Applied Process Control

6Estimation of Variables and Model Parameters from Plant Data

In this chapter, the idea of ‘observer models’ will be developed. The use of digital computers in industry, and even computerised measurement instruments, has led to the notions of ‘intelligent sensors’, ‘soft measurements’ and ‘data mining’. An example might be the varying temperature in the centre of cooling cast steel ingots, estimated from the surface temperature. Such calculated variables were considered briefly in Section 4.6, but the more complex issues of state and parameter estimation during dynamic variation, for multivariable systems, must be considered in more detail here owing to the growing importance of these techniques industrially.

Figure 6.1 shows the general case ...