Status of Handling Qualities Treatment within Industrial ... · Dr. Ing. Christoph Oelker, MET4...

Military Air Systems

Status of Handling Qualities Treatment within Industrial Development Processes and Outlook for Future 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 within Industrial Development Processes and Outlook for Future Needs

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

Dr. Ing. Christoph Oelker, MET4 Flight Test

November 2008


Agenda

Introduction

Handling Qualities (HQ) in Industrial Development Process

HQ Criteria Applied in Industry

Flight Testing of Handling Qualities

Conclusions

Questions


HQ in Industrial Development Process The Role of the FCS

Today 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 envelope and 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


Industrial Development Process

Final AC HQFlight TestCLAW/CP DesignHQ 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


HQ Criteria applied in Industry (1)

Time Response Criteria based on Experience and Experimental Derivation for Design like•

CAP, Frequency and Damping, Pole Criteria

•

Gibson criteria (Dropback Criterion, Tgamma, etc.)Frequency Response Criteria based on simple Pilot Models 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 analysisPilot Opinion – used in manned simulation and flight testing•

Cooper- Harper Rating Scale

•

PIO- Rating Scale



Average Phase Rate Criterion

Flight Path Time Delay Definitions

Relative amplitude limits

100.0

10.0

1.0

0.1

nz / [g / rad]α 1.0 10.0 100.0

ω nα

Level 1

Level 1

Level 3Level 2

Level 2 & 3

Level 2

10.0

3.6

1.0

0.28

0.16

[rad/s]

1.3775

1.8974

0.64

ω 2nα

nz /α

ζ

10.0

3.6

0.28

0.16

0.10

ω 2nα

nz /α

SP

1.3 2.00.25 0.350.01

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)

rela

tive

ope

n lo

op a

mpl

itud

e (d

B)

Θ/

stic

k de

flec

tion

(-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 limits

see 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


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


satisfactory

?

adequate

?

controllable

?

Level 1

Level 2

Level 3

unacceptable


Qualitative Rating – PIO Rating Scale (US Test Pilot School)


6Disturbance or normal control may cause divergent oscillations. Pilot must open control loop by releasing or freezing the stick.

5Divergent oscillations tend to develop when pilot initiates abrupt maneuvers or attempts tight control. Pilot must open loop by releasing or freezing the stick.

4Oscillations 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.

2Undesirable 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.

5Divergent oscillations tend to develop when pilot initiates abrupt maneuvers or attempts tight control. Pilot must open loop by releasing or freezing the stick.

4Oscillations 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.

2Undesirable 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


Flight Testing of Handling Qualities (1)

„Open-Loop“

Tasks

(3211, Pull-up, Push-over, 360°

Roll, Roll Reversals)

„Closed-Loop“, one

Axis

(α

and Nz, Rollangle

or

Heading

Capture, HQDT)

„Closed-Loop“, all Axes

(Formation Flying, AAR, HQDT)

agile Manoeuvring

free

Manoeuvring

opera

tiona

l Rele

vanc

e

Design Relevance

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


•

Phase 1 (Control Law Familiarization)–

Familiarization with Control Law Characteristics

–

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

–

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-Harper Ratings

Flight Testing of Handling Qualities (2)


Experience with the Established Industrial Development Process (1)

Time Response Criteria are easy to handle and successfully provide valid guidelines for design and verification

Frequency Response Criteria for “APC/PIO”- Prevention successfully provide guidelines for clearance and verification

Problems/ Design Iterations, if •

requirements are not adequate/missing

•

models are not adequate or missing


Experience with the Established Industrial Development Process – Problem Examples of the Past/Future Needs (2)

Interface Problem and missing “Pilot as Sensor” - Modelling including Visual system: Deficient Handling due to unchanged HUD- Quickener Design after increasing the aircraft onset

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

Missing/Deficient Pilot Modelling: Roll Ratchet – solved by improved 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 Command Path Scaling

On Ground Tracking Criteria needed


•

Phase 1 open loop testing a necessary step to support system identification/ 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 better methods than HQDT are required

Experience with the Established Industrial Development Process – Flight Test (3)


Summary

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

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

HQ testing inflight covered sufficiently with existing methodology, 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


Questions ?


Backup Folien


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-down Box

Overall satisfactory HQ Evaluations


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)

Am

plitu

deFrequency

mostflying

aggressiveflying


•

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, or Anxiety


30 ft

line of sight

30 ft

line of sight


•

Build-up of HQDT Technique–

Step 1track with non-aggressive,

small Amplitude, low Frequency–

Step 2progress to aggressive low

Amplitude high Frequency–

Step 3increase 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


Am

plitu

de

Frequency

mostflying

aggressiveflying

Step 1 Step 2

Step 3


Experience with PIO Resistance Testing (Phase 2)

•

In accordance with customer requirement “Handling Qualities during Tracking”

(HQDT) method utilised

•

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

Method 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 inputs lead 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 without Problems

•

Formation HQDT difficult to achieve•

Overall PIOR

satisfactory

Status of Handling Qualities Treatment within Industrial ... · Dr. Ing. Christoph Oelker, MET4...

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