The main contribution of this paper is a recursive algorithm for param
etric system identification in the presence of both noise and model un
certainties. The estimates provided by this algorithm are not invalida
ted, after a learning period, by the observed input-output data and th
e assumed system and uncertainty structures. A complementary off-line
algorithm derived from the on-line algorithm is also presented. (C) 19
97 Elsevier Science B.V.