Motion Guide Lifespan Diagnosis Using Virtual Fatigue Segments

Solution Overview

Problem

Existing motion guidance devices face challenges in accurately diagnosing the lifespan of rolling surfaces due to localized fatigue, as strain gauges struggle to perceive fatigue across the entire rolling surface, making it difficult to predict lifespan effectively.

Innovation Solution

A lifespan diagnosis system that calculates stresses and counts occurrences for virtual segments of the rolling surface, using displacement data to determine a lifespan exhaustion ratio for each segment, improving diagnostic accuracy by analyzing localized fatigue.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a strain gauge is used to measure the actual load applied to the component, then the load measurement capability is improved, but the ability to perceive localized fatigue of the rolling surface deteriorates

Engineering Contradiction:

Improveload measurement capabilityVSAvoidlocalized fatigue detection precision

Core Design Contradiction:

ForceVSMeasurement precision

Solution Approach 1:

The rolling surface is divided into multiple virtual segments along the track direction. Stress calculations are performed separately for each segment based on displacement measurements, enabling localized fatigue assessment rather than providing only a global load measurement.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Displacement sensors serve as intermediaries to indirectly measure stress distribution. By measuring displacement at multiple positions and calculating stress from these displacement values, the system achieves localized stress measurement without directly attaching sensors to the rolling surface.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If the rolling surface is divided into virtual segments for localized stress calculation, then the lifespan diagnosis precision is improved, but the computational complexity increases

Engineering Contradiction:

Improvelifespan diagnosis precisionVSAvoidcomputational complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The rolling surface is divided into multiple virtual segments along the track direction. Stress calculations are performed separately for each segment based on displacement measurements, enabling localized fatigue assessment rather than providing only a global load measurement.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system changes from measuring only global load parameters to measuring and calculating local displacement and stress parameters for each segment. This parameter transformation enables precise localization of fatigue while the computational complexity is managed through efficient stress calculation methods.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If displacement measurements are used to calculate stress for each segment, then the lifespan prediction accuracy is improved, but the measurement system complexity increases

Engineering Contradiction:

Improvelifespan prediction accuracyVSAvoidmeasurement system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Displacement sensors serve as intermediaries to indirectly measure stress distribution. By measuring displacement at multiple positions and calculating stress from these displacement values, the system achieves localized stress measurement without directly attaching sensors to the rolling surface.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The displacement measurement system serves multiple functions: it measures both global position and local displacement for stress calculation. The same measurement infrastructure supports both motion control and lifespan diagnosis functions, reducing overall system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11371909B2Lifespan diagnosis device, method, non-transitory storage medium, and system for motion guidance device

Publication Date: 2022.06.28 THK CO LTD

AI summary

A lifespan diagnosis device for a motion guidance device including: a stress calculating means which calculates stresses during movement for each of virtual segments, the stresses during movement being stresses that occur in each segment during a movement of the moving member; a counting means which counts, for each of the segments, on the basis of the amount of displacement, the number of occurrences of the stresses during movement which repetitively occur with waving during a movement of the moving member along the track; and a diagnostic means which calculates, for each of the segments, a lifespan exhaustion ratio on the basis of magnitudes of the stresses during movement and the number of occurrences of the stresses during movement, and which diagnoses the lifespan of the motion guidance device on the basis of the calculated lifespan exhaustion ratios of the respective segments.