Estudo de processos com atraso variavel controlados por compensadores PI

Abstract

This work presents a stability analysis for proportional-integral (PI) controllers for processes with constant delays and time-varying delays. It is frequently reported in the literature that the time delay in the feedback loop can lead the system to instability. This problem can be made worse if the delay is time-variant with, for example, a sawtooth variation, which is reported in the literature as one of the worst types of time-delay variation due to the phenomenon known as chattering. Therefore, this study allows us to assess whether the worst case scenario for a PI controller is the constant delay or the time-variant delay, in the sawtooth format. Finally, a simulation example presents the stability analysis of a very popular PI controller tuning rule in the literature, to determine whether the worst case scenario is constant delay or time-varying delay.