Precision stage using a non-contact planar actuator based on magnetic suspension technology

Abstract

The precision stage using a novel contact-free planar actuator based on magnetic forces, magnetized force and Lorentz force, is suggested. In the promising magnetic structure, a mover is levitated by magnetized force between iron-core electromagnets attached under the upper-side of a stator and ferromagnetic plates belonging to the mover. And the mover is driven by Lorentz force that acts on permanent magnets with an identical polarity put under magnetic field by air-core coils. Namely, the mover is driven directly without any transmission mechanism, and does not need any auxiliary driver for its posture calibration. Then it is estimated that the proposed operating principle is very suitable for work requiring high accuracy and cleanness, or general-purpose nano-stage. In this paper, we discuss a driving principle of the planar system including the magnetic force generation mechanism, a framework for the force model, governing characteristics of the levitated plate, and a planar motion control of the constructed prototype. And experimental results are given to verify the derived theoretical model and the feasibility of the system.