Aperiodic principle for automatic controller tuning

Abstract

This paper presents simple principle for aperiodic tuning of SISO controllers used in autotuning. Autotuners represent a combination of relay feedback identification and some control design method. In this contribution, models with up to three parameters are estimated by means of a single asymmetrical relay experiment. Then a stable low order transfer function is identified. Further, the controller is derived from general solutions of Diophantine equations in the ring of proper and stable rational functions. A first order identification yields a PI-like controllers while a second order generates PID ones. The analytical simple rule is derived for aperiodic control response and the scalar tuning parameter m>0 is then tuned according to identified time constant of an approximated transfer function.