U.S. patent application number 10/164992 was filed with the patent office on 2002-12-05 for apparatuses and methods for non-destructive inspection.
Invention is credited to D'Ambrosio, Karl V..
Application Number | 20020181650 10/164992 |
Document ID | / |
Family ID | 26916212 |
Filed Date | 2002-12-05 |
United States Patent
Application |
20020181650 |
Kind Code |
A1 |
D'Ambrosio, Karl V. |
December 5, 2002 |
Apparatuses and methods for non-destructive inspection
Abstract
An automated real-time, non-destructive inspection system usable
to inspect a selected structure for a defect and visually identify
a defect's location. In one embodiment, the inspection system is an
x-ray inspection system mounted to an articulatable robot arm
movable relative to the selected structure. A support system is
attached to the articulatable robot arm that supports an imaging
source on a first support portion and a detector panel on a second
support portion spaced apart from the first support portion. A
visual targeting system configured to identify where an imaging
beam axis intersects the selected structure is positioned adjacent
to the imaging source. The inspection system is configured to
maneuver the imaging source and detector panel around the selected
structure such that the desired areas on the selected structure may
be fully inspected without having to reposition the selected
structure.
Inventors: |
D'Ambrosio, Karl V.;
(Seattle, WA) |
Correspondence
Address: |
PERKINS COIE LLP
PATENT-SEA
P.O. BOX 1247
SEATTLE
WA
98111-1247
US
|
Family ID: |
26916212 |
Appl. No.: |
10/164992 |
Filed: |
June 6, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10164992 |
Jun 6, 2002 |
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09732238 |
Dec 7, 2000 |
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60221848 |
Jul 28, 2000 |
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Current U.S.
Class: |
378/43 |
Current CPC
Class: |
G01N 23/04 20130101 |
Class at
Publication: |
378/43 |
International
Class: |
G21K 007/00 |
Claims
I claim:
1. A real-time, non-destructive inspection system usable to inspect
a selected structure, comprising: an articulatable robot arm
moveable relative to the structure; a support system attached to
the articulatable robot arm, the support system having first and
second support portions spaced apart from each other defining a
space therebetween; an imaging source attached to the first support
portion of the support system, the imaging source being in a first
imaging source position relative to the structure; and an imaging
detector panel attached to the second support portion of the
support system and spaced apart from the imaging source, the
imaging detector panel being in a first imaging detector panel
position relative to the structure, the imaging source and imaging
detector panel configured to provide an image of the structure, the
imaging source and detector panel being moveable relative to the
structure to second imaging source and detector panel positions
relative to the structure, respectively, while the image of the
structure is being provided.
2. The real-time, non-destructive inspection system of claim 1
wherein the imaging source and imaging detector panel are moveable
with the support system as a unit relative to the structure while
the image of the structure is being provided.
3. The real-time, non-destructive inspection system of claim 1
wherein at least one of the imaging source and the imaging detector
panel is moveable relative to the other while the image of the
structure is being provided.
4. The real-time, non-destructive inspection system of claim 3
wherein the imaging source is adapted to project an imaging source
beam along an imaging beam axis, and at least one of the imaging
source and the imaging detector panel is moveable toward or away
from the other substantially along the imaging beam axis to adjust
a distance between the imaging source and the imaging detector
panel.
5. The real-time, non-destructive inspection system of claim 3
wherein the imaging source is adapted to project an imaging source
beam along an imaging beam axis, and at least one of the imaging
source and the imaging detector panel is moveable relative to the
other in a direction substantially perpendicular to the imaging
beam axis.
6. The real-time, non-destructive inspection system of claim 1
further comprising a structure positioning system configured to
movably support the structure relative to the imaging source and
the imaging detector panel, and wherein the structure is moveable
with the structure positioning system relative to the imaging
source and the imaging detector panel while the image of the
structure is being provided.
7. The real-time, non-destructive inspection system of claim 1
wherein the imaging source is an x-ray source and the imaging
detector panel is an x-ray detector panel.
8. The real-time, non-destructive inspection system of claim 1
wherein the support system further comprises a track beam adapted
to connect to the articulatable robot arm, wherein the first
support portion has a first coupling end and a first distal end,
the first distal end supporting the imaging source and the first
coupling end being adjustably connected to the track beam, wherein
the second support portion has a second coupling end and a second
distal end, the second distal end supporting the imaging detector
panel and the second coupling end being adjustably connected to the
track beam, and wherein the first and second support portions are
movable relative to each other along the track beam.
9. A real-time x-ray inspection system usable to inspect a selected
structure, comprising: an articulatable robot arm moveable relative
to the structure; a support system attached to the articulatable
robot arm, the support system having first and second support
portions spaced apart from each other defining a space
therebetween; an x-ray source attached to the first support
portion, the x-ray source being in a first x-ray source position
relative to the structure; and an x-ray detector panel attached to
the second support portion and spaced apart from the x-ray source,
the x-ray detector panel being positioned in a first x-ray panel
position relative to the structure, the x-ray source and x-ray
detector panel configured to provide an x-ray image of the
structure, the x-ray source and x-ray detector panel being movable
relative to the structure to second x-ray source and x-ray detector
panel positions relative to the structure, respectively, while the
x-ray image of the structure is being provided.
10. The real-time x-ray inspection system of claim 9 wherein the
x-ray source and x-ray detector panel are moveable with the support
system as a unit relative to the structure while the x-ray image of
the structure is being provided.
11. The real-time x-ray inspection system of claim 9 wherein at
least one of the x-ray source and the x-ray detector panel is
moveable relative to the other while the x-ray image of the
structure is being provided.
12. The real-time x-ray inspection system of claim 11 wherein the
x-ray source projects an x-ray beam along an x-ray beam axis, and
at least one of the x-ray source and the x-ray detector panel is
moveable toward or away from the other substantially along the
x-ray beam axis to adjust a distance between the x-ray source and
the x-ray detector panel.
13. The real-time x-ray inspection system of claim 9 further
comprising a structure positioning system configured to moveably
support the structure relative to the x-ray source and the x-ray
detector panel, and wherein the structure is moveable with the
structure positioning system relative to the x-ray source and the
x-ray detector panel while the x-ray image of the structure is
being provided.
