Fluid-Structure Interaction Based on Meshless Local Petrov-Galerkin Method for Worm Soft Robot Analysis

Abstract

The purpose of this study was to develop a two-way fluid-structure interaction (FSI) method using the meshless local Petrov-Galerkin (MLPG) method for both the structure and the fluid to accurately predict the nonlinear behavior of a worm soft robot. Previous research on soft robots has been mainly performed by finite element analysis (FEA). However, the nonlinear behavior of a soft robot causes element distortion and discontinuous stress between the adjacent elements, even when adaptive mesh is employed in the FEA. Therefore, MLPG was employed here to precisely predict the nonlinear behavior of a soft robot without using finite elements. In addition, a pneumatic soft robot simulation requires two-way FSI analysis that can transmit and receive data between the fluid and the structure, and the structure and the fluid, in sequence. To improve accuracy for the interface, the arbitrary Lagrangian-Eulerian method and the level set method were applied here. It was verified that the maximum errors of the finite element method FSI and the developed MLPG FSI method were 4.69%, and 0.77%, respectively, and the latter method required fewer nodes than FEM.