Estimation of equation of motion of four-rotor dish-shaped AUV and simulation research on its hydrodynamic characteristics

The four-rotor dish-shaped AUV is a new type of underwater vehicle. A three-dimensional model is set up to study the hydrodynamic characteristics of AUV, and the reference coordinate system and the generalized characteristic parameters are defined. In the body coordinate system, the concise six-degree-of-freedom dynamics and kinematics equations of motion for AUV are presented based on the momentum and the angular momentum theorem. The computational fluid dynamics method is used to simulate the hydrodynamic characteristics during the movement of AUV at the angles of attack from 0° to 90° based on fluid analysis software (Ansys CFX). The curves of drag, lift and pitching moment coefficients with the change of angle of attack are drawn. The simulated results show that, in the range of the angles of attack from 0° to 15°, the AUV is suitable for moving at a certain depth in the fluid with small fluid resistance. In the range of the angles of attack from 30° to 50°, the AUV is suitable to complete the curvilinear snorkeling motion with excellent lift characteristics.