Modeling And Verification Of A Sterndrive Unmanned Surface Vessel

Unmanned Surface Vessel(USV)is an autonomous platform that can accomplish specific missions based on multiple functional modules in the marine environment.It plays an increasingly important role in many fields such as military,hydrological surveying,rescue-salvage and etc.Distinguished from general large scale ship,USV has small size,light weight,high speed,and is vulnerable to the disturbance of marine environmental such as wind,waves,current and etc.Therefore,in the face of the complex and unknown marine environment,it is one of the important researches on autonomous motion control of the USV to establish a reasonable maneuvering model and accurately identify its model parameters.In this paper,the "LANXIN" USV of Dalian Maritime University is taken as a research object.Aiming at a kind of USV's propeller,modeling of characteristics of maneuvering motion,identifying research and experiment of real ship are in process.The main research content is divided into following sections:Firstly,the reference frame of USV is established,and the maneuvering math model is divided into two parts:kinematics modeling and dynamics modeling,and the environmental interference models of wind,wave and current are established.Aiming at the propulsion system of USV,the mathematic model of propulsion system of USV are established by analyzing the thrust of propulsion system and thruster.Secondly,the three degrees of freedom maneuvering model of USV are established.With the modeling method of the separation model and the structural characteristics of a type of maneuvering propeller,a first and second order linear response model and nonlinear response model describing the relationship between input and output of“LANXIN" USV maneuvering motion,which laid the theoretical foundation for model parameter identification.Finally,a model identification and verification platform for "LANXIN" USV is designed.The model parameter identification method based on recursive least square method is adopted.According to a large number of real ship maneuvering motion data,the relevant parameters of USV's three degrees-of-freedom maneuvering motion model and thrust system are identified,meanwhile,the parameters of the linear response model and the nonlinear response model of USV are identified.Based on the above identified model parameters,a maneuvering simulation platform for USV are built.The comparison between the experimental data and the model simulation data and the analysis of maneuvering motion characteristics were carried out to verify that the correctness of the mathematical model of motion and the identification of the model parameters of the US,which provides a reference for the USV's research.