27
Reconfigurable Control Design with Neural Network Augmentation for a Modified F-15 Aircraft AIAA Infotech@Aerospace 2007 Conference and Exhibit 7 - 10 May 2007 Doubletree Hotel Sonoma Wine Country Rohnert Park, California John J. Burken NASA Dryden Flight Research Center

etne C craes a i n r i W a m o n E e c a p s o e Rthgil

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Rec

onfi

gura

ble

Con

trol

Des

ign

wit

h N

eura

l Net

wor

kA

ugm

enta

tion

for

a M

odif

ied

F-1

5 A

ircr

aft

AIA

A Infotech@Aerospace

2007

Co

nfe

ren

ce a

nd

Exh

ibit

7 -

10 M

ay 2

007

Dou

blet

ree

Hot

el S

onom

a W

ine

Cou

ntry

Roh

nert

Par

k, C

alifo

rnia

John

J. B

urke

n

NA

SA D

ryde

n F

light

Res

earc

h C

ente

r

Rec

on

fig

ura

tio

n

Pre

sent

atio

n O

utlin

e

λPu

rpos

e

λB

ackg

roun

d

λD

esig

n M

etho

ds U

sed

for

Pape

r

™B

ackg

roun

d on

Mod

el R

efer

ence

Ada

ptiv

e C

ontr

ol (

MR

AC

)

™B

ackg

roun

d on

Rob

ust S

ervo

mec

hani

sm L

QR

™R

adia

l Bas

is F

unct

ion

Neu

ral N

etw

orks

λC

ontr

ol F

ailu

re S

urvi

vabi

lity

Res

ults

λR

esul

ts /

Tim

e H

isto

ries

λC

oncl

usio

ns

™R

emar

ks

™L

esso

ns L

earn

ed

3

•Mo

tiva

tio

n /

Pro

ble

m S

tate

men

t {

Th

e B

ig P

ictu

re}

•L

and

a d

amag

ed a

irp

lan

e o

r, r

etu

rn t

o a

saf

e ej

ecti

on

sit

e.•O

r co

nti

nu

e w

ith

mis

sio

n

•Gen

eral

Go

als

& O

bje

ctiv

es•F

ligh

t ev

alu

atio

n o

f n

eura

l net

so

ftw

are.

•In

crea

sed

su

rviv

abili

ty in

th

e p

rese

nce

of

failu

res

or

airc

raft

dam

age.

•In

crea

se y

ou

r b

ou

nd

ary

of

a fl

yab

le a

irp

lan

e.•In

crea

se y

ou

r ch

ance

s to

see

an

oth

er d

ay.

Rec

onfi

gura

tion

Flig

ht C

ontr

ol S

yste

ms

Con

trol

Rec

onfig

urat

ion

Con

trol

Rec

onfig

urat

ion

λW

hy A

dapt

ive

Con

trol

.

™H

andl

es u

ncer

tain

ties

and

unp

redi

cted

par

amet

er d

evia

tion

s.

λW

hy R

obus

t C

ontr

ol (

Such

as

Rob

ust

LQ

R s

ervo

des

ign)

™H

andl

es u

nmod

eled

dyn

amic

s.

™H

as g

ood

flig

ht e

xper

ienc

e.

λSo

luti

on t

o A

dapt

ive

& R

obus

t co

ntro

l iss

ues.

™M

erge

ada

ptiv

e au

gmen

tati

on in

to a

rob

ust

base

line

cont

rolle

r.

Gen

eral

Bac

kgro

un

d /

Co

nce

pts

•T

wo

Typ

es o

f A

dapt

ive

cont

rolle

rs1.

Dir

ect

Ada

ptiv

e2.

Indi

rect

Ada

ptiv

e

•T

he D

irec

t A

dapt

ive

Con

trol

ler

Wor

ks o

n th

e E

rror

s.•

Nee

ds a

Ref

eren

ce M

odel

to

Gen

erat

e P

_err

= (

P_c

md-

Pse

nsor

)•

The

Neu

ral N

etw

ork

“Dir

ectl

y” A

dapt

s to

P_e

rr.

•D

oes

not

need

to

know

the

sou

rce

of e

rror

.•

No

Aer

o P

aram

eter

Est

imat

ion

Nee

ded

•N

o ne

ed f

or p

ersi

sten

tly

exci

ting

sig

nals

•T

he I

ndir

ect

Ada

ptiv

e W

orks

on

Iden

tify

ing

the

sour

ce o

f E

rror

.•

Doe

s N

ot N

eed

a R

efer

ence

Mod

el.

•N

eeds

to

Iden

tify

the

Aer

odyn

amic

s th

at h

ave

chan

ged!

