Infrared Vision Sensing for Narrow-Gap Weld Seam Deviation
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Solution Overview
Problem
Existing methods for detecting weld seam deviation in narrow-gap welding, such as those using infrared vision sensing, face challenges with low precision, limited application range, and poor engineering practicability, especially when dealing with varying groove gaps and asymmetric arcs during shaking or rotating arc welding processes.
Innovation Solution
An infrared vision sensing detection method and device that tracks the position changes of the welding wire relative to the groove side walls, using a digital infrared camera, an arc current sensor, and a computer image processing system to calculate weld seam deviation, allowing for high precision and adaptability to dynamic conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If single-side groove edge position detection is used, then the detection method is simple, but it is only applicable to cases where the groove gap is constant and has small application range
Solution Approach 1:
The detection method segments the groove into multiple regions (left groove edge, right groove edge, welding wire position) and detects each segment independently. By detecting both left and right groove edges and the welding wire position separately, the system can calculate weld seam deviation accurately regardless of groove gap variations, thus expanding application range while maintaining reasonable complexity
Solution Approach 2:
The detection system is designed to handle multiple welding scenarios (constant groove gap, varying groove gap, different arc positions) using the same basic detection framework. The method can detect groove edges and welding wire position universally, making it adaptable to various welding conditions without requiring different detection approaches
2Device complexity
If arc center is extracted according to geometric center, then the detection method is simple, but it is difficult to accurately reflect the actual rotating center of the arc due to arc asymmetry
Solution Approach 1:
The system introduces an intermediary reference point (groove center) that is easier to detect accurately than the arc center itself. By detecting the groove edges and calculating the groove center, then comparing the welding wire position relative to this stable reference, the system achieves accurate weld seam deviation measurement without being affected by arc asymmetry or difficulty in locating the true arc center
3Device complexity
If CCD camera is used for arc center detection, then the detection method is simple, but the camera has small dynamic range and low response speed
Solution Approach 1:
The system replaces the mechanical/optical approach of using a CCD camera to directly capture and process arc images with an electrical sensing approach. By using arc current sensors to detect changes in arc current that occur when the arc contacts groove edges, the system achieves much faster response speeds while maintaining simplicity in the overall detection framework
4Productivity
If single-side edge position information is extracted, then the processing is simple, but the method is not suitable for low-frequency swing arc welding applications
Solution Approach 1:
The detection system continuously monitors both left and right groove edges and welding wire position throughout the arc swing motion. By maintaining continuous detection of all relevant positions rather than taking single snapshots, the system can accurately track weld seam deviation even at low frequencies where the arc moves slowly, ensuring the useful detection action continues without interruption
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 solution provides high detection precision, strong environmental adaptability, and improved real-time performance for weld seam deviation detection, applicable to both shaking and rotating arc welding scenarios with varying groove gaps, and is not limited by asymmetric arcs or low-frequency arc movements.
Implementation Method 1
a digital infrared camera... obtains, by means of sampling triggering, welding images when the arc rotates to positions on the left and right side walls of a groove
Data Source
AI summary
An infrared vision sensing detection method and device for narrow-gap weld seam deviation are provided. The device includes a shaking (or rotating) arc narrow-gap welding torch, an arc current sensor, a computer image processing system, and an infrared photographing system. The infrared photographing system includes an infrared camera which acquires an infrared image of a welding region in an external triggering manner when an arc shakes (or rotates) to a position closest to the left side wall or right side wall of a groove. After computer image processing, a welding wire position and a groove edge information is extracted in real time, and a weld seam deviation is calculated according to position changes of a welding wire relative to the left side wall and the right side wall of the groove, and the weld seam deviation is output. During pulsed arc welding, a signal in a base value period of the arc current pulse is detected by using the current sensor, thereby realizing welding image acquisition synchronized with the base value current period of the pulsed arc.