Closed-loop identification of MIMO systems: An excitation-free approach

Abstract

In general, the external excitation is indispensable for closed-loop identification of SISO and MIMO systems. In this paper, an excitation-free approach for closed-loop identification of multi-delay MIMO systems is proposed by using the routine operating closed-loop data. Both identifiability and consistency of the plant model estimation are achieved when the basic assumptions are met. The proposed approach provides an effective way to handle closed-loop identification of MIMO systems, while it becomes of a non-trivial task for the conventional identification methods and especially subspace identification method in lack of prior knowledge on the process. The effectiveness of the proposed approach is demonstrated by a $4\times 4$ industrial example viz. the Alatiqi column.