Asymmetric gear rectifies random robot motion

¹ Department of Physics and Institute of Natural Sciences, Shanghai Jiao Tong University Shanghai, 200240, China

^(a) hepeng_zhang@sjtu.edu.cn

Received: 17 March 2013
Accepted: 24 May 2013

Abstract

We experimentally study the dynamics of centimetric robots and their interactions with rotary gears through inelastic collisions. Under the impacts of self-propelled robots, a gear with symmetric teeth diffuses with no preferred direction of motion. An asymmetric gear, however, rectifies random motion of nearby robots which, in return, exert a torque on the gear and drive it into unidirectional motion. Rectification efficiency increases with the degree of gear asymmetry. Our work demonstrates that asymmetric environments can be used to rectify and extract energy from random motion of macroscopic self-propelled particles.