The bundling of flagella is known to create a "run" phase, where the bacteria moves in a nearly straight line rather than making changes in direction. Historically, mechanical explanations for the bundling phenomenon intrigued many researchers, and significant advances were made in physical models and experimental methods. Contributing to the field of research, we present a bacteria-inspired centimeter-scale soft robotic hardware platform and a computational framework for a physically plausible simulation model of the multi-flagellated robot under low Reynolds number (~0.1). The fluid-structure interaction simulation couples the Discrete Elastic Rods algorithm with the method of Regularized Stokeslet Segments. Contact between two flagella is handled by a penalty-based method. We present a comparison between our experimental and simulation results and verify that the simulation tool can capture the essential physics of this problem. Preliminary findings on robustness to buckling provided by the bundling phenomenon and the efficiency of a multi-flagellated soft robot are compared with the single-flagellated counterparts. Observations were made on the coupling between geometry and elasticity, which manifests itself in the propulsion of the robot by nonlinear dependency on the rotational speed of the flagella.

翻译：摘要：已知鞭毛成束会形成“奔跑”阶段，在此阶段细菌沿近乎直线移动而非改变方向。历史上，成束现象的力学解释曾引起众多研究者的兴趣，并在物理模型与实验方法方面取得了显著进展。为促进该领域研究，我们提出了一个厘米级仿细菌软体硬件平台，以及针对低雷诺数（~0.1）下多鞭毛机器人物理合理模拟模型的计算框架。流固耦合模拟将离散弹性杆算法与正则化斯托克斯流段方法相结合。两根鞭毛之间的接触通过罚函数方法处理。我们展示了实验与模拟结果的比较，并验证了模拟工具能够捕捉该问题的基本物理特性。初步发现表明，与单鞭毛对应物相比，成束现象提供的抗屈曲鲁棒性以及多鞭毛软体机器人的效率均更优。观察到了几何与弹性之间的耦合关系，这通过鞭毛转速的非线性依赖性体现在机器人的推进过程中。