Abstract
Flexible rotors supported by Active Magnetic Bearings (AMBs) are subject to the ISO 14839-3 concerning the evaluation of stability margin. In this study, we prepared PID AMB controllers in conjunction with several filters : notch filter (NF), phase bump filter (PBF) and phase shifting filter (PSF). Our AMB system is controlled by mode regulators : parallel mode and tilting mode. According to the ISO instruction, we measured the sensitivity function and evaluated the stability margins by the peak values. In our test, the combination of PSF for parallel mode and NF for tilting mode best meets the ISO standard. Corresponding to these test results, we developed a simulation method to calculate the sensitivity function. This rigid-bending combined model involves a mass matrix obtained by mode synthesis and a stiffness matrix tuned by anti-resonance frequencies of measured plant transfer function data. Consequently, the precise prediction of the sensitivity peak is completed by this modeling.