14. The real-time x-ray inspection system of claim 13 wherein the
structure positioning system is a turntable.
15. The real-time x-ray inspection system of claim 13 wherein the
structure positioning system is a track.
16. A real-time, non-destructive inspection system usable to
inspect a selected structure and visually identify a location of a
selected portion of the structure, comprising: a support system
having first and second support portions spaced apart from each
other defining a space therebetween sized to receive the structure
therein; an imaging source attached to the first support portion,
the imaging source adapted to project an imaging source beam along
an imaging beam axis; an imaging detector panel attached to the
second support portion of the support system and spaced apart from
the imaging source, the imaging source and detector panel being
moveable as a unit relative to the structure while providing an
image of the structure; and a visual targeting system having a
first line generator positioned adjacent to the imaging source and
positioned to project a first light plane and a second line
generator positioned adjacent to the imaging source and positioned
to project a second light plane intersecting the first light plane
along the imaging beam axis, the second light plane being
non-parallel to the first light plane.
17. The real-time, non-destructive inspection system of claim 16
wherein the first and second line generators are laser line
generators.
18. The real-time, non-destructive inspection system of claim 16
wherein the first and second line generators are positioned such
that the second light plane is orthogonal to the first light
plane.
19. A method for determining an axial distance between an imaging
source and a selected portion of a structure, the structure being
positioned between the imaging source and an imaging detector panel
spaced apart from the imaging source, the method comprising:
detecting an image of the selected portion on the imaging detector
panel when the imaging source is in a first source position;
determining a first image position of the selected portion image on
the detector panel when the imaging source is in the first source
position; determining an axial distance between the imaging source
and the imaging detector panel when the imaging source is in the
first source position; moving the imaging source laterally relative
to the selected portion to a second source position; determining a
lateral distance moved by the imaging source between the first
source position and the second source position; determining a
second image position of the selected portion image on the detector
panel when the imaging source is in the second source position;
determining a lateral distance moved by the selected portion image
on the detector panel relative to the selected portion between the
first image position and the second image position; and determining
the axial distance between the imaging source and the selected
portion based on the axial distance between the imaging source and
the imaging detector panel, the lateral distance moved by the
imaging source, and the lateral distance moved by the selected
portion image on the imaging detector panel.
20. The method of claim 19 wherein detecting an image of the
selected portion on the imaging detector panel comprises detecting
an x-ray image of the selected portion on an x-ray image detector
panel.
21. The method of claim 19 wherein determining the axial distance
between the imaging source and the selected portion includes:
determining a product by multiplying the axial distance between the
imaging source and the imaging detector panel by the lateral
distance moved by the imaging source between the first source
position and the second source position; and dividing the product
by a sum of the lateral distance moved by the imaging source
between the first source position and the second source position
plus the lateral distance moved by the selected portion image on
the detector panel between the first image position and the second
image position.
22. A method for determining an axial distance between an imaging
source and a selected portion of a selected structure, the selected
structure being positioned between the imaging source and an
imaging detector panel spaced apart from the imaging source, the
method comprising: detecting an image of the selected portion on
the imaging detector panel when the imaging source is in a first
source position; determining a first image size of the selected
portion image when the imaging source is at the first source
position; moving the imaging source axially relative to the
selected portion to a second source position; determining a second
image size of the selected portion image when the imaging source is
at the second source position; determining an axial distance moved
by the imaging source between the first and second source
positions; and determining the axial distance between the imaging
source at the first source position and the selected portion based
on the first image size, the second image size, and the axial
distance moved by the imaging source.
23. The method of claim 22 wherein detecting an image of the
selected portion on the imaging detector panel comprises detecting
an x-ray image of the selected portion on an x-ray detector
panel.
24. The method of claim 22 further comprising: determining a
product by multiplying the axial distance moved by the imaging
source by the second image size; and dividing the product by the
difference between the first image size and the second image size.
Description
TECHNICAL FIELD
[0001] The present invention is directed to apparatuses and methods
for non-destructive inspection, and more particularly, to automated
real-time, non-destructive inspection apparatuses and methods.
BACKGROUND OF THE INVENTION
[0002] Real-time x-ray machines for detecting flaws or defects in
metallic structures are known. A real-time x-ray machine can
provide a continuous x-ray image of a structure moving across the
x-ray machine's field of view. Conventional real-time x-ray
machines are typically based on cartesian motion control systems
that allow translational movement of an x-ray source and imaging
panel in one or two degrees of freedom relative to the stationary
structure being inspected. Such systems are inherently limited in
flexibility, and often cannot adequately image all desired areas of
complex structures without repositioning of the structures relative
to the x-ray source. For large or awkward structures, this
repositioning to ensure accurate imaging may prove time consuming
and labor intensive. In addition, this repositioning may also
require expensive fixturing or heavy-duty motion systems, with
different structures requiring different item-specific
fixtures.
[0003] To maintain the integrity of the resulting x-ray image,
conventional x-ray systems typically require that the plane of the
imaging panel be perpendicular to, and at least approximately
centered on, the x-ray beam axis. Significant problems or
difficulties may be encountered if the x-ray source and imaging
panel are allowed to move independent of each other off the x-ray
beam axis. As one solution to this problem, Xylon Corporation
produces a real-time x-ray system having a rigid C-frame that holds
the x-ray source and imaging panel in a fixed relationship to each
other during motion to ensure proper imaging. The C-frame, however,
is only free to translate in two degrees of freedom relative to the
part, and thus repositioning of structures is often required for
comprehensive x-ray inspections.
[0004] When an unacceptable flaw or defect is found in a structure
through x-ray inspection, it is important to identify the actual
location of the defect on the structure so that a subsequent
inspection or repair can be effectively carried out. One difficulty
with conventional real-time x-ray systems is that the axial
location of the defect along the x-ray beam axis may be difficult
to ascertain for structures having substantial depth or multiple
portions along that axis. For example, when inspecting a
circumferential weld around a cylindrical duct where the x-ray beam
axis is positioned parallel to the weld plane, it may be difficult
to determine if an observed defect in the weld exists on the near
side of the duct or the far side of the duct relative to the x-ray
source. If the axial location of the defect cannot be sufficiently
determined, then either the x-ray machine or the structure must be
repositioned for further x-ray imaging in an effort to ascertain
the defect's actual location.
