Robust self-propulsion in sand using simply controlled vibrating cubes

TL;DR

This paper introduces a simple vibratory cube robot that can robustly move across granular terrains by self-vibration, offering a new locomotion method that outperforms traditional wheeled or legged robots on such surfaces.

Contribution

The study demonstrates a novel vibratory locomotion mechanism using a cube-shaped robot with embedded vibratory motors, effective on various granular terrains, and explores its potential for modular robotic systems.

Findings

Vibratory locomotion enables faster movement on granular media.

The mechanism provides more stable movement compared to hard surfaces.

Cube robots can be modular for complex maneuvering tasks.

Abstract

Much of the Earth and many surfaces of extraterrestrial bodies are composed of in-cohesive particle matter. Locomoting on granular terrain is challenging for common robotic devices, either wheeled or legged. In this work, we discover a robust alternative locomotion mechanism on granular media -- generating movement via self-vibration. To demonstrate the effectiveness of this locomotion mechanism, we develop a cube-shaped robot with an embedded vibratory motor and conduct systematic experiments on diverse granular terrains of various particle properties. We investigate how locomotion changes as a function of vibration frequency/intensity on granular terrains. Compared to hard surfaces, we find such a vibratory locomotion mechanism enables the robot to move faster, and more stable on granular surfaces, facilitated by the interaction between the body and surrounding granules. The simplicity in structural design and controls of this robotic system indicates that vibratory locomotion can be a valuable alternative way to produce robust locomotion on granular terrains. We further demonstrate that such cube-shape robots can be used as modular units for morphologically structured vibratory robots with capabilities of maneuverable forward and turning motions, showing potential practical scenarios for robotic systems.