control the rascal juh-60a in-flight simulatorrascal … acg 102 fl… · 1 control the rascal...

1

UH-60M Upgrade Fly-By-Wire Flight Control Risk Reduction Using the

RASCAL JUH-60A In-Flight Simulator

UH-60M Upgrade Fly-By-Wire Flight Control Risk Reduction Using the

RASCAL JUH-60A In-Flight Simulator

Jay FletcherJeff Lusardi

Hossein MansurErnie Moralez

LTC Dwight RobinsonAeroflightdynamics

Directorate (AMRDEC)U.S. Army RDECOM

Ames Research CenterMoffett Field, CA

Dave ArterburnU.S. Army

Utility Helicopters Program OfficeRedstone Arsenal, AL

Chan MorseMorse Flight Test

San Diego, CA

Igor CherepinskyJoe Driscoll

Sikorsky Aircraft CorporationStratford, CT

Kevin KalinowskiPerot Systems Government Services

Ames Research CenterMoffett Field, CA

DISCLAIMER: Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not constitute or imply its endorsement, recommendation, or favoring by the United States Government. The views and opinions of the authors expressed herein do not necessarily represent or reflect those of the United States Government, and shall not be used for advertising or product endorsement purposes.Approved for public release; distribution unlimited. Review completed by the AMRDEC Public Affairs Office (14 Feb 2008 and FN 3445).

2

OutlineOutline

•

Background and motivation•

UH-60M Upgrade fly-by-wire flight control system

•

UH-60M Upgrade risk reduction development•

Handling Qualities evaluation

•

Conclusions

3

UH-60M Upgrade Fly-By-Wire Flight Control System

UH-60M Upgrade Fly-By-Wire Flight Control System

Fly-By-Wire

Key Components

Main Rotor Servo Actuatorand Tail Rotor Actuator

Active Conventional Controllers

Flight Control Computer

Before After

•

Requirements–

Level I Handling Qualities in GVE and DVE (per ADS-33)

–

Agility and maneuverability (ORD para

4.5.d)

•

Benefits–

Improved safety & survivability •

Reduced pilot workload / improved HQ•

Reduced vulnerable area–

Weight reduction –

improved lift & range–

Reduced O&S cost –

fewer critical parts–

Task Tailored control laws

•

System Description–

Triple redundant full authority system–

Advanced control law implementation–

Conventional control and pedal locations with active feedback

–

Tactile Cueing for Envelope Limiting–

Automatic flight control mode switching–

Selectable coupled Flight Director modes

4

Explicit Model Following Architecture

Explicit Model Following Architecture

•

Aircraft response follows simple, low-order command model–

Command model has known good response characteristics–

Command model can be scheduled to implement task-tailoring•

Forward Path–

Aircraft dynamics approximately cancelled by low-order inverse plant•

Feedback Path–

Compensation for imperfect plant dynamics cancellation–

Provides disturbance rejection, performance robustness, and stability

5

UH-60M Upgrade Control Law Modes UH-60M Upgrade

Control Law Modes

10050

“B l ended ” Spe ed , k t s

Vy

40

520

Low Speed Turn Coordination

Response Types & Control Modes

Axis Command Hold

Pitch Att

/ Acc Velocity

Roll Att

/ Acc Velocity

Yaw Yaw Rate Heading

Vertical Climb Rate Altitude

Axis Command Hold

Pitch Att

/ Acc Position

Roll Att

/ Acc Position


Vertical Climb Rate Altitude

Low Speed


Hover / Near Hover


High Speed


Axis Command Hold

Pitch Att

/ Acc Velocity

Roll Attitude Attitude


Vertical Flight Path Flight Path

Low Speed / High Speed Hysteresis Region

Sideslip Envelope Protection (Passive)

Full Pedal Command=

Max Sideslip

Axis Command Hold

Pitch Att

/ Acc Velocity

Roll Attitude Attitude

Yaw Sideslip Turn Coord

Vertical Flight Path Flight Path

6

UH-60M Upgrade Risk ReductionUH-60M Upgrade Risk Reduction

•

Objective: Accelerate UH-60M Upgrade FCS design maturity by getting to flight as soon as possible

•

Approach–

Fly key FCS elements on the RASCAL JUH-60A before the prototype UH-60M Upgrade

–

Leverage AFDD flight control design, analysis, simulation, and optimization tools

