AMR Sensor Flap Measurement for Rotor Hub

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Solution Overview

Problem

Rotor-hub flapping measurement systems in VTOL rotary aircraft face challenges with existing rotary-variable-differential transducer (RVDT) sensors due to size, weight, cost, complexity, and sensitivity to temperature and mechanical vibration.

Innovation Solution

The implementation of anisotropic magneto-resistive (AMR) sensor systems, coupled with a flap-linkage arm, to measure rotor-hub flapping by detecting movement relative to the main-rotor axis, utilizing multiple sensor arrangements for robustness and error identification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If RVDT sensors are used for rotor-hub flapping measurement, then measurement capability is achieved, but size, weight, cost, and device complexity increase

Engineering Contradiction:

Improveflapping measurement capabilityVSAvoidcomplexity of electronics

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical RVDT sensor system with an AMR sensor system that uses magnetic field detection instead of mechanical components. The AMR sensor detects changes in magnetic field orientation caused by flap-linkage arm movement, eliminating complex mechanical electronics while maintaining measurement capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the measurement parameter from direct mechanical displacement (RVDT) to magnetic field orientation changes (AMR). By attaching a magnet to the flap-linkage arm and using an AMR sensor to detect its orientation, the system measures flapping through magnetic parameter changes rather than mechanical parameter changes.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If RVDT sensors are used for rotor-hub flapping measurement, then measurement capability is achieved, but size and weight increase

Engineering Contradiction:

Improveflapping measurement capabilityVSAvoidsensor system weight

Core Design Contradiction:

Measurement precisionVSWeight of moving object

Solution Approach 1:

The patent replaces the heavy mechanical RVDT sensor assembly with a compact AMR sensor and magnet combination. The AMR sensor is a solid-state device with no moving parts, significantly reducing weight while maintaining measurement functionality through magnetic field detection.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts the essential measurement function from the bulky RVDT mechanism and implements it through a minimalistic AMR sensor-magnet system. Only the critical magnetic field detection components are retained, eliminating unnecessary mechanical weight.

Inventive Principle:

Principle #2Taking out (Extraction)

3Measurement precision

If RVDT sensors are used for rotor-hub flapping measurement, then measurement capability is achieved, but sensitivity to temperature and mechanical vibration increases

Engineering Contradiction:

Improveflapping measurement capabilityVSAvoidsensitivity to temperature and mechanical vibration

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanically-sensitive RVDT system with an AMR sensor system that is inherently more resistant to mechanical vibration. The solid-state AMR sensor has no moving parts that can be affected by vibration, and magnetic field detection is less sensitive to temperature variations than mechanical components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a magnet as an intermediary between the flap-linkage arm movement and the sensor detection. This magnetic field mediator transmits movement information to the AMR sensor without requiring direct mechanical contact, reducing sensitivity to mechanical disturbances and temperature effects.

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

The AMR sensor system provides improved sensitivity and reduced variation in measurement, offering a more reliable and less complex alternative to RVDT systems, with enhanced robustness through multiple sensor configurations and error detection capabilities.

Implementation Method 1

a magneto-resistive sensor system rotatably coupled to a second end of the flap-linkage arm and responsive to movement of the flap-linkage arm

Methodology Applied

Scientific EffectAnisotropic magneto-resistive effect: Magnetoresistance

Data Source

PatentUS12145721B2Anisotropic magneto-resistive sensor flap measuring systems

Publication Date: 2024.11.19 TEXTRON INNOVATIONS INC

AI summary

A rotor-hub flap-measurement system includes a rotor hub operable to flap relative to a main-rotor axis, a flap-linkage arm, a first end of the flap-linkage arm rotatably coupled to the rotor hub, the flap-linkage arm responsive to flapping of the rotor hub, and a magneto-resistive sensor system rotatably coupled to a second end of the flap-linkage arm and responsive to movement of the flap-linkage arm.