Research On Stationary Navigation And Fixed Operation Control Of Rescue ROV

With the increasing number of maritime transport activities and marine resources development,there are more and more accidents in the ocean.As a result,the demand for maritime search and rescue missions is increasing.Therefore,it is particularly important to establish a comprehensive search and rescue equipment system and improve search and rescue efficiency.Currently,underwater robots have gradually become the main force in underwater search and rescue equipments because of their advantages such as strong work ability,large amount of information exchanged in real time by man-machine,and the like.However,current search and rescue operations require the simultaneous use of AUVs(Autonomous Underwater Vehicles)and ROVs(Remotely Operated Vehicles)to complete search and rescue missions,mainly because AUVs do not have salvage operation capability,and the current development of ROV in high-speed navigation control accuracy is not the reason.Therefore,for search and rescue applications,we must study in-depth of underwater robot technology applicable to the search and rescue field and improve ROV's control accuracy at high-speed navigation and its anti-jamming capability at fixed-point operations,so as to have the ability of both "search" and "operation(recovery)" to directly meet the application needs of the entire process of search and rescue,and also is of great significance for streamlining search and rescue equipment and improving search and rescue efficiency.This dissertation takes the "HELLO ?" underwater robot as the research object,proceeding from the needs of the whole process of underwater search and rescue(large-scale scanning plus fixed-point salvage),and deeply analyzes the system parameters of ROV during high-speed navigation as the speed changes,as well as the low-damping inertia of the control system during fixed-point operation.And then this dissertation put forward different control strategies for ROV high-speed navigation and fixed-point operation conditions,which not only solves the problem of ROVs' poor control accuracy during high-speed movement,but also improves the anti-jamming performance of the ROV system at fixed-point operations,broadening the road for ROV applications in the search and rescue field.The chapters of this paper are distributed as follows:The first chapter mainly introduces the research background of this dissertation and the research status of underwater robot technology.It also gives a detailed overview of underwater robot motion control technology,thrust distribution algorithm and navigation and positioning technology,and proposes the research significance?the main research content and difficulties of this paper.The second chapter focuses on the search and rescue application requirements,analyzes the specific requirements of the search and rescue ROV in terms of hardware configuration,motion control performance,etc.,and on the basis of studying the constitution of "HELLO III" underwater robot system,focuses on the research of underwater robot movement.Controlling the mathematical model simplifies its six-degrees-of-freedom model based on actual and assumptions,and makes a quantitative study of the change of the control model when the ROV sails at high speeds,which paves the way for the following control theory design.The third chapter focuses on the research on the change and coupling of the hydrodynamic parameters with the speed of each degree of freedom when the ROV is navigating at high speed,and proposes an improved model-based S-plane control algorithm for speed control of high-speed navigation of underwater robots.And from the point of view of simulation experiments,the model-based S-plane controller can meet the requirements for the stability of underwater vehicle high-speed navigation.The fourth chapter mainly studies the stability of the hovering control of the fixed point operation of the underwater robot in the search and rescue process.The influences of water flow,manipulator movement and propulsion derating on the pose of underwater robot fixed-point operations are analyzed in detail,and the linear TDE-PD(Time Delay Estimation)is also discussed in detail.The controller design process demonstrates through simulation that the control performance of the linear TDE-PD controller is better than that of the pure PD controller.The fifth chapter summarizes the main work and innovation points of this paper,and puts forward the improvement method according to the shortcomings of the research.The fifth chapter completed the Zhoushan offshore test of the "HELLO III" underwater robot,focusing on the model-based improved S-plane navigation controller and linear time delay estimation for fixed-point operation heading and depth controllers.The control performance verifies the superiority of the control performance of the designed controller and basically satisfies the control accuracy requirements of the underwater machine search and rescue stages.The sixth chapter summarizes the main work and innovation points of this paper,and puts forward the improvement method according to the shortcomings of the research.