Propeller Health Monitoring via Residual Pitch Angle Analysis
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Solution Overview
Problem
Current health monitoring systems for aircraft engine propellers are complex and often require unnecessary maintenance checks, lacking a simple and real-time method to detect blade damage and maintain propeller health.
Innovation Solution
A method that calculates the residual pitch angle difference between measured and predicted propeller pitch angles, comparing it to thresholds to assess propeller health and alert for maintenance, integrated with existing pitch angle detection systems like magnetic pickups and FADEC.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual blade analysis methods are used (time of arrival measurement, magnetic fields, 3D imaging), then blade damage detection capability is improved, but system complexity and cost increase significantly
Solution Approach 1:
The patent extracts the essential health monitoring function from complex individual blade analysis systems. Instead of measuring each blade's time of arrival, magnetic fields, or 3D position, the invention uses a single pitch angle sensor to detect overall propeller health changes. This extraction of the core monitoring function eliminates unnecessary complexity while maintaining damage detection capability.
Solution Approach 2:
The patent makes the pitch angle sensor serve multiple functions: it controls normal propeller operation and simultaneously monitors blade health. By making the sensor multi-functional, the system eliminates dedicated monitoring equipment, reducing complexity while maintaining detection precision through residual analysis of pitch angle data.
2Ease of manufacture
If existing pitch angle detection systems are used for both control and monitoring, then additional instrumentation costs are reduced, but the ability to distinguish between control adjustments and damage-induced changes is compromised
Solution Approach 1:
The patent performs preliminary analysis by comparing actual pitch angle measurements with predicted pitch angles calculated from performance models. This preliminary comparison establishes a baseline that separates normal control adjustments from damage-induced anomalies, enabling accurate damage detection using existing sensors.
Solution Approach 2:
The system uses feedback by continuously comparing residual pitch angles (difference between actual and predicted) against thresholds. When residuals exceed thresholds, the system triggers maintenance alerts. This feedback mechanism enables the single sensor to distinguish between control adjustments and damage with sufficient precision.
3Ease of operation
If routine maintenance checks are performed without real-time monitoring, then maintenance procedures are simple, but unnecessary maintenance checks are undertaken and damage warnings are delayed
Solution Approach 1:
The propeller monitoring system performs self-diagnosis by automatically analyzing pitch angle residuals and generating maintenance alerts. This self-service capability eliminates the need for complex external monitoring systems while enabling timely, condition-based maintenance that reduces both unnecessary checks and delayed damage warnings.
Data Source
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AI summary
A method for monitoring the health of propellers in an aircraft is provided. The method includes receiving a first propeller pitch angle of a first propeller of an aircraft; calculating a first residual pitch angle which is the difference between the first propeller pitch angle and a second propeller pitch angle; and comparing the first residual pitch angle to at least one threshold. The at least one threshold may include upper and lower thresholds. It is established that the health of the propeller may be impaired if the residual pitch angle is outside the at least one threshold, for example it exceeds the upper threshold or is below the lower threshold. If it is established that the health of the propeller may be impaired, an alert is made for inspection and maintenance to take place.