  The trajectory tracking problem for multivariable linear systems is
considered. Two different techniques are examined: the output regulation theory
(ORT) and the flatness based tracking (FBT). ORT and FBT are two different
approaches to solve the tracking problem, and both methods have different
restrictions. The tracking controller of the ORT furthermore depends on the
solution of the so-called regulator equations. In this paper, a special
analytic solution of the regulator equations is presented. Additionally, based
on this analytic solution, a link from the ORT to the FBT approach is provided,
and the connection of both tracking controllers is highlighted. It is shown how
the ORT controller can be converted to the FBT controller and that both methods
lead to identical control laws for a certain class of systems.
