High-Precision XY Stage Motion Control of Industrial Microscope

This paper presents an economic way to implement a high-precision (micrometer level) XY stage motion control for the industrial microscope using dc motors. Other than the prevailing design of using stepper motors where the stage is always locked under the motorized mode, the proposed design allows users to manually move the stage by introducing the friction engagement in between. The non-linearity from the friction is then fully compensated by the sliding mode control so that the stage can strictly follow the predefined motion profile. Possible chattering suppression methods are discussed and the accuracy loss is analyzed using the LuGre friction model. A fine-tuning algorithm is then proposed to limit the position error within +/- 2 mu m. Compared to the other micrometer-level industrial microscopes using stepper motors, the proposed solution achieves comparable performance with much lower costs.