Artificial Knee Joint Rotational Resistance Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing artificial knee joints struggle to provide optimal rotational resistance control during different phases of walking, leading to inefficiencies and discomfort for users.

Innovation Solution

The artificial knee joint incorporates a thigh joint part, a lower leg part, a thigh part inclination angle acquisition unit, and a rotational resistance control unit that adjusts the rotational resistance of the knee shaft based on the inclination angle and walking phase.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the rotational resistance of the knee shaft is increased during the Stance phase to prevent the knee from bending under load, then stability is improved, but the ease of operation deteriorates because the user experiences difficulty in initiating the swing phase

Engineering Contradiction:
Improveknee stabilityVSAvoidease of operation
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The patent applies dynamics by making the rotational resistance of the knee shaft dynamically adjustable based on the detected walking phase. The rotational resistance is increased during the Stance phase to provide stability and decreased during the transition to Swing phase to facilitate easy operation. This dynamic adjustment resolves the contradiction between stability and ease of operation by adapting the resistance level to the specific phase of the walking cycle.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent uses feedback from the inclination angle acquisition unit that detects the thigh part's inclination angle to determine the walking phase. This feedback mechanism allows the rotational resistance control unit to automatically adjust the resistance level appropriately - high during Stance phase when the thigh is inclined rearward, and low during Swing phase when the thigh moves forward, thereby resolving the contradiction between stability and ease of operation.

Inventive Principle:
Principle #23Feedback

2Ease of operation

If the rotational resistance of the knee shaft is decreased during the Swing phase to allow knee bending and prevent the prosthetic limb from touching the ground, then the ease of operation is improved, but the stability deteriorates because the knee may become unstable under unexpected loads

Engineering Contradiction:
Improveease of operationVSAvoidknee stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent applies dynamics by making the rotational resistance of the knee shaft dynamically adjustable based on the detected walking phase. The rotational resistance is decreased during the Swing phase to provide ease of operation for knee bending while maintaining stability through phase-based control. This dynamic adjustment resolves the contradiction between ease of operation and stability by adapting the resistance level to the specific phase of the walking cycle.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent uses feedback from the inclination angle acquisition unit that detects the thigh part's inclination angle to determine the walking phase. This feedback mechanism allows the rotational resistance control unit to automatically adjust the resistance level appropriately - low during Swing phase when the thigh is inclined forward to enable easy operation, while maintaining stability through proper phase detection and control.

Inventive Principle:
Principle #23Feedback

3Device complexity

If a fixed rotational resistance is applied to the knee shaft throughout the walking cycle, then the device complexity is reduced, but the adaptability deteriorates because the knee joint cannot optimize performance for different walking phases

Engineering Contradiction:
Improvecontrol mechanism complexityVSAvoidadaptability to walking phases
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent uses feedback from the inclination angle acquisition unit that continuously monitors the thigh part's inclination angle to detect the walking phase. This feedback enables the rotational resistance control unit to automatically adapt the resistance level to different walking phases (Stance, Swing, etc.), providing high adaptability without requiring complex manual adjustment mechanisms. The system adapts automatically based on real-time detection of thigh inclination changes.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent implements self-service by enabling the knee joint to automatically adjust its own rotational resistance based on the detected walking phase through the inclination angle acquisition unit. The system serves itself by using the user's own movement (thigh inclination changes) as the trigger for resistance adjustment, eliminating the need for external control or complex mechanical mechanisms while achieving high adaptability to different walking phases.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4104800B1Artificial knee joint, method of controlling artificial knee joint, and program to control artificial knee joint
Publication Date: 2025.01.29 NABTESCO CORP
  • EP4104800B1 patent drawingFigure 1
  • EP4104800B1 patent drawingFigure 2
  • EP4104800B1 patent drawingFigure 3A~3B3C

AI summary

A prosthetic limb (10) includes: a socket (11) as a thigh part; a thigh joint part provided on a side of the socket (11); a lower leg part (21) coupled to the thigh joint part and provided to be rotatable around a knee shaft (23); a thigh part inclination angle acquisition unit that acquires an inclination angle Ψ formed by the socket (11) relative to a vertical line passing through the knee shaft (23); and a rotational resistance control unit (100) that weakens a rotational resistance of the knee shaft (23) in accordance with a transition from a positive inclination angle formed when the socket (11) is inclined rearward relative to the vertical line to a negative inclination angle formed when the socket (11) is inclined forward relative to the vertical line.