On the dynamics of the vibration-driven multipole magnetoactive bristlebot

摘要

Abstract Recent advancements in soft robotics have led to the development of various mobile robots incorporating smart materials such as magnetoactive elastomers. This work presents a modeling and solution framework to analyze the motion behavior of a multipole magnetoactive bristlebot actuated by the alternating magnetic field of an integrated electromagnetic coil. A rigid-body model with two degrees of freedom is proposed as a simplified representation of the bristlebot. The model is subjected to harmonic excitation through a vertical magnetic force, while asymmetric dry friction forces from the inclined bristles resist the motion. The theoretical analysis is based on the principles of vibrational mechanics, enabling the separation of coupled dynamics into the fast vibrating motion and the slow uniform linear motion. The numerical solution reveals that the linear velocity depends in a resonant manner on the excitation frequency and primarily on the ratio of the friction coefficients rather than their absolute values. An analytical expression is derived for the maximum velocity achievable under magnetic excitation, independent of the surface on which the model moves. A design recommendation for the optimal bristle inclination angle is provided based solely on the length ratio of the model’s rods. Comparison with experimental data measured for the bristlebot confirms that the proposed rigid-body model, despite its minimal set of parameters, qualitatively captures the resonant dependence of the linear velocity on the excitation frequency. These findings offer valuable guidance for the design and optimization of bristle-based mobile robots.