U.S. patent application number 16/459009 was filed with the patent office on 2019-11-07 for gravity-based weld travel speed sensing system and method.
The applicant listed for this patent is Illinois Tool Works Inc.. Invention is credited to Bruce Patrick Albrecht, William Todd Watson.
Application Number | 20190337076 16/459009 |
Document ID | / |
Family ID | 53269712 |
Filed Date | 2019-11-07 |
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United States Patent
Application |
20190337076 |
Kind Code |
A1 |
Albrecht; Bruce Patrick ; et
al. |
November 7, 2019 |
GRAVITY-BASED WELD TRAVEL SPEED SENSING SYSTEM AND METHOD
Abstract
A welding system includes an orientation sensing system
associated with a welding torch and is configured to sense a
welding torch orientation relative to a direction of gravity. The
welding system also includes a processing system communicatively
couple to the orientation sensing system and configured to
determine an angular position of the welding torch relative to a
pipe based at least in part on the sense welding torch
orientation.
Inventors: |
Albrecht; Bruce Patrick;
(Neenah, WI) ; Watson; William Todd; (Mount
Prospect, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Illinois Tool Works Inc. |
Glenview |
IL |
US |
|
|
Family ID: |
53269712 |
Appl. No.: |
16/459009 |
Filed: |
July 1, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14297380 |
Jun 5, 2014 |
10335883 |
|
|
16459009 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B23K 2101/10 20180801;
B23K 9/0026 20130101; B23K 9/0956 20130101; B23K 9/0286 20130101;
B23K 2101/06 20180801 |
International
Class: |
B23K 9/00 20060101
B23K009/00; B23K 9/095 20060101 B23K009/095; B23K 9/028 20060101
B23K009/028 |
Claims
1. A welding system, comprising: an orientation sensing system
associated with a welding torch and is configured to sense a
welding torch orientation relative to a direction of gravity; and a
processing system communicatively coupled to the orientation
sensing system and configured to determine an angular position of
the welding torch relative to a pipe based at least in part on the
sensed welding torch orientation and a radius of the pipe.
2. The welding system of claim 1, wherein the processing system is
configured to determine a travel distance traveled by the welding
torch from an initial position to the angular position.
3. The welding system of claim 2, wherein the processing system is
configured to determine a travel speed of the welding torch based
on the determined position.
4. The welding system of claim 1, wherein the orientation sensing
system comprises at least one accelerometer.
5. The welding system of claim 4, wherein the orientation sensing
system comprises at least one gyroscope configured to measure of
angular changes of the welding torch.
6. The welding system of claim 1, wherein the processing system is
configured to determine the travel distance based at least in part
on a travel profile for an operator or a job.
7. The welding system of claim 6, wherein the travel profile
comprises a learned profile input using a teaching mode or an input
travel profile.
8. The welding system of claim 6, wherein the travel profile
comprises compensation for gravitational effects on welding
material during the weld.
9. The welding system of claim 1, wherein the processing system
determines the angular position of the welding torch in relation to
an initial position using the following equation: d=r*.PHI., where
d is the travel distance, r is the radius, and .PHI. is an angle
between a torch axis at the initial location and the torch axis at
the angular position.
10. The welding system of claim 1, comprising a weld area sensor
located within a weld area, wherein the weld area sensor is
configured to also sense orientation of the welding torch, and the
processing system is configured to fuse sensed orientations from
the orientation sensing system and the weld area sensor.
11. The welding system of claim 1, wherein the processing system is
configured to receive an indication of the radius from a job
information database or manual input from a user.
12. A method comprising: sensing an initial orientation of a
welding torch at an initial location of a pipe using one or more
orientation sensors; sensing an angular orientation of the welding
torch at an angular location of the pipe using the one or more
orientation sensors; determining an angular change in orientation
between the initial orientation and the angular orientation; and
deriving a travel distance of the welding torch from the initial
location to the angular location based on the angular change.
13. The method of claim 12, wherein deriving a travel distance
comprises determining the travel distance using the following
equation: d=r*.PHI., where d is the travel distance, r is a radius
of the pipe, and .PHI. is an angle between a torch axis at the
initial location and the torch axis at the angular position.
14. The method of claim 12 comprising compensating for a pipe that
is not parallel to the ground using the following equation to
determine a minor diameter of an ellipse formed by a projection of
the weld joint onto a plane perpendicular the ground:
d.sub.minor=d.sub.major*cos(.theta.), where d.sub.minor is the
minor diameter of the ellipse, d.sub.major is twice a radius of the
pipe, and .theta. is an inclination angle of the pipe.
