Die Die FlugsteuerungFlugsteuerung des Hubschraubers Die ... · Die Flugsteuerung des Hubschraubers...

Ku LX-E 28.10.04 Slide 1 Praxis-Seminar Luftfahrt Proprietary InformationZFLuftfahrtechnik GmbH

Die Flugsteuerung des Hubschraubersvon den Grundlagen bis zur Einzelblattsteuerung

Dr. Oliver KunzeProduktentwicklung LX-EZF Luftfahrttechnik GmbH

Praxis-Seminar LuftfahrtFachhochschule Hamburg

Hamburg, d. 28.10.2004

Die Die FlugsteuerungFlugsteuerung des des HubschraubersHubschraubersvon den von den GrundlagenGrundlagen bisbis zurzur EinzelblattsteuerungEinzelblattsteuerung

Dr. Oliver Dr. Oliver KunzeKunzeProduktentwicklungProduktentwicklung LXLX--EEZF Luftfahrttechnik GmbHZF Luftfahrttechnik GmbH

PraxisPraxis--Seminar Seminar LuftfahrtLuftfahrtFachhochschuleFachhochschule HamburgHamburg

Hamburg, d. 28.10.2004Hamburg, d. 28.10.2004


Helicopter Flight Control – from primary to individual blade control

OverviewOverviewHistory / Configuration and History / Configuration and Performance of a HelicopterPerformance of a HelicopterMain Rotor / Main Rotor Control Main Rotor / Main Rotor Control DesignDesignProblems of the Main Rotor Problems of the Main Rotor

AerodynamicsAerodynamicsVibrationsVibrationsNoiseNoise

Individual Blade Control (IBC)Individual Blade Control (IBC)Principle of OperationPrinciple of OperationEffects in Wind Tunnel and Flight TestsEffects in Wind Tunnel and Flight TestsIBC System DesignIBC System Design

Conclusion and OutlookConclusion and Outlook


Comparison of 1930 Aircraft Maturity, Helicopter vs. Fixed Wing

Do X giant seaplane:MTOW: 48to Distance: 2800km Endurance: 14h

Helicopter by C. d’Ascanio:Altitude: 18m Distance: 1078m Endurance: 8:45min


Helicopter Standard Configuration


Lockheed AH-56A Cheyenne Compound Aircraft


Tiltrotor Aircraft Bell/Boeing V-22 Osprey


Relative Power Required vs. Forward Speed

0

100

200

300

400

0 50 100 150 200

V [m/s]

P/m

[kW

/to]

Helicopter Compound

AirplaneTilt-Rotor


Velocity Distribution over Rotor Disk (Advanced Ratio µ = ΩR / V)


Rotor Blade Lift and Flap


Blade Control System Using a Conventional Swashplate Arrangement

+ϑ

-ϑ


Angle-of-Attack Distribution in Forward Flight

Level Flight


Main Rotor Control SystemEurocopter (MBB) BO105

Primär-steuer,stehend

Taumel-scheibe

Pitch Horn

Steuer-stange


Conventional Mechanical Primary Control System


Main Rotor Sikorsky CH-53G


Main Rotor Sikorsky CH-53G

Primär-steuerBooster

Pitch Horn Steuerstange (hier IBC-Aktuator)

Taumelscheibestehende Schere


Main Rotor Control with SpiderWestland Sea Lynx MK88

Hub

PitchControlRod

SpiderArm

Spindle

Gimbal Joint

RollerBearings


NHI NH-90

Erstflug: 18. Dezember 1995Quadruplex fly-by-wire Steuerung

http://www.nhindustries.com/phot.htm

http://www.nhindustries.com/phot.htm


Main Rotor Design – 1950/60s

AEROSPATIALE AS 341 Sikorsky S-58


Main Rotor Design – Bell 412

Damper andFeather BearingLag Hinge

Virtual FlapHinge


Limiting Phenomena Encountered bya Helicopter Rotor in Forward Flight

Mach Number Effects

Yawed Flow

Reversed Flow

Rotor Wake Interferences

Dynamic Stall Due to Blade Vortex Interaction

High Angles of Attack


Helicopter Vibrations:Source ⇒ Flexible Structure ⇒ Reaction

Periodic and Impulsive Blade Loads

Flexible Rotor/Body Load Paths

Rigid Body MotionsStructural Modes

Flexible BladeCoupledEigenmodes


Vibration Levels of 6 Different Helicopter Types (BO-105 4- and 5-Bladed, CH-53G Aluminium and IRB Blades, Tiger, UH-60)

