Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
~SSEMBLY SYSTEM FOR SEAMED ARTICLES
REFERENCE TO RELATED APPLICATIONS
. . _ . _ . . _ . _ .
The subject matter of this application is
related to that of UOS. Patent No. 4,401,044, entitled
5"5ystem and Method for Manufacturing Seamed Articles",
and U.S. Patent No. 4,457,243
entitled "Automated Seamed Joining Apparatus", filed
February 4, l9B3, and ~.S. Pa~ent No. 4,512,269,
enti-tled "Automated Assembly System For Seamed
10 Articles", filed July 19, 1983.
BACKGROUND OF THE INVENTION
This invention relates to the assembly of
seamed articles made from limp material, such as
fabric. In particular, ~he invention relates to
15systems for au~omated, or computer-controlled, ~æsembly
of seamed articles from limp material.
Conventional assembly line manufacture of
seamed article6 construc~ed of limp ~abric consists of
a series of manually con~rolled assembly operation~.
205enerally tactile presentation and control of the
fabric-to-be-joined is made to the joining, or ~ewing,
head under manual controll One drawbacX of ~his appli-
cation techni~ue is that the technique i5 labor
intensive; ~hat is, a large portion o ~he cost for
25manufacture is ~pent on labor. To reduce coRt, auto-
mated or computer-controlled manufacturing techniques
have been proposed in the prior art.
An automated approach to fabric presentation
and control is disclo~ed in U.S. Patent NoO 4,457,243.
30-As ~here disclosed, pairs of belts
--2--
assemblies are positioned on either side of a planar
fabric locus. The respective bel~ assemblies are dri-
ven to selectively provide relative motion along a
reference axis to layers of fabric lying in the fabric
51Ocus. A joining, or sewing, head i~ adapted for
motion adjacent to the abric locus along an axis per-
pendicular to the reference axis. The respective belts
main~ain control of the limp fabric in ~he region tra~
versed by the sewing head, with the respective belts
lObeing selectively retrac~ed, permitting passage there-
between of the sewing head as it advances along its
axis of motion. With this approach, control of the
limp fabric is permitted in the regions which are to be
joined.
Systems ~or the manufact~re of seamed
articles from a strip of limp abric disclosed in
U.S. Patent No. 4,512,269 provide more
precise "near ield" control of limp fabric, that i~
fabric control in regions close to the sewing head.
20Those systems include a feeder for selectively feeding
these strips of limp fabric in the direction of a first
(Y) reference axis. Control of pre~entation may also
be maintained in a second (X) axis perpendicular t~ and
intersecting the Y axls.
In some formsi a folding apparatus controls
the position of the fabric ~o that the strip of fabric
is folded onto itself along a fold axis offset from the
axis of feed (Y axis) so that there is a folded portion
having an upper layer overlying a lower layer. A sup-
30port is used ~o position the upper and lower layers ofthe folded portion in a substantially planar fabric
locus.
In one form of tho~P ~ys~ems, the 6upport
includes a frame member, a support assembly coupled to
,~
~5~
--3--
the feeder, and a drive motor and an associated linkage
for selectively positioning the frame member with
respect to the support assembly in the direction of the
X axis. A pair of lower belt assemblies is coupled to
5the frame member, where each lower belt assembly inclu-
des a plurality of continuous loop lower belts
underlying the fabric locus. The lower belts are
adapted on their outer, uppermost surface for fric-
tional coupling with the lower layer of the folded por-
lOtion. ~le lower belt assemblies are adjacentlypositioned along the X axis, with each assembly
including an associated driver for ~electively driving
the lower belts so that the lower fabric layer coupled
to those belts is positionable in the direction of the
15X axis.
A pair of upper belt assemblies is coupled to
the frame member as well. The upper belt assemblies
are adapted to be positioned to overlie the lower belt
assemblies. Each of the upper belt assemblies includes
20a plurality of upper belts (which may be positioned
opposite the respective lower belts). The upper belts
have planar lowermost portions spaced apart rom the
uppermost of the lower belts. The upper belts are
adapted on their outer, lowermost surface for fric-
25tional coupling with the upper layer of the folded por-
tion. Each of the upper belt assembiies has an
associated driver for selectively driving those u~per
belts so that the lower layer coupled to those belts is
positionable in the direction of the X axis. The
30region between the lowermost portions of the upper
belts and the uppermost portions of the lower belts
defines ~he fabric locus, so that the fabric locus is
substantially parallel to the plane formed by the
intersecting X and Y axes.
In general, a computer-controller is used to
selectively control the drivers or the respective
_4_ ~5~
belts so that the upper and lower layers may be
substantially independently positioned in the direction
of the X axis along the fabric locus~ In alternative
forms of those systems, the respective bel~ assemblies
5may be con~rollable in the Y axis direction as well, ~o
that the upper and lower layers may be substantially
independently positioned in the direction of both the X
and Y axes along the fabric locus, th~reby permitting
control motion of the respective layers in those direc-
lOtions.
A fabric joiner, or sewing head, includes anupper assembly and a lower assembly. These upper and
lower assemblies are adapted for tandem motion along
the direction parallel to the Y axis between ~he upper
15belt assemblies and the lower belt assemblies. An
associated driver provides control of the position of
the upper and lower assemblies of the joiner along its
axis of motion. The joiner is selectively operable to
form seams in fabric in the ~abri~ locu~ under the
20con~rol of a computer-controller.
