Aircraft Force Sensor Stops for Symmetrical Load Limiting

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Solution Overview

Problem

Piloting devices face challenges in accurately measuring forces during certification due to potential damage from excessive forces, as existing force sensors are not optimized for maximum certification forces, leading to uneven load distribution and erroneous readings.

Innovation Solution

Incorporating a mechanism with pairs of bearing surfaces and stops made of compliant materials to limit the angular amplitude of rotation and ensure symmetrical load distribution on the force sensor, reducing the risk of damage and improving measurement accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the force sensor is optimized for operational force values, then measurement precision for normal piloting is improved, but the sensor becomes vulnerable to damage from maximum certification forces

Engineering Contradiction:
Improveforce measurement precisionVSAvoidsensor durability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

A mechanical linkage system with bearing surfaces and stops acts as an intermediary between the piloting member and the force sensor. This intermediary mechanism transmits forces through controlled bearing surfaces while the stops limit the maximum force transmission, protecting the sensor from certification-level forces while maintaining measurement accuracy for operational forces

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the force transmission parameters by introducing bearing surfaces that alter the force path and stops that cap the maximum force magnitude. This parameter modification allows the sensor to operate in its optimal measurement range while being protected from excessive forces during certification testing

Inventive Principle:
Principle #35Parameter changes

2Reliability

If mechanical stops are used to limit rotation amplitude, then protection from excessive forces is achieved, but uneven load distribution causes erroneous measurements

Engineering Contradiction:
Improvesensor protectionVSAvoidforce measurement accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The bearing surfaces are strategically positioned at specific locations on the mechanical linkage to ensure symmetrical load distribution. By optimizing the local geometry and position of these bearing surfaces, the system achieves both protection through stops and accurate force transmission without erroneous measurements

Inventive Principle:
Principle #3Local quality

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 solution allows for precise force measurement and protection of the force sensor during certification, preventing damage and ensuring accurate flight control and feedback functionality.

Implementation Method 1

The at least one pair of stops comprises a compliant material

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

at least one force sensor measuring at least one component of the forces in the piloting device, by deformation of at least one deformable sensing element of the force sensor

Methodology Applied
Scientific EffectStrain gauge deformation: Piezoresistive Effect

Data Source

PatentEP4257483A1Stops for force sensor
Publication Date: 2023.10.11 RATIER FIGEAC SAS
  • EP4257483A1 patent drawingFigure 1
  • EP4257483A1 patent drawingFigure 2
  • EP4257483A1 patent drawingFigure 3A~3B

AI summary

A piloting device for piloting an aircraft, comprising a piloting member (11) suitable for being actuated by a pilot; a mechanism (13) for mounting and guiding in rotation the piloting member (11) about at least one rotation axis (15, 16) with respect to a frame (12); at least one force sensor (19) connected between the piloting member (11) and the mechanism (13) comprising at least one sensing element (30, 31) configured to produce a signal upon deformation indicative of a force applied to the piloting member (11); wherein the force sensor comprises at least one pair of bearing surfaces (32, 33); at least one pair of stops (25, 26) configured to limit the angular amplitude of rotation of the piloting member with respect to the frame on abutment of the at least one pair of bearing surfaces with at least one pair of stops; wherein at least one of the stops (25, 26) and/or at least one of the bearing surfaces (32, 33) comprises a compliant material.