03-R Osterhuber DGLR HQ Workshop 081112

7/30/2019 03-R Osterhuber DGLR HQ Workshop 081112

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Military Air Systems

Status of Handling Qualities Treatment withinIndustrial Development Processes and Outlook forFuture Needs

Dipl. Ing. R. Osterhuber, Dr. Ing. M. Hanel, MEA25 Flight Control

Dr. Ing. Christoph Oelker, MET4 Flight Test

November 2008

Status of Handling Qualities Treatment withinIndustrial Development Processes and Outlook forFuture Needs

Dipl. Ing. R. Osterhuber, Dr. Ing. M. Hanel, MEA25 Flight Control

Dr. Ing. Christoph Oelker, MET4 Flight Test

November 2008


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Agenda

Introduction

Handling Qualities (HQ) in Industrial Development Process

HQ Criteria Applied in Industry

Flight Testing of Handling Qualities

Conclusions

Questions


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HQ in Industrial Development Process

The Role of the FCSToday Handling Qualities are nearly completely defined by the

Flight Control Laws

New features like auto trim in all axes and carefree are provided

Handling Quality Design via Flight Control Laws allows to

normalize Handling Qualities over the whole flight envelopeand configurations

to optimise Ride Qualities (via feedback loops) and Handling

Qualities (via Command Path) separately

to optimise for different tasks which are

o

flight path control driven (cross acquisition, AAR, TOL, formation flying)

o

nose angle driven

fine tracking


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Industrial Development Process

Final AC HQFlight TestCLAW/CP Design

HQ Requirements

Cockpit Controls/SSICAVisuals (HUD, HDD)

L1

L2

. ..

. . K P..

..

.

.

.

.Tef .

Requirements wrong

Design not accurate/ models not exact

Design not accurate/ models not exact

Undesired interaction


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HQ Criteria applied in Industry (1)

Time Response Criteria based on Experience andExperimental Derivation for Design like

CAP, Frequency and Damping, Pole Criteria

Gibson criteria (Dropback Criterion, Tgamma, etc.)

Frequency Response Criteria based on simple PilotModels for APC/PIO- prevention

Gibson -Spider and related criteria (phase rate criterion,

relative/absolute amplitude, etc.)

Neal-Smith

OLOP - criterion

Second order (PT2) for roll ratchet analysis

Pilot Opinion used in manned simulation and flighttesting

Cooper- Harper Rating Scale

PIO- Rating Scale


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Average Phase Rate Criterion

Flight Path Time Delay Definitions

Relative amplitude limits

100.0

10.0

1.0

0.1

nz / [g / r ad]

1.0 10.0 100.0

n

Level1

Level1

Level3

Level 2

Level2

&3

Level2

10.0

3.6

1.0

0.28

0.16

[rad/s]

1.3775

1.8974

0.64

2

n

nz/

10.0

3.6

0.28

0.16

0.10

2

n

nz/

SP

1.3 2.00.25 0.35

0.01

1.0

L1

L2-25

-20

-15

-10

-5

0

5

10

15

20

25

-180 -160 -140 -120 -100 -80 -60 -40

open loop phase (deg)

relativeopenloopamplitude(dB

)

/stickdeflection

(-150, 1 dB)

(-180, 1.5 dB)

L3

L1

(-140, 2 dB)

L2(-75, 10dB)

(-100, 6 dB)

(-80, 16 dB)

(-85, 2 dB)

(-75, 4 dB)

L2

A (-110, 0 dB)

(-80, -2 dB)(-55, 0 dB)

L1(-100, 18 dB)

(-45, 0 dB)

*-45, 6 dB

* For applicability limitssee 3.2.2.1.4.

*

*

0

50

100

150

200

250

0 0.5 1 1.5

ellipses

(0.3, 60)

(0.375, 50)

(0.5, 40)

(0.66, 85)

(0.7, 145)

(0.8, 195)

Level 1

Level 2

Level 3


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Qualitative RatingHandling Qualities Rating Scale (Cooper-Harper, NASA 1969)


satisfactory

?

adequate ?controllable

?

Level 1

Level 2

Level 3

unacceptable


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Qualitative Rating PIO Rating Scale (US Test PilotSchool)


6Disturbance or normal control may cause divergent oscillations.

Pilot must open control loop by releasing or freezing the stick.

