METHOD AND APPARATUS FOR TRANSFERRING A TAPE BY SPOOLING

METHODE ET DISPOSITIF DE TRANSFERT D'UNE BANDE PAR BOBINAGE

English Abstract

A method and apparatus for transferring a tape by spooling is
disclosed. A tape is transferred by spooling from a first, unwinding spool
onto a second, winding spool, both spools being driven via a drive as a
function of a predefined tape tension and/or a predefined tape setpoint
speed at a setpoint rotational speed and/or with a setpoint torque. The
respective setpoint rotational speed and/or the respective setpoint torque
being determined as a function of a geometrical mean of the winding
circumferences of the two spools. The geometrical mean of the winding
circumferences of the two spools is determined continuously during transfer
by spooling.

Claims

What Is Claimed Is:
1. A method for transferring a tape by spooling from a first, unwinding
spool (11) onto a second, winding spool (13), wherein both spools are driven
via a respective drive as a function of a predefined tape tension and/or a
predefined tape setpoint speed at a setpoint rotational speed and/or with a
setpoint torque, and the respective setpoint rotational speed and/or the
respective setpoint torque being determined as a function of a geometrical
mean (UMG) of a winding circumference of each of the two spools, wherein
the geometrical mean (UMG) of the winding circumferences of the two
spools is determined continuously during transfer by spooling.
2. The method according to Claim 1, wherein, in order to determine the
geometrical mean (UMG) of the winding circumferences of the two spools, a
starting radius (r13, START) of the winding spool is predefined and/or
measured, and wherein actual rotational speeds (N11, N13) of the two spools
(11, 13) are measured, and wherein the geometrical mean (UMG) of the
winding circumferences of the two spools (11, 13) is calculated using the
following equations:
<IMG>

3. The method according to Claim 1, wherein, in order to determine the
geometrical mean (UMG) of the winding circumferences of the two spools
(11, 13), a starting radius (r11, START) of the unwinding spool (11) is
predefined and/or measured, and wherein actual rotational speeds (N11,
N13) of the two spools (11, 13) are measured, and wherein the geometrical
mean (UMG) of the winding circumferences of the two spools (11, 13) is
calculated using the following equations:
<IMG>
4. The method according to Claim 2, wherein the starting radius (r13,
START) of the winding spool (13) is predefined.
5. The method according to Claim 3, wherein the starting radius (r11,
START) of the unwinding spool (11) is predefined.
6. The method according to Claim 2, wherein a tape speed (V BAND) is
measured in order to measure the starting radius (r13, START) of the winding
spool (13), and wherein the starting radius (r13, START) is calculated using
the
following equation:
<IMG>
11

7. The method according to Claim 5, wherein a rotational speed (N23) of
a tape-guiding roller (23) is measured in order to measure a tape speed
(V BAND), and wherein the tape speed (V BAND) is calculated, with
specification
of a radius (r23) of the tape-guiding roller (23), using the following
equation:
v BAND = 2*.pi.*N23 *r23.
8. The method according to Claim 2, wherein a tape length (L BAND)
which has been transferred by spooling since a start of a transfer is
measured in order to measure the starting radius (r13, START) of the winding
spool (13), and wherein the starting radius (r13, START) is calculated using
the
following equation:
<IMG>
9. The method according to Claim 7, wherein the rotational speed (N23)
of the tape-guiding roller (23) is measured in order to measure a tape length
(L BAND) which has been transferred by spooling since a start of a transfer,
and wherein the tape length (L BAND) which has been transferred by spooling
is calculated, with specification of the radius (r23) of the tape-guiding
roller
(23), using the following equation:
<IMG>.
10. The method according to any one of Claims 1 to 8, wherein the
setpoint rotational speeds (N SOLL) of the spools (11, 13) are calculated from
the predefined tape setpoint speed (V BAND, SOLL) using the following
equation:
<IMG>
12

11. The method according to any one of Claims 1 to 9, wherein the
setpoint torques (M SOLL) of the spools (11, 13) are calculated from the
predefined tape tension (F BAND, SOLL) using the following equation:
<IMG>.
12. The method according to any one of Claims 1 to 10, wherein a
changing speed of rotational-speed ratios of the two spools (11, 13) is
determined as follows:
<IMG>
13. An apparatus for transferring a tape by spooling from a first,
unwinding spool (11) onto a second, winding spool (13), comprising a control
or regulating device for carrying out the method according to any one of
Claims 1 to 11.
14. A method for transferring a tape by spooling from a first, unwinding
spool onto a second, winding spool, comprising the steps of:
driving the first and second spools by first and second drives,
respectively, at a respective setpoint value, wherein the first and second
spools have a respective winding circumference during a transfer process;
wherein the respective setpoint value for each spool is determined as
a function of a geometrical mean of the winding circumferences and
wherein the geometrical mean is determined continuously during the
transfer process.
15. The method according to Claim 14, wherein the setpoint value is a
rotational speed.
13

