A 3 DOF model for an electro magnetic air mount

Abstract

A 4 × 4 matrix model with three degrees of freedom is proposed as a means for controlling microvibrations and applied to an electromagnetic isolator. The model was derived from an assumption based on small-and low-frequency vibrations. The coordinates of the 3 DOF was composed of the 4 variables, representing a vertical position, pitch, roll, and a proof term. The coordinates were calculated from the 4 position sensors in the isolator and formulated into a 4 × 4 matrix, which possesses inversive full rank. The electro-magnetic isolator was built for a simulated machine in semiconductor manufacturing and consisted of a heavy surface plate, sensors, amps, a controller, and air springs with electromagnets. The electromagnets are installed in a pneumatic chamber of the individual air spring. The performance of the 3 DOF model was experimented and compared with that of a 1 DOF model in an impact test. The settling time in the result was reduced to 25%.

A Hybrid Structure of Dual Stators and a Pneumatic Spring for Resonance Control in an Air Mount

“…netic forces, we have developed two kinds of active devices. An internal type contains the electromagnetic parts in an air chamber of the air spring [9]. A permanent magnet moves in the vertical direction, and is connected to an upper plate, which contacts a surface plate.…”