amount, a target
rotation amount that is a rotation amount by which the main shaft 12 is to be rotated
in a period until the shedding-side detection signal Rd is next input (during the
set period).
[0043] The target rotation amount, which is a rotation amount for causing of the rotation
of the main shaft 12 to follow the rotation of the drive shaft 22, is a rotation amount
with which the rotation angle of the main shaft 12 reaches, at a time 0.5 msec (the
set period) after the drive shaft rotation amount is next obtained, a rotation angle
corresponding to the rotation angle of the drive shaft 22 at a time when a drive shaft
rotation used to obtain the target rotation amount was obtained. The rotation angle
corresponding to the rotation angle of the drive shaft 22 is twice the rotation angle
of the drive shaft 22. Accordingly, the target rotation amount can be obtained by
multiplying the drive shaft rotation amount by 2.
[0044] To be specific, on the weaving device 1 side, usually, one weaving operation (an
operation for weaving, including one weft insertion, beating, and the like) is performed
as the main shaft 12 is rotated one turn. In weaving using a loom, the one weaving
operation is repeatedly performed, and the one weaving operation corresponds to one
cycle of the loom ("one loom cycle" (also referred to as "one weaving cycle")). As
described above, the Jacquard shedding device 2 according to the present embodiment
is configured so that each heald performs motions for two weaving cycles each time
the drive shaft 22 rotates one turn. In other words, with the Jacquard shedding device
2, a motion for one weaving cycle is performed with 1/2 turn of the drive shaft 22.
Accordingly, the main shaft 12 should be driven so that the main shaft 12 rotates
one turn while the drive shaft 22 rotates 1/2 turn, and therefore the target rotation
amount is twice the drive shaft rotation amount.
[0045] In addition, the rotation amount calculating unit 35 is configured to generate, based
on the obtained target rotation amount, the rotation command signal Rc that is used
by the aforementioned main shaft control device 14 to control the main shaft motor
13 and that enables the main shaft 12 to be rotated with the target rotation amount;
and to output the rotation command signal Rc to the main shaft control device 14.
[0046] The synchronous control device 3 according to the present embodiment is configured
to correct the rotation amount of the main shaft 12 based on a deviation between the
shedding-side detection signal Rd and the main-shaft-side detection signal Rm.
[0047] To be specific, because the rotation amount calculating unit 35 is configured as
described above and the main shaft control device 14 drives the main shaft motor 13
in accordance with the rotation command signal Rc, it is expected that the main shaft
12 is rotated so as to follow the rotation of the drive shaft 22 with a delay of the
set period (0.5 msec) during one turn thereof (in one weaving cycle). Accordingly,
if the time when the rotation angle of the main shaft 12 reaches a preset and predetermined
rotation angle in one rotation of the main shaft 12 ("set angle" in the present invention,
hereafter referred to as "set angle") is compared with the time when the drive shaft
22 reached a rotation angle of the drive shaft 22 corresponding to the set angle (hereafter,
referred to as "reference angle"), it is expected that the time when the main shaft
12 reaches the set angle is the set period (0.5 msec) after the time when the drive
shaft 22 reached the reference angle. However, as the case may be, for some reason
(for example, abnormal vibration of the loom), a mismatch between the rotation amounts
of the drive shaft 22 and the main shaft 12 may occur, and the time when the main
shaft 12 reaches the set angle may become advanced or delayed by more than 0.5 msec
relative to the time when the drive shaft 22 reached the reference angle.
[0048] Therefore, the synchronous control device 3 according to the present embodiment is
configured to correct the rotation amount of the main shaft 12 based on the shedding-side
detection signal Rd of the shedding-side encoder 25 and the main-shaft-side detection
signal Rm of the main-shaft-side encoder 15. The synchronous control device 3 includes,
as components for performing the correction, the determination unit 32, the angle
detector 33, the comparing unit 34, and the correcting unit 36 included in the calculating
unit 31.
[0049] In the present embodiment, 0° (360°) is set as the set angle of the main shaft 12,
and 180° and 360° (0°) are each set as the reference angle of the drive shaft 22 corresponding
to the set angle.
[0050] The determination unit 32 is connected to the shedding-side encoder 25 at an input
end thereof, and is connected to the angle detector 33 at an output end thereof. The
determination unit 32 is configured to obtain the rotation angle of the drive shaft
22 based on the shedding-side detection signal Rd output from the shedding-side encoder
25. In addition, the determination unit 32 is configured to determine whether the
obtained rotation angle of the drive shaft 22 has reached the reference angle (180°,
360° (0°)) and, to output, 0.5 msec (the set period) after the time when it is determined
that the rotation angle has reached the reference angle, a signal that indicates a
timing at which the crank angle is to reach the set angle (0°) (hereafter, referred
to as "reference signal T0") to the angle detector 33.
