Pneumatic Artificial Muscle Actuator with Integral Braking

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Solution Overview

Problem

Conventional linear actuators face issues with shock loads due to uncontrolled movement, leading to potential damage when braking systems are not used, and existing braking solutions like crush features or viscous damping add complexity and weight.

Innovation Solution

The integration of a pneumatic artificial muscle (PAM) actuator with end caps, an elastic bladder, and a covering that provides braking through venting mechanisms, allowing fluid to escape and collapse the bladder and covering to absorb shock and control movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional braking systems (crush features or viscous damping) are used to stop linear actuator movement, then shock loads are prevented, but device complexity and weight increase

Engineering Contradiction:
Improveshock load preventionVSAvoidbraking system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The braking function is merged with the actuator structure itself. The piston rod and cylinder bore form an integrated braking mechanism where the piston rod engages with the cylinder bore to create friction during retraction, eliminating the need for separate braking components while preventing shock loads.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The actuator uses its own structural components (piston rod and cylinder bore) to provide braking action. The friction between these components during retraction automatically dissipates kinetic energy and prevents shock loads without requiring external braking systems.

Inventive Principle:
Principle #25Self-service

2Reliability

If conventional braking systems (crush features or viscous damping) are used to stop linear actuator movement, then shock loads are prevented, but weight increases

Engineering Contradiction:
Improveshock load preventionVSAvoidbraking system weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The braking function is merged with the actuator structure itself. The piston rod and cylinder bore form an integrated braking mechanism where the piston rod engages with the cylinder bore to create friction during retraction, eliminating the need for separate braking components while preventing shock loads.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The actuator uses its own structural components (piston rod and cylinder bore) to provide braking action. The friction between these components during retraction automatically dissipates kinetic energy and prevents shock loads without requiring external braking systems.

Inventive Principle:
Principle #25Self-service

3Device complexity

If force balancing is attempted to avoid braking requirements, then system complexity may be reduced, but it is not always possible or desirable in some applications

Engineering Contradiction:
Improveforce balancing complexityVSAvoidapplication flexibility
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The actuator uses its own structural components (piston rod and cylinder bore) to provide braking action. The friction between these components during retraction automatically dissipates kinetic energy and prevents shock loads without requiring external braking systems.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The integrated braking mechanism works across multiple application scenarios without requiring design modifications. The same piston rod-cylinder bore interaction provides reliable braking whether the actuator is used for lifting, pushing, or other linear motion applications, maintaining versatility while simplifying design.

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

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

This approach enables high energy density linear actuation with integral braking, reducing the need for bulky braking systems, minimizing weight, cost, and providing inherent shock isolation, while allowing for misalignment tolerance in the actuator components.

Implementation Method 1

inflating an elastic bladder of the PAM actuator to move an object connected to the PAM actuator

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The integration of a pneumatic artificial muscle (PAM) actuator with end caps, an elastic bladder, and a covering that provides braking through venting mechanisms

Methodology Applied
Scientific EffectPneumatics: Pressurisation

Implementation Method 3

venting the elastic bladder while the object connected to the PAM actuator is moving

Methodology Applied
Scientific EffectVenting: Depressurisation

Implementation Method 4

braking the PAM actuator using at least the covering... providing inherent shock isolation

Methodology Applied
Scientific EffectShock absorption: Damping

Implementation Method 5

braking the PAM actuator using at least the covering... at least the covering configured to provide braking for the PAM actuator

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3311036B1Apparatus and method for high energy density linear actuation with integral braking
Publication Date: 2020.07.08 RAYTHEON CO
  • EP3311036B1 patent drawingFigure 1A~1B
  • EP3311036B1 patent drawingFigure 2A~2C
  • EP3311036B1 patent drawingFigure 2D~2E

AI summary

A pneumatic artificial muscle (PAM) actuator (100) includes first and second end caps (102-104), an elastic bladder (106) connected to the end caps, and a covering (108) around the elastic bladder and connected to the end caps. At least one of the first and second end caps is configured to move and narrow a distance between the end caps in response to inflation of the elastic bladder by a fluid. At least one of the end caps includes a vent (114) configured to allow the fluid to exit the elastic bladder and collapse the covering after activation of the PAM actuator. At least the covering is configured to provide braking for the PAM actuator. The covering may be configured to collapse at least partially between the first and second end caps to provide at least some of the braking for the PAM actuator.