Gearbox Rotational Speed Estimation via Vibration Signal Vertices
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Solution Overview
Problem
Existing methods for estimating the rotational speed of a gear box without an encoder are inefficient due to issues with signal demodulation in multi-component mechanical systems, overlapping frequencies, and noise, which lead to inaccurate and unreliable speed profiles.
Innovation Solution
A speed estimation apparatus and method that converts a vibration signal from a gear box into time-frequency representation, selects vertices based on energy values, and generates speed information by connecting vertices, thereby overcoming the limitations of encoderless signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If demodulation technique is used to extract encoderless vibration data, then vibration data can be extracted without encoder, but performance deteriorates when harmonics are detected in multiple directions and overlapping frequencies exist due to noise
Solution Approach 1:
The patent segments the vibration signal into multiple frequency bands using bandpass filters before demodulation. This segmentation allows the demodulation technique to process specific frequency components separately, reducing interference from harmonics and overlapping frequencies in other bands, thereby improving measurement precision while maintaining encoderless operation
Solution Approach 2:
The patent applies local quality by focusing the demodulation process on specific frequency regions of interest. By identifying and isolating the fundamental frequency component through spectral analysis and then applying demodulation only to that specific band, the method improves accuracy by avoiding the noise and harmonics present in other frequency ranges
2Measurement precision
If additional signal filtering technique is added to improve demodulation performance, then vibration data accuracy improves, but device complexity increases
Solution Approach 1:
The patent performs preliminary spectral analysis and identifies the fundamental frequency component before applying the demodulation technique. This preliminary action allows the system to target the demodulation process at the correct frequency band, reducing or eliminating the need for additional complex filtering stages while maintaining high measurement precision
3Adaptability or versatility
If ridge extraction technique is used to identify frequency variability, then change trend of vibration data can be identified, but physical information needs to be recognized in advance and overlapping between ridges and noise problems occur
Solution Approach 1:
The patent changes the approach by using bandpass filtering to separate frequency components before applying demodulation. This parameter change in the signal processing workflow allows the system to identify frequency variability without requiring advance physical information recognition, while the filtering step prevents overlapping between ridges and noise, improving measurement precision
4Ease of operation
If velocity profile is acquired from encoder or IMU to analyze vibration signal, then speed data can be obtained, but errors occur due to time delay between vibration sensors and frequency shifting during signal transmission
Solution Approach 1:
The patent applies self-service by extracting the speed information directly from the vibration signal itself through demodulation, rather than relying on separate encoder or IMU measurements. This self-contained approach eliminates time delays and frequency shifting issues that occur when synchronizing multiple sensors, as the speed data is derived intrinsically from the vibration characteristics
Data Source
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AI summary
According to one embodiment of the present disclosure, a speed estimation apparatus may include a converter configured to convert a vibration signal acquired from a gear box into time-frequency representation (TFR), and a generator configured to select a first vertex at a first unit time, based on an energy value of each vertex in the TFR, and to generate information on an operating speed of a machine including the gear box by connecting the first vertex to a second vertex located at a second unit time.