0.0

0.1

0.2

0.3

0.4

0.5

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45Advance Ratio

n Bl/r

evVi

brat

ion

at P

ilot S

eat [

g]

NASA Recommen-dation

MIL-H-8501A (1962)


Passive Vibration Absorber and Isolation Systems

Cabin AbsorberPendulum Absorber

Nodal BeamIsolation System

FlappingMass

FlexibleLeaf

CabinStructure

Bifilar Absorber

AntiresonanceIsolation System


BVI-Noise Generating Mechanism

Air Flow

Modified Vortex Strength

Reduced Pitch during BVI

ψ = 90°

ψ = 0°


Example of Helicopter Rotor Sound Spectrum (l.h.s.) and Average Time History (r.h.s.)


Individual Blade Control through Blade Rootor Trailing Edge Flap Actuation

Blade RootActuator Electrically

Driven TrailingEdge (Servo) Flap


Individual Blade Control through BladeTwist or Trailing Edge Flap Actuation


IBC Blade Pitch Control with higherharmonic blade pitch movements

0

2

4

6

8

10

12

0 45 90 135 180 225 270 315 360

Rotor Head Azimuth Angle [°]

Bla

de P

itch

[°]

with IBC

primary control

IBC Blade PitchMovementcharacterization:

• frequency (2 .. 7 ΩRotor)

•amplitude (0..3..6°)

• phase (0..360°)


Modification of Local Angle of Attack through IBC

Rotor Azimut Angle ψ [Deg.]

Res

ulta

nt A

ngle

of A

ttack

αre

sat

B

lade

Rad

ial S

tatio

n r/R

= 0

.7

[Deg

.]

with IBC

Baseline

0 90 180 270 360

y

x

r

ψΩ

15

10

5

0

-

-

+

+

++


Principle Layout of IBC System

BLADE-ROOT IBCPITCH ACTUATORS

HYDRAULICPOWER PICK-UP

HYDRAULICMANIFOLD,

MONITORINGAND SHUT-OFF

A

B

ELEC. & HYDRAUL.ROTARY TRANSMISSION

CONVENTIONALFLIGHT CONTROL

SYSTEM

DIGITALCOMPUTER

HYDRAULICDISTRIBUTION

FEEDBACKSIGNALS

CONTROLPANEL

IBC POSITIONCOMMANDS


IBC Actuator Mounted between Swashplate and Blade Pitch Horn Replacing the Rigid Pitch Rod


Full Scale UH-60 Rotor Wind TunnelTests conducted at NASA Ames


IBC Inputs and Test Conditions


Large Wind Tunnel at NASA Ames Research Center


Testbed BO-105 S1 with IBC System


IBC Testbed CH-53G 84+02 Operated by WTD 61


Dynamic Components with IBC Mock-Up


IBC Data Processing and Control Computer (ZFL) and Data Gathering System (WTD 61)


Effect of 0.15deg 5/rev IBC on 6/rev Accelerations at Main Gear Box and Pilot Seat @120kts

x y z

x y z

Pilot Seat

MGB


Effect of 0.15deg 5/rev IBC on z-Vibration Spectrumat Pilot Seat @120kts

without IBC

with IBC


C.L. Test Sequence @70kts, Single Mode 5/rev IBC Controlled Variable: 6/rev AccPilz

CL

OLPhaseSweep

90%

refrefref

ref


Predicted Multi Harmonic Vibration Reduction at Main Gear Box Based on Single Harmonic Flight Test Data (0.15deg IBC at 90kts)