In one form of the systems of those systems,
at least one pair of ~he pairs of the adjacent belt
assemblies includes opposing pairR of closed loop belts
and an associated con~roller adapted so that the pairs
250f the closed loop belts are selectively retractable in
the X direction ~o permit passage of the joining head
therebetween in the Y direction, for examplet in the
manner disclosed in V.S. Patent No. 4,457,243.
The joining head may include a needle
assembly having a thread-carrying, elonga~ed needle
extending along a needle reference axis perpendicular
to the fabric locus. In operation, the needle i5
driven through ~he fabric locu~ in a reciprocal motion
`~,
A
--5--
along the needle reference axis. The needle assembly
further includes an upper feed dog assembly which is
responsive to an applied upper dog drive signal for
selectively driving the uppermost layer of fabric in
5the region adjacent to the needle in the direction of
an upper axis which is perpendicular to the needle
reference axis.
A bobbin assembly is generally used in those
systems and is adapted for interaction with the needle
loassembly to form the stitches of the seam. The bobbin
assembly includes a lower feed dog assembly which is
responsive to a lower dog drive signal for selectively
driving the lowermost layer of fabric in the region
adjacent to the needle in the direction of a lower axis
15which is perpendicular to the needle reference axis.
In one form of those systems, a controller
generates a part assembly signal representative of the
desired position of the junction of the layers of
fabric relative to those layers. Registration sensors
20provide signals representative of the current position
of the respective uppermost and lowermost fabric
layers. A controller provides overall control for the
belt assemblies as well as the feed dogs and needle and
bobbin assembly rotational and feed dog control, in
250rder to achieve coordinated motions of the respective
assemblies. With this configuration, the respective
belt assemblies provide far field, or global, position
control for the upper and lower fabric layers. The
feed dogs provide near field, or local, position
30control for the upper and lower layers of fabric in the
regions near the needle of the joining head.
While the above-referenced systems do effec
tively provide approaches for the automated assembly of
seamed articles, there are limitations in those opera-
1 ~ e
--6--tions, particularly regarding the positioning,
orienting an~ folding of limp fabric in preparation for
joining of seams. Further, automated assembly systems
require a feedback control system in order to
5accomplish these preparatory operations. In all such
operations, it is important that accurate and repeated
edge positioning of fabric be achieved in order to
assure uniform quality of garment assembly. Moreover,
these aspects are particularly important in view of
10desired high volume, and in view of the prior art
requirement of specialized assemhlies, requiring
pattern- and size- dependent clamps or fixtures.
Another factor for such automated assembly systems is
that such systems must be cost efective compared with
l~the existing approaches.
Accordingly, it is an object of the present
invention to provide an improved system for automatic
assembly ol seamed articles.
Another object is to provide an improved
20automated assembly system for seamed articles including
a relatively low cost optical feedbacX system
controlling fabric location and orientation.
Yet another object is to provide an improved
folding apparatus for folding fabric in automated
25seamed article assembly systems.
SUMMARY OF THE INVENTION
.
Briefly, the present invention is directed to
a limp material handling system including a manipu-
lating system for selectively manipulating one or more
301ayers of limp material. The manipulating system
includes a support assembly adapted to support the
material on a reference surface. The manipulating
~ 7--
system further includes a selectively operable fold
assembly which includes a gripping apparatus for mecha~
nically coupling to (or grapping or gripping) a cur-
vilinear region of at least an uppermost layer of
smaterial on the support surface, and an apparatus for
contour controlling and positioning for that gripped
region of material, and for releasing that gripped
region. In forms of the inventon adapted for folding
limp material, the fold assembly further includes
lOapparatus for selectively lifting and lowering a
gripped region of material, so that a lifted region may
be lowered down to the reference surface or the next
uppermost layer of material overlying that reference
surface. The gripping and releasing apparatus, the
15contour controlling and positioning apparatus and the
lifting and lowering apparatus are all selectively
operable under control of a control apparatus, which is
generally controlled by a microcomputer in the pre-
ferred ! orms o the invention.
Generally, the fold assembly is operative to
grip a curvilinear region of the material, then to
control the curvature of that gripped curvilinear
region so that the region has a selected contour, and
to selectively translate and rotate that gripped region
25to a selected location overlying an associated cur-
vilinear region of the reference surface, and then the
material is released. To fold the material, a lifting
operation for the gripped resion is interspersed with
these operations. Then, that translated and/or rotated
30and/or reconfigured curvilinear region is lowered to
the underlying associated curvilinear region of the
reference surface, or onto material overlying that
associated curvilinear region on the reference surface.
Particularly, in article assembly systems in
3saccordance with the invention, the system further
8~;
--8--
includes a seam joining apparatus, such as a sewing
machine, which is selectively positioned along a
reference axls. The seam joining apparatus is adapted
to selectively join adjacent regions of one or more
slayers of the limp material elements passing through
that reference axis. The assembly system further
includes a multiple parallel endless belt assembly,
which is adapted to selectively transport and align the
limp material in order to present that material to the
lOseam joining apparatus at points on the first reference
axis.
This belt assembly also provides selective
orientation of the limp material elements to be joined.
The respective belts of the belt assembly are selec~
15tively controllable to provide a desired tension in the
limp material elements in regions of the limp material
adjacent to and including the first reference axis, so
that seam joining occur under controlled tension~
Furthermore, the belts may be selectively driven in
200rder to reposition upper and lower layers of a multi-
layer material at the sewing head in order to
accomplish relative positioning of those layers, and
further to provide capability to achieve easing and the
generation of three dimensional seams.
