Non-Linear Finite Element Analysis of Biologically Inspired Robotic Fin Actuated by Soft Actuators

Abstract

In this paper, a robotic fin was idealized with three rays, which are serially connected by thin flexible rubber membranes. Each ray consists a two chamber braided soft actuator operated by pneumatic pressure at the maximum of 20 kPa. The bending of the ray is achieved by alternating the supply of air to the chamber. The soft actuator bends to the right when the left chamber is pressurized and moves to the left when the right chamber is pressurized. The propulsive wave motion along the fin is thus achieved by oscillating the rays at the same frequency but in different phases. The finite element (FE) analysis was conducted in MARC ® , nonlinear FE software, from which the lateral displacements of the rays and the corresponding effect on the membranes were measured. The wave amplitude of the fin was computed from the simulation results. The wave motion of the robotic fin and its corresponding pressure distributions were also observed and presented.