Frictional anisotropy of ant legs and related inspired 3D-printed textured surfaces with self-locomotion on ultrasound vibrating substrates

Micro-spike textures in ant's leg were investigated using Atomic Force Microscopy and frictional anisotropy was explored. Bio-inspired textured surfaces were 3D-printed with different material properties and orientation. Fundamental tribological test was carried out to evaluate static and dynamic frictional behavior of printed textures. Results showed frictional anisotropy; forward sliding friction was lower compared with backward direction, similar to ant's leg. Uni-directional driving speed was evaluated under ultrasonic vibration. Ant and all textured samples showed driving capability. 3D-printed sample with a maximum speed of ∼165 mm/s was the stiffer one (Vero-Black) with optimum orientation (65°). Texture sample and plate contact interface was analyzed for driving mechanism using high-speed camera. Material properties, structural mechanics, and friction significantly affect locomotive speed.