Centralized loom control method with optimization of operating speed

A centralized loom control method employing a host computer for controlling the operation of a plurality of looms. Data base including data accumulated by recording past actual weaving conditions in stored in a memory device connected to the host computer. The host computer determines standard set value for which the looms are to be set by processing the specifications of a fabric to be woven entered therein and data fetched from the memory device through predetermined calculation or interpolation. The host computer compares a standard operating speed among the standard set values with a target operating speed at which the loom is to be operated, and changes the standard set values according to the result of comparison to provide new standard set values suitable for operation at the target operating speed.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a centralized loom control method and, 
more particularly, to centralized loom control techniques for quickly 
deciding control conditions meeting weaving conditions appropriate for 
weaving a new fabric of specifications, such as the total number of warp 
ends, pick spacing, the type and count of yarns. 
2. Prior Art 
Optimum loom control conditions are decided through test weaving on a test 
loom before weaving fabrics of new specifications. In the test weaving, a 
plurality of control parameters, such as the operating speed of the main 
shaft of the test loom, warp tension, operating phases of the retaining 
pin of the weft measuring and storing device and picking nozzles, and the 
pressure of a picking fluid (air), are varied to find optimum conditions. 
The test weaving is carried out to decide optimum weaving conditions by a 
trial-and-error method, in which tentative weaving conditions are decided 
on operator's experience and intuition, the results of test weaving under 
the tentative weaving conditions are evaluated, and the tentative weaving 
conditions are adjusted to better weaving conditions 
However, the trial-and-error method requires much time and labor, and 
skill. Such a troublesome procedure of deciding weaving conditions is an 
impediment particularly to rapidly supplying fabrics of new specifications 
to the market requiring rapid supply of diversified fabrics. 
The inventors of the present invention proposed a method and apparatus for 
correcting the tentative weaving conditions in U.S. Pat. No. 4,736,324 
(EPO Application No. 85 114 810.6). This proposed method stores data of 
weaving conditions collected in the past weaving operations in a computer, 
enters data of specifications of a fabric to be produced, decides standard 
weaving conditions with reference to the data stored in the computer, 
gives the standard weaving conditions to a loom, operates the loom under 
the standard weaving conditions, measures parameters indicating the 
condition of weaving operation, and corrects the standard weaving 
conditions on the basis of data obtained by measuring the parameters. 
However, the advancement of weaving techniques is not taken into 
consideration in the invention proposed in the previous patent 
application. Suppose that an advanced loom is capable of operating at an 
operating speed higher than an optimum operating speed for at obsolete 
loom determined on the basis of data obtained and accumulated by measuring 
the operating conditions of such an obsolete loom in weaving the same 
fabric. Thin, the standard operating speed is lower than the optimum 
operating speed for the advanced loom, and hence improvement in 
productivity cannot be achieved by the advanced loom even though the 
standard operating speed is corrected automatically within a narrow range 
of correction by the learning function of the control unit of the loom. 
SUMMARY OF THE INVENTION 
Accordingly, it is an object of the present invention to provide a 
centralized loom control method eliminating the drawbacks of the prior art 
and capable of properly correcting the standard weaving conditions decided 
on the basis of data of the past weaving conditions. 
In one aspect of the present invention, data accumulated in the past is 
stored in a memory device incorporated into a host computer for 
controlling a plurality of looms, standard set values are, divided by 
processing the data fetched from the memory device and data representing 
the specifications of a fabric through a predetermined operation or an 
interpolative operation, and a standard operating speed and a previously 
entered target operating speed are compared to decide new standard set 
values suitable for operation at the target operating speed. Then, data 
obtained by monitoring the operation of the loom controlled on the basis 
of the new standard set values and a plurality of standard values for the 
optimum control of the loom are compared in order of priority of the 
standard values, and then the standard set values are corrected on the 
basis of the result of comparison. 
