4 control systems - differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/dydaktyka/basics of...

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Wrocław 2007 Faculty of Mechanical and Power Engineering ©Dr inŜ. JANUSZ LICHOTA CONTROL SYSTEMS differential equations of systems linearization

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Page 1: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Wro

cła

w 2

007

Fa

cu

lty o

f M

ech

an

ica

l a

nd

Po

we

r E

ng

ine

eri

ng

©D

r in

Ŝ.

JA

NU

SZ L

ICH

OT

A

CO

NT

RO

L S

YST

EM

S

dif

fere

nti

al equati

ons

of

syst

em

s

lineari

zati

on

Page 2: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

CO

NT

EN

TS

•T

yp

ica

l in

pu

tsi

gn

als

•P

hy

sica

lsy

stem

s d

iffe

ren

tia

l eq

ua

tio

ns

–m

ech

an

ica

l

–el

ectr

ical

–D

C m

oto

rs

–h

yd

rau

lic

–th

erm

al

–C

on

clu

sio

n

•A

na

lyti

cal

solu

tio

ns

of

dif

fere

nti

al

equ

ati

on

s

•G

ener

ali

zati

on

–tr

an

sfer

fu

nct

ion

•L

inea

ra

pp

rox

ima

tio

n o

fd

iffe

ren

tia

leq

ua

tio

ns

Page 3: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Ob

iek

t

Czu

jnik

Prz

etw

orn

ik

Reg

ula

tor

Sił

ow

nik

Nas

taw

nik

Zad

ajn

ik

PLA

CE O

F A

CT

ION

Pro

cess

-+

PR

OC

ES

S

Contr

olle

r

Sensor

Convert

er

Set-

poin

t

Actu

ato

r

Executive p

art

Page 4: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Ho

wto

investigate

adynam

ic p

ropert

ies o

f a p

rocess

?

Page 5: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

TY

PIC

AL IN

PU

T S

IGN

ALS

Sy

gn

ały

sk

ok

ow

eS

yg

nał

y i

mp

uls

ow

eS

yg

nał

y s

ym

etry

czn

e -

fale

Ser

ie i

mp

uls

ów

Sy

gn

ały

zm

od

ulo

wan

eS

zum

bia

ły

Step responses

-squ

are

ste

p

-slo

pin

g s

tep

-sin

usoid

al

Impulse signals

-squ

are

im

pu

lse

-tria

ngle

im

pu

lse

-sin

uso

ida

l im

pu

lse

Symmetrical signals

-squ

are

wa

ve

(re

cta

ngula

r w

ave

)

-tria

ngle

wa

ve

-ra

mp

wa

ve

Con

tro

l in

pu

ts a

re c

alle

d o

ften

sou

rce

te

rms o

r fo

rcin

g inp

uts

Symmetrical signals

-re

cta

ngu

lar-

ram

p w

ave

-sin

e-s

lope

wa

ve

-sin

e w

ave

Impulse series

-re

cta

ngu

lar

imp

uls

e s

erie

s

-tria

ngle

im

pu

lse

se

rie

s

-sin

e im

pu

lse

se

rie

s

Mo

du

late

d s

igna

ls

-sin

uso

ida

l m

odu

latio

n

-squ

are

modu

lation

White

no

ise

(ra

ndo

m s

igna

l w

ith

fla

t

po

we

r d

en

sity)

Page 6: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Diracdelta function (impulse) δ δδδ(t) a

llow

sto

receiv

eimpuls

response

ofa s

yste

m

Sim

ple

rule

: send

imp

uls

to a

n s

yste

min

put and o

bserv

e

outp

ut

sig

nal

Pro

cess

u(t

)

t

y(t

)

t

Input

Outp

ut

TY

PIC

AL IN

PU

T S

IGN

ALS

Com

monly

use

d input

signals

Imp

uls

e h

ead

ing t

ow

ard

s

infi

nit

y a

tt=

0

Page 7: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

TY

PIC

AL IN

PU

T S

IGN

ALS

Com

monly

use

d input

signals

u(t

)= δ δδδ(t)

t

u(t

)= δ δδδ(t-t0)

tt 0

Rel

atio

nto

Hea

vis

ide

funct

ion

δ δδδ(t)=d1(t)/dt

(th

est

ep i

np

ut

is t

he

inte

gra

l o

f th

e im

pu

lse

inp

ut)

Bia

sed

imp

uls

eIm

pu

lse

ish

eadin

gto

wa

rds

infi

nit

ya

tt=

0

Th

e H

eav

isid

e fu

nct

ion

isn

’tco

nti

nu

ou

s, t

her

efo

reh

asn

’td

eriv

ativ

e. S

uch

fun

ctio

ns

are

fou

nd

in

dis

trib

uti

on

th

eory

.

