1Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

Less

ons

Lear

ned

and

Flig

ht R

esul

tsfr

om th

eF-

15 In

telli

gent

Flig

ht C

ontr

ol S

yste

m P

roje

ct

John

Bos

wor

thPr

ojec

t Chi

ef E

ngin

eer

Febr

uary

200

6N

ASA

, Dry

den

Flig

ht R

esea

rch

Cen

ter

2Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

Proj

ect P

artic

ipan

ts

•N

asa

Dry

den

Flig

ht R

esea

rch

Cen

ter

–R

espo

nsib

le te

st o

rgan

izat

ion

for t

he fl

ight

exp

erim

ent

•Fl

ight

, ran

ge a

nd g

roun

d sa

fety

•M

issi

on s

ucce

ss•

Nas

a A

mes

Res

earc

h C

ente

r–

Dev

elop

men

t of t

he c

once

pts

•B

oein

g ST

L Ph

anto

m W

orks

–P

rimar

y fli

ght c

ontro

l sys

tem

sof

twar

e (C

onve

ntio

nal m

ode)

–R

esea

rch

fligh

t con

trol s

yste

m s

oftw

are

(Enh

ance

d m

ode)

•In

stitu

te fo

r Sci

entif

ic R

esea

rch

–N

eura

l Net

wor

k ad

aptiv

e so

ftwar

e•

Aca

dem

ia–

Wes

t Virg

inia

Uni

vers

ity–

Geo

rgia

Tec

h–

Texa

s A

&M

3Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

F-15

IFC

S Pr

ojec

t Goa

ls

•D

emon

stra

te R

evol

utio

nary

Con

trol

App

roac

hes

that

can

Effic

ient

ly O

ptim

ize

Airc

raft

Perf

orm

ance

in b

oth

Nor

mal

and

Fai

lure

Con

ditio

ns

•A

dvan

ce N

eura

l Net

wor

k-B

ased

Flig

ht C

ontr

olTe

chno

logy

for N

ew A

eros

pace

Sys

tem

s D

esig

ns

4Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

4

Mot

ivat

ion

Thes

e ar

e su

rviv

able

acc

iden

ts

IFC

S ha

s po

tent

ial t

ore

duce

the

amou

nt o

fsk

ill a

nd lu

ck re

quire

dfo

r sur

viva

l

5Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

IFC

S A

ppro

ach

•Im

plem

ente

d on

NA

SA F

-15

#837

(SM

TD a

ndA

CTI

VE p

roje

cts)

•U

se E

xist

ing

Rev

ersi

onar

y R

esea

rch

Syst

em

•Li

mite

d Fl

ight

Env

elop

e

•Fa

ilure

s Si

mul

ated

by

Froz

en S

urfa

ce C

omm

and

(Sta

b) o

r Gai

n M

odifi

catio

n on

the

Ang

le o

f Atta

ckto

Can

ard

Feed

back

6Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eerPr

oduc

tion

desig

nP/

Y th

rust

vect

orin

g no

zzle

s

Can

ards

F100

-PW

-229

IPE

engi

nes w

ithID

EEC

s

Qua

d di

gita

l flig

ht c

ontr

olco

mpu

ters

with

res

earc

hpr

oces

sors

and

qua

ddi

gita

l ele

ctro

nic

thro

ttles

AR

TS II

com

pute

r fo

r hi

ghco

mpu

tatio

n re

sear

ch c

ontr

olla

ws

Elec

tron

ic a

irin

let

cont

rolle

rs

•No

mec

hani

cal o

ran

alog

bac

kup

•Dig

ital fl

y-by

-wir

eac

tuat

ors

•Fou

r hy

drau

licsy

stem

s

NA

SA F

-15

#837

Airc

raft

Des

crip

tion

7Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

Flig

ht E

nvel

ope

For G

en 2

M

ach

< 0.

95

8Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

Lim

ited

Aut

horit

y Sy

stem

•A

dapt

atio

n al

gorit

hmim

plem

ente

d in

sep

arat

epr

oces

sor

–C

lass

B s

oftw

are

–A

utoc

oded

dire

ctly

from

Sim

ulin

k bl

ock

diag

ram

–M

any

conf

igur

able

set

tings

•Le

arni

ng ra

tes

•W

eigh

t lim

its•

Thre

shol

ds, e

tc.

