A Theoretical and Numerical Development of the Concept of the Active Control Foil Bearing (ACFB)

The authors of the present paper envisage far reaching applications of the foil bearing technology when merged with the concept of active control. Thus, this paper proposes and presents a comprehensive procedure for feedback control design for an active foil bearing. Two types of controllers are introduced, and discussed: i) the active feedback control for online adjustment, and ii) the supervisory control for anticipatory event management. A numerical procedure to simulate the steady state and transient dynamics of a foil bearing was also presented.Successful introduction of such a new type of bearing will allow: (a) tolerance and ‘on-line’ adaptation to large time-dependent distortions and misalignment, (b) continuous adjustment for enhanced stability and resilience to high speed rubs, (c) reduced wear and power loss, (d) relative immunity from foreign object damage (FOD), (e) high load capacity due to thicker film lubricant, (f) lighter weight and reduced spatial envelope over active magnetic bearings, and (g) inherent stability without feedback control as compared with the magnetic bearing which has no stable equilibrium without feedback.Copyright © 1995 by ASME