摘要
氣壓致動系統具有簡單、乾淨、便宜、容易裝備與維護、一般性操作安全、高能量密度等優點，因此廣泛地運用於工業界之程序機械作業。但由於傳動媒體的可壓縮性、閥流之非線性特性與系統不連續時變摩擦效應等高度非線性特性，致使氣壓致動器較少見用於工業伺服作動。為解決此一問題，除了硬體系統與元件之研發與改良外，較複雜之非線性控制器設計如強健控制、適應控制、與智慧型控制等策略之運用，也促使氣壓伺服控制技術得以有所進展。
在時變負載氣壓伺服系統模型之建構上，可發現系統數學模型包含了未匹配不確定項。既然與控制訊號不在同一途徑或範圍空間，其不確定項之動態行為或許將造成閉迴路系統之不穩定。為解決此一問題，本文審慎地找尋系統各參數之邊界，在忽略部分參數影響下，採用多層滑動控制策略控管這些未匹配不確定項，而達到精密致動之目的。
當考慮邊界未知與未建模之系統參數時，可發現系統模型之時變特性使得傳統適應性控制之設計並不適用。為克服估測這些不確定參數可能造成之奇異解問題，本文首先提出一非奇異解調整器之設計，而以函數近似技術為基礎之適應性多層滑動控制器使系統在參數皆為未知之狀況下達到精密致動之效果。
為突破氣壓伺服系統對壓力量測的依賴性，傳統解決方法是採用觀察器，但其結果除了系統階數增加外，還會產生不必要的奇異點。因此本文另闢蹊徑，針對氣壓伺服系統的動態方程式進行重新安排，經由適當地參數轉換使得壓力感測器之訊號回饋得以被省略。此新建模之系統，可藉由適應性多層滑動控制器之設計以確保系統的穩定性，而所提設計的效能則可藉由實驗來加以印證。

Abstract
Pneumatic actuators have widely been used in manufacturing and process industries due to their various advantages such as clean in nature, cheap, simple and easily maintained, generally safe in operation, and good power density. But for their inherent highly nonlinear properties such as compressibility of medium, friction effect and nonlinearity of valves, pneumatic actuators are seldom used in industrial servo applications. To cope with the problems, some advanced pneumatic servo mechanisms and elements are developed and investigated. In addition, the major impetus to the development of pneumatic servo control technology arrived with emergence of complex nonlinear controllers design such as robust, adaptive, and intelligent approaches though the possible low cost computing.
The mathematical model of a pneumatic servo system with time-varying payload is typically characterized by a high-order non-autonomous dynamics with mismatched uncertainties. Since these uncertainties are not in the range space of the control effort, they may enter into the system dynamics to destabilize the close loop system. To deal with the problems, this dissertation proposes a multiple-surface sliding controller (MSSC) design though identifying explicit parameters restrictions to take care of the mismatched uncertainties. With the robust control, an accurate positioning is achieved.
In order to cope with the possible singular problem coming from the time-varying uncertainties estimating, we proposed a tunable regulator design to have a better improvement. Under the nonsingular estimation, this dissertation proposed a function approximation technology (FAT) based adaptive MSSC design to stabilize the accurate positioning pneumatic servo system with bound unknown uncertainties.
To reduce the demand for precise modeling of the pneumatic servo system, some researchers used state observers instead of expensive pressure sensors. However, increasing of the system order and possible singular points further complicated the design and implementation. In this dissertation, a transformation is suggested to reformulate the dynamic equation such that the pressure sensor feedbacks can be neglected. A FAT based adaptive MSSC is designed to stabilize the system. Experiments are conducted to demonstrate the effectiveness of the proposed designs.

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