The Mechanism And Experimental Research Of Bionic Dolphin’s Tail Swing Based On Rudder Drive

With the development of science and technology,land resources are no longer able to meet the needs of mankind,and marine resources have become the focus of development in various countries.Most of the existing underwater vehicles have shortcomings such as low efficiency,slow speed and short endurance.After long-term evolution,fish have fully adapted to the underwater living conditions,so the research of bionic robotic fish has become a hot spot in various countries,and dolphins have more prominent swimming ability,so the research on robotic dolphins is even more crucial important.The focus and difficulty of the research on the bionic robotic dolphin is the study of the tail swing mechanism.The first problem to be solved in the study of the mechanism of the robotic dolphin’s tail swing is the driving method of the bionic dolphin’s tail.This article summarizes the advantages and disadvantages of different driving methods of bionic robotic fish at home and abroad,and finally chooses the steering gear as the driving method of the bionic dolphin tail to study the swing mechanism of the dolphin’s tail.In order to solve the shortcoming of the excessive rigidity of the bionic dolphin tail joint caused by the steering gear drive,this paper uses the steering gear drive plus the flexible spine to solve the problem,and then studies it through theoretical analysis,simulation analysis and experimental research methods The tail swing mechanism of a bionic dolphin.The specific work completed in this paper is as follows:This paper analyzes the tail swing mechanism of the bionic dolphin in the state of direct swimming and jumping.Firstly,the energy replacement method is used to explore the influence of the frequency,amplitude and phase difference of the tail swing of the bionic dolphin on the speed of the dolphin in the state of direct swimming.The kinematics nonlinear characteristic equation of the dolphin’s tail swing is given;then,the tail swing mechanism of the dolphin is analyzed under the condition of jumping.Through the force analysis of the propulsion stage,inertia stage and water entering stage of the dolphin in the jumping process,we get The minimum water speed required by the dolphin under different body lengths and water exit angles is calculated;then the tail attack angle,tail joint angle and tail joint power of the dolphin are calculated;finally the control model CPG control model of the dolphin tail swing is established,And conducted a simulation analysis on it.The experimental prototype of the bionic dolphin was developed.First,the design idea of the bionic dolphin experimental prototype was determined as the modular design idea.Then the bionic dolphin experimental prototype is divided into head module,body module and tail module.The head module has two degrees of freedom and can cooperate with the tail swing for jumping and turning;the body module mainly includes the pectoral fin swing mechanism,the center of gravity adjustment mechanism,and the body shell;the tail module uses three servos in series to form the dolphin tail Swing mechanism,in order to solve the rigidity problem caused by the driving of the steering gear,two flexible spine columns are added to the tail swing mechanism in this design,thereby adding six driven joints,and three active joints form the tail of the dolphin.Nine-joint swing mechanism;finally,the control system of the dolphin is designed and the data monitoring interface of the upper computer is compiled.The kinematics and dynamics simulations of the designed bionic dolphin are carried out.First,the kinematics model of the dolphin tail swing mechanism is established,and the kinematics simulation is performed on it using Matlab,thereby verifying that the designed nine-joint bionic dolphin tail swing mechanism has better A good fish body wave fitting curve;then the dynamic modeling is carried out to obtain the swimming speed value of the bionic dolphin under different phase difference,swing amplitude and frequency.Finally,the kinematics and dynamics modeling and simulation of the dolphin tail fin are carried out to analyze the best phase difference when the tail fin swings.Equipped with an experimental prototype,through fish body wave curve comparison experiment,underwater cruise experiment and tail fin swing experiment,further research on the swing mechanism of the bionic dolphin’s tail is carried out.