Threshold-Based Prognostics Action Index for Device Reliability
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Solution Overview
Problem
Existing prognostics and health management (PHM) techniques for devices, such as fuel cell systems, primarily rely on baseline analysis rather than threshold limits, which can lead to delayed detection of undesirable operating conditions and stringent threshold settings, limiting proactive intervention and increasing the risk of catastrophic failures.
Innovation Solution
A method and system that monitor operational parameters by determining the differences between parameter values and their corresponding limits, calculating an action index based on the smallest distance, and assessing whether this index falls within a desirable range, allowing for early warnings and more lenient threshold settings to prevent device shutdowns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If baseline analysis is used for PHM, then device operation can be monitored, but detection of undesirable conditions is delayed and threshold settings become stringent
Solution Approach 1:
The patent transforms operating parameters into distance values that represent the preliminary distance to undesirable operating conditions (thresholds). By continuously calculating these distances and comparing them against action indices, the system performs preliminary detection before actual threshold violations occur, enabling early warning and proactive intervention rather than waiting for baseline deviations to manifest
Solution Approach 2:
The patent fundamentally changes the monitoring parameter from baseline deviation to distance-from-threshold. Instead of measuring how much a parameter deviates from normal operation, the system measures how close the parameter is to an undesirable threshold condition. This parameter transformation enables more lenient threshold settings while maintaining early detection capability
2Reliability
If stringent threshold limits are set for operational parameters, then device safety is improved, but false alarms increase and operational flexibility is reduced
Solution Approach 1:
The patent introduces an action index as an intermediary between the raw operational parameters and the threshold limits. The action index is calculated based on the distance values and serves as a mediator that translates complex multi-parameter distance calculations into a single comparable metric. This intermediary layer allows for more lenient individual parameter thresholds while maintaining overall system safety through the synthesized action index evaluation
Solution Approach 2:
The patent adds a new dimensional perspective by transforming scalar parameter values into distance values that represent spatial separation from undesirable conditions. This dimensional transformation creates a buffer zone between normal and undesirable operations, allowing operational flexibility within this buffer while maintaining safety margins
Data Source
AI summary
According to an embodiment, a method of monitoring the operation of a device includes determining a plurality of operational parameters that are indicative of an operation condition of the device. A difference between each operational parameter and a corresponding limit on that parameter is determined. Each limit indicates a value of the corresponding operational parameter that corresponds to an undesirable operation condition of the device. An action index is determined based on at least a smallest one of the determined differences. A determination is made whether the action index is within a range corresponding to desirable operation of the device.