Abstract
This paper presents a new modeling method and a control system design procedure for a flexible rotor with many elastic mode using active magnetic bearings (AMBs). The purpose of our research is to rotate the rotor for passing through critical speeds caused by flexible modes. In this report, design and development of local feedback controller for each AMB is dealt with. Jerk Feedback Controller is adopted and its system design taking account of elastic vibration of the rotor is discussed. To enhance so-called servo stiffness, a phase-lag compensator is added onto the local feedback controller. Levitation experiment using the presented local controller is carried out and stable levitation with sufficient damping effect is achieved. Consequently rotating experiment is performed. Rigid body vibration modes of the rotor are arisen and the local feedback controller could not suppress them because it is designed as SISO controller for each AMB. MIMO feedback controllers including all AMBs are needed. For that purpose, Extended-Reduced Order Physical Modeling procedure (EROM) is introduced to obtain whole AMB-rotor model. Computer simulations are carried out to confirm the property of the obtained model.
