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 previouslypublished experimental PI tuning method developed for standard sampling and the adaptation of thismethod to the SSOD sampling case. It is well known that the SSOD sampling strategy may induce per-manent oscillations in the closed loop if the controller is not designed properly. The proposed approachavoids those oscillations through fixing some limitations in the tuning parameters using only the experi-mental step response measurements as input data. The result is an experimental PI tuning method, basedonthreesimplemeasurementsinthestepresponse,thatguaranteestheabsenceofoscillationswhenSSODsampling is used in the loop.