All of these operations are provided under
the control of an assembly controller which establishes
the selected positioning, folding and joining of the
limp material to assemble seamed articles.
In some forms of the invention, an optical
30sensing system provides optical feedback to the
controller in order to ~ense the current position and
various characteristics of the material which is being
assembled into articles. The optical sensing system
provides information representative of the edges of
. .
~s~
~9--
such materials as well, so that the folding apparatus
may operate to accomplish the desired manipulations
and,~or folds by con~.rolling the positioning of the
edges of the material in such a manner to achieve the
5desired manipulation and/or folding.
In one form of the invention, a particularly
cost effective optical sensing system is provided by
incorporating a television camera for generating video
sisnals using a common axis illumination system. This
10configuration provides video signals representative of
an image along the camera's optical axis of the
reference surface and any limp material on that surface
within the field of view of the camera. The reference
surface provides a relatively high contrast optical
15reflectivity with respect to material positioned on
that surface.
With this configuration, the article assembly
system may construct seamed articles, such as garments,
in a manner providing accurate and repeatable edge
20positionin~, thereby leading to highly uniform quality
of garment assembly~ Particularly, the folding a~para-
tus is well adapted to attaching to the limp material,
picking that edge up, reshaping that edge as desired,
and moving it and placing it down elsewhere on the sur-
25face with substantially high accuracyO The reshapingof the edge permits matching to another edge of
material already on the surface, so that the overlying
edges may be then joined to form a desired seam,
thereby permitting joining of dissimilarly-shaped
30edges.
BRIFF DESCRIPTION OF THE DRAWINGS
The foregoing and other objects of this
invention, the various features ~hereof, as well as the
--10--
invention itself, may be more fully understood from the
following description, when read together with the
accompanying drawings in which:
Fig. 1 shows an isometric representation of
5the principal elements of an exemplary embodiment of
the present invention:
Fig. 2 shows a partially cutaway view of a
support table for the system of Fig. l;
Fig. 3 shows schematically the upper endless
belts of the system of Fig. l;
Figs. 4A and 4B illustrate the opera~ion of
the xetractable belts of the system of Fig. l;
Fig. 5 shows an iso~etric representation of
an exemplary fabric folding system for use with the
15system of Fig. 1
Figs. 6A-6F illustrate the folding and sewing
operations performed during the automated assembly of a
sleeve by the system of Fig. l;
Fig. 7 illustrates the television camera and
200n-axis light source for the system of Fig. l; and
Fig. 8 shows in block diagram form an
e~:e;..~.~lary configuration for generating the position
signals for use with the system in Fig. 1.
~;~5~
DESCRIPTIO~ OF THE PREFERRED EMBODIMENT
Fig. 1 shows an isometric representation o~
principal elements of a preferred form of an assembly
system 110 together with a set of intersecting
5reference coordinate axes X, Y and Z. The system 110
includes two support tables 112 and 114 and a seam
joining assembly 116. The system 110 further includes
an optical sensor system overlying table 112 and
including a television camera 117 and a common-axis
lOillumination system lI8. In alternative embodiments,
an additional optical sensor system may similarly
overlie table 114, for use in loading or unloading and
orienting limp material elements, for example.
~ach of the support tables 112 and 114 inclu-
15des a respective one of planar upper surfaces 112a and114a. In alternative e~bodiments, other or both of the
surfaces 112a and 114a may differ from planar. For
example, those surfaces may be cylindrical about an
axis parallel to thè Y axis.
A set of parallel endless belts ~120 an 122)
is affixed to each of tables 112 and 114. Each set of
belts 120 and 122 is pivotable about a respective one
of axes 120a and 122a each of which is parallel to the
Y axis from a position substantially parallel to one of
25surfaces 112a and 114a (closed) to a position substan-
tially perpendicular to one of those surfaces (open).
In Fig. 1, belt set 120 is shown in a partially open
position, and belt set 122 is shown in a closed posi-
tion substantially parallel to the top surface 114a of
30table 114.
Fig. 2 shows a partially cutaway view of the
support table 112. l~at support table 112 as shown
includes a perforated retro-reflective surface which
~
~ 12-
forms the surface 112a. In the present embodirnent, the
surface 112a iâ formed by retro-reflective material
~ype for example as manufactured by 3M Corporation,
where that retro-reflective material forming the sur-
5face 112a includes a rectangular array of holes, eachhole having a diameter equal to 1/32 inches, with the
array having a center-to-center spacing of 1/16 inches.
In alternate embodiments, the array may be other than
rectangular, for example, hexagonal or spiral or cir-
lOcular with holes having a sufficient diameter and theadjacent holes of the array having center-to-center
spacing appropriate to permit sufficient air mass flow
therethrough to provide a suitable vacuum for holding
limp material down to the surface. By the way of
15example, the array of holes in surface 112a may be
established using a commercial laser.
In the presently described embodiments, the
upper surface 112a overlies an aluminum plate having an
array of holes which substantially matches the array o
20holes in the surface 112a. That aluminum plate 130
overlies a composite beam honeycomb table top 132 which
includes an array of honeycomb tubular structures
extending in the direction of the Z axis. That
honeycomb table top 132 is supported over a multiple
25plenum valve module which provides selectively operable
rows of valves. In Fig. 2, there are eight rows of
valves shown, with 6iX of those rows in the open posi-
tion and two of those ro~s in the closed position~ The
valve module 134 is coupled to a vacuum blower 136
30which in turn is driven by a mo~or 138. With this con-
figuration, a vacuum is selectively provided to various
regions at surface 112a. The vacuum is particularly
useful in holding various layers of material in a
desired position on surface 112a. The positionin may
35 be accomplished by a material folding or by a material
manipulator, for example. The surface 112a also has
~s~
-13-
retro-reflective optical properties so that with top
lighting, reflective light is directed in the Z direc-
~ion to provide a high contrast background against any
cloth object placed on surface 112a. Th~ latter
5feature is particularly useful in systems ha~ing opti-
cal sensors which can identify the location and orien-
tation of material on surface 112a.