[0005] The size of defects in metallic parts is often extremely
small and non-visible to the human eye. In addition, the lack of
reference points on the surface of a structure often make it
difficult to correlate the location of a defect as seen on the
x-ray image display screen to a precise location on the part. For
these reasons, it may be difficult to determine the precise lateral
location of a defect on the surface of a part, even when the
general axial location of the defect can be ascertained.
[0006] By placing a structure for inspection between the x-ray
source and the imaging panel, any defect observed will be projected
onto the imaging panel in a magnified size. Another difficulty with
conventional real-time x-ray systems is that even when the axial
and lateral location of the defect can be ascertained, the actual
size of the defect is often difficult to determine with any
precision because of this geometric magnification. Determining the
size of the defect is important, however, as it will dictate either
the acceptability of the structure or the nature of the repair
which must be carried out. Determination of the defect's size in
conventional systems, however, has typically required physical
measurements by an operator using manual measuring devices. Not
only is this a tedious, labor intensive exercise, but it can also
result in a somewhat inexact determination of the size of the
defect.
SUMMARY OF THE INVENTION
[0007] The present invention provides a real-time, non-destructive
inspection system usable to inspect a selected structure for
defects. The inspection system is also usable to visually identify
a defect's location on the structure. One embodiment of the
invention provides an articulatable robot arm movable relative to
the structure. A movable support system is attached to the
articulatable robot arm and has first and second support portions
spaced apart from each other defining a space therebetween sized to
receive the structure being inspected. An imaging source is
attached to the first support portion and is adapted to project an
imaging beam along an imaging beam axis. An imaging detector panel
is attached to the second support portion and is spaced apart from
the imaging source. The imaging detector panel is positioned at
least approximately perpendicular to, and intersecting, the imaging
beam axis. The imaging source and detector panel are configured to
provide images of the structure. A display screen is coupled to the
imaging detector panel to display the images of the structure in
real-time as the structure is being inspected. Accordingly, the
inspection system of the present invention can fully inspect the
selected structure by maneuvering the imaging source and imaging
detector panel relative to the structure while providing images of
the structure to the operator in real-time.
[0008] Another embodiment of the invention includes a visual
targeting system adjacent to the imaging source and configured to
identify where the imaging beam axis intersects the structure
undergoing inspection. The visual targeting system in one
embodiment has a first line generator positioned adjacent to the
imaging source and configured to project a first light plane
collinear with the imaging beam axis. A second line generator is
also adjacent to the imaging source and configured to project a
second light plane collinear with the imaging beam axis and
non-parallel to the first light plane. The intersection of the
first and second light planes is collinear with the imaging beam
axis. In the one embodiment, the intersecting light planes create
illuminated cross-hairs that visually indicate the imaging beam
axis location on the selected structure to facilitate finding a
defect's location on the structure.
[0009] Yet another embodiment of the invention provides a method
for determining the size of a defect in the selected structure by
determining a distance between the imaging source and the defect.
The method comprises providing the imaging source in a first source
position with an image of the defect on the detector panel being in
a first image position. An axial distance between the imaging
source and the imaging detector panel is determined when the
imaging source is in this first source position. The imaging source
is moved to a second source position with the image of the defect
on the detector panel being moved laterally to a second image
position. The distance moved by the imaging source between the
first and second source positions, and the corresponding distance
moved by the image of the defect on the detector panel between the
first and second image positions, is determined. The distance
between the imaging source and the defect is then determined based
on the distance between the imaging source and the imaging detector
panel, the distance moved by the imaging source, and the
corresponding distance moved by the image of the defect. To
determine the actual size of the defect, the magnification of the
defect's image is determined by the ratio of the distance between
the imaging source and the imaging detector panel to the distance
between the imaging source and the defect. Accordingly, the size of
the defect is then determined by dividing the defect's image size
by the magnification of the defect's image.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is an isometric view of an automated real-time,
non-destructive inspection system in accordance with an embodiment
of the invention.
[0011] FIG. 2 is an enlarged side elevation view taken
substantially along lines 2-2 in FIG. 1 illustrating an imaging
system and a support system of the inspection system, the imaging
and support systems are shown in solid lines in a first position
and are shown in phantom lines in a displaced second position.
[0012] FIG. 3 is a front elevation view of a display screen showing
a first image of a selected structure when the imaging system of
FIG. 2 is in the first position.
[0013] FIG. 4 is a front elevation view of the display screen
showing a second image of the selected structure when the imaging
system of FIG. 2 in the second position.
[0014] FIG. 5 is an enlarged isometric view of a targeting system
of the imaging system of FIG. 1.
[0015] FIG. 6 is a schematic top view of the imaging system of FIG.
1 with the imaging source shown in solid lines in a first position
and shown in phantom lines in a displaced second position.
[0016] FIG. 7 is a front elevation view of the display screen of
FIG. 3 showing an image of the defect when the imaging source of
FIG. 6 is in the first position.
[0017] FIG. 8 is a front elevation view of the display screen of
FIG. 3 showing an image of the defect when the imaging source of
FIG. 6 is in the second position.
[0018] FIG. 9 is a schematic top view of an alternate embodiment of
the imaging system of FIG. 1 with the imaging source and detector
panel shown in solid lines in first positions and shown in phantom
lines in displaced second positions.
[0019] FIG. 10 is a front elevation view of the display screen of
FIG. 3 showing an image of the defect when the imaging source and
detector panel of FIG. 9 are in their first positions.
[0020] FIG. 11 is a front elevation view of the display screen of
FIG. 3 showing an image of the defect when the imaging source and
detector panel of FIG. 9 are in their second positions.
[0021] FIG. 12 is a schematic top view of an alternate embodiment
of the imaging system of FIG. 1 with the imaging source shown in
solid lines in a first position and shown in phantom lines in a
displaced second position.
[0022] FIG. 13 is a front elevation view of the display screen of
FIG. 3 showing an image of the defect when the imaging source of
FIG. 9 is in the first position.
[0023] FIG. 14 is a front elevation view of the display screen of
FIG. 1 showing an image of the defect when the imaging source of
FIG. 9 is in the second position.
