U.S. patent application number 13/174212 was filed with the patent office on 2011-10-20 for research press.
Invention is credited to Allan Michael Burwinkel, Larry Ray Gilliam, JR., Richard William Hamm, Richard Allan Roth, II, Stuart James Shelley.
Application Number | 20110252901 13/174212 |
Document ID | / |
Family ID | 40510431 |
Filed Date | 2011-10-20 |
United States Patent
Application |
20110252901 |
Kind Code |
A1 |
Shelley; Stuart James ; et
al. |
October 20, 2011 |
Research Press
Abstract
A method of simulating loading of an area on a workpiece in a
production line type process. Also, a simulation press having a
main body and an actuator attached thereto. The actuator is
substantially aligned with the main body. A first plate is coupled
to the main body and a second plate is coupled to the actuator.
Both plates are adapted to engage a workpiece so as to simulate
various modes of deformation of an area or areas on the workpiece
when the second plate is moved relative to the first plate. The
simulation press further includes a drive controller for
controlling operation of the actuator. The drive controller
additionally responds to feedback from at least one feedback sensor
included with the simulation press.
Inventors: |
Shelley; Stuart James;
(Cincinnati, OH) ; Roth, II; Richard Allan; (Blue
Ash, OH) ; Burwinkel; Allan Michael; (Cincinnati,
OH) ; Hamm; Richard William; (Loveland, OH) ;
Gilliam, JR.; Larry Ray; (Sparta, KY) |
Family ID: |
40510431 |
Appl. No.: |
13/174212 |
Filed: |
June 30, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11937034 |
Nov 8, 2007 |
7992612 |
|
|
13174212 |
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Current U.S.
Class: |
73/866.4 |
Current CPC
Class: |
G01N 2203/0282 20130101;
G01N 3/08 20130101; G01N 2203/0019 20130101; B30B 15/0094
20130101 |
Class at
Publication: |
73/866.4 |
International
Class: |
G01D 21/00 20060101
G01D021/00 |
Claims
1. A method of simulating loading of an area on a workpiece in a
production line type process comprising the steps: providing a
workpiece comprising at least one layer; providing a first plate
having a first surface, the first plate being operably coupled to a
base; providing a second plate having a second surface, the second
plate being operably coupled to an armature of an actuator, the
actuator being further coupled to the base such that the direction
of movement of the armature of the actuator is substantially
axially aligned with a longitudinal axis of symmetry of the base
and generally lies in the same plane as the base; and moving one of
the first and second plates relative to the other of the first and
second plates such that the first and second surfaces compress a
point site on the workpiece so as to simulate compression loading
of a point site on a workpiece in a production line type
process.
2. The method of simulating loading of an area on a workpiece in a
production line type process as set forth in claim 1, further
including active gap control comprising providing one or more
sensors comprising at least one of: at least one sensor for
measuring the gap between the first plate and the second plate; at
least one sensor for measuring the load of at least one of the
first and second plates; and at least one sensor for measuring the
inertial force of at least one of the first and second plates;
wherein the one or more sensors provide feedback for determining
accurate gap measurement of a gap between the first and second
plates.
3. The method of simulating loading of an area on a workpiece in a
production line type process as set forth in claim 1, wherein the
first surface of the first plate comprises one of a substantially
planar surface for simulating an anvil roll and at least one
protuberance for simulating a production line type process and the
second surface of the second plate comprises one of a substantially
planar surface for simulating an anvil roll and at least one
protuberance for simulating a production line type process.
4. The method of simulating loading of an area on a workpiece in a
production line type process as set forth in claim 1, further
comprising: determining a motion trajectory profile for one of the
first and second plates based on a desired loading gap profile
between the first and second plates; generally measuring an actual
gap profile between the first and second plates during loading;
determining a second motion trajectory profile based on the desired
loading gap profile and the actual gap profile.
5. The method of simulating loading of an area on a workpiece in a
production line type process as set forth in claim 4, wherein
determining the second motion trajectory profile comprises
determining a motion trajectory profile error based on the desired
loading gap profile and the actual gap profile and the motion
trajectory profile error is the difference of the desired loading
gap profile and the actual gap profile.
6. The method of simulating loading of an area on a workpiece in a
production line type process as set forth in claim 5, wherein the
second motion trajectory profile is determined based on at least a
portion of the total value of the profile error.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional of U.S. application Ser.
No. 11/937,034 filed Nov. 8, 2007.
FIELD OF THE INVENTION
[0002] The present invention relates to an apparatus and method for
simulating a production line process, and more particularly to an
apparatus and method for simulating various modes of deformation of
an area or areas on a workpiece in a nip type process. The present
invention also relates to an apparatus and method for a variety of
fundamental material testing applications/modes including, but not
limited to, simple compression, planar, simple shear, oscillatory
viscoelasticity, etc.
BACKGROUND OF THE INVENTION
[0003] A variety of processes are used on production lines.
Examples, include compression loading, such as fusion bonding
processes, which may be performed on a plurality of point sites of,
or discrete locations on, a workpiece/web material in a nip type
process. See, for example, U.S. Pat. Nos. 4,854,984 and 4,919,738.
A fusion bonding process, for example, may involve passing a
workpiece, such as a thermoplastic dual-layer web material, through
a nip defined by two rolls, wherein one roll is provided with a
plurality of protuberances. By compressing the workpiece/web
material at point sites between the rolls via the protuberances,
friction bonds may be effected at those sites. That is, the
material at each point site is caused to flow or melt. If the
workpiece/web material comprises two or more layers, those layers
may be caused to bond to one another at each site. In a
production-type process, however, the precise load and gap that the
workpiece/web material experiences typically cannot be accurately
measured for several reasons, including but not limited to accuracy
limits on pressure gauges, the inclusion of equipment inertial
loads, vibrations of the equipment and the effect of those
vibrations on the gap at the nip point, etc.
[0004] It would be desirable to have a press that can simulate
processes at speeds that are in-line with current and actual
production process speeds. It also would be desirable to have a
press that can accurately measure what a workpiece or web material
experiences during various production processes.
BRIEF SUMMARY OF THE INVENTION
[0005] The present invention, in one embodiment, is a simulation
press comprising a main body having an actuator attached thereto
such that the actuator is substantially axially aligned with a
longitudinal axis of symmetry of the main body. The actuator has a
moving face which moves generally in a straight line along the
longitudinal axis of symmetry of the main body in the same plane as
the main body. A first plate is operably coupled to the main body.
The first plate is adapted to engage a workpiece. A second plate is
operably coupled to the actuator for movement with a moving face of
the actuator. The second plate is adapted to engage the workpiece.
The press also includes a drive controller coupled to the actuator
for controlling the operation of the actuator in response to
feedback from at least one feedback sensor so as to cause the
second plate to move relative to the first plate such that the
first and second plates engage at least one point site on the
workpiece.
[0006] The present invention, in another embodiment, is a method of
simulating loading of an area on a workpiece in a production line
type process including the steps of providing a workpiece
comprising at least one layer; providing a first plate having a
first surface, the first plate being operably coupled to a base;
providing a second plate having a second surface, the second plate
being operably coupled to an armature of an actuator, the actuator
being further coupled to the base such that the direction of
movement of the armature of the actuator is substantially axially
aligned with a longitudinal axis of symmetry of the base and
generally lies in the same plane as the base; and moving one of the
first and second plates relative to the other of the first and
second plates such that the first and second surfaces compress a
point site on the workpiece so as to simulate compression loading
of a point site on a workpiece in a production line type
process.
[0007] While multiple embodiments are disclosed, still other
embodiments of the present invention will become apparent to those
skilled in the art from the following detailed description, which
shows and describes illustrative embodiments of the invention. As
will be realized, the invention is capable of modifications in
various obvious aspects, all without departing from the spirit and
scope of the present invention. Accordingly, the drawings and
detailed description are to be regarded as illustrative in nature
and not restrictive.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] While the specification concludes with claims particularly
pointing out and distinctly claiming the subject matter that is
regarded as forming the present invention, it is believed that the
invention will be better understood from the following description
taken in conjunction with the accompanying Figures, in which:
[0009] FIG. 1 is a schematic view of first and second rolls
effecting a nip type process.
