Design And Optimization Of Buoyancy Drive System Of Self-supported Deep-sea Profile Buoy

As a kind of underwater exploration robot,deep-sea section buoy plays an important role in the exploration of Marine resources and the prediction of Marine environment and climate.In addition,the deep-sea buoy has the advantages of long endurance and low cost compared with other underwater robots.Buoyancy regulation system is the driving device of the buoy.In order to improve the endurance and stability of buoy,the buoyancy driving system is designed and optimized in this thesis.In this thesis,the buoyancy regulation system were designed according to the performance requirements of the deep-sea buoy.The total oil saving of the buoyancy drive system was calculated and the temperature rise of the hydraulic system was checked.According to the relation between the inlet pressure of plunger pump and the saturated vapor pressure of hydraulic oil,the mathematical model of inlet pressure was established.When the inlet pressure of the plunger pump is lower than the saturated vapor pressure of the hydraulic oil,cavitation is easy to occur,thus reducing the volumetry efficiency of the plunger pump.In order to improve the volumetric efficiency of the plunger pump and meet the requirement that the hydraulic oil in the outer oil tank can flow back to the inner oil cylinder under the surface of the sea.The influence of the parameters such as vacuum degree of ballast tank,pipe diameter of oil suction line and spring stiffness on the inlet pressure of the plunger pump was analyzed,and their value range was calculated.Secondly,according to the working principle of the hydraulic system,the simulation model of the buoyancy regulation system was established by using the hydraulic library,mechanical library,signal library and HCD library in AMESim.The HCD modeling of internal cylinder,motor and plunger pump was carried out to make the simulation result closer to the test result.The parameters of the simulation model are set according to the actual parameters.At the same time,according to the calculation results,the flow rate and pressure in the process of oil discharge and oil return of the hydraulic system under different parameters were simulated and analyzed by batch operation.At the same time,the optimization model is established using AMESim.NLPQL algorithm is adopted for optimization.By setting the initial value and value range of the variable,the objective function can be minimized,and the optimal solution to maximize the efficiency of the buoyancy regulating system can be explored.Finally,the reliability of the hydraulic system was tested by building a circulating pressure system.By comparing the experimental data with the simulation results,the rationality of the parameter setting of the simulation model is verified,which lays a foundation for further optimizing the buoyancy regulation system.The research content of this paper saves the design time,reduces the design cost,improves the oil discharge efficiency of buoyancy drive system,and enhances the endurance of section buoy.