Variable Geometry Rudder with Flexible Skins for Lower Actuation Energy

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Solution Overview

Problem

Aircraft control surfaces require significant energy expenditure to achieve desired lift coefficients due to their rigid nature, as described in existing technologies.

Innovation Solution

A variable geometry control system utilizing flexible skins and actuators to deform the control surfaces, reducing the necessary deflection angle and energy consumption by allowing curvature of the skins, with actuator shafts and auxiliary axes guiding the deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a rigid control surface is used, then the structural strength is improved, but the energy consumption increases significantly

Engineering Contradiction:
Improvestructural strengthVSAvoidenergy consumption
Core Design Contradiction:
StrengthVSUse of energy by moving object

Solution Approach 1:

The control surface transitions from a rigid structure to a dynamic flexible structure that can change its geometry. The flexible skin allows the control surface to adapt its shape continuously, reducing the energy required for actuation while maintaining structural integrity through strategic reinforcement zones.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control surface employs a flexible skin that can deform to achieve the desired deflection angles. This flexible membrane structure replaces the traditional rigid control surface, enabling energy-efficient actuation while the selective reinforcement zones provide necessary structural strength at critical locations.

Inventive Principle:
Principle #30Flexible shells and thin films

2Strength

If the flexible skin thickness is increased throughout to improve strength, then the structural strength is improved, but the weight increases

Engineering Contradiction:
Improvestructural strengthVSAvoidweight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The flexible skin features non-uniform thickness distribution with strategically placed reinforcement zones at the trailing edge and attachment points where structural strength is most needed. The central area maintains thinner construction to minimize weight, while critical regions receive localized thickening to ensure structural integrity during operation.

Inventive Principle:
Principle #3Local quality

3Reliability

If a rigid control surface with large deflection angle is used, then the lift coefficient is improved, but the energy consumption increases

Engineering Contradiction:
Improvelift coefficientVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The flexible control surface achieves the required lift coefficient through dynamic shape changes rather than large rigid deflections. The flexible skin allows for gradual curvature changes that produce the necessary aerodynamic forces with minimal actuator movement, significantly reducing energy consumption while maintaining effective lift generation.

Inventive Principle:
Principle #15Dynamics

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 system reduces the energy required for actuation by minimizing the necessary deflection angle, thus optimizing energy use in aircraft control surfaces.

Implementation Method 1

the displacement of the lower soft skin causing a curvature of the upper soft skin and a curvature of the lower soft skin

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4186784B1Variable geometry rudder system for an aircraft wing
Publication Date: 2025.08.27 AIRBUS OPERATIONS (SAS)
  • EP4186784B1 patent drawingFigure 1~3
  • EP4186784B1 patent drawingFigure 4~5
  • EP4186784B1 patent drawingFigure 6~7

AI summary

- Variable geometry control system for an aircraft wing. - The system (1) comprises at least one upper flexible skin (5) intended to be fixed in line with an upper plane (3) of the wing (2), a lower flexible skin (6) intended to be movable in line with a lower plane (4) of the wing (2) and fixed along a trailing edge (7) of the control surface (1), and an actuator (8) for generating a displacement (D) of the lower flexible skin (6) relative to the lower plane (4). The displacement (D) causes a curvature of the first upper flexible skin (5) and a curvature of the second lower flexible skin (6), both having a concavity (C1, C2) oriented in the same direction. The control system allows the amount of energy supplied by the actuator to be reduced.