Care Robot Trajectory Control for Comfortable Patient Transitions

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Solution Overview

Problem

Existing care robots make care receivers uncomfortable during standing-upright and sitting motions due to uncomfortable trajectories.

Innovation Solution

A care robot with a holding section that supports the upper body, using stored trajectory data to guide the care receiver along comfortable standing-upright and sitting trajectories, similar to those of a healthy person, and adjusts velocity and angle to simulate natural movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the care robot assists standing-upright and sitting motions using conventional trajectories, then the assistance function is provided, but the care receiver feels uncomfortable during the motions

Engineering Contradiction:
Improvecomfortability of motion trajectoryVSAvoidnaturalness of movement
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system pre-stores multiple types of trajectory data (reference trajectory, training trajectory, and natural trajectory) in advance. When assisting the care receiver, the control device selects and executes the appropriate pre-stored trajectory based on the current mode, eliminating the need for real-time trajectory calculation and ensuring comfortable, natural movement from the start

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes trajectory parameters by selecting different pre-stored trajectory data types. By switching between reference trajectory data, training trajectory data, and natural trajectory data, the system adapts the motion characteristics to match different assistance modes, providing both comfort and naturalness in movement

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If the care robot uses a fixed standing-upright trajectory, then the control is simplified, but the care receiver cannot train specific body parts

Engineering Contradiction:
Improvesimplicity of control systemVSAvoidtraining capability for body parts
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The system dynamically switches between different pre-stored trajectory data types based on the assistance mode. The control device changes the trajectory characteristics in real-time by selecting appropriate stored data, enabling both simplified control architecture and adaptable training capabilities for different body parts

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control device performs multiple functions by selecting from universal pre-stored trajectory data. The same control system handles both simple assistance (using reference trajectory) and specialized training (using training trajectory with adjusted velocity), eliminating the need for separate control systems

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

3Productivity

If the care robot moves the care receiver quickly between positions, then the assistance efficiency is improved, but the movement becomes unnatural and uncomfortable

Engineering Contradiction:
Improveefficiency of position transitionVSAvoidnaturalness of movement
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The system applies periodic velocity adjustment by changing the velocity of movement according to the specific phase of the trajectory. During critical phases like standing-upright and sitting motions, the velocity is reduced to ensure comfort and naturalness, while maintaining overall assistance efficiency through optimized velocity profiles stored in the trajectory data

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP2954882B1Patient-care robot
Publication Date: 2023.09.06 FUJI CORP
  • EP2954882B1 patent drawingFigure 1
  • EP2954882B1 patent drawingFigure 2~3
  • EP2954882B1 patent drawingFigure 4a

AI summary

Provided is a care robot that assists a standing-upright motion or a sitting motion of a care receiver without making the care receiver uncomfortable. In a care robot 20, a standing-upright trajectory Tas1, along which a movement control portion Ps of a care receiver M1 moves, is set such that a center G of gravity of the care receiver M1 is present in a range A of the soles of both feet between a point in time early after the start of a standing-upright motion and an end time point of the standing-upright motion of the care receiver M1, and a sitting trajectory Tbs1, which is different from the standing-upright trajectory Tas1, and along which the movement control portion Ps of the care receiver M1 moves, is set such that the center G of gravity of the care receiver M1 is present out of the range A of the soles of both feet from a point in time early after the start of a sitting motion of the care receiver M1, and moves toward a predetermined sitting position of the care receiver M1.