Collision-free path planning for multi-pass robotic welding

Welding joints for offshore oil rigs present a complicated geometry and require multiple passes. This paper introduces a complete collision-free offline path planning approach for such joints. Collision detection is performed using A* search on a three dimensional grid, where triangular mesh representations of the welding joint and its fixture form the objects. A workflow is proposed for the complete planning process which involves two primary steps; multi-pass planning and intermediate path planning. The paper demonstrates results on a `brace-to-chord' joint, which illustrates the feasibility of the proposed approach.