Experimental tuning of PI controllers with symmetric send-on-delta sampling from the step response

Abstract

This paper proposes a technique for tuning PI controllers with symmetric send-on-delta (SSOD) sampling, using three measurements taken from the step response. The tuning procedure is based on a previously published experimental PI tuning method developed for standard sampling and the adaptation of this method to the SSOD sampling case. It is well known that the SSOD sampling strategy may induce permanent oscillations in the closed loop if the controller is not designed properly. The proposed approach avoids those oscillations through fixing some limitations in the tuning parameters using only the experimental step response measurements as input data. The result is an experimental PI tuning method, based on three simple measurements in the step response, that guarantees the absence of oscillations when SSOD sampling is used in the loop.