干擾觀測器於週期時變系統 - 動態增益觀測方法

Abstract

在工業與工程議題中，精密動態系統若受到外部干擾會嚴重影響其性能表現，因此本論文提出一個可應用在所有週期時變系統之干擾觀測方法。首先透過提昇取樣（lifting technique）將週期時變系統轉換成非時變系統，接著利用干擾觀測器同時對此系統狀態和外部未知干擾進行線上估測。此干擾觀測器之結構可使得干擾觀測問題類比為干擾抑制控制問題，並藉此利用標準 H_infinity 控制設計方法達成干擾觀測器之系統化設計，此外，其另一項優點在於可適用於極小相位系統及非極小相位系統。

In engineering and industrial applications, disturbances acting on a dynamic system present a serious problem to system performance. This thesis will focus on the disturbance estimation for periodically time-varying systems. Lifting technique is first used to transform the periodically time-varying system into a time invariant system. A new disturbance observer is then proposed for the lifted system to simultaneously estimate both the system state and external disturbances. A unique feature of the new disturbance observer is that there exists a analogy between the proposed disturbance observer design problem and the disturbance rejection control design problem. As a result, the proposed disturbance observer can be designed in the frequency domain using standard H_infinity control design techniques. Another advantage of the proposed disturbance observer is that it can be applied to both minimum-phase and non-minimum-phase systems.