DETAILED DESCRIPTION
[0024] In the following description, certain specific details are
set forth in order to provide a thorough understanding of various
embodiments of the invention. The present disclosure describes
automated real-time, non-destructive inspection systems. The
disclosure also describes methods for using the inspection systems
in locating selected portions of structures, such as flaws and
defects, and determining the size of those portions. Many specific
details of certain embodiments of the invention are set forth in
the description and in FIGS. 1-11 to provide a thorough
understanding of these embodiments. One skilled in the art will
understand, however, that the present invention may have additional
embodiments, or that the invention may be practiced without several
of the details described below. In other instances, well-known
structures associated with inspection systems have not been shown
or described in detail to avoid unnecessarily obscuring the
description of the embodiments of the invention.
[0025] FIG. 1 is an isometric view of an automated real-time,
non-destructive inspection system 100 in accordance with an
embodiment of the invention for inspection of a selected structure
or structure 140, such as a welded component of a larger assembly.
The automated real-time, non-destructive inspection system 100
("inspection system 100") has an imaging system 120 mounted to a
support system 121. The support system 121 is in turn mounted to an
articulatable robot 110 configured for movement of the support
system, and hence the imaging system 120, relative to the structure
140. A display screen 132 is coupled to the imaging system 120 to
graphically display images of the structure 140 in real-time as the
structure is being inspected. In one aspect of this embodiment, the
structure 140 is held in a stationary position, and the inspection
system 100 moves relative to the structure to obtain real-time
images of the structure from different angular perspectives. A
computer 130 and a manual control system 131 are operatively
coupled to the robot 110, the support system 121, and the imaging
system 120 so that operation of the robot, support system and
imaging system can be effectuated either automatically according to
a computer program or manually by an operator.
[0026] The imaging system 120 includes an imaging source 125 and a
detector panel 127 spaced apart from the imaging source. The
imaging source 125 projects an imaging beam, such as an x-ray beam
or the like, toward the detector panel 127 along a beam axis 128.
The detector panel 127 is positioned along the imaging beam axis
128 a selected distance from the imaging source 125. The detector
panel 127 has a planar detector portion 129 oriented substantially
perpendicular to the imaging beam axis 128. In one embodiment, the
imaging system 120 is an x-ray-imaging system. In one aspect of
this embodiment, the x-ray-imaging source 125 is a Hamamatsu 150 KV
microfocus x-ray tube, and the detector panel 127 is a Varian VIP-9
amorphous silicon x-ray detector. In other aspects of this
embodiment, other x-ray imaging sources 125 and other x-ray
detector panels 127, such as amorphous selenium or image
intensifiers, may be used. In other embodiments, other types of
imaging energy sources that can penetrate the structure 140 may be
used as the imaging source 125, including electromagnetic or sonic
waves. An imaging energy detector panel should be used that
corresponds to the particular type of energy generated by the
imaging energy source. For visible and ultraviolet light,
charge-coupled device (CCD) cameras may be used. In the case of
sonic waves, a vibration-sensitive piezo electric detector may be
used as the imaging element in place of the detector panel 127. In
yet another embodiment, a heat source may be applied to the
structure 140 and infrared video cameras may be used to detect
defects in the part.
[0027] As best seen in FIG. 1, the imaging system 120 of the
illustrated embodiment is mounted on the support system 121. The
support system 121 includes a source support arm 124, a track beam
122, and a panel support arm 126. The imaging source 125 is mounted
to the source support arm 124 and the detector panel 127 is mounted
on the panel support arm 126. Both the source support arm 124 and
the panel support arm 126 are movably engaged with the track beam
122 such that their movements are restricted in all directions
except along the length of the track beam 122. Accordingly, the
imaging source 125 and the detector panel 127 can translate toward
or away from each other along an axis 152, but independent lateral
motion relative to the support arms and each other is precluded. In
an alternate embodiment, however, the imaging source 125 can
independently translate laterally relative to the source support
arm 124 and the detector panel 127 for short distances along an
axis 153 perpendicular to the track beam 122 by way of a roller
coupling 123 that movably attaches the imaging source 125 to the
source support arm. In another alternate embodiment, the detector
panel 127 can be movably attached to the panel support arm 126,
such as by a roller coupling or the like, so that the detector
panel can also translate laterally relative to the panel support
arm and the imaging source 125 in a direction perpendicular to the
track beam 122.
[0028] The support system 121 of the illustrated embodiment of FIG.
1 is movably coupled to the articulatable robot 110 for movement of
the imaging system 120 as a unit relative to the structure 140. The
robot 110 includes an articulatable head 112, an articulatable arm
111, and a supporting base 113. A bracket 114 on the track beam 122
mounts the support system 121 to the articulatable head 112, and
the articulatable head 112 is in turn movably connected to the
articulatable arm 111. In one embodiment, the robot 110 is an
ABB6400 250 Kg Wrist Capacity Robot with S4C controller, coupled to
an ABB IRTB 6002S robot track. In other embodiments, other suitable
robots can be used. A wire harness assembly 115 for transmitting
power and data to and from the imaging system 120 is suitably
attached to the articulatable arm 111 in such a way that the wire
harness will not inhibit movement of the support system 121, the
imaging system or the robot 110.
[0029] The computer 130 can be used to automatically control the
motion of the robot 110, support system 121, and the imaging system
120 relative to the selected structure 140 being examined. In this
embodiment, the computer 130 is configured to control these systems
via a suitable computer program or routine. Alternatively, motion
of these systems can be accomplished by an operator using the
manual controls 131 coupled to the robot 110, support system 121,
or imaging system 120. As the imaging system 120 is moved relative
to the structure 140, a real-time display of an image of the
structure being inspected is provided from the detector panel 127
to the display screen 132, which a user can view during an
inspection procedure. In one aspect of this embodiment, the
graphical display on the display screen 132 can contain
computer-generated cross-hairs 134 (shown in FIG. 1) that represent
the location of the imaging beam axis 128 relative to the structure
140 being viewed. In another aspect of this embodiment, the display
screen 132 can include two Matrox PC-based frame grabber cards used
in conjunction with a Barco 5 megapixel medical grade video display
monitor. In other embodiments, other software and other display
monitors can be used to provide the real-time display of the
structure during inspection.
