U.S. patent application number 09/938822 was filed with the patent office on 2002-02-28 for method of directly determining setting values for the application point of regulation in a regulated draw frame.
Invention is credited to Breuer, Joachim, Hartung, Reinhard.
Application Number | 20020023315 09/938822 |
Document ID | / |
Family ID | 7653826 |
Filed Date | 2002-02-28 |
United States Patent
Application |
20020023315 |
Kind Code |
A1 |
Breuer, Joachim ; et
al. |
February 28, 2002 |
Method of directly determining setting values for the application
point of regulation in a regulated draw frame
Abstract
A method of directly determining setting values for an
application point of regulation in a draw unit for drafting sliver,
includes the following steps: obtaining a plurality of measured
values of a quality-characterizing magnitude, such as a CV value,
of the drafted sliver portion; utilizing the measured values for
formulating a function having a minimum constituting an optimal
application point of regulation for controlling the draw unit;
determining the optimal application point of regulation in a
pre-operational run of the draw unit; obtaining several measured
values of a quality-characterizing magnitude based on an un-drafted
sliver portion and determining the function between the
quality-characterizing magnitudes and application points of
regulation from measured values at the un-drafted sliver portion
and at the drafted sliver portion.
Inventors: |
Breuer, Joachim; (Aachen,
DE) ; Hartung, Reinhard; (Monchengladbach,
DE) |
Correspondence
Address: |
VENABLE, BAETJER, HOWARD and CIVILETTI, LLP
P.O. BOX 34385
Washington
DC
20043-9998
US
|
Family ID: |
7653826 |
Appl. No.: |
09/938822 |
Filed: |
August 27, 2001 |
Current U.S.
Class: |
19/239 ; 19/150;
19/240 |
Current CPC
Class: |
D01H 13/32 20130101;
D01H 5/42 20130101 |
Class at
Publication: |
19/239 ; 19/240;
19/150 |
International
Class: |
D01H 005/32 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 25, 2000 |
DE |
100 41 893.7 |
Claims
What is claimed is:
1. In a method of directly determining setting values for an
application point of regulation in a draw unit for drafting
advancing sliver; the method including the steps of obtaining a
plurality of measured values of a quality-characterizing magnitude
of a drafted sliver portion; utilizing the measured values for
formulating a function having a minimum constituting an optimal
application point of regulation for controlling the draw unit;
determining the optimal application point of regulation in a
pre-operational run of the draw unit; the improvement comprising
the steps of obtaining several measured values of a
quality-characterizing magnitude based on an un-drafted sliver
portion and determining said function between said
quality-characterizing magnitudes and application points of
regulation from measured values at the un-drafted sliver portion
and at the drafted sliver portion.
2. The method as defined in claim 1, wherein said
quality-characterizing magnitude is a CV value.
3. The method as defined in claim 1, further comprising the step of
obtaining several measured values of at least one
quality-characterizing magnitude measured on one of said un-drafted
and drafted sliver portions.
4. The method as defined in claim 1, further comprising the step of
combining corresponding measured values of quality-characterizing
magnitudes with respect to the application point of regulation at
the un-drafted sliver portion and at the drafted sliver portion to
a quality-characterizing number QK and forming a function of the
quality-characterizing numbers QK; said function having a minimum
corresponding to an optimal application point of regulation
R.sub.opt.
5. The method as defined in claim 1, further comprising the step of
obtaining two different quality-characterizing magnitudes measured
at the drafted sliver portion.
6. The method as defined in claim 1, further comprising the step of
obtaining a plurality of different quality-characterizing
magnitudes measured at sliver length portions of different
length.
7. The method as defined in claim 1, further comprising the steps
of storing at least three quality-characterizing numbers in a
memory; formulating the function; and determining the minimum of
the function by computation.
8. The method as defined in claim 1, further comprising the steps
of determining R.sub.opt during a test run, applying R.sub.opt to a
preliminary drafting control of the draw unit prior to normal
operation and performing a plausibility check.
