Abstract
Active magnetic bearings (AMBs) have limited dynamic load capacity due to magnetic saturation. Hence, large external disturbances (such as shock loads) may cause contact between the rotor and touchdown bearings (TDBs), which may evolve into complex dynamic behaviour and damage the machine. This paper considers the shock responses of a rotor and viable re-levitation control options when the AMB is still functional. Bi-stable responses and shock-induced persistent forward rubbing were observed in an experimental AMB-flexible rotor facility and its numerical model. The analytical solution for steady synchronous motions with rubbing of a general AMB-flexible rotor system was proposed. The standard control action for a contact-free rotor state would not be appropriate due to phase changes and the displacement amplitude differences in the frequency responses. To destabilise the persistent contact responses and restore contact-free levitation, open-loop phase search based synchronous compensation (PSSC) control and synchronous motion compensation (SMC) control are designed, which are activated when a persistent contact is detected. Stability of the control system and the effectiveness of these two re-levitation control methods are verified by simulation and experimental results. It is also found by comparison that the efficiency of PSSC depends on the phase difference (incorrect phases may degrade rotor response), while the SMC consumes more computing effort.
| Original language | English |
|---|---|
| Article number | 108174 |
| Number of pages | 22 |
| Journal | Mechanical Systems and Signal Processing |
| Volume | 163 |
| Early online date | 7 Jul 2021 |
| DOIs | |
| Publication status | Published - 15 Jan 2022 |
Bibliographical note
Funding Information:This work was supported by the National Key R & D Program of China (Grant No.2018YFB2000100) and the Tsinghua University Initiative Scientific Research Program (Grant No.20193080086). The authors thank Dr. Runan Zhang and Gauthier Fieux from University of Bath for guiding the use of the instrument.
Funding
This work was supported by the National Key R & D Program of China (Grant No.2018YFB2000100) and the Tsinghua University Initiative Scientific Research Program (Grant No.20193080086). The authors thank Dr. Runan Zhang and Gauthier Fieux from University of Bath for guiding the use of the instrument.
Keywords
- Active magnetic bearing
- Bi-stable phenomenon
- Phase search
- Re-levitation control
- Shock response
ASJC Scopus subject areas
- Control and Systems Engineering
- Signal Processing
- Civil and Structural Engineering
- Aerospace Engineering
- Mechanical Engineering
- Computer Science Applications