Modular Limb Joint With Torque Sensing Torsion Member

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Solution Overview

Problem

Current prosthetic and robotic limbs lack the ability to control joints effectively, particularly in prosthetic arms, which are not fully articulated and cannot replicate the complex movements of a human arm, and require complex wiring and mechanical connections that are not versatile for multiple joints, lacking torque and pressure sensing capabilities.

Innovation Solution

A modular limb joint assembly with a male and female connector system that provides a resilient, releasable connection with integral torque sensing, using strain gages and a torsion member to reduce torsional stiffness and allow for weather-sealed electrical connections, enabling robust mechanical and electrical attachment between limb segments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If custom bolted and screwed mechanical connections are used for each joint, then the connection strength is improved, but the device complexity increases and versatility decreases

Engineering Contradiction:
Improveconnection strengthVSAvoidconnection complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The connector is divided into separate male and female components with distinct functional elements (load bearing projection, socket, locking member, torsion member) that can be independently manufactured and assembled, simplifying production while maintaining connection strength

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connector design integrates multiple functions into a single standardized interface: mechanical load bearing, electrical connection, weather sealing, and torque sensing, allowing the same connector to be used across multiple joint types in both prosthetic and robotic applications

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

2Reliability

If complex wiring harnesses with bulky electrical connectors are used, then the electrical connection reliability is improved, but the device complexity increases and ease of operation worsens

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidwiring complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The electrical connector is merged with the mechanical connector into a single integrated assembly, where electrical contacts are positioned within the connector body itself, eliminating the need for separate wiring harnesses and bulky external connectors

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The same connector interface simultaneously provides both mechanical attachment and electrical connection functions, creating a universal interface that simplifies assembly operations across different joint configurations

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

3Stability of the object's composition

If rigid mechanical connections are used, then the structural stability is improved, but the ability to sense torque and provide bio-feedback decreases

Engineering Contradiction:
Improvestructural stabilityVSAvoidtorque sensing capability
Core Design Contradiction:
Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

A torsion member made of resilient material is introduced as an intermediary element between the load bearing projection and the connector body, allowing the rigid structural components to remain stable while the resilient torsion member deforms elastically under torque to enable precise torque sensing through strain gages

Inventive Principle:
Principle #24Intermediary (Mediator)

4Ease of operation

If modular connectors are used for easy attachment and detachment, then the ease of operation is improved, but the connection strength and reliability may worsen

Engineering Contradiction:
Improveattachment and detachment easeVSAvoidconnection strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The locking member is designed to automatically engage with the load bearing projection when the connector is assembled, providing immediate mechanical interlocking and strength without requiring additional fastening operations, while still allowing simple manual release for detachment

Inventive Principle:
Principle #10Preliminary action

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

Enables precise control of limb motion, prevents damage by sensing torque and load, and allows for bio-feedback control, enhancing the stability and functionality of prosthetic and robotic limbs by providing a modular, easily attachable and detachable system with improved mechanical and electrical interfaces.

Implementation Method 1

a torsion member made of a resilient material for reducing a torsional stiffness of the joint assembly

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a toothed outer periphery for engaging knurling formed on housing of a male connector assembly of the male connector when the connector includes the torsion member

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2509541B1Modular limb segment connector
Publication Date: 2015.03.25 HDT EXPEDITIONARY SYSTEMS INC
  • EP2509541B1 patent drawingFigure 1A~1B
  • EP2509541B1 patent drawingFigure 2
  • EP2509541B1 patent drawingFigure 3A

AI summary

A joint assembly for releasably securing a first and a second segment of an associated modular limb is provided. The joint assembly includes a male connector including a base and a load bearing blade secured to the base of the male connector protruding therefrom. The male connector is adapted to be secured to one of the first and second segments of the associated modular limb. A female connector is provided and includes a base and a load bearing socket secured to the base of the female connector. The socket is configured to selectively receive the blade of the male connector. The female connector is adapted to be secured to the other of the first and second segments of the associated modular lim. A locking member selectively retains the blade of the male connector in the socket of the female connector. The male connector, the female connector, and the locking member cooperate to form a resilient and selectively releasable modular limb joint.