Hybrid method of reduced order modelling for LTI system using evolutionary algorithm

This study presents a hybrid technique to achieve lower order model of higher order linear time invariant (LTI) system. The order of denominator has been reduced, using stability equation method, whereas modified cuckoo search algorithm has been utilized to achieve numerator polynomial of lower order systems through minimizing integral square error (ISE). The proposed approach is applied on higher order single input single output (SISO) and multi input multi output (MIMO) systems to obtain their reduced order models. Further, various performance indices and time response characteristics of the proposed lower order model have been evaluated. Finally, for the same higher order systems, the results of reduced order model obtain with hybrid of `stability equation method & GA' and `factor division algorithm & Eigen spectrum analysis' are evaluated and compared with the results of proposed reduced order model. The comparative analysis shows that the characteristics of proposed model are closer to the original higher order systems than the other hybrid methods. Also, performance measures, like, ISE, integral absolute error (IAE), and integral of time multiplied by absolute error (ITAE), for proposed model are found smaller than the others.