Aircraft Actuator Fluid Level Sensing via Resistive RFID Circuitry

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Solution Overview

Problem

Current aircraft trailing edge flaps lack effective methods for detecting fluid levels within actuators, which are crucial for maintaining optimal performance and functionality.

Innovation Solution

An actuator level detection system utilizing resistivity-based sensor circuitry and radiofrequency identification circuitry to monitor fluid levels within actuators, incorporating contact points and contactors to measure resistance changes, and a controller to quantify fluid loss or contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional fluid level detection methods are not implemented in aircraft actuators, then the actuator can operate without additional components, but the ability to detect fluid loss or contamination is lost

Engineering Contradiction:
Improveactuator operation reliabilityVSAvoiddetection system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the fluid level detection function with the existing actuator structure by integrating sensor circuitry that utilizes the actuator's own housing and fluid passages. The sensor circuitry is incorporated into the actuator assembly, merging the detection system with the actuator itself rather than adding completely separate detection components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sensor circuitry serves multiple functions: it detects fluid level, monitors fluid contamination, and provides information about actuator operating conditions. The same basic sensor structure can detect various fluid parameters, making the system multi-functional and reducing the need for separate specialized sensors for each parameter.

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

2Measurement precision

If sensor circuitry is added to detect fluid levels, then fluid loss and contamination can be detected, but the actuator structure becomes more complex

Engineering Contradiction:
Improvefluid level detection precisionVSAvoidactuator structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The detection system is segmented into discrete functional elements: sensor circuitry with conductive paths, contactors, and evaluation logic. This segmentation allows the complex detection function to be broken down into manageable components that can be integrated into the actuator in a structured manner, reducing overall system complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses the actuator's own fluid as an intermediary medium for detection. The fluid itself becomes part of the sensing mechanism, where its presence, level, and electrical properties (conductivity/resistivity) are used to detect its own condition. This eliminates the need for separate sensing media or complex external sensing systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If contact points and contactors are integrated into the actuator housing, then fluid level detection is enabled, but manufacturing complexity increases

Engineering Contradiction:
Improvefluid level monitoring capabilityVSAvoidactuator manufacturing complexity
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The contact points and contactors are merged with the actuator housing structure, eliminating the need for separate mounting fixtures or additional structural components. The housing itself serves as the mounting structure for the sensing elements, reducing manufacturing steps and assembly complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The actuator housing serves dual functions: it contains and protects the actuator mechanisms while simultaneously serving as the structural framework for the fluid level detection system. This multi-functionality reduces the total number of components and simplifies manufacturing by eliminating redundant structures.

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

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

Enables accurate detection of fluid loss or contamination in actuators, ensuring reliable operation of aircraft components by providing real-time feedback on fluid levels and integrity.

Implementation Method 1

sensor circuitry that includes a conductive path defining a conductive path resistance between the first contact point and the second contact point, the sensor circuitry having a total resistance that includes the first contact resistance and the conductive path resistance

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Implementation Method 2

radiofrequency identification circuitry has an antenna and includes sensor circuitry that includes a conductive path defining a conductive path resistance

Methodology Applied
Scientific EffectRadiofrequency identification: Electromagnetic Induction

Data Source

PatentEP4276345B1Aircraft actuator fluid level detection
Publication Date: 2025.11.26 HAMILTON SUNDSTRAND CORP
  • EP4276345B1 patent drawingFigure 1
  • EP4276345B1 patent drawingFigure 2A~2B
  • EP4276345B1 patent drawingFigure 3~4B

AI summary

Disclosed is an actuator level detection system (150) of an aircraft. The system includes an actuator (100) containing fluid (102) that defines a resistivity and including a first contact point (104) and a second contact point (106). The system includes a first contactor (112) disposed about the actuator (100) cooperating with the first contact point (104) to define a first contact resistance (124) that includes the resistivity. The system includes radiofrequency identification circuitry (200) having an antenna (204) and including sensor circuitry including a conductive path defining a conductive path resistance between the first contact point (104) and the second contact point (106), the sensor circuitry having a total resistance that includes the first contact resistance and the conductive path resistance.