Abstract:
&very physical system can be translated into mathematical model. The mathematical model of large scale systems are very complex and they can not be reduced by hand canclulations. Fast digital computers can only be used to reduce these complex models.
The mathematical procedure of system modelling often leads to comprehensive description of a process in the form of high order differential equations, which are difficult to use either for analysis or controller synthesis.. It is hence useful and some - times necessary to find the possibility of finding some equation of the same type but of lower order that may be considered to adequately reflect the dominant characteristics of the system under consideration. Some of the reasons for using reduced order models of high order linear systems could be
(1) A system of uncomfortably high order poses difficulties in its analysis, synthesis or identification. So in its analysis, synthesis or identification an obvious method of dealing with such systems is to opproximate it by a low order system for which characteristics such as time constant, damping ratio, natural frequency and their inter relationships are well known....
