On line identification of unbalance parameters and active control in a rotor bearing system

In this paper an algebraic technique for unbalance parameters identification along with an active control scheme for a rotor bearing system are presented. The system has two disks asymmetrically located along the shaft which is supported by a conventional ball bearing at one end and by an active suspension at the other one. The active suspension is based on linear springs and linear force actuators in order to provide the control force for vibration attenuation. A reduced order system model is obtained using Finite Element Method (FEM). The identification process is carried out on line and the only required measurements are the lateral shaft displacements at the disks location. FEM model and identified unbalance parameters are used to synthesize an active control scheme in order to attenuate the lateral vibration amplitudes in the rotor bearing system. Numerical results show the robust performance of the algebraic identification technique and considerable reductions in vibration amplitudes when the system passes through its first critical speed.