針對具有未知擾動之線性系統，基於觀測器所建構之改良型強健伺服控制設計在本論文中被提出。首先，針對具有未知擾動之線性連續時域極小相位系統，其整合狀態估測器與未知輸入干擾估測器之誤差動態系統的特徵值，被以最佳化的方式移置在具有特定相對穩定度之s-平面的某線左側。類似的優點亦被應用於伺服機制設計，因此，文獻上受限於必須是低頻的未知干擾才得以被估測暨必須是變化緩慢的時變指令輸入訊號才得以達到伺服機制控制等限制，得以被放寬至估測更為廣泛的高頻未知干擾與追蹤劇烈變化的指令輸入訊號。對照於上述之優點，連續時域版本的設計方式同時被推廣至針對具有極小相位或非極小相位之離散時域版本的設計。特別是，針對具有未知干擾之離散系統，一種基於當下輸出資訊所建構的新型狀態估測器/未知輸入干擾估測器在本論文中被提出。此外，基於等效輸入干擾準則，所提方法亦可適用於非匹配輸入干擾。

Improved robust observer-based servo designs are proposed in this thesis for the linear systems subject to unknown disturbances. First, the poles of the error dynamic system of the state observer integrated with the unknown input estimator for the continuous-time minimum phase system subject to unknown input disturbance (UID) are optimally assigned to lie to the left of some vertical line in the s-plane with prescribed degree of relative stability. Similar merit has been also applied to the servo design. Consequently, restrictions on the estimation of UID with low frequencies and servo control for slow time-varying command inputs presented in literature have been released to the cases for the UID with high frequencies and drastic time-varying command inputs, so that a more wide range unknown input estimations and servo designs can be achieved. In contrast with the above-mentioned merits, the proposed approach for the continuous-time systems has been also extended to the discrete-time version for the minimum phase and/or non-minimum phase systems. Especially, the new current-output observer/UID esitmator-based servo design for the discrete-time system with an unknown disturbance is proposed. Furthermore, based on the equivalent input disturbance (EID) principle, the proposed approaches are applicable to the class of mismatched input disturbances.

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