Exoskeleton Force Device with Gas and Compression Springs

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Solution Overview

Problem

Physical activities requiring repetitive lifting and bending, such as construction or agriculture, often exceed the physical capabilities of participants, necessitating assistance to enhance performance and reduce fatigue.

Innovation Solution

A wearable exoskeleton system with a leg differential system, force devices, and a release mechanism that assists users in bending and lifting by providing equal force loading and energy storage, allowing for comfortable and flexible operation without pre-loading, and enabling users to disengage assistance when needed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single compression spring is used for energy storage, then the device structure is simple, but the range of motion is limited

Engineering Contradiction:

Improverange of motionVSAvoiddevice structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines a gas spring and a compression spring into a single force device assembly. The gas spring provides initial force and supports the weight of the exoskeleton components, while the compression spring provides additional force during the lifting phase. This merging of two spring mechanisms allows the exoskeleton to achieve a larger range of motion without proportionally increasing structural complexity.

Inventive Principle:

Principle #5Merging (Combining)

2Force

If pre-loading is applied to the force device, then the lifting assistance is enhanced, but the user must exert more energy against the pre-loading

Engineering Contradiction:

Improvelifting assistanceVSAvoiduser energy expenditure

Core Design Contradiction:

ForceVSUse of energy by moving object

Solution Approach 1:

The gas spring is configured to support the weight of the exoskeleton components (thigh plate, shin plate, cables), effectively counterbalancing the dead weight of the device itself. This anti-weight approach allows the compression spring to focus on providing lifting assistance without needing excessive pre-loading, as the gas spring already handles the static weight support. Users experience reduced energy expenditure because they don't need to overcome the weight of the exoskeleton components.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

3Reliability

If the force device is always engaged, then the lifting assistance is continuous, but the user cannot perform activities like sitting or bending freely

Engineering Contradiction:

Improvecontinuous assistanceVSAvoidfreedom of movement

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The exoskeleton employs a dynamic engagement mechanism that allows the force device to be selectively activated or deactivated based on the user's needs. During walking or running activities, the force device can be disengaged to allow natural leg movement without resistance. During lifting activities, the force device engages to provide assistance. This dynamic adaptability resolves the contradiction between continuous assistance and freedom of movement.

Inventive Principle:

Principle #15Dynamics

4Ease of operation

If unequal leg placement is allowed during walking, then the walking motion is more natural, but the force loading on each leg becomes unbalanced

Engineering Contradiction:

Improvewalking naturalnessVSAvoidforce loading balance

Core Design Contradiction:

Ease of operationVSForce

Solution Approach 1:

The patent employs asymmetric cable routing and differential pulley mechanisms that allow each leg to operate independently with unequal placement during walking. The cable system is designed so that when one leg is forward and the other is back, the cable lengths and angles differ, naturally accommodating the asymmetric gait pattern. This asymmetric design maintains force loading balance by allowing each side to operate at its optimal mechanical advantage point during the walking cycle.

Inventive Principle:

Principle #4Asymmetry

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

The exoskeleton system enhances user performance by providing assistive torque during lifting and bending, reducing fatigue and discomfort, while allowing for flexible use without constant engagement of energy storage devices.

Implementation Method 1

The force device includes components, such as a gas spring and a compression spring, to provide a smooth force profile while maintaining a larger range of motion than a single compression spring would provide

Methodology Applied

Scientific EffectSpring: Spring

Implementation Method 2

Methodology Applied

Scientific EffectGas spring: Spring

Data Source

PatentUS11793703B2Lift-assistance exoskeleton

Publication Date: 2023.10.24 VIRGINIA TECH INTELLECTUAL PROPERTIES INC

AI summary

An exoskeleton system and associated components are described herein. The exoskeleton system assists a user in lifting and/or bending to perform various operations. Components of the exoskeleton system can include a force device, a release mechanism, and a leg differential system. The force device includes a gas spring and a compression spring to store and release energy to assist a user of the exoskeleton system, the force device having a smooth force profile with no initial loading. The release mechanism disengages and re-engages the force device when actuated by a user. The leg differential system enables walking while wearing the exoskeleton system and equally loads different force devices of the exoskeleton system when a user's legs are displaced relative to one another.