Page 8: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Th

est

ep i

sli

mit

of

fun

ctio

nh

(t)

Th

e D

irac

im

pu

lse

is l

imit

of

funct

ion

s

TY

PIC

AL IN

PU

T S

IGN

ALS

Com

monly

use

d input

signals

Are

a=

1

Page 9: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Step (Heavisidefunction) 1(t)

allo

ws

to o

bserv

esyste

m

step response.

Sim

ple

rule

too

:send

ste

p c

hang

eto

an

syste

min

put

and

observ

e o

utp

ut

sig

nal

Pro

cess

u(t

)

t

y(t

)

t

Input

Outp

ut

TY

PIC

AL IN

PU

T S

IGN

ALS

Com

monly

use

d input

signals

1

1(t

-t0)=

1 d

la t

>t 0

1(t

-t0)=

0 d

la t≤t

0

Bia

sed

Heavis

ide f

unction

u(t

) 1t 0

Page 10: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Sinusoidal input signalsin(ω ωωωt)

allo

ws t

o o

bserv

e

frequencyresponse

of

a s

yste

m.

Ste

ady-s

tate

response

ofth

esyste

m t

o a

sin

uso

idalin

pu

t.(C

om

ple

x h

arm

on

ic s

igna

l w

ith

sin

uso

ida

l com

ponen

t w

ith

am

plit

ude

, an

gu

lar

fre

quen

cy

and

pha

se

)

Syste

m

u(t

)

t

y(t

)

t

Input

Outp

ut

TY

PIC

AL IN

PU

T S

IGN

ALS

Com

monly

use

d input

signals

u(t

)=sin

(ω ωωωt)

y(t)=A(ω ωωω)sin(ω ωωωt+

ϕ ϕϕϕ(ω ωωω))

ω-

fre

qu

en

cy, ϕ

-p

ha

se

an

gle

, A

-a

mp

litu

de

Page 11: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

TY

PIC

AL IN

PU

T S

IGN

ALS

A s

yste

m c

an b

e inve

stigate

d b

y d

iffe

rent

input

sig

na

ls.

Dif

fere

nt

rea

ctio

ns

on

inp

ut

sig

na

ls i

n c

yber

net

icsy

stem

Page 12: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Do d

iffe

rentsyste

ms h

ave s

om

eth

ing in

com

mon

?

Page 13: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

DIF

FER

EN

TIA

L E

QU

AT

ION

S O

F S

YST

EM

S

Mechanic

al sy

stem

s

Power Dissipated by

Dampers

Damping Components

Elastic Component

Kinematic

relationships

Newton's 2

ndLaw

Conservation Principles for

Linear and Angular Momentum

Rotational Model

Translational

Model

∑=

aF

mJ

=∑

f(t)

x(t)

m

kc

J

k θ

θ

T

B

2

2

dx

dv

ax

dt

dt

==

=&&

2

2

d dtθ

αθ

==&&

F –

forc

e,

m –

mas

s,

a –

acce

lera

toin

,

x –

dis

pla

cem

ent,

T –

torq

ue,

J –

rota

tion

al i

ner

tia,

α-

ang

ula

rac

cele

rati

on,

θ-an

gula

rdis

pla

cem

ent,

k,B

,c –

coef

fici

ents

spri

ng

Fk

x=

dam

pin

gF

cv

=

dis

sipate

dre

lati

veP

Fv

=

spri

ng

MK

θθ

=

dam

pin

gM

=

dis

sip

ate

dre

lati

veP

=

Page 14: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

DIF

FER

EN

TIA

L E

QU

AT

ION

S O

F S

YST

EM

S

Mechanic

al sy

stem

s-bra

ke

Dam

pin

g m

om

ent

J

k θ

θ

T1

B T1M

tłu

mie

nia

Msi

ły

11

sily

MK

θθ

=

11

1T

Σ=

11

1si

lytlu

mie

nia

MM

TJα

−−

+=

11

11

11

KB

TJ

θθ

ωα

−−

+=

2

11

11

11

2

dd

KB

TJ

dtdt

θ

θθ

θ−

−+

=

2

11

11

11

2

dd

TJ

BK

dtdt

θ

θθ

θ=

++

Fin

dm

oti

on

equ

atio

no

fbra

ke

New

ton

’s2nd

law

Usi

ng

fo

rmu

lafo

r d

amp

ing

mo

men

t

Kin

emat

ic r

elat

ion

s

Eq

uati

on

of

mo

tio

n:

torq

ue-

an

gu

lar

dis

pla

cem

ent

2

12

32

dy

dy

ua

aa

yd

td

t=

++

Dat

a :

J 1,K

θ1

, B

, T

1

Init

ial

cond

itio

ns

are

θ1

(0

), ω

1(0

),tw

ice

inte

gra

l al

low

s to

fin

d a

ngula

r

dis

pla

cem

ent.

Kn

ow

ing

rad

ius

we

can

co

mp

ute

lin

ear

dis

pla

cem

ent.