16. The method according to Claim 14, wherein the setpoint value is a
torque.
17. An apparatus for transferring a tape, comprising:
a first unwinding spool having a continuously changing tape winding
circumference during a tape transfer process;
a second winding spool having a continuously changing tape winding
circumference during the tape transfer process; and
a control device coupled to the first and second spools;
wherein the control device provides a respective setpoint value to the
first and second spools for driving the first and second spools during the
tape transfer process and wherein the respective setpoint value for each
spool is determined by the control device as a function of a geometrical
mean of the tape winding circumferences of the first and second spools, and
further wherein the geometrical mean is determined continuously during
the transfer process.
18. The apparatus according to Claim 17, wherein the setpoint value is a
rotational speed.
19. The apparatus according to Claim 17, wherein the setpoint value is a
torque.
20. The apparatus according to Claim 17, wherein the respective setpoint
values are a function of a predefined tape setpoint value.
14

Description

CA 02548069 2006-05-25
METHOD AND APPARATUS FOR TRANSFERRING
A TAPE BY SPOOLING
BACKGROUND AND SUMMARY OF THE INVENTION
The invention relates to a method for transferring a tape by spooling.
Furthermore, the invention relates to an apparatus for transferring a tape
by spooling.
During transfer of tapes by spooling, the object is often set of
regulating or controlling the tape speed and the tape tension to a defined
value. A setpoint rotational speed or a setpoint torque for the
corresponding drives cannot be stipulated, however, as they change during
the spooling process or transfer process of the tape on account of the
changing diameters of the spools.
German Patent Document No. DE 44 27 780 C2 discloses a method
for transferring a tape by spooling from a first, unwinding spool onto a
second, winding spool, both spools being driven via in each case a drive as a
function of a predefined tape tension and a predefined tape setpoint speed
at a setpoint rotational speed and/or with a setpoint torque. According to
DE 44 27 780 C2, the respective setpoint rotational speeds and the
respective setpoint torques are determined as a function of a
mathematical/geometrical mean of the winding circumferences of the two
spools, it being presumed that the geometrical mean of the winding
circumferences is constant. In order to determine the geometric mean of
the winding circumferences, it is proposed according to DE 44, 27 780 C2 to
measure the current radii of the two spools once and to calculate the
geometrical mean of the winding circumferences therefrom. This has the
disadvantage that the current radii of both spools have to be measured. As
an alternative, DE 44 27 780 C2 proposes determining the geometrical
mean of the winding circumferences before the start of the transfer by
spooling using the known starting radius of a spool and the rotational-speed
ratio of the spools which is measured during starting. Here, the
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CA 02548069 2006-05-25
measurement has to take place within a short time period, so that an
inaccurate result can occur. Both variants have the disadvantage that a
constant geometrical mean of the winding circumferences is presumed and
therefore varying tape parameters in thickness and length which can occur
during transfer by spooling or during a tape change cannot be allowed for.
Proceeding from this, the present invention is based on the problem
of providing a novel method for transferring a tape by spooling and a
corresponding apparatus.
This problem is solved by a method and apparatus for transferring a
tape by spooling. According to the invention, the geometrical mean of the
winding circumferences of the two spools is determined continuously during
transfer by spooling.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred developments of the invention result from the following
description. One exemplary embodiment of the invention is explained in
greater detail using the drawing, without being restricted thereto. In the
drawing:
Fig. 1 shows an apparatus for transferring a tape by spooling, in
order to clarify the method according to the invention.
DETAILED DESCRIPTION OF THE DRAWINGS
In the following text, the present invention will be described in
greater detail with reference to Fig. 1.
Fig. 1 shows an apparatus 10 for transferring a tape 12 which is
wound on a first spool 11 by spooling onto a second spool 13. The first spool
11 is also called an unwinding spool and the second spool 13 is also called a
winding spool. Both spools 11 and 13 are usually connected in each case via
2

