Automated path‐planning strategy for robotic inspection of underground utilities based on building information model

This paper proposes a fully automated end-to-end inspection-path-planning strategy for underground utilities, such as pipelines, based on building information modeling (BIM). An automatic extraction method is developed to process utility information from BIM models, using a registration step that pairs each pipeline with its corresponding utility branch. This is followed by geometric modification via offset algorithms that account for obstacle dimensions to generate safe navigation paths. A novel inspection algorithm, the utility-Chinese postman problem (U-CPP), is introduced to generate a topological map and ensure full-coverage inspection. A Dynamo prototype integrates all these algorithms, minimizing manual intervention and achieving full-process automation. The method is validated with three real-world utility BIM models featuring diverse cross-sectional configurations. The U-CPP algorithm achieves 100% coverage with minimal repetition rates and computes optimized inspection paths in 24, 23, and 23 ms. Results demonstrate that the proposed strategy efficiently automates both information extraction and full-coverage path planning. The U-CPP algorithm proves to be robust, computationally efficient, and effective in handling diverse utility configurations.