Toward intelligent control

The problem of automatic tuning of simple regulators is examined. The key idea is to design an aid for the process operator, which should use minimal prior information about the system. This is a typical example of a case where it is essential to develop techniques that will give crude but robust estimates. The development has resulted in a novel generation of the classical PID (proportional, integral, and derivative) controller. An application of relay autotuning to temperature control of a distillation column is considered as an example. Adaptive control is then treated. The adaptive algorithms can be viewed as local gradient methods. They require prior information but, given the information, can give very good control performance. The use of an expert system to integrate the two approaches is then discussed.<>