A New Combined Approximation for the Reduction of Discrete-Time Systems Using Routh Stability Array and MSE

이감직신간 제어계에 있어서 Routh안정기열과 MSE 을 이용한 새로운 혼합형 모델 절기법

A new combined approximation method using Routh stability array and mean-square error (MSE) method is proposed for deriving reduced-order z-transter functions for discrete time systems. The Routh stability array is used to obtain the reduced-order denominator polynomial, and the numerator polynomial is obtained by minimizing the mean-square error between the unit step responses of the original system and reduced model. The advantages of the new combined approximation method are that the reduced model is always stable provided the original model is stable and the initial and steady-state characteristics of the original model can be preserved in the reduced model.