A piezoelectric inertial actuator operating with elliptical drive and stick-slip drive modes

This study improves the performance of piezoelectric inertial actuators by merging the benefits of inertial and inchworm drives and proposes a flexible actuator that utilizes elliptical drive mode (EDM) and stick-slip drive mode (SDM). Employing four piezoelectric stacks as the excitation source, the actuator transforms vertical motion into lateral motion through leaf-type flexible beams. The structure design, assembly, and drive principles of the proposed actuator are presented in detail, and its flexible stator structure is optimized using the finite element method. A dynamic model is established to analyze the step characteristics under both operational modes. The actuator prototype achieves a maximum velocity of 2.89 mm/s and eliminates backward motion at 90 Hz frequencies. The EDM mode shows improved load capacity, while the SDM mode provides faster speeds, indicating different performance characteristics depending on the drive methods. Ultimately, we successfully applied the proposed actuator in semiconductor inspection, demonstrating its application potential. This design surpasses current piezoelectric inertial actuators in speed, load, and resolution, facilitating performance optimization without structural alterations to accommodate diverse application requirements. This research offers valuable insights into optimizing actuator performance, with potential applications in high-precision scanning and optical system tracking for atomic force microscopy.