Markov-Parameters and Time-Moments Based Approximation of Discrete Interval Systems

This paper proposes the model order reduction (MOR) method for discrete interval systems (DISs). Two expressions are derived to calculate time moments (TMs) and Markov parameters (MPs) of DISs. The expressions of TMs and MPs are expressed in generalized form. MOR of DIS is obtained with the help of TMs, MPs, and pole retention techniques. The denominator of the model is obtained by the dominant pole retention technique. The numerator is calculated by matching the TMs and MPs of the higher-order system and lower-order model. One test case is included to illustrate the procedure.