Soft Sensing - Advanced Control and Supervision of Mineral Processing Plants - page 143

Chapter 4
Soft Sensing
Guillermo D. Gonzalez
Abstract This chapter addresses different aspects of soft sensors and their impor-
tance, especially for mineral processing plants. It considers current state-of-the-art
soft sensors and the future outlook of the industry, taking into account different
classes of linear and nonlinear in-the-parameter soft sensor models, their design,
and soft sensor shell systems for providing a robust operation in industrial envi-
ronments. A geometrical approach to soft sensor modeling is given for nonlinear
but linear in-the-parameter models. Inclusion of phenomenology in linear in-the-
parameter models is highlighted. The chapter includes a review and examples from
the mineral processing industry.
4.1 Introduction
This chapter is concerned with the problem of availability of information provided
by measurements in plants either when sensors become unavailable or when they
have not been installed. The solution to this problem is approached by means of
soft sensors, i.e. , systems replacing the missing measurement (primary measure-
ment) with an estimation or prediction of the missing measurement based on the
other measurements (secondary measurements) correlated with the primary mea-
surement. A detailed analysis of soft sensors for industrial applications in general
is given by Fortuna et al. [1] where different topics and industrial applications are
covered. A summary of soft sensor topics may be found in [2]. However in [1],
cases of soft sensors used in mineral processing are not included. In this chapter, the
focus is on soft sensors in mineral processing plants, which due to their particular
characteristics require special attention to certain topics. In addition, by covering