Space Appendage Tie Rod Shockless Release Mechanism

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Solution Overview

Problem

Existing space appendage deployment systems face issues with geometric defects leading to dynamic defects and shocks during tie rod release, which can result in non-deployment of appendages and potential mission loss, due to the inability to effectively manage tie rod tension and relaxation.

Innovation Solution

A device comprising a tie rod with a separate component that can modify its tension independently of the retention mechanism, using a component with controlled thermal expansion or shape memory material to reduce shocks during release, allowing for standardized implementation and positioning to manage tie rod tension without affecting mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the tie rod is released suddenly to deploy the appendages, then the deployment speed is improved, but shocks are generated that can damage the appendages or satellite

Engineering Contradiction:
Improvedeployment speedVSAvoidshocks during release
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by heating the tie rod before release to induce thermal expansion. This pre-expansion reduces the tension in the tie rod prior to release, thereby minimizing the shock generated when the appendages are deployed. The heating is performed in advance of the actual release moment, allowing the system to prepare for deployment in a controlled manner.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent utilizes parameter changes by altering the temperature of the tie rod to control its length and tension. By changing the thermal state of the tie rod, the system can adjust the tension parameter before release, ensuring that the deployment occurs with minimal shock. This involves transitioning the tie rod from a high-tension state to a pre-expanded, lower-tension state before release.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If the tie rod is heated to expand it before release, then the shock during release is reduced, but the choice of material is limited and heating over the entire length is complicated

Engineering Contradiction:
Improveshock during releaseVSAvoidmaterial selection and heating implementation
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent applies segmentation by dividing the tie rod into distinct functional zones: a heated expansion zone where thermal expansion occurs to reduce tension, and non-heated zones that maintain mechanical strength. This segmentation allows selective heating of only the portion of the tie rod that needs to expand, rather than heating the entire length, thereby simplifying the heating implementation while still achieving shock reduction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements local quality by applying thermal expansion properties only to specific localized regions of the tie rod rather than the entire structure. This allows the tie rod to have different properties in different sections: one section with controlled thermal expansion for shock mitigation, and other sections maintaining conventional material properties for structural integrity. This resolves the material selection constraint by allowing different materials or treatments in different locations.

Inventive Principle:
Principle #3Local quality

3Device complexity

If geometric defects are not compensated for in the tie rod, then the device complexity is reduced, but dynamic defects result in radial forces or moments that can cause malfunction

Engineering Contradiction:
Improvetie rod design simplicityVSAvoiddeployment reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies the taking out principle by extracting and isolating the geometric defects from the main tie rod structure. Rather than attempting to compensate for defects throughout the entire tie rod, the invention identifies and addresses the specific defective regions separately. This allows the majority of the tie rod to maintain its simple design while targeted sections handle the geometric imperfections, thus balancing complexity and reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

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 solution enables shockless release of space appendages by decoupling mechanical and thermal resistance, allowing for precise tension control and reducing the risk of damage during deployment, thereby ensuring reliable appendage deployment and mission success.

Implementation Method 1

A device for holding and releasing an appendage, in which the device comprises a tie rod extending along an axis between two ends, a mechanism secured to the base and ensuring the temporary retention of a first of the ends of the tie rod... a component arranged between the mechanism and the end piece, the component being independent of the mechanism, and a command for the component making it possible to modify a characteristic dimension of the component along the axis

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

A device comprising a tie rod with a separate component that can modify its tension independently of the retention mechanism, using a component with controlled thermal expansion or shape memory material to reduce shocks during release

Methodology Applied
Scientific EffectShape memory effect: Shape Memory Alloy

Data Source

PatentEP3181461B1Device for holding and releasing appendages
Publication Date: 2020.10.07 THALES SA
  • EP3181461B1 patent drawingFigure 1a
  • EP3181461B1 patent drawingFigure 1b
  • EP3181461B1 patent drawingFigure 1c

AI summary

The present invention relates to an active tie rod allowing the shock-free holding and release of appendages.According to the invention, the device (10) comprises: • a fixed base (11), • a tie rod (12) extending along an axis (21) between two ends (14, 15), • a mechanism (13) integral with the base and ensuring the temporary retention of one end (14) of the tie rod (12), an operation of the mechanism allowing the tie rod (12) to be released from the base (11), • an end piece (16) integral with a second end (15) of the tie rod (12), • at least one appendage (AP) temporarily held between the base (11) and the end piece (16), • a component (20) disposed between the mechanism (13) and the end piece (16), • and a control (25) of the component (20) allowing a characteristic dimension of the component (20) to be modified along the axis (21) between two values, for a first of the two values, the component (20) ensuring a tension of the tie (12) and for a second of the two values, the tension of tie (12) being reduced.