| Summary: | 碩士 === 國立虎尾科技大學 === 電機工程研究所 === 95 === The purpose of the proposed approach is to design a tracking controller for a piezoelectric actuated five degree-of-freedom coplanar nanostage which can provide high-precision applications. The nanostage allows displacements parallel to the sample surface (x-y plane) and perpendicular (z-axis) to the sample surface and the corresponding angles to x θ (x-axis) and y θ (y-axis). It can be applied to an atomic force nanomeasuring machine stage. The hysteresis effects and creep effects are the piezoelectric actuated platform provided nonlinear behavior, this study propose an inversion approach is constructed to numerically describe the hysteresis, creep and coupling effects of piezoelectric actuators. First, a viscoelastic creep model, it was modeled as a series connection of springs and dampers to describe the creep effect. Next, on the basis of the Preisach model, a feed-forward controller is developed to compensate for the hysteresis nonlinearity. A PI controller is introduced to suppress the tracking error due to the modeling inaccuracy and hence to get precision tracking control. The axes motion control problem for the piezoelectric actuated platform is also investigated. A Taguchi method based cross-coupling control scheme is proposed to eliminate the contour error which is typical in dual-axes tracking control problem. The developed approaches are numerically and experimentally verified which demonstrate performance and applicability of the proposed designs under a variety of operating conditions.
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