[0051] The angle detector 33 is connected to the main-shaft-side encoder 15 and the determination
unit 32 at input ends thereof, and is connected to the comparing unit 34 at an output
end thereof. The angle detector 33 is configured to be capable of obtaining the crank
angle based on the main-shaft-side detection signal Rm output from the main-shaft-side
encoder 15. In addition, the angle detector 33 is configured to obtain the crank angle
at the time when the reference signal T0 is output from the determination unit 32.
Moreover, the angle detector 33 is configured to output a signal that indicates the
obtained crank angle (hereafter, referred to as "angle signal θ") to the comparing
unit 34.
[0052] The comparing unit 34 is connected to the angle detector 33 at an input end thereof,
and is connected to the correcting unit 36 of the calculating unit 31 at an output
end thereof. The comparing unit 34 is configured, when the angle signal θ is output
from the angle detector 33, to obtain a deviation of the crank angle from the set
angle by comparing the crank angle indicated by the angle signal θ with the set angle
(0°), that is, a rotation angle that the crank angle is expected to reach at the time
when the reference signal T0 is output, and to output a deviation signal Δθ that indicates
the obtained deviation to the calculating unit 31. Here, "deviation" includes 0. That
is, if the deviation is 0, the comparing unit 34 outputs the deviation signal Δθ corresponding
to deviation = 0 to the calculating unit 31. The deviation is obtained so as to have
a positive value if the rotation of the main shaft 12 is delayed relative to the rotation
of the drive shaft 22 and a negative value if the rotation of the drive shaft 22 is
advanced relative to the rotation of the drive shaft 22.
[0053] The correcting unit 36 of the calculating unit 31 is connected to the comparing unit
34 at an input end thereof, and is connected to the rotation amount calculating unit
35 at an output end thereof. The correcting unit 36 is configured, when the deviation
signal Δθ is input from the comparing unit 34, based on the deviation that is indicated
by the deviation signal Δθ, to obtain a correction rotation amount for correcting
the target rotation amount of the main shaft 12 obtained by the rotation amount calculating
unit 35 as described above.
[0054] To be specific, the correcting unit 36 is configured to store a deviation that is
indicated by the deviation signal Δθ each time the deviation signal Δθ is input from
the comparing unit 34 and to calculate, when the number of times the deviation signal
Δθ has been input reaches a preset number of times (for example, 10 times (10 weaving
cycles), hereafter referred to as "set number of times"), the average value of the
deviations for the set number of times (hereafter, referred to as "deviation average
value"). Note that the time when the deviation signal Δθ is output from the comparing
unit 34 is a time when the set period (0.5 msec) has elapsed from the time when the
drive shaft 22 reached the reference angle, and is a time when the drive shaft rotation
amount at this time is obtained by the correcting unit 36 (that is, the time when
the target rotation amount of the main shaft 12 is obtained based on the drive shaft
rotation amount and when the rotation command signal Rc is generated and output).
[0055] The correcting unit 36 is configured to obtain a correction rotation amount based
on a deviation average value each time the deviation average value is obtained as
described above. To be specific, in the present embodiment, in the correcting unit
36, a plurality of correction rotation amounts corresponding to a plurality of expected
deviations have been set beforehand so as to each correspond to a magnitude of deviation,
and the correcting unit 36 selects a correction rotation amount corresponding to the
magnitude of the deviation average value obtained as described above. Regarding the
correction rotation amount, in a case where the deviation average value > 0, because
this a state in which the rotation of the main shaft 12 is delayed relative to the
rotation of the drive shaft 22, a rotation amount that increases the value of the
target rotation amount, that is, a rotation amount such that the correction rotation
amount > 0 is set. In a case where the deviation average value < 0, because this is
a state in which the rotation of the main shaft 12 is advanced relative to the rotation
of the drive shaft 22, a rotation amount that decreases the value of target rotation
amount, that is, a rotation amount such that the correction rotation amount < 0 is
set. In a case where the deviation average value = 0, a rotation amount that does
not increase or decrease the value of the target rotation amount, that is, the correction
rotation amount = 0 is set. In addition, the correcting unit 36 is configured to output,
to the rotation amount calculating unit 35, the correction signal C corresponding
to the correction rotation amount obtained in this way each time the correction rotation
amount is obtained (each time the deviation average value is calculated).