It i

s eq

uat

ion

of

form

Page 15: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

DIF

FER

EN

TIA

L E

QU

AT

ION

S O

F S

YST

EM

S

Mechanic

al sy

stem

s-gear

Fig

. B

elt c

on

ve

yo

r

(prz

ekła

dnia

cię

gno

wa

)

Pa

ralle

l A

xis

He

lica

l G

ea

rs

Cro

ssed

-He

lica

l G

ea

rsW

orm

gea

rB

eve

l gea

rs

Spur

gears

: g

ears

used to

transm

it r

ota

ry m

otion b

etw

een

para

llel shafts. T

he

y a

re

usually

cylin

dri

cal and h

ave

teeth

that are

str

aig

ht and

para

llel to

the s

haft

axis

. T

heir

majo

r advanta

ge is that th

ey

easy to d

esig

n a

nd

manufa

ctu

re.

Helic

al gears

: H

elic

al gears

are

gears

whic

h m

ay b

e

used for

the tra

nsm

issio

n o

f

motion b

etw

een s

hafts w

ith

either

para

llel or

nonpara

llel

axes. T

hese g

ears

are

often u

sed w

hen loads a

re

very

heavy,

when h

igh

speeds a

re c

alle

d f

or,

or

when it is

im

port

ant to

reduce the n

ois

e level of

the g

earing.

Spu

r gea

rs

Worm

gears

used a

re u

sed w

ith

non-inte

rsecting s

hafts w

hic

h a

re

usually

perp

endic

ula

r to

ea

ch o

ther.

The teeth

on a

worm

gear

are

really

more

sim

ilar

to thre

ads than g

ear

teeth

. W

orm

gears

can p

rovid

e a

larg

e r

eduction in s

haft s

peed

com

pare

d to o

ther

types o

f gears

.

Bevel gears

:

Gears

whic

h a

re u

sed to tra

nsm

it

motion b

etw

een

shaft

s w

hose a

xes insect, u

sually

at

90 d

egre

es

although the

y c

an b

e p

roduced for

alm

ost an

y a

ngle

. S

tra

ight bevel

gears

, lik

e s

pur

gears

, becom

e q

uite

nois

y a

t hig

her

shaft

speeds. S

piral

bevel gears

can

be u

sed to r

educe this

gearing n

ois

e.

Ra

ck a

nd

pin

ion

Page 16: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

R=

gea

r ra

diu

s

)=

# o

f g

ear

teet

h

C=

cir

cum

fere

nce

D=

gea

r d

iam

eter

s=

arc

len

gth

θ=

an

gu

lar

dis

pla

cem

ent

ω=

an

gu

lar

vel

oci

ty

α=

an

gu

lar

acce

lera

tio

n

F=

co

nta

ct f

orc

e b

etw

een

gea

rs

T=

to

rqu

e ac

tin

g o

n a

gea

r

P=

po

wer

= T

ω

DIF

FER

EN

TIA

L E

QU

AT

ION

S O

F S

YST

EM

S

Mechanic

al sy

stem

s-

gear

Gea

r m

oti

on

eq

ua

tio

ns

)2

)1

θ2

s 1 s 2

θ1

R2

R1

12

ss

=G

ear

Pri

nci

ple

1:

Gea

rs i

n c

on

tact

turn

thro

ugh

equ

al a

rc l

eng

ths

11

22

RR

θθ

=2

1

12

R R

θ θ=

12

12

dd

RR

dt

dt

θθ

=1

12

2R

ω=

22

12

12

22

dd

RR

dt

dt

θθ

=1

12

2R

α=

22

22

11

11

2 2

RR

C)

RR

C)

π π=

==

12

12

TT

FR

R=

=

R2

R1

T1

FT

2

F

Th

eref

ore

equ

alan

gle

s(r

ad)

Tak

ing

th

e d

eriv

ativ

es–

ang

ula

r v

elo

city

Tak

ing

th

e d

eriv

ativ

es–

ang

ula

r

acce

lera

toin

Sin

ce t

he

nu

mb

er o

f te

eth

is

pro

po

rtio

nal

to t

he

circ

um

fere

nce

of

the

gea

r

Gea

r P

rin

cip

le 2

:G

ears

in

con

tact

ex

ert

equ

al a

nd

opp

osi

te f

orc

es o

n e

ach

oth

er. T

he

equiv

alen

t to

rqu

es o

f th

e co

nta

ct f

orc

e ar

e

ua

y=

This

is

equ

atio

n o

f ty

pe

Page 17: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

DIF

FER

EN

TIA

L E

QU

AT

ION

S O

F S

YST

EM

S

Ele

ctr

onic

al sy

stem

s 1

Systems of real electrical components are modeled as electrical circuit diagrams

Page 18: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

v o(t

)

