Behavior Task Phase Analysis for Caregiver Fatigue Attribution

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Solution Overview

Problem

Existing fatigue evaluation systems struggle to accurately identify the cause of fatigue on a detailed action phase basis, making it difficult to assess and mitigate the impact of specific tasks on a caregiver's health condition.

Innovation Solution

A behavior task evaluation system that utilizes environmental data, motion capture, and sensory data to analyze the transition of health conditions during habitual behavior tasks, identifying action phases with reduced efficiency and providing feedback for improvement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If fatigue degree evaluation systems measure objective and subjective fatigue degrees, then the test subject can recognize their fatigue state, but it is very difficult to judge a fatigue cause based on the relationship with specific tasks

Engineering Contradiction:
Improvefatigue degree measurementVSAvoidfatigue cause identification
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The behavior task is divided into multiple action phases (approach phase, execution phase, retreat phase) to segment the continuous task into discrete analyzable units. This segmentation allows the system to identify which specific phase causes fatigue, transforming the undifferentiated fatigue measurement into phase-specific cause identification.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system provides feedback by comparing active state data across multiple executions of the same behavior task, identifying phases where execution efficiency decreases. This feedback mechanism enables the system to pinpoint specific action phases that cause fatigue, converting general fatigue information into actionable cause-specific insights.

Inventive Principle:
Principle #23Feedback

2Ease of operation

If the psychosomatic state measuring apparatus measures physical condition only in quietly-resting-in-bed situation, then the measurement subject's load is reduced, but it is very difficult to judge to which action the chronic stress and acute stress are attributable

Engineering Contradiction:
Improvemeasurement subject loadVSAvoidstress cause attribution
Core Design Contradiction:
Ease of operationVSLoss of information

Solution Approach 1:

The system transitions from static measurement (only in resting state) to dynamic measurement (during actual behavior task execution). By measuring active state data during movement and task performance, the system captures physiological changes in real-time, enabling attribution of stress to specific action phases while the subject performs natural movements rather than remaining static.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system pre-divides behavior tasks into action phases and prepares measurement protocols for each phase before execution. This preliminary structuring allows the system to capture stress information at the right moments during task performance, enabling cause attribution without requiring the subject to enter artificial resting states.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If wearable motion assistance device is used to assist heavy muscular work, then care giver's burden is reduced, but care giver will still become fatigued if they perform nursing care work for long time

Engineering Contradiction:
Improvenursing care efficiencyVSAvoidcare giver working duration
Core Design Contradiction:
ProductivityVSDuration of action of moving object

Solution Approach 1:

The system continuously monitors active state data (heart rate, temperature, motion) during nursing care work and provides feedback on fatigue accumulation. By analyzing changes in execution efficiency across multiple task executions, the system identifies when fatigue begins to impair performance, enabling timely intervention before exhaustion occurs and extending safe working duration.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system establishes baseline active state data from initial task executions and uses this preliminary information to set fatigue thresholds. This preliminary action enables the system to predict when fatigue will impair performance, allowing proactive management of working duration and prevention of exhaustion before it occurs.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4033495B1Behavior task evaluation system and behavior task evaluation method
Publication Date: 2026.01.21 CYBERDYNE INC
  • EP4033495B1 patent drawingFigure 1
  • EP4033495B1 patent drawingFigure 2
  • EP4033495B1 patent drawingFigure 3

AI summary

When a subject executes a specified behavior task, an action phase in which its execution efficiency becomes equal to or lower than a specified level is accurately identified from the relation with a transition of the subject's health condition which is obtained by habitual repetition of the behavior task on the basis of a detection result of their own active state .