Prosthetic Joint Resistance Control for Overheating Prevention

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Solution Overview

Problem

Artificial orthotic and prosthetic joints with resistance devices face overheating issues due to high energy dissipation, leading to potential damage and altered resistance behavior, which can compromise their functionality and safety.

Innovation Solution

A method and device that adjust flexion and extension resistance based on temperature measurements to prevent overheating, by increasing resistance during stance phase or reducing it during swing phase, allowing the joint to cool down and operate within safe parameters, while also providing a warning signal when critical temperatures are reached.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high flexion resistance is provided during stance phase to support body weight and prevent buckling, then joint stability and safety are improved, but energy dissipation increases causing overheating and potential damage to components

Engineering Contradiction:
Improvejoint stabilityVSAvoidenergy dissipation
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The resistance device dynamically adjusts its resistance characteristics based on real-time temperature monitoring. During stance phase, when high resistance is needed for stability, the system monitors temperature and reduces resistance when thermal thresholds are approached, preventing overheating while maintaining joint support functionality

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the resistance parameter as a function of temperature. By monitoring temperature and adjusting resistance levels accordingly, the device prevents excessive energy dissipation and overheating while maintaining adequate support during normal operation

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If resistance is increased to prevent joint buckling and support body weight, then joint safety is improved, but temperature increases leading to altered resistance behavior and potential failure

Engineering Contradiction:
Improvejoint buckling preventionVSAvoidresistance device temperature
Core Design Contradiction:
Object-affected harmful factorsVSTemperature

Solution Approach 1:

The system implements closed-loop temperature monitoring and resistance adjustment. Temperature sensors continuously monitor the resistance device, and when thermal thresholds are approached, the control system automatically adjusts resistance levels to prevent overheating, ensuring safe operation while maintaining joint support

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system proactively monitors temperature and preemptively reduces resistance before critical overheating occurs. By detecting temperature trends and adjusting resistance in advance, the system prevents thermal damage and maintains reliable joint support

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

3Ease of operation

If high resistance is maintained during swing phase to control leg swinging, then joint control is improved, but excessive heating occurs compromising device functionality

Engineering Contradiction:
Improveleg swing controlVSAvoiddevice functionality
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The resistance device dynamically adapts its characteristics during swing phase based on temperature conditions. When thermal thresholds are approached, the system reduces resistance to minimize heating while maintaining adequate leg swing control, preventing device failure

Inventive Principle:
Principle #15Dynamics

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

This approach reduces energy dissipation, prevents overheating, and maintains consistent joint performance by adapting resistance levels in response to temperature changes, ensuring the joint operates within safe limits and reduces the risk of failure or injury.

Implementation Method 1

the resistance device brakes the forward movement of the lower leg shaft or the lower leg splint

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

DE 10 2006 021 802 A1 describes a control of a passive prosthetic knee joint with adjustable damping in the flexion direction

Methodology Applied
Scientific EffectViscous damping: Viscous Damping

Implementation Method 3

the resistance as a function of a measured temperature or is changed by a measured temperature signal

Methodology Applied
Scientific EffectTemperature sensing: Thermocouple

Data Source

PatentEP2498730B1Method and device for controlling an artificial orthotic or prosthetic joint
Publication Date: 2014.02.26 OTTO BOCK HEALTHCARE PROD GMBH
  • EP2498730B1 patent drawingFigure 1~2
  • EP2498730B1 patent drawingFigure 3
  • EP2498730B1 patent drawingFigure 4

AI summary

The invention relates to a method and device for controlling an artificial orthotic or prosthetic joint with a resistance device to which at least one actuator is associated, via which the bending and/or stretching resistance is changed depending on sensor data. According to the invention, the resistance is adjusted depending on at least one measured temperature signal.