[0056] The rotation amount calculating unit 35 is configured, when the correction signal
C is output from the correcting unit 36, to correct the target rotation amount of
the main shaft 12 obtained at the time, based on a correction rotation amount indicated
by the correction signal C. That is, the rotation amount calculating unit 35 is configured,
when the deviation average value is obtained as described above at a time when the
correction rotation amount is obtained by the correcting unit 36, that is, at a time
when the deviation signal Δθ at the set number of times is output from the comparing
unit 34, outputs the rotation command signal Rc to be output at the time as a signal
corresponding to a rotation amount that is obtained by adding a correction rotation
amount corresponding to the deviation average value to the target rotation amount.
[0057] Accordingly, in a case where the deviation average value > 0, that is, in a case
where the rotation of the main shaft 12 is delayed relative to the rotation of the
drive shaft 22, because the correction rotation amount > 0, the rotation amount calculating
unit 35 outputs the rotation command signal Rc corresponding to a new target rotation
amount in which the value of the target rotation amount (a rotation amount that is
twice the drive shaft rotation amount) is increased. In a case where the deviation
average value < 0, that is, in a case where the rotation of the main shaft 12 is advanced
relative to the rotation of the drive shaft 22, because the correction rotation amount
< 0, the rotation amount calculating unit 35 outputs the rotation command signal Rc
corresponding to a new target rotation amount in which the value of the target rotation
amount is reduced. Moreover, in a case where the deviation average value = 0, that
is, in a case where there is no mismatch between the rotation amounts of the drive
shaft 22 and the main shaft 12, because the correction rotation amount = 0, the rotation
amount calculating unit 35 outputs the rotation command signal Rc corresponding to
the target rotation amount.
[0058] In the present embodiment, the synchronous control device 3 may be a device such
that the components thereof each include a circuit that is composed of circuit elements
having respective functions, or a computer that is programmed so as to have the functions
of the components may operate as the synchronous control device 3. The synchronous
control device 3, the main shaft control device 14, the shedding control device 24,
and the input setting device 16 may be independent devices (including computers that
operate as the devices); or one computer may operate as a plurality of devices.
[0059] The operational effects of a loom including the synchronous control device 3 according
to the present embodiment are as described below in (1) to (8).
- (1) When an operation button (not shown) is pressed to start the operation of the
loom, the shedding control device 24 of the Jacquard shedding device 2 starts driving
the shedding motor 23. Accordingly, rotation of the drive shaft 22 is started. The
shedding motor 23 is driven so that the drive shaft 22 is rotated at a rotation speed
that is 1/2 of a set rotation speed that is preset as a weaving condition.
- (2) When the rotation of the drive shaft 22 is started, the shedding-side encoder
25 detects the rotation amount, and accordingly the shedding-side detection signal
Rd corresponding to the rotation amount is output from the shedding-side encoder 25
to the synchronous control device 3.
- (3) In addition, in the synchronous control device 3, at each set period (0.5 msec)
from the time when the rotation of the drive shaft 22 is started as described above,
based on the shedding-side detection signal Rd from the shedding-side encoder 25,
the rotation amount calculating unit 35 of the calculating unit 31 obtains the drive
shaft rotation amount in the preceding set period.
- (4) Moreover, in the calculating unit 31 (the rotation amount calculating unit 35)
of the synchronous control device 3, each time the drive shaft rotation amount is
obtained in this way (that is, at each set period), the target rotation amount of
the main shaft 12 is obtained as described above based on the obtained drive shaft
rotation amount. When the target rotation amount of the main shaft 12 is obtained
in this way, the rotation command signal Rc corresponding to the target rotation amount
is output from the rotation amount calculating unit 35 to the main shaft control device
14 of the weaving device 1.
- (5) As the rotation command signal Rc is output, the main shaft control device 14
controls driving of the main shaft motor 13 so that the main shaft 12 rotates by the
target rotation amount indicated by the rotation command signal Rc in the set period
from the time. As a result, in the loom, the main shaft 12 is rotated so as to follow
the rotation of the drive shaft 22 with a delay of the set period (0.5 msec). That
is, the loom enters a state in which the main shaft 12 is rotated so as to be synchronized
with the rotation of the drive shaft 22.
- (6) Thus, with the loom described above, because the drive shaft 22 of the Jacquard
shedding device 2 is rotated based on the set rotation speed and the main shaft 12
of the weaving device 1 is rotated so as to be synchronized with (follow) the rotation
of the drive shaft 22, compared with existing looms in which the drive shaft 22 is
rotated so as to be synchronized with the rotation of the main shaft 12, an inexpensive
induction motor, instead of an expensive synchronous motor used in existing looms,
can be used as the shedding motor 23. Also regarding the main shaft motor 13, an inexpensive
synchronous motor may be used in consideration of a load that is applied to the main
shaft 12. Therefore, the cost of the entirety of the loom can be reduced.
