Parameter Identification for S tiffness and Damping in AMB-Flexible Rotor System

To describe the support characteristic of an Active Magnetic Bearing(AMB) in rotor system via the traditional rotor dynamic theory, the equivalent stiffness and the equivalent damping are the frequently-used and important parameters. Some methods have been proposed for measuring the support parameters of AMB. However, most of them were based on the single degree of freedom(DOF) model or the multi-DOF rigid rotor model. In this study, a measuring method is proposed to identify the equivalent stiffness and the equivalent damping of the rotor radial support, which is employed in the flexible rotor system levitated on AMB. By means of the condensation of DOF in finite element rotor model, which includes the static force equivalence or the dynamic force equivalence, the whole rotor DOFs can be reduced to some certain DOFs and the number of the unknowns in the condensed model is decreased. The relation between the excitation and the response is extracted from the condensed rotor model. The identification equations are established in condition of the AMB excitation. By numerical simulation, the parameters of the equivalent stiffness and the equivalent damping of the AMB support are effectively identified and the possible problems are analyzed.