  In this paper, the use of the Smith-McMillan form in decoupling
multiple-input multiple-output system dynamics is analyzed. In short, from a
transfer matrix plant model one can obtain a decoupling compensator which leads
to a decoupled plant that contains the same transmission poles and zeros of the
transfer matrix of the original system. As a result, full decoupling of the
plant transfer matrix is obtained for all frequencies, which can be
individually addressed by single-input single-output control. The aim of this
paper is to present conditions for the decoupled system that guarantee internal
stability and performance requirements for the overall control system.
Performance specifications are defined in terms of magnitude limits for the
maximum singular value of the closed-loop transfer matrices. The potential of
the decoupling procedure is shown in a simulation study of a mechanical system.