–

Develop and evaluate UH-60MU system performance on RASCAL

7

Control Laws• Architecture• Gains• Modes

Requirements• AVNS-PRF-10018• ADS-33E-PRF• MIL-F-9490

Math Models• Gen Hel• FORECAST• CIFER SYS ID




AFDD Flight Control Rapid Prototyping Process

AFDD Flight Control Rapid Prototyping Process

•

Developed to meet S&T goals for reducing FCS development time•

Readily applied to UH-60M Upgrade FCS risk reduction development

8

RASCAL JUH-60ARASCAL JUH-60A

Research Flight Control System (RFCS) •

Fail/Safe architecture •

Programmable displays •

Active inceptors •

Telemetry

9

Flight Mechanics ModelingFlight Mechanics Modeling







10

Model Development & ValidationModel Development & Validation

•

Objectives–

Validation for RASCAL (UH-60A) Update legacy models for UH-

60MU

–

Validation for UH-60MU

•

Applications–

FC design and optimization–

Piloted and HWIL simulation–

UH-60A and UH-60M–

Sikorsky and Army•

Types–

Non-linear full-flight-envelope–

Linearized

FFE models–

Identification models

11

-40

-20

0

20

Mag

nitu

de (d

B)

Flight

Gen Hel (DF)

FORECAST

-540

-450

-360

-270

-180

Phas

e (d

eg)

10-1 100 101 102

0.2

0.6

1

Frequency (rad/sec)

Coh

eren

ce

-40

-20

0

20

Mag

nitu

de (d

B)

-270

-180

-90

0

90

Phas

e (d

eg)

10-1 100 101 102

0.2

0.6

1

Frequency (rad/sec)

Coh

eren

ce

Math Model Fidelity (Bare Airframe)

Math Model Fidelity (Bare Airframe)

•

Model Types–

Gen Hel –

Non-linear, full flight envelope simulation model

–

FORECAST –

Linearized

extraction from Gen Hel

•

Generally Good Fidelity•

Deficiencies–

Lead-lag mode frequency–

Directional response to pedals

Pitch Rate / Lon Cyclic Yaw Rate / Pedals

12

UH-60A vs. UH-60M Flight Dynamics (Bare Airframe) UH-60A vs. UH-60M Flight Dynamics (Bare Airframe)

UH-60M JUH-60A

Rotor Blades Wide Chord Narrow Chord

Engines GE-T700-701D GE-T700-700

-20

0

20

40

Mag

nitu

de (d

B)

Roll Rate due to Lateral Cyclic

UH-60MJUH-60A

-540

-360

-180

Phas

e (d

eg)

10-1 100 101 102

0.2

0.6

1

Frequency (rad/sec)

Coh

eren

ce

-20

0

20

40Yaw Rate due to Pedals

-180

0

180

10-1 100 101 102

0.2

0.6

1

Frequency (rad/sec)

Dynamic Comparison•

All on and off-axis responses to cyclic and pedals are very similar

•

Vertical acceleration response to collective shows largest difference

Major Configuration Differences

-20

0

20

40Vertical Acceleration due to Collective

-360

-180

0

10-1 100 101 102

0.2

0.6

1

Frequency (rad/sec)

13

Control Law AnalysisControl Law Analysis







14

Control Law Analysis and Optimization with CONDUIT®

Control Law Analysis and Optimization with CONDUIT®

•

Powerful Multi-Objective optimization engine enables CONDUIT®

•

Control system defined as SIMULINK®

block diagram–

139 states for UH-60MU

•

Linked with linear Aircraft model in SIMULINK®

–

25 state FORECAST model for hover

•

“Design Parameters”

selected for manual or automatic tuning

–

35 for UH-60MU hover/low speed

•

Key CONDUIT®

specs –

57 specs evaluated for UH-60MU–

e.g. ADS-33, MIL-F-9490

!

Challenging Optimization Problem!

System

Airframe Model

Flight Control Engineer

Controller Structure

Design SpecsOptimization

(tuning)

Simulation

CONDUIT

Eval

uatio

n

Tran

slat

ion

15

CONDUIT® Predicted PerformanceCONDUIT® Predicted Performance

Specs: 57 Dps: 35 States (simplified case): 139

Level 1

Level 2

Level 3

Pitch

Roll

Yaw

0 10 200

20

40

60

80

GM (dB)

PM (d

eg)

StbDaG1:Frequency Sweep Spec

Ames Research Center

HACAH USING FLT DATA

0 10 200

20

40

60

80

GM [db] PM

[deg

]

