"Combination of measurements as controlled variables for self-optimizing control"
Vidar Alstad and Sigurd Skogestad

Presented at ESCAPE-13, Lappeenranta, Finland, June. 2003

A new method for selecting controlled variables (c) as linear combination of 
measurements (y) is proposed based on the idea of self-optimizing control. 
The objective is to find controlled variables, such that a constant setpoint 
policy leads to near optimal operation in the presence of low frequency 
disturbances (d). We propose to combine as many measurements as there are 
unconstrained degrees of freedom (inputs, u) and major disturbances such that 
Delta c_{opt}(d)=0. To illustrate the ideas a gas-lift allocation example is 
included. The example show that the method proposed here give controlled 
variables with good self-optimizing properties.