Research On Soft Robotic Fish Based On Hydraulic Fishtail Drive With Cavity Structure

Soft robotic fish play an important role in underwater detection.Compared to traditional underwater vehicles with the rigid shell and propeller drive,soft robotic fish have the flexible body and bionic propulsion mode which bring the advantages of low disturbance and high adaptability.To realize the flexible imitation of organisms,soft drives have been widely used in the research of soft robot fish.With the continuous innovation of materials,various soft driving methods have been created and introduced into the design and production of soft robotic fish.However,in most of the existing soft robotic fish,researchers made a partially flexible body of the robotic fish instead of a fully flexible one;and the robotic fish with fully flexible body still need an external device for driving.There is still no report on the research on the overall flexible soft robot fish that can move autonomously.To solve the contradiction between full flexibility and autonomy in the design of small soft robot fish,this paper adopts fluid drive as the main driving method of soft robot fish,and research on the mechanical fish system design,the theoretical analysis and simulation of the deformation mechanism of the cavity structure fluid fish tail drive,the production and experiment of bionic prototype.In this paper,the theoretical research and simulation analysis of the cavity structure fluid fishtail drive was carried out.A simplified straight cavity model was used to describe the deformation mechanism of the cavity structure fishtail drive,which have shown that the bending angle of the cavity structure drive is proportional to the pressure in the cavity.The kinematics analysis of the straight cavity structure drive was carried out with the piecewise constant curvature method.The simulation method was used to further reveal the deformation mechanism of pleated cavity and double cavity fishtail.To meet the design requirements of full flexibility,miniaturization and autonomous movement of soft robotic fish,a design method of soft robotic fish based on cavity structure hydraulic fishtail drive was proposed.In this paper,the special structural design of the drive and balance design were carried out and the design of the control system was completed.In this paper,a soft robotic fish prototype was manufactured by using silicone casting and splicing technology to realize the independent swimming of the softmolded fish prototype.In the fish tail experiment,the applicability of the straight cavity structure theoretical analysis method in the pleated cavity structure was verified,and the deformation mechanism of the fish tail was further analyzed.In the experiment of the soft robotic fish,the effect of the frequency and swing of the cavity structure hydraulic fishtail drive on the thrust of the whole fish in the running state was studied,which shows that the fish tail frequency determines the propulsion compared with the swing.