Dynamic analysis and optimization of soft robotic fish using fluid-structural coupling method

Aiming to design a soft robotic fish with more natural, more flexible and high-performance movements through biomimetic method, we are developing a soft robotic fish with body/caudal fin (BCF) propulsion by using piezoelectric fiber composite (PFC) as actuator. Compared with conventional rigid robotic fish, the design and control of the soft robotic fish are difficult and hard to reveal its dynamic performances due to the large deformation of flexible structure and complicated coupling dynamics with fluid. That´s why the design and control method of the soft robotic fish has not been established, and we need to study it by considering the interaction between flexible structure and fluid. In this paper, fluid-structural coupling analysis based on acoustics method is applied to consider the fluid effect and predict the dynamic responses of soft robotic fish using PFC in fluid. Basic driving and governing equations of soft robotic fish in the fluid are firstly described. Then the numerical acoustics coupling analysis is performed. The calculated results are congruent well with experiments on dynamic responses. Finally, based on this coupling method, a new prototype of soft robotic fish is proposed by optimization for improvement.