[0030] In one embodiment, a track assembly 162 optionally including
a turntable 160 is provided between the source support arm 124 and
the panel support arm 126 to support the structure 140 in a
selected position relative to the imaging beam axis 128. The track
assembly 162 and/or the turntable 160 is configured to move the
structure 140 relative to the ground, while the robot 110 moves the
imaging system 120 relative to the structure and the ground. The
track 162 and/or turntable 160 may be used when translation or
rotation, respectively, of the structure 140 relative to the
imaging system 120 would facilitate the inspection process. The
track 162, oriented, as shown in FIG. 1, would permit the structure
140 to be translated along the axis 153 relative to the ground and
the imaging system 120. The track 162 can be oriented at other
angles if advantageous. Similarly, rotation of the turntable 160
would permit rotation of the structure 140 about an axis 151
relative to the ground and the imaging system 120. The track 162
and/or turntable 160 can be operatively coupled to the computer 130
for automated structure orientation or to coordinate motion of the
structure with motion of the imaging system 120. Use of the track
162 and/or turntable 160 may provide certain advantages for the
inspection of larger parts.
[0031] The inspection system 100 is capable of moving the imaging
system 120 in a full six degrees of motion while providing a
real-time image on the display screen 132 of the structure 140
under inspection. The imaging beam axis 128 remains substantially
perpendicular to, and generally centered on, the detector panel 127
during such movement. In one aspect of this embodiment, the
articulatable head 112 can impart rotation to the imaging system
120 about the axes 151, 152 and 153, respectively. Translation of
the imaging system 120 along these axes can be accomplished by
movement of the robot 110 and/or the articulatable arm 111 relative
to the base 113. As mentioned above, the imaging source 125 and
detector panel 127 are also capable of moving toward or away from
each other along the track beam 122. It will be apparent to those
of skill in the art that the foregoing translational and rotational
motions of the imaging system 120 provide a very high degree of
control and accuracy to the inspection process.
[0032] An understanding of a typical inspection procedure using the
inspection system 100 can be gained with reference to FIG. 1 and
the following example. To inspect a circumferential weld 141 in the
structure 140, for example, the robot 110 positions the imaging
system 120 so that the imaging beam axis 128 at least approximately
intersects the weld 141. An operator can use the display screen 132
to confirm that the imaging system 120 is properly aligned, as the
computer-generated cross-hairs 134 will indicate the location of
the imaging beam axis 128 relative to the weld or other portion of
the structure 140 being viewed. The robot 110 then moves the
imaging system 120 along a prescribed path around the structure
140, the path being selected based upon the areas of the structure
being inspected. For example, if the circumferential weld 141 on
the structure 140 is being inspected, the robot 110 rotates the
imaging system 120 about the axis 151 as the imaging beam axis 128
maintains alignment with the weld 141, until the entire weld 141
has been imaged and inspected. An image of the weld 141 is
displayed on the display screen 132 for the operator to view
real-time as the imaging system 120 moves around the structure 140.
If the image discloses the defect 142, the inspection process can
be temporarily stopped while the defect's location is marked on the
structure for subsequent inspection or repair. A vertical weld 145
can be similarly inspected by translation of the imaging system 120
along the axis 151. The ability of the inspection system 100 to
fully inspect the circumferential weld 141 or the vertical weld 145
obviates the need to reposition the structure 140 at any time
during the inspection. As will be apparent to those of skill in the
art, virtually any structure orientation can be inspected using the
inspection system 100.
[0033] FIG. 2 is an enlarged side elevation view of the imaging
system 120 and the support system 121 taken substantially along
lines 2-2 in FIG. 1, in accordance with an embodiment of the
invention. A fitting 233 at a top portion of the source support arm
124 extends into an elongated channel 221 running lengthwise in the
track beam 122 such that the fitting movably engages the track
beam. A fitting 235 on the top portion of the panel support arm 126
similarly extends into the channel 221 and movably engages the
track beam. A drive screw 282 mates to a drive motor 283 mounted to
the track beam 122, and to a threaded coupling 289 attached to the
fitting 233 of the source support arm 124. A drive screw 284
similarly mates to a drive motor 285 mounted to the track beam 122,
and to a threaded coupling 287 attached to the fitting 235 of the
panel support arm 126.
[0034] As mentioned above, the source support arm 124 and the panel
support arm 126 can move toward or away from each other as
indicated by arrows 271 and 272, respectively. Motion of the source
support arm 124 and panel support arm 126 in directions 271 and 272
is effectuated by the drive motors 283 or 285, respectively,
turning the drive screws 282 or 284, respectively. In the
illustrated embodiment, the drive motors 283 and 285 are
synchronized so that the source support arm 124 and panel support
arm 126 move simultaneously. The independence of the drive motors
283 and 285, however, allows optional selection of either
independent or synchronized motion of the imaging source 125 and
the detector panel 127. Alternatively, a coupling 286 can be used
to couple the drive screw 282 to the drive screw 284 to permit only
synchronized motion of the imaging source 125 and detector panel
127, either together or away from each other. As will be
appreciated by those of skill in the art, in an alternate
embodiment a single drive motor, for example either drive motor 283
or 285, can be used. In this embodiment, the drive screws 282 and
284 will be coupled together and both driven by the single drive
motor to effectuate synchronized motion of the imaging source 125
and detector panel either toward or away from each other along the
track beam 122.
[0035] In addition to motion along the track beam 122, in an
alternate embodiment the imaging source 125 is also capable of
limited movement laterally relative to the source support arm 124
in directions perpendicular to the track beam 122 via the roller
coupling 123, thereby allowing for lateral adjustment of the
imaging source 125 relative to the detector panel 127. Similarly,
in an alternate embodiment the detector panel 127 is also capable
of limited movement laterally relative to the panel support arm 126
in directions perpendicular to the track beam 122, thereby allowing
for lateral adjustment of the detector panel 127 relative to the
imaging source 125. Lateral adjustments of either the imaging
source 125 or the detector panel 127 can facilitate methods in
accordance with embodiments of the invention for determining the
distance between the imaging source 125 and the defect 142, as
explained in greater detail below.
