Online Receding Horizon Trajectory Planning Method for UUV Near Bottom Terrain Tracking

Seafloor terrain survey is an important appliance for unmanned underwater vehicle (UUV). In this paper, online receding horizon trajectory planning method is present to realize good effect of near bottom tracking when UUV performs the seafloor terrain survey task. Considering that the task process has the characteristics of real-time control and dynamic periodic planning, a three-loop feedback framework of planning, tracking and controlling is proposed. The framework has the advantage that the slow trajectory planning loop and the fast real-time tracking control loop are unified. Based on the framework, the online receding horizon planning strategy and algorithm are designed to realize dynamic trajectory planning when UUV tracks seafloor terrain. For outer loop of trajectory planning, the Bezier smoothing fitting method used to generate the online trajectory based on the real-time detection information of seafloor terrain. At last, the validity and feasibility of the proposed online trajectory planning framework and method are verified by the simulation results.