(P

ID)

•P

ID is

Tim

e C

onsu

min

g an

d m

ay n

ot b

e co

rrec

t.•

Nee

ds p

ersi

sten

tly

exci

ting

inpu

ts.

Gen

eral

Sta

tem

ents

on

Ada

ptiv

e C

ontr

olle

r

Mod

el R

efer

ence

Ada

ptiv

e C

ontr

ol (

MR

AC

)M

odel

Ref

eren

ce A

dapt

ive

Con

trol

(M

RA

C)

λP

lant

: A

ctua

l Pla

nt p

aram

eter

s (G

) ar

e un

know

n.

λR

efer

ence

Mod

el:

Idea

l res

pons

e (y

m)

to c

md

r (U

se a

Sta

ble

Ref

eren

ce M

odel

).

λA

dapt

atio

n L

aw:

Is u

sed

to a

djus

t co

ntro

ller

(H):

can

be

NN

s.

Ref

eren

ce M

odel

:C

lose

d L

oop

Sys

Plan

t (G

)r

erro

r

Ada

ptiv

e L

aw (

NN

)

Con

trol

ler

(H)

+_

ym

yu

_+

Θ∧

Serv

omec

hani

sm D

esig

n M

etho

dolo

gy

cc

i

cc

cc

c

cc

cc

pm

n

xk

kx

u

pn

DC

BA

ran

k

UD

BB

xx

AC

B

0A

xx

sy

ste

m

MIM

O

a C

on

sid

er

is

co

ntr

oll

er

d

yn

am

ic

Th

e

y)

(rB

xA

x

s

urf

ac

e)

(f

ail

ed

e

dis

turb

an

c

the

w

Fw

D

uC

xY

Ry,

R

u ,R

x re

Ew

wh

eB

uA

xX

+=

+=

! "#$ %&

'

'

! "#$ %& '

+! "#

$ %& ! "#$ %& '

=

!! "#

$$ %&

'+

=

=

++

=

((

(+

+= ••

law

co

ntr

ol

aex

ist

th

ere

a

nd

le

con

tro

lla

b

is sy

stem

T

he

sati

sfie

d

is

con

dit

ion

fo

llo

win

g

the

S

up

po

se

is

syst

em

au

gm

ente

d

loo

p

op

en

Th

e

Not

e :

ℵ L

QR

Ser

vo =

LQ

R P

Iℵ

Jam

med

or

faile

d su

rfac

e is

tre

ated

a

s a

dist

urba

nce

to t

he s

yste

m.

ℑ A

ppro

ach

is s

impl

e to

impl

emen

t.

If th

is s

tate

men

t is

true

ther

eex

ist a

clo

sed-

loop

sys

tem

that

is s

tabl

e.

Ser

vom

ech

anis

m D

esig

n M

eth

od

olo

gy

(co

nt.

)

λR

emar

ks:

λFo

r an

y su

ch c

ontr

ol la

w, a

sym

ptot

ic tr

acki

ng a

nddi

stur

banc

e re

ject

ion

are

achi

eved

; tha

t is,

the

erro

rgo

es to

zer

o.λ

If th

e au

gmen

ted

syst

em is

con

trol

labl

e, th

e co

ntro

lla

w c

an b

e co

nven

ient

ly f

ound

by

appl

ying

the

linea

r qu

adra

tic r

egul

ator

(L

QR

) ap

proa

ch to

the

augm

ente

d sy

stem

Aft

er s

ettin

g up

the

augm

enta

tion

we

now

nee

d to

solv

e fo

r th

e ga

in (

k, k

c)™

Just

use

LQ

R.

™T

his

setu

p al

low

s fo

r a

LQ

R tr

acke

r so

lutio

n.

ccx

kkx

u+

=

Con

trol

Law

e=r!y"0

UD

BB

xx

AC

B

0A

xx

cc

cc

c

! "#$ %& '

+! "#

$ %& ! "#$ %& '

=

!! "#

$$ %&••

is

syst

em

au

gm

ente

d

Th

e

Ser

vom

ech

anis

m D

esig

n M

eth

od

olo

gy

(co

nt.

)

λO

ptim

ize

the

follo

win

g co

st f

unct

ion.

O

ptim

al li

near

-qua

drat

ic-r

egul

ator

(L

QR

) pr

oble

m.

λT

he a

lgeb

raic

Ric

cati

equa

tion

λA

nd th

e op

timal

con

trol

is g

iven

by:

dt

Ru

uQx

xJ

T

)(

'

0

'+

=!

PB

PBR

QPA

PA

'1

'0

!!

