Welding Torch Weaving Sampling for Pulsed Arc Seam Tracking
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Solution Overview
Problem
The accuracy of through arc seam tracking in robotic electric arc welding is compromised by welding waveforms with pulse portions, due to frequent changes in welding current levels, which existing technologies fail to adequately address.
Innovation Solution
A robotic electric arc welding system that includes a welding torch, a robot controller for controlling weaving movements, and a welding power supply that samples weld parameters to generate a weld quality score, automatically adjusting the sampling period based on weave frequency or torch position information, and records through arc seam tracking information to calculate corrections to the weld path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If welding waveforms with pulse portions are used to control welding current levels, then welding quality can be improved, but the accuracy of through arc seam tracking deteriorates due to frequently changing current levels
Solution Approach 1:
The system dynamically adjusts the sampling period based on the weave frequency and torch position. During weave welding with pulse waveforms, the sampling period is extended to complete weave cycles to capture stable current levels, rather than using fixed short intervals. This dynamic adaptation allows accurate tracking despite frequent current changes from pulse portions.
Solution Approach 2:
The system pre-establishes the relationship between weave frequency, weave period, and optimal sampling period before actual welding. The robot controller communicates weave parameters to the power supply in advance, enabling the power supply to prepare appropriate sampling intervals that account for the periodic nature of weave welding and pulse waveforms.
2Device complexity
If fixed sampling periods are used for monitoring weld parameters, then system complexity is reduced, but the accuracy of weld quality assessment deteriorates when weave frequency varies
Solution Approach 1:
The sampling period transitions from a fixed value to a dynamic parameter that adapts to weave frequency. The power supply receives weave frequency information from the robot controller and automatically calculates appropriate sampling periods, ensuring accurate weld quality assessment across varying welding conditions without requiring complex manual configuration.
3Speed
If sampling period is shortened to capture rapid current changes in pulse waveforms, then response speed improves, but measurement accuracy deteriorates due to noise and instability during current transitions
Solution Approach 1:
The system leverages the periodic nature of both pulse waveforms and weave welding by synchronizing sampling to complete weave cycles. Instead of sampling at fixed high-frequency intervals that capture unstable transition periods, the system samples at periods that align with complete weave cycles, capturing stable current levels at consistent phases of the weave pattern.
Data Source
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AI summary
A robotic electric arc welding system (300) includes a welding torch (304), a welding robot (302) configured to manipulate the welding torch (304) during a welding operation, a robot controller (308) operatively connected to the welding robot (302) to control weaving movements of the welding torch (304) along a weld seam and at a weave frequency and weave period, and a welding power supply (310) operatively connected to the welding torch (304) to control a welding waveform, and operatively connected to the robot controller (308) for communication therewith. The welding power supply (310) is configured to sample a plurality of weld parameters during a sampling period of the welding operation and form an analysis packet, and process the analysis packet to generate a weld quality score, wherein the welding power supply (310) obtains the weave frequency or the weave period and automatically adjusts the sampling period for forming the analysis packet based on the weave frequency or the weave period.