STRONG STABILIZATION OF MIMO SYSTEMS VIA UNIMODULAR INTERPOLATION IN H-INFINITY

In this paper, the strong stabilization problem of multivariable linea r time-invariant systems is considered. The problem is categorized int o minimum and non-minimum phase systems. When the given system is mini mum phase, the solution requires a stable inverse of a particular stab le transfer function matrix; while for a non-minimum phase system, the solution requires an inner-outer factorization, whose outer part is u nimodular in RHinfinity and an interpolation in RHinfinity. The formul ation of the two cases will be modified so that the conditions for the existence of stable inverse or unimodularity of the outer part are sa tisfied. When the system is strictly proper it is shown that the probl em is more technically involved.