A Novel Fixed-time-based Unmanned Surface Vehicle Autonomous Berthing Sliding Mode Control

The development of autonomous berthing system is the key to realize vehicle autonomous navigation system. Accurate trajectory tracking is crucial for autonomous berthing of unmanned surface vehicles(USVs). In this paper, a novel fixed-time autonomous berthing sliding mode control scheme is proposed, which introduces the fixed-time into the design of sliding mode surface. Compared with the traditional method, this method not only keeps the advantage of avoiding singularity, but also has faster convergence performance, and the convergence time is bounded by a constant, independent of the initial state. In addition, the discontinuous terms of the existing control algorithm are replaced with non-smooth terms to completely eliminate chattering. Finally, the simulation and comparison experiments show that the proposed control scheme is better than the typical control scheme.

I. Introduction

With the rapid development of vehicle science and technology, the potential applications of unmanned surface vehicles(USVs) in military patrol, environmental monitoring, maritime search and rescue have been developed [1] [2] [3], with the advantages of safer, more efficient and energy-saving. Autonomous intelligent USV is the hot direction of future development. At present, it has made great progress in open waters, but it cannot achieve full autonomy in port berthing [4]. The complex port environment and unknown external environment interference put forward higher requirements for autonomous berthing technology. Therefore, it is of great significance to study the autonomous berthing technology of USVs to realize the high degree of autonomy in the whole mission cycle.