Design, Control of an Aerostatic X-Y Planar Motion Stage for Precision Positioning

Recently the manufacturing industry has seen increasing demand for micro-components in biomedical, opto-mechatronics, and automotive applications. In particular, a positioning table system combining high accuracy with high speed over large travel ranges. However, the traditional stage constructed by stacking one-axis stages to achieve multiple degrees of freedom motion, are no longer a viable solution to meet the tighter tolerances required by the customers. In order to meet these demands simultaneously, the paper proposes an aerostatic X-Y planar motion stage featuring high resolution (80nm), long stroke, non-contact moving, lightweight and compact structure. It employs a slider consisting of four three-phase coils, which can move along the surface of a standard hal bach permanent magnetic array in a non-contact condition due to being elevated with air bearing. Furthermore, control system is designed including feedback and feed forward controllers. To further improve the tracking performance and eliminating recurrent disturbances, iterative learning control is employed. Performance evaluation results show that the developed planar motion stage can realize a remarkable performance which includes fast settling time and micrometer positioning with high speed over large ranges.