15. The method of claim 12 determining the inclination angle by
placing the welding torch on the pipe and determining an
inclination orientation of the welding torch using the one or more
orientation sensors.
16. The method of claim 11 comprising determining travel speed
based on the travel distance.
17. The method of claim 16, comprising indicating the travel speed
to an operator moving the welding torch by: providing visual
feedback via a display; providing audible feedback; or providing
haptic feedback.
18. A retro-fit kit configured to couple to a welding torch,
comprising: an accelerometer configured to determine an initial
orientation of the welding torch and a subsequent angular
orientation; and a processor configured to: determine an angular
change in orientation between the initial orientation and the
subsequent angular orientation; and derive a travel speed of the
welding torch based on a travel distance from the initial location
to the angular location determined using the angular change and a
radius of the pipe at a weld joint.
19. The retro-fit kit of claim 18, wherein at least the
accelerometer is configured to physically couple onto the welding
torch.
20. The retro-fit kit of claim 18, wherein the processor is
enclosed in a housing configured to physically couple onto to the
welding torch.
Description
RELATED APPLICATIONS/INCORPORATION BY REFERENCE
[0001] The present application claims the benefit of United Kingdom
Patent Application No. 14/297,380, filed on Jun. 5, 2014, entitled
"Data Generation System and Method," now granted U.S. Pat. No.
10,335,883. The above-identified application is hereby incorporated
herein by reference in its entirety.
BACKGROUND
[0002] The invention relates generally to welding systems, and,
more particularly, to sensing systems for monitoring a travel speed
of a welding torch during a welding operation.
[0003] Welding is a process that has become ubiquitous in various
industries for a variety of types of applications. For example,
welding is often performed in applications such as shipbuilding,
aircraft repair, construction, and so forth. While these welding
operations may be automated in certain contexts, there still exists
a need for manual welding operations. In some manual welding
operations, it may be desirable to monitor weld parameters, such as
the travel speed of the welding torch in three-dimensional space,
throughout the welding operation. While the travel speed of an
automated torch may be robotically controlled, the travel speed of
the welding torch in manual operations may depend on the operator's
welding technique, the weld pattern and position, the experience of
the welding operator, and so forth. Unfortunately, it may be
difficult to measure this weld motion during a welding operation
due to features of the welding environment, operator
considerations, and so forth.
BRIEF DESCRIPTION
[0004] In a first embodiment, a welding system includes an
orientation sensor associated with a welding torch and configured
to sense a welding torch orientation relative to a direction of
gravity. The welding system also includes a processing system
communicatively couple to the orientation sensor and configured to
determine an angular position of the welding torch relative to a
pipe based at least in part on the sense welding torch
orientation.
[0005] In another embodiment, a method includes sensing an initial
orientation of a welding torch at an initial location of a pipe
using one or more orientation sensors. The method also includes
sensing an angular orientation of the welding torch at an angular
location of the pipe using the one or more orientation sensors. The
method further includes determining an angular change in
orientation between the initial orientation and the angular
orientation. Furthermore, the method includes deriving a travel
distance of the welding torch from the initial location to the
angular location based on the angular change and a radius of the
pipe at a weld joint
[0006] In a further embodiment, a retro-fit kit configured to
couple to a welding torch includes an accelerometer configured to
determine an initial orientation of the welding torch and a
subsequent angular orientation. The retro-fit kit also includes a
processor configured to determine an angular change in orientation
between the initial orientation and the subsequent angular
orientation. The processor is also configured to cause the
processor to derive a travel speed of the welding torch based on a
travel distance from the initial location to the angular location
determined using the angular change and a radius of the pipe at a
weld joint.
DRAWINGS
[0007] These and other features, aspects, and advantages of the
present invention will become better understood when the following
detailed description is read with reference to the accompanying
drawings in which like characters represent like parts throughout
the drawings, wherein:
[0008] FIG. 1 is a block diagram of an embodiment of a welding
system utilizing a welding torch with travel speed determination as
disclosed;
[0009] FIG. 2 is a block diagram of an embodiment of the welding
system of FIG. 1, including a travel speed sensing system for
detecting a travel speed of the welding torch;
[0010] FIG. 3 is a perspective view of an embodiment of the welding
system of FIG. 2 used to determine travel speed of the welding
torch around a pipe;
[0011] FIG. 4 is a cross-sectional view of an embodiment of a weld
joint welded using the welding system of FIG. 2;
[0012] FIG. 5 is a view of an embodiment of a travel profile used
to determine travel speed of the welding torch of FIG. 2;
[0013] FIG. 6 is a perspective view of an embodiment of a pipe with
an inclination angle that may be welded using the welding system of
FIG. 2; and
[0014] FIG. 7 is a block diagram of an embodiment of a speed
sensing system that may be used to determine a weld travel speed or
travel distance of a welding torch.
