Research On Track Control Of Unmanned Surface Vehicle Based On Hybrid Propulsion

Recently,with the world's ever-increasing population,the environment and energy issues are drawing more and more attention.Accordingly,as a major tool for exploring and exploiting the marine resources,the unmanned surface vehicle has got the rapidly development.The fuel cell hybrid power USV,with vast development and application prospect,is the product of combining the unmanned driving technology and the new energy technology,which has the characteristics of zero emission,high efficiency and fast start-up.Autonomous dynamic collision avoidance,track control and energy management strategy are the critical technologies to improve the security,stability and intelligent degree of USV's autonomous navigation.However,current researches have some difficulties,including constraints of maneuvering characteristics,the requirements of real-time performance of controller,the problem of the durability of fuel cell,etc.To solve the problem above,this thesis takes the fuel cell hybrid power USV as the research project and makes the researches on autonomous dynamic collision avoidance,track control and hybrid power system of USV.The main tasks of this thesis are as follow:(1)The establishment of the USV maneuvering model.In this paper,a practical underactuated USV with high speed navigation is taken for example,and the 6-DOF maneuvering model is established.Considering that damping coefficients change greatly with USV's high speed,the 3-DOF maneuvering model including nonlinear damping terms of underactuated USV is obtained,which lay a foundation for the simulation researches of autonomous dynamic collision avoidance and track control.(2)Research on autonomous dynamic collision avoidance method.Aiming to solve the problem of obstacle avoidance of the USV with multiple constraints of COLREGS and maneuvering characteristics,an autonomous dynamic collision avoidance method of the USV based on set-based guidance and dynamic window constraint is proposed.This method considers the COLREGS and can get a feasible collision avoidance path which meets the requirements of the USV maneuvering characteristics and the COLREGS quickly.Simulation results show that the method can effectively avoid the obstacles under the premise of conforming to COLREGS.(3)Research on track control.Aiming at the problem that model predictive control is difficult to meet the requirements of real-time performance for the actual trajectory tracking system of USV,for the reason of high online computational complexity,a track control method based on explicit model predictive control is proposed.In order to transform the tracking control to the heading control,the reference yawing angle is determined by LOS guidance.At the same time,the explicit model predictive control is employed for the heading control which can reduce the online computing time of the controller.The simulation results show that the real-time performance of track control can be greatly improved based on this method.(4)Research on energy management strategy of hybrid power system.Aiming at the prototype ship powered by Diesel engine,a hybrid power system is designed with the fuel cell and the battery as the main and auxiliary power source.The topology of the system is determined and the parameters of every components are obtained by doing matching calculation.Aiming at the problem of the durability of fuel cell,an improved fuzzy logic control which increases the control requirements is designed.The simulation results under the operating conditions show that the improved fuzzy logic control can improve the durability of fuel cell effectively.A comprehensive study of autonomous dynamic collision avoidance,track control and energy management strategy is conducted in this dissertation.The research results have important academic and engineering application value,which can promote the development of hybrid power USV.