9. The method as defined in claim 1, wherein said draw unit has
output delivery rolls; further comprising the step of measuring the
quality-characterizing magnitude of the drafted sliver downstream
of the delivery rolls, as viewed in a direction of sliver
advance.
10. The method as defined in claim 1, further comprising the step
of obtaining the measured values during a test run of the draw unit
within a time period during which one coiler can is filled with
sliver as outputted by the draw unit.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority of German Application
No. 100 41 893.7 filed Aug. 25, 2000, which is incorporated herein
by reference.
BACKGROUND OF THE INVENTION
[0002] This invention relates to a method of directly determining
setting values for the application point of regulation in a
regulated draw frame for slivers. The control system of the draw
frame in which the extent of draft of the sliver may be set has at
least one preliminary control system for changing the draft of the
sliver. Based on the drafted sliver, a number of
quality-characterizing measured values, such as CV values may be
sensed and utilized for formulating a function whose minimum
represents an optimum application point of regulation for the
control of the draw frame. The optimized application point of
regulation may be determined in a pre-operational test run or a
setting run of the draw frame.
[0003] The application point of regulation is an important setting
magnitude in a draw frame to produce slivers with a high sliver
uniformity, that is, with a small CV value.
[0004] In a known system, during a pre-operational setting run, the
sliver is drafted between the mid rolls and the output rolls of the
draw unit and is withdrawn by calender rolls which are adjoined by
a measuring device for the CV value of the drafted sliver. In the
pre-operational setting run a plurality of CV values are determined
which represent a quality-characterizing magnitude for the drafted
sliver. Based on such measured values, a function is formulated
whose minimum value corresponds to a value which promises to be the
best adaptation of the regulation actual sliver. The plurality of
measured values which are plotted and based on which the function
is formulated, are in each instance measured for a different
setting value of the regulation. Thus, for the definition of the
function to be evaluated, each incremental value of an
incrementally changing parameter, for example, the application
point of regulation of the "electronic memory", has to be
associated with one of the measured values. It is a disadvantage of
this system that the quality of the un-drafted sliver (input
quality) introduced into the draw unit cannot be taken into
consideration. It is a further drawback that only one certain CV
value is considered.
SUMMARY OF THE INVENTION
[0005] It is an object of the invention to provide an improved
method of the above-outlined type from which the discussed
disadvantages are eliminated and which, in particular, ameliorates
the determination and setting of the optimal application point of
regulation at the regulating system of a draw unit.
[0006] These objects and others to become apparent as the
specification progresses, are accomplished by the invention,
according to which, briefly stated, the method of directly
determining setting values for an application point of regulation
in a draw unit for drafting sliver, includes the following steps:
obtaining a plurality of measured values of a
quality-characterizing magnitude, such as a CV value, of the
drafted sliver portion; utilizing the measured values for
formulating a function having a minimum constituting an optimal
application point of regulation for controlling the draw unit;
determining the optimal application point of regulation in a
pre-operational run of the draw unit; obtaining several measured
values of a quality-characterizing magnitude based on an un-drafted
sliver portion and determining the function between the
quality-characterizing magnitudes and application points of
regulation from measured values at the un-drafted sliver portion
and at the drafted sliver portion.
[0007] The optimal application point of regulation (optimal dead
period or delay) is determined by the draw frame itself by using
the steps according to the invention. Based on the CV values of the
sliver measured on line, the draw frame control system determines
the optimal application point of regulation, that is, the machine
optimizes itself. By utilizing the CV values of both the un-drafted
and the drafted sliver the application point of regulation is
determined more accurately, since effects of the incoming sliver
too, such as those caused by thickness changes, are taken into
consideration. Further, a more rapid determination of the
application point of regulation is feasible.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a schematic side elevational view of a regulated
draw frame including a system for practicing the invention.
[0009] FIG. 1a is a block diagram of a separate preliminary control
device.
[0010] FIG. 2 is an enlarged schematic side elevational view of one
part of the FIG. 1 structure, illustrating the principal drafting
field with indication of the principal drafting point.
