Aircraft Landing Gear Differential Braking Control During De-rotation

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Solution Overview

Problem

Existing aircraft braking systems do not provide differential braking capabilities during the de-rotation phase after landing, which can lead to excessive braking and potential damage to the aircraft.

Innovation Solution

A method and control system that adjusts the braking parameters of the left and right landing gear wheels by reducing the braking force while maintaining the differential braking difference, ensuring that the desired differential braking is applied without exceeding safety thresholds, thereby reducing the risk of damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If full desired braking parameters are applied during de-rotation phase, then differential braking effectiveness is improved, but risk of aircraft damage increases

Engineering Contradiction:
Improvedifferential braking effectivenessVSAvoidrisk of aircraft damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system changes the braking parameter values by applying a reduction factor to the desired braking parameters during the de-rotation phase. This reduces the absolute braking force applied to the wheels while preserving the differential braking capability, thus preventing damage while maintaining steering effectiveness.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system preemptively reduces the braking force before damage can occur by detecting the de-rotation phase and automatically applying reduced braking parameters. This prevents the harmful effect of excessive braking stress on the aircraft structure during the vulnerable de-rotation period.

Inventive Principle:
Principle #9Preliminary anti-action

2Object-affected harmful factors

If braking force is reduced during de-rotation phase, then risk of aircraft damage is limited, but differential braking capability may be compromised

Engineering Contradiction:
Improvebraking force on wheelsVSAvoiddifferential braking capability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The system applies a proportional reduction to both left and right braking parameters while maintaining their difference. This ensures that the differential braking capability (L'-R'=L-R) is preserved even though the absolute braking force is reduced, allowing effective steering while preventing damage.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If automatic braking function is applied without differential capability, then system simplicity is maintained, but turning control during de-rotation is insufficient

Engineering Contradiction:
Improvebraking system complexityVSAvoidturning control capability
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The braking control is segmented into independent left and right channel controls, allowing differential braking to be applied during de-rotation phase. This maintains the simplicity of automatic braking while adding the capability for differential control through separate parameter adjustment for each side.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2974957B1Differential braking of aircraft landing gear wheels
Publication Date: 2021.09.01 AIRBUS OPERATIONS LTD
  • EP2974957B1 patent drawingFigure 1a~1c
  • EP2974957B1 patent drawingFigure 2
  • EP2974957B1 patent drawingFigure 3

AI summary

A method of braking left and light landing gear wheels on respective left and right sides of an aircraft. A desired left braking parameter (L) is received for the left wheel and a desired right braking parameter (R) is received for the right wheel. The left wheel is braked with a reduced left braking parameter (L') which is less than the desired left braking parameter (L), and the right wheel is braked with a reduced light braking parameter (R') which is less than the desired right braking parameter (R). A difference between the braking parameters is maintained so that L'-R'=L-R.