ScienceAsia 32 (2006): 241-251 |doi: 10.2306/scienceasia1513-1874.2006.32.241

Robust Discrete-Time Feedback Error Learning

Sirisak Wongsura^* and Waree Kongprawechnon^**

 
ABSTRACT: In this study, a theoretical foundation and stability analysis on the Discrete-Time Feedback Error Learning (DTFEL) method is discussed. The motivation to propose this method is to develop it as a readyto- use digital controller. However, it is presently available only for controlling a stable and stably invertible plant. This limitation is an obstacle to apply this method to the real systems where most plants are noninvertible. This study proposes a method to relax this constraint. This extension is based on the addition of a prefilter. Additionally, same as another type of adaptive controlled systems, DTFEL alone is very sensitive to the system disturbance and it may cause the system to be unstable. This robustness problem can be solved by integrating the Anti-Fluctuator(AF) to DTFEL system. The analysis shows how the system fluctuation is removed. Some numerical simulation results are given to illustrate the effectiveness of the method.

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School of Communications, Instrumentations and Control, Sirindhorn International Institute of Technology, Thammasat University, Pathumthani 12121, Thailand.

* Corresponding author, E-mail: sir_isak@yahoo.com* and waree@siit.tu.ac.th**

Received 3 Jun 2005, Accepted 29 Mar 2006