Analytical Approach-Based Approximation of Higher-Order System Using Reduced-Order Modeling

The analytical approach-based approximation for the determination of reduced-order (RO) models for higher-order (HO) continuous systems is presented in this research work. The RO model for the HO system is obtained by incorporating the Routh array (RA) method and differential equation (DE) method by determining the unknown coefficients of the numerator and denominator. The fourth-order HO continuous system is considered for presenting the efficacy of the hybrid RO modeling method by proposing a second-order reduced-order model. The proposed second-order model is compared with the models proposed by researchers in the literature. In this analytical approach, step response and pole-zero plot along with impulse and Bode responses are considered for comparison. The tabular comparison is also provided in terms of values of time-domain specifications and errors with respect to the HO system.