Aggregation by continued fraction method of model reduction: An application to SISO system

A number of model order reduction techniques have been proposed in the control system literature. One of the popular methods proposed for model order reduction is the aggregation method proposed by M. Aoki [8]. Aggregation matrix can be find out by a numbers of ways as suggested by a number of researchers in last few decades. In this paper aggregation matrix is obtained using continued fraction expansion method. This method is simple and it approximate the full order model very well in the low frequency region. In this article aggregation by continued expansion technique is applied to reduce a single input single output system. Original system is of the order of four, its third order and second order approximant is obtained. To check the dynamic behavior of the system step response of original and reduced model is compared.