Sailing Efficiency Analysis and Experiment of an AUV with a Buoyancy Regulation System

The sailing efficiency of autonomous underwater vehicles (AUVs) is a main performance index for ocean observation and exploration. However, the weaknesses or lack of buoyancy regulation capability makes AUV's endurance susceptible to the seawater density, especially at areas with temperature jumps or salinity jumps. To solve that problem, this paper proposes a dual-mode buoyancy regulation system by combining the advantages of gas and liquid, which can control larger displacement volume than liquid itself and make it synchronize with the seawater density at different depths. Firstly, based on the dynamic model and energy model, the relationship between the endurance of AUV and the control parameters of the buoyancy regulation system is obtained. Then, sea trials of AUV were conducted and validated performance of the dual-mode buoyancy regulation system, effectiveness of the energy model, which make a 32% reduction in energy consumption and an 11% increase in single-profile range after the optimization, which can provide guidance for improving the endurance performance of other underwater vehicles.