[0036] FIGS. 3 and 4 are front elevation views of the display
screen 132 of FIG. 1 showing images of the structure 140
corresponding to the imaging system of FIG. 2 in two different
positions. As best seen in FIG. 2, the structure 140 having the
defect 142 is positioned between the imaging source 125 and
detector panel 127 for inspection of the weld 141. When the imaging
system 120 is in a position so that the plane of the
circumferential weld 141 is parallel to the imaging beam axis 128,
and as shown in FIG. 3, it may be unclear to an operator whether
the defect 142 observed on the display screen 132 is on the part's
near side or far side. One way to answer this question using the
inspection system 100 is to rotate the imaging system 120 about the
axis 153 (FIG. 1) to a selected position, so that the plane of the
circumferential weld 141 is no longer parallel to the imaging beam
axis 128. As shown in FIG. 4, the circumferential weld 141 will be
depicted on the display screen 132 as an ellipse rather than a flat
line when the imaging system 120 is at position 291, and the
operator should then be able to determine on which side of the
structure 140 the defect 142 resides.
[0037] Without the ability to move the imaging system 120 in six
degrees of motion, many structures would require repositioning in
order to afford full inspection. This repositioning could prove an
expensive and time-consuming process, particularly for large or
awkward structures. One advantage of the inspection system 100 is
that it permits complete inspection of a structure without having
to stop the inspection process for structure repositioning.
[0038] General-purpose robots have benefited from many years of
research into the optimum human-machine programming interface. A
further advantage of the inspection system 100 is the ability to
program all of the required motions of the imaging system 120 into
the computer 130, thus eliminating the expense of a human operator.
In contrast, conventional x-ray machines with Cartesian control
systems often require manual control to carry out direct
inspections. Programming can also effectively reduce the cost of
inspecting large quantities of the same structural configuration,
since the same program can be used to inspect all of the
structures.
[0039] Although the inspection system 100 can be used in the
methods explained above in accordance with FIGS. 1-4 to determine
the general location of the defect 142 on the structure 140, it is
the specific location of the defect that should be marked on the
structure so that a subsequent repair can be properly focused.
Identifying and marking the specific location of the defect 142 on
the structure 140 is not always straightforward. The
computer-generated cross-hairs 134 can illustrate on the display
screen 132 the position of a defect 142 relative to the imaging
beam axis 128. An operator may then be able to see, on the display
screen 132 at least, the positional relationship between the defect
142 and the imaging beam axis 128. However, since the imaging beam
itself is transparent, the operator will not be able to see where
the imaging beam axis 128 actually intersects the structure 140. As
a result, the operator may not be able to accurately identify the
specific location of the defect 142 on the structure 140 to
repair.
[0040] FIG. 5 is an isometric view of the imaging system 120 having
a targeting system 300 that provides a visual indication on the
structure 140 of the specific location of the defect 142, in
accordance with an embodiment of the invention. The targeting
system 300 includes one line generator 302 mounted on a top surface
326 of the imaging source 125, so that a projected light plane 303
is collinear with and vertically intersects the imaging beam axis
128. The targeting system 300 also includes another, separate line
generator 304 mounted to a side 327 of the imaging source 125 so
that a projected light plane 305 is collinear with and horizontally
intersects the imaging beam axis 128. Accordingly, the intersection
of the vertical and horizontal line planes 303 and 305 correspond
to the imaging beam axis 128. In one aspect of this embodiment, the
line generators 302 and 304 can be Focusable Compact Laser Diode
Modules from Edmund Scientific, structure no. F53228.
Alternatively, Diffracted Line Generator Optic 60-degree fan angle
laser line generators can be used, also from Edmund Scientific
stock, structure no. F53759. In yet other embodiments, other
suitable light or visible indicia sources can be used.
[0041] The targeting system 300 of this embodiment provides
illuminated cross-hairs 307 on the structure's outer surface as a
visual indication of an intersection 306 of the imaging beam axis
128 with the defect 142 in the structure 140 under inspection. In
one aspect of this embodiment, the line generators 302 and 304 are
orthogonally mounted relative to each other. In other embodiments,
the line generators 302 and 304 can be non-orthogonally mounted
relative to each other yet still provide illuminated cross-hairs
307 as a visual indication of the imaging beam axis 128. When the
line generators 302 and 304 are non-orthogonally mounted, the
respective light planes 303 and 305 can still be positioned
collinear with, and intersecting, the imaging beam axis 128 while
at a non-orthogonal angle relative to each other. Thus, the light
planes 303 and 305 will still project illuminated cross-hairs 307
(albeit non-orthogonal crosshairs) with an intersection collinear
with the imaging beam axis 128.
[0042] Since the intersection 306 of the illuminated cross-hairs
307 are collinear with the imaging beam axis 128, the operator has
a way of visually identifying where the imaging beam axis 128
actually strikes the structure 140 under inspection. By first using
the computer-generated cross-hairs 134 on the display screen 132
(FIG. 1) to center the imaging beam axis 128 on the defect 142, the
operator can then accurately identify the location of the defect
142 on the structure 140 by marking the spot 306 where the
cross-hairs 307 are illuminated on the structure 140. Accordingly,
the target system 300 can be used to accurately locate the defect
142 on the structure 140 so that the defect can be further
inspected or effectively repaired.
[0043] The target system 300 discussed above in accordance with
FIG. 5 can provide the lateral position of the defect 142 relative
to the imaging beam axis 128. There may be times during the
inspection of the structure 140, however, when it will be necessary
not only to know the lateral position of the defect 142, but also
the axial position of the defect on the structure along the imaging
beam axis 128. For example, referring back to FIGS. 2 and 3, an
image of the structure 140 taken from position 290 could disclose
the lateral position of the defect 142, but would not disclose
whether the defect was on the structure's near side, far side, or
internal portion. And use of the targeting system 300 would not
answer this question. When encountering this situation, one
approach as explained above is to maneuver the imaging system 120
while the structure 140 remains stationary, thereby providing
another field of view. For example, by rotating the imaging system
120 to position 291 as illustrated in FIGS. 2 and 4. If the
operator can then determine the precise location of the defect 142
on the structure 140, the defect can be further inspected or
repaired.