The sewing assembly 116 includes a sewing
machine 140 adapted for linear rnotion along the Y axis.
10The sewing machine is also pivotable about its needle
axis as driven by control 124 by ~ay of motor 142 and
gear assembly 144. The sewing assembly 116 further
includes an interlocking belt asse~nbly including a
first set of parallel endless belts 150 and a second
15set of parallel endless belts 152. The belts of sets
150 and 152 are adapted so that their lower surface may
frictionally drive material between those lower sur-
faces and an underlying support surface 160 which is
generally in continuous with ~urfaces 112a and 114a,
20un~er the control of the controller 1~4.
Fig. 3 shows the belt assemblies 120 150,
152, and 122, in schematic Eorm, together with the
sewing machine 140, wherein the belt sets 150 and 152
include alternating sets of three roller endless belts
25and two point continuous belts. In operation, the
controller 124 controls the belts adjacent to the
sewing head of sewing machine 140 to be retracted from
the locus of the needle while that needle is in the
region between the belts. Otherwise, the belts of the
30Opposed sets 150 and 152 are adjacent to each other.
The belts may be driven by controller 124 in a manner
providing controlled fabric tension for fabric between
the lower surface of the belts of sets lSO and 152 and
t-he upper surface 158. In various embodiments o~ the
35invention, the surface 158 may also include multiple
1~58~6
-14-
endless belt assemblies underlying respective belts of
sets 150 and 15~. The latter belt sets are also
controlled by the controller 1~4 in order to achieve
substantially independent control of upper and lo~er
slayers of fabric positioned between the sets of belts
150 and 152 and those sets underlying sets 150 and 152.
By way of example, the belts may be 0.03 to
Q.04 inches thick, 3/8 inch wide neoprene toothed
timing belts with polyester fiber reinforcement sup-
lOported by toothed roller assemblies. A layer ofpolyurethane foam is attached to the outer belt ~ur-
faces with adhesive. With this configurationt the foam
provide substantial frictional contact with material
adjacent to the bel~s so that as the belt moves, it
15positions the fabric adjacent thereto in the
corresponding manner. For the upper belts the layer is
3/8 inches thick and for the lower belts the layer is
1/4 inches thick. The thicker layer provides increased
adapability for materials characterized by varying
20thicknesses.
Fig. 4A shows two interlocking belts of the
sets 150 and 152, where the sewing machine head 140a is
positioned other than between these two belts. Fig. 4B
shows those same interlocking belts when the sewing
25head 140a is positioned between those two belts 150a
and 152a. With the present embodiment, as limp fabric
to be ~ewn is adjustably positioned between the belts
of sets of 150 and 152 and the surface 160, the sewing
machine 140 may be selectively controlled to traverse
30the gaps established by the retracting belts along axis
parallel to the Y axis of machine 140 so ~hat selective
stitching may be accomplished on that fabric, under the
control of controller 124.
The system 110 further includes a material
35manipulation system for fabric on the support table
-15-
112. That manipulation system includes the controller
124, and a folding assembly 160. The folding assembly
160 includes a controllable arm portion 162 which is
selectively movable in the Z direction and selectively
5rotatable about the axis 170. The folding assembly 160
includes a hinged, linearly segmented assembly 174.
That assembly includes three elongated segments 180,
182, and 184. Each of the segments 182 and 184 is
selectively rotatable with respect to segment 180 about
lOone of axes 190 and 192, so that the orientation of
those segments 182 and 184 are selectively controlled
with respect to the angular orientation of segment 180,
all under the control of controller 124. The segment
180 is rotatable about the axis 186 under the control
15Of controller 124. Each of segments 180, 182 and 184
includes a plurality ~f gripping elements distributed
along the principle axis of that segment.
The gripping elements are denoted in Fig. 1
by reference designation 180a, 182a and 184a. Each of
20the gripping elements is adapted for selectively
gripping regions of any fabric underlying those ele-
ments. The arm por~ion 162 is selectively controllable
in the Z direction. As a result, when the gripping
elements are afixed to a portion of the material, tha~
25portion may be selectively lifted and then lowered (in
the Z direction) with respect to the surface 112a. In
the present embodiment, the elements 180a, 182a and
184a are also each selectively movable in a direction
parallel to the X-Y plane in the direction perpen-
30dicular to the principle axes of the respective ones ofseg~ents 180, 182 and lB4. The gripping elements 180~,
182a and 184a are also selectively rotatable about an
axis 186.
With this configuration, the folding assembly
35160 may be used as a material manipulator for material
.~I./fz~S~
on surface 112a, whereby selective curvilinear portions
of that material may be sequentially grabbed by the
gripping elements, and then translated and/or rotated
and/or reshaped, and then released. The folding
sassembly 160 may also be used as a material folder by
selectively performing the operations described for the
manipulator, interspersed with lifting and lowering
operations, particularly as described in ~onfiguration
Figs. 6A-6F.
