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.

中文翻译：

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基于无网格局部Petrov-Galerkin方法的流体-结构相互作用用于蠕虫软机器人分析

本研究的目的是使用结构和流体的无网格局部Petrov-Galerkin（MLPG）方法开发一种双向流体-结构相互作用（FSI）方法，以准确预测蠕虫软机器人的非线性行为。先前对软机器人的研究主要是通过有限元分析（FEA）进行的。但是，即使在FEA中采用自适应网格时，软机器人的非线性行为也会导致元素变形和相邻元素之间的不连续应力。因此，此处使用MLPG来精确预测软机器人的非线性行为，而无需使用有限元。另外，气动软机器人仿真需要双向FSI分析，该分析可以按顺序在流体和结构之间以及结构和流体之间发送和接收数据。为了提高界面的准确性，此处采用了任意的拉格朗日-欧拉方法和水平集方法。验证了有限元法FSI和已开发的MLPG FSI方法的最大误差分别为4.69％和0.77％，并且后者方法所需的节点少于FEM。