Frequency‐domain‐based iterative learning control utilizing n‐best adaptive Fourier decomposition for nonrepetitive unknown iteration‐independent and iteration‐varying discrete time‐delay systems

Abstract

AbstractThe bulk of well‐known control techniques for time‐delay systems are sensitive to the system's uncertainty. For unknown nonrepetitive iteration‐independent and iteration‐varying linear discrete time‐delay (LDTD) systems, an iterative learning control (ILC) design with a frequency domain identification technique is devised. The proposed ILC method is based on a novel n‐best adaptive Fourier decomposition (n‐BAFD) approach for approximating the unknown time‐delay transfer function. An extended anticipatory ILC law is developed that uses anticipatory time to compensate for both iteration‐independent and iteration‐varying time delays in the frequency domain for unknown nonrepetitive LDTD systems. Three examples are used to validate the proposed frequency‐domain‐based ILC method.