[0011] FIG. 3 is a diagram illustrating the effect of the
application point of regulation on the on-line CV value.
[0012] FIG. 4 illustrates a visual representation of an automatic
determination of the optimal application point of regulation.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0013] FIG. 1 illustrates a draw frame 1 which may be, for example,
an HSR model manufactured by Trutzschler GmbH & Co. KG,
Monchengladbach, Germany.
[0014] The draw frame 1 includes a draw unit 2 having an upstream
draw unit inlet 3 and a downstream draw unit outlet 4. The slivers
5 are taken from non-illustrated coiler cans and are introduced
into a sliver guide 6 which includes a measuring member 9 and from
which they are withdrawn by calender rolls 7, 8.
[0015] The draw unit 2 is a 4-over-3 construction, that is, it is
formed of a lower output roll I, a lower middle roll II and a lower
input roll III as well as four upper rolls 11, 12, 13 and 14. The
draw unit 2 drafts the sliver 5', composed of a plurality of
slivers 5, in a preliminary and principal drafting field. The roll
pairs III,14 and II,13 constitute the preliminary drafting field
whereas the roll assembly II,11,13 and the roll pair I,12
constitute the principal drafting field. The roll pair II,13 is
immediately followed by a pressure bar 30. The drafted slivers 5
are introduced in the draw unit outlet 4 into a sliver guide 10 and
are, by means of calender rolls 15, 16, pulled through a sliver
trumpet 17 in which the slivers are combined into a single sliver
18 which is subsequently deposited in coiler cans. The direction of
the sliver passing through the draw frame 1 is designated at A.
[0016] The calender rolls 7, 8, the lower input roll III and the
lower middle roll II which are mechanically coupled to one another,
for example, by means of a toothed belt, are driven by a regulating
motor 19 to which a desired rpm value may be applied. The
respective upper rolls 14 and 13 are driven by the respective lower
rolls by friction. The lower output roll I and the calender rolls
15, 16 are driven by a principal motor 20. The regulating motor 19
and the principal motor 20 each have a respective regulator 21, 22.
Each rpm regulation occurs by means of a closed regulating circuit
which includes a tachogenerator 23 connected with the motor 19 and
the regulator 21, as well as a tachogenerator 24 connected with the
motor 20 and the regulator 22.
[0017] At the draw unit inlet 3 a mass-proportionate magnitude, for
example, the sliver cross section is measured by the inlet
measuring organ 9 which is known, for example, from German patent
document DE-A-44 04 326. At the draw unit outlet 4 the cross
section of the exiting sliver 18 is sensed by an outlet measuring
member 25 which is associated with the sliver trumpet 17 and which
is known, for example, from German patent document DE-A-195 37 983.
A central computer unit 26 (control and regulating device), for
example, a microcomputer with microprocessor, transmits a setting
of the desired value to the regulator 21 for the regulating motor
19. The measured values from both measuring members 9 and 25 are
transmitted to the central computer unit 26 during the drafting
process. The desired rpm value for the regulating motor 19 is
determined by the central computer unit 26 from the measured values
sensed by the intake measuring member 9 and from the desired value
for the cross section of the exiting sliver 18. The measured values
of the outlet measuring member 25 serve for monitoring the exiting
sliver 18. With the aid of such a regulating system fluctuations in
the cross section of the inputted slivers 5 may be compensated for
by suitable regulation of the drafting process to obtain an evening
of the sliver. A monitor 27, an interface 28, an inputting device
29 and a memory 31 are also connected to the computer 26.
[0018] While the preliminary control system may be integrated into
the central computer unit 26 as shown in FIG. 1, according to FIG.
1a, a separate preliminary control system 33 may be provided which
is connected between the computer unit 26 and the regulator 21. The
computer unit 26 changes the application point of regulation R of
the preliminary control system 33.