DETAILED DESCRIPTION
[0015] As described in detail below, provided herein are systems
and methods for determining the travel speed of a welding device
during a welding operation. The foregoing systems and methods may
be used separately or in combination to obtain information during
the welding operation relating to the three dimensional speed of
the welding torch along the surface of the metal as the metal is
being welded. In some embodiments, these methods may be utilized
during unconstrained or manual welding operations to offer
advantages over traditional systems in which it may be difficult to
measure the weld motion. However, the foregoing systems and methods
may also be utilized in a variety of suitable welding systems, such
as automated or robotic systems.
[0016] Interpass temperatures are important in the micro-structural
properties of weldments, such as yield and tensile strength. One
method of estimating and/or limiting interpass temperatures may
include estimating travel speed. High interpass temperatures that
may result from slow travel speed cause a reduction in strength of
the welded connection and/or surrounding metal. Slow travel speed
also may result in overbeading welded connections and inefficient
welding by an operator. Travel speeds that are too fast may
indicate that the welding connection is incompletely formed.
Present embodiments are directed toward systems and methods for
sensing a travel speed of a welding torch using one or more
orientation sensors (e.g., accelerometer sensors and/or gyroscope
sensors). The orientation sensors may be disposed on, physically
coupled to, or in communication with the welding torch. The travel
speed sensing system is configured to detect a position and an
orientation of the welding torch relative to a workpiece. In some
embodiments, the orientation sensors may include gravity sensors
(e.g., accelerometers), sensors for measuring angular change (e.g.,
gyroscopes) or other sensors suitable for tracking an orientation
of the welding torch.
[0017] As discussed below, in some embodiments, the orientation
sensor(s) may be utilized to monitor an angular position of the
welding torch relative to a workpiece, such as a pipe workpiece.
Certain embodiments also include one or more other sensors
connected to or and/or located in the welding torch. The travel
speed sensing system is configured to determine or detect the
travel speed based on orientations determined from the orientation
sensors. Using an expected travel angle and location, an expected
orientation may be determined and used to compare to orientations
measured via orientation sensors (generally referred to herein as
"orientation sensors; e.g., accelerometers, gyroscopes). The travel
angle may vary according to a travel profile that may be manually
input, a standard travel angle, or a travel angle that is learned
through a teaching process prior to welding. Furthermore, in some
embodiments, the orientation sensors may be used to determine an
inclination angle of the workpiece to be welded, such as one or
more segments of pipe in order to translate gravity direction data
into orientation of the welding torch in relation to the
workpiece.
[0018] Turning now to the figures, FIG. 1 is a block diagram of an
embodiment of a welding system 10 in accordance with the present
techniques. The welding system 10 is designed to produce a welding
arc 12 with a workpiece 14 (e.g., pipe). The welding arc 12 may be
generated by any type of welding system or process, and may be
oriented in any desired manner. For example, such welding systems
may include gas metal arc welding (GMAW) systems, and may utilize
various programmed waveforms and settings. The welding system 10
includes a power supply 16 that will typically be coupled to a
power source 18, such as a power grid. Other power sources may, of
course, be utilized including generators, engine-driven power
packs, and so forth. In the illustrated embodiment, a wire feeder
20 is coupled to a gas source 22 and the power source 18, and
supplies welding wire 24 to a welding torch 26. The welding torch
26 is configured to generate the welding arc 12 between the welding
torch 26 and the workpiece 14. The welding wire 24 is fed through
the welding torch 26 to the welding arc 12, melted by the welding
arc 12, and deposited on the workpiece 14.
[0019] The wire feeder 20 will typically include control circuitry,
illustrated generally by reference numeral 28, which regulates the
feed of the welding wire 24 from a spool, and commands the output
of the power supply 16, among other things. Similarly, the power
supply 16 may include control circuitry 30 for controlling certain
welding parameters and arc-starting parameters. The spool will
contain a length of welding wire 24 that is consumed during the
welding operation. The welding wire 24 is advanced by a wire drive
assembly 32, typically through the use of an electric motor under
control of the control circuitry 28. In addition, the workpiece 14
is coupled to the power supply 16 by a clamp 34 connected to a work
cable 36 to complete an electrical circuit when the welding arc 12
is established between the welding torch 26 and the workpiece
14.
