Fly-By-Wire Architecture With Fewer Links for Flight Control Integrity

Solution Overview

Problem

Existing electric flight control systems are bulky and heavy due to redundant manual control systems, which complicates aircraft design and increases mass and volume, while also requiring high integrity and availability rates to ensure safety without the need for manual controls.

Innovation Solution

An electric flight control system with a three-stage architecture, utilizing encoding units and monitoring computers to verify the integrity of stick positions and control surface calculations, reducing the number of communication links from eight to four, and implementing cyclic redundancy checks to ensure data integrity and availability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If redundant processors and doubled communication links are implemented to guarantee safety, then reliability is improved, but device complexity and mass increase

Engineering Contradiction:

ImprovesafetyVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the traditional mechanical linkage-based backup manual control system with an electric flight control system. This substitution eliminates the need for bulky mechanical components while maintaining safety through redundant processors and communication links, thereby improving reliability without proportionally increasing device complexity and mass.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the parameter of communication links from traditional multi-link architectures to a optimized configuration with a limited number of unidirectional communication links. This parameter change reduces the number of links while maintaining integrity through careful architectural design, thus improving reliability without excessive complexity increase.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If redundant processors and communication links are implemented to guarantee safety, then reliability is improved, but mass increases

Engineering Contradiction:

ImprovesafetyVSAvoidmass

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent replaces the traditional mechanical linkage-based backup manual control system with an electric flight control system. This substitution eliminates the need for bulky mechanical components while maintaining safety through redundant processors and communication links, thereby improving reliability without proportionally increasing device complexity and mass.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If the number of communication links is reduced, then device complexity and mass are reduced, but reliability may deteriorate

Engineering Contradiction:

Improvedevice complexityVSAvoidintegrity rate

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent changes the parameter of communication links from traditional multi-link architectures to a optimized configuration with a limited number of unidirectional communication links. This parameter change reduces the number of links while maintaining integrity through careful architectural design, thus improving reliability without excessive complexity increase.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements monitoring processors that verify the integrity of calculations performed by control processors. This feedback mechanism ensures that even with reduced communication links, the system maintains high reliability through continuous verification and error detection, preventing integrity degradation despite link reduction.

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP3008533B1Fly-by-wire system for an aircraft

Publication Date: 2021.02.17 EUROCOPTER FRANCE SA

Figure 1~3
Figure 2
Figure 4

AI summary

The invention relates to a fly-by-wire system which comprises: three-stage piloting control (4), each stage including a control computer (16, 18, 20) suitable for determining the positions of the stick, and a monitoring computer (22, 24, 26) capable of verifying all the pre-determined positions of the stick; three-stage control-surface position calculation (6), each stage including a control computer (40, 42, 44) suitable for calculating the control-surface positions from encoded positions of the stick, and a monitoring computer (46, 48, 50) capable of verifying all the calculated control-surface positions; a single unidirectional communication link (88) connecting the control computer (16) of the first piloting control stage to the control computer (40) of the first control-surface position calculation stage; a single unidirectional communication link (132) connecting the control computer (18) of the second piloting control stage to the control computer (42) of the second control-surface position calculation stage; and a single unidirectional communication link (142) connecting the control computer (20) of the third piloting control stage to the control computer (44) of the third control-surface position calculation stage.