Active air rotary bearing (1st report) - Principle of the AARB and identification of dynamic parameters

The aim of this research is to develop the air rotary bearing which has the following capability: (1) compensation of motion errors of the axis (high accuracy), (2) reduction of motion errors and residual vibrations which external disturbances cause (high stiffness and high vibration damping), (3) control of five degrees of freedom axis motion of the rotating axis (new function). To realize these, the authors propose an `Active Air Rotary Bearing' #(AARB). The AARB comprises an axis, two active air journal bearings which consist of four non-contact actuators and two non-contact sensors and an active air thrust bearing which consists of a non-contact actuator and a non-contact sensor. The AARB can support and drive the axis using the non-contact actuators. This paper describes the principle of the AARB and the identification of dynamic parameters. The models used for the identification are simple and the frequency responses of dynamic models agree well with those of an experimental mechanism.