++

=

)(

)(

)(

'1

tKx

tPx

BR

tu

=!

=!

Why

Neu

ral N

etw

orks

?W

hy N

eura

l Net

wor

ks?

–Neu

ral N

etw

ork

s ar

e U

niv

ersa

l Ap

pro

xim

ato

rs.

–Min

imiz

es a

H2

no

rm.

–Th

ey p

erm

it a

no

nlin

ear

par

amet

eriz

atio

n o

f u

nce

rtai

nty

.

–Wh

y R

adia

l Bas

is F

un

ctio

ns

(RB

F):

–RB

Fs

will

de-

acti

vate

wh

en s

ign

al is

ou

tsid

e “n

eig

hb

orh

oo

d”.

!! "#

$$ %&'

'

=

()

2)

(

2r

x

ex

Act

ivat

ion

func

tion

λT

he o

utpu

t of

a R

BF

netw

ork

with

K n

euro

ns:

is

the

resp

onse

of

the

kth

hidd

en n

euro

n fo

rin

put v

ecto

r x.

is

the

conn

ectin

g w

eigh

t of

the

outp

ut n

euro

n.

! =

+=

=

K k

kk

bx

wx

NN

xf

1

)(

)(

)(

"

)(xk

!

kw

RB

F N

etw

ork

Out

puts

b x 1 x 2

f j

b x 1 x 2 x 3 x 1x 2

Σ

w0

w1

w2

w3

w4

w0 w1

w2

w3

w4

+ + + + +

f j =

1 ! ! ! !

mea

ns a

ctiv

atio

n fu

nctio

n!

Neu

rons

1 H

idde

n la

yer

with

4 N

euro

ns a

nd 2

Inpu

ts

Fai

lure

sF

ailu

res

Inve

stig

ated

Inve

stig

ated

2 gr

oups

of

failu

res

are

“com

mon

” am

ong

airc

raft

mis

haps

/cra

shes

.

•A

erod

ynam

ic F

ailu

res

or u

ncer

tain

ties

(A M

atri

x pr

oble

ms

/ lo

stae

ro s

urfa

ces,

ben

t win

gs)

•O

r N

ot w

ell k

now

n ae

ro te

rms

due

to m

odel

ling

erro

rs.

•C

ontr

ol F

ailu

res

(B M

atri

x pr

oble

ms

/ jam

med

con

trol

sur

face

s)•

Rig

ht s

tab

jam

med

at 8

. deg

fro

m tr

im

Con

trol

Rec

onfig

urat

ion

Res

ults

Con

trol

Rec

onfig

urat

ion

Res

ults

λT

ime

His

tory

of

Surf

ace

Fai

lure

( B

mat

rix)

λF

ailu

re =

Rig

ht S

tabi

lato

r Ja

mm

ed.

™A

t ti

me

= 1

0 se

cond

s / 8

deg

fro

m t

rim

.

™A

t ti

me

= 3

0 se

cond

s F

ailu

re g

oes

away

(cr

ew f

ixed

the

fai

lure

).

λN

eura

l Net

wor

ks

™N

eura

l Net

wor

ks t

urne

d of

f fo

r th

e fi

rst

run.

™N

eura

l Net

wor

ks t

urne

d on

for

sec

ond

run.

™W

itho

ut D

ead

Zon

es.

Rob

ust M

odel

Ref

eren

ce A

dapt

ive

Con

trol

Des

ign

Pilot InputsF

ailu

re =

Rig

ht S

tab

8. d

eg a

t 10

seco

nds

with

& w

ithou

t NN

Fai

lure

goe

s aw

ay a

t 30

seco

nds

/ Pilo

t Inp

ut is

Rol

l dou

blet

s

Pitchstick

Rollstick

Rudderpedal

Long Axis DataF

ailu

re =

Rig

ht S

tab

8. d

eg a

t 10

seco

nds

with

& w

ithou

t NN

Fai

lure

goe

s aw

ay a

t 30

seco

nds

/ Pilo

t Inp

ut is

Rol

l dou

blet

s

F-15

Lon

gitu

dina

l Par

amet

ers

Lat/Dir Axis DataF

ailu

re =

Rig

ht S

tab

8. d

eg a

t 10

seco

nds

with

& w

ithou

t NN

Fai

lure

goe

s aw

ay a

t 30

seco

nds

/ Pilo

t Inp

ut is

Rol

l dou

blet

s

F-15

Lat

/Dir

Para

met

ers

Fai

lure

= R

ight

Sta

b 8.

deg

at 1

0 se

cond

s w

ith &

with

out N

NF

ailu

re g

oes

away

at 3

0 se

cond

s / P

ilot I

nput

is R

oll d

oubl

ets

Neural Network Signals

Surface Positions F

ailu

re =

Rig

ht S

tab

8. d

eg a

t 10

seco

nds

with

& w

ithou

t NN

Fai

lure

goe

s aw

ay a

t 30

seco

nds

/ Pilo

t Inp

ut is

Rol

l dou

blet

s

Con

trol

Rec

onfig

urat

ion

Res

ults

Con

trol

Rec

onfig

urat

ion

Res

ults

λT

ime

His

tory

of

Surf

ace

Fai

lure

( B

mat

rix)

λF

ailu

re =

Rig

ht S

tabi

lato

r Ja

mm

ed.