- (7) As described above, driving of the main shaft motor 13 is controlled so that the
main shaft 12 is rotated so as to be synchronized with the rotation of the drive shaft
22. In addition, in the loom according to the present embodiment, control for correcting
the target rotation amount of the main shaft 12 is performed at a predetermined time,
as necessary, so that a state in which the rotation of the main shaft 12 is more accurately
synchronized with the rotation of the drive shaft 22 is maintained. Specifics are
as follows.
In the loom according to the present embodiment, at a time when the crank angle is
expected to reach the set angle (360° (0°)), that is, at a time when the set period
(0.5 msec) has elapsed from the time when the rotation angle of the drive shaft 22
reached the reference angle, in the synchronous control device 3, the reference signal
TO is output from the determination unit 32 to the angle detector 33.
Accordingly, the angle detector 33 obtains a crank angle (actual crank angle) at the
time based on the main-shaft-side detection signal Rm output from the main-shaft-side
encoder 15, and the angle signal θ corresponding to the actual crank angle is output
to the comparing unit 34.
In the comparing unit 34, the obtained actual crank angle is compared with the set
angle (0°) that the crank angle is expected to reach at the time when the reference
signal T0 is output, thereby obtaining the deviation. The comparing unit 34 outputs
the deviation signal Δθ corresponding to the obtained deviation to the correcting
unit 36 of the calculating unit 31.
In the correcting unit 36, the deviation average value is obtained from the deviation
signals Δθ for the set number of times as described above, and the correction signal
C corresponding to a correction rotation amount obtained based on the deviation average
value is output to the rotation amount calculating unit 35 of the calculating unit
31.
In the rotation amount calculating unit 35, the target rotation amount of the main
shaft 12 is corrected based on the correction rotation amount. The correction is made
to the target rotation amount of the main shaft 12 obtained at a time when the deviation
average value is calculated (at a time when the deviation signal Δθ at the set number
of times is output from the comparing unit 34). The rotation command signal Rc corresponding
to the corrected target rotation amount of the main shaft 12 is output from the rotation
amount calculating unit 35 to the main shaft control device 14, and the main shaft
motor 13 is driven by the main shaft control device 14 based on the corrected target
rotation amount of the main shaft 12.
- (8) Accordingly, even in a case where a mismatch between the rotation amounts of the
drive shaft 22 and the main shaft 12 occurs for some reason as described above, with
the loom according to the present embodiment, because the synchronous control device
3 performs correction control to correct the rotation amount of the main shaft 12
at a predetermined time so as to eliminate the mismatch, it is possible to maintain
a state in which the rotation of the main shaft 12 is more accurately synchronized
with the rotation of the drive shaft 22.
[0060] The present invention is not limited to the embodiment described above (the above
embodiment) and may be carried out in any of modified embodiments (1) to (9) described
below.
- (1) In the above embodiment, on the assumption that weaving is performed so that a
state of the Jacquard shedding device in which the rotation angle of the drive shaft
is 0° (360°) or 180° corresponds to a state of the weaving device (loom body) in which
the crank angle is 0°, driving of the main shaft is controlled based on the drive
shaft rotation amount.
The above assumption is based on a configuration such that the Jacquard shedding device
drives the healds so that the healds enter a closed state when the rotation angle
of the drive shaft = 0° (360°) or 180° and so that weaving is performed under weaving
conditions under which the warp yarns are in a closed state at a beating time when
the crank angle = 0°. However, weaving using a loom (not limited to the loom according
to the present invention) is not necessarily performed so that the crank angle = 0°,
which is a crank angle at the time of beating (beating angle), coincides with a cross
timing at which the warp yarns enter a closed state. Depending on the weaving conditions,
weaving may be performed so that the cross timing is set at a time before the crank
angle becomes 0°, for example, at a time when the crank angle becomes 300°.
The present invention is applicable, concerning the relationship between the beating
angle and the cross timing, not only to the case where weaving is performed so that
the beating angle coincides with the cross timing as in the above embodiment but also
to a case where weaving is performed so that the beating angle and the cross timing
differ from each other. To be specific, in a case where the Jacquard shedding device
is configured so that the warp yarns enter a closed state when the rotation angle
of the drive shaft is 0° (360°) or 180° as described above and where weaving is performed
so that the Jacquard shedding device causes the warp yarns to enter a closed state
when, for example, the crank angle in the loom body is 300°, driving of the main shaft
is controlled so that the crank angle reaches 300° at a time when a preset period
(in the above embodiment, 0.5 msec) has elapsed after the time when the rotation angle
of the drive shaft reached 0° (360°) or 180°.
