Inspection of underwater structures with tethered underwater vehicles is often hindered by the risk of tether entanglement. We propose REACT (real-time entanglement-aware coverage path planning for tethered underwater vehicles), a framework designed to overcome this limitation. REACT comprises a computationally efficient geometry-based tether model using the signed distance field (SDF) map for accurate, real-time simulation of taut tether configurations around arbitrary structures in 3D. This model enables an efficient online replanning strategy by enforcing a maximum tether length constraint, thereby actively preventing entanglement. By integrating REACT into a coverage path planning framework, we achieve safe and entanglement-free inspection paths, previously challenging due to tether constraints. The complete REACT framework's efficacy is validated in a pipe inspection scenario, demonstrating safe navigation and full coverage inspection. Simulation results show that REACT achieves complete coverage while maintaining tether constraints and completing the total mission 20% faster than conventional planners, despite a longer inspection time due to proactive avoidance of entanglement that eliminates extensive post-mission disentanglement. Real-world experiments confirm these benefits, where REACT completes the full mission, while the baseline planner fails due to physical tether entanglement.

翻译：使用系留式水下航行器进行水下结构检测常因缆绳缠绕风险而受阻。本文提出REACT（面向系留式水下航行器的实时防缠绕覆盖路径规划框架），旨在克服这一局限。REACT包含一种基于几何的高效缆绳模型，该模型利用有向距离场（SDF）地图，可在三维空间中围绕任意结构对绷紧缆绳形态进行精确的实时模拟。该模型通过强制执行最大缆长约束，实现高效的在线重规划策略，从而主动防止缠绕。通过将REACT集成至覆盖路径规划框架，我们实现了安全且无缠绕的检测路径，这在以往因缆绳约束而极具挑战。完整的REACT框架在管道检测场景中验证了其有效性，展示了安全导航与全覆盖检测能力。仿真结果表明，REACT在保持缆绳约束的同时实现了全覆盖，且总任务完成时间较传统规划器快20%，尽管因主动避绕导致检测时间延长，但彻底避免了耗时的任务后解缠操作。真实世界实验证实了这些优势：REACT完成了全部任务，而基线规划器因物理缆绳缠绕而失败。