在本篇研究中，本文將針對非線性系統來設計一個可追蹤參考輸入之H∞-非線性控制器，足以應付某些非線性動力系統中含有未知參數(Unknown Parameter)或系統內部改變的不確定性(Uncertainty)。在此加入非線性控制器後，所形成之非線性閉迴路系統將其化為標準的Lure結構系統，將利用多變數圓穩定準則(Multivariable Circle Criterion)來分析此非線性系統的穩定性，並探討不確定非線性項之可容許範圍。
文中更加探討H∞/LTR的設計過程。透過修改 狀態觀察器(State Observer)的參數，使得H∞輸出回授控制器(Output Feedback Controller)能夠逼近到預先設計的目標迴授迴路( Target Feedback Loop)。如此H 輸出回授控制器將具有預先設計的性能，並驗證H∞/LTR理論對各種雜訊的強健性。
文中為驗證H∞-控制器理論之推導，依以上之理論程序，以電腦模擬將H∞/LTR設計方法所得到的H∞-控制增益和觀察增益代回原來的非線性系統中，來檢驗是否達到設計性能;並當系統具有非線性不確項在可容許的範圍內，系統依然滿足絕對穩定。

In this thesis, a nonlinear H∞/LTR control law, which is capable of tracking desired reference inputs and matching prescribed specifications, is developed. To cope with some nonlinear dynamic systems which include both unknown parameters and uncertainties, the system dynamics are formulated first into the so-called the standard H∞-control problem so that the H∞-optimal control law and H∞ transfer recovery technique (H∞/LTR) can be applied to ensure the closed-loop stability while rejecting the system uncertainties. Then, the nonlinear closed-loop dynamics can be formulated into the form of the Lure-type problem so as to assure the closed-loop stability under sector-bounded uncertainties.

Before discussing the H∞/LTR design procedure, we have to modify the parameters of H∞ state observer to match the desired target feedback loop obtained from the prescribed specifications of the system. The robustness property of the proposed H∞/LTR methodologies will be attested while the system encounters various disturbances.

To verify the proposed nonlinear H∞/LTR controller, two examples, containing various uncertainties, are used to attest the feasibility of the proposed design methodology.

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