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Research on off-line programming method of spatial intersection curve welding based on VTK

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Abstract and Figures

Robot off-line programming is widely used in the field of spatial intersection curve welding. However, several existing problems are needed to be resolved which include the following: the operation process depends on the third-party CAD software, the welding trajectory planning depends on the precise analytical formula, and the determination of welding posture lacks fusion of geometrical features of surrounding surfaces. This paper presents an off-line programming method of spatial intersection curve welding based on visualization toolkit (VTK). In this method, the visualization pipeline and observer/command mode of VTK are used to display the 3D model of the robot welding system and pick up the surfaces around the welding seam respectively. By calculating the normal vectors of the picked surfaces, the equidistant cutter planes perpendicular to these surfaces can be automatically created to form the planning weld nodes on the intersection of the surfaces, and the position and posture of the welding torch on weld nodes can be extracted. Furthermore, the position and posture along the weld curve are discretized by B-spline curve interpolation and quaternion spherical linear interpolation, respectively. Finally, the motion simulation is realized by the application of robot inverse kinematics. This method does not depend on the specific form of intersection, and all calculation processes are completed within the system, avoiding tedious external data calculation and import process. The correctness and practicability of the method are verified by the welding experiment of saddle-shaped cylindrical intersection pipes.
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ORIGINAL ARTICLE
Research on off-line programming method of spatial intersection
curve welding based on VTK
Lei Hong
1,2
&Baosheng Wang
2
&Zhenqin Xu
2
&Zhuwen Yan
2
Received: 14 April 2019 /Accepted: 4 November 2019
#Springer-Verlag London Ltd., part of Springer Nature 2019
Abstract
Robot off-line programming is widely used in the field of spatial intersection curve welding. However, several existing problems
are needed to be resolved which include the following: the operation process depends on the third-party CAD software, the
welding trajectory planning depends on the precise analytical formula, and the determination of welding posture lacks fusion of
geometrical features of surrounding surfaces. This paper presents an off-line programming method of spatial intersection curve
welding based on visualization toolkit (VTK). In this method, the visualization pipeline and observer/command mode of VTK
are used to display the 3D model of the robot welding system and pick up the surfaces around the welding seam respectively. By
calculating the normal vectors of the picked surfaces, the equidistant cutter planes perpendicular to these surfaces can be
automatically created to form the planning weld nodes on the intersection of the surfaces, and the position and posture of the
welding torch on weld nodes can be extracted. Furthermore, the position and posture along the weld curve are discretized by B-
spline curve interpolation and quaternion spherical linear interpolation, respectively. Finally, the motion simulation is realized by
the application of robot inverse kinematics. This method does not depend on the specific form of intersection, and all calculation
processes are completed within the system, avoiding tedious external data calculation and import process. The correctness and
practicability of the method are verified by the welding experiment of saddle-shaped cylindrical intersection pipes.
Keywords Off-line programming .Welding .Spatial intersection curve .Visualization toolkit (VTK)
1 Introduction
In the field of welding engineering, there are many different
intersecting pipe structures, forming complex space intersec-
tion curve welding seam [1]. The welding task of these kinds
of space curves is widely exist in automobile, ship, steel struc-
ture, pressure vessels, and other manufacturing industries. For
complex space curve welding, arc welding robot teaching
programming not only takes a lot of time but also difficult to
guarantee the ideal position and posture of welding torch. In
order to overcome these shortcomings, robot off-line
programming technology has received extensive attention
and research in recent years.
At present, there are three kinds of off-line programming
methods for complex curve welding. The first method is to
directly rely on mature commercial off-line programming
software for application [2,3]. In particular, Robcad,
Robotstudio, and Roboguide are the most widely used, and
these commercial software can automatically generate high-
precision robotic programs according to the workpiece model.
However, these software products are expensive and have low
technology openness and, generally, only support robots pro-
duced by their own manufacturers.
The second method is to use the application programming
interface (API) provided by the general three-dimensional
CAD modeling software for secondary development. Mitsi
et al. [4] introduced an off-line programming system devel-
oped based on SolidWorks for welding operations. Zhu et al.
[5] presented a CATIA-based off-line programming system
for robot drilling in aerospace manufacturing. In addition, oth-
er modeling software such as AutoCAD and CAX also are
used for robotic welding off-line programming [6,7].
*Lei Hong
njithl@163.com
1
School of Automotive and Rail Transit, Nanjing Institute of
Technology, Nanjing 211167, China
2
Industrial Technology Research Institute of Intelligent Equipment,
Nanjing Institute of Technology, Jiangsu Provincial Engineering
Laboratory of Intelligent Manufacturing Equipment,
Nanjing 211167, China
https://doi.org/10.1007/s00170-019-04656-4
The International Journal of Advanced Manufacturing Technology (2020) 106:15871599
/Published online: 10 December 2019
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
... Yang et al. [21] studied off-line welding system of a single robot, including kinematic analysis, trajectory planning, and off-line simulation, and finally achieved the welding test. Hong et al. [22] introduced an off-line programming method based on VTK spatial intersecting curve and employed B-spline interpolation to discretize the welding trajectory, and the welding tasks were automatically completed. However, these studies only focus on the welding robot and do not consider the actual welding trajectory. ...
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The welding of spatial intersecting curves is widely used in the pressure vessels, in which the welding quality cannot be achieved by traditional methods. To this end, this paper proposes a novel methodology of dual-robot welding for the intersecting pipes by means of motion planning and off-line programming. This method takes advantage of the redundancy of the dual-robot system to obtain alternative paths for the collaborative welding task. Based on the mathematical model of the welding seam, the intersecting curve trajectory of the intersecting pipes is generated through the relevant mathematical theory and the MATLAB programming. The intersecting curve trajectory is decomposed into the welding trajectory and collaborative trajectory, and then imported into the RobotStudio simulation platform. The collaborative welding operation of dual-robot is finally achieved, which verify the effectiveness of the proposed methodology.
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