Some New Results on Current Iteration Tracking Error ILC

Frequency domain convergence conditions for Current Iteration Tracking Error (CITE) Iterative Learning Control (ILC) algorithms are presented. The convergence conditions together with a discrete-time version of Bodes integral theorem imply a strong restriction upon the kind of systems that can be controlled using a CITE ILC algorithm. The restriction is caused by the fact that the filter in the ILC algorithm has to be causal and and part of a closed loop system that has to be stable