Performance Analysis of a Model-Free Predictor for Delay Compensation in Networked Systems

One important challenge with networked systems is that communication delays can significantly deteriorate system performance. This paper considers a model-free predictor framework to compensate for communication delays and improve networked system performance, where the term "model-free" indicates that the predictor does not need to know the dynamic equations governing the system. Stability analysis of this predictor is available in the literature; however, ensuring stability does not guarantee a good performance. Understanding when the predictor can perform well and what its limitations are is critical, but the performance characteristics of the predictor are unknown. Hence, this paper aims to fill this gap by providing a predictor performance analysis for constant time delays. First, a frequency-domain analysis is performed for the predictor and the relationship between the predictor design parameter, time delay, and steady-state performance is revealed. Fundamental limitations of the predictor at higher frequencies are laid out. Next, this analysis is confirmed on a case study. The case study further allows for testing the transient performance of the predictor in closed-loop with the networked system, and shows that the predictor holds significant potential to alleviate the negative impact of communication delays, even if its higher frequency performance may be limited. © 2015, IF AC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.