Simulation-Based Controller Design for an Active Auxiliary Bearing

A framework for the development of a feedback controller for an active auxiliary bearing is presented. In a new approach, a dry bushing type auxiliary bearing is attached to the foundation via two unidirectional actuators. The control force is applied indirectly using the active auxiliary bearing only in case of rubbing. A simulation for the elastic rotor and the auxiliary bearing including the non-smooth nonlinear dynamics of the rubbing contact is used to develop the feedback controller. A robust two-phase control strategy has been developed which stabilizes the rotor system in case of rubbing and effectively avoids “backward whirling”. Experimental studies have been carried out at a rotor test rig. The experiments show the outstanding success of the strategy. In case of rubbing, the contact forces are reduced up to 85%.