Robot Drive Residual Life Prediction From Servo Current Trends

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Solution Overview

Problem

Conventional methods struggle to accurately predict the residual life of a robot drive system, making it difficult to plan maintenance schedules and perform timely maintenance, leading to potential robot breakdowns and production line stoppages.

Innovation Solution

A robot maintenance assist device that acquires data from servo motors, diagnoses future trends using a tendency diagnosis unit, and determines residual life by analyzing current command values, enabling accurate prediction and timely maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If residual life prediction is based on design life and operation time, then maintenance planning becomes simpler, but prediction accuracy deteriorates due to differences between assumed and actual operating conditions

Engineering Contradiction:
Improvemaintenance planning complexityVSAvoidresidual life prediction accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent changes the parameters used for residual life prediction from static design life and operation time to dynamic parameters including actual operating conditions, vibration data, temperature, and load patterns. This allows the prediction system to adapt to real-world variations and maintain accuracy across different operating scenarios.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces simple time-based mechanical counting with advanced diagnostic systems that use sensors, data acquisition units, and analysis algorithms to monitor actual component conditions. This substitution enables accurate prediction by replacing crude mechanical metrics with sophisticated electronic monitoring and analysis.

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

2Ease of operation

If maintenance is performed based on current data only, then immediate maintenance decisions can be made, but future maintenance timing cannot be specified

Engineering Contradiction:
Improvemaintenance decision makingVSAvoidmaintenance scheduling flexibility
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent performs preliminary analysis of current component conditions and establishes degradation trends before failure occurs. By analyzing historical data and current state, the system predicts future maintenance needs in advance, allowing maintenance teams to prepare and schedule interventions proactively rather than reactively.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism where actual component performance data is continuously monitored, compared against predicted degradation models, and used to update maintenance predictions. This closed-loop system refines accuracy over time and provides ongoing guidance for optimal maintenance timing.

Inventive Principle:
Principle #23Feedback

3Productivity

If robot breakdown is allowed to occur, then continuous production is maintained, but production line stops and productivity declines

Engineering Contradiction:
Improvecontinuous productionVSAvoidrobot operational reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary anti-action by predicting component failures before they occur and scheduling maintenance interventions in advance. This preventive approach counteracts potential breakdowns before they can disrupt production, maintaining both productivity and reliability by eliminating the risk of unexpected failures.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The patent creates a cushion of predicted residual life for critical components, allowing maintenance to be scheduled during planned downtime rather than forcing unexpected production stops. This cushioning effect protects the production system from the harmful impact of sudden failures.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP3235611B1Robot maintenance assist device and method
Publication Date: 2023.03.22 KAWASAKI JUKOGYO KK
  • EP3235611B1 patent drawingFigure 1
  • EP3235611B1 patent drawingFigure 2~4
  • EP3235611B1 patent drawingFigure 5

AI summary

This device includes an acquired data storing unit (4) for storing acquired data about a current command value of a servo motor configuring a robot drive system (R1); a tendency diagnosis unit (5) for diagnosing a future changing tendency of the current command value based on the data of the current command value stored in the acquired data storing unit (4); and a life determining unit (6) for determining a term until the current command value reaches a previously set value based on the future changing tendency of the current command value acquired by the tendency diagnosis unit (5). Thus, a residual life of the robot drive system can be accurately predicted.