Shape optimization for a linear elastic fish robot

Abstract

This paper presents an approach to designing a fish-like linear elastic body whose vibration mode becomes a swimming mode similar to that observed in real fish. To determine the shape of the elastic body, a shape optimization problem is formulated using the squared error norm between the solution of a frequency response and the swimming mode as the cost function and solved by a method based on the $H^1$ gradient method. The body is excited by body forces located at assigned places. The frequency is set around the natural frequency of the eigenmode, mostly in accordance with the swimming mode.