i 1

R

L

C

+ -

i 2

i 3

v 1cv

2cv

1

cv 3

cv 4

11

1

1Ov

vdv

Cv

dt

Rdt

L

−=

+∫

2

11

12

Od

vL

dv

Ldv

LC

vdt

Rdt

Rdt

++

=

DIF

FER

EN

TIA

L E

QU

AT

ION

S O

F S

YST

EM

S

Ele

ctr

onic

al sy

stem

s 2

Th

en s

ub

stit

ute

in e

ach

of

thes

e in

to t

he

junct

ion

equ

atio

n. C

urr

ent

i 1is

equ

ali 2

+i 3

This

can

be

sim

pli

fied

and

pla

ced

in

to s

tand

ard

fo

rm a

s

eith

er

2

11

23

2

du

dy

dy

ba

aa

yd

td

td

t=

++

This

is

equ

atio

n o

f ty

pe

Det

erm

ine

the

DE

mo

del

of

volt

ag

e v

1v

ersu

s ti

me

t

Kn

ow

ns:

R

, L

, C

, v

o(t

)

Un

kn

ow

ns:

v

1, i 1

, i 2

, i 3

Jun

ctio

n

We

hav

e 4

equ

atio

ns.

Fo

r ju

nct

ion

, re

sist

or,

cap

acit

or

and

co

il. T

o s

olv

e fo

r th

e v

olt

age,

v1

, th

e oth

er

unkn

ow

ns

nee

d t

o b

e el

imin

ated

fro

m t

he

equ

atio

n.

Eli

min

ate

the

curr

ents

, i 1

, i 2

, an

d i

3.S

tart

by s

olv

ing

each

of

the

con

stit

uti

ve

equ

atio

ns

for

the

i te

rms.

Page 19: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

DIF

FER

EN

TIA

L E

QU

AT

ION

S O

F S

YST

EM

S

Ele

ctr

onic

al sy

stem

s 3

Equ

ival

ent

form

s o

f

cond

ense

r d

escr

ipti

on

2

22

12

2(

)d

udu

ut

LC

RC

udt

dt

=+

+

12

()

()

di

ut

LR

it

udt

=+

+

DE

of

circ

uit

Vo

ltag

eu

1d

ecre

ases

on

co

il, re

sist

or

and

cond

ense

r.

2

12

32

dy

dy

ua

aa

yd

tdt

=+

+T

his

is

equ

atio

n o

f ty

pe

Page 20: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

•Act

uat

ors

•Po

wer

ran

ge–

wat

to

sev

eral

han

dre

d k

W

•Sup

ply

fro

mel

ectr

icn

et, d

iese

l

gen

erat

or

or

bat

tery

DIF

FER

EN

TIA

L E

QU

AT

ION

S O

F S

YST

EM

S

DC

Moto

r –

pri

ncip

leof

opera

tion

Page 21: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

DIF

FER

EN

TIA

L E

QU

AT

ION

S O

F S

YST

EM

S

DC

Moto

r –

applicati

on

Page 22: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Rea

din

g h

ead

Har

d d

rive

VC

M

(Vo

ice

Coil

Mo

tor)

DIF

FER

EN

TIA

L E

QU

AT

ION

S O

F S

YST

EM

S

DC

Moto

r –

applicati

on

Page 23: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

DIF

FER

EN

TIA

L E

QU

AT

ION

S O

F S

YST

EM

S

DC

Moto

r –

applicati

on

Pre

-Am

p -

wzm

acn

iacz

wst

ępn

y

Pea

k d

etec

tor

–u

kła

d w

yk

ryw

ania

mak

sym

aln

ych

zm

ian

nap

ięci

a

Tim

ing

gen

erat

or

–ze

gar

tak

tują

cy

Gre

yco

de

–k

od

Gre

y’a

DS

P –

dig

ital

sig

nal

pro

cess

or

DA

C –

prz

etw

orn

ik c

yfr

ow

o-a

nal

og

ow

y

VC

M D

riv

er –

ster

ow

nik

cew

ki

Spin

con

trol

–re

gula

cja

prę

dk

ośc

i

ob

roto

wej

Spin

dle

dri

ver

–st

erow

nik

prę

dko

ści

ob

roto

wej

Page 24: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Wh

enel

ectr

iccu

rren

tpas

ses

thro

ug

ha

coil

ina

mag

net

icfi

eld

, th

em

agn

etic

forc

ep

rod

uce

sa

torq

ue

wh

ich

turn

the

DC

mo

tor.