In accordance with the present invention, upon the reception of the 
specifications of a fabric, the host computer decides standard set values 
automatically with reference to a large amount data obtained through the 
measurement of the past actual operating condition of looms, the looms are 
set for the standard set values, and then the host computer controls the 
looms collectively. Thus, the present invention omits the test weaving 
procedure and improves the efficiency of the looms. 
Particularly, since standard set values suitable for operation at a target 
operating speed stored previously in the host computer are decided, the 
standard set values are corrected to provide new standard set values and 
the loom is set for the new standard set values, the loom is not set for 
an operating speed excessively lower than the possible operating speed of 
the loom. Consequently, the loom operates for weaving at an ideal 
operating speed meeting the performance thereof. Thus, the advancement of 
weaving techniques is reflected on setting the operating speed of the 
loom, so that the productivity of the loom is improved. 
The above and other objects, features and advantages of the present 
invention will become more apparent from the following description taken 
in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIG. 1 showing a centralized loom controller for carrying out 
a centralized loom control method of the present invention, the 
centralized loom controller comprises, as principal components, a fabric 
data input means 1 for entering data representing the specifications of a 
fabric, a data base storage means 2 for storing a data base constructed by 
accumulating actual data obtained by recording data obtained by monitoring 
past actual weaving operation for fabrics of various kind, a set value 
calculating means 3 for processing fabric specifications entered by the 
fabric data input means 1 and actual data fetched from the data base 
storage means 2 through a predetermined operation to provide standard set 
values, a set value storage means 4 for storing new standard set values 
obtained on the basic of standard set values calculated by the set value 
calculating means 3 so as to meet a weaving operation at a target 
operating speed, a set value transmitting means 5 for transmitting the new 
set values to a plurality of loop control units 8 through 
transmitter-receiver means 81 connected respectively to the loom control 
units 8, an actual data receiving means 6 for receiving data representing 
the respective operating conditions of the looms and transmitted thereto 
through the transmitter-receiver means 81, and a set value changing means 
7 for changing the standard set values stored in the set value storage 
means 4 on the basis of the actual data received by the actual data 
receiving means 6. 
The centralized loom controller further comprises a target operating speed 
input means 41 and a set value correcting means 42. The set value 
correcting means 42 is connected to the data base storage means 2, the set 
value calculating means 3, the set value storage means 4 and the target 
operating speed input means 41. The set value correcting means 42 decides 
new set values appropriate for weaving operation at a target operating 
speed by correcting the standard set values calculated by the set value 
calculating means 3, and then gives the new set values to the standard set 
value storage means 4. 
The centralized loom controller thus constructed carries out the 
centralized loom control method of the present invention to decide quickly 
weaving conditions suitable for weaving operation at a target operating 
speed. 
Referring to FIG. 2 showing the construction of the centralized loom 
controller for carrying out the centralized loom control method of the 
present invention, a host computer 9 for the centralized control of the 
plurality of loom control units 8 integrally has functions equivalent to 
those of the set value calculating means 3, the set value storage means 4, 
the set value changing means 7 and the set value correcting means 42 shown 
in FIG. 1. A key board 10 and a display 11, such as a CRT, connected to 
the host computer 9 serve as the fabric data input means 1 and the target 
operating speed input means 1. The data base storage device 2, such as a 
floppy disk, is an external storage device connected to the host computer 
9. The plurality of loom control units 8 are connected through the 
transmitter-receiver 81, a bilateral bus 13 and a communication interface 
12 to the host computer 9. The communication interface 12 comprises the 
set value transmitting device 5 and the actual data receiving device 6. 
The operation of the centralized loom controller for weaving a fabric of 
new fabric specifications will be described hereinafter. 
The keyboard 10 is operated in an interactive mode watching the display 11 
to specify the number of the loom control unit 8 of an objective loom and 
to enter fabric specifications sequentially in the host computer 9 by a 
procedure as shown in FIG. 3. The fabric specifications include the kind 
of warp yarns, the yarn count (denier) of warp yarns, the total number of 
warp yarns, the kind of weft yarns, pick spacing, the yarn count of weft 
yarns and width in reed. 
