Design Of The Variable Buoyancy System Of AUV And Research Of The Control Strategy

With the continuous development of high-tech,the equipment for human exploration and utilization of marine resources is also constantly updated.As a marine exploration platform,the technical level and performance of AUV are becoming more and more mature.However,complex marine surveys and marine engineering tasks require AUV to navigate further,which means reducing energy consumption as much as possible with a certain amount of energy.At present,most of the AUV are positive buoyant for safety,and due to the change of ocean density and other factors,the total buoyancy amount is relatively large,therefore,there is a balanced rudder angle and a direct attack angle,increasing resistance and energy consumption.Therefore,this paper designs a variable buoyancy system.Taking the active adjustment of small displacement as the principal thing,the precise adjustment is achieved.It has the advantages of high reliability,small volume and weight.A depth control strategy based on this variable buoyancy system is proposed,which reduces the rudder angle and the attack angle significantly.The main contents and results are as follows:Factors of the existence of a balanced rudder angle and a direct attack angle are analyzed,which ensures the necessity of VBS.The influential factors of maximum buoyancy regulating volume relating to the change of water density and compression of shell are studied,and maximum buoyancy regulating volume is determined.Hydraulic principle diagram of the variable buoyancy system is simulated dynamically by AMESim software to verify the feasibility of components.Then experimental platform of the variable buoyancy system is built.The relevant parameters are tested and compared with the simulation results to verify the validity of the simulation,and to provide a guarantee for the variable buoyancy system at the same time.The AUV motion model and the dynamic model are established,and the hydrodynamic coefficients of the vertical plane are obtained by CFD,semi theoretical and semi empirical methods.AUV simulation model,buoyancy regulation model,control model are built.AUV depth control strategy based on buoyancy regulation is proposed.Then set up the control model by using Simulink software.Progressiveness of depth control based on variable buoyancy system is verified.