- (2) In the above embodiment, regarding the set angle determined in one rotation of
the main shaft, a rotation angle based on an actual crank angle obtained from the
reference angle of the drive shaft corresponding to the set angle is compared with
the set angle, and correction of the target rotation amount of the main shaft is performed
based on a deviation (deviation average value) that is obtained as a result of the
comparison. In addition, in the above embodiment, the set angle is 0°.
However, in the present invention, the set angle is not limited to 0°, and may be
a rotation angle other than 0°. However, if correction of the target rotation amount
of the main shaft is performed during a weft insertion operation, weft insertion may
be influenced. Therefore, preferably, the set angle is a rotation angle at which a
weft insertion operation is not performed (a rotation angle in a period from the time
when a weft insertion operation finishes to a time when the next weft insertion operation
starts).
In a case where the set angle is a rotation angle other than 0°, naturally, the reference
angle of the drive shaft is an angle corresponding to the set angle other than 0°.
To be specific, in a case where the set angle is 20°, in a loom that performs weaving
so that the cross timing and the beating angle coincide with each other as in the
above embodiment, the reference angle is 10° (20°/2) and 190° (20°/2 + 180°).
In a loom that performs weaving so that the cross timing and the beating angle differ
from each other (with an angle difference between the cross timing and the beating
angle) as in the example describe above, the reference angle is an angle corresponding
to the angle difference. To be specific, for example, in a loom in which the crank
angle corresponding to the rotation angle 0° of the drive shaft is set at 300°, because
the rotation of the drive shaft is advanced by 30° (corresponding to a crank angle
of 60°) relative to the rotation of the main shaft, in a case where the set angle
is 20°, the reference angle is 40° (10° + 30°) and 220° (190° + 30°).
- (3) In the above embodiment, correction of the target rotation amount of the main
shaft (hereafter, simply referred to as "correction") is performed at a time when
the deviation at the set number of times, which is preset, is obtained as described
above. In addition, in the above embodiment, the set number of times is 10 times.
However, in the present invention, the set number of times is not limited to 10 times,
and may be another number of times (for example, 30 times). A set number of times
in the present invention is not limited to a plurality of times as described above
and may be a single time. In this case, each time the deviation is obtained, that
is, each time the main shaft rotates one turn, the correction is performed. Moreover,
even in a case where the set number of times is set at a plurality of times, the correction
need not be performed based on the deviation average value as in the above embodiment,
and the correction may be performed based on a (single) deviation obtained at the
set number of times.
- (4) In the above embodiment, regarding calculation of the deviation average value,
the deviation is obtained each time the main shaft rotates one turn, and, at a time
when the deviation at the set number of times is obtained, the deviation average value
is calculated based on the deviations for the set number of times.
However, in the present invention, instead of using such a calculation method, the
deviation average value may be obtained from the average value of actual crank angles
for the set number of times and the set value of the set angle. In this case, the
angle detector of the synchronous control device may have a function of obtaining
the average value. To be specific, the angle detector may be configured to store an
actual crank angle that is obtained each time the main shaft rotates one turn, obtain
the average value of the stored actual crank angles for the set number of times at
the set number of times, and output the average value to the comparing unit. In addition,
the comparing unit may calculate the deviation (deviation average value) based on
the average value of the actual crank angles output from the angle detector and the
set value of the set angle.
- (5) In the above embodiment, control related to the correction is performed so that
the correction is finished through three processes: a process (first process) of obtaining
a deviation based on the set angle and the actual crank angle; a process (second process)
of obtaining a correction rotation amount based on the deviation; and a process (third
process) of correcting the target rotation amount by using the obtained correction
rotation amount. In addition, in the above embodiment, the three processes are performed
continuously (at the same time, concerning control). To be specific, at a time when
the reference signal is output, that is, at a time when the crank angle is expected
to reach the set angle (at a time when the set period has elapsed from the time when
the rotation angle of the drive shaft reached the reference angle), the first process,
the second process, and the third process are performed (although the three processes
are successively performed, because the time required to perform the three processes
is sufficiently shorter than the set period, it can be regarded that the three processes
are performed at the same time.).
However, in the present invention, the three processes need not be performed at the
same time and may be performed at different times. For example, the first process
and the second process may be performed at the time when the reference signal is output,
and the third process may be performed at a time when n set periods (n ≥ 1) have elapsed
after the time when the reference signal is output. Because the target rotation amount
is obtained each time the set period elapses as described above, the target rotation
amount to be corrected is a target rotation amount that is obtained at a time when
the third process is performed. Alternatively, in the above case, instead of performing
the first process and the second process at the same time, the second process and
the third process may be performed at the same time.
- (6) In the above embodiment, the correction is performed by using the correction rotation
amount corresponding to the obtained deviation (deviation average value).
