Fig. 1: Description of experimental system and observations.
From: Inertial self-propelled particles in anisotropic environments
a Vibrationally driven self-propelled particle (vibrobot) manufactured by 3D printing. The white cross indicates the particle orientation. Scale bar represents 1 cm. b Experimental setup: Rectangular acrylic baseplate attached to an electromagnetic shaker. The size (width × length) of the top-mounted plate equals 30 cm × 30 cm. c Cross-section of the anisotropic substrate (lenticular foil) with particle to scale. d, e Trajectory density for vibrobots starting parallel (d) and perpendicular (e) to grooves with an excitation amplitude A = 1.28 g. f–h Sketch of the two velocity contributions. The particle moves with increased velocity v∥ when aligned along the grooves (f). When orientated diagonally, the particle moves with average velocity v∥ along its orientation while simultaneously experiencing active propulsion v⊥ perpendicular to it (g). The particle moves with decreased velocity v∥ when perpendicularly aligned to the grooves (h). i–k Three representative trajectories with an excitation amplitude A = 1.60 g. The persistence length is noticeably shorter for perpendicularly aligned particles than for parallel aligned particles. Length ratios and velocity contributions are not to scale.