In one form of the invention, each of the
gripping elements may comprise a substantially tubular
member coupling a vacuum thereto, which may be selec-
tively applied. Alternatively9 each of the gripping
elements may include a grabber which comprises an
15elongated member extending along an axis perpendicular
to the Z axis having a barb extending from the tip clo-
sest to the surface 112a. In the latter embodiment,
the elongated member, or barbed needles, may be selac-
tively reciprocated in the Z direction under the
20control of controller 124.
FigO 5 shows an alternative embodiment 160'
for the assembly 160 of Fig. 1. In t~at Fig. 5,
corresponding elements are identified with identical
reference designations. In Fig. 5, assembly 160 inclu-
25des an elongated carrier assembly 210 having a cur-
vilinear central axis 212 extending along its length.
Axis 212 is substantially parallel to surface 112aO In
other embodiments, for example, where surface 112a is
not planar~ the axis 212 may not be para~lel to surface
30112a. In the present embodimentD the carrier assembly
210 includes a hinged housing (including sections 214,
216 and 217) and a flexible member 218 which is coaxial
with axis 212. One end of flexible member 218 is fixed
to housing segment 214 at point 220 and the other end
3sis slidably coupled to housing segment 218 at point
lZSB~86
~17-
2~2. Forcers 230 and 232 are adapted to applying
trans~erse forces -to member 218 at points between the
end points to control the curvature of axis 212. As
the forcers 230 and 232 control the orientation of the
5axis 212, each of the gripping elements may be selec-
tively displaced to provide the desired orientation of
the gripping elements. This embodiment in effect pro-
vides a cubic spline. In other embodiments, differlng
nu~bers of forcers may be used. In the assembly 160,
lOflexible cubic ~or higher-order) splines may be used to
position the gripping elements in any or all of
segments 180, 182 and 184. J
With either configuration 160 or 160', the
gripping elements may be selecti~ely driven to form a
15desired curvilinear contour over a portion of material
on the table 112a The ~ripping elements 180a, 182a
and 184a may be selectively lowered to the material on
the table 112a so that those gripping elements may be
activated to couple to tor "grab"~ the material at a
20corresponding curvilinear region of at least an upper-
most layer of the fabric on the surface 112a. To par
tially accomplish folding, the assembly 160 (or 160')
may then be raised in the Z direction in a manner
lifting that uppermost layer of the material.
The gripping element~ may then be translated
and/or rotated, and repositioned (to modify the cur-
vature of axis 212) so that the grabbed region of the
uppermost layer of material is repositioned to a selec-
tive location overlying a predetermined location over
30the surface 112a. The assembly 160 (or 160') may then
be lowered so that the lifted material is adjacent to
the surface 112a or overlying the material on surface
on 112a. All of this operation is under the control of
controller 124. The vacuum at surface 112a holds the
35material in position when that material is adapted to
surface 112a.
~5~
-18-
By selec-tively performing this operation over
desired curvilinear regions of the material, a desired
folding operation of the material may be a~tained.
Figs. 6A-6F show an exemplary folding sequence for
5asse~bling a sleeve. In that figure, a multilayer
fabric assembly is first sewn (with easing) along the
dotted line designatea 240 in Fig. 6Ao Tha~ assembly
includes an in-sleeve portion 242 and an out-sleeve
portion 244. Initially, the gripping elements 180a,
lOlB2a and 184a may be positioned along th~ heavy lined
portion of in-sleeve 242 denoted X in Fig. ÇA. That
contour may be then picked up and translated, reshaped
and lowered (and held with vacuum at the surface 112)
so that the contour X is reshaped and positioned at the
151Ocation shown in Fig. 6B. With this configuration,
the in-sleeve portion 242 has been folded about the
axis A-A. The elements 180a, 182a and 184a may then
release the material and the gripping elements may be
rearranged to match the contour denoted Y in ~ig. 6B.
20That portion of the material may then be picked up by
the gripping elements and the contour reshaped 50 that
it is then repositioned and shaped as shown in Fig. 6C,
with contour X overlapping contour Y0 As a result, the
material assembly is then folded along line B-B. Then,
25contour Y is released and the elements 180ag 182a and
184a are controlled to grip the contour Z on portion
244 shown in Fig. 6C. That contour is then lifted and
folded about line C-C as shown in Fig. 6D. Then con-
tour Z is released and the gripping elements are con-
30figured to grip contour W shown in Fig. 6D. Thatgripped contour is then folded about line D-D, as shown
in Fig. 6E. The sleeve assembly is then presented to
sewing head 140a.
By performing a tacking operation, the sewing
35head 140a as shown in Fig. 6F, the sleeve may be par-
tially assembled. The material may then be translated
~'~5~ P
back out to th~ surface 112a, and the contour T of the
out-sleeve 244 may be lifted by the assembly 160 tor
160') including elements 180a, 182a and 184a, and
transferred and reconfigured to unfold about line C C
5and match the con~ours X and Y as shown in Fig. 6F.
The out-sleeve is then released from elements 180a,
182a and 184a, and the folded assembly is then trans-
ferred by way of belts 120 and 150 to the sewing head
140a, where the elbow seam 240 is then joined. Thus,
lOwith this configuration, the sleeve shown in Fig. 6F is
assembled automatically under the control of controller
124. In all of these operations, the vacuum at surface
112a serves to hold material adjacent to that surface
in place.
Figs. 7 and 8 show the components of the
optical sensor system of the present embodiment. Fig.
