Design And Experiments Of Buoyancy-driven System Of Full Ocean Depth Autonomous Underwater Glider

Abyssal science is one of the hotspots of current marine scientific research,which attracts lots of marine science and technology researchers around the world,therefore various types of full ocean depth submersibles are being developed.The autonomous underwater glider(AUG)is a kind of mini-submersible being famous for its low energy consumption,low noise and low cost.Expanding the working range of AUG to the full ocean depth and developing it into an abyssal research platform are of great significance to the development of deep-sea exploration equipments.As the power source of the AUG,buoyancy-driven system is indispensable for the AUG to work in the full ocean depth.In this thesis,a full ocean depth buoyancy-driven system was designed based on existing research status of deep-sea buoyancy-driven system.And the feasibility and deep-sea adaptability of the buoyancy-driven system were verified by software simulation analysis and experimental tests.In addition,the optimization of system performance are realized through the research on the layout of spherical buoyancy-driven cabin of full ocean depth AUG.The main contributions of this paper can be summarized as follows:1)The buoyancy-driven system of the full ocean depth AUG was designed and developed,and its first deep dive test with a depth of 8213 m has been successfully carried out in the Mariana Trench.2)The buoyancy-driven system scheme with high efficiency and good buoyancy adjustment capability is proposed,the sealing problem under high seawater pressure is solved,and the plunger pump and electric motor can match well.What’s more,the component selection,auxiliary design and performance verification of the buoyancy--driven system are completed.3)Based on AMESim hydraulic simulation software and the self-built system test platform,the buoyancy-driven system is fully tested.The basic characteristics of system such as pressure,flow rate,pump speed and torque are analyzed by comparing the simulation data with the test data to verify the reliability and stability of the system.Besides,the tests are carried out under different external pressure,speed of pump and working mode of system to find out change law of system characteristic parameters.These conclusions are beneficial for improving system efficiency and reducing system energy consumption.4)The spherical cabin layout model based on the finite sphere enveloping method is established to optimize the layout of the buoyancy-driven system of full ocean depth AUG.And after several iterations of improved genetic algorithm,the optimal solutions are obtained.Through this optimization,both the space utilization and the piping layout of buoyancy-driven cabin are improved.Besides,the mathematical model combines the layout of hydraulic components with the optimization of pipelines,which can effectively solve layout optimization problems with components and connecting pipes.This method can provide a reference for solving similar problems.