A Sea‐Anemones‐Inspired 3‐DOF Rotary Piezoelectric Actuator with Compact Structure and Microradian‐Scale Resolution

Abstract Sea anemones can perform flexible hunting movements through the bending of their tentacles and contraction of their body walls. Inspired by these unique movements, this paper presents a piezoelectric actuator capable of achieving three degrees of freedom in rotary motion. The actuator mimics the motion of sea anemones through various vibration modes in a thin‐walled circular ring. The structure is compact with dimensions of Φ56 mm × 8 mm and a total weight of 26 g, and consists of a metal substrate and two circular‐ring four‐quadrant piezoelectric ceramics. Contraction and bending modes, similar to those of sea anemones, can be induced by applying voltages to the piezoelectric ceramics. Three degrees of freedom motions can be achieved by combining these two modes. The actuator exhibits high speeds (≈317/300/163 rpm) and precise micro‐displacements (≈14/11/24 µrad). Experimental validation includes tests on the movement of a flexible printed circuit and image acquisition in confined spaces, demonstrating the actuator's potential for applications in defect detection in flexible electronic devices and field‐of‐view scanning. This work demonstrates that using mode superposition methods to mimic biological motion can achieve high‐performance, multi‐degree‐of‐freedom driving capabilities. This work provides new design insights for actuators applied in advanced robotics and electronics.