Modeling of nonlinear systems using extended self-organizing map

Local model networks (LMN) have been shown to be an effective approach for modeling nonlinear systems. Despite recent advances of LMN, a prior knowledge of the process is necessary for determination of LMN structure and weighting function. To overcome these problems, an extended self-organizing map (ESOM) was recently developed. However, the stability of local models is not addressed in this previous work. In this paper, an improved ESOM algorithm is proposed and its application is illustrated by using a CSTR example. Based on the ESOM models obtained, a global PID controller is designed and its robustness is examined. Simulation results verify that ESOM can be used conveniently in modeling and controlling of the processes that are subject to multiple operating regime.