壓電平台已被廣泛地使用在高解析度的量測儀器系統，其可以達到微米或奈米級別的定位精度。然而壓電平台所使用的致動器是由壓電材料所構成，此材料特性可以對電壓變化量做出形變或對形變量產生電壓，但它具有高度非線性的特徵(如遲滯、耦合等)，進而導致控制上的困難。除此之外，壓電平台的追蹤軌跡設計也是影響最終控制成效的一大關鍵。為了解決上述提到的困難，本篇論文提出了一個複合式的控制架構，由多自由度Bouc-Wen前饋控制器及擴增狀態估測有限時間滑模回授所組成，意在解決非線性及干擾相關的難題，並透過穩定性證明展示其有效性。此外，傳統的柵欄式掃描軌跡設計，其成分包含三角波的訊號源，此訊號容易引起機械系統的高頻共振。有鑑於此，本篇論文提出一種修正式的柵欄式軌跡，將原先的三角波替換為順滑轉換的路徑形式，來避免不必要的高頻訊號產生，藉此減緩高頻共振問題。 最後，透過對系統一系列的模擬與實驗結果進行比較，可展現本論文提出的控制架構及軌跡設計的優異性。 ;The piezoelectric stage is widely used in high-resolution measurement systems for exploring and manipulating the micro-/nano- scales world. The stage’s actuator is made of piezoelectric material, which can deform its shape when a voltage is applied (and vice versa). However, this material suffers from nonlinearities, such as hysteresis and cross-coupling. Besides, the tracking trajectory design affects the overall performance and output image qualities of the AFM system. To overcome the problem, first, we combine a Bouc-Wen feedforward control scheme with an extended state observer-based finite-time dynamics sliding mode feedback control to address these nonlinearities. Second, we proposed a modified raster trajectory that replaces a sharp turning point with a smooth-out transition to minimize the unwanted high-frequency oscillation phenomenon as much as possible. A series of simulation and experimental results were compared to demonstrate the performance of the proposed trajectory and control method.
