A path planning algorithm for unmanned surface vessel with pose constraints in an unknown environment

To solve the problem of full-process path planning that includes multi-target path planning and automatic mooring, this paper proposes a hybrid D*Lite algorithm for an unmanned surface vessel with pose constraints (position and attitude) in an unknown environment. First, to solve the problem of multi-target path planning under the pose constraints, the D*Lite algorithm is combined with the Dubins search tree algorithm, and the corner at the sampling point is eliminated so that the path is smoothly connected. Second, to achieve the automatic mooring under the pose constraints and the avoidance of unknown obstacles, the D*Lite algorithm is combined with Reeds-Shepp curves to introduce the heading angle into the traditional two-dimensional search. This paper has conducted three groups of simulation experiments. In simulation experiment 1 and 2, compared with other algorithms in the multi-target points and automatic mooring environment for simulation experiments respectively, the D*Lite (Dubins) and D*Lite (RS) algorithm outperformed other algorithms in terms of planning time, planning distance, and smoothness. In simulation experiment 3, the effectiveness and superiority of the proposed method were verified on the grid map and compared with the traditional D*Lite algorithm. A visualization simulation was conducted, and the results revealed that the hybrid D*Lite algorithm enabled the unmanned surface vessel to efficiently achieve smooth movement with full-process throughout unknown environment.