•C

ontr

ol la

ws

prog

ram

med

inC

lass

A, q

uad-

redu

ndan

tsy

stem

•Pr

otec

tion

prov

ided

by

float

ing

limite

r on

adap

tatio

nsi

gnal

s

Ada

ptiv

eA

lgor

ithm

Safe

tyLi

mits

Res

earc

h C

ontr

olle

r4

Cha

nnel

680

40

Sing

le C

hann

el 4

00 M

hz

Con

vent

iona

l Con

trol

ler

9Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

Max

per

sist

ence

ctr

,do

wnm

ode

NN

Flo

atin

g Li

mite

r

Upp

er ra

nge

limit

(dow

n m

ode)

Low

er ra

nge

limit

(dow

n m

ode)

Floa

ting

limite

r

Rat

e lim

it dr

ift,

star

t per

sist

ence

coun

ter

Tuna

ble

met

rics

W

indo

w d

elta

D

rift r

ate

Pe

rsis

tenc

e lim

iter

R

ange

lim

its

Win

dow

siz

e

Sigm

a pi

cm

d (p

qr)

Bla

ck –

sig

ma

pi c

md

Gre

en –

floa

ting

limite

r bou

ndar

yO

rang

e –

limite

d co

mm

and

(fl_d

rift_

flag)

Red

– d

own

mod

e co

nditi

on (f

l_dm

ode_

flag

10Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

Flig

ht E

xper

imen

t

•A

sses

s ha

ndlin

g qu

aliti

es o

f Gen

II c

ontr

olle

rw

ithou

t ada

ptat

ion

•A

ctiv

ate

adap

tatio

n an

d as

sess

cha

nges

inha

ndlin

g qu

aliti

es•

Intr

oduc

e si

mul

ated

failu

res

–C

ontr

ol s

urfa

ce lo

cked

(“B

mat

rix fa

ilure

”)–

Ang

le o

f atta

ck to

can

ard

feed

back

gai

n ch

ange

(“A

mat

rix fa

ilure

”)•

Re-

asse

ss h

andl

ing

qual

ities

with

sim

ulat

edfa

ilure

s an

d ad

apta

tion.

•R

epor

t on

“Rea

l Wor

ld”

expe

rienc

e w

ith a

neu

ral

netw

ork

base

d fli

ght c

ontr

ol s

yste

m

11Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

Ada

ptat

ion

Goa

ls

•A

bilit

y to

sup

pres

s in

itial

tran

sien

t due

to fa

ilure

–Tr

ade-

off b

etw

een

high

lear

ning

rate

and

sta

bilit

y of

syst

em•

Abi

lity

to re

-est

ablis

h m

odel

follo

win

gpe

rfor

man

ce•

Abi

lity

to s

uppr

ess

cros

s co

uplin

g be

twee

n ax

es–

No

exis

ting

crite

ria

12Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

Han

dlin

g Q

ualit

ies

Perf

orm

ance

Met

ric

•G

rey

Reg

ion:

–B

ased

on

mod

el-to

-be

-follo

wed

–M

axim

um n

otic

eabl

edy

nam

ics

(LO

ES)

13Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

Proj

ect P

hase

s•

Fund

ed–

Gen

1 In

dire

ct a

dapt

ive

syst

em•

Iden

tify

chan

ges

to “

plan

t”•

Ada

pt c

ontr

ols

base

d on

cha

nges

•LQ

R m

odel

bas

ed c

ontr

olle

r (on

line

Ric

atti

solv

er)

