The adaptive robust control scheme introduced by Veres and Sokolov (Automat
ica, 34, 723-730) provides optimal asymptotic performance under unmodelled
dynamics, unknown disturbance bounds and unknown model orders that make the
scheme desirable in practical applications. The amount of numerical comput
ations associated with that scheme is large because of the possible large c
omplexity of the appearing polyhedra. The geometrical details of the polyhe
dra need large memory space and their updating a lot of computation. This n
ote gives a modification of the scheme so that polyhedron complexity is lim
ited. Asymptotic performance of the scheme is the same as that of the origi
nal adaptive scheme in Veres and Sokolov (1998), transient performance can
be worse. Simulation illustrates that practical implementation of the schem
e is feasible. (C) 1999 Elsevier Science Ltd. All rights reserved.