Normal vibration induces tangential friction in an arch-shaped tribological robot

Dynamic control of friction is fundamental to achieving adaptive locomotion in robotic systems. Inspired by biological seta-like structures, we present a symmetrical arch-shaped robot capable of bidirectional tangential motion driven by normal vibrational excitation. By exploiting the interplay between structural self-deformation, friction forces, and vibrational excitation (frequency and amplitude), we demonstrate how directional motion emerges from friction asymmetry between the robot's two feet. A theoretical model is developed, and numerical experiments are performed to investigate the impact of friction coefficient, normal excitation frequency, and amplitude on tangential movement. The results indicate that the friction forces may display periodic patterns and result in bidirectional motion at varying excitation frequencies and amplitudes. This work establishes a framework for friction-driven robots, offering insights into bioinspired strategies for tunable tribological control with potential applications in adaptive systems.