Controlling plants with delay

This paper studies a generalized form of the MIMO Smith regulator (GS) and one of its variants--the Gray-Hunt-Horowitz (GHH) regulator. The two schemes are analysed and the limitations imposed on system performance by uncertainty in delay, plant saturation etc. are exhibited. The GHH and GS regulators are compared with reference to a fairly general example. Finally, two theorems establish a global parametrization of all stabilizing controllers for the nonlinear GS and GHH regulators. A complete version of this paper is available from the authors.