[0020] Placement of the welding torch 26 at a location proximate to
the workpiece 14 allows electrical current, which is provided by
the power supply 16 and routed to the welding torch 26, to arc from
the welding torch to the workpiece 14. As described above, this
arcing completes an electrical circuit that includes the power
supply 16, the welding torch 26, the workpiece 14, and the work
cable 36. Particularly, in operation, electrical current passes
from the power supply 16, to the welding torch 26, to the workpiece
14, which is typically connected back to the power supply 16 via
the work cable 36. The arc generates a relatively large amount of
heat that causes part of the workpiece 14 and the filler metal of
the welding wire 24 to transition to a molten state that fuses the
materials, forming the weld.
[0021] To shield the weld area from being oxidized or contaminated
during welding, to enhance arc performance, and to improve the
resulting weld, the welding system 10 may also feed an inert
shielding gas to the welding torch 26 from the gas source 22. It is
worth noting, however, that a variety of shielding materials for
protecting the weld location may be employed in addition to, or in
place of, the inert shielding gas, including active gases and
particulate solids. Moreover, in other welding processes, such
gases may not be used, while the techniques disclosed herein are
equally applicable.
[0022] Presently disclosed embodiments are directed to an
angular-based travel speed sensing system used to detect a change
in position of the welding torch 26 over time throughout the
welding process. In some embodiments, the travel speed of the
welding torch 26 may refer to a change in three dimensional
position with respect to time measured using at least an
accelerometer 38 and/or gyroscope sensor 40 located in, on, or
associated with the welding torch 26. In certain embodiments, the
accelerometer 38 may include a single triaxial accelerometer
capable of measuring dynamic motion, such as weld weaving. In other
embodiments, the travel speed of the welding torch 26 may refer to
a change in two-dimensional of the welding torch 26 determined
using two orientation sensors (e.g., accelerometers). For example,
the two-dimensional position may be calculated with respect to a
plane parallel to a direction of gravity. As mentioned above,
although FIG. 1 illustrates a GMAW system, the presently disclosed
techniques may be similarly applied across other types of welding
systems, including gas tungsten arc welding (GTAW) systems and
shielded metal arc welding (SMAW) systems, among others.
Accordingly, embodiments of the welding travel speed sensing system
may be utilized with welding systems that include the wire feeder
20 and gas source 22 or with systems that do not include a wire
feeder and/or a gas source, depending on implementation-specific
considerations.
[0023] FIG. 2 is a block diagram of an embodiment of the welding
system 10, including a travel speed sensing system 50 in accordance
with presently disclosed techniques. The travel speed sensing
system 50 may include, among other things, a travel speed
monitoring device 52 configured to process signals received from
one or more sensors 54 (e.g., accelerometers, gyroscopes, etc.)
incorporated within or connected to the welding torch 26 (e.g., via
an add-on kit). As discussed in detail below, the sensors 54 may be
utilized to determine a position of the welding torch 26 around the
workpiece 14. In some embodiments, the welding torch 26 and/or a
welding torch add-on kit may include one or more processor(s) 55
that may analyze and transform measurements from the sensors 54 and
be physically coupled onto the welding torch 26 (e.g., via a
housing). In some embodiments, the sensor 54 and/or processor 55
may include shielding for one or more components.
[0024] The welding system 10 may also include one or more sensors
56 located within a weld area 58 external to the welding torch 26
and capable of capturing various details about a welding technique
used to weld the workpiece 14. The sensors 56 may be any desirable
type of sensor that produces a signal indicative of a position of
the welding torch 26, an orientation of the welding torch 26,
and/or temperature of various portions of the workpiece 14 within a
weld area 58. The weld area 58 may include any three-dimensional
space within which a welding operation is performed via the welding
system 10. For example, the sensors 56 may include an array of
microphones configured to detect a position of a welding arc 12, a
sound emitter disposed on the welding torch 26, or any other sound
indicative of a position of the welding torch 26 operating in the
weld area 58. In other embodiments, the sensors 56 may include one
or more optical sensors configured to sense a light emitted from
the welding torch 26 (e.g., welding arc 12). In some embodiments,
one or more of the sensors 56 may be located on a welding helmet to
aid in determining a position of the welding torch 26.
[0025] The one or more sensors 54, 56 and/or the processor(s) 55
may send signals 60 indicative of welding torch position to the
travel speed monitoring device 52. Using the signals 60, the travel
speed monitoring device 52 may then determine a position of the
welding torch 26 based at least in part on the signals 60 sent from
the sensors (e.g., the accelerometer(s) 38 and/or gyroscope(s) 40).