5

Divergent oscillations tend to develop when pilot initiates abrupt maneuvers or

attempts tight control.Pilot must open loop by releasing or freezing the stick.

4

Oscillations tend to develop when pilot initiates abrupt maneuvers or attempts

tight control.

Pilot must reduce gain or abandon task to recover.

3

Undesirable motions easily induced when pilot initiates abrupt maneuvers or

attempts tight control.These motions can be prevented or eliminated, but only at sacrifice to task

performance or through considerable pilot attention and effort.

2

Undesirable motions tend to occur when pilot initiates abrupt maneuvers or

attempts tight control.

These motions can be prevented or eliminated by pilot technique.

1No tendency for pilot to induce undesirable motion.

PIORDescription

6Disturbance or normal control may cause divergent oscillations.

Pilot must open control loop by releasing or freezing the stick.

5

Divergent oscillations tend to develop when pilot initiates abrupt maneuvers or

attempts tight control.Pilot must open loop by releasing or freezing the stick.

4

Oscillations tend to develop when pilot initiates abrupt maneuvers or attempts

tight control.

Pilot must reduce gain or abandon task to recover.

3

Undesirable motions easily induced when pilot initiates abrupt maneuvers or

attempts tight control.These motions can be prevented or eliminated, but only at sacrifice to task

performance or through considerable pilot attention and effort.

2

Undesirable motions tend to occur when pilot initiates abrupt maneuvers or

attempts tight control.

These motions can be prevented or eliminated by pilot technique.

1No tendency for pilot to induce undesirable motion.

PIORDescription


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Flight Testing of Handling Qualities (1)

Open-Loop

Tasks

(3211, Pull-up, Push-over, 360 Roll, Roll Reversals)

Closed-Loop, one

Axis

( and Nz, Rollangle or Heading Capture, HQDT)

Closed-Loop, all Axes

(Formation Flying, AAR, HQDT)

agile Manoeuvring

free Manoeuvring

operati

onal

Relev

ance

DesignR

elevance

Wichmann et al.: High-Alpha

Handling Qualities

Flight

Research on the

NASA F/A-18 High Alpha Research Vehicle,

NASA-TM-4773, 1996

Phase 1

Phase 2

Phase 3


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Phase 1 (Control Law Familiarization)

Familiarization with Control Law Characteristics

Low Gain open and 1 axis Closed Loop Tasks (no HQ Ratingsrequired)

Efficient Approach of early Identification of Control Law Snags

Phase 2 (PIO Resistance Testing and PIO Ratings)

Application of Handling Qualities During Tracking

(HQDT)

Technique

Attitude Capture HQDT, Formation Flying HQDT,Target Tracking HQDT, Air-to-Air Refueling (Basket Tracking HQDT)

Phase 3 (Operational Handling Qualities Testing)

Closed Loop Testing

Clinical Attitude Captures, Formation Flying, Offset Landings,

Air-to-Air Refueling, Air-to-Air Tracking

Tasks with well defined Performance Criteria Cooper-HarperRatings

Flight Testing of Handling Qualities (2)


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Experience with the Established IndustrialDevelopment Process (1)

Time Response Criteria are easy to handle andsuccessfully provide valid guidelines for design andverification

Frequency Response Criteria for APC/PIO- Preventionsuccessfully provide guidelines for clearance and

verification

Problems/ Design Iterations, if

requirements are not adequate/missing models are not adequate or missing


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Experience with the Established Industrial DevelopmentProcess Problem Examples of the Past/Future Needs (2)

Interface Problem and missing Pilot as Sensor - Modellingincluding Visual system: Deficient Handling due to unchangedHUD- Quickener Design after increasing the aircraft onset

Criteria of Display Dynamics as function of aircraftagility (i.e. Tgamma) needed

Missing/Deficient Pilot Modelling: Roll Ratchet solved byimproved modelling and Command Path Redesign

Further Improvement of Modelling neededMissing/Conflicting Criteria/Missing Pilot Models:

Agility/Tracking

Big Amplitude Criteria needed, HQ boundaries for

different pilot technique (High/Low Gain Pilots)Missing Requirements: Handling during Aerobraking

Dropback Problem had to be solved via On-Ground CommandPath Scaling

On Ground Tracking Criteria needed


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Phase 1 open loop testing a necessary step to support systemidentification/ model estimation

