Resumen
In recent years, hybrid unmanned aerial underwater vehicles (HAUVs), which are capable of air?water trans-media motion, have been increasingly developed. For most HAUVs, air?water trans?media motion is a relatively dangerous and difficult process. Therefore, it is of great significance to study the particular process. This paper presents the first study on the kinematic stability of the air?water trans?media motion of HAUVs. First, a simplified dynamic model of HAUVs is proposed, including the hydrodynamic forces and the time?varying buoyancy. Then, based on the proposed model and the Hurwitz method, this paper derives the air?water trans?media kinematic stability criterion for HAUVs. This criterion can be applied to most air?water trans?media motions that satisfy the assumptions in this paper. Finally, this paper takes ?Nezha?, a novel HAUV, as an example to analyze its air?water trans?media kinematic stability. The results show that the proposed criterion is effective in judging the vehicle?s design, including the geometry and thruster power, which are important factors in the performance of the trans?media process.