System Identification and Calibration Techniques for Force Measurement in Active Magnetic Bearings

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dc.contributor.authorPrins, Robert Jacken
dc.contributor.committeechairKasarda, Mary E. F.en
dc.contributor.committeememberLeo, Donalden
dc.contributor.committeememberKirk, R. Gordonen
dc.contributor.committeememberHall, Christopher D.en
dc.contributor.committeememberInman, Daniel J.en
dc.contributor.departmentMechanical Engineeringen
dc.date.accessioned2014-03-14T20:20:45Zen
dc.date.adate2006-01-05en
dc.date.available2014-03-14T20:20:45Zen
dc.date.issued2005-12-08en
dc.date.rdate2009-01-05en
dc.date.sdate2005-12-16en
dc.description.abstractMany processes involving rotating machinery could benefit from the continuous feedback of force applied to the bearings that support the machinery. Such a system could be used to provide diagnostics for process monitoring in a manufacturing application or to provide information for machine health monitoring. Active Magnetic Bearings (AMBs) have the capability to act concurrently as a shaft force sensor and support bearing. This capability stems from the AMB's control system, which is designed to maintain a specific rotor position, regardless of forces acting on the rotor. Researchers have demonstrated the force sensing ability of AMBs; current state of the art methods typically rely on a direct measurement of magnetic flux density as provided by a Hall probe inserted in the magnetic field. In this work, a system identification approach to force measurement is proposed; the proposed approach is applicable to all active magnetic bearings and does not require Hall probes. Recent developments in system identification of bearing forces (Kasarda et al., 2000) indicate that a different approach is feasible. In the work of Marshall (Marshall et al., 2001), a variety of perturbations are applied to an AMB while the AMB controller signals are interrogated, no outside instrumentation such as force transducers or Hall probes are required. The work of Kasarda and Marshall is the starting point for the work presented here. The initial work was expanded to include a general characterization of air gap for any rotor position. Although this characterization relies on static testing to identify system parameters, the identified parameters can then be used in the measurement of dynamic forces. The identification procedure provides a measurement of effective air gap length. Effective gap length is used to infer the effective position of the rotor with respect to the stator. This measurement is made for several specific rotor locations. The relationship between the effective rotor positions provided by the identification and the rotor positions reported by the AMB system sensors establishes a coordinate transformation. The procedure is also applied at different shaft rotation angles. In this way rotor runout can be identified.en
dc.description.degreePh. D.en
dc.identifier.otheretd-12162005-093328en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-12162005-093328/en
dc.identifier.urihttp://hdl.handle.net/10919/30117en
dc.publisherVirginia Techen
dc.relation.haspartPrins_dissertation.rev2.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectForce Measurementen
dc.subjectIdentificationen
dc.subjectMagnetic Bearingsen
dc.titleSystem Identification and Calibration Techniques for Force Measurement in Active Magnetic Bearingsen
dc.typeDissertationen
thesis.degree.disciplineMechanical Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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