Design Concept and Structural Configuration of Magnetic Levitation Stage with Z-Assist System

Abstract

Magnetic levitation technology is expected to provide a solution for achieving nanometer-scale positioning accuracy. However, magnetic leakage limits the application of the magnetic levitation stage. To reduce magnetic density, motors should be installed at an appropriate distance from the table. This increases the axis interference between the horizontal thrust and the pitching, making it difficult to achieve stable levitation. In this study, a magnetic levitation stage system that has a unique motor structure fusing a gravity compensation function and pitching moment compensation is proposed. This compensation mechanism operates automatically using the passive magnetic circuit structure, ensuring that noises from the coil current and the timing gaps do not affect the driving characteristics and that neither wiring nor sensors are required. The basic characteristics were evaluated through the driving experiments, and the efficiency of the proposed gravity and pitching moment compensation system was demonstrated.