Elevator Encoder Fault Detection for Bearing Frequency Analysis

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Solution Overview

Problem

Existing elevator power equipment fault detection methods are inadequate in accurately and efficiently identifying potential failures, particularly in bearings, which can impact safety and operation efficiency.

Innovation Solution

A fault detection method and device that utilizes existing encoder data to acquire running speed and acceleration signals, converts them into frequency-domain data, and compares peak frequencies with characteristic frequencies to detect equipment faults, optionally using multiple speed conditions and enhanced encoder settings for improved accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If vibration sensors are specially configured to monitor bearing performance, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvebearing fault detection accuracyVSAvoidsensor configuration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The encoder, originally designed for speed measurement, is utilized to provide vibration signal data for bearing fault detection. The system performs self-diagnosis by leveraging its own existing sensors rather than requiring separate dedicated vibration sensors, thus avoiding increased device complexity while maintaining measurement precision

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The encoder serves multiple functions: speed measurement and vibration signal acquisition for bearing monitoring. By making the encoder multi-functional, the patent eliminates the need for separate vibration sensors, resolving the contradiction between measurement precision and device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If multiple sensors are added for comprehensive monitoring, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvefault detection reliabilityVSAvoidsensor system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The encoder is designed to serve multiple monitoring functions simultaneously - speed measurement and vibration analysis - thereby improving reliability through comprehensive monitoring without adding separate sensor systems

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines speed measurement and vibration monitoring functions into a single encoder system, merging what would traditionally require separate sensors into one integrated component, thus improving reliability while avoiding increased complexity

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If additional vibration sensors are installed, then measurement precision is improved, but loss of substance increases

Engineering Contradiction:
Improvefault detection accuracyVSAvoidsystem cost
Core Design Contradiction:
Measurement precisionVSLoss of substance

Solution Approach 1:

The system uses its own encoder for self-diagnosis purposes, eliminating the need to purchase and install additional vibration sensors, thereby improving measurement precision without incurring additional material costs

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent utilizes existing inexpensive encoder components rather than investing in expensive dedicated vibration sensing equipment, achieving cost-effective fault detection by repurposing available resources

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Device complexity

If existing encoder data is utilized for fault detection, then device complexity is reduced, but measurement precision may worsen

Engineering Contradiction:
Improvesensor system simplicityVSAvoidfault detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies signal processing techniques (Fast Fourier Transform) to convert encoder speed data into vibration frequency domain data, substituting complex mechanical vibration sensing with computational analysis of existing electrical signals, thereby maintaining precision while reducing complexity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent transforms the encoder output from time-domain speed data to frequency-domain vibration data through mathematical transformation, changing the parameter representation to enable accurate bearing fault detection using existing hardware

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables timely, reliable, and cost-effective fault detection in elevator power equipment, reducing maintenance costs and enhancing safety and efficiency by leveraging existing system components without additional sensors.

Implementation Method 1

the running speed data of the actuator is acquired through an encoder associated with the actuator

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the frequency-domain signal data of the acceleration is obtained by conversion according to the time-domain signal data; the time-domain signal data is obtained by performing differential calculation according to the target data, and/or the frequency-domain signal data is obtained by performing Fast Fourier Transform according to the time-domain signal data

Methodology Applied
Scientific EffectFast Fourier Transform:

Data Source

PatentEP4242156B1Fault detection method and device for elevator power equipment and elevator system
Publication Date: 2025.11.12 OTIS ELEVATOR CO
  • EP4242156B1 patent drawingFigure 1
  • EP4242156B1 patent drawingFigure 2~3
  • EP4242156B1 patent drawingFigure 4~5

AI summary

A fault detection method and device for elevator power equipment and an elevator system are disclosed. The method comprises steps of: acquiring running speed data of an actuator in the elevator power equipment, and using the corresponding running speed data when the elevator is at a first speed and within a preset duration as target data; obtaining time-domain signal data of acceleration by calculation according to the target data, obtaining frequency-domain signal data of acceleration by conversion according to the time-domain signal data; comparing peak frequencies that form waveform peaks in the frequency-domain signal data with characteristic frequencies of the elevator power equipment, and determining the elevator power equipment to be faulty when at least one first frequency is detected in the peak frequencies, wherein the first frequency matches one of the characteristic frequencies and the amplitude thereof exceeds a preset threshold. By adopting the disclosure, a fault of elevator power equipment can be detected and discovered in time, on-site maintenance cost can be reduced, and safe operation of elevator can be guaranteed.