Time and Energy Optimal Path Planning of USV Under Time-Varying Ocean Currents

An unmanned surface vessel (USV) is often deployed to operate for a long time, but considering that the energy of an unmanned ship should meet the index of long-term endurance, the path-planning technology of the USV needs to be further developed when the USV navigates in the complex time-varying ocean current environment. In this paper, path planning methods based on the Dijkstra algorithm which considers time or energy optimal search are employed. Firstly, the mathematical model that consists of the time-varying ocean current description, the motion model of USV, and the cost function model are introduced. The cost function model established includes the time cost function and the energy cost function. Secondly, the Dijkstra algorithm is utilized to solve the time or energy-optimal search problem. The effectiveness of the proposed path planning methods of USV is verified by simulation in Matlab, in which the electronic chart of the ocean is given and the time-varying ocean current environment is established. In addition, GUI is designed to facilitate operation and display search results. The simulation results show that the path planning method can effectively generate the global path according to the optimal time or energy object.