title: Control of Magnetic Bearings for Rotor Unbalance With Plug-In Time-Varying Resonators.
abstract: Rotor unbalance, common phenomenon of rotational systems, manifests itself as a periodic disturbance synchronized with the rotor's angular velocity. In active magnetic bearing (AMB) systems, feedback control is required to stabilize the open-loop unstable electromagnetic levitation. Further, feedback action can be added to suppress the repeatable runout but maintain closed-loop stability. In this paper, a plug-in time-varying resonator is designed by inverting cascaded notch filters. This formulation allows flexibility in designing the internal model for appropriate disturbance rejection. The plug-in structure ensures that stability can be maintained for varying rotor speeds. Experimental results of an AMB-rotor system are presented.
authors.affiliation: Mechatronics and Controls Laboratory, Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, Los Angeles, CA 90095 e-mail:  chriskang@g.ucla.edu.
authors.forename: Christopher
authors.initials: C
authors.lastname: Kang
authors.affiliation: Professor Mechatronics and Controls Laboratory, Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, Los Angeles, CA 90095 e-mail:  ttsao@seas.ucla.edu.
authors.forename: Tsu-Chin
authors.initials: TC
authors.lastname: Tsao