distributed and redundant electro-mechanical nose wheel steering system · 2015. 11. 6. · dress...

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This document and the information contained are Messier-Bugatti property and shall not be copied or disclosed to any third party without Messier-Bugatti prior written authorization

DRESS

Distributed and Redundant Electro-mechanical nose wheel

Steering System

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DRESS CHARACTERISTICS AND OBJECTIVES�European Commission funded project (FP6 - 3rd call - submitted in July 2005)

• Schedule:

� Kick Off : June 2006

� End : December 2009

• Consortium: 13 partners from 8 countries

� 4 Industries (Airbus, Messier-Dowty, Messie r-Bugatti, Saab)

� 1 Research Institute (Institute of Aviation)

� 5 Universities (INSA, UHA, UCL, UCV, BUTE)

� 3 SMEs (TTTech, Equipaero, Stridsberg)

• Budget

� Global total budget: 4 040 786 €

� Total funding: 2 460 892 €

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DRESS CHARACTERISTICS AND OBJECTIVES

�Objectives:

• Study & Validate a redundant electromechanical actuato r

• Study & Validate the control system based on a distribut ed architecture

• Particular attention to be paid to shimmy phenomenon (n ew system stiffness anddamping of oscillations with an electromechanical syste m)

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DRESS GENERAL PRESENTATION

�Background on nose wheel steering actuation:

• Hydraulically actuated steering systems used on current commercial aircraft

•Current probability for nose wheel steering system loss is low (10-5 / FH). In case of failure, the pilot can safely regain manual control us ing differential braking

� Current system safe, but limited if minimum visibilit y required (no CATIIIC landing)

� No potential automatic guidance relying on steering system

• Trend: - Effort to improve ATM (Air Traffic Managemen t)

- Move towards MEA (More Electric Aircraft)

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DRESS TECHNICAL SPECIFICATIONS

�Functional analysis performed to identify the needs without focu sing on solutions

�Main technical specifications, basis of DRESS desig n• Maximum torque ≈≈≈≈ 7000Nm• Maximum angular speed ≈≈≈≈ 20°/sec• Towing mode capability (free to castor)• Robust behavior regarding shimmy• Total loss of steering event: objective 10-9/FH

Limit

0

20

40

60

80

100

120

0 20 40 60 80 100

Rate @ wheel (% spec. rate max)

Tor

que

@ tu

rnin

g tu

be (

% s

pec.

torq

ue

max

)

Spec. min. actuator's transient capability

Restricted torque area

BldcMotor Reducer

Power 110% Ratio 900

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DESCRIPTION OF DRESS SOLUTION

�Actuator architecture

• 2 identical path to apply torque at turning tube lev el

• Each path composed of

-1 electric motor with its associated control unit

- 1 prime reducer (cyclodrive)

- 1 clutch

- 1 end reducer (worm gear)

• Normal configuration

⇒ Each path provide half of the demanded torque (torque summing)

• Failure of one path

⇒ Remaining path provide the full torque (sizing for a l imited number of occurrences)

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DESCRIPTION OF DRESS SOLUTION

AF

DX

COCKPIT AVIONICS BAY NOSE LANDING GEAR BAY NOSE LANDIN G GEAR

EMCU

EMCU

ATA 32 LocalField Bus T TP

CHA+CHB

RVDTMO TOR

MO TOR RVDT

PW

MP

WM

A/C Avioni cs BusAFDX

Commo n to ATA 32System

Specifi c to ATA 32Braking Co ntrol

System BCS

Speci fic to ATA 32Steering Co ntrol

SystemSCS

Speci fic to ATA 32L G E xtensio n

Retraction SystemL GERS

CAPT Ti ll er

CAPT BrakePed als

F/O Ti ll er

F/O BrakePed als

RVDT

ANALOGUE

ANALOGUE

DISC

DISC

DISC

DISC

ANALOGUE

DISC

DISC

DISC

Sp eci fic to ATA 32Mo nito ring Contro l

SystemMS

BCS

SCS

LGERS

MS

CPM ATA 32

BCS

SCS

LGERSMS

CPM ATA 32

BCSSCS

LGERSMS

CPM ATA 32

BCS

SCSLGERS

MS

RDC ATA 32

SCSLGE RS

MS

RDC ATA 32

SCSLGE RS

MS

RDC ATA 32

SCSLGE RS

MS

RDC ATA 32

BCS

SCSL GERS

RDC ATA 32

BCSSCS

L GERSA

NALO

GU

E an

dD

ISC

RET

E

RDC ATA 32

BCSSCS

L GERS

Lan din gG ear Lever

DIS

CRE

TE

A/SKIDSw itch

PU LL & TU R N

O FF

ON

PARK BRK

A/SKID

O FF

O N

ParkBrake

2 CBGs

�System architecture (for potential future aircraft)

• based on field bus TTP

(time trigger protocole)

• 3 cockpit RDC (acquisition node)

• 3 CPM (computation node)

• 3 Landing gear RDC

(acquisition node)

• 2 EMCU (motor control unit)

• 3 angular sensors

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DRESS PROTOTYPE

�Motor Key Characteristics• Stritorque motor, embedding resolver position sensor, power off brake, temperature monitoring.• Spline interface towards the transmission for bearing lifetime.

�EMCU Key Characteristics• Motor torque control• 270 VDC, 28 VDC• Redundant, isolated RS-485 with Time-Triggered Protocol by TTTech. • PWM motor drive with field-oriented control.• The prototype EMCU overrated for the application.

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DRESS PROTOTYPE

�ACTUATOR• Cyclo reducer• Clutch• Worm gear• Sized to withstand –55°C to 85°C

�NODE• A TTP module board (provided by TTTECH) dedicated to manage TTP communications and to host the applicative software Clutch• An IO-Board (HW and SW) developed by MB) dedicated to acquire sensors data (cockpit, VDTs, discrete, analog…) and controls actuators (Clutch, Brakes, …).

worm

worm

LGL

gear

Aircraft

front

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ACTUATOR RIG

�Actuator mounting frame with actuator load device

The objective of this rig is to test the DRESS actuator under several conditions (load, temperature…)

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SYSTEM RIG (ATCSS CONFIGURATION)

The objective of this rig is to test the DRESS system (steering precision and dynamic, avionic behavior, TTP functionality…)

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SYSTEM RIG (DCSS CONFIGURATION)

The objective of this rig is to identify the system response to dynamic (up to 60Hz) excitation and allow a shimmy study(by modelisation).

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OUTCOME OF DRESS

�Specification and design sizing case associated to an electromec hanical steering system

�Electromechanical solution for steering actuation

�Improvement of safety objectives for a steering sys tem (compliance with CATIIIC landings or automatic guid ance system )

�Shimmy damping with an electromechanical actuator

�Control of an active/active redundant actuator

� Use of a distributed architecture for system contro l

�Redundant and fail safe design of all electric airc raft systems

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CONCLUSION

� DRESS solution not optimized for aircraft but generat ing lots of information

� Will enable accurate decisions for design choices on next aircraft generation (New Short Range)

distributed and redundant electro-mechanical nose wheel steering system · 2015. 11. 6. · dress...

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