Energy optimal depth control for multimodal underwater vehicles with a high accuracy buoyancy actuated system

Abstract

Efficient depth control and energy consumption are significant factors that must be considered for underwater vehicles operating in deep-sea environments and for long-term deployments. This paper proposes a high-accuracy buoyancy-actuated system (HA-BAs) based on the energy optimization principle for multimodal underwater vehicles (MUVs), which can precisely regulate displacement to realize the efficient depth control. The proposed mathematical model in the vertical plane and the energy consumption model of the MUV with the HA-BAs were established, revealing all the regularities of motion control to improve the depth control precision and navigation efficiency. The depth control characteristics of the MUV with HA-BAs were analyzed by considering the operating in a practical environment, which showed that the HA-BAs facilitated a more precise depth control for the MUV. In addition, energy consumption per diving meter was used as an indicator of sailing efficiency. Energy efficiency and depth control analysis were carried out by motion simulation and sea trails, and the results indicate that the MUV employed HA-BAs is beneficial for energy saving and depth control, particularly in the Argo mode.