A new worst-case iterative identification and control scheme is introduced
which is based on the use of unfalsified model sets in parameter space. No
a priori bounds are assumed on the norm of the 'unmodelled dynamics' or on
the size of disturbances. In spite of the weak assumptions, the scheme conv
erges close to an 'ideal' performance, which could be achieved only with pe
rfect knowledge of the size of the unmodelled dynamics and the disturbances
. An interesting feature of the scheme is that the model structure of the p
arametric part of the models does not have to be known a priori either. A f
inite set of alternative parametric models can be hypothesized. and structu
re selection is part of the iterative identification and control design sch
eme proposed. Finally, simulations are shown and numerical implementations
are discussed.