[0010] FIG. 2A is a schematic view of multiaxial loading using a
press in accordance with an embodiment of the present
invention.
[0011] FIG. 2B is a schematic view of multiaxial loading using a
press in accordance with an embodiment of the present
invention.
[0012] FIG. 2C is a schematic view of multiaxial loading using a
press in accordance with an embodiment of the present
invention.
[0013] FIG. 3A is a schematic view of a shearing simulation using a
press in accordance with an embodiment of the present
invention.
[0014] FIG. 3B is a schematic view of tensile loading using a press
in accordance with an embodiment of the present invention.
[0015] FIG. 3C is a schematic view of a bending simulation using a
press in accordance with an embodiment of the present
invention.
[0016] FIG. 4A is a graph of an engagement profile for a press in
accordance with an embodiment of the present invention.
[0017] FIG. 4B is a graph of an engagement profile for a press in
accordance with an embodiment of the present invention.
[0018] FIG. 4C is a graph of an engagement profile for a press in
accordance with an embodiment of the present invention.
[0019] FIG. 5A is a perspective view of a press in accordance with
an embodiment of the present invention.
[0020] FIG. 5B is a side view of a press in accordance with an
embodiment of the present invention.
[0021] FIG. 5C is a top view of a press in accordance with an
embodiment of the present invention.
[0022] FIG. 6 is an exploded schematic view of a press in
accordance with an embodiment of the present invention.
[0023] FIG. 7 is perspective view of pedestals of a press in
accordance with an embodiment of the present invention.
[0024] FIG. 8 is a perspective view of a base of a press in
accordance with an embodiment of the present invention.
[0025] FIG. 9 is a perspective view of a back actuator support of a
press in accordance with an embodiment of the present
invention.
[0026] FIG. 10 is a perspective view of simulation components of a
press in accordance with an embodiment of the present
invention.
[0027] FIG. 11A is an exploded view of a moving plate assembly of a
press in accordance with an embodiment of the present
invention.
[0028] FIG. 11B is a perspective view of a moving plate assembly of
a press as shown in FIG. 11A.
[0029] FIG. 12A is an exploded view of a backplate assembly of a
press in accordance with an embodiment of the present
invention.
[0030] FIG. 12B is a perspective view of a backplate assembly of a
press in as shown in FIG. 12A.
[0031] FIG. 13 is a perspective view of a material holder of a
press in accordance with an embodiment of the present
invention.
[0032] FIG. 14 is a perspective view of simulation components of a
press in accordance with an embodiment of the present
invention.
[0033] FIG. 15 is a perspective view of a safety release plate and
backplate air bag of a press in accordance with an embodiment of
the present invention.
[0034] FIG. 16A is a side view of an embodiment of tooling plates
of a press in accordance with an embodiment of the present
invention during engagement of a fusion or bonding type
operation.
[0035] FIG. 16B is a side view of an embodiment of tooling plates
of an embodiment of a press in accordance with an embodiment of the
present invention during engagement of a fusion or bonding type
operation.
[0036] FIG. 17A is a side view of another embodiment of tooling
plates of a press in accordance with an embodiment of the present
invention during engagement of an activation type operation.
[0037] FIG. 17B is a side view of another embodiment of tooling
plates of a press in accordance with an embodiment of the present
invention during engagement of an activation type operation.
[0038] FIG. 18 is a graph of the trajectory motion profile for a
press in accordance with an embodiment of the present
invention.
[0039] FIG. 19 is a graph of the variation in maximum velocity
achieved in an approach profile as a function of the approach time
for a press in accordance with an embodiment of the present
invention.
[0040] FIG. 20 is the resulting displacement, velocity, and
acceleration curves for an approach profile for a press in
accordance with an embodiment of the present invention.
[0041] FIG. 21 is the resulting displacement, velocity, and
acceleration curves for a complete trajectory motion profile for a
press in accordance with an embodiment of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0042] The present invention is a novel and advantageous press for
simulating manipulation of a workpiece or web material during a
production line process or during various other deformation
processes or testing of the workpiece's mechanical response. Any of
a variety of production line processes can be simulated with the
invention described herein, including but not limited to
compression loading on a point site of a workpiece/web material.
Simulated compression loading can include, but is not limited to,
that effected by fusion bonding rolls. As shown in FIG. 1, a fusion
bonding process and system 10 may involve passing a workpiece W,
such as a thermoplastic dual-layer web material, through a nip N
defined by rolls 12 and 14, wherein the first roll 12 may be
provided with a plurality of protuberances 16. By compressing the
workpiece/web material at point sites W.sub.PS via the
protuberances 16, friction bonds may be effected at those sites.
That is, the material at each point site W.sub.PS may be caused to
flow or melt. If the workpiece/web material comprises two or more
layers, those layers can be caused to bond to one another at each
site. In some embodiments, it may not be desirable to cause the
material to flow or melt during the production line process. In
certain embodiments, operations other than compressing a point site
may be performed on a production line, such as but not limited to
stretching, cutting, perforating, etc. In certain embodiments, a
production line process may involve any roll speed, force, cut,
perforation, bond, etc. Example workpiece materials comprise
thermoplastic webs, films, fibrous or particulate agglomerations,
composites made of one or more of the preceding materials, etc.,
such as polyethylene webs, films, etc. These materials may comprise
one or more layers of any suitable thickness. For example, each
layer can be between about 0.05 mm and about 5 mm, between about
0.1 mm and about 10 mm, less than 0.05 mm, or greater than about 10
mm.
[0043] With reference again to FIG. 1, during one type of
production line process, such as a nip type process, a protuberance
16 and a corresponding section 14a of an engaging or second roll 14
may compress a point site W.sub.PS on a workpiece W a sufficient
amount, to a sufficient temperature, and at a sufficient speed, so
as to cause the material at the point site W.sub.PS to flow or melt
due to quasi-adiabatic inelastic heat generation. If the workpiece
W comprises two or more layers of material, those layers may be
bonded together. It is noted that during a fusion bonding
operation, the protuberance 16 and the corresponding section 14a
may be at a temperature substantially equal to ambient temperature
or heated to a temperature above ambient. In some embodiments, it
may not be desirable to cause the material to flow or melt. In
certain embodiments, other operations other than compressing a
point site may be simulated, such as but not limited to stretching,
cutting, perforating, etc. In certain embodiments, any roll speed,
force, cut, perforation, bond, etc. may be simulated using the
press of the present invention. For example, in some embodiments,
it may be desirable to test boundary conditions of a sample
workpiece processing method by simulating both ideal and non-ideal,
expected and unexpected, calculated and non-calculated, etc. roll
speeds, forces, cuts, perforations, bonds, etc. Additionally, in
some embodiments, it may be desirable to perform a variety of
material testing applications/modes including, but not limited to,
simple compression, planar, simple shear, oscillatory
viscoelasticity, etc. In certain embodiments, the invention
described herein may be used to simulate the shaking that a
workpiece may experience during a production line process, such as
folding.
[0044] In certain embodiments, the invention described herein may
be used to simulate combined multiaxial loading. Combined
multiaxial loading may be used to understand a material's yield
surface hardening behaviors as well as mimic production conditions.
In production environments, for example, sometimes one of the
roll's, e.g., roll 12 or 14, surface speed is slightly faster than
the mating roll. This differential surface speed could be simulated
by applying a representative speed during the press event by moving
either tooling plate (discussed in detail below) with respect to
the other tooling plate, perpendicular to the actuator's line of
action, as illustrated in FIG. 2A. In one embodiment, combined
loading including compression and transverse shearing through the
thickness of the material could be simulated by positioning the
tooling plates at an angle .alpha. with respect to the actuator's
line of action, as illustrated in FIG. 2B. In certain embodiments,
combined loading including compression and in-plane shearing could
be simulated by rotating either tooling plate with respect to the
other tooling plate, as illustrated in FIG. 2C. It is recognized
that other combined multiaxial loading simulations may be performed
using the various embodiments of the press described herein.
