Structural design and dynamic analysis of robotic fish with piezoelectric fiber composite

Robotic fishes using artificial muscle as actuators have been described recently. The purpose of this work is to develop a flexible robotic fish using the piezoelectric fiber composite (PFC). To achieve the good flexibility and mobility of the robotic fish, we proposed a simple and compact structure. The load simulation method of piezoelectric actuator was employed to improve the fish's movement performance and swimming efficiency. By the analysis of the driving characteristics of the PFC, the robot structure with symmetrical distribution was designed based on the caudal fin propulsion mode. This structure was verified reasonable in the theoretical and simulation method. The dynamic characteristics of this underwater robot were both analyzed through the experiments and numerical analysis of Finite Element Method (FEM). The calculated results were congruent well with the experiment measurements of the prototype. Relatively high swimming speed was achieved during the experimental tests for a prototype. This indicated the numerical methods can be applied in the structural optimization and dynamic analysis of the robotic fish. More information will be available for the fluid-structure interaction analysis in future.