Heuristic investigation on two step model order reduction technique

The authors deliver the comparative study between the directly reduced systems and step wise reduced systems. In this paper reduced order model corresponding to a higher order model, say T, in two steps using HSIA's method has been found. This method is very simple and gave stable reduced order system corresponding to the stable original system. This method is used twice to find the final reduced order system. First an intermediate lower order system, is found and then the final lower order system, say system T1, is obtained in a two step manner. Another reduced order model is obtained directly without any intermediate steps from higher order system to desired reduced order, say T2. A comparison is presented between the responses of reduced models T1, T2 and the response of the original system, T. The comparison of the responses is illustrated with an example which vindicates that the response corresponding to, T1 is more closer to the response of the original system, T than that corresponding to T2.