Isotropic optimal controller for rotor bearing systems

Abstract

Increasing demands on rotating machinery in terms of higher running speed, less weight and noise, safety and longevity require well controlled dynamics of the system. This paper addresses a means of actively controlling the synchronous vibrations of a flexible rotor running in flexibly-mounted journal bearings. An isotropic optimal controller of the anisotropic rotor-bearing system in complex state space is designed. The isotropic controller essentially eliminates the backward unbalance response component, leading to circular whirling. Simulation results are presented which demonstrate that the isotropic optimal control is more efficient in controlling unbalance whirl than the conventional optimal control.