–G

en 2

Dire

ct a

dapt

ive

•Fe

edba

ck e

rror

driv

es a

dapt

atio

n ch

ange

s•

Dyn

amic

inve

rsio

n ba

sed

cont

rolle

r with

exp

licit

mod

el fo

llow

ing

•Fu

ture

Pot

entia

l–

Gen

2+

Diff

eren

t Neu

ral N

etw

ork

appr

oach

es•

Sing

le h

idde

n la

yer,

radi

al b

asis

, etc

–G

en 3

ada

ptiv

e m

ixer

and

ada

ptiv

e cr

itic

14Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

Gen

erat

ion

1

Indi

rect

Ada

ptiv

e Sy

stem

15Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

Indi

rect

Ada

ptiv

e C

ontr

ol A

rchi

tect

ure Pr

etra

ined

N

eura

l N

etw

ork

SCE-

3SC

SI

Sens

ors

Con

trol

Com

man

ds

Pilo

tIn

puts

PTN

ND

eriv

ativ

es

DC

SD

eriv

ativ

esDC

SN

eura

lN

etw

ork

PID

Der

ivat

ive

Estim

atio

n

Der

ivat

ive

Estim

ates

Der

ivat

ive

Erro

rs

+

AR

TS II

Ope

nLo

opLe

arni

ng

Clo

sed

Loop

Lear

ning

Der

ivat

ive

Bia

s

++

16Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

Indi

rect

Ada

ptiv

eEx

perie

nce

and

Less

ons

Lear

ned

•Sy

stem

flow

n in

200

3 –

Ope

n lo

op o

nly

•G

ain

calc

ulat

ion

sens

itive

to id

entif

ied

deriv

ativ

es–

Unc

erta

inty

in e

stim

ated

der

ivat

ive

too

high

•D

iffic

ult t

o es

timat

e de

rivat

ives

from

pilo

t exc

itatio

n–

Nor

mal

ly c

orre

late

d su

rfac

es–

Bet

ter e

stim

atio

n av

aila

ble

with

forc

ed e

xcita

tion

•M

any

deriv

ativ

es re

quire

d fo

r ful

l pla

nt e

stim

atio

n H

owev

er m

ore

are

requ

ired

whe

n La

tDir

coup

les

with

Lon

g•

No

imm

edia

te a

dapt

atio

n w

ith fa

ilure

–R

equi

res

perio

d of

tim

e be

fore

new

pla

nt c

an b

e id

entif

ied

•In

dire

ct a

dapt

ive

mig

ht b

e m

ore

suite

d fo

r cle

aran

ce o

f new

vehi

cles

rath

er th

an fa

ilure

ada

ptat

ion

17Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

Gen

erat

ion

2

Dire

ct A

dapt

ive

Syst

em

18Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

pilo

tin

puts

Sens

ors

Mod

elFo

llow

ing

Con

trol

Allo

catio

n

Res

earc

h C

ontro

ller

-

Dire

ct A

dapt

ive

Neu

ral N

etw

ork

+

Gen

II D

irect

Ada

ptiv

e C

ontr

ol A

rchi

tect

ure

(Ada

ptiv

e)

Feed

back

Erro

r

19Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

Cur

rent

Sta

tus

•G

en 2

–C

urre

ntly

in fl

ight

test

pha

se–

Sim

plifi

ed S

igm

a-Pi

neu

ral n

etw

ork

•N

o hi

gher

ord

er te

rms

•Li

mits

on

Wei

ghts

Qdo

t_c

= Q

_err

*Kpq

*[1

– W

1 –

W2]

+

Q_e

rr_i

nt*K

iq*[

1 - W

1 –

W3]

+ Q

_err

_dot

*Kqd

*[1

– W

1]

20Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

Effe

ct o

f Can

ard

Mul

tiplie

r

A/C

Pla

nt

AoA

Can

ardA

ppar

ent P

lant

Con

trol

Sys

tem

Sym

. Sta

b

Can

.M

ult.

21Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

Sim

ulat

ed C

anar

d Fa

ilure

Stab

Ope

n Lo

op

22Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

Can

ard

Mul

tiplie

r Effe

ctC

lose

d Lo

op F

req.

Res

p.

23Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

Sim

ulat

ed C

anar

d Fa

ilure

Stab

Ope

n Lo

op w

ith A

dapt

atio

n

24Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

Can

ard

Mul

tiplie

r Effe

ctC

lose

d Lo

op w

ith A

dapt

atio

n

25Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

-0.5

can

ard

mul

tiplie

r at f

light

con

ditio

n 1;

with

& w

ithou

t neu

ral n

etw

orks

26Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

010

20

30

40

50

60

70

80

90

100

-1

-0.50

0.51

Roll Axis

NN

Weig

hts

(norm

aliz

ed)

-0.5

canard

: basic

maneuve

ring c

ard

010

20

30

40

50

60

70

80

90

100

-1

-0.50

0.51

Pitch Axis

010

20

30

40

50

60

70

80

90

100

-1

-0.50

0.51

Yaw Axis

Gen

2 N

N W

ts fr

om S

imul

atio

n

27Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

Dire

ct A

dapt

ive

Expe

rienc

e an

d Le

sson

s Le

arne

d

•In

itial

sim

ulat

ion

mod

el h

ad h

igh

band

wid

th–

Maj

ority

of s

yste

m p

erfo

rman

ce a

chie

ved

by th

e dy

nam

ic in

vers

ion

cont

rolle

r–

Dire

ct a

dapt

ive

NN

pla

yed

min

or ro

le•

Dyn

amic

Inve

rsio

n ga

ins

redu

ced

to m

eet A

SE a

ttenu

atio

nre

quire

men

ts–

Muc

h ha

rder

to a

chie

ve d

esire

d pe

rfor

man

ce–

NN

con

trib

utio

n in

crea

sed

•In

itial

per

form

ance

obj

ectiv

e em

phas

ized

tran

sien

t red

uctio

nan

d ac

hiev

ing

mod

el fo

llow

ing

afte

r fai

lure

–Pi

lote

d si

mul

atio

n re

sults

sho

wed

that

redu

cing

cro

ss c

oupl

ing

was

mor

e im

port

ant o

bjec

tive

•Ex

plic

it cr

oss

term

s in

NN

requ

ired

for f

ailu

re c

ases

–R

elyi

ng o

n di

stur

banc

e re

ject

ion

alon

e do

esn’

t wor

k (a

lso

findi

ng o

fG

en 1

)

28Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

Dire

ct A

dapt

ive

Expe

rienc

e an

d Le

sson

s Le

arne

d

•Li

apun

ov p

roof

of b

ound

ed s

tabi

lity

–N

eces

sary

but

not

suf

ficie

nt p

roof

of s

tabi

lity

–M

any

case

s of

lim

it cy

cle

beha

vior

obs

erve

d–

Oth

er a

naly

tic m

etho

ds re

quire

d fo

r ens

urin

g gl

obal

sta

bilit

y•

Dyn

amic

Inve

rsio

n co

ntro

ller c

ontr

ibut

es s

igni

fican

tly to

cro

ssco

uple

d re

spon

se in

pre

senc

e of

sur

face

failu

re (l

ocke

d)–

Red

esig

ned

yaw

loop

usi

ng c

lass

ical

tech

niqu

es•

NN

’s re

quire

car

eful

sel

ectio

n of

inpu

ts–

Pres

ence

of t

rans

ient

err

ors

“nor

mal

” fo

r abr

upt i

nput

s in

non

-ad

aptiv

e sy

stem

s–

Exis

tenc

e of

tran

sien

t err

ors

tend

to d

rive

NN

’s to

“hi

gh g

ain”

tryi

ngto

ach

ieve

impo

ssib

le•

Sign

ifica

nt a

mou

nt o

f “tu

ning

” re

quire

d fo

r to

achi

eve

robu

st fu

llen

velo

pe p

erfo

rman

ce–

Con

trad

icts

cla

im o

f rob

ustn

ess

to u

nfor

esee

n fa

ilure

s–

Pilo

ted

nonl

inea

r sim

ulat

ion

requ

ired

29Jo

hn T

. Bos

wor

th –

Pro

ject

Chi

ef E

ngin

eer

Con

clus

ions

•A

dapt

ive

cont

rols

sta

tus

–C

urre

ntly

col

lect

ing

“rea

l wor

ld”

fligh

t exp

erie

nce

–In

tera

ctio

ns w

ith s

truc

ture

big

gest

cha

lleng

e–

Frui

tful a

rea

for f

utur

e re

sear

ch•

F-15

IFC

S pr

ojec

t is

prov

idin

g va

luab

lere

sear

ch to

pro

mot

e ad

aptiv

e co

ntro

lte

chno

logy

to a

hig

her r

eadi

ness

leve

l