7 includes an ~ptical sensor 117, and an illumination
system 118. In the present embodiment, the sensor 117
is in the form of a conventional television camera,
20although other image signal generating devices may be
used. The television camera 117 is supported so that
its optical axis 117a is substantially normal to the
surface 112a of the table 1120 The illumination system
118 includes a light source 260 and an associated beam
25splitter 262. The beam splitter is positioned on the
axis 117a between the camera 117 and surface 112a.
That beam splitter 262, for example a mirror type beam
splitter, is adapted to receive incident light from the
light source 260 along path 260a, reflect a portion of
30that light along optical axis 117a to the surface 112a,
and then to pass a portion of light reflected from sur-
face 112a ~or material positioned on that surface) back
along the axis 117a to the television camera 117.
With this illumination arrangement, common
35axis illumination is achieved for the system for use
~'~5~
-20-
~ith the r~tro-reflector configuration on surf~ce 112a.
The surface 112a may alternatively be forme~ by a
translucent material which is backlit, or by a
rluorescent surface (with appropriate filters for
5camera 117), although the retro-reflective common axis
illumination app~oach is the preferred form for the
present embodiment~
In operation, the camera 117 provides video
signals representa~ive af the image along the optical
lOaxis 117a of the surface 112 and any material thereon.
The retro~reflective surface 112a in effect provide a
high contrast background with respect to any material
on surface 112.
At t~e controller 124, these video siynals
15are processed to provide the position signals for use
with the automatic seam joining and folding control
portions of controller 124. Fig. 8 shows a block
diagram of a portion of controller 124 which performs
this function, in conjunction with the surface 112a,
20camera 117, and illumination source 118 and a video
monitor 266. In the present embodiment, the controller
124 includes a type LSI-11/23 microcomputer, manufac-
tured by Digital Equipment Corporation, Maynard,
Massachusetts. Fig. 8 also shows the interface between
25the camera and illumination system and ~he LSI-11/23
computer.
In operation, the functional block of
controller 124 in Fig. 8 performs edge detection of the
material against the background provided by surface
30112a. The edge detection is performed by differen-
tiating, or thresholding, the video signal generated by
the camera 117 as the camera scanning beam sweeps
across the image, marking the times within the sweep at
which ~here is a predetermined change in video signal
5~
intensity. These various "edge" times for each scan
line are provided to the computer upon request. ~y way
of example, where the camera 117 is an RCA type
TC1005/C49 came~a, the image of the table may be
5scanned in two seconds, and the edge information pro-
vid~d to the microcomputer, together with some data
checks and filtering on the raw data. Also within this
time frame, the microcomputer computes the area of a
material element in the field of view, the center of
lOthat area, and the angle the principal axis of that
material with respect to the a reference axis on sur-
face 112a. Appendices A and B show an exemplary
technique for performing these data processing
operationsO
With this configuration, the ~elevision
camera 117 provides an output signal from its video
amplifier circuitry and uses a separately generated
vertical sweep signal generated by a digital~to-analog
converter controlled by the microeomputer in controller
20124. With this arrangement, the D/A controlled ver-
tical sweep provides capability to increase a number o
scan lines and also to correct for non-linearity in a
relatively inexpensive camera yoke. The timing and
control portion of the controller 124 converts the
25event detectors put into a series of digital words that
contain a time of the event and the scan line number in
which the event occurred. With this type system, a
relatively high degree of edge resolution can be
achieved ~ithout requiring the conventional type pixel-
30image processing approach, and associated substantialcomputation cost and time. In alternative embodiments
of the invention, the overall seamed article assemblies
system may be configured with conventional type optical
sensing system, although at relatively high cost com-
35pared ~ith the particularly cost effective system shownin Figs. 7 and 8.
-~s~
-2~-
The invention may be embodied in other speci-
fic forms without departing from the spirit or essen-
tial characteristics thereof. The present embodiments
are therefore to be considered in all respects as
Sillustrative and not restrictive, the scope of the
invention being indicated by the appended claims rather
than by the foregoing description, and all change which
come within the meaning and range of equivalency of the
claims are therefore intended to be embraced therein.
,. ,
-~25~ 36
-23-
APPENDIX A
WorXpiece Recognition
A. Sensor Information
The camera scans the workpiece with respect to X-Y
5coordinates with the workpiece lying between X-
coordinates O and XN with upper and lower limits XL and
XH, respectively. Scan lines run parallel to Y-axis,
separated by ax. Scan information consists of y-
values for background-fabric transitions in the y-
lOdimension, where Yl is the left edge transition and
Y2 is the right edge transition in a scan line, The
distance between left edge and right edge transitions
for the ith scan line, ~Yi, is equal to Y2i-yli. The
differential area for the ith scan line, d~i equals
5~i~Yi' or ty2i-yli~ dx, or dydx.
B. Computation
Area A= ¦JdA
XN Y2~)
= ~ ~ dydx
O yl(X~
XN
lo [Y2(~) - yl~x)] dx
XN
= ~ æX o~Y2(X) ~ Yl~X)]
N
= ~x ~ Yi
i--O
~5~3~8~;
--24--
~entroid xc= - Jlx dA
A
XN y2(x)
r ~ x dydx
'Yl (x)
X~
f X[Y2 ( x ) -Yl ( x ) ~dx
A '~
~x XN
_ ~ xty2(x) - Yl(X)]
A X=O
~x N
A 1=O
CentroidYc ~ y dA
X~ y~x)
J I y dydx
A O Yl ~x)
~ 3 dx
A l 2 ¦Yl~X)
XN r y22(X~ yl~(x, ax
A O l 2
~x XN
= ~ ~ ~y22 ( X) - yl2 (
2A X=O
~x N
._ ~ (y22i - Y21i
2A i=O
. ~ ,~' ., ~ " .