[0045] In certain embodiments, the present invention may be used to
measure and understand a material's mechanical response during
various processes, as well as measuring a material's constitutive
properties. This may allow links to be made between material
properties, process conditions, and product quality and
performance. The press of the present invention, for example, may
be used to simulate or test shearing, tensile loading, and bending,
as illustrated in FIGS. 3A, 3B, and 3C. Example test profiles for
example simulations, such as the above example simulations, are
illustrated in FIGS. 4A, 4B, and 4C. In one embodiment, tensile
loading may be realized on the press via activation. In certain
embodiments, as illustrated in FIG. 3B, tensile loading may be
implemented by causing the actuator to move away from the backplate
assembly (discussed in detail below) rather than toward it. In
certain embodiments, lab shear loading may be possible.
[0046] An embodiment of a press 20 in accordance with the present
invention is illustrated in FIGS. 5A through 5C. The press 20 may
generally comprise some or all of pedestals 36, a base 22, support
air bags 24, actuator 26, back actuator support 28, moving plate
assembly 30, backplate assembly 32, and backplate air bag 34. As
can be seen from FIGS. 5B and 5C, actuator 26 may be positioned
generally axially on a longitudinal axis of symmetry of base 22
(shown as dashed line `L`). Longitudinal axis L, in some
embodiments, may be located generally equidistant from a top and
bottom surface of base 22 and generally equidistant from side
surfaces of base 22. That is, longitudinal axis L may be located
generally along a central, longitudinal axis of symmetry of base
22. In other words, actuator 26 may be positioned generally in the
same plane as base 22. This may have the benefit that inertial
forces associated with acceleration of the armature of the actuator
26 may then generally not exert bending forces on base 22 and
excite out-of-plane vibration modes of base 22.
[0047] With reference to FIG. 6, an exploded view of a further
embodiment of a press 20 in accordance with the present invention
is illustrated. The press 20 may generally comprise some or all of
sole plates 40, pedestals 36, support air bags 24, top plates 44,
safety stops 42, base 22, trunion block support 72, actuator 26,
back actuator support 28, exhaust 62, moving plate assembly 30,
backplate assembly 32, upper girdle 116, linear bearings 122, inlet
areas 52, backblock 114, safety release plate 118, backplate air
bag 34, and drive controller 200. It is recognized that the
aforementioned elements do not form a list, partial or complete, of
required press components, nor do the aforementioned elements form
an exhaustive list of all the components that may be used in
accordance with the present invention. That is, several of the
components shown in FIG. 6 may be removed, or further components
may be included, to achieve an embodiment of a press 20 in
accordance with the present invention.
[0048] With regard to fastening, mounting, attaching, or connecting
the components of the press of the present invention to form the
system as a whole, unless specifically described otherwise, such
are intended to encompass fastening by any suitable method.
Examples of suitable fastening methods include the use of
conventional fasteners such as screws, nut and bolt connectors,
rivets, toggles, pins, and the like. Furthermore, components may
also be connected or coupled, where appropriate, by welding,
friction fitting, deformation, etc. Electrical components and
connections may be made using appropriate electrical components and
connection methods, including conventional components and
connectors. Measuring devices for measuring load, acceleration,
etc., may be selected from such measuring devices that are suitable
for use in the present invention. For example, devices such as
sensors, transducers, and the like may be selected from any such
measuring devices suitable for use in the present invention. Unless
otherwise specifically disclosed or taught, materials for making
components of the present invention may be selected from any
appropriate materials, which include but are not limited to
materials such as metal, metallic alloys, fibers, plastics,
ceramic, and the like, and any suitable combinations of these.
Similarly, any materials for making components of the present
invention may be manufactured by any appropriate manufacturing
and/or production methods including casting, extruding, molding,
and machining.
[0049] With reference to FIG. 7, an embodiment of press 20 may
include sole plates 40. Sole plates 40 optionally may be securely
attached to the ground by any suitable manner, including but not
limited to, bolting the sole plates 40 to the ground, welding the
sole plates 40 to the ground, etc. Alternatively, sole plates 40
need not be securely attached to the ground. Pedestals 36 may be
mounted on top of sole plates 40. Any means of mounting pedestals
36 to the sole plates 40 may be used to mount pedestals 36 to the
sole plates 40. In an embodiment shown in FIG. 7, pedestals 36 may
be mounted to sole plates 40 with bolts. Although there are four
pedestals 36 illustrated in FIG. 7, it is recognized that a fewer
or greater number of pedestals 36 may be used, as desired. It is
again recognized that all components of press 20 discussed in
detail may not be necessary. For example, sole plates 40 may be
excluded from some embodiments of press 20. Similarly, pedestals 36
may be excluded from some embodiments of press 20, for example
where press 20 may be suspended from a ceiling or other suitable
structure.
[0050] In some embodiments, support air bags 24 may be provided.
Support air bags 24 may be mounted as desired, including on top of
pedestals 36, and between pedestals 36 and base 22. In certain
embodiments, support air bags 24 may include a top plate 44 for
attaching base 22 to support air bags 24. In other embodiments, top
plate 44 may be excluded. In certain embodiments of press 20, it
may be desirable to isolate the base, and thus isolate the attached
parts, including the actuator 26, moving plate assembly 30, and
backplate assembly 32. Therefore, support air bags 24, in some
embodiments, may help isolate these components from the external
environment, e.g., external background vibrations, as the external
environment may taint any data obtained by the press 20. That is,
support air bags 24 may isolate base 22 and attached parts from,
for example, but not limited to, external vibrations and external
noise into the system. The support air bags 24 may also isolate the
external environment from vibrations caused by the press 20. It is
recognized that, in some embodiments, support air bags 24 need not
be provided.
[0051] Pedestals 36, in an embodiment, may further include safety
stops 42. Safety stops 42 may be securely mounted to the tops of
pedestals 36, near the support air bags 24, and slidably connect to
base 22. In alternate embodiments, safety stops 42 may be securely
mounted to base 22 and slidably connect to the tops of the
pedestals 36, near the support air bags 24. Safety stops 42 may
provide support to base 22 in the event a support air bag 24 fails.
In a further embodiment, safety stop 42 may maintain base 22 on a
pedestal 36 in the event a support air bag 24 fails. Similarly,
safety stops 42 may maintain base 22 on the pedestals 36 during
unexpected or accidental incidents, such as an earthquake or any
other incident where base 22 could otherwise fall off the
pedestals, such as the press 20 being accidentally struck by, for
example, a piece of machinery.
[0052] Referring to FIGS. 5A and 8, base 22 may be mounted,
including securely mounted, on top of support air bags 24, or more
particularly, top plates 44. Base 22, in an embodiment, may be
heavy and rigid, or stiff or inflexible, such that it has a high
inertia. In some embodiments, base 22 may be substantially heavy
and rigid. In certain embodiments, base 22 may be heavy and rigid
in comparison to some of the other components of press 20. For
example, base 22 may be about twice as heavy and/or rigid as some
of the other components of press 20, about three times as heavy
and/or rigid as some of the other components, about ten times as
heavy and/or rigid as some of the other components, or any other
suitable multiplicative nonzero value. As such, base 22 may provide
further isolation, for example, from external and internal
vibration, noise, etc. Similarly, base 22 may provide a stable
structure that does not bend easily nor is affected by inertial or
moment forces created by actuator 26 while press 20 is in
operation. In certain embodiments, other components of press 20 may
be as heavy and rigid as base 22. Base 22 may be any suitable
weight or rigidity. In an embodiment, base 22 may be manufactured
from steel, but it is recognized that base 22 could be manufactured
from any number of materials, such as but not limited to any metal,
plastic, graphite, etc., or any combination of materials. In a
further embodiment, base 22 may include inlet areas 52, which may
divide the open area into two sections, simulation area 54 and
backplate air bag area 56.
