Abstract: The backward phenomenon of the stick-slip piezoelectric actuator seriously affects its positioning accuracy and motion stability. The existing suppression methods, which mostly rely on mechanical structure optimization or closed-loop control, still have certain limitations. This study addresses the issue of backward motion from the perspective of interfacial tribology and proposes a biomimetic flexible friction pair for a stick-slip actuator. Inspired by the anisotropy of the microstructure of reed leaves, the surface morphology was replicated using PDMS, and a flexible biomimetic friction pair was fabricated through plasma treatment. By adjusting the orientation of the microstructures on the driving foot relative to those on the slider surface, four types of anisotropic friction pairs were constructed. The experimental results indicate that biomimetic anisotropic friction pairs are effective in suppressing backward motion, and that specific flexible friction pairs can eliminate the backward phenomenon without increasing mechanical or control complexity. Through microscopic morphology characterization and contact theory analysis, the friction enhancement mechanisms and microscopic mechanical mechanisms of different biomimetic microstructure combinations were revealed. This actuator combines high performance, compact structure and simple control, and is particularly suitable for precision micro-robots, space operations and optical positioning, which have strict requirements for volume, energy consumption and reliability.

Key words: Bionic microstructure')">Bionic microstructure, Bionic friction surface, Piezoelectric actuator, Bionic flexible friction pair, Bionic friction mechanism