IEEE 1856-2017 pdf free download – IEEE Standard Framework for Prognostics and Health Management of Electronic Systems.
4. Requirements
The following shall be applicable with regard to prognostics and health management for electronic systems:
a) A prognostics and health management system shall consist of sub-systems and components with capabilities including:
1) Acquisition of object system data (e.g., by means of sensors),
2) Data management, and
3) Data processing algorithms and/or processes for:
i) Diagnostics, health state estimation, and prognostics
ii) Health management
b) The PHM system shall be developed in accordance with IEEE Std 15288 6 or an equivalent standard as defned in the PHM or object system specifcations.
c) The PHM software and/or frmware shall be developed in accordance with IEEE Std 12207 or equivalent standard as defned in the PHM or object system specifcations.
d) PHM system performance is measured for its contribution to achieving or improving object system goals. PHM system performance shall be measured in terms of metrics chosen from the following categories:
1) Accuracy: Accuracy is a measure of deviation of a prognostic or diagnostic output of current object system state from measured, observed, or inferred ground truth. Accuracy shall be measured by comparing prognostic and diagnostic outputs from measured ground truth using several metrics (Saxena, et al., 2010 [B14] 7 ) such as, but not limited to, detection accuracy, isolation accuracy, and prognostic system accuracy. These terms are defned in the normative defnitions section above.
2) Timeliness: Timeliness is a measure of how quickly the PHM system’s functions produce their outputs in relation to the failure efects that they are mitigating. Overall timeliness includes the total time of state estimation and control for the PHM Control Loop. The timeliness from prediction or detection through response shall be summed up to compare to the time required for the failure mitigation. If desired, comparisons for the prognostics function and the health management function shall be made separately by grouping the relevant sub-functions. The timeliness aspects of the PHM sub-functions that contribute to the total PHM Loop include detection time, diagnostic time, prognostic time, decision time, and response time. These terms are defned in the normative defnitions section above.
3) Confdence: Confdence is a measure of trust (or, conversely, a measure of uncertainty) in a PHM system’s output. For detection and diagnostic functions, it is computed through, but not limited to, robustness, sensitivity, and uncertainty metrics. For prognostics it is specifed by including the estimation of uncertainty in predictions and stability of predictions over time, in addition to sensitivity and robustness measures (Saxena, et al., 2010 [B14]).
4) Efectiveness: Efectiveness is a measure of the PHM system’s ability to preserve or attain relevant system goals. Typical efectiveness goals include system reliability, safety, performance, cost, or schedule. The sub-metrics of accuracy, timeliness, and confdence shall be combined for specifc PHM mechanisms and for the PHM as a whole for the system to generate the PHM efectiveness measured against the relevant system goals, as allocated to PHM. 5) And, any additional metrics as defned in the PHM or object system specifcations.
e) PHM system performance shall be tracked over time to determine if a need exists to either update the PHM system (e.g., models, instrumentation, algorithms, rules, etc.) or performance measurement methods and metrics. The tracking system shall be capable of documenting all anomalies and failures during testing and operation, including tests and analyses to confrm them. The tracking system shall also document the outcomes and reports of the resulting investigations, design and operational modifcations, and the results of tests of these modifcations. Finally, the tracking system shall be capable of generating metrics regarding all of the above.
NOTE—The illustrations and notes presented in this Clause are provided to help the reader to understand the concepts and are not a requirement of the standard.IEEE 1856 pdf download.