Bristlebots as active matter
Bristlebots are vibration-driven robots, characterized by the overlay of fast inner vibration and the translocation of the overall system. An asymmetry in the system characteristics is required for the transformation of the internal periodic excitation to a direction locomotion, e.g., bristles can mechanically interlock with a surface and provide asymmetric friction forces.
Bristlebots of different designs got popular in recent years and became commercially available, e.g., the ‘Hexbug Nano’. The directed motion, boundary control, and emergent properties of an ensemble of these self-propelled robots, serve as a wonderful analogy to the properties of active matter systems. Namely, the active Brownian motion of Janus particles, run-and-tumble dynamics of E-coli bacteria baths, and even flocking behavior in groups of animals.