Integration and Application of a Long-Stroke Precision Positioning Stage to Micro Fabrication by Two-Photon Polymerization
Date Issued
2015
Date
2015
Author(s)
Chen, Yi-Yi
Abstract
This thesis proposes a long-stroke precision positioning stage, which combines two piezoelectric stages and a stepper motor stage to achieve long-stroke and high-precision positioning. We further apply the combined stage to two-photon polymerization for micro-manufacturing, and propose two performance indices to adjust the designed controllers for further improvement. Precision positioning is becoming prevalent and widely used in many areas, such as atomic force microscopy (AFM), scanning electron microscope (SEM) and nano-manufacturing. Piezoelectric-transducer (PZT) materials are the most commonly used actuators in precision positioning due to their high-driven forces, fast responses and high resolution. However, nonlinearities of PZT, such as hysteresis and creep, might degrade system performance. Furthermore, the physical limits of piezoelectric materials might constraint the moving ranges of PZT. To solve these problems, we linearize our PZT model to obtain transfer functions and consider the nonlinearity of PZT as model uncertainties. We then apply robust loop-shaping technique to design controllers which can guarantee system stability and improve system performance. As for the problem of limited stroke, we combined the PZT stage with a stepper motor stage to enlarge the working rang of the system. We propose a double-loop control structure for system integration, and design an anti-locking function to prevent PZT from reaching saturation dead zones. We then apply the combined stage to two-photon polymerization for micro-manufacturing. We further verify the coordinate of fabricated structure by studying different control sensor layouts. Finally, we propose two performance indices: the first is image processing of the SEM results; The second is optical quality of images by the fabricated micro-lens. Based on these indices, we can adjust the designed controllers for further improvement by two-photon polymerization.
Subjects
robust control
piezoelectric-transducer
nano-positioning
long-stroke precision positioning
two-photon polymerization
system integration
Type
thesis
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