Upon the reception of the fabric specifications for a new fabric, the host 
computer 9 calculates standard set values with reference to the actual 
data stored in the data base storage device 2. The data base storage means 
2 stores basic data and similar data prepared previously by recording the 
results of past actual weaving operation. 
Referring to FIGS. 4(a) and 5(a), snowing a procedure of calculating a 
standard total warp tension T (kg), a basic tension a (g/d) for a yarn of 
the same kind as that of warp yarns to be used is read from the data base 
storage device 2. Then, the standard total warp tension T is calculated by 
using an expression: 
EQU T (kg)=a (g/d).times.d (denier).times.N.times.1/1000 
where d is the yarn count of the warp yarn expressed in denier and N is the 
total number N of the warp yarns, which are entered by operating the 
keyboard 10. 
Referring to FIGS. 4(b) and 5(b) showing a procedure of calculating a 
standard pressure p for a picking fluid, a plurality of combinations of 
weft yarns of the same kind as that of the weft yarn to be used having 
yarn counts b.sub.i (i=1 to n) and corresponding pressures P.sub.i (i=1 to 
n) as shown in FIG. 6 are read from the data base storage device 2, Yarn 
counts b.sub.i and b.sub.i+1 and pressures P.sub.i and p.sub.i+1 meeting 
an inequality: b.sub.i &lt;b&lt;b.sub.i+1 are selected, and then the standard 
pressure P is calculated through interpolation (FIG. 7) by using an 
expression: 
EQU P=Pi+(P.sub.i+1 -P.sub.i)(b-b.sub.i)/(b.sub.i+1 -b.sub.i) 
A standard operating speed R.sub.1 and a standard picking phase t, namely, 
a phase at which an instruction to turn on or off a picking device is 
issued are calculated similarly through interpolation (FIGS. 8 and 9) by 
using actual data read from the data base storage device 2 by procedures 
shown in FIGS. 4(c) and 5(c) and FIGS. 4(d) and 5(d), respectively. 
Other standard set values are calculated by similar procedures. 
FIG. 10 is a flow chart showing steps 1 to 10 of calculating the foregoing 
standard set values. In step 3, a decision is made if the same fabric 
specifications as the new fabric specifications entered in the host 
computer 9 are found in the data base stored in the data base storage 
device 2. When the decision in step 3 is affirmative, the standard set 
values corresponding to the fabric specifications are fetched from the 
data base storage device 2. In such a case, the procedures for calculating 
the standard set values are unnecessary, and hence steps 4 through 8 are 
skipped. 
After the completion of steps 1 to 9, the target operating speed input 
device 41 is operated to give the host computer 9 a target operating speed 
R.sub.0 or a target difference corresponding to the difference .DELTA.R 
(=R.sub.0 -R.sub.1, R.sub.1 is the standard operating speed of the loom). 
Then, the host computer calculates the difference .DELTA.R. When 
.DELTA.R&lt;K (K is a constant), the standard set values are not changed. 
When .DELTA.R.gtoreq.K, standard set values dependent on the target 
rotating speed R.sub.0, such as the standard picking phase t, the standard 
pressure P and the standard total warp tension T, are corrected 
accordingly. That is, since the rotating angle of the main shaft of the 
loom corresponding to a delay .DELTA.T in the operation of the actuator is 
differentiated corresponding to the rotating speed of the loom, the 
standard picking phase t indicative of issuing an instruction signal to 
the actuator is changed according to the difference .DELTA.R so that the 
phase of the completion of operation of the actuator is kept constant. The 
standard phase t is corrected by the change thereof and calculated by 
using an expression: 
EQU C=(.theta.-.DELTA..theta.) 
where .DELTA..theta.(degree)=360.times..DELTA.R.times..DELTA.T (sec), C is 
correction. The pressure is determined by defining the relation between 
standard pressure P and rotating speed R by a regression function and 
correcting the standard pressure P by P=k.times.R+P.sub.0. Other standard 
set values to be corrected according to the operating speed other than 
those relating to picking conditions, such as stop signal output phase, 
are corrected by a similar procedure. Thus, the standard set values are 
corrected in steps 10 through 14. Then, in steps 15 and 16, the host 
computer 9 gives sequentially control signals representing the corrected 
standard set values through the communication interface 12 and the 
bilateral bus 13 to the loom control unit 8 of the loom assigned to 
weaving the fabric. 
