Cyclostationary Vibration Analysis for Speed-Variable Machinery Monitoring
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Solution Overview
Problem
Existing monitoring systems for mechanical systems with rotating members struggle to accurately detect faults due to variations in sensor positioning and orientation, leading to unreliable fault detection, especially during transient phases and operational fluctuations.
Innovation Solution
A method and device that analyze the cyclostationarity of vibratory signals from rotating mechanical systems by transforming temporal signals into angular signals, calculating cyclostationarity indicators using statistical hypothesis tests, and optimizing sensor positioning and orientation to ensure reliable fault detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional vibration monitoring methods are used, then the system can detect faults in mechanical systems, but the detection reliability deteriorates during transient phases and operational fluctuations due to sensor positioning variations
Solution Approach 1:
The patent transforms the vibration analysis from time-domain parameters to angular-domain parameters by synchronizing vibration signals with rotational position data. This parameter transformation allows the system to evaluate vibrations relative to the rotational angle rather than absolute time, making the measurements invariant to speed fluctuations and transient operations, thereby improving both reliability and precision during variable operating conditions
Solution Approach 2:
The patent applies preliminary signal processing by synchronizing the vibration signals with the rotational position before analysis. By pre-aligning the signals based on angular position, the system prepares the data in a form that is inherently robust to speed variations, enabling reliable fault detection without requiring perfect sensor positioning or stable operating conditions
2Reliability
If multiple sensors are deployed for comprehensive monitoring, then the coverage and detection capability improve, but the system complexity and cost increase
Solution Approach 1:
The patent makes the vibration analysis method universal by transforming it to the angular domain, which allows a single sensor to provide comprehensive monitoring information regardless of its specific positioning on the rotor. The angular synchronization approach enables one sensor to capture fault information from different sources (imbalance, misalignment, bearing defects) that would traditionally require multiple sensors positioned at specific locations, thereby reducing system complexity while maintaining or improving monitoring coverage
Data Source
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AI summary
The present invention relates to various methods, including a method for determining the cyclostationarity of a vibration signal emitted by a vibration sensor 20 arranged on a mechanical system 10, and enabling the calculation of a cyclostationarity indicator Iα. The present invention also relates to a method for arranging vibration sensors using the cyclostationarity determination method applied to the signals emitted for different positions and orientations of these vibration sensors. A position of a vibration sensor 20 is validated based on this cyclostationarity indicator Iα. Finally, the present invention relates to a method for monitoring a mechanical system 10 using the cyclostationarity determination method to determine the cyclostationarity of the vibration signals related to the mechanical system 10 before calculating the monitoring indicators for the mechanical system 10.