Fiber Optic Actuator Trip Sensing for In-Flight Over-Torque Detection

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Solution Overview

Problem

Existing systems fail to provide real-time detection of over-torque conditions in actuators controlling slats and flaps on an airplane wing during flight, necessitating a solution that can alert pilots while airborne.

Innovation Solution

An optical system using a mechanical trip indicator coupled with an optical device and interferometer to detect phase changes in reflected light, determining the actuator's state and controlling slat or flap operations based on this detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a mechanical actuator is used to control slat and flap position, then the actuator can be inspected only when the airplane is on the ground, but the effects of over-torque conditions can be critical to flight safety

Engineering Contradiction:
Improveflight safetyVSAvoidinspection accessibility
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent replaces the purely mechanical inspection system with an optical measurement system. An optical sensor measures the position of a reflector attached to the actuator shaft, allowing real-time monitoring of actuator state during flight. This substitutes mechanical inspection with optical detection, enabling continuous monitoring without requiring ground-based physical inspection.

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

Solution Approach 2:

The patent implements a feedback system where the optical sensor continuously monitors the actuator position and sends signals back to the control system. When over-torque conditions cause the actuator to move beyond safe limits, the system detects this deviation and can trigger alerts or automatic corrective actions, providing real-time feedback on actuator health during flight operations.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If an optical sensor is used to measure actuator position in real-time, then over-torque conditions can be detected during flight, but the system complexity increases

Engineering Contradiction:
Improvereal-time detection capabilityVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a reflector as an intermediary element attached to the actuator shaft. The optical sensor measures the position of this reflector rather than directly measuring the actuator state. This intermediary approach simplifies the optical measurement system while enabling precise real-time detection of actuator position and over-torque conditions during flight.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Loss of information

If the actuator is inspected only when on the ground, then maintenance procedures remain simple, but critical over-torque effects cannot be detected during flight operations

Engineering Contradiction:
Improveover-torque condition detectionVSAvoidmaintenance procedure simplicity
Core Design Contradiction:
Loss of informationVSEase of manufacture

Solution Approach 1:

The patent enables continuous monitoring of actuator position throughout the entire flight operation, from takeoff to landing. The optical sensor continuously measures the reflector position, providing uninterrupted detection of over-torque conditions. This continuous action eliminates the information loss that occurs with ground-based inspection only, while the system integrates seamlessly into existing maintenance procedures.

Inventive Principle:
Principle #20Continuity of useful action

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 real-time detection of over-torque conditions in actuators, allowing pilots to take corrective actions during flight, enhancing safety by providing immediate feedback on actuator states.

Implementation Method 1

an optical device and interferometer to detect phase changes in reflected light

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 2

detect phase changes in reflected light

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP4400822B1Fiber optic actuator overload trip sensor
Publication Date: 2025.11.19 HAMILTON SUNDSTRAND CORP
  • EP4400822B1 patent drawingFigure 1
  • EP4400822B1 patent drawingFigure 2
  • EP4400822B1 patent drawingFigure 3~4

AI summary

An apparatus and a method of determining a state of an actuator (300) in an airplane (100). The apparatus includes a mirror (514) coupled to the actuator, wherein a location of the mirror is dependent on the state of the actuator, a shaft (314) for moving the mirror upon a change in the state of the actuator, and a processor. Incident light (520) is reflected off of the mirror to create a reflected light (522). The processor receives the reflected light from the mirror, detects a change in a parameter of the reflected light generated by moving of the mirror, and determines the state of the actuator based on the change in the parameter.