Prosthetic Knee Joint Dynamic Resistance Control

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Solution Overview

Problem

Existing orthotic and prosthetic knee joints lack dynamic adjustment of flexion and extension resistance to mimic natural gait patterns, leading to inadequate support and stability during various phases of movement.

Innovation Solution

A method that uses sensor data to calculate auxiliary variables, such as moments and forces, to adjust flexion and extension resistance dynamically, allowing for real-time adaptation of resistance levels based on the user's movement phase and environmental conditions, including temperature changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple sensors and mathematical operations are used to calculate auxiliary variables for dynamic resistance adjustment, then the adaptability and naturalness of gait pattern is improved, but the device complexity and computing effort increase

Engineering Contradiction:
Improveadaptability of resistance adjustmentVSAvoidcomplexity of sensor system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The control device performs multiple functions: it processes data from multiple sensors (bending angle, acceleration, inclination, force), calculates multiple auxiliary variables through mathematical operations, and dynamically adjusts both flexion and extension resistance. This multi-functional approach allows a single integrated system to handle complex gait analysis and resistance control, improving adaptability while managing device complexity through functional integration.

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

2Reliability

If dynamic adjustment of flexion and extension resistance is implemented based on sensor data, then the support and stability during movement phases is improved, but the device complexity increases

Engineering Contradiction:
Improvestability during movementVSAvoidcomplexity of control system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system continuously monitors gait phase and joint status through multiple sensors, processes this information to calculate auxiliary variables, and dynamically adjusts resistance levels based on the calculated values. This closed-loop feedback mechanism ensures stable and reliable support during different movement phases by constantly adapting resistance to the user's actual gait characteristics, while managing control complexity through systematic feedback processing.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If auxiliary variables are calculated from sensor data using mathematical operations, then the precision of resistance control is improved, but the computing effort increases

Engineering Contradiction:
Improveprecision of resistance controlVSAvoidcomputing effort
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system transforms raw sensor data into meaningful auxiliary variables through mathematical operations, changing the parameter representation from direct sensor readings to calculated gait characteristics. This parameter transformation enables precise resistance control by deriving auxiliary variables that directly reflect the user's gait phase and joint status, allowing accurate resistance adjustment while managing computing effort through efficient mathematical transformations.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2772232B1Method of controlling an orthotic or prosthetic joint of a lower extremity
Publication Date: 2017.04.26 OTTO BOCK HEALTHCARE PROD GMBH
  • EP2772232B1 patent drawingFigure 1
  • EP2772232B1 patent drawingFigure 2
  • EP2772232B1 patent drawingFigure 3

AI summary

The invention relates to a method for controlling an orthotic or prosthetic joint (4) of a lower extremity with a resistance device to which at least one actuator is assigned, via which the flexion and/or extension resistance (R) is changed depending on sensor data, wherein status information is provided via sensors during use of the joint (4), wherein the sensor data are determined by at least one device for detecting at least two moments, or two forces and one moment, and the sensor data of at least two of the determined quantities are linked together by a mathematical operation and thereby an auxiliary variable (a, b, c, d) is calculated which forms the basis for controlling the flexion and/or extension resistance (R), wherein the auxiliary variable (c) is a transverse force (Ft) exerted on a lower connecting part (2) from the quotient of the difference of two moments (M1,M2) and the distance (13) between the two devices is determined to determine the moments to each other.