I. Structural Components of a Welding Robot
1. The robot body is generally a 6-axis articulated manipulator driven by servo motors. It consists of a driver, transmission mechanism, robotic arm, joints, and internal sensors. Its task is to ensure the required position, posture, and motion trajectory of the robotic arm's end effector (the end effector).
2. Robot control cabinet: It is the nervous system of the robot switcher, including computer hardware, software and some dedicated circuits, responsible for processing all information and controlling all actions of the robot during operation.
3. Welding power switch, including welding power supply, special welding torch, etc.
4. Safety protection facilities for welding sensors and switches.
5. Welding fixtures and jigs.
For products with small batches, multiple varieties, and large volume or weight, simple welding robot workstations or robot workstations combining welding positioners and robots can be used, depending on the spatial distribution of the weld seams on the workpieces. This is suitable for flexible production with "multiple varieties and small batches." For products with small workpieces that are easy to transport, and with large batches and many varieties and specifications, the welding process can be subdivided, and a production line combining robots and specialized welding machines can be used, along with modular welding fixtures and quick mold change processes, to achieve low-cost automation with low investment and high efficiency.
II. Welding Robots: Two Methods
Currently, welding robot programming primarily relies on online teaching-in, although programmer interfaces have improved significantly, especially with the adoption of LCD graphic displays, making the programming interface of new welding robots more user-friendly and easier to operate. However, the coordinates of key points on the weld seam trajectory still must be obtained through teaching and then stored in the program's motion instructions. This requires a significant amount of time for teaching, especially for complex weld seam trajectories, reducing robot efficiency and increasing the workload of programmers. Currently, there are two solutions:
One approach involves roughly capturing a few key points along the weld seam trajectory during the teaching programming phase. The actual weld seam trajectory is then automatically tracked using the welding robot's vision sensors (usually arc sensors or laser vision sensors). While this method still relies on teaching programming, it reduces its complexity and improves programming efficiency to some extent. However, due to the inherent characteristics of arc welding, the robot's vision sensors are not suitable for all weld seam types.
Secondly, a completely offline programming approach is adopted, allowing the creation of the robot welding program, the acquisition of weld trajectory coordinates, and program debugging to all be completed independently on a single computer, without the robot's involvement. Offline robot programming has existed for many years, but due to limitations in computer performance at the time, offline programming software was primarily text-based. Programmers needed to be familiar with all the robot's instruction sets and syntax, as well as how to determine the spatial coordinates of the weld trajectory, making the programming work neither easy nor time-efficient. With the improvement of computer performance and the development of 3D graphics technology, most current robot offline programming systems can run in a 3D graphics environment. The programming interface is user-friendly and convenient. Moreover, the coordinates of the weld trajectory can usually be obtained using "virtual teaching-in," where the spatial coordinates of the point can be easily obtained by clicking on the welding area of the workpiece in the 3D virtual environment. In some systems, the weld trajectory can be directly generated from the weld position predefined in the CAD drawing file, and then the robot program is automatically generated and downloaded to the robot control system. This greatly improves the robot's programming efficiency and reduces the workload of programmers. Currently, commercial offline welding robot software based on ordinary PCs is available on the international market.
