Robot Welding Alignment Using Slit Laser Line Misalignment Correction
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Solution Overview
Problem
Existing robot systems face challenges in accurately aligning and correcting the level difference between adjacent workpieces during corner joint welding, which affects the quality of the weld.
Innovation Solution
A robot system that includes a robot, an illumination device, a camera, and a robot controller. The system uses a slit-like laser beam to form line images on the surfaces of the workpieces, and the camera captures these images. The robot controller processes the images to determine the misalignment amount and direction, and adjusts the position of the second workpiece relative to the first workpiece to correct any level differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a slit-like laser beam is radiated onto both plate materials from diagonally above to determine optimal welding position, then welding quality is improved, but the complexity of the alignment system increases
Solution Approach 1:
The patent introduces a camera as an intermediary device to capture images of the slit-like laser beam projected onto the workpiece surfaces. The robot controller then processes these images to automatically calculate misalignment amounts and generate correction instructions, mediating between the laser alignment system and the robot positioning system to reduce overall system complexity.
Solution Approach 2:
The patent replaces manual mechanical alignment operations with an automated optical measurement and image processing system. The camera captures visual information of the laser beam position, and the robot controller automatically computes and applies corrections, substituting complex mechanical adjustment mechanisms with a more manageable optical-electronic system.
2Measurement precision
If the camera captures images from a direction inclined with respect to the plane to measure misalignment, then measurement accuracy is improved, but the difficulty of detecting and measuring increases
Solution Approach 1:
The patent positions the camera to capture images from an inclined direction rather than perpendicular to the workpiece plane. This introduces a dimensional advantage where the perspective view allows the camera to simultaneously capture both the laser beam position and the workpiece surface geometry, enabling accurate misalignment measurement that would be difficult with top-down imaging.
3Manufacturing precision
If the robot controller performs correction of level difference between workpiece surfaces, then welding quality is improved, but the operation time increases
Solution Approach 1:
The patent performs misalignment detection and correction calculations before the actual welding operation begins. The camera captures the laser beam position, the controller calculates the misalignment amount, and generates correction instructions in advance, allowing the robot to pre-position the workpieces correctly before welding starts, thereby minimizing time loss during the welding process itself.
Solution Approach 2:
The patent implements a feedback loop where the camera continuously monitors the laser beam position on the workpiece surfaces, the robot controller calculates misalignment corrections based on captured images, and the robot applies position adjustments. This closed-loop feedback system enables efficient, automated correction that reduces overall alignment time compared to manual iterative adjustments.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively corrects the misalignment between the workpieces, ensuring optimal alignment for butt welding and improving the quality of the weld.
Implementation Method 1
an illumination device that radiates a slit-like light beam onto surfaces of the first workpiece and the second workpiece
Implementation Method 2
a camera that captures, from a direction inclined with respect to the plane, an image containing a first line image of the light beam formed on the surface of the first workpiece and a second line image of the light beam formed on the surface of the second workpiece
Data Source
AI summary
A robot system including: a robot that grips one of a first and second workpiece that are disposed adjacent to each other; an illumination device that radiates light beam onto surfaces of the first workpiece and the second workpiece on either side of a border between the workpieces along a plane that intersects the border; a camera that captures an image containing a first line image of the light beam formed on the surface of the first workpiece and a second line image of the light beam formed on the surface of the second workpiece; and a robot controller that operates the robot based on a misalignment amount and direction of the second line image with respect to the first line image in the image acquired and that performs a correction of a level difference between the surface of the first workpiece and the surface of the second workpiece.