Efficient 3D Path Planning for Underwater Vehicle Based on Non-Uniformly Modeling

The paper focuses on the problem of 3D path planning for the underwater vehicle in an environment with obstacles. An efficient framework is presented where environment modelling and path planning are effectively performed to obtain a optimized feasible path. Firstly, octree is adopted to divide the spatial environment into grids non-uniformly. Hierarchical distances between adjacent grids in the tree are deduced and are then used to determine grid adjacent relationship. The environment modelling method would be helpful not only to reduce memory consumption but also to improve computational efficiency while maintaining modeling accuracy. Consequently, an improved heuristic search strategy is proposed by considering the features of underwater vehicle to obtain more feasible intermediate path points. Once all intermediate points are determined, they are globally optimized with a correction strategy and then, a cubic bezier curve is adopted to smooth the points. The resulting path satisfies nonholonomic constraints and makes the vehicle avoid obstacles autonomously. The proposed approach is tested on simulation and realistic underwater terrain scenes, proven to be efficient to generate feasible 3D trajectories with high real-time performance. The approach has important application value in the guidance of underwater vehicle.