[0053] With reference now to FIGS. 5A, 9, and 10, back actuator
support 28 may be mounted to base 22 and actuator 26, such that
back actuator support 28 may be mounted between base 22 and
actuator 26. Back actuator support 28 may provide strength and
rigidity to actuator 26. Back actuator support 28, in an
embodiment, may include an exhaust 62, which may further be
connected to an exhaust system or fan to draw heat away from
actuator 26. It is recognized that back actuator support 28 may be
excluded in some embodiments of press 20.
[0054] As shown in FIG. 10, in an embodiment, actuator 26 may be
attached to base 22 using trunion block support 72. Actuator 26 may
comprise a housing and a forward moving face 112, as shown in FIG.
11A, on which moving plate assembly 30 may be attached. In a
further embodiment, actuator 26 may be a voice-coil type vibration
exciter, e.g., an electrodynamic shaker system. It is recognized,
however, that other suitable actuator systems, such as, but not
limited to, a slider crank mechanism, a linear motor, or
hydraulics, may be used in place of a voice-coil type vibration
exciter. Actuator 26, in an embodiment, may further be designed for
high bandwidth control. In certain embodiments, the armature
structure of actuator 26 may be designed not to have any structural
resonances within the bandwidth of the actuator control system and
data collection system.
[0055] Actuator 26 may further include a sensor, such as a linear
encoder or other suitable encoder, that measures the relative
position of the armature, e.g., forward moving face 112, of the
actuator relative to the housing of the actuator 26. The sensor, in
one embodiment, may be used for real-time position feedback control
during a cycle of the actuator 26.
[0056] As previously stated, actuator 26 may be positioned
generally axially on a longitudinal axis of symmetry of base 22.
The longitudinal axis, in some embodiments, may be located
generally equidistant from a top and bottom surface of base 22 and
generally equidistant from side surfaces of base 22. That is, the
longitudinal axis of symmetry may be located generally along a
central, longitudinal axis of base 22. In other words, actuator 26
may be positioned generally in the same plane as base 22.
[0057] Motion of certain portions of press 20 may cause errors in
the measured force and may also result in discrepancies in gap
measurement. Therefore, in some embodiments, actuator 26 may be
positioned generally axially on a longitudinal axis of symmetry of
base 22 such that the bending forces, e.g., inertial and/or moment
forces, have less effect on press 20 while press 20 is in operation
than would exist if actuator 26 were not positioned generally
axially on a longitudinal axis of symmetry of base 22. In some
embodiments, actuator 26 may be positioned generally axially on a
longitudinal axis of symmetry of base 22 such that no bending
forces of press 20 exist. Thus, in some embodiments, bending forces
of press 20 may be neglected during operation of press 20. That is,
bending forces of press 20 may be reduced or may not exist, and so
need not be considered, when determining the effects of a process
on a workpiece.
[0058] Reference now is made to FIGS. 10, 11A, and 11B. FIG. 11A
shows an exploded view of an embodiment of the components of moving
plate assembly 30, while FIG. 11B shows the components together.
Moving plate assembly 30 may include an insulating plate 90 mounted
to forward moving face 112 of actuator 26 and heating/cooling block
88, such that the insulating plate 90 is between forward moving
face 112 and heating/cooling block 88. Insulating plate 90 may
insulate actuator 26 from the varying temperatures of
heating/cooling block 88.
[0059] In some embodiments, the temperature of heating/cooling
block 88 and heating/cooling block 98 (see FIGS. 10, 12A, and 12B)
may be controlled, and in other embodiments they may be
independently controlled. In an embodiment, glycol lines may be
connected to heating/cooling block 88 to decrease the temperature
of heating/cooling block 88. Alternatively, liquids or refrigerants
other than glycol can be used. Similarly, it is recognized that any
suitable means of cooling heating/cooling block 88 may be used to
decrease the temperature of heating/cooling block 88, including but
not limited to air cooling by circulating air through
heating/cooling block 88, etc. In an embodiment, heating cartridges
may be placed in heating/cooling block 88 to increase the
temperature of heating/cooling block 88. Alternatively, it is
recognized that any suitable means of heating heating/cooling block
88 may be used to increase the temperature of heating/cooling block
88. Heating/cooling block 88 may further include temperature
sensors or thermocouples that measure the temperature of
heating/cooling block 88. Therefore, the temperature of
heating/cooling block 88 can be increased or decreased
automatically using drive controller 200 or an independent control
system to maintain a desired temperature throughout simulation.
[0060] Tooling plate 86 may be mounted to heating/cooling block 88.
Alternatively, tooling plate 86 may be integral with
heating/cooling block 88. Tooling plate 86 may provide the
simulated surface of one of the compression rolls 12 or 14 shown in
FIG. 1. Tooling plate 86, in one embodiment, may be interchangeable
and may be changed, as desired, to simulate different deformation
processes, such as activation, fusion bonding, embossing, crimping,
etc. FIGS. 11A and 11B illustrate tooling plate 86 as having a
substantially planar surface. Tooling plate 86 may, however,
include a protuberance, a pattern, a plurality of protuberances or
patterns, depressions, grooves, etc., or any other characteristic
that is desired for simulation. In an embodiment, tooling plate 86
includes a nub. A nub may be any desired size, including any
nonzero size, or from about 0.1 mm to about 50 mm or larger, or
from about 1 mm to about 10 mm, or about 2 mm, etc.
[0061] Moving plate assembly 30 may include target blocks 84
mounted to heating/cooling block 88. In an embodiment, target
plates 82 may be mounted to target blocks 84 for use in conjunction
with optical position sensors 92 of backplate assembly 32. Target
plates 82 may be reflecting mirrors. In embodiments, target plates
82 may be used in conjunction with capacitive position sensors
rather than optical position sensors 92. Alternatively, other types
of sensors may be used, such as, but not limited to, eddy current
sensors, etc. Target plates 82 and sensors 92 may measure the gap
between tooling plates 86 and 100. The sensors 92 may measure the
gap between tooling plates 86 and 100 during each cycle of actuator
26. The gap data may be used, in addition to generating material
stress-strain characteristics, to update the command given to the
real-time position control loop (which may use the linear encoder
for real-time position feedback) for the next cycle. The feedback
gap data from sensors 92 may be used to adjust the next cycle for
deviations between the gap measurement and the armature position
measured with the linear encoder.
[0062] As previously mentioned, it is recognized that not all
components described in detail need be provided with all
embodiments of press 20. For example, insulating plate 90,
heating/cooling block 88, glycol lines, heating cartridges, tooling
plate 86, target blocks 84, target plates 82, etc. may be excluded
or altered, and the resulting press will remain in accordance with
an embodiment of press 20 of the present invention.
[0063] Reference now is made to FIGS. 10, 12A, and 12B. FIG. 12A
shows an exploded view of an embodiment of the components of
backplate assembly 32. FIG. 12B shows the components together.
Backplate assembly 32 may include position sensors 92. As
previously discussed, position sensors 92 may be capacitive
sensors, optical sensors, eddy current sensors, etc. In an
embodiment as illustrated in FIGS. 12A and 12B, position sensors 92
may be optical sensors used in conjunction with target plates 82
(e.g., reflective mirrors) to measure the gap between tooling
plates 86 and 100.
[0064] Load cells 104 and accelerometers 102 may be mounted to
support block 94. Load cells 104 and accelerometers 102 may
contribute to active gap control. For example, in some embodiments,
gap measurement, the distance between tooling plate 86 and 100, may
not be compensated to calculate the actual gap simulated by press
20 by measuring the movement of backplate assembly 32 and
subtracting the movement from the gap measurement. In some
embodiments, under dynamic conditions, inertial accelerations and
forces may not be neglected. Load cells 104 may measure the
reaction force or support force applied to backplate assembly 32.