CA 02548069 2006-05-25
a shaft 14 and 15, respectively, to a motor 16 and 17, respectively, which
drives the former. The rotational speeds of the motors 16 and 17 and
therefore the rotational speeds of the spools 11 and 13 can be determined
with the aid of sensors 18 and 19. The sensors 18, 19 can be configured as
encoders. Instead of encoders, other sensors can also be used, for example
tachometers, magnetic rotary encoders or else rotary encoders based on
eddy current. According to Fig. 1, a rotational speed Nll of the first,
unwinding spool 11 can be measured with the sensor 18 and a rotational
speed Nls of the second, winding spool 13 can be measured with the sensor
19.
The first, unwinding spool 11 is characterized by a plurality of radii,
namely by what is known as an empty radius rli, what is known as a
starting radius rl, START and what is known as a current radius Rll. The
second, winding spool 13 is likewise characterized by a plurality of radii,
namely by what is known as an empty radius rls, a starting radius ris, sTaRT
and a current radius Ris. The starting radii rli, sTaR,T and ris, sTaR,T are
the
radii of the spools 11, 13 which are present at the start of the transfer by
spooling. The current radii Rii and Ria are radii of the spools 11, 13 which
change during transfer by spooling. When the entire tape length is wound
onto one of the spools 11 or 13, the latter then assumes the radius rli, VOLL
or ris, voLL, respectively, whereas the respective other spool 13 or 11 then
assumes the empty radius ri3 or rl, respectively.
It is to be noted here that, apart from the exemplary embodiment
described, it goes without saying that contactless sensing of the rotational
speeds of the spools can take place within the context of the invention. The
correlation of the motors and coils then takes place via corresponding
transmission ratios, and the rotational-speed sensors can then also be
arranged, for example, on the coils.
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CA 02548069 2006-05-25
If the tape 12 is transferred by spooling only in one direction, the
motor 16 or 17 of the unwinding shaft 14 or 15, respectively, can also be
used as a brake.
In the context of the present invention, with the aid of the apparatus
10 which is shown in Fig. 1, the tape 12 which is wound on the first,
unwinding spool 11 is then to be transferred by spooling onto the second,
winding spool 13, a control or regulating device 20 generating setpoint
rotational speeds and/or setpoint torques as actuating variables 21, 22 for
the drives 16, 17 of the spools 11, 13 as a function of the measured
rotational speeds Nm and Nls of the spools 11 and 13 and as a function of a
predefined tape setpoint speed VBArrD, soLL and/or a predefined tape tension
FBArrn, soLL.
Here, in the context of the present invention, the setpoint rotational
speeds and/or setpoint torques are generated as a function of a
mathematical/geometrical mean UMG of the winding circumferences of the
two spools 11 and 13, the geometrical mean UMG of the winding
circumferences being determined or calculated continuously during the
transfer by spooling, within the context of the present invention. The
following is true for the mathematical/geometrical mean UMG of the
winding circumferences:
UMG=2*~* R"+R,3
For the continuous determination of the geometrical mean UMG of
the winding circumferences of the two spools 11, 13, the knowledge and/or
measurement of the starting radius ris, sTaR.T of the winding spool 13 or the
starting radius rm, sTAit.T of the unwinding spool 11 is required in addition
to
the measurement of the rotational speeds Nll, Nis of the spools 11, 13.
Using the following equations, the geometrical mean UMG of the winding
circumferences of the two spools 11, 13 can be calculated from these
variables, Ull and Uls being calculated revolutions of the drives 16, 17 since
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CA 02548069 2006-05-25
the start or beginning of the transfer by spooling at the instant to, and xwa
representing the current rotational-speed ratio of the winding spool 13 with
respect to the unwinding spool 11.
r
Ul1 = jNl1 (t)dt
fo
f
U13 = f N13 (t)dt
fo
N13 (t)
xwa =
Nl l (t)
UMG=2*~*r .*(UZ+UZ)* ~'a2+1
l3,STAR7 13 11 U i - U 3 + 2 * ~YV a * UI 1 * U13 ) 2
UMG=2*~*r *(UZ +UZ)* ~'a2+1
11,START 13 11 Uj -~3+2*.xWa*Ull*U13)z
The starting radii rla,, START and ra,s, START can be converted into one
another as follows (the calculation of the current radii can be represented in
each case by corresponding transformation):
_ 2*Ull*U13+xwa*(U; -U;)
rlI,START - rl3,START * * * 2 2
2 xYVa UI 1 U13 + Ui l - U13
As has already been mentioned, the starting radius ris, START of the
winding spool 13 or the starting radius r>,>, START Of the unwinding spool 11
is required in order to calculate the geometrical mean UMG of the winding
circumferences of the two spools 11, 13. This starting radius ris, START of
the
winding spool 13 or the starting radius rl>, sTAFtT of the unwinding spool 11
can either be predefined or determined by measurement during the transfer
by spooling.
During the determination or calculation of the starting radius rls,
START Of the winding spool 13, a measured tape speed Vs~rrD is used which is
