US 12,005,531 B1 · Method of automatically welding welded seam of saddle line for saddle-type T joint

Abstract

A method of automatically welding a welded seam of a saddle line for a saddle-type T joint belonging to the technical field of welding is provided, including: establishing a groove cross-sectional model, solving a variation law of a groove cross-sectional area, and planning a welding bead and a welding process parameter according to the groove cross-sectional area; establishing a welding torch pose mathematical model and obtaining a pose homogeneous transformation matrix T of a welding torch; establishing a three-dimensional model of a main pipe and a branch pipe, building a welding system through offline software, importing welding spot pose information, and generating welding torch pose offline command through the offline software; and performing automatic welding of the welded seam of the saddle line for the saddle-type T joint according to the planned welding bead and the welding process parameter and the generated welding torch pose offline command.

A method of automatically welding a welded seam of a saddle line for a saddle-type T joint, comprising:

S1:
establishing a groove cross-sectional model, solving a variation law of a groove cross-sectional area, and planning a welding bead and a welding process parameter according to the groove cross-sectional area, wherein the groove cross-sectional area specifically is:
S
=
δ
2
⁢
tan
⁢
β
+
δ
⁡
(
n
·
1
-
(
r
m
)
2
-
n
·
1
-
(
r
+
δ
m
)
2
)
2
-
(
∫
r
r
+
δ
n
·
1
-
(
x
1
m
)
2
⁢
dx
1
-
∫
r
r
+
δ
(
n
·
1
-
(
r
+
δ
m
)
2
-
n
·
1
-
(
r
m
)
2
δ
⁢
(
x
1
-
r
)
+
n
·
1
-
(
r
m
)
2
)
⁢
dx
1
)
in the equations, δ is a wall thickness, β is an angle between a horizontal direction of a cross section where a welding spot is located and a groove, n is a semi-minor axis of an ellipse, r is a radius of an inner hole of a branch pipe, m is a semi-major axis of the ellipse, and x1 is an abscissa of
P
1
=
(
x
1
,
n
⁢
1
-
(
x
1
m
)
2
)
at any position on a groove cross section;
determining whether
S
max
-
S
mix
S
mix
is greater than a threshold when the welding process parameter is planned, using a changed welding process parameter if yes is determined, using the same welding process parameter if no is determined, and then determining the welding process parameter, wherein Smax is a maximum groove cross-sectional area, Smix is a minimum groove cross-sectional area, the threshold is 0.1 to 0.15, the welding process parameter includes:
a protective gas is pure argon, a gas flow rate is 25 L/min to 30 L/min, a dry extension of a welding wire is 12 mm to 15 mm, process parameters of backing welding are:
a wire feeding speed 8 m/min to 8.5 m/min, a welding speed 40 cm/min to 45 cm/min, a current 180 A to 195 A, a voltage 15.2 V to 16.3 V, and no swing;
process parameters of filling welding are:
a wire feeding speed 8 m/min to 9 m/min, a welding speed 30 cm/min to 40 cm/min, a current 180 A to 195 A, a voltage 15.2 V to 16.3 V, a swing amplitude 1 mm to 2 mm, and a frequency 3 HZ to 5 HZ;
and process parameters of covering welding are:
a wire feeding speed 9 m/min to 10 m/min, a welding speed 30 cm/min to 40 cm/min, a current 195 A to 236 A, a voltage 16.3 V to 17.6 V, a swing amplitude 1.5 mm to 2.5 mm, and a frequency 3 HZ to 5 HZ;
S2:
establishing a welding torch pose mathematical model, wherein a pose homogeneous transformation matrix T of a welding torch is:
T
=
[
n
1
o
1
a
1
x
m
n
2
o
2
a
2
y
m
n
3
o
3
a
3
z
m
0
0
0
1
]
,
in the equation, ni, where i=1, 2, and 3, is a vector element of a tangent vector {right arrow over (u)} of any point on the saddle line, oi, where i=1, 2, and 3, is a vector element of a Y-axis direction vector {right arrow over (v)} of the welding torch, ai, where i=1, 2, and 3, is a vector element of a Z-axis direction vector {right arrow over (w)} of the welding torch, and xm, ym, and zm are translation distances of the welding spot relative to an origin of a robot, wherein a direction vector of a groove straight line is {right arrow over (l1)}, a tangent vector on a cross section of a main pipe where the welding spot is located is {right arrow over (l2)}, a pose of the welding torch is located at
φ
2
,
φ is an angle between the groove straight line at any cross section and a tangent line at the welding spot on the main pipe, the Z-axis direction vector of the welding torch is
l
→
1
❘
"\[LeftBracketingBar]"
l
→
1
❘
"\[RightBracketingBar]"
+
l
→
2
❘
"\[LeftBracketingBar]"
l
→
2
❘
"\[RightBracketingBar]"
,
an X-axis direction vector of the welding torch is a tangent direction of any point on the saddle line formed by intersection of the main pipe and the branch pipe, and the Y-axis direction vector of the welding torch is determined according to the right-hand rule of the Z-axis direction vector of the welding torch and the X-axis direction vector of the welding torch;
S3:
establishing a three-dimensional model of the main pipe and the branch pipe, building a welding system through an offline software, and importing a welding spot pose information in a form of (xm, ym, zm, w, p, r), wherein w, p, and r are angles of rotation around an X-axis, a Y-axis, and a Z-axis respectively and are obtained from the pose homogeneous transformation matrix T of the welding torch, and a welding torch pose offline command is generated through the offline software;
and
S4:
performing automatic welding of the welded seam of the saddle line for the saddle-type T joint according to the welding bead and the welding process parameter planned in step S1 and the welding torch pose offline command generated in step S3.

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Method of automatically welding welded seam of saddle line for saddle-type T joint

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Method of automatically welding welded seam of saddle line for saddle-type T joint

Life of this patent

Abstract

Claims5