Weight-Supported Walking Assist With Knee Flexion Phase Control

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Solution Overview

Problem

Existing treatments for knee osteoarthritis, such as surgeries, pose high risks and burdens, and there is a need for a non-invasive method to reduce the weight burden on the knee joint during walking to aid in the regenerative healing process.

Innovation Solution

A weight-supported walking assist apparatus with a seat unit, thigh and lower leg frames, hip and knee joint connectors, and a control system that adjusts the bending of the knee joint to a specified range and provides motive power based on biosignals and ground reaction forces to reduce the load on the knee joint during walking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If surgery is conducted to treat knee osteoarthritis, then the knee joint can be repaired or replaced, but the patient faces high risks, complications, and high mental and physical burdens

Engineering Contradiction:
Improvetreatment effectivenessVSAvoidsurgical risks and burdens
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical surgical intervention with a non-invasive regenerative medicine approach combined with a mechanical assistance device. The wearable apparatus provides external support and controlled motion assistance to promote natural healing without surgical invasion, thereby eliminating surgical risks while maintaining treatment effectiveness.

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

Solution Approach 2:

The wearable apparatus acts as an intermediary between the patient's body and the treatment process. It provides external support and controlled motion assistance, mediating the healing process by reducing knee joint burden and enabling controlled movement that promotes regenerative healing without direct surgical intervention.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the patient walks with full body weight on the knee joint to promote natural movement, then walking function is maintained, but the weight burden on the knee joint part increases and hinders regenerative healing

Engineering Contradiction:
Improvewalking functionVSAvoidweight burden on knee joint
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The apparatus provides counterbalancing support through its mechanical structure and actuators, effectively reducing the gravitational force (body weight) acting on the knee joint. The seat unit and frame structure bear part of the body weight, while the actuators provide active force compensation, allowing the knee joint to move with significantly reduced load during the healing process.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The system dynamically changes the load parameter on the knee joint by adjusting the support force provided by the actuators. During different phases of the walking cycle, the apparatus modifies the amount of weight bearing allowed, reducing the force parameter to protect the healing joint while still enabling functional movement.

Inventive Principle:
Principle #35Parameter changes

3Force

If the knee joint is completely immobilized to protect it during healing, then weight burden is reduced, but the patient loses walking ability and muscle atrophy occurs

Engineering Contradiction:
Improveweight burden reductionVSAvoidwalking ability
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

The apparatus transitions from static immobilization to dynamic controlled motion. The actuators provide active assistance that adapts to the patient's movement intentions, enabling controlled knee joint motion during walking while maintaining protective load reduction. This dynamic approach preserves muscle function and walking ability while protecting the healing joint.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses biosignal detection and gait analysis to provide feedback-controlled motion assistance. Sensors detect the patient's movement intentions and gait phase, and the control system adjusts the actuator output accordingly, enabling natural-looking walking motion while maintaining protective load management on the healing knee joint.

Inventive Principle:
Principle #23Feedback

4Device complexity

If a simple passive support device is used to reduce knee joint burden, then the device complexity is low, but it cannot provide adaptive motion assistance or control the knee joint bending angle

Engineering Contradiction:
Improvedevice structureVSAvoidmotion control capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The apparatus employs self-service through automatic gait phase detection and adaptive control. The system autonomously detects the walking phase through sensors and automatically adjusts the actuator output and lock mechanism operation without requiring manual control, providing adaptive motion assistance that responds to the patient's natural gait patterns while maintaining relatively simple operation.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4406525B1Body weight supporting-type walking assisting apparatus and method for controlling same
Publication Date: 2026.01.21 CYBERDYNE INC
  • EP4406525B1 patent drawingFigure 1
  • EP4406525B1 patent drawingFigure 2
  • EP4406525B1 patent drawingFigure 3(A)~3(B)

AI summary

When a wearer who wears a weight-supported walking assist apparatus performs walking motions in a state with their buttocks supported by a seat unit, bending of the wearer's knee joint part is limited to a specified range upon a transition from a swing phase to a stance phase; and on the other hand, upon a transition from the stance phase to the swing phase, the wearer's knee joint part can bend or extend and, at the same time, motive power is given according to the wearer's intention.