Active Air Bearing using Squeeze Film
Generated by Ultrasonic Oscillation
Summary
This study proposes an active air bearing based on squeeze film using ultrasonic actuator. The squeeze film generated by the oscillating actuators lifts and positions actively the floating object. Experimental results showed that the ultrasonic oscillation eliminated residual vibration of the object, and the ultrasonic actuator lifted and positioned the object simultaneously.


This photo is an experimental air bearing using Resonator with Directional Converter.
Axial posisioning and runout compensation have been performed with PI feedback control.
Axial repeatable run-out (RRO) was decreased from 232nm(p-p) to 118 nm(p-p).
Axial nonrepeatabale runout (NRRO) was 30-60 nm (3 sigma).
Radial RRO was decreaded from 1030 nm(p-p) to 957 nm(p-p) .
Radial NRRO was 60-80 nm (3 sigma).

This is an experimental linear rectangular air guideway based on ultrasonic oscillation.
The films on eight bearing surfaces of a horn, which is a stator, lift and guide the carriage. Moreover, the oscillation that modulates the amplitude via the positioning signal varies the thickness of the air film. Thus, this bearing regulates the position of the carriage in z direction using a PI conroller with a displacement sensor sot that its motion error becomes zero.
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