Servomotor Insulation Resistance Estimation Using Machine Learning

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Solution Overview

Problem

Conventional motor insulation deterioration diagnosis methods lack accuracy in estimating the insulation resistance of servomotors.

Innovation Solution

A machine learning device and method that generates a learning model using training data including initial and final insulation resistance, and time-series data of servomotor conditions, enabling the estimation of future insulation resistance through supervised learning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional motor insulation deterioration diagnosis methods are used, then the diagnosis can be performed, but the accuracy of insulation resistance estimation is insufficient

Engineering Contradiction:
Improveinsulation resistance estimation accuracyVSAvoiddiagnosis reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent transforms the insulation resistance estimation problem from a direct measurement task to a predictive task by changing the parameters used for estimation. Instead of relying on single-point measurements, the system uses multiple parameters including initial insulation resistance, operating hours, temperature history, humidity, and load conditions to predict future insulation resistance values. This parameter transformation enables more accurate and reliable estimation of motor insulation deterioration.

Inventive Principle:
Principle #35Parameter changes

2Loss of information

If simple insulation resistance measurement is performed, then the measurement process is simple, but the predictive capability for future insulation resistance is insufficient

Engineering Contradiction:
Improveinformation about future insulation resistanceVSAvoidmeasurement system complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by collecting and storing various operational parameters (temperature, humidity, load conditions, operating hours) during the motor's operation phase. This preliminary data collection enables the system to predict future insulation resistance values before actual deterioration occurs, providing advance warning for maintenance planning without requiring complex real-time monitoring during critical periods.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces direct mechanical/electrical measurement systems with an information processing and prediction system. Instead of continuously measuring insulation resistance through complex electrical tests, the system substitutes this with a prediction model that processes operational data (temperature, humidity, load patterns) to estimate future insulation resistance, thereby reducing measurement complexity while improving predictive capability.

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

3Measurement precision

If insulation resistance is measured at multiple time points, then more data is available, but the time and resources required increase

Engineering Contradiction:
Improveinsulation resistance data accuracyVSAvoidmeasurement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent creates a virtual copy of the insulation resistance measurement process through predictive modeling. Instead of performing actual repeated measurements over time, the system copies the essential relationships between operational conditions and insulation deterioration by training a prediction model on initial measurement data and operational parameters. This model then generates predicted insulation resistance values at future time points without requiring physical re-measurement, saving time and resources while maintaining data accuracy.

Inventive Principle:
Principle #26Copying

Data Source

PatentUS11928408B2Machine learning device, learning model generating method, insulation resistance estimating device, and control device
Publication Date: 2024.03.12 FANUC LTD
  • US11928408B2 patent drawing
  • US11928408B2 patent drawing
  • US11928408B2 patent drawing

AI summary

A machine learning device includes: a training data acquisition unit configured to acquire multiple pieces of training data each including insulation resistances of a servomotor at the beginning and the end of a certain period and time-series data indicating conditions of the servomotor in the certain period; and a learning model generating unit configured to perform a supervised learning using the training data to thereby generate a learning model.