Design And Research Of A Novel Flexible Bail Propellant Bionic Fish

Traditional underwater thrusters have the disadvantages of low efficiency,poor flexibility,and large noise.Bionic fish is a new type of underwater propulsion device that draws on the characteristics of swimming of real fish.Many traditional underwater thrusters are incomparable.The advantages of this project have broad application prospects in marine resources development,search and rescue exploration,and military affairs.More and more scholars have devoted themselves to the research of biomimetic fish and have made a series of important achievements.Fish movement is very complicated.Currently,researchers use multi-joint series and parallel structures to simulate their movements.This device design reduces the mechanical transmission efficiency and adopts a “one-tailed” approach to achieve fish motility mode.The change also increases the complexity of the swimming control of the bionic fish and reduces the flexibility of swimming.In order to solve the above problems,this topic discusses a bionic fish underwater propulsion device with a flexible fishtail.The flexible body has many degrees of freedom.A single flexible unit can better realize a complex simulation of fish swimming.A single excitation is applied to the flexible fish tail,the input energy is stored by the inertia and elasticity thereof and is dissipated by the viscous,and achieves high swimming efficiency near the resonance frequency.Different from the commonly-used "one-tailed multi-use" scheme,this topic proposes a scheme for separately controlling the underwater movement of the bionic fish and the turning motion.This increases the flexibility of the mobile modal changes and reduces the complexity of the control.The main research work is as follows:(1)Analyze the fish swimming mechanism and summarize and analyze the fish swimming methods.According to the knowledge of fluid mechanics,the propulsive force produced by the BCF propulsion fish during its swinging process was analyzed.It provides a reference for the design of the fish body structure and the design of the drive device for the biomimetic fish.(2)The carp carp was selected as the bionic object,and the three-dimensional model of the bionic fish and the flexible caudal fin were designed based on the structural parameters of each part of the carp fish body.Based on the principle of magnetic effect of current and knowledge of mechanical design,a bionic fish drive device,a transmission structure and a mode switching device of a swimming mode are designed.To achieve the control of the direction and direction of the bionic fish.(3)The software and hardware control system based on X281 XDSP is designed,and the on-line control of the swim of the bionic fish is realized through the LabVIEW communication upper computer based on the VISA serial port.The target tracking system was used to obtain the trajectory curve of the bionic fish,and the image data was measured using the image processing method.Finally,this paper analyzes the experimental structure of the bionic fish and explores the relationship between the swimming speed of the bionic fish and the swing parameters of the flexible fishtail.When the other parameters are constant,the quadratic curve relationship between the speed of the swimming and the tail fin oscillation frequency is obtained.The feasibility of the proposed method for changing the swimming modality of the bionic fish was verified.The turning radius of the bionic fish designed by this project is mainly affected by two factors,namely the frequency of tail fin oscillation and the angular acceleration of mass rotation in the fish body.The influence of two factors was analyzed separately,and the parameter values of the two influencing factors can be adjusted to achieve the required turning radius.