:~ .
~S~8~j
--25--
Moment IXX - J~y2 dA
JN Y2(X) 2
O l(X)
XN r Y3 ~Y2~X)l
dx
Jo 3 yl(x
X~ fy23(x) - yl3(x) ~ dx
~x XN
5 = ~ Y23~x) - yl3(x) ]
3 X=O
~x ~ 3 3
Y2i ~ Yli)
3 i=O
Moment Iyy = JJx2 dA
XN x2 dydx
o Jyl(x)
= ~N x2 [y2(x)--yl(x)3 dx
O
XN
= ~ ~ X2 ~y2~X) ~ yl~x)]
X:o
N
~)~ Z X2i~Yi
~,:o
~'~5~
-26-
Mc)merlt I xy -Jrxy dA
XN Y2 ( x )
~l(X)
~N X ( ¦ ~x
XN ~Y22(X) ~ yl2(x)7 dx
= J Xl--~
= _ ~ x~y22(x~ _ yl2(x)]
2 X=O
x ~ ~ 22i - Y21i )
2 i=O
,
:: .
~;~513~
-27-
C. Principal Axis with Respect to Centroid Coordinate
Frame
-
The next step is to convert the moments from the
measurement into centroid frame, which is parallel to
5the original frame, but offset by ~le coordinates of
the computed centroid. The converted moments are:
xx = Ixx ~ ycA
Iyy - Iyy - x~cA
Ixy = Ixy - XcycA
~ = - tan~l[ x~ Iyy~
where a' corresponds to the angular offset of the w~rk-
piece centroid with respect to the principal axes.
D. Algorithm in BASIC
Below is shown all the BASIC language statemen~s
15that are necessary to implement the "moment
calculations". Only eight multiplications and nine
additions or subtractions are required in the high-
frequency loop. YL and YR represent the values for the
left and right profile, respectively, o the workpiece
20for each scan line.
100 FOR X = O TO XMAX STEP DX
110
200 READ YL, YR
i8~
-2~-
210 DY = YR - YL
220 YRSQ = YR ~ ~R
230 YLSQ = YL * YL
240 DYSQ = YRSQ - YLSQ
250 YRCUB = YRSQ * YR
260 YLCUB = YLSQ * YL
270
300 SUMl = S~Ml + DY
310 SUM2 - SUM2 + X * DY
320 SUM3 = SUM3 + DYSQ
330 SUM4 = SUM4 + YRCUB - YLCUB
340 SUM5 = SUM5 + X * X * DY
350 SUM6 = SUM6 ~ X * DYSQ
360
370 NEXT X
380
390
~00 A = DX * SUMl
410 XC = DX ~ SUM2/A
420 YC = DX * S~M3/(2 * A)
430
440 IXX - DX * SVM4 / 3
450 IYY = DX * SUM5
460 IXY = DX * SUM6 / 2
470
480 IXX - IXX - YC * YC * A
490 IYY = IYY - XC * XC * A
500 IXY = IXY - XC * YC * A
510 Theta = 0.5 * ATAN((-2*IXY)/(IXX-IYY))
APPENDIX B
Sleeve Data Base
The following information forms the "data base" for
the machine, before each sewing or folding operation,
for each sleeve size and styleO (Only the right or
35 1eft sleeve need be defined): ~
1. Nominal visual Area of worXpiece ~A)
~s~
-29-
2. Reasonable Tolerance for computed area
(+ ~A)
3. Centroia correction as function of ar~a
variation ( ~xc/~A ~ a Yc/ ~A )
4. With respect to a "sleeve" coordinate system
(i.e., origin at centroid, x-axis along
longitudinal principal axis):
A. Checkpoints (e.g. to identify left-
vs. right-hand piece, verify measure-
ment
- expected coordina~es of intercept of
centroid axes (~xc,Yc) and workpiece
- reasonable tolerance for any detected
edge (+ ~x, ~ ~y)
B. Seam "trajectory"
- coordinates of first stitch (eOg. off leading edge)
- number of individual stitches
- individual stitch segments
- ~x, ~y from previous stitch
-maximum sewing machine speed over segment
-easing rate over segment (standard material)
-gap stretching rate over segment ~standard
material)
-feeddogs up-down flag
-presser foot up-down flag
C. Folding "trajectory"
The transformation from "plotting" to "centroid" coor-
~ . .
~'
3~' ` '`
-30-
dinates involves a ~xc,Yc) offset, followed by a rota-
tion by angle 0:
r coS~ -Sin~ 1
(X)C= r(X)p-(xc~yc)]~ ~
Sin~ Cos9
The transformation relationship for the stitch segments
5(Si - sj) is slightly different:
r COs0 -sine -
( Q S)c = ( ~s)p I
L Sine cOse ,
To provide measurement and a First Reasonableness
Test where both the workpiece and table coordinate
frame visible within the camera field-of-view, the scan
lOalgorithm is as follows:
1. For each scan linei
d Yl, Y2 3 ~ Yn tn varies with shape)
-If (Y2 -Yl) ~ ~ or (Yn~Y~ or
if (Y3 -Y2)~ ~ or (Yn l~Yn-2)< ~ then
- increment a count0r and use previous ~ Yi
-For j = 3 to n-2, step 2
- ~Yi = ~Yi ~ ~Yj~l ~ Yj)
~Accumulate y's or Area computation.
