Research On Spatial Tail-swing Propulsion System

Underwater vehicle has always been the research hotspot of modern underwater artificial machinery.As one of the main propulsion techniques of underwater vehicle,the tail-swing propulsion technique has attracted much attention.Among these techniques,the high thrust and efficiency straight line parade propulsion mode with the crescent caudal fin has become the focus of our research.However,there have been no satisfactory research plans for maneuverability such as turning and lifting.Therefore,in this paper,based on the relationship between two kinds of tail-swing propulsion models and the propulsion performance,a spatial tail-swing propulsion model is proposed.From the aspects of kinematics,hydrodynamics,prototype design and experimental,the study on the preliminary theory and propulsion performance of the spatial tail-swing propulsion system is carried out.The main research contents are as follows:1.Through the analysis of two swimming models of carangiform and cetaceans,the interrelationships between the motion posture and the motion parameters in different swimming states were explored,focusing on the analysis of turning maneuver performance of carangiform propulsion model and the analysis of the diving performance of cetaceans propulsion model.On this basis,he mathematical motion model of the conical motion domain under the process of spatial tail-swing is created,the equation of the relation between the motion parameters and the conical motion domain is established,and the kinetics analysis of the tail is carried out.The corresponding relationship between the motion parameters and the transformation of different maneuvering postures by the spatial tail-swing propulsion model is studied,such as linear cruising,turning,lifting and other postures.2.From the point of view of hydrodynamics,flow field,etc.,the evolution of the flow field of the spatial tail-swing propulsion is discussed,and the wake vortex morphology in the space state is established.The mechanism of the wake vortex flow field on the propulsion performance of the caudal fin is analyzed.The CFD technique is used to numerically simulate the simplified model of the tail-swing in the spatial plane,and the flow field information of the wake vortex is qualitatively analyzed.3.According to the kinematic and mechanical analysis of mathematical motion model,a suitable driving mode is chosen to design the spatial tail-swing propulsion mechanism and design motion control system of the tail-swing propulsion system,and the gravityadjustment mechanism is designed for the instability of the center of gravity in the process of the spatial tail-swing propulsion.On this basis,the experimental prototype of the propulsion system is made completely.The experimental research on the bionic tail-swing propulsion device with crescent fin is carried out to provide persuasive and convincing support for the spatial hydrodynamics model and biomechanical analysis by using the freely advancing & swinging experimental platform.