Robustness of event-based discrete PI controllers. A sampled describing function approach

Abstract

In this paper we present a study about the robustness of event-based discrete PI controllers. Our approach is based on Sampled Describing Function technique, which has been used to characterize the non-linear effect of the Symmetric Send on Delta (SSOD) sampling strategy on the control loop. Through several examples this technique is proven to produce accurate results in predicting limit cycle oscillations and to provide guidelines to avoid them, either by detuning the controller or increasing the sampling period.