Research On Tracking Control Of Underactuated Unmanned Surface Vessels

The high-speed surface vessels are typically underactuated systems with non-integrable constraints and external influence. The motion tracking control of position and orientation of underactuated surface vessels have received considerable attention recently. The motion tracking control for underactuated surface vehicles is especially challenging because most of these systems are not fully feedback linearizable. So it is very important to find advance intelligent control algorithm.In this paper, the three degree of freedom (DOF) planar kinematic and dynamic equations model of unmanned surface vessels is built through weakening complex conditions of uncertainty and external disturbances of the system. The Lyapunov stability theory and related theorems are introduced briefly. The key of analyzing the system stability with Lyapunov direct method is structing right Lyapunov function. However, Lyapunov direct method doesn't provide the general construction method of Lyapunov functions because of the lack of constructive and comprehensive. Therefor, the paper presents backstepping method. Backstepping realizes global regulation of the system or tracking control by the way of modifying the algorithm design step by step to stabilize the controller. Based on backstepping method the Lyapunov stability theory, the stability analysis and cosine tracking control is carried out. Besides, the adaptive control method based on the dynamic fuzzy neural network is proposed to realize the cosine tracking control. Simulation results prove that the simplified model system of unmanned surface vehicle is globally uniformly asymptotically stable. Then two tracking controller based on the backstepping and dynamic fuzzy neural network are designed and the cosine tracking simulation is carried out respectively in MATLAB/ Simulink environment. The simulation results show that the controllers both can achieve the designed tracing target.