A class of non-contractive, trial-dependent update rules for iterative learning control

In this paper, a family of trial-dependent update laws is studied and contrasted with a class of fixed update laws. In particular, it is investigated whether the principle of equivalent feedback extends to trial-dependent update laws. It turns out that this is not the case. Nonetheless, it is shown that a well-known performance bound arising in feedback control architectures, Bode's sensitivity integral, also applies here.