W u

zwoje

niu

(p

rzez

któ

re p

łyn

ie p

rąd

) p

rzec

inaj

ącym

po

le

mag

net

ycz

ne

ind

uk

uje

się

siła

wytw

arzaj

ąca

mo

men

t si

ły

ob

raca

jący u

zwoje

nie

Ele

ctri

c cu

rren

t

sup

pli

ed e

xte

rnal

ly

thro

ug

h c

om

uta

tor

Mag

net

ic f

orc

e ac

ts p

erpen

dic

ula

r to

both

wir

e an

d m

agn

etic

fie

ld

F=

BIL

F=

(BxI)

L

DIF

FER

EN

TIA

L E

QU

AT

ION

S O

F S

YST

EM

S

DC

Moto

r –

pri

ncip

le o

f opera

tion

Page 25: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

DIF

FER

EN

TIA

L E

QU

AT

ION

S O

F S

YST

EM

S

DC

Moto

rE

lect

ric

Mo

tors

:

Dir

ect

Cu

rren

t (D

C)

mo

tors

are

torq

ue

tran

sdu

cers

that

conv

ert

elec

tric

al

ener

gy

to m

ech

an

ica

l en

ergy

.

Th

e to

rqu

e d

evel

op

ed b

y t

he

mo

tor

shaf

t is

dir

ectl

y

pro

port

ion

al t

o t

he

ma

gn

etic

flu

xin

th

e st

ator

fiel

d

and

th

e cu

rren

t in

th

e m

oto

r ar

mat

ure

.

Th

e st

ato

r's

mag

net

ic f

ield

can

be

gen

erat

ed b

y u

se o

f

per

ma

nen

t m

ag

net

so

r b

y p

assi

ng

cu

rren

t th

rough

coil

ed w

ires

that

are

att

ach

ed t

o t

he

mo

tor

hou

sin

g.

Wh

en w

ire

coil

s ar

e u

sed

to

gen

erat

e th

is m

agn

etic

fiel

d, th

e cu

rren

t p

assi

ng

thro

ug

h t

hes

e co

ils

is c

alle

d

the

fiel

d c

urr

ent.

Th

e a

rma

ture

usu

ally

co

nsi

sts

of

an i

ron

-co

red

roto

r

wo

un

d w

ith

man

y w

ire

coil

s. C

urr

ent

is p

asse

d t

o t

he

coil

on

th

e ro

tor

by u

se o

f g

rap

hit

e b

rush

esw

hic

h

conta

ct a

co

mm

uta

tor.

T

he

curr

ent

pas

sing

th

rou

gh

the

coil

s o

n t

he

roto

r p

rodu

ces

a m

agn

etic

fie

ldw

hic

h

push

es a

gai

nst

th

e m

agn

etic

fie

ldg

ener

ated

by t

he

stato

r. T

he

curr

ent

pas

sed

thro

ug

h t

hes

e ro

tor

coil

s is

call

ed t

he

arm

atu

re c

urr

ent.

Page 26: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

DIF

FER

EN

TIA

L E

QU

AT

ION

S O

F S

YST

EM

S

DC

Moto

r –

pri

ncip

le o

f opera

tion

Asi

mp

leD

Cel

ectr

icm

oto

r.

Wh

en t

he

coil

is

po

wer

ed, a

mag

net

ic f

ield

is

gen

erat

ed

arou

nd

th

e ar

mat

ure

.T

he

left

sid

e o

f th

e ar

mat

ure

is

push

ed

away

fro

m t

he

left

mag

net

and

dra

wn

to

war

d t

he

righ

t,

cau

sing

ro

tati

on

Th

e ar

mat

ure

conti

nues

toro

tate

Wh

en t

he

arm

atu

re b

eco

mes

ho

rizo

nta

lly

alig

ned

,th

e co

mm

uta

tor

rev

erse

s th

e dir

ecti

on

of

curr

ent

thro

ugh

th

e co

il,re

ver

sing

th

e

mag

net

ic f

ield

.T

he

pro

cess

th

en r

epea

ts.

Page 27: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

If t

he s

haft

of

a D

C m

oto

ris

turn

ed

by

an e

xte

rnal fo

rce,th

em

oto

r w

illact

like

a

genera

tor

and p

roduce a

n E

lectr

om

otive f

orc

e(E

MF

).D

uring n

orm

al opera

tion,th

e

spin

nin

gof

the

moto

rpro

duces

avoltage,

know

nas

the c

ounte

r-E

MF

(C

EM

F)

or

back

EM

F,

because it

opposes t

he a

pplie

d v

oltage

on

the

moto

r.T

his

is t

he

sam

e

EM

Fth

at

is p

roduced w

hen t

he

moto

ris

used

as a

genera

tor

(for

exam

ple

when a

n

ele

ctr

ical lo

ad

(resis

tance)

is p

laced a

cro

ss t

he t

erm

inals

of th

em

oto

rand t

he

moto

rshaft

is d

riven w

ith a

n e

xte

rnal to

rque).

There

fore

,th

e v

oltage

dro

pacro

ss

a

moto

rconsis

ts o

f th

e v

oltage

dro

p,

due

toth

isC

EM

F,

and t

he p

ara

sitic

voltage

dro

pre

sultin

g f

rom

the inte

rnal re

sis

tance o

f th

e a

rmatu

re's

win

din

gs.