This reaction force is generally equal to the actual force applied
to the workpiece/web material only if there is no acceleration of
backplate assembly 32. If there is acceleration of the backplate
assembly 32, the reaction force measured by load cells 104 may
differ from the actual force applied to the workpiece/web material
by an amount equal to the inertial force causing the acceleration
of the backplate assembly 32. Accelerometers 102 may measure the
acceleration of backplate assembly 32. The inertial force may be
determined by multiplying the acceleration measured by
accelerometers 102 by the mass of backplate assembly 32. The actual
force applied to the workpiece/web material may be obtained by
adding the inertial force to the reaction force measured by load
cells 104.
[0065] Therefore, press 20 may be suitable for active gap control.
That is, press 20 may be used to measure the force applied to the
workpiece/web material in a manner that includes the forces
experienced by the workpiece/web material while the forces from
external loads, including but not limited to, inertial loads from
the equipment, vibration from sources external to the press, etc.
are filtered. In some embodiments, the dynamic gap, i.e., the gap
measured at any point in time during operation of press 20, may be
measured to a level of accuracy that is an order of magnitude
greater than gap values that may be experienced by workpiece/web
materials during the actual process that is being simulated by
press 20. For example, press 20 may measure the dynamic gap during
simulation to an accuracy of generally about 1 .mu.m.
[0066] Insulator plate 96 may be mounted to support block 94 and
heating/cooling block 98, such that insulator plate 96 may be
mounted between support block 94 and heating/cooling block 98.
Insulator plate 96 may insulate load cells 104 and accelerometers
102 from the varying temperatures of heating/cooling block 98.
[0067] Similar to heating/cooling block 88, the temperature of
heating/cooling block 98 may be controlled, including independently
controlled. In an embodiment, glycol lines may be connected to
heating/cooling block 98 to decrease the temperature of
heating/cooling block 98. Alternatively, liquids or refrigerants
other than glycol may be used. Similarly, it is recognized that any
means of cooling heating/cooling block 98 may be used to decrease
the temperature of heating/cooling block 98, such as air cooling by
circulating air through heating/cooling block 98, etc. In an
embodiment, heating cartridges may be placed in heating/cooling
block 98 to increase the temperature of heating/cooling block 98.
Alternatively, it is recognized that any technique for heating
heating/cooling block 98 may be used to increase the temperature of
heating/cooling block 98. Heating/cooling block 98 may further
include temperature sensors or thermocouples that measure the
temperature of heating/cooling block 98. Therefore, the temperature
of heating/cooling block 98 can be increased or decreased
automatically using drive controller 200 or an independent control
system to maintain a desired temperature throughout simulation.
[0068] Tooling plate 100 may be mounted to heating/cooling block
98. Alternatively, tooling plate 100 may be integral with
heating/cooling block 98. Tooling plate 100 may provide the
simulated surface of one of the compression rolls 12 or 14, shown
in FIG. 1. Typically, the compression roll simulated by tooling
plate 100 will be the opposite roll than is simulated by tooling
plate 86 of moving plate assembly 30. Tooling plate 100 may be
interchangeable and may be changed, as desired, to simulate
different deformation processes, such as activation, fusion
bonding, embossing, crimping, etc. FIGS. 12A and 12B illustrate
tooling plate 100 as having a substantially planar surface. Tooling
plate 100 may, however, include a protuberance, a pattern, a
plurality of protuberances or patterns, or any other characteristic
that is desired for the simulation.
[0069] In an embodiment, tooling plate 100 may be substantially
planar. Tooling plate 100 may simulate a smooth, flat, or blank
compression roll, i.e., an anvil roll, such as roll 14 shown in the
nip process of FIG. 1. Either, or both, tooling plate 86 or 100 may
provide a surface having a protuberance, a pattern, a plurality of
protuberances or patterns, etc., or may provide a smooth, flat
surface. That is, either tooling plate 86 or 100 may provide a
surface for simulating any type of process, such as activation,
fusion bonding, embossing, crimping, etc. Similarly, either tooling
plate 86 or 100 may provide a surface simulating an anvil roll.
Tooling plates 86 and 100 may, in an embodiment, provide the same
or substantially similar surfaces. Alternatively, tooling plates 86
and 100 may provide generally dissimilar surfaces.
[0070] Again, it is recognized that not all components described in
detail need be provided with all embodiments of press 20. For
example, position sensors 92, load cells 104, accelerometers 102,
insulator plate 96, heating/cooling block 98, glycol lines, heating
cartridges, tooling plate 100, etc. may be excluded or altered, and
the resulting press will remain in accordance with an embodiment of
press 20 of the present invention.
[0071] Material holder 106 may be removably located between moving
plate assembly 30 and backplate assembly 32, as shown in FIG. 10.
With reference to FIG. 13, material holder 106 may generally
include material clips 108 which may hold the ends of material
sample 110. Material holder 108 may be positioned such that
material clips 108 hold material sample 110 between tooling plate
86 of moving plate assembly 30 and tooling plate 100 of backplate
assembly 32. In a production line process, different workpiece/web
materials can exhibit different stress or strain characteristics as
they are moved through rolls, such as rolls 12 and 14. Similarly,
different processes, such as activation, fusion bonding, embossing,
crimping, and the like, may submit workpiece/web materials to
different stresses and strains. In other words, the workpiece/web
materials traveling through rolls 12 and 14 in a nip type process,
for example, can exhibit different extents of stretching as they
are passed between rolls 12 and 14. The amount of in-plane loading
on the workpiece can influence both the stress/strain of the
material during the deformation process and the resulting final
state of the material after the process is completed. As such, the
material holder 106 may be designed to apply in-plane stress/strain
to the material sample 110. In one embodiment, to create the
ability to simulate these differing stresses and strains of the
workpiece/web materials, material clips 108 may be movable, such
that any strain or stress can be applied to material sample
110.
[0072] As can be seen in FIGS. 6, 10, and 14, backblock 114 may be
attached to the back of backplate assembly 32. Backblock 114 may
further be attached to upper girdle 116. In an embodiment, linear
bearings 122 may be used to attach backblock 114 to upper girdle
116.
[0073] Linear bearings 122, in a further embodiment, may be
provided to permit backplate assembly 32 and backblock 114 to move
in a linear direction, should something happen that is undesirable
or unexpected. Upper girdle 116 may further be mounted to the inlet
areas 52 of base 22 to provide further support, strength, and
rigidity for backplate assembly 32. As such, backblock 114 may be
positioned in the area between inlet areas 52. In a further
embodiment, a second girdle plate may be located on the underneath
side of base 22 and attached to inlet areas 52 and backblock 114
and may provide further support. One or more of backblock 114,
upper girdle 116, and linear bearings 122 may be omitted from some
embodiments of press 20.
[0074] Backblock 114 may be further attached to safety release
plate 118. Safety release plate 118 may be mounted to backplate air
bag 34, as illustrated in FIG. 15. Safety release plate 118 and
backplate air bag 34 may be positioned in backplate air bag area 56
of base 22. Backplate air bag 34 may provide preload to keep safety
release plate 118 firmly and rigidly held in position against inlet
areas 52 unless potentially damaging forces are applied to the
backplate assembly 32, in which case the backplate air bag 34 may
allow the backplate assembly 32 to deflect, possibly preventing
damage to press 20 components. Alternatively, in some embodiments,
press 20 need not include safety release plate 118 nor backplate
air bag 34.
[0075] Drive controller 200 may be provided for controlling the
operation of actuator 26. In some embodiments, a suitable drive
controller may be a personal computer with suitable hardware and
programming. It is recognized that any suitable controller may be
used for controlling the operation of actuator 26. In an
embodiment, more than one controller may be suitable or desirable
to control the operation of actuator 26. Similarly, one or more
controllers may be provided to control the operation of other
components of press 20, including but not limited to
heating/cooling blocks 88 and 98, sensors 92, etc. Alternatively,
drive controller 200 may control the operation of all components of
press 20.