Then, the loom control unit 8 sets the loom for weaving conditions 
corresponding to the corrected standard set values represented by the 
control signals specifying the new fabric specifications and the operating 
speed 
The operation of the centralized loom controller for the optimum control of 
the loom will be described hereinafter. 
Reference values for optimum control, namely, reference upper and lower 
limits of factors of optimum control, are entered sequentially in the host 
computer 9 in order of priority, for example, in order of (1) a reference 
operating rate, (2) a reference operating speed, (3) a reference total 
warp tension and (4) a reference pressure. The reference lower limit for 
operating rate having the highest priority may be omitted. After the loom 
has been set for the standard set values and started, the 
transmitter-receiver means 81 of the loom control unit 8 of the loom sends 
data representing the actual operating conditions of the loom through the 
bilateral bus 13 and the communication interface 12 to the host computer 
9. 
The host computer 9 sequentially compares the data representing the actual 
operating conditions of the loom and the reference values for optimum 
control given thereto in order to priority, and then corrects the standard 
set values with reference to the result of comparison. 
Ordinarily, such a series of procedures for optimum control is carried out 
by the set value changing, device 7 and the set value storage device 4 
included in the host computer 9. However, when a microcomputer 
incorporated into the loom control unit 8 has a margin for control 
capacity, the series of procedures may be carried out by the loom control 
unit 8, in which the microcomputer of the loom control unit 8 executes a 
control program for optimum control in cooperation with the host computer 
9. 
FIGS. 11(a) and 11(b) are flow charts showing steps of procedures for 
optimum control, which are repeated periodically. 
Suppose that the operating rate of the loom is excessively lower than the 
reference operating rate, i.e., a reference value having the highest 
priority, owing to highly frequent stoppage of the loom due to warp 
breakage, that is, a decision in step 1 is negative and a decision in step 
2 is affirmative. Then, in steps 3 through 7, the standard set values of 
total warp tension having the third priority is reduced to a value not 
less than the lower limit of total warp tension. If the actual operating 
rate still falls short of the reference operating rete, the reference 
operating speed, i.e., a reference value having the second priority, is 
lowered to a value not less than the lower limit of operating speed in 
steps 8 through 11. 
When the operating rate of the loom is excessively lower than the reference 
operating rate owing to highly frequent stoppage of the loom due to faulty 
picking, that is, when both the decisions in steps 1 and 2 are negative, 
the reference pressure of the picking fluid, i.e., a reference value 
having the fourth priority, is increased to a value less than the upper 
limit of the pressure in steps 12 through 16, and then the reference total 
warp tension, i.e., a reference value having the third priority, is 
reduced to a value not less than the lower limit of total warp tension in 
steps 17 through 20 and 16. If the operating rate still falls short of the 
reference operating rate, the operating speed having the second priority 
is lowered further to a value not less than the lower limit in steps 21 
through 24 and 16. 
On the contrary, when the operating rate is very high, namely, when the 
decision in step 1 is affirmative, the operating speed and the total warp 
tension are increased to values which will not reduce the operating rate 
below the lower limit of the reference operating rate in steps 25 through 
33. When the loom is still able to operate without trouble, the reference 
pressure is decreased in steps 34 through 37 and 29. In steps 30 to 33, 
the choice of either the upper limit or the lower limit as the optimum 
value is decided in entering the reference value in the host computer 9. 
In this embodiment, the upper limit of the reference total warp tension is 
chosen as an optimum value. 
Although the invention has been described in its preferred form with a 
certain degree of particularity, it is to be understood that many 
variations and changes are possible in the invention without departing 
from the scope thereof.