Comparison of the Time-Delay Margin of a Distributed and Centralized Observer

International audienceThe benefit of a distributed observer concept for large-scale linear plants is shown by taking time-delays into account. It is asserted that a centralized observer suffers from delays in the measurement input, while a distributed structure allows to avoid them. In contrast, the network of the distributed observer induces communication delays among observer nodes. The delay margins for both observer concepts are estimated on a numerical example and compared using an eigenvalue-based frequency domain approach and an LMI based time-domain approach

Distributed observers with time-varying delays

International audienceThe distributed estimation problem is solved for continuous-time observer nodes that obtain real-time measurements but communicate with their neighbors over a communication network. To this end, the digital communication between the observer nodes is modeled by the time-delay approach where variable sampling intervals, transmission delays and packet dropouts are taken into account. An LMI for the design of the observer gains is derived using Halanay’s inequality, the feasibility of which guarantees exponential stability with a selected convergence rate up to a maximum total delay. A comparison of the maximal delay on a numerical example shows the advantage of a distributed observer over a centralized one