Variable measurement structures for process control

The idea of using variable measurement structures for chemical process control is an attractive one hut in the past it has encountered significant computational and implcmcntationul difficulties. In the present. work an online sequential analysis of the measurement equations is presented, which allows fur a fast and robust updating of the best measurement st.ruot.uro for the control of several processing systems where updating the measurements’ configuration would result in a robust control behaviour. The present paper develops the theoretical foundations for the concept of the variable measurement structures, and implements it for systems operating in a pacudo steady state or dynamic environment. Furthermore, a strategy is developed for the identification of the optirnurn measurement structure in the presence of disturbances. finally the concept of variable measurement structures is discussed with reference to the control of two processing units of interest to the chemical industry; a distillation column and a tubular chemical reactor.