That is, the travel speed sensing system 50 may receive the signals
60, and determine the travel speed of the welding torch 26 based on
these signals 60. In some embodiments, the workpiece 14 may be
placed in any spatial relationship to the sensors 56, and a
calibration scheme may be applied via the weld travel speed system
50. For example, the welding torch 26 may be placed at one or more
known positions relative to the workpiece 14, and sensor
measurements taken at these positions may be used to calibrate the
spatial relationship between the workpiece 14 and the sensors
56.
[0026] As shown, the travel speed monitoring device 52 may include
a processor 62, which receives inputs such as sensor data from the
sensors 54, sensors 56 and/or the processor(s) 55 via the signals
60. Each signal may be communicated over a communication cable, or
wireless communication system (e.g., ZigBee), from the one or more
sensors 54, 56. In an embodiment, the processor 62 may also send
control commands to a control device 64 of the welding system 10 in
order to implement appropriate actions within the welding system
10. For example, the control device 64 may control a welding
parameter (e.g., power output, wire feed speed, gas flow, etc.)
based on the determined travel speed of the welding torch 26. The
processor 62 also may be coupled with a feedback device 66 that
provides an indicator of travel speed of the welding torch 26 based
on input from the sensors 54, 56. In some embodiments, the feedback
device 66 includes a memory 68 and processor(s) 70 separate from
the processor of the travel speed monitoring device 52. However, in
certain embodiments, the feedback device 66 may rely upon the
processor 62 of the travel speed monitoring device 52. In some
embodiments, the feedback device 66 includes a human machine
interface (HMI) 72. In some embodiments, the HMI 72 includes a
display of that may provide a visual indicator of the travel speed
of the welding torch 26 based on the travel speed determined by the
travel speed monitoring device 52. In certain embodiments, display
of the HMI 72 may be located in a welding helmet used during
welding in the weld area 58. In some embodiments, the display may
be separate from the welding helmet, such as a mounted display
visible from within the weld area. Furthermore, the HMI 72 may
include haptic feedback to the user via gloves, helmet, or the
welding torch 26. The HMI 72 may be used to provide visual, haptic,
and/or audible indicators of the travel speed of the welding torch
26 directly to the welding operator as the operator is performing
the weld and/or indications that the operator's travel speed is too
slow, too fast, or in an appropriate range for a particular weld.
The processor 62 may receive additional sensor feedback 84 from the
welding system 10, in order to monitor other welding parameters.
These other welding parameters may include, for example, a heat
input to the workpiece 14.
[0027] As illustrated, the processor 62 is coupled to a memory 74,
which may include one or more software modules 76 that contain
executable instructions, transient data, input/output correlation
data, and so forth. The memory 74 may include non-transitory,
computer-readable medium, such as volatile or non-volatile memory.
Furthermore, the memory 74 may include a variety of machine
readable and executable instructions (e.g., computer code)
configured to provide a calculation of weld travel speed, given
input sensor data. Generally, the processor 62 receives such sensor
data from the one or more sensors 54, 56 and/or the processor(s)
55, and references data stored in the memory 74 to implement such
calculations. In this way, the processor 62 is configured to
determine a travel speed of the welding torch 26, based at least in
part on the signals 60.
[0028] In some embodiments, the travel speed sensing system 50 may
be provided as an integral part of the welding system 10 of FIG. 1.
That is, the travel speed sensing system 50 may be integrated into
a component of the welding system 10, for example, during
manufacturing of the welding system 10. For example, the power
supply 16 may include appropriate computer code programmed into its
software to support the travel speed sensing system 50. However, in
other embodiments, the travel speed sensing system 50 may be
provided as a retrofit kit that may enable existing welding systems
10 with the travel speed sensing capabilities described herein. The
retrofit kit may include, for example, the travel speed sensing
system 50, having the processor 62 and the memory 74, as well as
one or more sensors 54 which may be attached to the welding torch
26 from which the travel speed sensing system 50 receives sensor
input. In some embodiments, the retrofit kit may also include a
welding torch 26 having the sensors 54 installed. To that end, such
retrofit kits may be configured as add-ons that may be installed
onto existing welding systems 10, providing travel speed sensing
capabilities. Further, as the retrofit kits may be installed on
existing welding systems 10, they may also be configured to be
removable once installed.
