H-Shaped Cable-Driven Mechanism for Upper Body Rehabilitation

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Solution Overview

Problem

Current robotic devices for upper body rehabilitation, particularly for elbows and shoulders, face limitations such as high costs, complexity, and lack of portability, making them inaccessible to most stroke survivors, especially those with mild impairments, and often require highly trained personnel for safe operation.

Innovation Solution

A rehabilitation patient-robot interaction apparatus featuring a H-shaped cable-driven mechanism with two motors, a six-degree of freedom force/torque sensor, and a manipulandum for independent movement along x and y axes, providing low inertia and homogeneous impedance, which is cost-effective, portable, and easy to operate, allowing for patient-robot interaction in various settings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional robotic devices are used for upper body rehabilitation, then rehabilitation effectiveness is improved, but cost and device complexity increase significantly

Engineering Contradiction:
Improverehabilitation effectivenessVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The robotic device is segmented into modular components: a base unit with motors, a cable-driven manipulator with multiple carriages, and a control system. This segmentation allows each component to be optimized independently and simplifies manufacturing and maintenance while maintaining rehabilitation effectiveness

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Cables serve as intermediaries to transmit force from the motors to the manipulator end-effector. This indirect force transmission mechanism reduces the complexity of direct mechanical coupling while maintaining precise control and force application for rehabilitation therapy

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If conventional robotic devices are used for upper body rehabilitation, then rehabilitation effectiveness is improved, but portability deteriorates

Engineering Contradiction:
Improverehabilitation effectivenessVSAvoidportability
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The device replaces heavy rigid mechanical linkages with a cable-driven system. The cables transmit forces while allowing the manipulator to be lightweight and portable, yet still provide sufficient force for rehabilitation therapy through the cable tension mechanism

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

3Reliability

If conventional robotic devices are used for upper body rehabilitation, then rehabilitation effectiveness is improved, but ease of operation deteriorates

Engineering Contradiction:
Improverehabilitation effectivenessVSAvoidease of operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The device incorporates automatic cable tensioning mechanisms and sensor-based force control that self-regulate during operation. The system automatically adjusts to patient movements and provides appropriate resistance or assistance without requiring constant manual calibration by trained personnel

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

Force sensors and position encoders provide real-time feedback to the control system, which automatically adjusts motor commands to maintain appropriate interaction forces. This closed-loop control simplifies operation by eliminating the need for manual force calibration by trained operators

Inventive Principle:
Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The apparatus enables effective and accessible rehabilitation by providing a low-cost, portable, and user-friendly solution for upper body movement therapy, complementing existing robotic therapies and allowing for early discharge and continuous monitoring of patients, while reducing the need for highly trained personnel.

Implementation Method 1

a H-shaped cable-driven mechanism with two motors, two driving pulleys coupled to the two motors respectively

Methodology Applied
Scientific EffectPulley: Pulley

Data Source

PatentEP2928568B1An apparatus for upper body movement
Publication Date: 2019.06.19 NANYANG TECH UNIV
  • EP2928568B1 patent drawingFigure 1~3(c)
  • EP2928568B1 patent drawingFigure 4~6
  • EP2928568B1 patent drawingFigure 7(a)~8

AI summary

There is provided an apparatus for upper body movement. The apparatus comprises a H-shaped cable-driven mechanism; two motors for driving the H-shaped cable-driven mechanism; and a manipulandum coupled to the H-shaped cable-driven mechanism for independent movement along x and y axes.