(rigid-body freq. range)StbMgG1: Gain/Phase Margins

MIL-F-9490D

HINNER, ACVH OUT OF DE

0 10 200

20

40

60

80

GM [db]

PM [d

eg]

(rigid-body freq. range)StbMgG1: Gain/Phase Margins

MIL-F-9490D

HINNER, POSITION

0 2 40

0.1

0.2

0.3

0.4

Bandwidth [rad/sec]

Phas

e de

lay

[sec

]

Other MTEs;UCE>1; Div AttBnwAtH1:Bandwidth (pitch & roll)

ADS-33D

SACAH

0 2 40

0.1

0.2

0.3

0.4

Bandwidth [rad/sec]

Phas

e de

lay

[sec

]

Other MTEs (Yaw)BnwYaH2:BW & T.D.

ADS-33D

SRCHH Yaw

0 0.5 11

1.2

1.4

1.6

1.8

2

Bandwidth [rad/sec]

(linear scale)DstBwG1:Dist. Rej. Bnw

SACAH, THETA

0 1 21

1.2

1.4

1.6

1.8

2

Bandwidth [rad/sec]


SACAH, PHI

0 1 21

1.2

1.4

1.6

1.8

2

Bandwidth [rad/sec]


SRCHH, PSI

0 100 2000

0.2

0.4

0.6

0.8

1

Total Cost

ModFoG2:Cost PointSACAH

0 1 20

0.2

0.4

0.6

0.8

1

Actuator RMS

RmsAcG1:Actuator RMS

Ames Research Center

JACAH

-40 -20 0-40

-30

-20

-10

0

10

Average q/p (dB)

Aver

age

p/q

(dB)

Frequency DomainCouPRH2:Pitch-Roll Coupling

ADS-33E

CACAH

-1 0 10

0.2

0.4

0.6

0.8

1

r3/hdot(3) [deg/ft] r1

/hdo

t(3)

[deg

/ft]

Yaw/CollectiveCouYaH1:Coupling

ADS-33D

CACVH

16

System VerificationSystem Verification







17

CONDUIT® Flight Test

Longitudinal

wc 3.5 3.5

PM 49.7 48.4

GM 13.5 8.5

Lateral

wc 4.2 3.4

PM 50.3 51.8

GM 8.1 7.3

Directional

wc 5.7 6.2

PM 31.1 45.5

GM 8.2 6.7

Vertical

wc 1.9 1.6

PM 74.6 64.5

GM 8.9 9.7

CLAW Integration VerificationCLAW Integration Verification

Longitudinal Broken Loop(From Injected Sweeps)

Longitudinal Forward Loop(From Piloted Sweeps)

•

Excellent agreement between analysis and test•

Minor discrepancies associated with known model shortcomings

-40

-20

0

20

Mag

nitu

de (d

B)

-360

-270

-180

-90

0

Phas

e (d

eg)

10-1 100 101 102

0.2

0.6

1

Frequency (rad/sec)

Coh

eren

ce

-40

-20

0

20

40

Mag

nitu

de (d

B)

FlightCONDUIT

-360

-270

-180

-90

0Ph

ase

(deg

)

10-1 100 101 102

0.2

0.6

1

Frequency (rad/sec)

Coh

eren

ce

18

-40

-20

0

20

Mag

nitu

de (d

B)

-360

-180

0

Phas

e (d

eg)

Baseline Gains, FlightBaseline Gains, FORECASTReduced Gains, Flight

10-1 100 101 102

0.2

0.6

1

Frequency (rad/sec)

Coh

eren

ce

Lead-Lag Mode StabilityLead-Lag Mode Stability

•

Initial CONDUIT®

optimization–

FORECAST aircraft model–

Adequate stability margins–

Known lead-lag mode errors

•

Pitch/Roll oscillations when velocity/accel

loops closed–

Replace q/lon

with flight test measured frequency response

–

Low gain margin (~4dB) at progressing lead-lag frequency

•

Final CONDUIT®

Optimization–

Substantial stability increase (12dB)–

Other performance unchanged

•

Stability improvement verified in flight

Pitch Rate / Longitudinal Cyclic

~4dB16dB

34r/s

19

Flight Test EvaluationFlight Test Evaluation







20

Handling Qualities EvaluationHandling Qualities Evaluation

•

Quantitative Assessment–

Predicted handling qualities criteria from ADS-33–

Frequency sweeps, steps, etc…

•

Qualitative Assessment–

Five ADS-33 Mission Task Elements (MTE):•

Precision Hover•

Hovering Turns•

Lateral Reposition•

Depart / Abort•

Vertical Maneuver–

Five evaluation pilots (2 Sikorsky, 3 Army)–

EH-60L served as baseline for comparison–

GVE and simulated DVE evaluation flights in both aircraft

–

DVE simulated with modified NVGs

(UCE=2+)

