Lissajous Vibration Analysis for Rotating Device Abnormality Detection

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Solution Overview

Problem

Existing methods for determining abnormality in rotating devices using Lissajous waveform diagrams require time-consuming preparation of reference diagrams and manual comparison, making it difficult to detect unexpected abnormalities.

Innovation Solution

Generate a first Lissajous figure from vibration data and rotate it to create multiple figures, calculating the degree of difference between each figure to identify symmetry changes indicative of normal or abnormal states without pre-stored reference diagrams.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If reference Lissajous waveform diagrams are prepared in advance for each abnormality cause, then abnormality determination can be performed by comparison, but time and effort are required for preparation and unexpected abnormalities cannot be detected

Engineering Contradiction:

Improveabnormality detection capabilityVSAvoidtime for preparing reference diagrams

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system uses the object's own Lissajous waveform as a reference by rotating it to generate multiple versions. Instead of requiring external pre-prepared reference diagrams for each abnormality type, the method self-generates reference waveforms through rotational transformation, enabling detection of both expected and unexpected abnormalities without time-consuming preparation.

Inventive Principle:

Principle #25Self-service

2Measurement precision

If multiple reference Lissajous waveform diagrams are prepared for different abnormality causes, then abnormality cause can be determined by comparison, but the method is complex and cannot handle unexpected abnormalities

Engineering Contradiction:

Improveabnormality cause determination accuracyVSAvoidnumber of reference diagrams required

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The method dynamically generates reference Lissajous waveform diagrams by rotating the original waveform by various angles (0°, 45°, 90°, 135°, etc.) to create multiple versions. This dynamic approach replaces the need for storing numerous static reference diagrams for different abnormality causes, reducing complexity while maintaining the ability to determine abnormality causes through comparison.

Inventive Principle:

Principle #15Dynamics

3Loss of information

If Lissajous waveform diagrams are compared manually to determine abnormality causes, then diagnostic information can be obtained, but the process requires significant time and effort

Engineering Contradiction:

Improvediagnostic information completenessVSAvoidtime for comparing waveforms

Core Design Contradiction:

Loss of informationVSLoss of time

Solution Approach 1:

The system automatically compares the measured Lissajous waveform with multiple rotated reference waveforms and determines the degree of difference, providing objective feedback on abnormality presence and cause. This automated feedback mechanism eliminates manual comparison time while preserving complete diagnostic information through systematic evaluation of waveform differences.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS20250369827A1Signal Processing Method, Signal Processing Apparatus, Signal Processing System, And Non-Transitory Computer-Readable Storage Medium Storing Signal Processing Program

Publication Date: 2025.12.04 SEIKO EPSON CORP

AI summary

A signal processing method includes generating a first Lissajous figure based on a physical quantity generated by a vibration of an object, generating second to N-th Lissajous figures by rotating the first Lissajous figure, N being an integer of 2 or more, and calculating an (i−1)-th degree of difference as a degree of difference between the first Lissajous figure and the i-th Lissajous figure with respect to each integer i from 2 to N.