Research And Design Of Variable Vector Propeller For AUV

As a new kind of propeller, variable vector propeller(VVP) can produce variable direction thrust by the cyclical change of blade pitch under the control of blade adjusting mechanism, and it can provide a good maneuverability for autonomous underwater vehicle(AUV) to conduct underwater survey tasks safely and effectively. The conventional propulsion mode usually consists of a normal propeller and the control device(such as, cross rudders or channel propellers), compared with that VVP has the advantages of compact structure, good maneuverability at low speed, continuous hull shape and low fluid resistance. So it has a very broad application prospect. Taking the blade adjusting mechanism of VVP as the core content of this paper, the contents are as follows:Firstly,after the analysis and comparison of existing blade adjusting mechanisms, a new eccentric-plate parallel blade adjusting mechanism was proposed, in which a Delta parallel mechanism was introduced to realize three sliding freedom of eccentric plate so that the blade pitch can be adjusted cyclically. And the feasibility of the mechanism was testified based on the geometry analysis and freedom calculation.Secondly, the kinematics and dynamics models of this mechanism were established and calculated based on vector equations and Newton-Euler method in the paper. We got the changing rule of blade pitch confirmed to the simple harmonic law, and the stresses of this mechanism were also obtained. The sizes of this mechanism were optimized to reduce the stresses of this mechanism, and the stiffness of the mechanism was improved as well.Then, to analyze the hydrodynamic performance of VVP, a VVP model was established in the paper according to the B-propeller charts, and the hydrodynamic simulation of this model was simulated with the computational fluid dynamics(CFD) software of Fluent. We got the hydrodynamic performance curves of VVP, namely the axial thrust, torque, transverse thrust and propulsion efficiency, which proved that VVP had a good maneuverability and propulsion efficiency.Finally, the detail structures of VVP were designed in the paper, then the strain and stress of VVP components were analyzed through the finite element software of ANSYS, and the structures of components were optimized according to the results of finite element analysis to insure components performance of structural strength, stiffness and so on.