However, in the present invention, the correction rotation amount in the correction
is not limited a value corresponding to a deviation that is obtained as in the above
embodiment, and may be a fixed value (fixed rotation amount) that is preset. In this
case, as a result of the comparing unit obtaining the deviation (deviation average
value), whether the deviation is a positive deviation or a negative deviation is determined,
and accordingly a deviation signal corresponding to the sign of the deviation is output
from the comparing unit to the calculating unit (correcting unit). The correction
is performed so as to add or subtract, in accordance with the sign of the deviation
that is indicated by the deviation signal, a correction rotation amount that has a
positive fixed value that is preset with respect to the target rotation amount. To
be specific, if the deviation signal output from the comparing unit indicates a positive
deviation, that is, if the rotation of the main shaft is delayed relative to the rotation
of the drive shaft, the correction is performed so as to add a fixed rotation amount
to the target rotation amount. If the deviation signal output from the comparing unit
indicates a negative deviation, that is, if the rotation of the main shaft is advanced
relative to the rotation of the drive shaft, the correction is performed so as to
subtract a fixed rotation amount from the target rotation amount.
- (7) In the example described above, the synchronous control device is configured so
that a mismatch (deviation) between the rotation amounts of the main shaft and the
drive shaft is eliminated by the correction, that is, the synchronous control device
is configured to have such a correction function.
However, in the present invention, the synchronous control device is not limited to
a device that is configured to have such a correction function. The synchronous control
device may be configured to output an alarm signal to the loom body in response to
occurrence of the deviation. In this case, if a slight mismatch between the rotation
amounts is allowed, the synchronous control device may be configured to output the
alarm signal when the deviation exceeds a preset allowance. In addition, the loom
body may be configured, when the alarm signal is output from the synchronous control
device, to output a message indicating that, for example, a synchronization mismatch
has occurred between the shedding device and the weaving device on a display device,
such as the input setting device in the above embodiment. Moreover, the loom body
may be configured to perform, in response to outputting of the alarm signal, a stopping
operation in addition to (or instead of) displaying of the message.
- (8) As described above, in the present invention, driving of the main shaft motor
is controlled so that the main shaft follows the rotation of the drive shaft.
In general, a Jacquard shedding device is used to weave a fabric having a complicated
woven design. The shedding pattern is set for one repeat that is composed of a plurality
of weaving cycles, and weaving is performed as healds are repeatedly driven in accordance
with the shedding pattern. Moreover, when weaving a fabric having the complicated
woven design, the shedding pattern may be set so that the number of warp yarns that
are located at upper positions in each weaving cycle in one repeat of the shedding
pattern and the number of warp yarns that are located at lower positions in the weaving
cycle considerably differ from each other.
In the Jacquard shedding device, each heald is mechanically urged in one of upward
and downward directions (generally, downward), and is displaced in the other direction
by the Jacquard body (driving mechanism). Accordingly, a load is applied to the drive
shaft when displacing the healds as described above, and the magnitude of the load
is proportional to the number of healds that are displaced in the other direction.
With the present invention, an inexpensive induction motor can be used as the shedding
motor as described above. In this case, however, depending on the magnitude of the
load that is applied to the drive shaft, the rotation of the drive shaft may be influenced
by the load.
Regarding the influence of the load on the rotation of the drive shaft, naturally,
the influence increases as the load increases, and variation in the rotation speed
may occur depending on the magnitude of the load. However, although the magnitude
of the load is proportional to the number of healds that are displaced in the other
direction as described above, the number of healds that are displaced in the other
direction is determined by the relationship between the vertical positions of the
warp yarns at the time of the largest shed in each weaving cycle, which are set in
the shedding pattern, and the vertical positions of the warp yarns at the time of
the largest shed in the next weaving cycle subsequent to the weaving cycle. Warp yarns
that are set at positions in the other direction at the time of the largest shed in
each weaving cycle and that are to be set at positions in the other direction at the
time of the largest shed in the next weaving cycle start to be displaced toward the
positions in the other direction at about the middle of the next weaving cycle.
Accordingly, in the case where the shedding pattern is set so that the number of warp
yarns that are located at upper positions in each weaving cycle and the number of
warp yarns that are located at lower positions in the weaving cycle considerably differ
from each other as described above, in one or more specific weaving cycles in one
repeat of the shedding pattern, a situation in which the rotation speed of the drive
shaft varies at about the middle of the weaving cycle occurs. In this case, if driving
of the main shaft is controlled so that the rotation of the main shaft follows the
rotation of the drive shaft as described above, because the drive control is performed
so as to sharply change the rotation speed of the main shaft at about the middle of
the weaving cycle, the load that is applied to the main shaft motor becomes large.
