Adaptive PID Regulators. Ambitions and Limitations

This paper deals with adaptive control of 'easy' processes, such as the familiar SISO, aperiodic systems. For such processes, the simple P.I.D. regulators perform quite well, provided that the main characteristics of the open-loop response are sufficiently well known. In the case of large uncertainties, the problem of adaptation is intrinsically difficult, mainly in the pure regulation mode: null or constant set point, presence of noises and ill-described disturbances. In order to emphasize this point of view, a benchmark for adaptive control of 'easy' processes is proposed. Then, we analyse the performances of a particular self-tuning controller, in order to confront the ambitions, and their limitations.