Phase 2 PIO resistance testing essential to prove robustness of

pilot-aircraft system before testing operational HQ

Experience with HQDT

not always satisfactory as high gain/ high amplitude

inputs lead to reduction of pilot bandwidth

More appropriate testing methodology for industrial environment required

Phase 3 operational testing successfully performed in various tasks

satisfactory results

results consistent with phase 2 results

FQ/ HQ testing covered sufficiently with existing methodology,except HQDT

For clinical high gain/ high amplitude pilot-in-the-loop-testing bettermethods than HQDT are required

Experience with the Established Industrial

Development Process Flight Test (3)


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Summary

A well defined development process w.r.t HQ exists in industry

Available HQ criteria based on experience and simple pilotmodels successfully provide design and clearance requirements

HQ testing inflight covered sufficiently with existingmethodology, except HQDT

In some areas (roll ratchet, display dynamics, pilot technique)better (pilot) modelling required

In some areas (big amplitude maneuvring, pilot technique)accurate/new requirements would reduce design iterations


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Questions ?


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Backup Folien


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Overview of Results on Closed Loop HQ Testing(Phase 3)

Formation Flying

crisp precise Aircraft Response

Control Sensitivity in Pitch and Roll satisfactory

Air-to-Air Tracking fine Tracking Stick Freeze Exercise

for low Gain

Pilots

high Gain Pilots need Compensation

Air-to-Air Refueling very much alike flying in close Formation

crisp Aircraft Response well liked

Hook-up Rates (successful hook-ups vs. total

attempts) greater 80%

Offset Landings

precise and predictable within desired Touch-downBox

Overall satisfactory HQ Evaluations


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PIO Resistance Testing (1)

(Handling Qualities During Tracking Technique)

Normal Pilot Tracking Technique

no adverse conditions

adopt lowest Gain

Consistent with reasonable

Task Performance

Special

Conditions

Stress, Excitement, Anxiety

high Gain Technique

aggressive Inputs/ Flying

Purpose of PIO Resistance Testing

detect HQ Deficiencies in Flight Test before In-Service Flying

expose potentially hazardous Characteristics in safe Environment

deliberately drive Pilots to make aggressive but controlled Inputs

Key Objective of Handling Qualities During Tracking (HQDT)

Amp

litude

Frequency

most

flying

aggressive

flying


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Definition of HQDT Tasks

Horizon Tracking (longitudinally, laterally,

various Attitude Off-sets)

Wind-up-Turn Tracking

(50 mils Off-set) Formation Flying Tracking (attain Zero Tracking Error)

Air-to-Air Refueling Basket Tracking

Distinctive Requirement of HQDT Piloting Technique

track Precision Aim as aggressively and as attentively as possible correct the smallest Tracking Error as rapidly as possible

Expected Result

Increase of Pilot Bandwidth (Pilot injected Frequency Spectrum)

emulate Pilot Control Strategy when experiencing Stress, Fear, orAnxiety

PIO Resistance Testing (2)(Handling Qualities During Tracking Technique)

30 ft

line of sight

30 ft

line of sight


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Build-up of HQDT Technique

Step 1

track with non-aggressive,

small Amplitude, low Frequency

Step 2

progress to aggressive low

Amplitude high Frequency

Step 3

increase Amplitude at high

Frequency until bang-bang Control is achieved

applicable Performance Measure always minimum Tracking Error

Pilot evaluation with qualitative comments and PIO

ratings for each

step

PIO Resistance Testing (3)(Handling Qualities During Tracking Technique)

Am

plitude

Frequency

most

flying

aggressive

flying

Step 1 Step 2

Step 3


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Experience with PIO Resistance Testing

(Phase 2)

In accordance with customer requirement Handling Qualitiesduring Tracking (HQDT) method utilised

Aim is to challenge pilot-aircraft-system in flight with high gain/ high

amplitude tasksMethod well known from USAF

Test Pilot School

HQDT method divided into 3 steps (Build-up of Complexity) Step 1 and Step 2 with low and high frequency small amplitude inputslead to expected increased pilot bandwidth

Step 3 (high frequency and high amplitude) lead to Bang-Bang

type

inputs with reduction of pilot bandwidth (not fully understood yet)

Step 3 increase of bandwidth by minor pilot compensation/ anticipation

Attitude, 3g Tracking HQDT, and AAR HQDT performed withoutProblems

Formation HQDT difficult to achieve

Overall PIOR satisfactory

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03-R Osterhuber DGLR HQ Workshop 081112