It is possible to predict whether such variation in the rotation speed occurs at about
the middle of the weaving cycle from the shedding pattern in consideration of the
weaving condition at the time. If it is expected beforehand that such variation in
the rotation speed will occur, a control parameter that is used to control driving
of the main shaft motor in the main shaft control device may be changed (for example,
the control gain may be reduced). By doing so, it is possible to suppress variation
in the rotation of the main shaft motor by reducing the followability of the main
shaft motor, and accordingly a load that is applied to the main shaft motor can be
suppressed.
In this case, however, because the followability of the main shaft motor is reduced
even in a weaving cycle in which variation in the rotation speed of the drive shaft
does not occur, a mismatch between the drive shaft and the main shaft may occur, and
weft insertion may be influenced in the weaving cycle.
Therefore, in the present invention, the synchronous control device may be configured
to change a control parameter that is used to control the main shaft motor in accordance
with the magnitude of a load that is applied to the drive shaft. To be specific, the
synchronous control device may be configured to change the control parameter in each
weaving cycle in one repeat of the shedding pattern based on the shedding pattern.
As a component for performing this, the synchronous control device includes a parameter
changer. Hereafter, the structure of the parameter changer will be described in detail
with reference to Fig. 3. In Fig. 3, components that are the same as those of the
above embodiment are denoted by the same numerals.
First, it is assumed that the main shaft control device 14 is configured to change
a control parameter that is used to control driving of the main shaft motor 13 in
accordance with an output from the synchronous control device 3. Here, the control
parameter is a control gain. The control gain is a control parameter for changing
the followability of the main shaft motor 13, and it is possible to reduce the followability
of the main shaft motor 13 by reducing the value of the control gain.
In general, a shedding pattern stored in the shedding control device 24 is set so
as to include weaving steps (one weaving step = one weaving cycle) in one repeat of
the shedding pattern. Therefore, it is assumed that the shedding control device 24
is configured to recognize the present weaving step based on the shedding-side detection
signal Rd from the shedding-side encoder 25 and to output a step signal S indicating
the step number at a time when the weaving step is updated.
As illustrated in Fig. 3, the synchronous control device 3 includes a parameter changer
37 in addition to the components of the above embodiment. The parameter changer 37
is connected to the shedding control device 24 and the input setting device 16 of
the weaving device 1 at input ends thereof, and is connected to the main shaft control
device 14 at an output end thereof. In addition, in the parameter changer 37, control
gains having a plurality of values are preset (stored) so as to correspond to the
weaving cycles in one repeat of the shedding pattern (weaving steps).
Regarding the control gains, to be specific, first, a reference control gain, which
is a control gain that is considered to be appropriate for control in a case where
variation in the rotation speed of the drive shaft 22 (and further variation in the
rotation speed of the main shaft motor 13 that is controlled to be driven so that
the main shaft 12 follows the rotation of the drive shaft 22) does not occur, is set.
In addition, for each of weaving steps (weaving cycles) in which variation in the
rotation speed of the drive shaft 22 is expected to occur based on the shedding pattern,
a control gain that is lower than the reference control gain is set so as to correspond
to the step number. On the other hand, for each of the other weaving steps, the reference
control gain is set so as to correspond to the step number. The control gains are
input and set by the input setting device 16. The control gains, which have been input
and set, are transmitted to the parameter changer 37 and stored in the parameter changer
37.
The parameter changer 37 is configured, when the step signal S is output from the
shedding control device 24, to select a value of the control gain corresponding to
the step number indicated by the step signal S and to output a gain signal G indicating
the value to the main shaft control device 14.
In the main shaft control device 14, when the gain signal G is output from the parameter
changer 37, based on the gain signal G, the value of the control gain used to control
driving of the main shaft 12 is changed to a value corresponding to the control gain
indicated by the gain signal G.
With the synchronous control device 3 configured as described above, driving of the
main shaft motor 13 is controlled in each weaving cycle in one repeat of the shedding
pattern by using a control gain that corresponds to the weaving cycle (weaving step)
and that is set as described above. Thus, in a weaving cycle in which a load that
is applied to the drive shaft 22 is large, variation in the rotation of the main shaft
motor 13 is suppressed in order to reduce the followability of the main shaft motor
13, and accordingly a load on the main shaft motor 13 is reduced. In a weaving cycle
in which a load that is applied to the drive shaft 22 is small, the followability
of the main shaft motor 13 is not reduced, and therefore occurrence of a synchronization
mismatch between the drive shaft 22 and the main shaft 12 can be prevented.
In the above description, the control parameter is a control gain. However, the control
parameter is not limited to a control gain and may be another control parameter, such
as a time constant that is related to the responsiveness of the main shaft motor 13.
