Epicyclic Gear Train Monitoring Using Contact-Phase Wave Sampling
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Solution Overview
Problem
Existing monitoring systems for mechanical transmission devices in aircraft, particularly epicycloidal trains, face challenges in effectively detecting anomalies due to the complex arrangement of toothed wheels and the need for improved sampling methods.
Innovation Solution
A monitoring process for epicycloidal trains that involves acquiring mechanical wave data and rotation speed data, calculating the rotation speed of contact points between toothed wheels, and re-sampling the mechanical wave data in phase with the contact point's rotation to detect anomalies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional acoustic sensor monitoring is used for epicyclic gear trains, then the monitoring system can detect mechanical vibrations, but the complex arrangement of toothed wheels and temporal variations in rotation speeds make anomaly detection ineffective
Solution Approach 1:
The patent transforms the monitoring approach by changing the sampling parameter from uniform time intervals to phase-based intervals synchronized with the contact point rotation. This parameter transformation allows the system to account for temporal variations in rotation speeds of different toothed wheels, thereby improving anomaly detection precision despite the complex gear train arrangement
Solution Approach 2:
The patent introduces a contact point as an intermediary reference between the multiple toothed wheels (sun, planet, and ring gears). By synchronizing sampling to the phase of this contact point, the system mediates the temporal variations in rotation speeds of different components, enabling effective anomaly detection across the complex epicyclic structure
2Ease of operation
If uniform time-based sampling is used for mechanical wave data, then the data acquisition is simple, but the temporal variations in rotation speeds cause misalignment and reduce anomaly detection effectiveness
Solution Approach 1:
The patent implements periodic sampling synchronized to the rotational phase of the contact point between toothed wheels. Instead of uniform time-based sampling, the system performs mechanical wave measurements at regular phase intervals, creating a periodic sampling pattern that accounts for the rotational dynamics and improves anomaly detection precision while maintaining operational feasibility
3Adaptability or versatility
If the rotation speeds of toothed wheels vary over time, then the gear train can adapt to different operating conditions, but the temporal variations cause misalignment in mechanical wave data sampling
Solution Approach 1:
The patent employs dynamic sampling synchronization that adapts to varying rotation speeds in real-time. By continuously tracking the phase of the contact point and adjusting sampling intervals accordingly, the system maintains precise alignment between mechanical wave measurements and the actual gear train state, preserving measurement precision across different operating conditions
Data Source
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AI summary
Disclosed is a method for monitoring an epicyclic gear train of an aircraft, comprising the following steps: acquiring, at a predetermined sampling frequency, first values (5(ti)) of a signal formed by a progressive mechanical wave generated in the epicyclic gear train; measuring, at a plurality of successive instants, values (Vmes _r(tj)) of a speed of rotation of at least one of the toothed wheels of the gear train; calculating values (Vc(tj)) of a speed of rotation of a point of contact between two toothed wheels of the epicyclic gear train; determining second values (S(ç½ )) of the signal formed by a progressive mechanical wave generated in the epicyclic gear train, the second values being sampled depending on a phase of the point of contact and forming secondary mechanical wave data; and using the secondary mechanical wave data (S(ç½ )) to detect an anomaly related to the operation of the epicyclic gear train.