Set point and identifiability in the closed loop with a minimum-variance controller

Abstract

The meaning of nonzero set points for the identifiability of the ARMAX model parameters in a closed-loop system with a minimum-variance controller is explained and discussed. It is pointed out that, in the case of a zero set point and an ARMAX model resulting from the discretization of a continuous-time plant, the model parameters cannot be identified in a closed-loop system with a minimum-variance controller. It is also shown that in the case of an appropriately varying set point or the existence of a delay in the plant, the identifiability conditions of the parameters can be fulfilled.