Research On Area Keeping Control Method Of Unmanned Surface Vessel

Unmanned surface vessel(USV)is a kind of high performance ship with advanced technology such as autonomous path planning,trajectory tracking,environmental perception,target detection and identification and so on.USV has characteristics of high-speed,stealthy hull and high intelligent,so it is widely used in both the civilian fields and military fields.In recent years,with the rapid developing and application of USV,USV is usually stricted to work in a designated operation area.So study on the area keeping control method of USV will be of great importance.However,there are two great difficultis in the design of area keeping controller for USV.On the one hand,traditional nonlinear control theory can not apply to USV due to the underactuation of USV.On the other hand,USV is sensitive to the external environment disturbance because of its relatively simple equipments.Therefore,it is necessary and challenging to propose simple and effective area keeping control method of USV.In this paper,two different area keeping controllers of USV aimed at corresponding target requirements are designed,respectively.The content of the thesis is arranged as follows:Firstly,the background and meaning of the project is expounded,and the research status of USV technology and area keeping technology is introduced.The structure of the paper is given.Secondly,according to the MMG modeling ideas,the 6DOF movement control mathematics model of USV is established.Then,the model is simplified to a 3DOF model under suitable assumptions.The simplified mathematics model of USV is built based on MATLAB and verified to be effective and feasible by simulation.Then,in order to meet the strict limited condition of the operation area of USV,an area keeping control method based on barrier Lyapunov function(BLF)and sliding mode control(SMC)is proposed.Firstly,a trajectory tracking SMC controller of USV is designed to achieve the foundamental motion control.Then,BLF is combined to strict the position states of USV,and the area keeping controller based on BLF and SMC is designed.Stability analysis shows that the position states of USV can be stricted in given range,and the simulation results verified the effectiveness of the controller under environment disturbance.Finally,considering the limited energy and the wear of actuator,in order to reduce energy consumption and the wear of actuator.An area keeping control method based on Minimum Energy Consumption(MEC)is studied.Firstly,a weather optimal area keepingcontroller is designed.Under the controller,the USV can stay in the operation area with the weather optimal heading,which can reduce energy consumption to a certain degree.To further reduce energy consumption,an improved weather optimal area keeping switching control method is proposed.The simulation results show the effectiveness and superiority of the proposed method in energy consumption.