U.S. patent application number 12/520763 was filed with the patent office on 2010-04-15 for method and device for the control of a feed mechanism.
This patent application is currently assigned to manroland AG. Invention is credited to Bernd Mehlis, Raimond Posselt, Ulrich Seyffert.
Application Number | 20100089962 12/520763 |
Document ID | / |
Family ID | 39241587 |
Filed Date | 2010-04-15 |
United States Patent
Application |
20100089962 |
Kind Code |
A1 |
Mehlis; Bernd ; et
al. |
April 15, 2010 |
Method and Device for the Control of a Feed Mechanism
Abstract
A method for the control of a feed mechanism of a web-fed
printing press, i.e., for the control of tensile stress and/or web
tension of a printing material web to be taken into the printing
unit by the feed mechanism, wherein thereby an actual value is
compared with a desired value. According to the discrepancy between
the actual value and the desired value, a control device for the
tensile stress and/or the web tension produces a correcting
variable for the feed mechanism. The actual value of the tensile
stress and/or the web tension is determined by calculation based on
a model.
Inventors: |
Mehlis; Bernd; (Plauen,
DE) ; Posselt; Raimond; (Reichenbach, DE) ;
Seyffert; Ulrich; (Syrau, DE) |
Correspondence
Address: |
COHEN, PONTANI, LIEBERMAN & PAVANE LLP
551 FIFTH AVENUE, SUITE 1210
NEW YORK
NY
10176
US
|
Assignee: |
manroland AG
Offenbach am Main
DE
|
Family ID: |
39241587 |
Appl. No.: |
12/520763 |
Filed: |
December 20, 2007 |
PCT Filed: |
December 20, 2007 |
PCT NO: |
PCT/EP2007/011272 |
371 Date: |
July 22, 2009 |
Current U.S.
Class: |
226/1 ;
226/10 |
Current CPC
Class: |
B41F 13/03 20130101;
B65H 2801/21 20130101; B65H 23/195 20130101; B65H 2557/24 20130101;
B65H 23/188 20130101; B65H 2301/522 20130101 |
Class at
Publication: |
226/1 ;
226/10 |
International
Class: |
B65H 23/188 20060101
B65H023/188 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 22, 2006 |
DE |
10 2006 061 252.3 |
Claims
1.-10. (canceled)
11. A method for automatically controlling at least one of a web
tensile stress and a web tension of a web of printing material
drawn into a printing unit by a feed mechanism, the method
comprising: comparing an actual value of at least one of a web
tensile stress and a web tension of a web of printing material of a
drive of the feed mechanism with a setpoint value of the drive of
the feed mechanism; generating a correction variable for the feed
mechanism based at least in part on the deviation of the actual
value of the drive of the feed mechanism from the setpoint value of
the drive of the feed mechanism; and computing the actual value of
the at least one of the web tensile stress and the web tension
based on a model.
12. The method in accordance with claim 10, wherein an input to the
model comprises at least one of: a motor torque of a drive of the
feed mechanism an electric current that creates the motor torque, a
friction torque of the feed mechanism, a web tensile stress value,
a web tension value supplied by a reel changer located upstream of
the feed mechanism, a quantity that forms the web tensile stress
value, and a quantity that forms the web tension value.
13. The method in accordance with claim 12, wherein the friction
torque of the feed mechanism is a constant friction torque.
14. The method in accordance with claim 13, wherein the model
determines the actual value of at least one of the web tensile
stress and the web tension as follows:
X.sub.IST=G2X.sub.RWa*[G1(M.sub.MOT)+c] where X.sub.IST is the
computed actual value of the at least one of the web tensile stress
and the web tension, X.sub.RW is the value of at least one of the
web tensile stress and the value of the web tension of the reel
changer, M.sub.MOT is the motor torque of the drive, G1 and G2 are
smoothing functions, and a and c are constants.
15. The method in accordance with claim 12, wherein the friction
torque of the feed mechanism is a speed-dependent friction torque
and, the input to the model further comprises the speed of the
drive of the feed mechanism.
16. The method in accordance with claim 15, wherein the model
determines the actual value of the at least one of the web tensile
stress and the web tension as follows:
X.sub.IST=G2(X.sub.RW)+a*[G1(M.sub.MOT)+m*N.sub.IST+c] where
X.sub.IST is the computed actual value of the web tensile stress
and/or the web tension, X.sub.RW is the value of the web tensile
stress and/or the value of the web tension of the reel changer,
M.sub.MOT is the motor torque of the drive, G1 and G2 are smoothing
functions, N.sub.IST is the speed of the drive, and a, m, and c are
constants.
