Through-Life Monitoring of Resource-constrained Systems and Fleets

A Digital Twin (DT) is a representation of a physical system that provides information to make decisions that add economic, social or commercial value. DTs are widely used for prognostics and anomaly detection by continuously comparing measured system behaviour with the DT predictions to identify deviations and estimate degradation. The behaviour of a physical system changes over time; a DT must therefore be continually updated with data from the physical system to reflect its changing behaviour. In this paper, we consider a DT of a complex, non-linear and dynamic system subject to slow nominal degradation, disturbances and the risk of anomalies. The DT runs on a resource-constrained system, making up dating non-trivial due to limitations in computation, storage,and data transfer bandwidth. Consequently, only a subset of the generated data can be retained or transmitted, making data prioritisation essential. Data must be evaluated online in order to select the most relevant subset with which to perform the update. DT updating must address the continual learningchallenge of adapting to new system behaviours, such as the response to previously unseen operating conditions, while retaining knowledge of previously observed behaviours. This paper presents a framework for updating a data-driven DT of a resource-constrained system. The proposed solution consists of: (1) an on-board, lightweight DT that enables the prioritisation and parsimonious transfer of data generated by the physical system; and (2) an off-board system for robust DT updating that enables the reliable detection of anomalous be haviours across the asset’s lifetime. The framework allows the DT to accurately replicate the behaviour of the system throughout its life, improve sensitivity to anomaly detection, and reduce the risk of forgetting previous system behaviours after updating the DT. An in-service gas turbine engine case study is used for demonstration.