Block-oriented NARMAX models with output multiplicities

Block‐oriented modeling approaches to the development of NARMAX models for processes exhibiting output multiplicities are introduced. “Feedback block‐oriented” model structures are proposed that can force the resulting NARMAX model to have a particular steady‐state behavior and reduce the model‐identification problem to a constrained, linear model identification. These models are particularly suitable for gray‐box modeling approaches where it is assumed that the steady‐state behavior of the process is known and a NARMAX model is sought to approximate its dynamic response. The proposed approaches are applied to a CSTR model with three steady states to illustrate their peformance.