Research On Rigid-flexible Integrated Bionic Robotic Fish Driven By Flexibility

In recent years,in order to improve the performance of robots in liquid environments,there has been a growing interest in mimicking the direction of nature.This is mainly due to the greater prospects of bionic technology compared to conventional propeller drive technology.Current biomimetic technologies designed to enable fish swimming have similar characteristics,with the continuous body fluctuations required using redundant manipulator rib-shaped spines.Therefore,the motion mechanism,driving mode and system structure of the bionic robot fish driven by flexible drive are studied.Firstly,the propulsion mode and driving mechanism of the bionic robot fish are studied,and the driving mode and swimming mode of the bionic robot fish are determined.Based on the morphological analysis of fish,the overall design of biomimetic robotic fish was carried out.The tail model of ribbed cavity structure is proposed,and the complex motion of the flexible driving fish body is realized by the working principle of fluid drive scheme and hydraulic drive pump for compliance and continuity.Secondly,based on the BCF(body and/or tail fin propulsion)mode of fish body kinematics and swimming kinetic analysis,the deformation mechanism of flexible tail drivers is analyzed,and a mathematical model of fish tail deflection angle is constructed.ANSYS software was used to simulate and analyze the bending performance of the ribbed cavity fishtail 3D model,and the change of bending angle under different situations of load application in the numerical simulation was compared with the calculation results of the mathematical model to verify the correctness of the fishtail configuration.Thirdly,the constitutive model of the hyperelastomer material is established,and the three-dimensional model of the fish body is hydrodynamic analysis by using FLUENT,and the hydrodynamic characteristics of the fish body are analyzed according to the flow field pressure cloud and vortex diagram at different times.The simulation of pectoral fin in the flow field at different angles of attack was carried out,the lift and resistance under different angles of attack,and the corresponding changes of lift and drag coefficients were analyzed,and the influence of pectoral fin angle of attack on the hydrodynamic performance of fish was analyzed.Finally,according to the ribbed cavity structure in this paper,a mold that can realize the integrated molding of the model is designed.The manufacturing method of silicone casting and lost wax process is used to complete the production of ribbed cavity flexible fishtail,and build a bionic robot fish system that realizes continuous motion rigid-flex integration through flexible fishtail drive.The bending test under different pressures was carried out to verify the effectiveness of the flexible drive and the correctness of the fishtail mathematical model and simulation analysis.