Almost noninteracting control design using dynamic state feedback

In this paper we will solve, for finite dimensional linear time invariant systems, the problem of the existence of a dynamic state feedback control law such that in the closed loop system the exogenous variables are noninteracting to any arbitrary degree of accuracy. The solvability conditions for this problem involve the recently introduced notion of ‘almost A(mod B)-invariant subspaces’, much in the same way as the completely noninteracting control design involves A(mod B)-invariant subspaces.