Distributed State Estimation Over Time-Varying Graphs: Exploiting the Age-of-Information

• 成果类型: Article
• 署名作者: Mitra, Aritra; Richards, John A.; Bagchi, Saurabh; Sundaram, Shreyas
• 署名单位: Purdue University System; Purdue University; United States Department of Energy (DOE); Sandia National Laboratories
• 刊物名称: IEEE TRANSACTIONS ON AUTOMATIC CONTROL
• ISSN/ISSBN: 0018-9286
• DOI: 10.1109/TAC.2021.3130882
• 发表日期: 2022
• 页码: 6349-6365
• 关键词: Asymptotic stability; CONVERGENCE; laboratories; Linear systems; observers; Real-time systems; Stability criteria

摘要

We study the problem of designing a distributed observer for an LTI system over a time-varying communication graph. The limited existing work on this topic imposes various restrictions either on the observation model or on the sequence of communication graphs. In contrast, we propose a single-time-scale distributed observer that works under mild assumptions. Specifically, our communication model only requires strong-connectivity to be preserved over nonoverlapping, contiguous intervals that are even allowed to grow unbounded over time. We show that under suitable conditions that bound the growth of such intervals, joint observability is sufficient to track the state of any discrete-time LTI system exponentially fast, at any desired rate. We also develop a variant of our algorithm that is provably robust to worst-case adversarial attacks, provided the sequence of graphs is sufficiently connected over time. The key to our approach is the notion of a freshness-index that keeps track of the age-of-information being diffused across the network. Such indices enable nodes to reject stale estimates of the state, and, in turn, contribute to stability of the error dynamics.