Modeling of soft sensor for chemical process

In the commercial chemical process, many primary product variables cannot be measured online, and soft sensor is an important means to solve this problem. Soft sensing modeling is the core issue of soft sensor. The relationship between soft sensing modeling and identification and nonlinear modeling is presented. The dynamic relationship between quality variables and variables that are easy to measure exists between the increments, and identification depends on incremental data, while soft sensing modeling depends on the measured data to get the relationship. Nonlinear modeling establishes the static relationship between these variables, ignoring the dynamic characteristics, which soft sensing modeling should take into account. With deeper understanding of the chemical process properties, the types and structures of soft sensing model have undergone a great change in the last decades, and soft sensing modeling method evolves from mechanism modeling to data-driven modeling, from linear modeling to nonlinear modeling, and from static modeling to dynamic modeling. The development of the soft sensing modeling method is reviewed. The advantages and disadvantages of the proposed methods are analyzed, and the applications of these methods are shown. In the end, the hot issues and the directions of development of soft sensing modeling method are presented. © All Rights Reserved.