Rota

ting m

agnetic fie

ldas a

sum

of

magnetic v

ecto

rs f

rom

3 p

hase

coils

DIF

FER

EN

TIA

L E

QU

AT

ION

S O

F S

YST

EM

S

DC

Moto

r –

pri

ncip

le o

f opera

tion

Page 28: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Researc

hers

at

Univ

ers

ity o

f C

alif

orn

ia,

Berk

ele

y,

ha

ve d

evelo

ped r

ota

tional

bearings b

ased u

pon m

ultiw

all

carb

on n

anotu

bes.

By

att

achin

ga

gold

pla

te

(with d

imensio

ns o

ford

er

100nm

) to

the o

ute

r shell

of

asuspended m

ultiw

all

carb

on n

anotu

be

(lik

e n

este

d c

arb

on c

ylin

ders

),th

ey a

re a

ble

to

ele

ctr

osta

tically

rota

te t

he o

ute

r shell

rela

tive

toth

e inner

core

.T

hese

bearings a

re v

ery

robust;

devic

es h

ave b

een o

scill

ate

d t

housands o

f tim

es

with

no

indic

ation o

f w

ear.

These n

anoele

ctr

om

echanic

al syste

ms

(NE

MS

)

are

the n

ext

ste

pin

min

iatu

rization t

hat m

ay f

ind t

heir w

ay into

com

merc

ial

aspects

in t

he f

utu

re.

Nanom

oto

r constr

ucte

d a

tU

CB

erk

ele

y.

The

moto

ris

about500nm

acro

ss: 300

tim

es s

malle

r th

an the d

iam

ete

r of

a

hum

an h

air

DIF

FER

EN

TIA

L E

QU

AT

ION

S O

F S

YST

EM

S

NanoM

oto

r–

pri

ncip

le o

f opera

tion

Page 29: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

DIF

FER

EN

TIA

L E

QU

AT

ION

S O

F S

YST

EM

S

DC

Moto

r –

pri

ncip

le o

f opera

tion

Page 30: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

•Ap

ply

av

olt

age

toar

mat

ure

•Arm

atu

re r

ota

tes

in m

agn

etic

fie

ld

•Sp

eed

co

ntr

ol

by

:

–A

rmat

ure

vo

ltag

e

–F

ield

Str

eng

th

•S

pee

d i

s p

rop

ort

ion

alto

volt

age

•P

ręd

ko

ść o

bro

tow

a ≈

nap

ięci

e

•T

orq

ue

is p

rop

ort

ion

alto

cu

rren

tM

om

ent

siły

≈p

rąd

•Po

wer

=sp

eed

x t

orq

ue

m/s

Nm

=m

/s k

g m

/s2=

kg

m2/s

3

W=

J/s=

kg

(m/s

)2/s

=k

g m

2/s

3

DIF

FER

EN

TIA

L E

QU

AT

ION

S O

F S

YST

EM

S

DC

Moto

r –

pri

ncip

le o

f opera

tion

Sp

eed

contr

ol

thro

ugh

arm

ature

volt

age

and

curr

ent

chan

ge

Page 31: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

To

mo

del

lin

g w

e ca

n a

ssu

me

* A

rmat

ure

iner

tia

J =

0.0

1 k

g m

2/s

2

* T

orq

ue

dis

sip

atio

n c

oef

fici

ent

b =

0.1

Nm

s

* c

on

stan

t K

=K

e=K

t =

0.0

1 N

m/A

* r

esis

tance

R =

1 o

hm

* i

nd

uct

ance

L =

0.5

H

* i

np

ut

vo

ltag

eV

:

* o

utp

ut

ang

le t

het

a:

DIF

FER

EN

TIA

L E

QU

AT

ION

S O

F S

YST

EM

S

DC

Moto

r –

equati

on o

f m

oti

on θ& et

Ke

iK

T

==

Page 32: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

DIF

FER

EN

TIA

L E

QU

AT

ION

S O

F S

YST

EM

S

Ele

ktr

om

echanic

al sy

stem

u

i adc

Ra

La

J

aa

aa

b

di

uR

iL

ed

t=

++

ω ωωω

Mec

han

ical

sub

syst

em

moto

rT

JB

ωω

=+

&

BIn

pu

t: v

olt

age

u

Ou

tput:

Ang

ula

r v

elo

city

ω

Ele

ctri

cal

Sub

syst

em (

loo

p m

etho

d):

e b–

bac

k-e

mf

vo

ltag

e (E

MF

–el

ectr

om

agn

etic

fo

rce)

Page 33: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

ui a

dc

Ra

La

ω ωωω

To

rqu

e-C

urr

ent

:

