Comparison and Classification of High-Precision Actuators Based on Stiffness Influencing Vibration Isolation

Positioning performance of high-precision systems is influenced by vibrations transmitting from floors and types of the precision actuators. To construct a compact actuator with high vibration isolation for these systems, this paper investigates and categorizes precision actuators based on their stiffness for providing design rules. The effectiveness of the analysis and the design rules is confirmed by experiments comparing two types of compact precision actuators: piezoelectric and electromagnetic (Lorentz or voice coil) actuators. The positioning system with these actuators is validated experimentally by applying step-like disturbances of approximately 160 nm to the base of the actuators. While the position error of the piezo-actuated system swings by about ±200 nm, the Lorentz-actuated system that satisfies the design rules is able to suppress the error within a range of ±10 nm.