Vibration Control of a Nonlinear Rotor System through Electro-Magnetic Bearings

Abstract

In rotating machinery, vibration resonance with large amplitude and complex pattern occurs at critical speeds due to rotor imbalance and nonlinear effects. In this paper, a vibration control method is proposed for a rotor system supported by a ball bearing and an electro-magnetic bearing. In particular, a disturbance observer combined with the current delay estimation is implemented to improve the controller's ability of compensating for system's nonlinear effects and uncertainty. As a result, the rotor vibration is suppressed to very small amplitudes in the entire operating speed range. The proposed method is validated through numerical simulations and experiments.