Segmented Exoskeleton Tibial Joint for Foot Rotation

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Solution Overview

Problem

Conventional exoskeletons that assist user movement limit freedom and cause fatigue due to the need for users to carry the structure, and they often restrict foot rotation and mobility, especially on uneven terrain.

Innovation Solution

The exoskeleton subassembly is designed with a tibial segment divided into two parts, allowing internal/external rotational movement through a joint between the knee and ankle, and additional joints for eversion/inversion, along with attachment mechanisms that allow flexible foot rotation and load distribution, enhancing comfort and mobility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the user carries the exoskeleton structure on their body, then the exoskeleton provides support and assistance, but the user's freedom of movement is limited and additional load and fatigue are generated

Engineering Contradiction:
Improveexoskeleton supportVSAvoiduser freedom of movement
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The tibial segment is divided into two separate pieces (first tibial piece and second tibial piece) connected by a first joint. This segmentation allows the exoskeleton to adapt to foot rotation movements while maintaining structural support, resolving the contradiction between providing reliable support and allowing user freedom of movement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first joint between the two tibial pieces enables dynamic rotation to accommodate internal/external foot rotation, while the second joint at the ankle allows dynamic adaptation to eversion/inversion movements. This dynamic design maintains support reliability while preserving user mobility and freedom of movement.

Inventive Principle:
Principle #15Dynamics

2Weight of moving object

If plates are placed under the user's feet to transfer exoskeleton mass to the ground, then the user is relieved of some load, but the user's feet are not in contact with the ground reducing comfort and mobility

Engineering Contradiction:
Improveuser carried loadVSAvoiduser comfort and mobility
Core Design Contradiction:
Weight of moving objectVSEase of operation

Solution Approach 1:

The ankle joint (second joint) provides dynamic rotation capability that allows the user's foot to remain in contact with the ground while the exoskeleton mass is transferred to the ground through the foot part. This resolves the contradiction by enabling both load transfer and ground contact for comfort and mobility.

Inventive Principle:
Principle #15Dynamics

3Weight of moving object

If the exoskeleton structure includes ground contact plates, then load transfer is enabled, but the user's mobility is reduced and foot rotation is restricted

Engineering Contradiction:
Improveexoskeleton mass transferVSAvoidfoot rotation capability
Core Design Contradiction:
Weight of moving objectVSAdaptability or versatility

Solution Approach 1:

The tibial segment is segmented into two pieces with a first joint between them, allowing internal/external rotation of the foot while maintaining ground contact capability for mass transfer.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The combination of the first joint (for internal/external rotation) and the second ankle joint (for eversion/inversion) creates a dynamic system that enables full foot rotation capability while maintaining ground contact for load transfer, resolving the contradiction between mass transfer and adaptability.

Inventive Principle:
Principle #15Dynamics

4Reliability

If the exoskeleton does not allow full foot rotation, then ground support is provided on stable terrain, but the structure does not provide support on sloping or uneven ground

Engineering Contradiction:
Improveground support stabilityVSAvoidterrain adaptability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The first joint between the tibial pieces and the second ankle joint create a dynamic system that adapts to various terrain conditions. The joints allow the exoskeleton to maintain ground support on stable terrain while adapting to sloping or uneven ground through foot rotation, resolving the contradiction between stability and terrain adaptability.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3562626B1Exoskeleton sub-assembly and exoskeleton structure including such a sub-assembly
Publication Date: 2021.02.03 SAFRAN ELECTRONICS & DEFENSE (FR)
  • EP3562626B1 patent drawingFigure 1
  • EP3562626B1 patent drawingFigure 2
  • EP3562626B1 patent drawingFigure 3

AI summary

The invention relates to an exoskeleton sub-assembly (30) comprising: - a leg part (32) to be attached to a leg of a user, and - a foot part (33) to be attached to a shoe of the user; the leg part (32) comprises a tibial segment (321) extending below the knee, along the tibia of the user, when the leg part (32) is attached to the leg, and the tibial segment (321) comprises a first component (325), a second component (326) connected to the foot part (33), and a first joint (327) connecting the second component (326) to the first component (325), the first joint (327) permitting a rotation of the second component (326) with respect to the first component (325) caused by an internal or external rotation of the user's foot with respect to the leg.