Rotorcraft Blade Position Sensing With Chip-Scale LIDAR In Flight

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Solution Overview

Problem

Rotorcraft experience rougher flight conditions due to variations in blade position, which cannot be corrected during flight and often require maintenance depot visits for repositioning.

Innovation Solution

A system utilizing chip-scale LIDAR sensors to dynamically measure and modify blade positions in real-time during flight, including determining blade pitch, flap, and leading/lagging positions using coherent light illumination and photodetection, allowing for in-flight adjustments to maintain smooth flight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If blade position is not monitored and adjusted during flight, then the rotorcraft can maintain simple operation procedures, but the flight smoothness deteriorates due to blade position variations

Engineering Contradiction:
Improveoperation simplicityVSAvoidflight smoothness
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent replaces complex mechanical blade adjustment systems with an optical measurement system (laser tracker) that non-contactly measures blade position. This substitution allows for simplified operation while maintaining flight smoothness through real-time optical monitoring and feedback control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements a feedback control system where blade position is continuously measured during flight using laser tracking, and the measurements are used to adjust blade position in real-time. This closed-loop feedback maintains flight smoothness without complicating operation procedures.

Inventive Principle:
Principle #23Feedback

2Device complexity

If blade repositioning is performed only at maintenance depots, then the device complexity remains low, but the loss of time increases due to extended flight disruptions

Engineering Contradiction:
Improvesystem complexityVSAvoidflight disruption time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The patent transforms the static blade adjustment process (performed only at maintenance depots) into a dynamic, in-flight adjustment capability. The system allows blade repositioning during flight operations, dramatically reducing the time loss while adding controlled complexity through the measurement and control system.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces an intermediary measurement system (laser tracker and sensors) that enables precise blade position monitoring and adjustment during flight. This intermediary technology facilitates time-efficient blade repositioning without requiring complex disassembly or depot facilities.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If traditional blade measurement methods are used, then the manufacturing precision requirements are lower, but the measurement precision deteriorates due to inability to capture dynamic blade positions

Engineering Contradiction:
Improveblade fabrication toleranceVSAvoidblade position measurement accuracy
Core Design Contradiction:
Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The patent replaces static mechanical measurement methods with dynamic optical measurement (laser tracking). This substitution enables high-precision measurement of moving blades during flight, capturing dynamic position data that traditional methods cannot obtain, thereby improving measurement precision without relaxing manufacturing standards.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 immediate correction of blade positions during flight, improving smoothness and reducing the need for post-flight maintenance, thereby enhancing operational efficiency and passenger comfort.

Implementation Method 1

repeatedly illuminating the blade with coherent light during flight of the rotorcraft while the blade is rotating... detecting radiation scattered from the blade in response to illumination of the blade

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 2

A track sensor, which is a chip-scale light detection and ranging (LIDAR) sensor, carried by the fuselage of the rotorcraft

Methodology Applied
Scientific EffectLIDAR: LIDAR

Implementation Method 3

Each track sensor includes a laser source configured to repeatedly illuminate a blade of the rotorcraft with coherent light

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 4

the chip-scale LIDAR sensor includes a splitter configured to receive the radiation generated by the laser source and to split the radiation into a first portion that is directed to and serves to illuminate the blade of the rotorcraft, and a second portion that is directed toward the at least one photodetector

Methodology Applied
Scientific EffectBeam splitting: Reflection

Data Source

PatentEP3838749B1System and method for dynamically measuring blade position during flight of a rotorcraft
Publication Date: 2024.05.08 THE BOEING CO
  • EP3838749B1 patent drawingFigure 1~2
  • EP3838749B1 patent drawingFigure 3~4
  • EP3838749B1 patent drawingFigure 5~6

AI summary

A blade positioning system and method are provided to dynamically measure blade (14) position during flight of a rotorcraft (10). In the context of a method, a blade (14) of the rotorcraft (10) is repeatedly illuminated (50) by a light source during flight of the rotorcraft (10) while the blade (14) is rotating. The method also includes detecting radiation scattered from the blade in response to illumination (50) of the blade (14). The method further includes determining at least one of a blade pitch angle (ΔθP), a blade flap angle (ΔθF), a blade leading position or a blade lagging position based upon the radiation that is scattered from the blade (14) and detected. A rotorcraft (10) is also provided that includes a chip-scale light detection and ranging (LIDAR) sensor configured to illuminate (50) the plurality of blades (14) while the blades (14) are rotating in order to permit blade (14) position to be measured or to illuminate terrain beneath the rotorcraft (10) in order to provide an altitude measurement.