Center for Interdisciplinary Biosciences, Technology and Innovation Park, P. J. Šafárik University in Košice, Jesenná 5, 041 54 Košice, Slovak Republic.
Department of Biophysics, Faculty of Science, P. J. Šafárik University in Košice, Jesenná 5, 041 54 Košice, Slovak Republic.
Phys Rev E. 2023 Feb;107(2-1):024603. doi: 10.1103/PhysRevE.107.024603.
This study aims to examine experimental conditions in which active particles are forced by their surroundings to move forward and backward in a continuous oscillatory manner. The experimental design is based on using a vibrating self-propelled toyrobot called hexbug, which is placed inside a narrow channel closed on one end by a rigid moving wall. Using the end-wall velocity as a controlling factor, the main forward mode of the hexbug movement can be turned to mostly rearward mode. We investigate the bouncing hexbug motion on both experimental and theoretical grounds. The Brownian model of active particles with inertia is employed in the theoretical framework. The model itself uses a pulsed Langevin equation in order to simulate abrupt changes in velocity that mimic hexbug propulsion in the moments when its legs make contact with the base plate. Significant directional asymmetry is caused by the legs bending backward. We demonstrate that the simulation successfully reproduces the experimental characteristics of hexbug motion after regressing the spatial and temporal statistical characteristics, especially when directional asymmetry is under consideration.
本研究旨在考察在实验条件下，活性粒子在其周围环境的作用下，以连续的振荡方式向前和向后移动。实验设计基于使用一种称为 Hexbug 的振动自推进玩具机器人，将其放置在一个狭窄的通道内，通道的一端由一个刚性的移动壁封闭。通过控制端壁的速度，可以将 Hexbug 的主要前进模式转换为主要后退模式。我们从实验和理论两方面研究了 Hexbug 的反弹运动。理论框架中采用了具有惯性的活性粒子的布朗模型。该模型本身使用了一个脉冲朗之万方程，以模拟在其腿部与基板接触的瞬间，Hexbug 推进时速度的突然变化。腿部向后弯曲会导致显著的方向不对称性。我们证明，在回归空间和时间统计特性后，特别是在考虑方向不对称性时，模拟可以成功再现 Hexbug 运动的实验特征。