measured in the exemplary embodiment on a tape-guiding roller 23 with
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CA 02548069 2006-05-25
the aid of a sensor 24. It goes without saying that other measuring
methods of the tape speed are conceivable which are carried out, for
example, in a contactless or optical manner. The sensor 24 supplies the
control or regulating device 20 with a rotational speed N23 of the tape-
s guiding roller 23, from which the tape speed VB~rD of the tape 12 which is
to be transferred by spooling and therefore the starting radius rls, START Of
the winding spool 13 can be calculated, with specification of a radius rzs of
the tape-guiding roller 23, using the two following equations:
_ ~Na *\UI -U3)+2*U11 *U13 *N13)
rl3,START - vBAND * 2 2
2*~*N11*N13* U11+U13
vBAND =2*~*N23 *r23
As an alternative, the measurement of the starting radius ris, START Of
the winding spool can be determined on the basis of a tape length LsArtD
which has been transferred by spooling since the start of the transfer by
spooling at the instant to, it being possible for the tape length LBArtn which
has been transferred by spooling since the start of the transfer by spooling
to be calculated from the integral of the tape running speed VB~D.
According to this alternative, the starting radius ris, START Of the winding
spool 13 is then calculated using the two following equations:
U1 ~ - U 3 + 2 * xwa * U11 * U13
rl3,sTARr = LBAND * 2 * ~ * U,1 * U13 * ~U 11 + U13 * xwa~
r r
LBAND - JvBAND ~t)dt = 2 * ~ * r23 * f Nz3 (t)dt
to to
With the aid of the geometric mean UMG of the winding
circumferences of the spools 11, 13 which is determined continuously in the
abovementioned manner, the setpoint rotational speeds NsoLL and/or
setpoint torques MsoLL for the drives 16, 17 can then be determined using
the two following equations, the setpoint rotational speeds and setpoint
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CA 02548069 2006-05-25
torques which are determined by the control or regulating device 20 being
supplied to the drives 16, 17 as actuating variables 21 and 22, respectively:
yBAND,SOLL * 1 + xwa z
soLL = UMG
_ FBAND,SOLL * UMG
MSOLL -
1 z
2*~c* 1+~
xwa
In the context of the present invention, further variables can be
calculated; for example, the radius rll, voLL of the unwinding spool 11 using
the following equation, the spool 11 assuming the radius rll, voLL when the
entire tape 12 is wound completely onto the spool 11:
UMG z z
r»,voLL = 4*~2 -ris
y, r~3,sraRr *~U i +U~s~ *~xwaz +1)-rz
a,voLL = ~Ul - U 3 + 2 * xwa * Ul ~ * U13 )z
Furthermore, an overall winding cross-sectional area can be
calculated from the two winding cross-sectional areas All, Als of the spools
11, 13 with the following equation:
UMGz
A" +A,3 = 4*~c
Moreover, in the context of the present invention, a tape thickness D
of the tape 12 which is to be transferred by spooling can be determined with
the following equation:
U13 -xWCI*U~1
D=2*rl3,START* U~ -U3+2*xwa*U"*U,3
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CA 02548069 2006-05-25
Depending on the tape width, it is to be taken into consideration here
that the thickness D which is calculated with the aid of the above equation
can include any air inclusions between the individual winding layers. If the
real nominal tape thickness is known or can be measured, the thickness of
the air inclusions or their change in thickness can be determined with the
method according to the invention as a consequence of the spooling transfer
process.
The overall tape length LBArrn, cESAMT can likewise be calculated with
the method according to the invention, to be precise on the basis of the
following equation:
r 2 _ 2
_ * ~rII,~OLL rll
1'BAND,GESAMT - ~
Here, the free travel length of the tape 12 between the two spools 11
and 13 is to be added to the value which is determined with the aid of the
above equation.
Furthermore, a changing speed of the rotational-speed ratios of the
two spools 11 and 13 can be determined as follows:
dxwa -2* Nli +N3~*~Un *N13 -U13 *Nll~
2 * 2 2
dt NI1 U11 + U13
With the aid of the method according to the invention for transferring
a tape by spooling between two spools, it is proposed for the first time to
determine the mathematical/geometrical mean UMG continuously which is
required to determine the setpoint rotational speeds and setpoint torques
for the drives of the two spools. As a result, varying tape parameters in
thickness and length which can occur during transfer by winding or during
a tape change can be allowed for.
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CA 02548069 2006-05-25
List of Designations:
Apparatus
11 Spool
12 Tape
5 13 Spool
14 Shaft
Shaft
16 Drive
17 Drive
10 18 Sensor
19 Sensor
Control and regulating device
21 Actuating signal
22 Actuating signal
15 23 Tape-guiding roller
24 Sensor
The foregoing disclosure has been set forth merely to illustrate the
invention and is not intended to be limiting. Since modifications of the
disclosed embodiments incorporating the spirit and substance of the
20 invention may occur to persons skilled in the art, the invention should be
construed to include everything within the scope of the appended claims
and equivalents thereof.
9

Representative Drawing