Horizontal spin of ratchet motor by vertical agitation

Toshinobu Takahashi,Erika Okita,Akihisa Shioi,Daigo Yamamoto,Yasunao Okamoto

doi:10.1038/s41598-021-91319-8

Toshinobu Takahashi, Erika Okita + Show 3 more

Open Access

https://doi.org/10.1038/s41598-021-91319-8

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Abstract

The horizontal spin of a ratchet motor by vertical vibration is reported. A macroscopic ratchet gear is placed on a granular bed, where nearly half of the gear is penetrated in the bed. The gear and granular bed are mechanically vibrated. The gear shows a random motion or one-way spin that depend on the diameter of the granules, vibration frequency, and degree of vertical motion allowed for the gear. Even when one-way spin is observed, the spin direction depends on the abovementioned factors. Although the dependency is complicated, it is deterministic because the motion or flows of granular matter determines it. The characteristics observed in the experiments are explained by a simple model that accounts for the statistical variance in the motion of the granular matter. Extraction of systematic motion from small and non-useful motions such as mechanical agitation will be developed into energy harvest technology and may facilitate the science of a spontaneously moving system in a uniform potential field.

Highlights

The horizontal spin of a ratchet motor by vertical vibration is reported
Random motions caused by nonequilibrium processes such as chemical reactions and mechanical agitations can be transformed into systematic m otions[3,4,5,6,7]
The uniform thermal motion under thermal equilibrium is meaningless from the technological perspective, whereas a similar motion under nonequilibrium state is useful for generating a systematic motion

Summary

Introduction

The horizontal spin of a ratchet motor by vertical vibration is reported. A macroscopic ratchet gear is placed on a granular bed, where nearly half of the gear is penetrated in the bed. (Supplementary Movie 1, for symmetric and asymmetric gears.) For all experiments in the present study, the symmetric gear exhibited random motions, where the spinning direction changed many times occasionally, as shown, where the angular velocity of the symmetric gear fluctuated around zero. This indicates that the gear motion randomized with an increase in the bead diameter, and that the angular velocity was the maximum at a diameter of approximately 0.6 mm.

Results

Conclusion