New robustness measure for a kind of event-based PID

In this paper we present a study of the appearance of limit cycles in event-based PID control systems. Our approach is based on the extension of the Tsypkin method, which has been widely used to study the relay control systems. A new margin has been obtained to measure the robustness to limit cycles of continuous controllers when applied on event based control loops. The margin has been calculated to characterize some well known PID controllers tuning methods applied to the control of FOPTD systems with SSOD sampling strategy.