Terminal Sliding Mode Control For Tracking And Formation Of Underactuated Surface Vessels

At present,the majority of ships at sea are still relying on the main propellers and rudders to propel and maneuver the ship,while the thrusters are only used at low speed for berthing.Therefore,only the longitudinal forces and transshipment torques generated by the propeller and rudder can be relied on when the motion of vessel in the three-degree-of-freedom is to be controlled.Such system is so-called underactuated system.For the underactuated system owns the properties of nonlinearity,non-integrity,model uncertainty and other characteristic,so how to solve these problems has become a hot topic in recent years and has a very important theoretical value.In this paper,the research of tracking and formation control of underactuated surface vessels has been carried out,and the main contribution of this paper are as follows:Firstly,by using terminal sliding mode control method(TSMC)method based on finite time stability theory,a novel decentralized robust controller is explored for underactuated vessels to tracking the trajectory of the target in a finite time.To avoid the singularity problem,an auxiliary sliding mode surface is introduced in the process of controller design.Simulation results are presented to illustrate the effectiveness of the proposed approach.Secondly,the formation control for underactuated surface vessels under external disturbances is studied.Under the leader-follower control frame,a formation controller for the underactuated surface vessels is designed based on algebraic graph theory,matrix theory and terminal sliding mode control method.Simulation results are given to illustrate the performance of the proposed scheme.Finally,this paper is summarized.The problems to be solved in the next research on tracking and formation control of underactuated surface vessels are proposed.