[0029] FIG. 3 illustrates an embodiment of the welding system 10
that may use the travel speed sensing system 50. The travel speed
sensing system 50 may determine the weld travel speed of the
welding torch 26 while an operator 80 forming a weld 82 on the
workpiece 14 (e.g., pipe). In the illustrated embodiment, the
sensors 54 are located on and/or in gloves 84 of the operator 80 in
addition or alternative to placement in the welding torch 26. As
illustrated, the weld 82 may be formed on a cylindrical-shaped
workpiece 14 with the welding torch 26 substantially perpendicular
or at a generally known angle to the workpiece 14 during formation
of the welded connection on the workpiece 14 that has a known
diameter. Using the known diameter an orientation based on a travel
profile between the workpiece 14 and the welding torch 26, a travel
speed may be determined over time based on an orientation of the
welding torch 26 using torch geometry, such as the cross-sectional
view of an embodiment of the welding system 10 illustrated in FIG.
4. During operation, the welding torch 26 experiences a downward
force 90 associated with gravity. The direction of the downward
force 90 may be detected by the sensors 54 (e.g., accelerometer 38)
for use in determining a travel speed of the welding torch 26. For
example, when the welding torch 26 is placed at an initial location
92 at a substantially perpendicular or other angle with the
workpiece 14, a torch axis 94 passes substantially through a center
point 96 of the workpiece 14 for the cross-section (e.g.,
two-dimensional slice) of the workpiece 14. As the welding torch 26
travels a travel distance 98 to a second location 100 around an
outer diameter of the workpiece 14 while maintaining a desired
orientation with respect to the workpiece 14, the torch axis 94
continues to pass through the center point 96. In other words, the
torch axis 94 may extend through a radius 102 (or known or assumed
orientation) at the initial location 92 and through a radius 104
(or other known or assumed orientation at the second location 100.
The distance 98 may be determined as a function of an angle .PHI.
between the radii 102 and 104 and the length of the radii 102 and
104 according to the following function:
d=r*.PHI. (Equation 1),
where d is a length of the travel distance 98, r is a length of the
radii 102 and 104, and .PHI. is the angle between the radii 102 and
104 measured in radians. In some embodiments, the length of the
radii 102 and 104 may be known (e.g., in a job information
database) and/or input into the welding system 10 by an operator.
Furthermore, the travel speed may be determined by dividing the
travel distance 98 by the time interval of travel that the travel
speed monitoring system 50 determines that the welding torch 26
traveled between the initial location 92 and the second location
100.
[0030] To determine a measure of the angle 4), the sensors 54 may
measure a change in a direction of gravity in relation to the torch
axis 94 direction during travel from the initial location 92 to the
second location 100. In other words, the angle .PHI. may be
determined as the angle between an initial orientation of the torch
axis 94 at the initial location 92 and a second orientation of the
torch axis 94 at the second location 100. Although perpendicular
orientation may be used at some locations around the workpiece 14,
in some locations, such as locations 106 and 108, alternative
orientations may be used or desirable. For example, at locations
106 and 108, a MIG torch may have a slight torch angle from torch
orientations 110 to push a puddle of welding material up to
compensate for the downward force 90 on the welding material. In
such embodiments, a travel profile may be used to compensate for
the difference between the torch orientations 110 and perpendicular
orientations 112 to provide a desired travel pace at certain points
around the workpiece 14.
[0031] FIG. 5 illustrates an embodiment of a travel profile 110
that reflects expected travel around a pipe (e.g., workpiece 14). A
travel angle 112 may be chosen as perpendicular or with variations
to account for various factors (e.g., gravity effect on weld
material at vertically oriented weld locations). In some
embodiments, the travel angle 112 may be a standard torch angle
deflection. In certain embodiments, the travel angle 112 may be
manually entered or may be determined from a teaching operation
performed prior to welding. For example, the travel angle 112 may
be determined using the sensors 56 or the training methods
disclosed in U.S. Patent Publication No. 2013/0206741 filed on Jan.
31, 2013, which is herein incorporated by reference in entirety.
Furthermore, the travel angle 112 may be tailored for a specific
operator through the training operation to more accurately
determine a position around the pipe (e.g., workpiece 14) based on
the operator's personal technique at various locations around the
pipe.
[0032] In the illustrated embodiment, the travel angle 112 starts
at an angular position of 0.degree. (e.g., 12 o'clock position)
with an angle of 0.degree. off perpendicular. However, as the
welding torch 26 approaches an angular position of 90.degree.
(e.g., 3 o'clock position), the angle may increase to a degree of
deflection (e.g., 15.degree.) configured to push welding material
in an upward direction to counteract gravity. The angle may return
towards 0.degree. off of perpendicular near the angular position of
180.degree. (e.g., 6 o'clock position), but the welding torch 26
may deflect downwards (e.g., -15.degree.) nearer to the angular
position of 270.degree. (e.g., 9 o'clock position) to again
compensate for the force of gravity on the welding material. Using
the travel angle 112, an expected orientation angle 114 with
respect to the original torch axis 94. The expected orientation
angle 114 may reflect changes in the travel angle 112 that reflects
a variation (e.g., due to operator techniques) from a constant
perpendicular orientation angle 116 around the pipe. As
illustrated, variations in the selected travel angle 112 correspond
to similar variations in the orientation angle.