17. The method in accordance with claim 11, wherein the method
further comprises: superimposing the automatic control of the at
least one of the web tensile stress and the web tension on an
automatic control of a speed of the drive of the feed mechanism;
and outputting an offset for a setpoint value of the speed of the
drive of the feed mechanism as a correcting variable.
18. The method in accordance with claim 11, wherein the method
further comprises: superimposing the automatic control of the at
least one of the web tensile stress and the web tension on an
automatic control of a state of the drive of the feed mechanism;
and outputting an offset for a setpoint value of the state of the
drive of the feed mechanism as a correcting variable.
19. A device for automatically controlling the at least one of a
web tensile stress and a web tension of a web of printing material
to be drawn into a printing unit by a feed mechanism, the device
comprising: a control system for the at least one of the web
tensile stress and the web tension configured to generate a
correcting variable for the feed mechanism as a function of a
deviation of an actual value of the at least one of the web tensile
stress and the web tension from a setpoint value of the at least
one of the web tensile stress and the web tension, wherein the
device is further configured to determine the actual value the at
least one of the web tensile stress and the web tension based on a
model.
20. A device in accordance with claim 19, wherein the device for
automatic controlling the at least one of a web tensile stress and
a web tension is integrated in a drive controller of a drive of the
feed mechanism.
21. The method in accordance with claim 15, wherein the
speed-dependent friction torque is linearized.
Description
PRIORITY CLAIM
[0001] This is a U.S. national stage of application No.
PCT/EP2007/011272, filed on 20 Dec. 2007, which claims Priority to
the German Application No.: 10 2006 061 252.3, filed: 22 Dec. 2006;
the contents of both being incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention concerns a method for automatically
controlling a feed mechanism of a web-fed printing press. The
invention also concerns a device for automatically controlling a
feed mechanism of a web-fed printing press.
[0004] 2. Prior Art
[0005] It is already well known from practice that webs of printing
material can be drawn into printing units of a web-fed printing
press by feed mechanisms. A feed mechanism, the purpose of which is
to draw a web of printing material into a printing unit of a
web-fed printing press, has at least one roll driven by a drive
unit of the feed mechanism. The driven roll of the feed mechanism
is operated at a lower speed of revolution or peripheral speed than
the rolls or cylinders of the printing unit that serve to convey
the web of printing material, so that a well-defined web tensile
stress is produced between the feed mechanism and the printing unit
for the web of printing material that is to be drawn in. The web
tensile stress is a force, and the web tension is calculated from
the web tensile stress by dividing the web tensile stress by the
width of the web of printing material that is to be drawn in.
[0006] It is known from EP 0 976 674 B2 that the web tension can be
automatically controlled by comparing an actual value of the web
tension with a corresponding setpoint value, where a control unit
generates a correcting variable for the feed mechanism, depending
on the difference between the actual value and the set point or the
deviation of the actual value from the set point. According to EP 0
976 674 B2, a measured actual value of the web tension is used,
from which it follows that a suitable measuring device is necessary
for measuring the web tension. The use of a measuring device for
the web tension necessitates a complex design of the feed mechanism
and of the web-fed printing press which increases the feed
mechanism's costs.
SUMMARY OF THE INVENTION
[0007] An object of the present invention is to create a novel
method and device for automatically controlling a feed mechanism of
a web-fed printing press.
[0008] In accordance with one embodiment of the invention, the
actual value of the web tensile stress and/or the web tension is
determined mathematically based on a model.
[0009] Accordingly, there is no need for a measuring device or a
sensor for determining an actual value of the web tensile stress
and/or the web tension. This results in a simpler design of the
feed mechanism and the web-fed printing press with less complexity
and thus lower costs.
[0010] The automatic control of the web tensile stress and/or the
web tension is preferably superimposed on the automatic control of
a speed of the drive of the feed mechanism or on the automatic
control of a state of the drive of the feed mechanism.
[0011] The invention is described in greater detail below with
reference to specific embodiments, but it is not limited to these
embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a schematic section of a web-fed printing press to
illustrate one embodiment the invention;
[0013] FIG. 2 is a schematic drawing of a preferred automatic
control design for a drive of a feed mechanism of the web-fed
printing press;
[0014] FIG. 3 is a signal-flow diagram of a model for
mathematically determining an actual value of the web tensile
stress and/or the web tension; and
[0015] FIG. 4 is a signal-flow diagram of another model for
mathematically determining an actual value of the web tensile
stress and/or the web tension.
