|
JING Minqing
LI Zixin
LUO Min
YU Lie
College of Mechanical Engineering,
Xi’an Jiaotong University,
Xi’an 710049, China |
|
|
UNBALANCE RESPONSE AND
TOUCH-RUBBING THRESHOLD
SPEED OF ROTOR SUBJECTED
TO NONLINEAR MAGNETIC
FORCES
Abstract:
Because of the effect of unbalance excitation and nonlinear magnetic force, the large vibration of the rotor supported by active magnetic bearing(AMB) will go beyond the radial gap of the bearing, even causing mechanical touch-rubbing when the system works at an operational speed closer to the critical speed. In order to investigate this problem, the linear model and nonlinear model of the single mass symmetric rigid rotor system supported by AMB are established respectively and the corresponding transfer functions of close-loop system are given. To pass through the numerical calculation by using MATLAB/Simulink, the effect of both the unbalance response and threshold speed of touch-rubbing of the system subjected to nonlinear magnetic forces and nonlinear output current of power amplifier are studied. Furthermore, threshold speed of touch-rubbing of the rotor-bearing system is defined and the results of numerical simulation are presented. Finally, based on above studies, two methods of increasing the touch-rubbing threshold speed are discussed.
Key words:
Active magnetic bearing (AMB) Vibration Non-linearity Touch-rubbing speed |
|
|
Biographical notes
JING Minqing is currently an associate professor in College of
Mechanical Engineering, Xi’an Jiaotong University, China. He received
his PhD degree from College of Mechanical Engineering, Xi’an Jiaotong
University, China, in 2004. His research interests include active
magnetic bearing technique, monit- oring and diagnosis, application
technique of digital signal processing, etc.
Tel: +86-29-82669149; E-mail: mjing@mail.xjtu.edu.cn
LI Zixin is a professor. His research interests include rotor dynamics,
mechatronics.
LUO Min is a BS candidate. His research interests include mechatronics,
active magnetic bearings.
YU Lie is a professor. His research interests include tribology,
vibration control, rotor dynamics, mechatronics, active magnetic
bearings and fault diagnosis and condition monitoring.
References
[1] DURALI M, BATENI H. Nonlinear behavior and control of active
electromagnetic bearings[J]. International Journal of Modeling and
Simulation, 1999, 19(4): 397-404.
[2] CHIACCHIARINI H G, MANDOLESI P S. Unbalanced compensation for active
magnetic bearings using ILC[C]//IEEE Conference on Control Applications
- Proceedings, Mexico, Sep. 5-7, 2001: 58-63.
[3] LIU Shuqin, SU Xuecheng. Robust PID controller design for active
magnetic bearing[C]//Seventh International Symp. on Magnetic Bearings,
ETH Zurich, August 23-25, 2000: 305-310.
[4] JI J C, LEUNG A Y T. Nonlinear behavior of a magnetically supported
rotor[C]//Seventh International Symp. on Magnetic Bearings, ETH Zurich,
August 23-25, 2000: 23-28.
[5] PUST L. Weak and strong nonlinearities in magnetic bearings[J].
Mechanism and Machine Theory, 2004, 39(7): 779-795.
[6] HE Qinxiang, LIU Ying. The nonlinear dynamic behavior analysis of
magnetic levitated rotor-bearing system[J]. Chinese Journal of Applied
Mechanics, 2004, 21(3): 113-116. (in Chinese)
[7] LIU Zhansheng, LU Jian, LÜ Weijian, et al. Dynamic behavior of a
rotor magnetic bearing (RMB) system with the fault of rub between rotor
and stator[J]. Journal of Aerospace Power, 2004, 19(1): 38-44. (in
Chinese)
[8] WANG Yuefang, HUANG Lihua, LI Yong. Nonlinear vibration and
stability of a Jeffcott rotor under unbalanced magnetic excitation[J].
International Journal of Nonlinear Sciences and Numerical Simulation,
2007, 8(3): 375-384.
|