[0033] As illustrated, for piping and similar workpieces, the
travel path 112 and expected orientation angle 114 may be a
continuous sinusoidally-shaped line. However, an actual orientation
angle may be discrete based on a number of sampled locations and
orientations over time. However, in some embodiments, the samplings
may be exposed to a low-pass filtering, time-based running average
filtering, or predictive Kalman filters to filter out unwanted
information other than the relatively slowly changing orientation
angle. The filtering may be performed using hardware or software
filters. Furthermore, average torch orientation may be calculated
at longer intervals (e.g., several seconds) to focus on the changes
to the relatively slowly changing orientation angle.
[0034] Moreover, the actual orientation angle may be further
refined by fusing information from one or more other sensors, such
as the sensors 56 and/or the gyroscope 40. For example, by using
the gyroscope 40, such as a triaxial gyroscope sensor, the rotation
rate of the torch about 3 orthogonal axes may integrated in time to
obtain an estimate of the current angle that can be combined with
accelerometer signals to improve the accuracy of the determined
angle of orientation by correcting for sensor errors, drift, and
dynamic accelerations.
[0035] The foregoing discussion discusses pipes that are
substantially parallel to the ground. However, a further analysis
may be used to determine orientation angles for pipes that are not
parallel to the ground. For example, in the welding system 120 of
FIG. 6. A center vector 122 of the pipe 124 forms an angle .theta.
with the ground 126, where 0.degree.<.theta.<90.degree..
Although in the illustrated embodiment, the pipe 124 contacts the
ground 126, certain embodiments of the welding system 120, the pipe
124 may not contact the ground 126. Instead, the angle .theta.
indicates an extension of the center vector 122 and/or an edge of
the pipe 124. A plane formed by the weld joint 128 of the pipe 124
may be perpendicular to the center vector 122 as a circle. However,
when the weld joint 128 is projected onto a plane defined by the
direction of the force of gravity 130, a projected weld joint 132
on the plane may form an ellipse. Since the projected weld joint
132 is an ellipse, the projected weld joint 132 has a major
diameter 134 and a minor diameter 136. The major diameter 134 is
the same length as a diameter 138 of the pipe 124. However, the
minor diameter 136 varies based on the value of angle .theta. and
may be determined using the following equation:
d.sub.minor=d.sub.major*cos(.theta.) (Equation 2),
where d.sub.minor is the length of the minor diameter 136 and
d.sub.major is the length of the major diameter 134. Using
d.sub.minor and d.sub.major, a distance traveled on the pipe around
the ellipse may be determined or approximated. For example, in some
embodiments, the distance traveled on the perimeter of the ellipse
may be approximated using the following equation:
distance = .phi. * d major 2 + d minor 2 8 . ( Equation 3 )
##EQU00001##
In certain embodiments, the distance traveled on the perimeter of
the ellipse may be approximated using the following equation:
distance = .phi. 8 [ 6 ( d major + d minor ) - 3 d major + 10 d
major * d minor + 3 d minor ] . ( Equation 4 ) ##EQU00002##
In some embodiments, other suitable elliptical perimeter
approximation formulas may be used by multiplying the perimeter by
.PHI./2.pi..
[0036] In some embodiments, the measure of angle .theta. may be
known and/or input by an operator for the welding system 120. In
certain embodiments, the angle .theta. may be determined using the
welding system 120, such as welding torch 26. For example, the
welding torch 26 may be laid on the pipe 124 so that the
orientation sensors 54 of the welding torch 26 may be used to
determine the angle .theta. prior to welding the pipe 124.
[0037] Using the projected weld joint 132 model, the travel speed
for the welding torch 26 around a pipe 124 may be determined even
when the pipe is not parallel to the ground 126 (that is, generally
perpendicular to the force of gravity). Although the previous
discussion pertains to welding around a whole circumference of a
pipe, the foregoing techniques may be applied to arc-shaped
segments encompassing part of the circumference around a pipe. In
fact, a circular pipe may be subdivided into two or more sub-arcs
that may have separate expectations as the total pipe joint is
welded. For example, the travel path 112 may be sub-divided into
four distinct sub-segments that may be welded at one time or at
different times.