DETAILED DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a schematic section of a web-fed printing press in
the area of two printing units 10, 11 arranged one above the other
and a reel changer 12 located upstream of the two printing units
10, 11. In the vicinity of the reel changer 12, a web printing
material is kept ready in the form of a roll of printing material
13 and is unwound from the roll of printing material 13 as a web of
printing material 14. The web of printing material 14 is drawn into
the printing unit 10 by means of a feed mechanism 15 assigned to
the printing unit 10. The feed mechanism 15 has a roll 17, which is
driven by a drive 16 and serves the purpose of drawing the web of
printing material 14 into the printing unit.
[0017] The printing units 10, 11 are preferably 8-cylinder printing
units. Accordingly, each of the printing units 10, 11 has four
printing couples, and each printing couple has a form cylinder 18
and a transfer cylinder 19. The transfer cylinders 19 of each pair
of printing couples roll against each other to form a nip for the
web of printing material 14. The transfer cylinders 19 also take on
the function of further conveyance of the web of printing material
14 through the printing units 10, 11. The roll 17 of the feed
mechanism 15 is driven at a different speed of rotation or
peripheral speed from the transfer cylinders 19 of the printing
units 10, 11 in order to produce a well-defined web tensile stress
and/or a well-defined web tension for the web of printing material
14.
[0018] A drive controller 20 is assigned to the drive 16 of the
feed mechanism 15. FIG. 2 shows the preferred configuration of the
drive controller 20. The drive controller 20 illustrated in FIG. 2
automatically controls not only the web tensile stress and/or the
web tension of the web of printing material but also the speed of
the drive 16. Accordingly, the drive controller 20 of FIG. 2
comprises a control system 21 for automatically controlling the
speed of the drive 16. This speed controller 21 outputs a
correcting variable Y.sub.MOT for the drive 16 based on the
deviation of a measured actual value N.sub.IST of the speed of the
drive 16 from a setpoint value N.sub.SOLL for the speed of the
drive 16. A speed sensor 22 is assigned to the drive 16 to make the
measurement of the actual value N.sub.IST of the drive 16.
[0019] Automatic control of the web tensile stress and/or the web
tension is superimposed on the automatic speed control. The drive
controller 20 comprises, in addition to the speed controller 21, a
control system 23 for automatically controlling the web tensile
stress and/or the web tension. On the basis of the deviation
between a setpoint value X.sub.SOLL for the web tensile stress
and/or the web tension and a corresponding actual value X.sub.IST,
the control system 23 for automatically controlling the web tensile
stress and/or the web tension determines a correcting variable
Y.sub.N for the feed mechanism 15. In the specific embodiment of
FIG. 2, this set point Y.sub.N for the feed mechanism 15 is an
offset for the set point N.sub.SOLL of the speed of the drive
16.
[0020] In accordance with one embodiment of the present invention,
the actual value X.sub.IST of the web tensile stress and/or the web
tension is not determined by measurement but rather mathematically
based on a model. The output variable of the model 24 is the actual
value X.sub.IST for the web tensile stress and/or the web tension.
In the specific embodiment of FIG. 2, the following input variables
are supplied to the model 24: a motor torque M.sub.MOT of the drive
16, which is measured by a torque sensor 25, the actual value
N.sub.IST of the speed of the drive 16, which is measured by the
speed sensor 22, a web tensile stress value and/or web tension
value X.sub.RW of the reel changer 12, and a friction torque
M.sub.REIB of the feed mechanism 15. The friction torque M.sub.REIB
of the feed mechanism 15 is a speed-dependent quantity, where the
friction torque is preferably linearized
M.sub.REIB=m*N.sub.IST+c.
[0021] The model 24 according to FIG. 4 then determines the actual
value X.sub.IST of the web tensile stress and/or the web tension as
follows:)
X.sub.IST=G2(X.sub.RW)+a*[G1(M.sub.MOT)+m*N.sub.IST+c]
where:
[0022] X.sub.IST is the computed actual value of the web tensile
stress and/or the web tension,
[0023] X.sub.RW is the value of the web tensile stress and/or the
value of the web tension of the reel changer,
[0024] M.sub.MOT is the motor torque of the drive,
[0025] N.sub.IST is the speed of the drive,
[0026] G1 and G2 are smoothing functions,
[0027] and a, m, and c are constants.
[0028] In one embodiment, instead of the motor torque M.sub.MOT of
the drive 16, an electric current that creates the motor torque is
determined by measurement and used as the input quantity for the
model 24. Likewise, instead of the web tensile stress value and/or
the web tension value of the reel changer, it is possible to use a
quantity that creates the web tensile stress value and/or the web
tension value.
