A multiphysics model for optimizing the design of active aerostatic thrust bearings

Aerostatic bearing solutions avoid problems related to friction and enable high precision linear guiding. However, their relatively low stiffness hinders the accuracy when disturbance forces, such as inertial effects or machining forces, are present. An active compensation strategy based on air gap shape control with piezoelectric actuators has been proposed, which can achieve nanometre position control and high bandwidth disturbance compensation. Suitable design strategies and tools still need to be developed to optimize the performance and enforce the industrial application of these systems. This paper proposes a new multiphysics finite element model which considers the interaction between the air flow dynamics, the structural flexibility of the bearing, the piezoelectricity for the actuators and the control with strongly coupled formulation. A setup for high bandwidth and resolution experiments has been built and used to test the prototypes. The experimental results prove the validity of the model and the relevance of the fluid-structure interaction, and thus the need for such a coupled multiphysics model for optimizing the design of active air bearings. (C) 2010 Elsevier Inc. All rights reserved.