[0076] In an embodiment, there may be multiple segments of a motion
trajectory profile for press 20 of the present invention (see FIG.
18). A Rotary motion profile segment 150 may represent the
engagement state of moving plate assembly 30 with the workpiece W.
An Approach profile segment 152 may represent the transition from
the at-rest, retracted state of moving plate assembly 30 to the
engagement state. A Stationary profile segment 154 may represent
the at-rest, retracted state of moving plate assembly 30. In an
embodiment, rotary motion profile 150 need only be maintained while
tooling plate 100 is in contact with, or engages, the workpiece W.
Equations and calculations that may be used for determining rotary
motion profile 150 are described below.
[0077] The engagement of a protuberance 16 and a corresponding
section 14a of the engaging or second roll 14, as it may be
simulated by an embodiment of the press of the present invention,
may be defined differently depending on the type of process, e.g.,
fusion bonding, crimping, cutting, activation/ring rolling, channel
embossing, etc, that is being simulated. For example, during
simulation of an embossing or bonding type operation, engagement
may be defined in the following manner. The nominal thickness of a
workpiece W may be determined or provided. As illustrated in FIGS.
16A and 16B, a plane of zero engagement 130 can be determined by
moving tooling plate 86 forward in a very slow manner, so that no
acceleration or vibrations in backplate assembly 32 are excited,
until tooling plate 86, or a protuberance located on tooling plate
86, just touches tooling plate 100. Touching of tooling plate 86,
or a protuberance thereon, and tooling plate 100 may be determined
by a deviation of zero in the force measurement from load cells 104
in backplate assembly 32. Once touching occurs, the plane of zero
engagement 130 can be readily determined using the nominal
thickness of workpiece W, by moving a distance equal to the nominal
thickness of workpiece W from the plane of tooling plate 100.
Engagement may then be defined as:
E(t)=d.sub.0-d(t)
where E(t) 136 is the position of the protuberance during the
engagement of tooling plate 86 and workpiece W at time t; d.sub.0
132 is the distance for zero engagement; and d(t) 134 is the
distance of engagement at time t.
[0078] The actual engagement, in some embodiments, may include the
change in dimension of the protuberance parallel to the direction
of motion. Since the dimensional change might not be measured
during the process, the control algorithm may not take the change
into account. However; the dimensional change may be included
during the post-processing of the engagement data from the force
engagement curve. For a given force at time t and engagement E(t),
the dimensional change (assuming, for purposes of an exemplary
illustration, the protuberance is considered a simple vertical
column and the loading does not exceed the elastic limit of the
material that makes up the protuberance) may be estimated to
be:
.DELTA. armature - plate ( t ) = F ( t ) H 0 A 0 E ##EQU00001##
where .DELTA..sub.armature-plate(t) is the dimensional change of
the protuberance in the direction of engagement; F(t) is the
material force; H.sub.0 is the height or initial dimension of the
protuberance in the direction of engagement; A.sub.0 is the
cross-sectional area of the protuberance; and E is the elastic
modulus of the protuberance. If the shape of the protuberance is
complex and the loading is expected to exceed the elastic limit of
the material that makes up the protuberance, the change in the
dimension can be determined using numerical/computational means,
such as finite element analysis ("FEA"). Similarly, the actual
engagement may include the change in dimension of tooling plate 100
parallel to the direction of motion, i.e.,
.DELTA..sub.back-plate(t). In one embodiment, the change in
dimension may be determined using numerical/computational means,
such as FEA. Once the change in protuberance height and the
dimension change in tooling plate 100 are known, the stored
engagement data can be post-processed using the following
equation:
E(t).sub.actual=E(t).sub.measured-.DELTA..sub.armature-plate(t)-.DELTA..-
sub.back-plate(t)
[0079] In another example, during simulation of an activation type
operation, engagement may be defined in the following manner. The
geometry of the plates and/or protuberances that may be provided on
the plates may be known. As illustrated in FIGS. 17A and 17B, the
plane of zero engagement 140 may be determined by offsetting the
plane of tooling plate 100 by the height of the protuberances
extending from tooling plate 100. As above, engagement may then be
defined as:
E(t)=d.sub.0-d(t)
where E(t) 146 is the position of the protuberances during the
engagement of tooling plate 86 and a workpiece at time t; d.sub.0
142 is the distance for zero engagement; and d(t) 144 is the
distance of engagement at time t.
[0080] In an embodiment, during rotary motion profile 150, a point
site W.sub.PS on a workpiece W, such as a web of material, moves at
a velocity V.sub.W through a nip N defined by rolls 12 and 14 and
may be engaged by a protuberance 16 and a corresponding section 14a
of second roll 14 for a time period of 2T as it moves through the
nip N. One-half of 2T, or T, is the time for protuberance 16 to
reach the maximum depth of engagement. One-half of the total
engagement time 2T that the given point site W.sub.PS on the
workpiece W may be engaged by the protuberance 16 and the
corresponding section 14a of second roll 14 can be determined by
the following equation:
T - a cos [ 1 - E M D i ] [ D i 2 V w ] ##EQU00002##
where E.sub.M is the amount by which the point site W.sub.PS is
compressed from an initial thickness M.sub.T to a compressed final
thickness G by the protuberance 16 and the corresponding section
14a of second roll 14; D.sub.i is the diameter of the first and
second rolls 12 and 14 (assuming, for an exemplary embodiment, that
rolls 12 and 14 have the same diameter and that the lengths of the
protuberances 16 are included in the diameter of roll 12); and
V.sub.W is the workpiece velocity.
[0081] Using the equation for engagement time T, set out above, and
the predefined values for the process to be simulated, drive
controller 200 may determine the engagement time T, which is equal
to one-half of the total time period 2T that a given point site
W.sub.PS on a workpiece may be engaged by protuberance 16. The
engagement position of a protuberance 16 may be determined by drive
controller 200 using the following equation:
E ( t ) - E M - D i [ 1 - cos [ a cos ( 1 - E M D i ) ( t T - 1 ) ]
] ##EQU00003##
where E(t) is the position of the protuberance during engagement;
E.sub.M is the amount by which the point site W.sub.PS is
compressed by the protuberance 16 and the corresponding section 14a
of second roll 14 or the amount by which the point site W.sub.PS is
compressed by a protuberance on tooling plate 86 and the surface of
tooling plate 100; D.sub.i is the diameter of the first and second
rolls 12 and 14 (assuming, for an exemplary embodiment, that that
rolls 12 and 14 have the same diameter and that the lengths of the
protuberances 16 are included in the diameter of roll 12); t is
equal to 0 to 2T.
[0082] The velocity of the protuberance 16 at a given engagement
position may be determined by taking the first derivative of the
position value and may be represented by the following
equation:
t E ( t ) = - D i - sin [ a cos ( 1 - E M D i ) ( t T - 1 ) ] [ a
cos ( 1 - E M D i ) T ] ##EQU00004##
[0083] Similarly, the acceleration of the protuberance 16 at a
given engagement position of a protuberance may be determined by
taking the second derivative of the position value and may be
represented by the following equation:
2 t 2 E ( t ) = - D i - cos [ a cos ( 1 - E M D i ) ( t T - 1 ) ] [
a cos ( 1 - E M D i ) T ] 2 ##EQU00005##
[0084] To complete the motion trajectory calculation, an approach
curve may be calculated that transitions from the at-rest,
retracted state 154 of the moving plate assembly 30 to the
position, velocity, and acceleration state at the beginning of
rotary motion profile 150, set forth above.
[0085] In an embodiment, it may be desirable for the overall
trajectory to be smooth, as illustrated in FIG. 18. However, the
displacement profile does not need to be rotary in nature. That is,
the controller may be programmed to be linear, stepped, or
approximately saw tooth, as illustrated previously in FIGS. 4A, 4B,
and 4C, respectively. Discontinuities in the reference profile may
cause spikes in control command, overloading/saturating of control
system components, and/or reduce control accuracy. With this in
mind, there are six boundary conditions that could be satisfied.
