Model following using measured output feedback

This article considers the "partial state feedback model following problem" (PSFMFP) introduced by Howze et al. [5]. Here we give a more general statement of this problem and show that its solution is closely related to the existence of certain "(
D, A
)- invariant" controllability subspaces, where
D
is an output map connected with the measurable output. We also give a procedure for the synthesis of a dynamic compensator using less integrators than in [5].