Autonomous Welding Path Planning for Interference-Free Arc Welding

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Solution Overview

Problem

Current welding processes face challenges in optimizing weld quality for arc welding, as existing methods fail to accurately determine torch motion and welding conditions necessary for a good surface property and defect-free weld bead, and struggle to correct positional discrepancies between offline teaching and actual welding, especially in continuous line welding.

Innovation Solution

A welding path autonomous optimization system that includes a database, interference analysis part, and output part, using three-dimensional CAD data and quality-welding-condition correlation database to determine a welding path that avoids interference and ensures optimal weld quality by adjusting torch movement and power source conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If offline teaching analysis is used to avoid interference between welding torch and workpiece, then interference avoidance is improved, but weld quality optimization deteriorates

Engineering Contradiction:
Improveinterference avoidanceVSAvoidweld quality
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The system segments the welding process optimization into two independent modules: interference analysis (robot motion planning) and weld quality optimization (welding condition determination). This allows each module to be optimized separately while working together to solve the overall problem.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system introduces an intermediary database that stores welding condition information (torch tilt angle, welding speed, power source settings) separate from the robot motion data. This intermediary structure enables independent optimization of weld quality parameters without affecting interference avoidance calculations.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If coordinate correction is performed to correct positional relationship gap between offline teaching and actual welding, then positional accuracy is improved, but weld quality optimization deteriorates

Engineering Contradiction:
Improvepositional accuracyVSAvoidweld quality
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The system separates positional correction (coordinate transformation) from weld quality optimization. Coordinate correction handles only the geometric alignment between offline teaching and actual welding positions, while weld quality parameters are determined independently through database lookup based on welding conditions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system creates a virtual model of the workpiece from three-dimensional CAD data and performs interference analysis in this virtual space. This copying approach allows accurate positional relationship simulation without affecting actual welding quality parameters.

Inventive Principle:
Principle #26Copying

3Reliability

If robot motion coordinate analysis is used for avoiding interference, then interference avoidance is improved, but weld quality optimization deteriorates

Engineering Contradiction:
Improveinterference avoidanceVSAvoidweld bead shape and surface property
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The system divides the control parameters into motion parameters (robot position and orientation for interference avoidance) and welding parameters (torch tilt angle, welding speed, power source settings for quality optimization). Each set is independently determined and then combined.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system replaces traditional mechanical trial-and-error welding condition adjustment with an information-based database lookup system. Welding conditions are determined through information processing (querying the database based on welding type and position) rather than mechanical experimentation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS20240424611A1Welding path autonomous optimization apparatus, welding path autonomous optimization system, and welding path autonomous optimization method
Publication Date: 2024.12.26 HITACHI LTD
  • US20240424611A1 patent drawing
  • US20240424611A1 patent drawing
  • US20240424611A1 patent drawing

AI summary

The welding path autonomous optimization system includes a quality—welding-condition correlation database in which a constraint condition of welding by a welding robot that operates a welding torch is stored, an interference analysis part configured to determine a welding path that does not interfere with an object to be welded based on three-dimensional CAD data of the object to be welded and the constraint condition stored in the quality—welding-condition correlation database, and a welding-robot-operation/welding-condition output part configured to output welding process information based on the welding path.