Magnetic bearings consist of magnetic poles arranged in a circular configuration in order to levitate a spinning rotor. Since they are non-contact bearings they reduce losses due to friction. In addition, since they are an active control device, they offer excellent opportunities for vibration control. Currently, high costs and technological limits have prevented their widespread use.

They represent a challenging problem to a dynamicist since a proper design involves a melding of electromagnetic theory, electronics, control systems and rotor dynamics. We have been working on several aspects of magnetic bearings and have also managed to build one with a grant from ONR. Some of the work that has been carried out (or is ongoing) is listed below.

•   Nonlinear analysis of magnetic bearings
•   Optimal design of magnetic bearings
•   Heat transfer in an electromagnetic bearing
•   Experimental investigation of magnetic bearings
•   Analytical derivation of dynamic coefficients for magnetic bearings (yet to be published)
•   Compensation for support motion using magnetic bearings which resulted in some publications:
  •   Compensation of base motion in magnetic-bearing supported rotors for Navy applications
  •   An Optimal Control Algorithm for Suppression Of Harmonic Base Excitation In Nonlinear Magnetic Bearings
  •   A Combined PD and Optimal Control of a Nonlinear Magnetic Bearing Rotor Subject to Harmonic Base Motion
  •   Suppression Of Base Excitation Of Rotors On Magnetic Bearings
•   Bifurcation analysis in magnetic bearing supported rotors
•   Optimal design of EM bearings with PM bias (currently funded by ONR)