Design And Hydrodynamics Analysis Of Biomimetic Robotic Fish Based On Three Degree Freedom Pectoral Fins

In recent years,with the development of science and technology,the study about robot fish becomes a studying hot spot in bionic scientific research field.The research on underwater robots in the bionic field is based on the vigorous development of different science and technology disciplines related to the bionic field,such as the mechanics of the design institutions,the bionics of the fish body shape,the hydrodynamics of the fish swims in fluids and other technical disciplines,it have gradually shown important research significance in the research of underwater robotics.In this paper,based on the propulsion mode and swimming mechanism of the bionic robotic fish,a pectoral fin propulsion mechanism with three degrees of freedom and a bionic robotic fish model with a three-joint flexible body are designed,and the corresponding hydrodynamic model for the designed bionic robotic fish were established.On this basis,the corresponding three-degrees of freedom pectoral fin biomimetic robotic fish was subjected to the corresponding hydrodynamic analysis,and finally verified through experiments.Specific content as follows:(1)Bionic objects with cod,designed a three-degree-of-freedom pectoral fins and three-joint flexible caudal fins synergistic propulsion bionic robot fish;Each bionic pectoral fin propulsive mechanism includes a bionic pectoral fin,the feathering mechanism,the flapping mechanism,and the rowing mechanism.The biomimetic robot fish pectoral fin propulsion mechanism can realize the independent motion corresponding to each of the three servos,and can realize the complex compound motion between the two and the three.(2)In the condition that the pectoral fins are each given degrees according to a given sine motion rule,and the flexible body is moved by a body wave fitting method,the pectoral fin rowing motion,the feathering motion,the flapping motion,and the composite motion between the three are performed respectively.Hydrodynamic analysis was performed by using the microelement method and a hydrodynamic model for the linear swimming of the designed bionic robotic fish was established.Through numerical analysis and experimental analysis,the speed of pectoral fins for a single degree of freedom of the prototype was0.038m/s,the two-degree-of-freedom pectoral fins travel speed is 0.13m/s,and the three-degree-of-freedom pectoral fins travel speed is 0.17m/s.From the above,it can be concluded that as the number of degrees of freedom increases,the direct speed of the prototype also increases,reflecting the effectiveness of the pectoral fin with three degrees of freedom.(3)In the condition that the pectoral fins are each given degrees according to a given sine motion rule,and the flexible body is moved by a body wave fitting method,for the one side pectoral fins to driven the turn,the pectoral fins and the caudal fins were coordinated todriven the turn,and the bilateral pectoral fins were used to driven the turn and the corresponding hydrodynamic analysis was performed and the hydrodynamic model of the bionic robot fish swimming was established.Through numerical analysis and experimental analysis,the experimental results of the prototype under different turning modes were obtained,and the effectiveness of various movement forms of the bionic robotic fish was finally obtained.