Vo

ltag

e-S

pee

d:

moto

rt

aT

Ki

=

Co

mb

ing p

rev

ious

equat

ions

resu

lts

in t

he

foll

ow

ing

mat

hem

atic

alm

od

el

B

Po

wer

tra

nsf

orm

atio

n

bb

eK

ω=

-0

aa

aa

b

ta

di

LR

iK

ud

t

JB

Ki

ω

ωω

+

+=

+

=

&

wh

ere

Kt:

torq

ue

const

ant,

Kb:

vel

oci

ty c

on

stan

t.F

or

an i

dea

l m

oto

r

tb

KK

=

DIF

FER

EN

TIA

L E

QU

AT

ION

S O

F S

YST

EM

S

Ele

ctr

om

echanic

alsy

stem

2

12

32

dy

dy

ua

aa

yd

tdt

=+

+

Tim

e d

eriv

atio

n, so

lve

for

i aan

dsu

bst

itute

to

firs

teq

uat

ion

i a, di a/

dt

()

()

...

aa

aa

tb

tL

JJR

BL

BR

KK

Ku

ωω

ω+

++

+=

This

is

equ

atio

n o

f a

typ

e

An

oth

erre

lati

on

bet

wee

nan

gula

r v

elo

city

ωan

d v

olt

age

u

Page 34: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

DIF

FER

EN

TIA

L E

QU

AT

ION

S O

F S

YST

EM

S

DC

Moto

r

Ad

just

th

e v

olt

age

and

cu

rren

t (i

f)

app

lied

to

th

e fi

eld

win

din

g,

or

Ad

just

th

e v

olt

age

and

cu

rren

t ( i A

)

to t

he

arm

atu

re

RA

LA

M,

ωM

v b

KE,K

T

i A

-

i f

J, c

T

v in

M,

ωM

v b

KE,K

T

-

i A

J, c

T

Lf

Rf

v in

i f

Armature Controlled DC Motor Field Controlled DC Motor

Ad

va

nta

ges

:

A

dv

an

tag

es:

--go

od

to

rque

at h

igh s

pee

ds

--ener

gy e

ffic

ient

--sm

all

and

inexp

ensi

ve

contr

oll

er

Dis

ad

va

nta

ges

:

Dis

ad

va

nta

ges

:

--la

rger

and

mo

re e

xp

ensi

ve

co

ntr

oll

er

--to

rqu

e d

ecre

ases

at

hig

h s

peed

s

--hig

her

ener

gy l

oss

es

-

-var

iab

le l

oad

aff

ects

sp

eed

--vari

able

lo

ad a

ffec

ts s

pee

d

Mo

del

:

Mo

del

:

--li

near

mo

del

--no

nli

nea

r m

od

el

Ma

them

ati

cal

Mo

del

s:

Ele

ctri

cal

Mo

del

Ele

ctri

cal

Mo

del

Mec

hanic

al M

od

elM

ech

anic

al M

od

el

0A

inA

AA

b

di

vi

RL

vd

t−

−−

=0

f

inf

ff

di

vi

RL

dt

−−

=

bE

vK

ω=

0A

AA

AA

b

di

vi

RL

vd

t−

−−

=

bE

fv

Ki

ω=

d

dT

cT

Jd

tωω

−−

=d

dT

cT

Jd

tωω

−−

=

TA

TK

i=

Tf

AT

Ki

i=

vin

= c

ontr

ol

vo

ltage

v

b=

mo

tor

bac

k e

mf

i A=

arm

atu

re c

urr

ent

i f

= f

ield

curr

ent

T =

mo

tor

torq

ue

Td

= d

istu

rban

ce t

orq

ue

on s

haft

J=

mo

tor

iner

tia

c

= m

oto

r d

am

pin

g c

onst

ant

ω=

sp

eed

of

mo

tor

R

A, R

f=

arm

ature

and

fie

ld r

esis

tan

ce

LA

= A

rmat

ure

ind

uct

ance

L

f=

fie

ld i

nd

uct

ance

KE

= K

T:

Mo

tor

const

ants

(usu

ally

fo

und

in s

pec

ific

atio

ns)

.

Page 35: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

DIF

FER

EN

TIA

L E

QU

AT

ION

S O

F S

YST

EM

S

DC

Moto

r –

equati

on o

f m

oti

on

Ste

pp

erm

oto

r

Clo

sely

rel

ated

in

des

ign

toth

ree-

ph

ase

AC

syn

chro

nou

s m

oto

rs a

re s

tep

per

mo

tors

,w

her

e an

inte

rnal

roto

r

conta

inin

g p

erm

anen

t m

agn

ets

or

ala

rge

iro

n c

ore

wit

h s

alie

nt

po

les

is c

ontr

oll

edb

y a

set

of

exte

rnal

mag

net

s th

at a

re

swit

ched

ele

ctro

nic

ally

. A

step

per

mo

tor

may

als

ob

eth

oug

ht

of

as a

cro

ss b

etw

een

a D

Cel

ectr

icm

oto

ran

da

sole

noid

. A

sea

ch c

oil

is

ener

giz

ed i

n t

urn

,th

ero

tor

alig

ns

itse

lf w

ith

th

e m

agn

etic

fie

ld p

rodu

ced

by

the

ener

giz

ed

fiel

d w

indin

g.U

nli

ke

asy

nch

ronou

sm

oto

r,in

its

app

lica

tion

,th

em

oto

rm

ayn

ot

rota

te c

onti

nu

ou

sly;

