Redundant Acquisition Channel Fault Localization with Delayed Thresholds
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Solution Overview
Problem
Current failure management strategies in duplex acquisition systems, such as those in turbomachines, suffer from high rates of incorrect localization, leading to potential amplification of faults due to the simultaneous detection and localization phases being driven by different accuracy parameters, which can result in unsafe regulation systems.
Innovation Solution
A method is introduced where failure detection and localization are distinguished by using separate thresholds and a waiting period to allow the deviation between channels to grow, enabling more accurate localization by comparing channel values with a model-based threshold, thereby reducing the risk of incorrect channel selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If failure detection and localization are performed simultaneously using the same threshold, then the response time is reduced, but the localization accuracy deteriorates leading to wrong channel selection
Solution Approach 1:
The patent divides the failure management process into two distinct phases: a detection phase using a first threshold, and a localization phase using a second threshold. This segmentation allows each phase to be optimized independently, with the detection phase focusing on rapid fault identification and the localization phase focusing on accurate channel identification, thereby resolving the contradiction between response time and localization accuracy.
Solution Approach 2:
The patent introduces a waiting period between detection and localization, during which the system allows the deviation to grow. This preliminary action of waiting for the deviation to amplify makes subsequent localization more accurate by providing a clearer signal, thus improving localization accuracy without significantly penalizing the overall response time.
2Reliability
If the arithmetic mean of both channels is used in nominal operation, then the impact of a single channel failure is reduced, but the system becomes vulnerable to wrong localization amplifying the error
Solution Approach 1:
The patent implements a feedback mechanism where the system continuously monitors the deviation between channels and uses this information to dynamically adjust the selection strategy. When deviation is below the first threshold, the mean is used for fault tolerance. When deviation exceeds the second threshold, the system switches to model-based localization. This feedback-driven approach ensures the system benefits from fault tolerance when appropriate while avoiding error amplification when faults are present.
Data Source
AI summary
A method detects and localizes a failure of a measurement acquisition channel in an acquisition system including two redundant acquisition channels for the measurement of a physical quantity in an environment. The method uses a processor with a memory storing a model including modeled values of the physical quantity based on measurements of other physical quantities in the environment. The method includes detecting a symptomatic error of a defective acquisition channel when a deviation between the measured values of the two channels reaches a detection threshold, waiting to let the acquisition system evolve for a certain period, and localizing the defective channel among the two channels, when the deviation of the values measured between the channels reaches a localization threshold different from the detection threshold. The localization is made from the comparison of the measured value of each of the channels with a modeled value of the physical quantity.