Nezha-H: An HAUV for Aerial and Underwater Observation and Sampling

Hybrid aerial underwater vehicles (HAUVs) provide unique capabilities for aerial and underwater observation and sampling, with a variety of configurations already developed. However, challenges in maneuverability, payload integration, and practicality persist, while their specific applications remain underexplored, limiting the full realization of their potential. This letter introduces an aerial and underwater observation and sampling (AUOS) system, featuring a Nezha-H HAUV and an autonomous water sampler. The Nezha-H fuses an H-shaped quadrotor configuration with a T-shaped quad-thruster mechanism, enabling mobility across air, surface, and underwater environments, with vertical profiling sampling capabilities. The static and cruise stability of Nezha-H on the surface and underwater are also analyzed through theory and experiment. The intelligent multi-water sampler automatically detects the thermocline and collects water samples at specific depths. This feature enables speedy and precise observations and sampling in a wide variety of aerial-aquatic environments. Successful trials in the field demonstrate its versatility in vertical sampling, thermocline identification, and air-water interface observation.