Numerical and experimental study on the novel active aerostatic bearings with the controllable throttling effect for obtaining high static stiffness

Active compensation is an effective method to improve static and dynamic performances of aerostatic bearings. However, the limited compensation bandwidth limits the development and application of active compensation methods in aerostatic bearings. This study presents the novel active aerostatic bearings based on active flow resistance compensation, which adopts the voice coil motor as an actuator to change the throttling area of the restrictor to control the throttling effect. Computational Fluid Dynamics (CFD) is used to study the pressure distribution, flow field characteristics, and static characteristics of passive and active bearings. The numerical results of both bearings are compared and show that the vortices and the stiffness of active bearings are suppressed and increased, respectively. The stiffness of active bearings can always be maintained at maximum by controlling the voice coil motor motion when the air film thickness is varied. Three experimental test-beds are designed to examine the performance of active bearings. The numerical and experimental results of load capacity are compared and obtained in good agreement. Moreover, the tested micro-vibration validates the characteristics of vortices. Coupling the numerical and experimental results proves the controllability of active bearings, which means that active bearings can adapt to different operating conditions and maintain optimum performance by controlling the throttling effect.