MAV activities in flight dynamics and control

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Prof A.V. Efremov, Ph. D., D. of Sc.,The Head of Flight Dynamics and Control Department,

Moscow Aviation Institute

97 SAE Aerospace Control and Guidance Systems Committee Meeting

Lake Tahoe, NevadaMarch, 2006

1. Flying qualities evaluation in different piloting tasks.

2. Manual control for ESTOL.

3. Micro aerial vehicle dynamics, flight control and design.

4. Pilot behavior modeling.

RESEARCHES 2005

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• Improvement of agreement between in-flight and ground based simulations;

• Development of data base on ground based evaluation of Flying Qualities for the further researches in manual control area;

• Development of technique for ground based simulation accompanying in-flight evaluation of Flying Qualities;

• Determination of the factors defined pilot rating.

FLYING QUALITIES EVALUATION

Goals of investigations

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• Landing;

• ESTOL;

• Aim-to-aim tracking;

• Formation flight;

• Refueling.

INVESTIGATED PILOTING TASKS

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• selection of dynamic configurations;

• definition of task performances (desired, adequate) and additional variables (conditions for stress situations, number of attempts in each experiment, etc);

• generation of input signal;

• development of questionnaire for each piloting task;

• data reduction.

The stages for flying qualities investigationsin each piloting task

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Table of all experimental researches

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Piloting task Configurations Number of experiments Comment

Landing31 (including HAVE PIO, LAHOS and others)

1185171 experiments with side stick. 3 landings in each experiment.

Refueling29 (including HAVE GAS, Neal-Smith and others)

263 3 – 11 attempts in each experiment.

Aim-to-aim tracking 11 (Neal-Smith) 68

Formation flight 31 66

Aim-to-aim tracking tasks (on workstation) 42 534 84 experiments with

the motion cues.

ESTOL 5 91Configurations differ by level of augmentation

Total: 2060(> 6200 runs)

At least 3 runs in each experiment

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DEFINITION OF TASK PERFORMANCES

Refuelingpercentage of successfulattempt (desired, adequate)

Landing (desired, adequate)

hAir-to-air trackingaccuracy (desired, adequate)

mrad ,

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GENERATION OF INPUT SIGNAL

Math model of drogue motion Data reduction

development of spectrum and its approximation

ΔХ

ΔZ Video tape

recording of the real drogue

motion

tAlk

lklk,

,, sin

Refueling

9REFUELING

AIR-TO-AIR TRACKING10

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QUESTIONNAIRE (pilot comment card)

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Correlation of pilot rating PR with max PR of FQ in longitudinal ( ) and lateral ( ) channels.PR PR

) ,max( PRPRPR

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AGREEMENT BETWEEN GROUND-BASEDAND IN FLIGHT SIMULATION

Landing

Initial stage (2001)

ΔPRflight

ΔP

Rgr

oun

d

ΔPRflight = 8 ΔPRground = 4,5

Final stage (2005)

ΔPRflight = 8 ΔPRground = 6,5

14AGREEMENT BETWEEN GROUND-BASED

AND IN FLIGHT SIMULATION IN DIFFERENT PILOTING TASKS

— in flight

— ground-based

6.5

8.0

9.0 9.0

5.05.5

Δ PR

Landing Refueling Aim-to-aim tracking

2.0

4.0

6.0

8.0

10.0

0

Lev

el o

f ra

tin

g

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Manual control for ESTOL

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PROBLEMS

Low velocity in manual landing

High Thrust Force and angle of attack

Possible loss of visual contact with ground

surface

Unsatisfactorylateral FQ

ReversibleControl

in longitudinal channel

Solution of problems

TV camera for visual contact with ground

surface + display with additional metrics and

Zoom = f(L)

Bank anglefeedback control

Velocityfeedback control

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EFFECT OF FLYING QUALITIES IMPROVEMENT :

а) improvement of pilot rating :

without automation PR = 8,

with developed means PR = 4 – 5

б) improvement of accuracy (variance of longitudinal error) in 15 times

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MAV dynamics and design

Peculiarities of MAV

• Low velocities, mass, inertia, wing loading.

Aircraft MAV

mg/S, n/m2

inertia Iy , kg/m4

200 400 ~ 2

104 105 0,5 ·10-3

• Low Reynolds numbers peculiarities in aerodynamics.

• unusual dynamic response:

– instantaneous change of moments and quick change of forces

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First phase of investigation(april – september 2004)

– Estimation of aerodynamic coefficients (CL , CD , mq , mδ … ).

– Estimation of flight performances and flying qualities.

– Simulation of flight.

– Preliminary FCS design.

M

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Analysis of MAV flight dynamics

s1s

2 ss2 ωsp

2ωspξsp

s2sz

)( sδe

)( sΘ

Phugoid mode Short-period mode

ωph

ωsp

s1

s2

  Aircraft MAV

0,1-0,01 0,8-1,5

1-3 15-20

1-2 10-20

0,01-0,001 0,1-0,5

MAVaircraft

2 ss2 ωph

2ωphξph

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Ways for improvement of MAV flying qualities

Radiocanal

RadiocanalOperator

station Prefilter MAV TVcamera

Use of prefilters

WФ = WФ1 WФ2

WФ1 = T1 s + 1

T1 s

T1 = 0,5c

WФ2 = T2 s + 1

1

T2 = 0,2c

TV-signalControlsignals

RECIEVER Operatorstation

TRANSMITTER– COMPUTER

– AD / DC (converter)

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1. Wind tunnel tests

2. Modification of mathematical model

3. Automation of MAV

4. MAV design

Second phase of investigation(2005)

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WIND TUNNEL TESTS

GOALS

• Influence of low Reynolds numbers, Re

• Influence of propeller

а) Considerable increase of СL max

b) Decrease of L/D ratio

)(vFDL

24Models in the Wind tunnel

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1. Longitudinal channel

Automation of MAV

t, c

q δe

H δe

2. Lateral channel

p δr

ψ δr

r δa

φ δa

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FIRST FLIGHT OF DEVELOPED MAV

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