Regulation as an interpolation problem

Cevik M., Schumacher J.

LINEAR ALGEBRA AND ITS APPLICATIONS, vol.253, pp.311-340, 1997 (SCI-Expanded) identifier identifier


The design of a controller such that the closed-loop system will track reference signals or reject disturbance signals from a specified class is known as the ''servomechanism problem'' or the ''regulator problem.'' We show here that the regulator problem can be looked at as an interpolation problem for a subspace-valued function that can be viewed as a multivariable version of the Nyquist curve. The result is applied to obtain a simple parametrization of all solutions. (C) Elsevier Science Inc., 1997.