关键词: 水空跨介质, 可重复出入水, 四旋翼布局, 回转折叠结构, 水下航行

Abstract: Cross-medium vehicles capable of operating in both aquatic and aerial environments have significant potential for applications in ocean monitoring, rescue operations, resource exploration, and environmental protection, making them valuable in a wide range of fields. This paper presents the design of a rotary-wing vehicle with foldable arms, codenamed "Feiyi," which can operate in three distinct modes: underwater cruising, surface navigation, and aerial flight, with the ability to transition between air and water multiple times. In terms of overall design, "Feiyi" utilizes a rotary body structure to minimize hydrodynamic resistance during underwater motion and to reduce storage space when retracted. The vehicle features a propulsion system with four rotors at the front for flight control and four thrust-ers at the rear for underwater attitude and movement control. To optimize efficiency in both water and air, "Feiyi" adopts a horizontal posture for underwater navigation and a vertical posture for aerial flight, with attitude adjustments during medium transitions managed by a combination of thrusters. A prototype was developed and tested in various operational modes, including underwater navigation, surface cruising, cross-medium transitions, and aerial flight. The experiments demonstrated that "Feiyi" can achieve a flight altitude of 30 meters with a height control precision of ±0.1 meters and an angular control precision of ±0.5°, representing a significant improvement in control accuracy com-pared to existing vehicles.

Key words: Cross-medium Aerial and Underwater, Repeated Water Entry and Exit, Quadrotor Layout, Rotary Foldable Structure, Underwater Navigation