Identification of Closed Loop Subsystems in Large Scale Systems

Abstract

Abstract Identifiability of closed loop subsystems in large scale systems is considered. Here in contrast to separate closed loop systems all outer signals influencing the closed loop may be correlated. For the general case that all outer signals are correlated the corresponding solutions for the determination of the process dynamics according to the direct method, the indirect method and the correlation method are derived. It is shown that only some definite correlations of the outer signals must be known a priori. Moreover, it is shown that the solutions obtained for uncorrelated outer signals can also be applied to the identification of closed loop subsystems successfully if in addition definite conditions on some of the correlated outer signals are fulfilled. The results obtained are of practical relevance for an optimal design of identification experiments in large scale systems.