應用田口氏方法調整PID控制器

Abstract

摘要

PID控制器在工業領域中依然被廣泛應用，因為它的結構簡單，且有例如Ziegler-Nichols等著名的增益選取法則已經完備的發展。然而，設計PID 控制器使用傳統的Ziegler-Nichols參數選取法則仍面臨某些層面上的困難。首先，它的操作過程中，系統必須運作在臨界穩定以方便量測臨界增益與臨界週期。再者，在高階系統中所獲得之控制器參數將可能產生較大的最大超越量(Maximum overshoot)和較長的安定時間(settling time)。最後，此方法不適用於不穩定的系統。 本篇論文提出了一個新的理念，將Ziegler-Nichols法則與田口氏方法結合。應用田口氏方法不僅可改善系統性能，而且也可對不穩定的系統微調控制器。因此，田口氏方法使得Ziegler-Nichols法則可更加廣泛的應用在大部分的系統。同時，它可讓我們更快速地達到更好的性能指標。 關鍵字：PID控制器，Ziegler-Nichols法則，田口氏方法

Abstract

Proportional-Integral-Derivative (PID) controllers are still widely used in industrial systems. This is mainly because of its simple structure and the existence of the well-known Ziegler-Nichols tuning algorithm. However, applying the classical Ziegler-Nichols PID controller tuning algorithm may face some difficulties. Firstly, the process has to be operated near instability to measure the ultimate gain and period. Secondly, the controller tuned by this method may give larger overshoots and longer settling time for high order system. Thirdly, it can not be applied to unstable systems directly. In this paper, a new idea of combining the Ziegler-Nichols PID controller tuning algorithm with the Taguchi Method is proposed. The Taguchi Method is introduced not only to improve the performance of the system but also to adapt the procedure for unstable systems. Therefore, it makes the Ziegler-Nichols PID tuning algorithm more widely applicable, and it achieves the better performance indices more quickly. Keywords: PID controller, Ziegler-Nichols tuning algorithm, Taguchi Method.