~ .
~'~5~
-31-
2. Compute Area as ~x ~ ~ Yi
i=l
3. Compare Ameas with ADB ~ ~ ADB
If not in interval, repeat measurement and
incremént counter. If counter is beyond a
threshold, alert operator.
E'or each scan line, partial sums can be accumulated for
the centroid and principal angle:
For i = 1 to M
-Accumulate (i ~x) ~ Yi ~For xc)
.
xi
-Accumulate (i X)2 ~yi ~For Iyy)
x2
-For j = 3 to n-2, step 2
-Accumulate (y2j+l _ y2j~ ~For Yc~
-Accumulate (y3 ~,
j~l J) ~For IXx)
~z~
-32-
-Accumulate (i ~x) ~y2~ y2j3 (For Ixy)
Using those partial sums, the centroid and
principle angle can easily be calculated using the
algorith~ described in Appendix A, that is:
N N n-2
xc = - ~ xi Yi, Yc = ~ ~ ~ 3 ~Y j~i ~ Y j)
i=l i=l
To pro~ide a Second Reasonableness Test and
Right- vs. Left-Piece identification, even if the
detected area, centroid, and principal angle seem
reasonable, there may still be ~ome ambiguity whether a
lO"righthand" or "lefthand" piece was loaded and scanned.
Unless the piece is exactly symmetrical about
its two principal axes, the four predicted x, y inter-
cepts with the piece edges can be checked to 1) ascer-
tain whether a right- or left-handea piece was loaded
15and 2) perform a final reasonableness test.
In the present form, only "mirror" loading
about the piece longitudinal axis is allowed; i.e.,
only the y+ and y intercepts str used to determine
whether a right- or left~-handed piece was loaded. If
20the x+, x_ are not confirmed, the piece is rejected (or
centroid corrected). Thus t the piece can not be loaded
backwardsO
~51~ 6
-33-
Also, if the predicted XC, Yc in~ercepts are
"close" and consistent with a slightly larger or
smaller area, the centroid and principal angle is
adjusted slightly to allow for miscut pieces or unpre-
5dictable manual folding variations.
An exemplary algorithm is as follows:
1. Determine if predictable intercepts y~, y
can be confirmed with actual camera data.
a. convert the x-components ¦in table
coordinates) of y~ and y to a par-
ticular scan line
number (i.e., i+, i_~.
b. convert the y-components (in table
coordinates~ of y+ and y to a particular
camera y-displacement (i.e., ~ y+, y ).
c. Look at the raw camera data (or repeat
the scan) for a y+ value (i.e., table-
piece transition~ along scan line i~
and a y value along scan line i_. Use
~o a reasonable y for success criterion.
d. If concurrence results, proceed to Step 2.
If not, swap y+ and y_ and repeat Steps
la-lc (look for concurrence for mirror-image
around x axis).
e. If concurrence results from swapping the
y's, then change the sign of the y-component
for all trajectory points (i.e., start end
of seam and y $or each stitch~.
f. If no concurrence again, ~hen stop and
inform operator.
-34-
. Repeat Steps la-lc or x+ and x . If
concurrence, preceed to Step 3, if not,
stop and inform operator.
3. Correct the trajectory for the small
differences between predicted and measured
intercept values, using one of the following
rules:
a. Xc = Xc ~ a xc/ ~ ~
YC Yc ~ ~Yc/ a ~ A
e = e + ae/ ~ ~ A
where ~x~/ a ~ A, etc. are empirical
values from the data base.
Then use the new XC, Yc~ and e values to
retransform the æewing/folding trajectory
from centroid to table coordinates.
b. Use the (X~(act~a~ +(predict))
value to correct all positive x-
coordinates of trajectories (i.e.,
beginning and ending of seams and
folds, but not ~ x,~y of stitches).
This, if the detect~d x~ point falls
further from the centroid than the
predicted x+ point, "expand" the
beginning or end of the trajectory
further away from the centroid in the
~x direction.
Repeat similarly for the -x, +y, and -y
directions~
The last step prior to ~ewing is to transform the
30stitch trajectory from table into sewing module
(control~ coordinates.
~l~58~6
-35-
It's preferred to define the x sewing axis as ori-
ginating from ~he sewing gap so that the velocity of
the workpiece may change as it crosses the gap, due to
different main motor and stretching motor rates. In
50rder to simplify sewing "navigation" equations,
- (XTS, -YTS~ is subtracted from every non-stitch
segment (i.e., non x, y) coordinate of the tra-
jec~ory. This converts the centroid and seam
start-end points into sewing coordinates.
- The sewing translator is slewed to the
y-coordinate of the start of the seam.
- Simultaneously, the belts (and workpiece) are
moved, continually keeping track Df the x-
coordinate of the centroid (or the first stitch)
in sewing coordinates as it decreases toward zero
(approaches the needle).
n (Xc) sewing reaChes the value of
(Sl(x) _ Xc) table
l(x)sewing)
(i.e., the start of ths first stitch passes under
the needle), and/or the fabric is detected under
the needle, then sewing commences by issuing ~x,
~ y commands to the belts and translator from
the sewing trajectory.
- The x-position of the centroid (or first stitch)
is continually be updated, so t~lat the piece can
be brought back to the original position on ~he
loading table (or taken to the proper position on
the folding table) after sewing is completed~
- ~hen the centroid (or first stitch) passes across
the sewing gap, its speed is goverened by ~he
main motor and the stretching motor.
:' '
