An improved method for reduction of continuous interval systems using Anderson corollary

Abstract

Engineering systems are modeled as interval systems recently. In this paper, an improved technique for model reduction of high-order continuous interval systems is presented using Anderson corollary and Routh approximation. The distinguishing features of the proposed method are: (i) it ensures exact matching of responses of reduced-order interval model and high-order interval system at steady-state; (ii) it retains interval-value of steady-state of high-order interval system; and (iii) it produces interval model for interval system. Firstly, the denominator of the reduced-order model is obtained based on Routh table. Then, the numerator is obtained by matching the interval-values of steady-state of high-order interval system and reduced-order interval model. A single-input-single-output (SISO) test system is considered to explain the efficiency of the proposed method. The step responses of SISO test systems are obtained and presented for comparative study. From the results, it is observed that the proposed method provides better approximants.