The position, velocity, and acceleration at the beginning of
approach profile segment 152 could match the position, velocity,
and acceleration at the end of stationary profile segment 154, and
the position, velocity, and acceleration at the end of approach
profile segment 152 could match the position, velocity, and
acceleration at the beginning of rotary motion profile segment 150.
These boundary conditions may be satisfied by modeling approach
profile segment 152 with a fifth order polynomial, in the form
of:
x(t)=p.sub.0+p.sub.1t+p.sub.2t.sup.2+p.sub.3t.sup.3+p.sub.4t.sup.4+p.sub-
.5t.sup.5
The first three boundary conditions, i.e., the position, velocity,
and acceleration at the beginning of approach profile segment 152
(and the end of stationary profile segment 154), may, in an
embodiment, be:
x(0)=0
v(0)=0
a(0)=0
since the moving plate assembly 30 is in an at-rest, retracted
state. In some embodiments, these conditions can be satisfied by
choosing the parameters:
p.sub.0=0
p.sub.1=0
p.sub.2=0
In some embodiments, matching additional derivatives beyond
velocity and acceleration may be desirable and beneficial.
[0086] The remaining three boundary conditions, i.e., the position,
velocity, and acceleration at the end of approach profile segment
152 (and the beginning of rotary motion profile segment 154) may
comprise the equations:
x(t.sub.f)=x.sub.i=p.sub.3t.sub.f.sup.3+p.sub.4t.sub.f.sup.4+p.sub.5t.su-
p.5
v(t.sub.f)=v.sub.i=3p.sub.3t.sup.2+4p.sub.4t.sup.3+5p.sub.5t.sub.f.sup.4
a(t.sub.f)=a.sub.i=6p.sub.3t.sub.f+12p.sub.4t.sub.f.sup.2+20p.sub.5t.sub-
.f.sup.3
where x.sub.i is the position at the initiation of the rotary
motion profile 150; v.sub.i is the velocity at the initiation of
the rotary motion profile 150; and a.sub.i is the acceleration at
the initiation of the rotary motion profile 150. These equations
may be expressed in matrix form:
{ x i v i a i } = [ t f 3 t f 4 t f 5 3 t f 2 4 t f 3 5 t f 4 6 p 3
t f 12 t f 2 20 t f 3 ] { p 3 p 4 p 5 } ##EQU00006##
Solving the matrix for the polynomial coefficients, the following
matrix equation is achieved:
{ p 3 p 4 p 5 } - [ t f 3 t f 4 t f 5 3 t f 2 4 t f 3 5 t f 4 6 p 3
t f 12 t f 2 20 t f 3 ] - 1 { x i v i a i } ##EQU00007##
[0087] The final parameter to select is t.sub.f, which is the time
for the moving plate assembly 30 to travel from the at-rest,
retracted position 154 to the beginning of rotary motion profile
segment 150. In an embodiment, the parameter t.sub.f, may be
selected to minimize the maximum velocity that moving plate
assembly 30 achieves throughout approach profile 152. This may be
done by evaluating the calculated approach profile 152 for a range
of values for t.sub.f in time increments of the drive controller
200 integer sample rate or controller time step value and
determining the maximum velocity for each value.
[0088] FIG. 19 illustrates the variation in the maximum velocity
achieved in approach profile 152 as a function of the approach time
for an exemplary profile. The resulting approach profile
displacement, velocity, and acceleration curves are illustrated in
FIG. 20. The trajectory profile may be symmetric about the point of
maximum extension of the moving plate assembly (i.e., the minimum
gap between tooling plates 86 and 100). Therefore, retraction
profile 156, shown in FIG. 18, may be identical to that of approach
profile 152, although reversed with respect to time. However, it is
recognized that retraction profile 156 need not be symmetrically
identical to that of approach profile 152. The resulting
displacement, velocity, and acceleration curves of the complete
trajectory profile are shown in FIG. 21.
[0089] In an embodiment, a production line process, such as a nip
type process, may be simulated by press 20 of the present invention
in the following manner:
[0090] Prior to running a simulation, an engineer/technician may
determine or may define one or more of the following parameters
concerning the process to be simulated: a desired workpiece
velocity V.sub.W, i.e., the velocity at which the workpiece W would
run if passed between a pair of first and second rolls 12 and 14;
the diameter D.sub.i of the first and second rolls 12 and 14; and
an amount E.sub.M by which a point site W.sub.PS is compressed by a
first roll protuberance 16 and the corresponding section 14a of
second roll 14, i.e., the workpiece initial thickness M.sub.T less
the workpiece final thickness G.
[0091] Drive controller 200 may then determine the engagement time
T using the equation for engagement time T, set out above, and the
predefined values for the process to be simulated. Subsequently,
using the result for engagement time T from the previous
calculation, drive controller 200 may determine the engagement
position, velocity, and acceleration for any given time t during
the rotary motion profile segment, where the time t will, in an
embodiment, typically range from 0 to 2T, as previously
described.
[0092] Drive controller 200 may then determine an approach curve
that transitions from the at-rest, retracted state 154 of the
moving plate assembly 30 to the position, velocity, and
acceleration state at the beginning of rotary motion profile 150.
Similarly, drive controller 200 may determine a retraction profile
156. Again, the retraction profile 156, may be identical to that of
approach profile 152, although reversed with respect to time. It is
recognized that retraction profile 156 need not be symmetrically
identical to that of approach profile 152.
[0093] Drive controller 200 may determine the initial press
position control loop commands and iterative update of the commands
to reduce profile error. In other embodiments, as previously
mentioned, an independent controller may be used instead of
controller 200. However, for purposes of illustration, controller
200 will be referenced in relation to the control loop. In an
embodiment, a proportional, integral, differential ("PID") position
feedback loop may be used for real-time control of the armature,
e.g., forward moving face 112, position. The linear encoder signal,
as previously described, may be used as the position reference
feedback. The encoder may be low noise, high resolution.
Furthermore, the encoder may have a measurement range that covers
the entire range of motion of the armature. Controller 200 may be a
very high speed and high gain system. In an embodiment, extremely
accurate profile motion may be obtained by precise, iterative
calculation of the closed loop, reference position commands
utilized by controller 200.
[0094] In a system with a position loop having a perfect response,
i.e., unity gain and zero phase, over the frequency bandwidth of
the desired armature trajectory, the desired trajectory, as
described above, may be the appropriate command for the position
loop. However, where this is not the case, the loop command may be
modified to achieve higher initial trajectory accuracy.
[0095] A frequency domain model may be utilized to calculate the
position loop command. The press 20 may have an
automatic-identification capability, which measures a frequency
domain model of the press position loop characteristics comprising
of a frequency response function ("FRF") between encoder response
and position loop command.
[0096] A process to generate a valid FRF may be used to excite the
system with an excitation signal that has energy across the entire
frequency band of interest, and measure the excitation and response
signals. The two signals may be transformed to the frequency domain
using the fast Fourier transform ("FFT"). The complex ratio of
phase and magnitude may be calculated between the two signals.
