Abstract:

Aimed at the problem that the position and heading angle constrains of under-actuated unmanned surface vehicle (USV) cannot be taken into account at the same time in the position and attitude maintenance control, a strategy based on course constrains for the station keeping control of USV is proposed. First, a new fixed coordinate system based on the desired position and heading of USV is established. The coordinate system is divided into the reachable regions A and B, and unreachable region C. When the USV is in reachable region, it can return to the desired position and heading while it is able to avoid exceeding the desired heading angle range due to the inability to produce a lateral motion. Then different guidance strategies in different regions are used, which strictly restrict the course angle of the USV during the guidance process. Finally, the desired velocity and course angle are generated by the guidance strategy. The controller generates the execution and the USV quickly returns to the desired position and heading. The guidance strategy based on the course constraint incorporates the course constraint from the inner control into the outer guidance. As the USV implements different strategies in different regions, the desired position and heading and the inner loop control realize the station keeping of the USV. The outer loop guidance and inner loop control constraints are combined to take into account the under-actuated characteristics of the USV, which also simplifies the complexity of the controller design. The simulation experiments have proved the feasibility and effectiveness of the guidance strategy.

Key words: station keeping, unmanned surface vehicle (USV), guidance strategy