[0019] The measured values, for example, thickness fluctuations of
the sliver 5, obtained from the measuring member 9 are applied to
the memory 31 with a variable delay. As a result of such a delay
the change in the draft of the sliver in the principal drafting
field according to FIG. 2 occurs at a moment when the sliver region
measured earlier by the measuring member 9 and deviating from the
desired value is situated in the principal drafting point 32. When
such a sliver region reaches the principal drafting point 32 the
respective measured value is called from the memory 31.
[0020] The distance between the measuring location of the measuring
member 9 and the drafting location at the principal drafting point
32 is the application point of regulation R.
[0021] The apparatus according to the invention makes possible a
direct determination of the setting values for the application
point of regulation R. A plurality of measured values of the sliver
thickness for different lengths of the exiting sliver 5'" (drafted
sliver) are taken from the measuring member 25 in the sliver
trumpet, and three CV values (CV.sub.1 m, CV.sub.10 cm, CV.sub.3
cm) are calculated as quality-characterizing magnitudes. In a
similar manner the measuring member 9 in the sliver guide 6 takes
thickness measurements of a determined length of the un-drafted
sliver 5, and from these measured magnitudes quality-characterizing
CV values (CV.sub.in) are calculated. The determination of the CV
values occurs preferably for four application points of regulation
R. Expediently, in each instance two application points of
regulations R are selected on the one side and two application
points of regulation R are selected on the other side of the
optimal application point of regulation R.sub.opt. In each instance
a quality-characterizing number QK is determined by calculation
from the CV values of the un-drafted sliver 5 and the drafted
sliver 5'". Further, a function between the numbers QK and the
corresponding application points of regulation R are calculated in
the computer 26 and displayed on the screen 27 (FIGS. 3 and 4). A
polynomial of the second degree is determined from the four values
of the application point of regulation R and the respective
quality-characterizing numbers QK, and subsequently the minimum of
the curve is calculated. The minimum point of the function
corresponds to the optimum application point of regulation
R.sub.opt (see FIG. 4). In this manner, based on the drafted sliver
5'", several measured values of three different CV values and based
on the un-drafted sliver 5, several measured values of a CV value
are utilized, and those CV values which correspond to one another
in relation to the application point of regulation R are combined
to a quality number QK. Based on several quality numbers QK a
function is formulated by computation, whose minimum point
corresponds to the optimum application point of regulation
R.sub.opt.
[0022] During operation, in a setting run or test run, as a first
step a predicted first value for the application point of
regulation, for example, R.sub.-5 is set. This value is preferably
an empirical value. Inputting may occur by the inputting device 29
or by calling the data from a memory. Subsequently, the following
steps are taken:
[0023] The sliver quality measured on-line for each setting of an
application point of regulation is determined in each instance over
a sliver length of 250-300 m.
[0024] The measurements for optimizing the application point of
regulation are performed on a sliver length without coiler can
exchange; this may occur, for example, while the draw frame is at a
standstill between the individual application points of regulation
R.
[0025] The determination of the on-line measured sliver quality is
effected based on the following quality values:
[0026] Output sliver quality: CV.sub.3 cm, CV.sub.10 cm, CV.sub.1 m
(determined, for example, by a sensor arrangement 25 at the draw
frame outlet 4 which may be a SLIVER-FOCUS model manufactured by
Trutzschler GmbH & Co. KG).
[0027] Input sliver quality is described by CV.sub.in (this is
performed at the sensor device 9).
[0028] From the above different quality values a
quality-characterizing number QK is determined by the following
formula:
QK=CV.sub.3 cm+CV.sub.10 cm+CV.sub.1 cm-CV.sub.in
[0029] With the above quality-characterizing number a sliver
quality is sufficiently determined:
[0030] QK high.fwdarw.bad quality
[0031] QK low.fwdarw.good quality.
[0032] Based on the QK equation, the natural scattering of the
individual values is reduced and outlier values are not evaluated
beyond what they are worth. The formation of a mean value leads to
more exact predictions, and the influence of the regulation for
both long and short wavelengths is taken into consideration. Even
the influence of the input quality (sliver 5) is taken into
consideration in the computation.
[0033] The QK values which are computed from the real CV values
obtained during tests are utilized for developing steps 4, 5, 6, 7
and 8 described below.
