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08 T

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athW

orks

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Steve Miller

Technical Marketing, Physical Modeling Tools

The MathWorks GmbH, Munich, Germany

Steve.Miller@mathworks.de

Using Physical Modeling Tools to Design Power Optimized Aircraft

Actuator Force

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Key Points

1. Testing different actuatordesigns in one environmentsaves time and encouragesinnovation

2. Optimizing systems with respectto design requirements leads to optimal design choices

3. Simulating at different levels of fidelity is required to see effectsof design implementation

Actuator ForceAileron Angle

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AgendaTrends in the aerospace industry 10 min

Industry trendsStrategies for improvementHow simulation can help

Example: Flight Actuation System 15 minModel explanationTradeoff studySystem optimizationAssess implementation effects

Conclusions

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Industry Trends

System needsAircraft must produce less pollutionAircraft must be more efficient

Example goalsClean Sky (for year 2020)

50% reduction of CO2 emissions80% reduction of nitrous oxide emissions

Power Optimized Aircraft (POA)25% cut in peak non-propulsive power5% reduction in fuel consumption

Strategies include aircraft-level optimization, technology

“With 5-6°C warming … existing models … estimate an average

5-10% loss in global GDP.”

“With 5-6°C warming … existing models … estimate an average

5-10% loss in global GDP.”

Head of the Government Economic ServiceUK, 2006

Research project, EU and industry

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Strategies for Improved Aircraft Design

Technology: Electrical actuationFewer losses than hydraulic actuationOnly needs to be turned on when in useTend to be more reliable, cleaner, and safer

Aircraft-level optimizationConsolidation of power electronicsLocalize hydraulic actuation

Simulation can help with each of these strategies

Boeing 787 Electrical Systems

BrakesIce protectionEngine start

Environmental controls Electrohydraulic pumps

Boeing 787 Electrical Systems

BrakesIce protectionEngine start

Environmental controls Electrohydraulic pumps

Airbus 380Electrical Systems

Primary flight control actuatorsThrust reverser actuation

Horizontal stabilizer backup

Airbus 380Electrical Systems

Primary flight control actuatorsThrust reverser actuation

Horizontal stabilizer backup

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How Simulation Can Help

1. Tradeoff studies to test electrical and hydraulic systemsDetermine actuator requirementsTest hydraulic and electrical actuator designs

2. System-level modelsMust be done at aircraft level to optimize architectureFew key parameters and quick simulation

3. Simulating at different levels of fidelityNeed to easily add fidelity to see impacts of implementationReuse work done at system level (Model-Based Design)

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Example: Aileron Actuation System

System

Simulation goals1. Determine requirements for actuation system2. Test performance with electrical or hydraulic actuation3. Optimize the actuation system4. Assess effects of system implementation

Control Actuation

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Determining Actuation Requirements

Problem: Determine the requirements for an aircraft aileron actuator

Solution: Use SimMechanics™ to model the aileron and Simscape™to model an ideal actuator

Model:

IdealActuator

θAileron

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Test Electrical and Hydraulic Designs

Problem: Test different actuator designs in the systemSolution: Use SimHydraulics®

and Simscape to model the actuators, and configurable subsystems to exchange them

Model:

Electro-mechanical

Hydraulic

Actuator

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Actuator System-Level Designs

Hydrostatic transmission

Variable-displacement pump Double-acting hydraulic cylinderReplenishing valvesPressure-relief valvesCharge pumpSpeed controller

Electromechanical system

DC MotorWorm gearCurrent sensorand current controllerHall effect sensorand speed controller

SpeedControl

CurrentControl

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Optimize System Performance

Problem: Optimize the speed controller to meet system requirementsSolution: Use Simulink® Response Optimization™ to tune the controller parameters

Model:

ω

Angle

Current

Kp Ki

0.3 0.3

CurrentControl

SpeedControl

i

ωSpeed

Control

Kp Ki

23.4 3.67

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Assess Implementation Effects

Problem: Assess the effects of design implementation on system performanceSolution: Use Simscape to add a the analog circuit implementation

Model: Current

CurrentControlSpeed

Control

ωi

1s

Simulink Circuit

ω i

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Conclusion1. Testing different actuator

designs in one environmentsaves time and encouragesinnovation

2. Optimizing systems with respectto design requirements leads to optimal design choices

3. Simulating at different levels of fidelity is required to see effectsof design implementation

Actuator ForceAileron Angle

14

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MathWorks Products Used

SimscapeMultidomain physical systems

SimMechanics3-D mechanical systems

SimHydraulicsHydraulic (fluid power) systems

Simulink Response Optimization

MATLAB, Simulink

Sim

Pow

erSy

stem

sTM

Simscape

Sim

Mec

hani

cs

Sim

Driv

elin

e

Sim

Hyd

raul

ics