•

Data collected–

Performance data and time histories (aircraft, control system, GPS, etc…)

–

Cooper-Harper handling qualities ratings (HQR) and commentary

21

Quantitative CriteriaQuantitative Criteria

1 2 3 4 50

0.1

0.2

0.3

0.4

Level 3

Level 2

Level 1

!p"!p#(sec)

$BW ", $BW

# (rad/sec)

Pitch Disp Pitch Disp CONDUITPitch Force Roll Disp Roll Disp CONDUIT Roll Force

1 2 3 4 50

0.1

0.2

0.3

0.4

Level 3

Level 2

Level 1

!p%

(sec)

$BW % (rad/sec)

Yaw Disp Yaw Disp CONDUIT

0 1 2 3 4 5 6-50

0

50

100

150

200

Time (sec)

Clim

b R

ate

(ft/m

in)

hhe

48

49

50

51

52

53

Col

lect

ive

(%)

Collective

10.5

122.0

&'

sKeh s

col

est

(

!

Level 1 for all criteria evaluated

0 10 20 300

1

2

q pk/ )# p

k (1/s

ec)

Minimum attitude change, )qmin (deg)

Level 1

Level 2

ForwardAft

0 20 40 600

1

2

p pk/ )" p

k (1/s

ec)

Minimum attitude change, )qmin (deg)

Level 1

Level 2

Level 3

Left Right

22

Mission Task Element

Hover

Hov Turn

R

Hov Turn

L

Lat R

epo R

Lat R

epo L

Dep Abo

rt

Vert M

an


Hover

Hov Turn

R

Hov Turn

L

Lat R

epo R

Lat R

epo L

Dep Abo

rt

Vert M

an1

2

3

4

5

6

7

8

9

10


Hover

Hov Turn

R

Hov Turn

L

Lat R

epo R

Lat R

epo L

Dep Abo

rt

Vert M

an

Han

dlin

g Q

ualit

ies

Rat

ing

Handling Qualities Ratings (GVE)Handling Qualities Ratings (GVE)

UH60MU / RASCALAvg GVE HQR = 2.8

EH-60LAvg GVE HQR = 4.3

UH-60A (1999)Avg GVE HQR = 4.2

•

UH-60MU provides average of 1.5 HQR improvement over EH-60L•

EH-60L baseline agrees well with 1999 UH-60A evaluation

23


Hover

Hov Turn

R

Hov Turn

L

Lat R

epo R

Lat R

epo L

Dep Abo

rt

Vert M

an


Hover

Hov Turn

R

Hov Turn

L

Lat R

epo R

Lat R

epo L

Dep Abo

rt

Vert M

an

Handling Qualities Ratings (DVE)Handling Qualities Ratings (DVE)

1

2

3

4

5

6

7

8

9

10


Hover

Hov Turn

R

Hov Turn

L

Lat R

epo R

Lat R

epo R

Dep Abo

rt

Vert M

an

Han

dlin

g Q

ualit

ies

Rat

ing

UH60MU / RASCALAvg GVE HQR = 2.8

UH60MU / RASCALAvg DVE HQR = 3.2

EH-60LAvg DVE HQR = 5.2

•

UH-60MU provides average of 2 HQR improvement over EH-60L in DVE–

Hold modes provide significant workload reduction–

Smaller degradation in DVE (1/2 HQR) than EH-60L (1 HQR)

24

ConclusionsConclusions

•

UH-60M Upgrade control laws provide significant improvements in hover and low speed handling qualities relative to the UH-60A/L baseline

•

AFDD flight control rapid prototyping tools provide a highly effective means to analyze and optimize sophisticated multi-mode fly-by-wire flight control systems

•

Math models used in flight control analyses and optimization for

fly-by-wire flight control design must accurately represent the lead-lag dynamics to ensure satisfactory stability margin estimates

•

RASCAL JUH-60A flight dynamics are representative of the UH-60M

•

RASCAL development phase for the UH-60M Upgrade FBW FCS has significantly reduced risk for the program

control the rascal juh-60a in-flight simulatorrascal … acg 102 fl… · 1 control the rascal...

Documents