多軸壓電平台的電荷迴授遲滯干擾觀測器設計

Charge Feedback Hysteresis Disturbance Observer Design of a Multi-axis Piezo-actuated Stage

溫盛帆(Sheng-Fan Wen)

指導教授 ： 顏家鈺

國立臺灣大學/工學院/機械工程學研究所/碩士(2014年)

https://doi.org/10.6342/NTU.2014.00495

摘要

壓電致動器驅動的平台具有良好的動態響應及極高的解析度，被廣泛應用於微奈米行程的精密定位系統，卻因為輸入電壓與位移之間有遲滯、潛變等非線性現象，無法以單純的線性非時變系統表述，造成控制上的困難。
本論文將遲滯視為一個對線性系統的干擾，並提出一種利用流經壓電致動器的電荷量來即時補償遲滯干擾的控制架構。儲存於壓電致動器電荷被一串接於壓電致動器的電容所量取，通過Preisach模型計算出遲滯干擾，然後補償於控制輸入之中。在此架構之下，遲滯造成的非線性現象被此觀測器所補償，數位控制器只需針對壓電致動器所推動的線性的機械系統作控制設計，可以大幅簡化控制演算法的複雜度。相較於常見的反遲滯模型架構，本方法較強韌且易於實現；相較於利用電荷迴授或電荷放大器來做壓電平台的控制，本方法既不需要設計複雜的電荷放大器電路，也較無頻寬上的限制。壓電致動器的模型與分析、參數識別、Preisach模型的建構流程、平台的動態響應分析等都包含於本論文之中。本論文亦加入低通濾波器、前饋補償器來進一步提升控制成效。不同頻率下的追蹤控制以及反覆來回的階梯型的追蹤控制結果呈現本方法能夠有效地消除遲滯干擾。

關鍵字

壓電致動器 ； 電荷迴授 ； 干擾觀測器 ； 遲滯模型 ； 精密運動控制

並列摘要

Piezo-actuated stage has excellent dynamic response and high resolution, and is widely used in micro- or nanoscale precision positioning systems. However, the nonlinearities such as hysteresis and creep make its control very difficult.
In this thesis, the hysteresis nonlinearity is considered as an extra disturbance over a linear system. A novel approach using the parasitic capacitance charge feedback in conjunction with a Preisach model to estimate the hysteresis disturbance is proposed. The charge over the parasite capacitance is measured through a serially connected capacitance. The hysteresis disturbance is calculated on-line using the Preisach model and is added to the control input. Under this architecture, the hysteresis nonlinearity is compensated by the hysteresis observer and the digital controller deals only with the linear electro-mechanical system. The setup dramatically reduces the complexity of controller design. In contrast to the inverse-model-based control, this approach is more robust and easier to implement. The proposed approach requires no complex charge amplifier circuit and has little limitations on the bandwidth. The thesis provides detailed analysis and parameter identification of the piezo actuator, the building process of the Preisach model, and the dynamic response analysis of the stage. Low pass filter and feed forward compensator are also employed to improve the tracking performance. Tracking control results under sinusoidal reference at different frequencies and stair-case reference tracking confirms the effectiveness of this approach.

並列關鍵字

Piezoelectric actuators ； charge feedback ； disturbance observer ； Preisach model ； precision motion control

參考文獻

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