Capacitive Ground Detection for Aircraft Landing Gear

Solution Overview

Problem

Existing ground detection systems for aircraft rely on detecting compression of landing gear suspension, which can lead to delayed detection of ground contact as aircraft designs become lighter, potentially causing delayed braking and compromising shock-absorbing performance.

Innovation Solution

A ground detection system using capacitive sensing, where an electrode on the aircraft landing gear forms a variable capacitor with the ground, allowing for the measurement of capacitance and determination of the aircraft's distance from the ground, thereby detecting ground contact and proximity without relying on suspension compression.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If softer suspension is provided to enable quicker compression, then ground contact detection timing is improved, but shock-absorbing performance is compromised

Engineering Contradiction:

Improveground contact detection timeVSAvoidshock-absorbing performance

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The patent replaces the mechanical compression-based detection system with a capacitive sensing system. The electrode on the landing gear detects ground proximity through capacitive changes in the electric field, eliminating the need for suspension compression to trigger detection. This substitution allows the suspension to maintain its shock-absorbing design while enabling early ground contact detection before mechanical compression occurs.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediate capacitive sensing mechanism between the landing gear and ground detection system. The electrode creates a variable capacitor with the ground as the other electrode, allowing detection of ground proximity through electrical field interaction rather than direct mechanical contact or suspension compression. This intermediary enables detection without compromising suspension performance.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Weight of moving object

If lighter aircraft designs are used, then fuel efficiency and performance are improved, but ground contact detection is delayed due to reduced suspension compression

Engineering Contradiction:

Improveaircraft weightVSAvoidground contact detection time

Core Design Contradiction:

Weight of moving objectVSLoss of time

Solution Approach 1:

The patent replaces the mechanical compression-based detection system with a capacitive sensing system. The electrode on the landing gear detects ground proximity through capacitive changes in the electric field, eliminating the need for suspension compression to trigger detection. This substitution allows the suspension to maintain its shock-absorbing design while enabling early ground contact detection before mechanical compression occurs.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the detection parameter from mechanical compression distance to capacitive electric field strength. By monitoring changes in capacitance rather than mechanical displacement, the system can detect ground proximity at earlier stages of landing, before the lighter aircraft's reduced suspension compresses sufficiently to trigger traditional detection systems.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If traditional compression-based detection is used, then suspension design is constrained, but ground contact detection accuracy is maintained

Engineering Contradiction:

Improveground contact detection accuracyVSAvoidsuspension design flexibility

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent replaces the mechanical compression-based detection system with a capacitive sensing system. The electrode on the landing gear detects ground proximity through capacitive changes in the electric field, eliminating the need for suspension compression to trigger detection. This substitution allows the suspension to maintain its shock-absorbing design while enabling early ground contact detection before mechanical compression occurs.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediate capacitive sensing mechanism between the landing gear and ground detection system. The electrode creates a variable capacitor with the ground as the other electrode, allowing detection of ground proximity through electrical field interaction rather than direct mechanical contact or suspension compression. This intermediary enables detection without compromising suspension performance.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 system enables accurate and timely detection of ground contact and distance, allowing for prompt aircraft braking and optimizing suspension design without compromising shock absorption, thereby enhancing safety and operational efficiency.

Implementation Method 1

the electrode and the ground together form a variable capacitor having a capacitance that depends on a distance of the electrode from the ground

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS20250076040A1sensor

Publication Date: 2025.03.06 AIRBUS OPERATIONS LTD

AI summary

A ground detection system for an aircraft based on capacitive sensing. The system comprises an electrode mounted to an aircraft landing gear. As the aircraft landing gear approaches the ground, the electrode and the ground together form a variable capacitor having a capacitance that depends on a distance of the electrode from the ground. Signal processing electronics are used to measure the capacitance and, on the basis of the measured capacitance, determine a distance of the aircraft from the ground.