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ABSTRACT: Modern manufacturing equipment often requires high-speed and ultra-precise linear motion. For implementing such motion, a
coarse–fine dual stage is effective because the coarse stage has a low bandwidth with a large workspace, and in contrast,
the fine stage has a high bandwidth with a small stroke. This paper presents the implementation of an air-bearing, dual-stage
system and its control strategy. A closed-loop feedback in an absolute space is used to realize coarse–fine control. The fine
stage is driven by a voice coil motor that tracks the designed trajectory, while the coarse stage is driven by permanent-magnet
linear synchronous motor that tracks the trajectory of the fine stage to prevent its motion saturation. Also analyzed are
the coupled dynamics of the air-bearing dual stage driven by a direct-drive motor. Identification and robust control design
for the fine stage are introduced in detail. Method tests for the single fine stage are performed, and the results demonstrate
that ultra-precision control can be realized for the fine stage. Next, experiments are presented with the dual stage using
different loads. Experimental results show that our control strategy can achieve high-speed, ultra-precision linear motion
through the dual stage with a satisfactory performance.
KeywordsControl system-Linear motion platform-Coarse–fine control-Model identification
International Journal of Advanced Manufacturing Technology 04/2012; 48(5):633-643. · 1.10 Impact Factor