[0034] The course of the quality curve above the application point
of regulation R is always symmetrical to the minimum value of the
curve (FIG. 3), that is, in case of an optimum application point of
regulation R=0, the CV value deterioration at -4 is of the same
extent as at +4. The functional relationship is described based on
the symmetry by a polynomial of the second degree.
[0035] Preferably, the region between -5 and +5 is to be considered
so that the quality differences are sufficiently substantial and,
at the same time, the level of the application point of regulation
remains realistic.
[0036] Reductions of three to four values for the application point
of regulation R yield sufficient locations of reference (four
pieces):
[0037] -5 -4 -3 -1 0 1 2 3 4 5
[0038] A polynomial of second degree (symmetrical course) is
determined, with the aid of numerical solution process, from the
four values for the application point of regulation R and the
respective QK values.
[0039] Thereafter, by means of numeric processes the minimum of the
curve is determined.
[0040] Such a minimum value is the optimum application point of
regulation R in the then applicable machine setting and given fiber
material (FIG. 4).
[0041] By visual observation (monitor screen 27) an automatic
determination of the application point of regulation may be
displayed for the operator in a reproducible manner (FIG. 4).
[0042] A number of different CV values of different sliver length
portions are compared with one another and in addition to the
output quality (sliver 5'"), the input quality too, is taken into
consideration as an important quality characteristic. Further, the
principal drafting point is calculated from the minimum of a
polynomial of the second degree, that is, a symmetrical course.
Based on an algorithm, several different CV values are combined to
a quality-characterizing number QK. From the application points of
regulation R and the corresponding quality-characterizing numbers a
function is constructed by approximation. The minimum is calculated
from the resulting function course. The determination is effected
during pre-operational test run or setting run. The optimum
application point of regulation R.sub.opt is taken over prior to
beginning of the regular production by the control system 26, 33
and a consistency inquiry is performed, possibly with error
reports, and the result is reproducibly shown to the operator in a
graphical representation. Four quality-characterizing numbers QK
are obtained for determined application points of regulation R.
These four quality-characterizing numbers are stored in a memory
and based thereon a function curve is approximated. Only thereafter
is the minimum of the function curve calculated. For each
quality-number a few meters of sliver are delivered. The
quality-characterizing magnitude (CV value) is determined between
the delivery roll and the location of sliver deposition (output) as
well as the measuring device 9 at the draw unit input 3. The test
run is performed during the charging of one coiler can. Between the
four application points of regulation R (reference locations) the
draw frame is stopped. The defined four application points of
regulation R have different distances from one another.
[0043] The automatic optimization according to the invention of the
application point of regulation has, among others, the following
advantages:
[0044] Faster optimization of the application point of
regulation;
[0045] Optimization is performed with economy of material;
[0046] No need to utilize laboratory equipment or
Uster-testers;
[0047] CV values for the optimization are no longer distorted by
effects such as coiler can deposition, climatic influences, and the
like. In this manner, a better optimization result is achieved;
[0048] Realization of a "self-optimizing draw frame";
[0049] Effective utilization of the machine control system
(computer 26);
[0050] By means of the automatic optimization the optimum
application point of regulation may be found even if the data of
the working memory and the data of the mechanical setting do not
agree with one another; and
[0051] Knowledge transfer for performing at the manual optimization
to the utilizer (operator) is dispensed with.
[0052] By virtue of the automatic determination of the application
point of regulation (principal drafting point) not only the sliver
uniformity but also, to the same extent, the CV values of the yarn
quality may be improved. This was found in wool spinning products
and PES/BW mixtures.
[0053] The invention was explained in connection with a regulated
draw frame 1. It is to be understood that it may find application
in other machines which include a regulated draw unit 2, such as a
carding machine, a combing machine and the like.
[0054] It will be understood that the above description of the
present invention is susceptible to various modifications, changes
and adaptations, and the same are intended to be comprehended
within the meaning and range of equivalents of the appended
claims.
* * * * *