[0029] The smoothing functions G1 and G2, which smooth the motor
torque M.sub.MOT or the web tensile stress value and/or the web
tension value X.sub.RW of the reel changer, are filter functions.
The smoothing functions G1 and G2 are preferably dispensed with if
quantities that are already suitably smoothed are being supplied by
the torque sensor 25 and/or reel changer.
[0030] As has already been noted, the quantities c, m, and a are
constants. The quantities c and m are the constants of the
speed-dependent, linearized friction torque M.sub.REIB.
[0031] The constant a is a conversion factor, which is dependent on
a speed ratio i between the drive 16 and roll 17 of the feed
mechanism 15 and on the radius r of the roll 17. The conversion
factor is defined as follows:
a = i r ##EQU00001##
[0032] Instead of the model 24 illustrated in FIG. 4 for computing
the actual value X.sub.IST for the web tensile stress and/or the
web tension, the simplified model 24' shown in FIG. 3 can also be
used. In the model 24', a constant friction torque M.sub.REIB=c is
used for computing the actual value X.sub.IST of the web tensile
stress and/or the web tension, so that the speed N.sub.IST of the
drive 16 is not needed as an input variable for the model 24'. The
model 24' according to FIG. 3 then determines the actual value
X.sub.IST of the web tensile stress and/or the web tension as
follows:
X.sub.IST=G2 X.sub.RW+a*[G1(M.sub.MOT)+c]
where
[0033] X.sub.IST is the computed actual value of the web tensile
stress and/or the web tension,
[0034] X.sub.RW is the value of the web tensile stress and/or the
value of the web tension of the reel changer,
[0035] M.sub.MOT is the motor torque of the drive,
[0036] G1 and G2 are a smoothing functions, (which can be equal to
1 when the smoothing function is not required) and
[0037] a and c are constants.
[0038] As described above with reference to FIG. 2, in the
preferred embodiment, automatic control of the web tensile stress
and/or the web tension is superimposed on the automatic speed
control of the drive 16. In one embodiment, the automatic control
of the web tensile stress and/or the web tension is superimposed on
automatic control of a state of the drive 16 of the feed mechanism
15, in which case the control system 23 for the web tensile stress
and/or the web tension then outputs an offset for the setpoint
value of the state of the drive 16 as a correcting variable. In
this embodiment, the control system 23 can also adjust a
transmission or scaling factor.
[0039] In one embodiment of models 24 and 24' according to FIG. 4
and FIG. 3, respectively, a moment of inertia of the feed mechanism
is considered as a further input variable in order to improve the
computation of the actual value X.sub.IST of the web tensile stress
and/or the web tension when changes in the speed occur.
[0040] According to FIG. 2, in the preferred embodiment, the
control system 23 for the web tensile stress and/or the web tension
and the model 24 for mathematically determining the actual value
X.sub.IST of the web tensile stress and/or the web tension are
integrated in the drive controller 20. However, it is also possible
to realize these units as a separate system outside the drive
controller 20.
[0041] The constants a, c, and possibly m of the models 24 and 24'
are determined manually or by automated means. In the case of
automated determination of the parameters, a device for measuring
the web tension is installed between the feed mechanism 15 and the
printing unit 10 for determining the parameters, and in this case,
the drive controller 20 is operated with different setpoint values
for the web tensile stress at different speeds. In this connection,
the torque of the drive or the current of the drive that creates
the torque, the speed of the drive, and the web tension are
determined by measurement, and the parameters c, m, and a are
computed from these measured determinations by numerical
optimization. The parameters determined in this way are then used
in the model in order to mathematically determine the actual value
X.sub.IST for the web tensile stress and/or the web tension later
in the operation without a measuring device for the web tensile
stress.
[0042] Thus, while there have shown and described and pointed out
fundamental novel features of the invention as applied to a
preferred embodiment thereof, it will be understood that various
omissions and substitutions and changes in the form and details of
the devices illustrated, and in their operation, may be made by
those skilled in the art without departing from the spirit of the
invention. For example, it is expressly intended that all
combinations of those elements and/or method steps which perform
substantially the same function in substantially the same way to
achieve the same results are within the scope of the invention.
Moreover, it should be recognized that structures and/or elements
and/or method steps shown and/or described in connection with any
disclosed form or embodiment of the invention may be incorporated
in any other disclosed or described or suggested form or embodiment
as a general matter of design choice. It is the intention,
therefore, to be limited only as indicated by the scope of the
claims appended hereto.
* * * * *