Servo Loop Degradation Detection in Jet Engine Actuators
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Solution Overview
Problem
Current monitoring methods for servo loops in turbojet engine actuation systems are ineffective in detecting degradations early enough to prevent inefficiency or failure, often leading to late maintenance and unnecessary operations.
Innovation Solution
A method and device for monitoring servo loops in turbojet engine actuation systems that estimate various parameters, such as cylinder positions and autoregressive model coefficients, to detect and locate degradations by analyzing signatures derived from these parameters, allowing for predictive maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional monitoring methods are used, then the system structure remains simple, but degradation detection is too late and maintenance is unnecessary frequent
Solution Approach 1:
The monitoring system segments the actuation system into multiple components (servovalve, actuators, cylinders) and monitors each separately using dedicated sensors and parameter estimation techniques. This allows targeted detection of degradations in specific components without requiring a complete system overhaul, resolving the contradiction between early detection and system complexity.
Solution Approach 2:
The system performs preliminary monitoring and parameter estimation continuously during normal operation to detect degradations before they lead to failure. By estimating parameters like cylinder positions and servovalve control currents in advance and comparing them against expected values, the system identifies degradation trends early, enabling proactive maintenance before the actuation system becomes inoperative.
2Measurement precision
If comprehensive monitoring parameters are estimated, then degradation detection accuracy improves, but computational load and processing time increase
Solution Approach 1:
The monitoring system focuses computational resources on estimating parameters for specific critical components (cylinder positions, servovalve control currents) rather than monitoring all system parameters equally. This localized approach maintains high detection accuracy for degradation-prone components while reducing overall computational burden and processing time.
Solution Approach 2:
The system monitors changes in key parameters (cylinder position deviations, control current variations) over time rather than analyzing absolute values. By tracking parameter trends and deviations from expected behavior, the system achieves accurate degradation detection with reduced computational complexity, as it only needs to detect significant changes rather than process complete parameter sets continuously.
3Productivity
If early maintenance is implemented, then engine availability improves, but unnecessary maintenance operations increase
Solution Approach 1:
The monitoring system continuously compares estimated parameters against expected values and provides feedback on system health status. By analyzing trends in parameter deviations and comparing them against degradation thresholds, the system distinguishes between normal variations and actual degradations, enabling maintenance to be scheduled based on actual condition rather than fixed intervals, thus avoiding unnecessary maintenance while ensuring timely intervention when needed.
Data Source
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AI summary
The invention relates to a method comprising: estimating monitoring parameters from operating data of the feedback loop; obtaining indicators from the monitoring parameters; determining at least one signature from values of at least one portion of the indicators; and detecting and locating a degradation affecting the feedback loop according to said at least one predetermined signature.