A NOTE ON CONVERGENCE PROPERTY OF ITERATIVE LEARNING CONTROLLER WITH RESPECT TO SUP NORM

We discuss some undesirable phenomena associated with the lambda-norm that is used in the proof of convergence of the iterative learning con troller (ILC). Specifically, we first report that huge overshoot may b e observed in the output trajectory error, even though the applied lea rning algorithm has been proved to be exponentially convergent with re spect to the lambda-norm. This is because of the way in which the lamb da-norm converges differs from that of the sup norm. We then investiga te the relation between the lambda-norm and the sup norm. Finally, we present a simple method to remedy the undesirable feature of the conve ntional ILC. (C) 1997 Elsevier Science Ltd.