[0044] While the axial and lateral positions of the defect 142 on
the structure 140 may be ascertained by maneuvering the imaging
system 120 as shown in FIG. 2 without having to reposition the
structure 140, it is also often desirable to accurately determine
the size of the defect. The imaging system 120 is configured to
determine the actual distance between the imaging source 125 and
the defect 142. Once this distance is known, it can be used to
determine the magnification of the defect's image as projected onto
the imaging panel 127, thereby allowing the size of the defect to
be accurately determined.
[0045] FIG. 6 is a schematic top view of the imaging system 120
configured for determining the size of the defect 142 by
determining a distance D.sub.sp between the imaging source 125 and
the defect using a method in accordance with an embodiment of the
invention. This method requires principally lateral movement of the
imaging source 125 relative to the defect 142, as explained above
with reference to FIG. 2. The distance D.sub.sp between the imaging
source 125 and the defect 142 can be determined using the computer
130 (FIG. 1) and Equation (1) below: 1 D sp = D sd r robot r image
+ r robot D sp = distance between the imaging source 125 and the
defect 142 D sd = distance between the imaging source 125 and the
detector panel 127 r robot = lateral movement of the imaging source
125 r image = lateral movement of the defect image ( 1 )
[0046] The positions of the imaging source 125 and the detector
panel 127 on the respective source and panel support arms 124 and
126 are known. Accordingly, the distance D.sub.sd between the
imaging source 125 and the detector panel 127 is determined via the
computer by determining the distance between the source support arm
124 and the panel support arm 126. Alternatively, the distance
D.sub.sd between the imaging source 125 and the detector panel 127
can be determined and provided to the computer 130 by conventional
optical measuring equipment. Once D.sub.sd is known, evaluation of
Equation (1) for D.sub.sp requires knowing a .DELTA.r.sub.robot,
the lateral distance moved by the imaging source 125 perpendicular
to the imaging beam axis 128 between positions 401 and 402; and a
.DELTA.r.sub.image, the lateral distance moved by the defect's
image across the stationary detector panel 127 between positions
412 and 414.
[0047] FIGS. 7 and 8 are front elevational views of the display
screen 132 illustrating the lateral movement of the defect's image
across the stationary detector panel 127 between positions 412 and
414 as needed to calculate .DELTA.r.sub.image, in accordance with
an embodiment of the invention. A sequence of events that can be
used to calculate .DELTA.r.sub.image, .DELTA.r.sub.robot, and
ultimately D.sub.sp is as follows: The operator first identifies
the defect 142 in the structure 140 being inspected. The defect 142
will be illustrated on the display screen 132 in the first defect
image position 412, as shown in FIGS. 6 and 7. The operator then
places a cursor on the display screen 132 on an identifiable point
415 of the defect 142, as shown in FIG. 7, and signals the computer
130 to record the first source position 401 of the imaging source
125 relative to the support system 121 (FIG. 1), and the first
defect image position 412 of the defect 142 relative to the
detector panel 127. The imaging source 125 is then moved laterally
relative to the structure 140 to a second source position 402. The
operator then places the cursor back on the same identifiable point
415 on the defect 142, as shown in FIG. 8, and signals the computer
130 to record the second source position 402 of the image source
125 relative to the first source position 401, and a second defect
image position 414 of the defect 142 relative to the first defect
image position 412. Given the four positional data points 401, 402,
412, and 414, the computer 130 determines .DELTA.r.sub.robot and
.DELTA.r.sub.image, and uses them with the known value of D.sub.sd
to evaluate Equation (1) to calculate D.sub.sp. In an alternate
embodiment, rather than have Equation (1) programmed into the
computer 130, D.sub.sd, .DELTA.r.sub.robot and .DELTA.r.sub.image
can be provided on the display screen 132 using suitable software,
and Equation (1) can be evaluated by the operator using other
computational means.
[0048] Once the distance D.sub.sp between the imaging source 125
and the defect 142 is known, a magnification of the defect, M, is
calculated using Equation (2) below: 2 M = Dsd Dsp D sp = distance
between the imaging source 125 and the defect 142 D sd = distance
between the imaging source 125 and detector panel 127 ( 2 )
[0049] Equation (2) shows that the magnification M is equal to the
distance D.sub.sd between the imaging source 125 and the detector
panel 127, divided by the distance D.sub.sp between the imaging
source and the defect 142. Once the magnification M of the defect
142 is known, the true size of the defect can be automatically
calculated by the computer 130 by dividing the size of the
magnified image as shown on the display screen 132 (FIGS. 7 or 8 )
by the magnification M.
[0050] FIG. 9 is a schematic top view of the imaging system 120
configured for determining the size of the defect 142 by
determining a distance D.sub.sp between the imaging source 125 and
the defect using a method in accordance with an alternate
embodiment of the invention. This method is similar to the method
described above in accordance with FIGS. 6-8 except that here the
detector panel 127 moves with the imaging source 125 laterally with
respect to the defect 142. As a result, this method can be useful
when the imaging source 125 and the detector panel 127 are both
fixed relative to their respective support arms 124 and 126 such
that lateral movement of the imaging source and the detector panel
relative to each other is precluded.
[0051] The distance D.sub.sp between the imaging source 125 and the
defect 142 can be determined in this alternate embodiment using
Equation (1) as shown above with D.sub.sd and .DELTA.r.sub.robot
determined as described above. Determining .DELTA.r.sub.image image
for use in this embodiment, however, requires taking into account a
lateral movement .DELTA.r.sub.detector of the detector panel 127
between a first detector panel position 421, corresponding to the
first source position 401, and a second detector panel position
422, corresponding to the second source position 402. As best seen
in FIG. 9, the defect image will be in a first defect image
position 412 when the detector panel 127 is in the first detector
panel position 421, and in a second defect image position 416 when
the detector panel is in the second panel position 422.
[0052] FIGS. 10 and 11 are front elevational views of the display
screen 132 illustrating the lateral movement of the defect's image
between positions 412 and 416 as needed to calculate
.DELTA.r.sub.image. A sequence of events that can be used to
calculate .DELTA.r.sub.image in this embodiment is as follows: The
operator first identifies the defect 142 in the structure 140 being
inspected. The defect 142 will be illustrated on the display screen
132 in the first defect image position 412, as shown in FIGS. 9 and
10. The operator then places a cursor on the display screen 132 on
the identifiable point 415 of the defect 142, as shown in FIG. 10,
and signals the computer 130 to record the first detector panel
position 421 relative to the support system 121 (FIG. 1), and the
first defect image position 412 of the defect 142 relative to the
detector panel 127. The imaging source 125 and detector panel 127
are then moved laterally relative to the structure 140 to the
second source and detector panel positions 402 and 422,
respectively. The operator then places the cursor back on the same
identifiable point 415 on the defect 142, as shown in FIG. 11, and
signals the computer 130 to record the second detector panel
position 422 relative to the first detector panel position 421, and
the second defect image position 416 of the defect 142 relative to
detector panel 127.