™A

t ti

me

= 1

0 se

cond

s / 8

deg

fro

m t

rim

.

™A

t ti

me

= 3

0 se

cond

s F

ailu

re g

oes

away

(cr

ew f

ixed

the

fai

lure

).

λN

eura

l Net

wor

ks

™N

eura

l Net

wor

ks t

urne

d of

f fo

r th

e fi

rst

run.

™N

eura

l Net

wor

ks t

urne

d on

for

sec

ond

run.

™W

ith

Dea

d Z

ones

& 2

0% d

ecre

ase

in le

arni

ng r

ates

.

Pilot InputsF

ailu

re =

Rig

ht S

tab

8. d

eg a

t 10

seco

nds

with

& w

ithou

t NN

Fai

lure

goe

s aw

ay a

t 30

seco

nds

/ Pilo

t Inp

ut is

Rol

l dou

blet

s

NN

with

Dea

d-Z

ones

&Sl

ower

Lea

rnin

g

Pitchstick

Rollstick

Rudderpedal

Long Axis DataF

ailu

re =

Rig

ht S

tab

8. d

eg a

t 10

seco

nds

with

& w

ithou

t NN

Fai

lure

goe

s aw

ay a

t 30

seco

nds

/ Pilo

t Inp

ut is

Rol

l dou

blet

s

NN

with

Dea

d-Z

ones

&Sl

ower

Lea

rnin

g

F-15

Lon

gitu

dina

l Par

amet

ers

Lat/Dir Axis DataF

ailu

re =

Rig

ht S

tab

8. d

eg a

t 10

seco

nds

with

& w

ithou

t NN

Fai

lure

goe

s aw

ay a

t 30

seco

nds

/ Pilo

t Inp

ut is

Rol

l dou

blet

s

NN

with

Dea

d-Z

ones

&Sl

ower

Lea

rnin

g

F-15

Lat

/Dir

Par

amet

ers

Fai

lure

= R

ight

Sta

b 8.

deg

at 1

0 se

cond

s w

ith &

with

out N

NF

ailu

re g

oes

away

at 3

0 se

cond

s / P

ilot I

nput

is R

oll d

oubl

ets

Neural Network Signals

NN

with

Dea

d-Z

ones

&Sl

ower

Lea

rnin

g

Surface Positions F

ailu

re =

Rig

ht S

tab

8. d

eg a

t 10

seco

nds

with

& w

ithou

t NN

Fai

lure

goe

s aw

ay a

t 30

seco

nds

/ Pilo

t Inp

ut is

Rol

l dou

blet

s

NN

with

Dea

d-Z

ones

&Sl

ower

Lea

rnin

g

•C

on

clu

sio

ns

& R

emar

ks

λM

eth

od

pre

sen

ted

:™

Ro

bu

st L

QR

Ser

vom

ech

anis

m d

esig

n w

ith

Mo

del

Ref

eren

ce A

dap

tive

Co

ntr

ol

∧R

efer

ence

Mo

del

was

a “

hea

lth

y”

airc

raft

.™

Use

d R

adia

l Bas

is F

un

ctio

n N

eura

l Net

wo

rks

λR

esu

lts:

™L

QR

Ser

vom

ech

anis

m b

ehav

ed w

ell w

ith

a f

ailu

re.

™U

sin

g t

he

Neu

ral N

etw

ork

s im

pro

ved

th

e tr

acki

ng

co

mp

ared

to

no

t u

sin

g t

he

neu

ral n

etw

ork

s.

λL

esso

n le

arn

ed:

™T

est

the

rem

ova

l of

the

failu

re w

ith

Neu

ral N

etw

ork

s ac

tive

to

en

sure

go

od

per

form

ance

.∧

Th

e cr

ew c

ou

ld f

ix t

he

pro

ble

ms

and

yo

u d

on

’t w

ant

the

adap

tive

sys

tem

to

go

un

stab

le.

Con

trol

Rec

onfi

gura

tion

Con

clus

ions