Electromechanical Decoupler for Aircraft Flight Control

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Solution Overview

Problem

Aircraft pilots face excessive inertia forces from actuators during flight, which can lead to loss of control and injury, as existing systems lack effective decoupling mechanisms to manage these forces without power assistance.

Innovation Solution

An electromechanical decoupler system that uses a decoupler plate with axial grooves and pinholes, coil springs, and electromagnets to disconnect and reconnect the manual control devices from the actuator, allowing for separation from excessive forces and reconnection when safe, ensuring pilot control and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the actuator is operatively connected to the manual control device, then the actuator can assist the pilot in controlling the aircraft, but excessive inertia forces from the actuator can be transmitted back to the pilot during flight maneuvers

Engineering Contradiction:
Improveease of controlVSAvoidexcessive inertia forces
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

A decoupler mechanism is introduced as an intermediary between the actuator and manual control device. This decoupler includes a decoupler plate with projections that can engage or disengage from housing projections, allowing the system to switch between coupled and decoupled states. When decoupled, the harmful inertia forces are isolated from the pilot while the actuator remains connected to the flight control surfaces.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system transitions from a static connected state to a dynamic state where the connection can be changed. The decoupler plate is designed to move axially along the shaft, enabling it to engage with or disengage from the housing projections based on operational conditions. This dynamic capability allows the system to adapt between providing assistance and isolating harmful forces.

Inventive Principle:
Principle #15Dynamics

2Object-affected harmful factors

If the actuator is disconnected from the manual control device, then the pilot is protected from excessive inertia forces, but the pilot loses the ability to backdrive the actuator for manual control

Engineering Contradiction:
Improveexcessive inertia forcesVSAvoidmanual control capability
Core Design Contradiction:
Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The decoupler mechanism provides dynamic adaptability by allowing the system to switch between two operational modes: coupled mode where the pilot can backdrive the actuator, and decoupled mode where the pilot is protected from excessive forces. The alignment pins and pinholes ensure proper rotational alignment is maintained in both modes, preserving manual control capability when needed while providing protection when necessary.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control system is segmented into distinct functional components: the actuator, the decoupler mechanism, and the manual control device. This segmentation allows independent operation of each component while maintaining the ability to connect or disconnect them as needed, providing both protection and manual control capability.

Inventive Principle:
Principle #1Segmentation

3Object-affected harmful factors

If a decoupling mechanism is added between the actuator and manual control device, then the pilot can be separated from excessive forces, but the device complexity increases

Engineering Contradiction:
Improveexcessive inertia forcesVSAvoiddecoupler mechanism complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The decoupler plate combines multiple functions into a single component: it provides axial movement for engagement/disengagement, includes projections for mechanical coupling, has pinholes for alignment, and works with the spring and electromagnets. This merging reduces the number of separate parts needed while achieving the required decoupling functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The spring-loaded decoupler mechanism automatically engages or disengages based on the position of the decoupler plate, without requiring external actuation. The alignment pins and pinholes automatically ensure proper rotational alignment when the decoupler engages, eliminating the need for separate alignment mechanisms.

Inventive Principle:
Principle #25Self-service

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 effectively separates pilots from excessive inertia forces during actuator failures or passive mode backdriving, enabling continued control of aircraft flight surfaces without actuator assistance, enhancing pilot safety and operational reliability.

Implementation Method 1

A coil spring is mounted on the shaft. The coil spring engages between an annular spring retainer at one end of the shaft and the decoupler plate. The spring exerts a biasing force on the decoupler plate that urges the decoupler plate in the second axial direction

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

The electromagnets are operable to create magnetic fields between the electromagnets and the decoupler plate when activated. The magnetic field created pulls the decoupler plate against the bias force of a coil spring

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 3

There are five electromagnets employed in the electromechanical decoupler. Each of the electromagnets is secured to the end plate of the housing in the interior volume of the housing

Methodology Applied
Scientific EffectElectromagnet: Electromagnet

Data Source

PatentEP3251951B1Electromechanical decoupler
Publication Date: 2019.01.09 THE BOEING CO
  • EP3251951B1 patent drawingFigure 1
  • EP3251951B1 patent drawingFigure 2
  • EP3251951B1 patent drawingFigure 3

AI summary

A compact electromechanical decoupler device (26) is operatively connected between a manual control device of an aircraft (14) and an electromechanical actuator (22) that controls the flight modes of the aircraft. The electromechanical decoupler device is operable to decouple the operative connection between the manual control device and the electromechanical actuator with the absence of power supplied to the electromechanical decoupler device. The electromechanical decoupler device can recouple the operative connection between the manual control device and the electromechanical actuator on resupply of power to the electromechanical decoupler device and on manually achieving proper rotational alignment or indexing between the mechanical control device and the electromechanical actuator.