[0053] Given the two positional data points 421 and 422, the
computer 130 can determine the lateral distance
.DELTA.r.sub.detector moved by the detector panel 127. Given the
two positional data points 412 and 416, the computer 130 can also
determine a lateral distance .DELTA.r.sub.image+detector moved by
the defect image on the detector panel 127 between positions 412
and 416. The lateral distance .DELTA.r.sub.detector should then be
subtracted from the lateral distance .DELTA.r.sub.image+detector to
determine .DELTA.r.sub.image. Equation (1) above is then evaluated
using this value of .DELTA.r.sub.image along with D.sub.sd and
.DELTA.r.sub.robot to calculate D.sub.sp. Once the distance
D.sub.sp between the imaging source 125 and the defect 142 is
known, the magnification M of the defect is calculated using
Equation (2) above.
[0054] FIG. 12 is a schematic top view of the imaging system 120
configured for determining the size of the defect 142 and a
distance D.sub.sp.sub..sub.1 between the imaging source 125 and the
defect using alternate methods in accordance with another
embodiment of the invention. These methods involve axial movement
of the imaging source 125 relative to the detector panel 127 along
the track beam 122 as explained above with reference to FIG. 2. The
distance D.sub.sp.sub..sub.1 between the imaging source 125 and the
defect 142 can be determined using the computer 130 (FIG. 1) and
Equation (3) below: 3 Dsp 1 = s 2 s 1 Dsp 1 - s 2 / s 1 D sp 1 =
distance between the imaging source 125 and the defect 142 D sp =
axial movement of the imaging source 125 S 1 = first image size of
the defect 142 S 2 = second image size of the defect 142 ( 3 )
[0055] Evaluation of Equation (3) for D.sub.sp.sub..sub.1 requires
knowing an axial distance .DELTA.D.sub.sp the imaging source 125
moves between source positions 501 and 502, a first image size
S.sub.1 of the defect 142, and a second image size S.sub.2 of the
defect.
[0056] FIGS. 13 and 14 are front elevation views of the display
screen 132 illustrating first and second image sizes of the defect
142, respectively, in accordance with an embodiment of the
invention. Two identifiable points on the defect 142 should be
ascertainable to define the first defect image size S.sub.1 when
the imaging source 125 is in the first source position 501, and to
define the second defect image size S.sub.2 when the imaging source
125 is in the second source position 502. Two such distinct points
can be defined by points 531 and 532 when the imaging source 125 is
in the first source position 501, as shown in FIG. 13, and can be
defined by points 541 and 542 when the imaging source 125 is in the
second source position 502, as shown in FIG. 14.
[0057] A sequence of events that can be used to calculate S.sub.1,
S.sub.2, and ultimately D.sub.sp.sub..sub.1 is as follows: The
operator first identifies the defect 142 in the structure 140 being
inspected. The operator then sequentially places a cursor on the
display screen 132 on the two identifiable points 531 and 532 as
shown in FIG. 13, and signals the computer 130 to record the first
defect image size S.sub.1, and to record the first source position
501 of the imaging source 125 relative to the support system 121
(FIG. 1). The imaging source 125 is then moved axially to the
second source position 502, and the operator sequentially places
the cursor back on the two identifiable points, now 541 and 542 as
shown in FIG. 14, and signals the computer 130 to record the second
defect image size S.sub.2, and to record the second source position
502 of the imaging source 125 relative to the first source position
501. The imaging source 125 then returns to the first source
position 501. The computer 130 now has values for .DELTA.D.sub.sp,
S.sub.1, and S.sub.2, the variables required to evaluate Equation
(3) for the distance D.sub.sp.sub..sub.1 between the imaging source
125 at the first source position 501 and the defect 142.
[0058] The magnification M.sub.1 of the defect 142 is calculated
with Equation (4): 4 M 1 = Dsd ( 1 - s 2 s 1 ) ( s 2 s 1 ) Dsp D sp
= axial movement of the imaging source 125 D sd = distance between
the imaging source 125 and the detector panel 127 S 1 = first image
size of the defect 142 S 2 = second image size of the defect 142 (
4 )
[0059] Evaluation of Equation (4) only requires additionally
knowing the distance D.sub.sd between the imaging source 125 and
the detector panel 127. This value is either already known or
readily ascertainable by the computer 130 as discussed above.
[0060] By using the inspection system 100 disclosed herein, the
structure 140 can be comprehensively and automatically inspected in
real-time without requiring repositioning or refixturing of the
structure. In addition, the lateral position of the defect 142 can
be quickly identified on the surface of the structure 140 using the
targeting system 300. Similarly, the axial position of the defect
142 within the structure 140, as well as the size of the defect,
can also be accurately ascertained using the methods discussed
above in accordance with Equations (1)-(4), allowing the defect to
be further examined or repaired as needed. This provides for
faster, more efficient, and less labor-intensive inspection of
structures which can reduce the overall manufacturing costs.
Although specific embodiments, and examples for, the present
invention are described herein for illustrative purposes, it will
be apparent to those of skill in the art that various equivalent
modifications can be made without departing from the spirit and
scope of the invention.
[0061] The teachings provided herein of the automated real-time,
non-destructive inspection system 100 can be applied to other
imaging systems in addition to the exemplary x-ray apparatuses and
methods described above. In general, in the following claims, the
terms used should not be construed to limit the invention to the
specific embodiments disclosed in the specification and the claims,
but should be construed to include all non-destructive test
equipment and methods that operate in accordance with the claims to
provide the real-time inspection and location techniques in
accordance with the disclosure and claims. Accordingly, the
invention is not limited by the disclosure but instead its scope is
to be determined entirely by the following claims.
* * * * *