Electro-Hydraulic Aircraft Actuator with Piezo Pump Integration

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Aircraft assembly actuators face challenges in reducing mass, size, and complexity while maintaining effective operation, especially in space-constrained environments, and require simplified maintenance and reduced hydraulic pathway complexity.

Innovation Solution

The use of a piezo-electric pump to drive the actuator, combined with a self-contained hydraulic fluid supply circuit featuring an accumulator and a single dedicated pump, allows for a reduced mass, size, and complexity aircraft assembly with a single electro-hydraulic actuator, minimizing interconnecting pathways and leveraging a passive chamber and choke assembly for efficient fluid management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a centralized aircraft hydraulic system is used to drive actuators, then reliable actuation is achieved, but system complexity and mass increase

Engineering Contradiction:
Improveactuator operation reliabilityVSAvoidhydraulic system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the centralized hydraulic system into distributed mini-hydraulic systems, with each actuator having its own dedicated pump and accumulator. This segmentation eliminates complex interconnecting pathways while maintaining reliable actuation at each location independently.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts the hydraulic power supply function from the centralized system and integrates it directly at the actuator location. Each actuator unit contains its own pump and accumulator, removing the need for complex centralized distribution infrastructure.

Inventive Principle:
Principle #2Taking out (Extraction)

2Weight of moving object

If actuator mass and size are reduced, then space constraints are better managed, but power density requirements increase

Engineering Contradiction:
Improveactuator massVSAvoidpower density
Core Design Contradiction:
Weight of moving objectVSPower

Solution Approach 1:

The patent employs a piezo-electric pump that operates dynamically with high-frequency oscillations to generate hydraulic pressure. This dynamic operation allows the small pump to deliver high power density despite its reduced mass and size, meeting the actuation requirements within compact dimensions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameters of the hydraulic system by using high-frequency piezo-electric actuation instead of traditional low-frequency mechanical pumping. This parameter change enables compact pump design while maintaining sufficient power output for actuator operation.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a single dedicated pump and accumulator are used per actuator, then interconnecting pathways are minimized, but component count increases

Engineering Contradiction:
Improvehydraulic pathway complexityVSAvoidnumber of hydraulic components
Core Design Contradiction:
Device complexityVSQuantity of substance

Solution Approach 1:

The patent merges the pump, accumulator, and actuator into an integrated mini-hydraulic system unit. While the component count increases locally, the merging eliminates the need for extensive interconnecting pathways and centralized distribution infrastructure, reducing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent designs universal mini-hydraulic units that can be applied to multiple actuators throughout the aircraft. Each unit performs multiple functions (pumping, storing, and actuating) in a compact package, making the system scalable without proportionally increasing complexity.

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

4Use of energy by moving object

If low power input is used (≤500 Watts), then energy consumption is reduced, but actuator force and speed may be limited

Engineering Contradiction:
Improvepower consumptionVSAvoidactuator output force
Core Design Contradiction:
Use of energy by moving objectVSForce

Solution Approach 1:

The patent uses hydraulic fluid pressure generated by the piezo-electric pump to amplify the output force of the actuator. The hydraulic system converts the low-power electrical input into high-pressure fluid that drives the actuator piston, achieving high force output from low power input through hydraulic pressure multiplication.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent changes the energy conversion parameters by using high-voltage, low-current electrical input to drive the piezo-electric pump, which then converts this to high-pressure hydraulic output. This parameter transformation enables low overall power consumption while maintaining high actuator force through pressure amplification.

Inventive Principle:
Principle #35Parameter changes

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

This configuration results in an aircraft assembly with reduced mass, size, and complexity, requiring less than 500 Watts of power, offering simplified maintenance and efficient operation, particularly suited for aircraft landing gear systems, with improved power density and reduced leakage risks.

Implementation Method 1

The actuator is driven by a piezo-electric pump

Methodology Applied
Scientific EffectPiezo-electric effect: Piezoelectric Effect

Implementation Method 2

The hydraulic fluid supply circuit comprises an accumulator for storing hydraulic fluid

Methodology Applied
Scientific EffectHydraulic pressure storage: Hydraulic Accumulator

Implementation Method 3

a piston and rod assembly slidably housed within the actuator casing so that the actuator can change between different extension states in response to fluid pressure

Methodology Applied
Scientific EffectHydraulic pressure force: Hydraulic Press

Data Source

PatentEP3505442B1Aircraft assembly
Publication Date: 2021.12.01 MESSIER DOWTY
  • EP3505442B1 patent drawingFigure 1
  • EP3505442B1 patent drawingFigure 2a
  • EP3505442B1 patent drawingFigure 2b

AI summary

An aircraft assembly (14) comprising: a first part (18a); a second part (20b), the second part being movably mounted with respect to the first part; an electro-hydraulic actuator (42) coupled between the second part and a first anchor point (18a), the actuator comprising a cylinder defining a bore and a piston and rod assembly slidably mounted within the bore and an active chamber within which an increase in fluid pressure causes the actuator to change during a first phase between first and second extension states to move the second part relative to the first part. The electro-hydraulic actuator further comprises a hydraulic fluid supply circuit comprising a piezo-electric pump operable to supply pressurised fluid to the active chamber to change the actuator between first and second extension states.