[0038] FIG. 7 illustrates an embodiment of a process 140 for
determining a travel speed of a welding torch 26 during welding of
a pipe 124. The process 140 may be implemented using the processors
55, 62, and/or 70. In some embodiments, the processors 55, 62,
and/or 70 implement instructions stored in the memory 74 and/or 68.
In certain embodiments, the processors 55, 62, and/or 70 may
perform the process 140 as hardware, software, or some combination
thereof. The process 140 includes determining a current welding
torch orientation in relation to a gravity vector using one or more
orientation sensors 54 (block 142). In some embodiments, the
orientation sensors 54 may include one or more accelerometers 38
and/or one or more gyroscopes 40. In some embodiments, the
measurements from the orientation sensors 54 may be fused with
additional measurements from other sensors (e.g., sensors 56).
Using the determined orientation, determine a change from an
initial welding torch orientation to the current welding
orientation (block 144). In some embodiments, the change includes
an angular change in one or more orthogonal axes (e.g., using a
triaxial accelerometer) that is indicative of movement of the
welding torch 26 during operation.
[0039] Using the determined change and a radius of the pipe 124,
the process 140 includes calculating a distance of travel based on
the angle and the radius (block 146). In certain embodiments, the
radius of the pipe 124 may be input and/or known before welding. In
some embodiments, the radius of the pipe 124 may be determined by
scanning a bar code, QR code, RFID (radio field identification), or
other suitable data conveying devices that may be located on or
near the pipe. In certain embodiments, scans are used to identify a
job information database that stores information about the pipe
124, such as its radius. In certain embodiments, calculating the
distance of travel includes calculating the distance of travel
based on a travel angle profile. In some embodiments, the travel
angle profile may correspond to a standard travel profile for a
particular weld connection and geometry. In certain embodiments,
the travel angle profile may be learned by the welding system 10
using a teaching operation that reflects techniques specific to an
operator or configured to compensate for various factors (e.g.,
gravity effect on welding material). The process 140 further
includes determining a speed of travel based on a time over which
the welding torch traverses the distance of travel (block 148). In
some embodiments, the speed of travel may be averaged across
multiple determinations of distance and/or determined over periods
of computation, such as 1, 2, 3, 4, or more seconds.
[0040] The determined travel speed may provide documentation for
weld quality based at least in part on linear input and power
input. The travel speed may also be used to provide real-time
feedback to an operator via the feedback device 66 reflecting the
weld progression. Additionally, it should be noted that in certain
embodiments, it may be desirable to determine and monitor the
travel speed of the welding torch 26 over the total distance of the
workpiece 14 being welded, and not the total distance traveled by
the welding torch 26. That is, in instances in which the operator
110 performs a weld in a traditional pattern, such as weaving, the
welding torch 26 may travel a large distance while only covering a
small portion of the workpiece 14. If such a technique is used by
the operator 110, the interpretation of the weld travel speed may
be adjusted to compensate for the weaving motion to derive the
travel speed along a travel direction (X) of the weld. Therefore,
in some embodiments, the weld travel speed will not simply be the
sum of the length of the weld vector. Instead, the algorithm for
calculating weld travel speed may continually determine the
straight line or planar distance between a current weld location
and some prior reference location and divide this distance by the
elapsed weld time between the two locations. The elapsed time
between points may be held constant, or the initial reference point
may be held constant at a weld initiation location. In some
embodiments, the elapsed time between the two locations may be
adjusted to be a longer time interval when weaving is detected.
[0041] In some embodiments, the distance between the current weld
tip location and the prior reference location may be calculated,
for example, by the Pythagorean Theorem if the displacements in the
travel direction (X) and weave direction (Y) (or any two orthogonal
directions on the weld surface) is known. If this distance is found
to be non-monotonically increasing, then a weaving technique may be
identified. Further, in embodiments in which a particular pattern
(e.g., zigzag pattern) is being performed by the operator 110, the
pattern may be identified by evaluating the excursions in the weave
direction (Y) or the near lack of travel in the travel direction
(X) for some periods of time. The amount of weaving might also be
detected by sensing the excursions in the weave direction (Y). For
example, in an embodiment, the time between the current weld
location and the prior reference location may be adjusted according
to the amount of weaving detected (e.g., more weaving corresponds
to a longer time). Additionally, any low-pass filtering or time
averaging of the calculated travel speed may be adjusted (e.g.,
more weaving corresponds to a longer time or lower frequency
filter).
[0042] While only certain features of the invention have been
illustrated and described herein, many modifications and changes
will occur to those skilled in the art. It is, therefore, to be
understood that the appended claims are intended to cover all such
modifications and changes as fall within the true spirit of the
invention.
* * * * *