G(AccHGx,AccHGy,AccHGz)

100

Vib

ratio

n R

educ

tion

[%]

Numerically Predicted 6/rev Vibration Reduction at Main Gear Box (All Three Axes) Due to Different IBC Frequency Combinations

80

60

40

20

06/rev 4, 6/rev 4, 6, 7/rev 4, 5, 6, 7/rev

0.35

Req

uire

dA

mpl

itude

s[d

eg]

0.30

Corresponding Amplitudes Required0.25

0.20

0.15

0.10

0.05

0.006/rev 4, 6/rev 4, 6, 7/rev 4, 5, 6, 7/rev


Noise Reduction Due to 2/rev 0.66deg IBC at Three Microphones (65kts, -6deg, Optimum IBC Phase)

1031009794918885

Mic #2 (Retr. Side)

1031009794918885

Mic #1 (Center)

VIAS = 65kts, γ = -6°N

on-c

orre

cted

Sou

nd P

ress

ure

Leve

l[dB

]

1031009794918885

Mic #3 (Adv. Side)

-10 -8 -6 -4 -2 0 2 4 6 8 10

Time [sec] (t=0 at moment of highest sound pressure level)

Reference, no IBCA2 = 0.67°, ϕ2 = 30°


Flight Performance Relevant Parameters During 2/rev IBC Phase Sweep

4500

4000

3500Alti

tude

[ft]

#1 #2 #3 #4 #5 #6 #7 #8Data Points

16 Revs≈ 5 sec

135

130

125

120VIA

S [k

ts]

Level Flight VIAS = 125kts, A2 = 0.67°w/o IBC ϕ2 = 0° = 60° = 120° = 180° = 240° = 300° = 359°

2600

2500

2400

2300

Pow

erQ

·Ω[k

W]


Effect of 2/rev 0.66deg IBC on Power Required (125kts, Net Effect, Corrected by Speed, Accel. and Heave Effects)

IBC Phase Angle

-15.00

-10.00

-5.00

0.00

5.00

10.00

15.00

0 60 120 180 240 300 360

ϕ 2 [°]

∆P

[%] (

corr

ecte

d)

More Power Required

Less Power Required


Reduction of Pitch Link / Actuator Load by Application of Optimum Phase 2/rev IBC (A2 = 0.66° ϕ2 = 270°)


Integration of IBC-System into CH-53G Testbed


ZFL´s IBC Actuator Evolution

TSS

BO 105 F/T

UH-60A WT/T

CH-53G F/T

BO 105 WT/T


CH-53G IBC Experimental System Actuator Design


IDS IBC DC test bench with reversedkinematics non rotating ↔ rotating

11 kW electrical drive

electrical slip ring

torque/speed sensor

hydraulic manifold

4 IBC actuators

IBC DC pump

pump control unitin drive cage


Adaptation of Existing IDS to Lynx Rotor Hub


InHuS: Innovative Integrated Primary and Individual Blade Control System for Helicopters

IDS:Integration of BothPrimary Control andIBC intoGearbox/Rotorhub

IBC:Hydraulic and ElectricalIndividual Blade Control Systems withHigh Bandwidth butLow Authority

InHuS:Control System in theRotating Frame at Blade Root, Combining BothPrimary Control and IBC Using One Actuation System


InHuS: Innovative Integrated Primary and Individual Blade Control System for Helicopters (preliminary design)


Conclusion

Helicopter versatile aircraftHelicopter versatile aircraftComplex aerodynamics of main rotor in Complex aerodynamics of main rotor in forward flight causes performance forward flight causes performance restrictionsrestrictionsadvanced main rotor blade control can advanced main rotor blade control can reduce reduce vibationvibation & noise and extend flight & noise and extend flight envelopeenvelopeextensive research work on IBC effects extensive research work on IBC effects has been donehas been doneworldworld--wide development wide development activitesactivites of the of the helicopter industry in the field of helicopter industry in the field of application to production helicoptersapplication to production helicopters

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