Vibration Control and Unbalance Estimation of a Nonlinear Rotor System Using Disturbance Observer

Abstract

In rotating machinery, rotor unbalance causes many resonances at critical speeds corresponding to different modes. In this paper, a vibration control method for rotor systems utilizing disturbance observer is proposed. The nonlinear terms, unbalance, parameter variations, and uncertain terms of a rotor system are lumped into a disturbance term, and this term is canceled by using disturbance observer. As a result, the vibrations are suppressed to small amplitudes all over the rotational speed range. Simultaneously, unbalance of the first mode is estimated from the information of control force of disturbance observer. Moreover, the effects of parameter errors of the control system are also investigated. The validity of the proposed method is verified through numerical simulations and experiments.