Model-based nonlinear control of a new active tilting-pad bearing

This paper introduces a new type of active fluid-film bearing and its feedback control. In particular, we propose to actively adjust the angular velocity of the pads of a tilting-pad bearing in response to changes in the operating conditions of the rotating machine. This is motivated by the observation that there is more control authority in the pad tilt motion than in its radial translation. To this end, we first develop a dynamic model for the bearing system, inclusive of the nonlinear hydrodynamic force for the infinitely-short bearing case. A model-based controller is then constructed, based on measurements of the journal position and velocity and pad tilt angles, to ensure that the journal is asymptotically regulated to the bearing center. Numerical simulations illustrate the performance of the active bearing under the proposed control in comparison with the bearing's standard passive mode of operation.