Ice Thickness Sensor Array for Aircraft Angle of Attack Control

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Solution Overview

Problem

Current aircraft systems lack effective real-time monitoring and warning capabilities to prevent stalls caused by ice accumulation on airfoils, which can lead to unexpected loss of lift and control during flight.

Innovation Solution

A system comprising sensors to measure ice thickness and lift calculation variables, generating a threshold angle of attack value using a lookup table, and sending real-time adjustments to the flight data to maintain the aircraft within a safe angle of attack, thereby preventing stalls.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If real-time ice thickness measurement is implemented using multiple sensors, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveice thickness measurement precisionVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The airfoil surface is divided into multiple measurement positions, with sensors distributed at different locations (leading edge, mid-chord, trailing edge) to measure ice thickness locally. This segmentation enables comprehensive coverage of ice accumulation patterns while maintaining manageable sensor individual complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sensor system is designed to perform multiple functions: measuring ice thickness, determining ice accumulation patterns, and providing data for threshold angle of attack calculation. This multi-functionality reduces the need for separate measurement systems and integrates monitoring capabilities into a unified device

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

2Reliability

If real-time updates of threshold angle of attack are performed based on changing ice thickness, then reliability is improved, but use of energy increases

Engineering Contradiction:
Improvestall prevention reliabilityVSAvoidcomputing system energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system performs periodic updates of the threshold angle of attack at discrete time intervals (first time, second time) rather than continuous real-time calculation. This periodic operation reduces computational energy consumption while maintaining sufficient reliability for stall prevention by updating at critical moments when ice accumulation changes

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The threshold angle of attack is made dynamic, changing in real-time based on current ice thickness measurements and flight conditions. The system adapts the threshold value dynamically rather than using fixed predetermined values, improving reliability by matching actual aircraft performance under varying icing conditions

Inventive Principle:
Principle #15Dynamics

3Reliability

If the system provides comprehensive real-time monitoring and adjustment of angle of attack, then safety is improved, but device complexity increases

Engineering Contradiction:
Improveflight safetyVSAvoidmonitoring and control system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system implements a closed-loop feedback mechanism where ice thickness measurements are continuously monitored, the threshold angle of attack is recalculated based on current conditions, and alerts or control signals are generated when the actual angle of attack approaches the threshold. This feedback loop automates the monitoring and response process, improving safety while managing complexity through systematic control architecture

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The processing system acts as an intermediary between the sensor measurements and the flight control system. It receives raw ice thickness data, processes it through lookup tables and calculations to determine threshold values, and then communicates with the flight control system. This intermediary layer simplifies the overall system architecture by centralizing the complex processing logic in a dedicated component

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3954612B1A system and method for determining the real-time effect of ice accumulation on aircraft surfaces on angle of attack during flight
Publication Date: 2023.10.04 LOCKHEED MARTIN CORP
  • EP3954612B1 patent drawingFigure 1A~1B
  • EP3954612B1 patent drawingFigure 2
  • EP3954612B1 patent drawingFigure 3

AI summary

A system 100 includes a plurality of sensors 104 along a surface of an airfoil 108 operable to measure a first set of ice thickness values at a first time and a second set of ice thickness values at a second time. The system 100 further includes a processor 118 configured to determine a first plurality of lift calculation variables and a second plurality of lift calculation variables. The processor 118 also generates a threshold angle of attack value and updates the threshold angle of attack value at the second time, based on one or more differences between the first and second sets of ice thickness values and the first and second plurality of lift calculation variables. The processor 118 is further configured to send, to a display 126, based on the updated threshold angle of attack, one or more changes to flight data to adjust the actual angle of attack 128 of the airfoil 108.