GLOBAL PATH PLANNING OF CLIMBING ROBOT FOR WELD QUALITY INSPECTION IN LARGE SCALE STORAGE TANKS

Abstract

Climbing robots are considered efficient solutions for conducting quality inspections of welds on large storage tanks. Nevertheless, planning the global shortest path along spatially complex cross distributed welds poses a significant challenge for climbing robots. This paper introduces a novel graph-based global shortest climbing path planning method, facilitating swift inspect all welds by the robot. The three-dimensional (3D) weld lines undergo conversion into a two-dimensional (2D) weighted connected graph using a 3D model equivalence mapping approach. The dimensionality-reduced connectivity map is required to be an Euler graph; otherwise, the adoption of the Floyd and KM algorithms is necessary to construct an undirected Euler graph with the minimum total weight. Subsequently, an Euler circuit is searched in the Euler graph, considering the presence of plus edges, through an improved Fleury algorithm to obtain the shortest global path for the climbing robot. The paper also introduces the idea of Euler graph segmentation to address the challenge of Euler circuits in large or symmetric models. Simulations are conducted to validate the effectiveness and performance of the proposed planners. The results demonstrate that our method effectively reduces the length global path and enhances inspection efficiency.