In the above description, the control parameter is changed by using a method of selecting
a control gain from control gains having a plurality of values that have been set
beforehand. However, a method for changing the control parameter is not limited to
such a method. For example, the control parameter may be changed by using a method
such as calculating the control gain based on the magnitude of a load that is applied
to the drive shaft 22. In this case, the magnitude of a load that is applied to the
drive shaft 22 may be calculated based on the shedding pattern (to be specific, the
number of healds that are displaced in each weaving cycle).
- (9) Heretofore, examples in which the present invention is applied to a loom that
includes a Jacquard shedding device as a shedding device have been described. However,
regarding a loom to which the present invention is applied, the shedding device is
not limited to the Jacquard shedding device. The shedding device may be a dobby shedding
device that uses a so-called rotary driving method in which a heald frame is displaced
in the up-down direction by using a single drive shaft and in which the drive shaft
is rotated by a shedding motor that is independent from the main shaft motor of the
loom. That is, the present invention is applicable also to a loom that includes such
a dobby shedding device.
[0061] The present invention is not limited to the embodiments described above and may be
appropriately modified within the spirit and scope thereof.
1. Asynchronous control method for a loom, the loom including a shedding device (2) that
includes a shedding motor (23) independent from a main shaft motor (13) of the loom
as a driving source and that displaces each of healds in an up-down direction as a
single drive shaft (22) that is common to all of the healds is driven by the shedding
motor (23),
the method comprising:
detecting a rotation amount of the drive shaft (22) in each weaving cycle at least
when the loom is performing a normal operation; and
controlling driving of the main shaft motor (13) so that a main shaft (12) of the
loom is rotated so as to be synchronized with the drive shaft (22) in accordance with
a detection signal indicating the detected rotation amount.
2. The synchronous control method for a loom according to claim 1,
wherein the controlling of driving of the main shaft motor (13) includes
rotating the main shaft (12) by a target rotation amount, the target rotation amount
being obtained based on the rotation amount of the drive shaft (22) that is detected
at each set period that is preset, in the set period from a time when the target rotation
amount is obtained,
detecting an actual rotation angle of the main shaft (12) at a time when a rotation
angle of the main shaft (12) is expected to reach a set angle that is a preset and
predetermined rotation angle of the main shaft (12),
obtaining a deviation of the actual rotation angle from the set angle by comparing
the detected actual rotation angle with the set angle, and
correcting, at a time when the deviation for a preset number of times is obtained,
the target rotation amount that is obtained for the set period after the time, based
on the deviation.
3. The synchronous control method for a loom according to claim 1 or 2,
wherein a control parameter that is used to control the main shaft motor (13) is changed
in accordance with a load that is applied to the drive shaft (22) as the healds are
displaced.
4. A loom comprising a shedding device (2) and a main shaft control device (14), the
shedding device (2) including a shedding motor (23) independent from a main shaft
motor (13) of the loom as a driving source and displacing each of healds in an up-down
direction as a single drive shaft (22) that is common to all of the healds is driven
by the shedding motor (23), the main shaft control device (14) controlling driving
of the main shaft motor (13),
the loom comprising:
a rotation detecting device that detects a rotation amount of the drive shaft (22)
in each weaving cycle at least when the loom is performing a normal operation; and
a synchronous control device (3) that obtains a rotation amount of a main shaft (12)
of the loom so that the main shaft (12) is synchronized with the drive shaft (22)
in accordance with a detection signal that is output from the rotation detecting device,
the synchronous control device (3) outputting a rotation command signal based on the
obtained rotation amount of the main shaft (12) to the main shaft control device (14).
5. The loom according to claim 4,
wherein the synchronous control device (3) includes
a calculating unit (31) that obtains a target rotation amount based on a rotation
amount of the drive shaft (22) that is detected at each set period that is preset,
the target rotation amount being a rotation amount by which the main shaft (12) is
to be rotated in the set period from a time when the target rotation amount is obtained,
an angle detector (33) that obtains an actual rotation angle of the main shaft (12)
at a time when a rotation angle of the main shaft (12) is expected to reach a set
angle that is a preset and predetermined rotation angle of the main shaft (12), and
a comparing unit (34) that obtains a deviation of the actual rotation angle obtained
by the angle detector (33) from the set angle by comparing the actual rotation angle
with the set angle, and
wherein the calculating unit (31) includes a correcting unit (36) that corrects, at
a time when the deviation for a preset number of times is obtained, the target rotation
amount that is obtained for the set period after the time, based on the deviation.
6. The loom according to claim 4 or 5,
wherein the synchronous control device (3) has a function of changing a control parameter
that is used to control the main shaft motor (13) in accordance with a load that is
applied to the drive shaft (22) as the healds are displaced.