Research On Trajectory Tracking Of USV Affected By Wind Wave And Current

With the proposal of China’s "maritime power" strategy,USV has become an important member of the intelligent marine equipment industry.It has the advantages of light weight,fast speed,high autonomy and strong concealment.It shows great advantages in the face of some special tasks.High precision trajectory tracking is the basis for the USV to complete various tasks on the sea.In order to better study the motion control of the USV,this paper built the "Little Killer Whale" USV experimental platform,designed the software operating system based on ROS framework,and established the USV simulation model in gazebo,In addition,the control system of the "Little Killer Whale" unmanned boat was experimentally verified,and finally the research on the trajectory tracking of the unmanned boat was carried out in the Gazebo simulation environment.The main research contents of this paper are as follows:(1)Establish the "Little Killer Whale" experimental platform and simulation environmentFrom the perspective of experimental needs,the "Little Killer Whale" experimental platform was established.The hull was refitted from a small yacht.On the basis of the original,the throttle and steering electrical signal devices were modified,and various vision,depth sounder,radar and other various devices were added.sensor.The control system is divided into two parts: hardware and software.In hardware,a hardware control and communication system based on USB serial bus and network communication is designed.In software,an asynchronous communication system based on "topic" is designed with the help of ROS framework,which is verified by experiments.Feasibility of hardware and software systems.In order to facilitate debugging of the control algorithm,a simulation platform based on the "Little Killer Whale" was independently developed in the Gazebo simulation environment.(2)Establishment of wind,wave and current disturbance force model and threedegree-of-freedom mathematical model of USVFirst,a fixed coordinate system with the earth as the origin and a moving coordinate system with the ship’s center of gravity as the origin are established;secondly,by analyzing the force of the ship under the disturbance of wind,waves and currents,the wind,waves and currents are established.Finally,according to the experimental requirements,the kinematic model and dynamic model of the unmanned vehicle with three degrees of freedom are constructed,and the maneuvering response model of the unmanned vehicle is further deduced.And the model is verified by designing Z-shaped experiment and directional rotation experiment.The data obtained from the experiment is identified by AFSA algorithm,and the relevant parameters in the model are obtained.In order to further verify the accuracy of the parameters,an unmanned boat is designed.The heading controller is verified by experiments.(3)The design of the trajectory tracking controller of the USVFirstly,the principles of backstepping,sliding mode control and Lyapunov stability are briefly introduced.Then,aiming at the influence of wind,wave and current on the motion of USV,the motion model of USV and the interference force model of wind,wave and current are combined to construct the tracking error model.Finally,the error is stabilized by using backstepping sliding mode control and Lyapunov stability theory,and the trajectory tracking controller of USV is designed,the accuracy of the controller in different environments is verified in the simulation environment.