[0097] To reduce noise and improve the accuracy of the estimated
FRF, an averaged, "H1" FRF may be calculated. The procedure for
obtaining an averaged, "H1" FRF is now described. Multiple (N) time
histories of excitation commands, c.sub.i(t), i=1, . . . N, and
associated encoder responses, e.sub.i(t), i=1, . . . N, may be
measured. These may be transformed via Fourier Transform to the
frequency domain:
C.sub.i(w)=I(c.sub.i(t)
E.sub.i(w)=I(e.sub.i(t))
wherein w denotes the frequency, which ranges from 0 to 1/2 of the
frequency at which the time data was sampled, and I denotes the
FFT. The averaged cross spectrum between the encoder response and
input command may be calculated using the equation:
G ec ( w ) = 1 N i = 1 N E i ( w ) C i * ( w ) ##EQU00008##
wherein the "*" superscript indicates complex conjugate. The
averaged power spectrum of the input command may be calculated
using the equation:
G ec ( w ) = 1 N i = 1 N C i ( w ) C i * ( w ) ##EQU00009##
The FRF may be calculated as the ratio of the averaged cross
spectrum and the averaged power spectrum:
H ec ( w ) = G ec ( w ) G ec ( w ) ##EQU00010##
[0098] The system response FRF, H.sub.ec, calculated above,
satisfies the relationship:
E(w)=H.sub.ec(w)C(w)
The frequency domain representation of the command that may achieve
a desired encoder profile can be calculated as:
C ( w ) = H ec - 1 ( w ) E ( w ) = E ( w ) H ec ( w )
##EQU00011##
[0099] If the desired time domain encoder profile is p(t), the
command that will achieve that encoder profile may be calculated,
within the limits of accuracy of the system response FRF and system
noise, variation, and nonlinearity, as described below.
[0100] First, the desired time domain profile may be transformed to
the frequency domain:
P(w)=I(p(t)
The frequency domain representation of the profile (or profile
spectrum) may then be divided, on a frequency by frequency basis,
by the system response FRF to calculate the desired frequency
domain command:
C ( w ) = P ( w ) H ec ( w ) ##EQU00012##
The frequency domain command may then be inversely transformed to
the time domain:
c(t)=I.sup.-1(C(w))
[0101] When the press 20 has run a cycle, it may have the
capability to examine the resulting profile error and update the
command to reduce the error on the next cycle. In an embodiment,
three operations may be performed, including command update to
reduce error, merge encoder and optical sensor data to obtain
desired gap error, and select and perform either fast or safe
iteration updates.
[0102] The command update procedure, may be similar to the initial
command calculation procedure described above. However, the command
update procedure may operate on the profile error. Quantities of
interest relating to the command update procedure may comprise the
desired profile, p(t), the actual, measured profile, p.sub.m(t),
the command, c(t), and the updated command, c.sub.u(t).
[0103] The profile error, p.sub.e(t), may be calculated as the
difference of the desired profile and the measured profile:
p.sub.e(t)=p(t)-p.sub.m(t)
The profile error may be windowed with a window that has unity
weighting over the rotary motion section of the profile and which
smoothly transitions to zero at the ends of the profile. This can
concentrate the control effort in the section of the profile that
may be most important. An incremental change in the command,
.DELTA.c(t), may be calculated using the command calculation
procedure described previously, but substituting the profile error
for the desired profile. The updated command may then be calculated
as the original command plus the change in command:
c.sub.u(t)=c(t)+.DELTA.c(t)
[0104] Due to deflections that may occur in press 20 mechanical
components at extremely high acceleration rates at which the press
20 may operate, the encoder and optical sensor readings may not
agree exactly. Since the real-time position control loop may use
the encoder as the reference feedback transducer, adjustments may
be made in the encoder profile command in order to achieve the
desired gap profile as measured by the optical gap sensors. This
may be achieved by utilizing the optical sensor measurements to
calculate the profile error.
[0105] Optical sensors 92 may have a maximum accurate measurement
range. In an embodiment, optical sensors 92 may have a maximum
accurate measurement range of about 15 mm. The total travel of the
armature of the actuator 26 may extend beyond 15 mm. Therefore, in
an embodiment, the optical sensor measurements and the encoder
measurement may need to be stitched together, or combined.
[0106] In an embodiment, stitching of the measurements may be
accomplished as follows. The optical sensor data may be truncated
to the time interval from about 0.8 msec prior to, and 0.8 msec
after, the cycle rotary profile begins and ends. The values of the
encoder data and optical sensor data at the endpoints of the
truncated time interval may be determined, and the offset between
the data may be calculated. The optical sensor data may be low-pass
filtered to determine endpoint values to minimize noise spikes at
the endpoints that may introduce error in the offset determination.
A linear slope may be added to the encoder data, so that it matches
the amplitude of the optical sensor data at the time interval
endpoints. In other embodiments, it is recognized that other
suitable methods of combining the measurements, including other
time intervals, may be utilized in accordance with the present
invention.
[0107] In an embodiment, the press 20 may be run in a no-iteration
mode or an iteration mode. In a no-iteration mode, no update of the
command is performed. The iteration mode may further be broken into
more than one iteration mode. For example, in one embodiment, the
iteration mode may be further broken into a safe-mode-iteration and
fast-iteration. In safe-mode-iteration, the command may be updated
by a lower percentage than 100% of the calculated command update.
For example, the command may be updated by 10%, 25%, 50%, 65%, 75%,
85%, or other suitable percentage of the calculated command update.
Normally, -mode-iteration may be used when the actual profile is
within the accuracy range required for the testing being conducted.
In a further embodiment, in safe-mode-iteration, gradual updates to
the command may be made which average the update over many cycles,
thus, reducing the effect of random variables, such as material
properties, electrical noise, etc.
[0108] Normally, safe-mode-iteration may be used to ensure the
armature profile does not overshoot and cause tooling plates 86 and
100 (or protuberances thereorn to impact and possibly cause damage.
If the profile gap is not within the accuracy range required for
the testing being conducted, such as greater than 2 mm, for one
example, fast-iteration may be used and the command may be updated
with approximately 100% of the calculated command update, or other
suitable percentage generally near 100%.
[0109] Prior to simulation, a workpiece/web material, or sample
thereof, may be placed in material holder 106. As previously
stated, to create the ability to simulate differing stresses and
strains of the workpiece/web materials, material clips 108 of
material holder 106 may be movable, such that any strain or stress
can be applied to the workpiece/web material.
[0110] In an embodiment, simulation of a production line process
and the effects of the process on the workpiece/web material may
include simulating actual roll speeds, forces, cuts, perforations,
bonds, etc. However, simulation of a production line process, in
some embodiments, comprises simulating a wide range of roll speeds,
forces, cuts, perforations, bonds, etc., including roll speeds,
forces, cuts, perforations, bonds, etc. substantially near actual
roll speeds, forces, cuts, perforations, bonds, etc. In some
embodiments, any roll speeds, forces, cuts, perforations, bonds,
etc. may be simulated using press 20 of the present invention.
Additionally, in some embodiments, it may be desirable to perform a
variety of material testing applications/modes including, but not
limited to, simple compression, planar, simple shear, oscillatory
viscoelasticity, etc. In further embodiments yet, the invention
described herein may be used to simulate the shaking that a
workpiece may experience during a production line process, such as
folding.
[0111] In some embodiments, the invention described herein may be
used to simulate combined multiaxial loading, such as differential
roll surface speed, combined loading including compression and
transverse shearing, and combined loading including compression and
in-plane shearing. However, it is recognized that other combined
multiaxial loading simulations may be performed using the various
embodiments of the press described herein. In certain embodiments,
the present invention may be used to measure and understand a
material's mechanical response during various processes, as well as
measuring a material's constitutive properties.
[0112] The dimensions and values disclosed herein are not to be
understood as being strictly limited to the exact numerical values
recited. Instead, unless otherwise specified, each such dimension
is intended to mean both the recited value and a functionally
equivalent range surrounding that value. For example, a dimension
disclosed as "40 mm" is intended to mean "about 40 mm."
[0113] All documents cited in the Detailed Description of the
Invention are, in relevant part, incorporated herein by reference;
the citation of any document is not to be construed as an admission
that it is prior art with respect to the present invention. To the
extent that any meaning or definition of a term in this document
conflicts with any meaning or definition of the same term in a
document incorporated by reference, the meaning or definition
assigned to that term in this document shall govern.
[0114] While particular embodiments of the invention have been
illustrated and described, it would be obvious to those skilled in
the art that various other changes and modifications can be made
without departing from the scope of the invention. It is therefore
intended to cover in the appended claims all such changes and
modifications that are within the scope of this invention.
* * * * *