Lubrication Particle Sensor Using Autoregressive Resistance Modeling
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Solution Overview
Problem
Existing aircraft engine monitoring systems using electromagnetic sensors face challenges in accurately detecting the start of terminal wear phase due to high false alarm rates caused by difficulty in determining a suitable resistance threshold, which is influenced by various parameters.
Innovation Solution
A monitoring process that involves determining an autoregressive mathematical model from resistance measurements, comparing it to a reference model, and evaluating the spectral characteristics to detect changes, thereby reducing false alarms and providing a maintenance opinion based on a predefined threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high resistance threshold value is used to avoid missing critical wear situations, then safety is improved, but the false alarm rate increases
Solution Approach 1:
The patent transitions from a static threshold value to a dynamic threshold that adapts based on operating conditions. The system continuously monitors resistance measurements and adjusts the threshold dynamically according to the current operational context, allowing it to maintain high safety while reducing false alarms caused by fixed threshold limitations.
Solution Approach 2:
The patent changes the parameter used for threshold determination from a fixed resistance value to a dynamically calculated threshold based on multiple factors including operating conditions, historical data, and statistical analysis. This parameter transformation enables the system to differentiate between normal variations and actual wear events.
2Object-generated harmful factors
If a low resistance threshold value is used to reduce false alarms, then the false alarm rate decreases, but critical wear situations may be missed
Solution Approach 1:
The patent implements a feedback mechanism where the system continuously monitors resistance measurements, compares them against dynamically adjusted thresholds, and learns from the outcomes. This closed-loop approach allows the system to maintain sensitivity to critical wear while filtering out false alarms through continuous validation and adaptation.
Solution Approach 2:
The system performs preliminary analysis of operating conditions and historical data before setting the threshold, preparing the monitoring system in advance to correctly interpret resistance measurements. This preliminary action enables the system to anticipate when low resistance values represent actual wear versus normal operational variations.
3Ease of operation
If a fixed threshold value is used for resistance measurement, then the system is simple to operate, but it cannot adapt to varying operating conditions
Solution Approach 1:
The patent enables the monitoring system to self-adjust its threshold values automatically based on observed operating patterns and conditions. The system performs self-diagnosis and self-calibration, eliminating the need for manual threshold setting while maintaining operational simplicity for the user.
Solution Approach 2:
The system transforms the static threshold into a dynamic parameter that automatically adapts to changing operating conditions. This dynamic adjustment occurs transparently in the background, maintaining ease of operation while significantly improving adaptability to various engine states and environmental conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively detects the start of the terminal wear phase by analyzing spectral changes, reducing false alarms and improving the reliability of maintenance alerts.
Implementation Method 1
an electromagnetic plug is equipped with a magnet surrounded by two conductive electrodes insulated from each other... When a large quantity of metallic particles circulates in the lubrication system, the latter are captured by the magnet
Implementation Method 2
the latter are captured by the magnet and shunt (i.e. short-circuit) the gap of the electromagnetic plug, making contact between the two electrodes. The resulting contact causes a drop in resistance measured between the electrodes
Data Source
AI summary
A process for monitoring a machine including moving pieces, a lubrication system and an electromagnetic sensor fitted with a magnet and two electrodes is disclosed. The sensor is capable of collecting particles present in the lubrication system between the electrodes. The monitoring process includes a step for obtaining measurements of resistance between the electrodes of the sensor, taken during an operating period of the machine; a step for determining from said measurements a first autoregressive mathematical model characterizing the resistance; a step for comparison between the first model and a predetermined reference model; and a step for working out an opinion on maintenance of the machine as a function of the comparison result.