使用回授做控制設計的時候，有兩個必須注意的問題：（一）增加迴饋控制的增益裕度，提升系統的容錯率。（二）降低雜訊所造成的誤差，雜訊是無可避免的，而雜訊會對整個系統的控制有著不良的影響。上述的問題，在使用二次線性最佳化計算控制器之後，有了初步的改善效果。本論文對於輸出回授最佳化設計提出了更進一步的改良方法，首先，利用證明提出藉由內隱模式的安置，可以降低輸出回授最佳化設計中的控制器增益，再透過數值實驗的方法，找出內隱模式最適合的安置位置，使得設計出來的控制器，可以針對各個不同的系統，更有效地增加回饋控制的增益邊限，提升系統的容錯率，或是會對雜訊有更好的抵抗力，以降低雜訊對閉迴路系統的影響，讓輸出回授最佳化控制的設計更為良善。

There are two major fields could be improved by the design of the output feedback control. One is the increasing gain margin of the feedback control and the other is the suppressing error of the system noise. Noise, which is usually an unavoidable problem in all control systems. In order to eliminate the harmful effect of noise, this thesis proposes the output feedback linear quadratic method for optimizing the output feedback system design. First, proposing the controller gain in the output feedback linear quadratic can be eliminated by locating the hidden mode is an effective method with proves. Second, finding the best location in the hidden mode by the mathematical experiments in order to increase the gain margin and robustness in the output feedback control. Moreover, obtaining a better noise resistivity for the closed-loop control system and deriving a better performance for the output feedback linear quadratic control system.

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