Nested Dual-Path Actuator for Thin Wing Aircraft Reliability

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Solution Overview

Problem

Aircraft flight control actuators are prone to failure, leading to potential loss of control, especially in thinner wing designs where space is limited, and existing solutions do not ensure reliable operation in case of actuator failure.

Innovation Solution

A dual-path actuator system with a primary and secondary torque-generating mechanism, where each drive shaft is hollow and nested, allowing independent control of aircraft flight control surfaces, ensuring safe operation even if one path fails, and a compact design for thin wing aircraft.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single-path actuator is used, then the device complexity is reduced, but the reliability deteriorates due to risk of control surface floating upon failure

Engineering Contradiction:
Improveactuator reliabilityVSAvoidactuator structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The actuator is divided into two independent control paths (primary and secondary), each capable of independently actuating the control surface. This segmentation allows the system to maintain reliability through redundancy while keeping each individual path relatively simple in structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a backup control path that is prepared in advance to take over if the primary path fails. This beforehand cushioning ensures that upon failure, the control surface does not float but is immediately taken over by the secondary path, preventing catastrophic loss of control.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Adaptability or versatility

If the actuator size is reduced to fit thin wings, then the adaptability to modern aircraft design is improved, but the reliability deteriorates due to increased risk of failure

Engineering Contradiction:
Improveadaptability to thin wing designVSAvoidactuator reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent employs a nested configuration where the second drive shaft is positioned concentrically within the first drive shaft. This nesting allows both drive shafts and their associated components to share the same radial space, significantly reducing the overall actuator diameter to accommodate thin wing designs while maintaining dual-path redundancy for reliability.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

Instead of placing the second control path adjacent to or outside the first path (which would increase radial dimension), the patent utilizes the axial dimension by nesting the second drive shaft within the first. This dimensional reorganization allows compact packaging without compromising the independent functionality of either path.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If a dual-path actuator system is implemented, then the reliability is improved through redundancy, but the device complexity increases

Engineering Contradiction:
Improvecontrol surface positioning reliabilityVSAvoiddual-path system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The nested configuration of drive shafts and relief structures allows the dual-path system to share common spatial envelope and mounting interfaces, reducing the overall complexity increase that would normally accompany redundant systems. The concentric arrangement minimizes additional external components.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

Both the primary and secondary paths utilize similar component types (drive shafts, reliefs, braking mechanisms), allowing for standardized manufacturing and maintenance procedures. This universality reduces operational complexity despite the increased redundancy.

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

Data Source

PatentEP3145810B1Actuator for controlling a flight control surface
Publication Date: 2018.11.14 SAFRAN ELECTRONICS & DEFENSE (FR)
  • EP3145810B1 patent drawingFigure 1
  • EP3145810B1 patent drawingFigure 2
  • EP3145810B1 patent drawingFigure 3

AI summary

The invention relates to an actuator (4) for controlling a flight control surface (3) of an aircraft, comprising: - a primary route (5) comprising a first member (8) for generating a first torque, and a first drive shaft (10) having an end (18) able to be connected to the first member (8) and an end (19) able to be connected to the control surface (3), - a secondary route (6) comprising a second member (24) for generating a second torque and a second drive shaft (26) having an end (45) able to be connected to the second member (24) and an end (46) able to be connected to the control surface (3), in which actuator the second drive shaft (10) is hollow and extends around the first drive shaft (26).