inst

ead

,it

"ste

ps"

fro

mo

ne

po

siti

on

toth

e n

ext

asfi

eld

win

din

gs

are

ener

giz

ed a

nd

de-

ener

giz

ed i

n s

equ

ence

.D

epen

din

gon

the

seq

uen

ce,th

ero

tor

may

tu

rn f

orw

ard

s o

r bac

kw

ard

s.

Co

ntr

ol

isd

iscr

ete

inti

me

Page 36: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

DIF

FER

EN

TIA

L E

QU

AT

ION

S O

F S

YST

EM

S

Hydra

ulic

syst

em

Mix

ing

of

two

flu

id w

ith

dif

fere

nt

con

cen

trat

ion

C –

con

centr

atio

n,

m –

mas

s st

ream

V –

volu

me

stre

am

t -

tim

e

m V

dC dt

CC

a

aaw

e.

+=

DE

23

dy

ua

ay

dt

=+

Th

is i

s eq

uat

ion

of

typ

e

Page 37: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

DIF

FER

EN

TIA

L E

QU

AT

ION

S O

F S

YST

EM

S

Therm

alsy

stem

V1

V2

V3

V=

abc

Mix

ing t

wo

flu

ids w

ith

diffe

ren

t te

mpe

ratu

res

ρθ

ρθ

ρθ

ρθ

33

3

11

11

22

22

33

33

cV

d dt

cV

cV

cV

pp

pp

=+

−.

..

θθ

θθ

θθ

θθ

θ

110

1

220

21

330

3

=+

=+

=+

∆ ∆ ∆

01

11

12

22

23

33

3=

+−

ρθ

ρθ

ρθ

cV

cV

cV

pp

p

..

.

ρθ

ρθ

ρθ

ρθ

33

3

33

33

11

11

22

22

cV

d

dt

cV

cV

cV

pp

pp

∆∆

∆∆

+=

+.

..

[]

∆∆

∆θ

θθ

31

12

2

1

1(

)(

)(

)s

Ts

ks

ks

=+

+

TV V

kc

V

cV

kc

V

cV

p p

p p

==

=.

. .

. .

30

1

11

10

33

30

1

22

20

33

30

ρ ρ

ρ ρ

En

erg

y c

on

serv

atio

n

Pro

cess

set-

poin

t

Sta

tic

char

acte

rist

ics

in s

tead

y s

tate

Dyn

amic

ch

arac

teri

stic

s

Lap

lace

tra

nsf

orm

2

12

32

dy

dy

ua

aa

yd

tdt

=+

+T

his

is

equ

atio

n o

f ty

pe

Page 38: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Co

ncl

usi

on

Page 39: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

CO

NC

LU

SIO

N

Man

yp

roce

sses

can

be

des

crib

edb

y l

inea

r,

tim

e-in

var

ian

teq

uat

ion

s

22

21

00

12

22

...

...

du

du

dy

dy

aa

au

ay

aa

dt

dt

dt

dt

++

+=

++

+

Page 40: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

“Mat

hem

atic

s co

mp

ares

dif

fere

nt

ph

eno

men

on

s an

d

dis

cov

ers

secr

etan

alo

gie

sb

etw

een

them

Jean Baptiste Joseph Fourier (1768 -1830)

CO

NC

LU

SIO

N

Page 41: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Ho

wto

solv

ediffe

rentia

l eq

uatio

ns?

Page 42: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Analy

tical so

luti

ons

of

dif

fere

nti

al

equati

ons

Classification of Ordinary Differential Equations:

The

rea

son

to

sta

rt w

ith

the

cla

ssific

atio

n o

f diffe

ren

tia

l e

qua

tio

ns is tha

t th

ere

are

diffe

ren

t m

eth

od

s u

sed

to

so

lve

diffe

ren

t ty

pe

s o

f d

iffe

ren

tial e

qua

tion

s.

Som

etim

es y

ou

need

to

know

wh

ich

equa

tio

n t

ype

yo

u h

ave

in

ord

er

to p

ick

an

app

rop

ria

te o

r be

st so

lutio

n m

eth

od

.

To

de

term

ine

the

cla

ssific

ation

of

diffe

ren

tial equ

ation

s,

yo

u s

hou

ld s

tart

by p

utt

ing a

DE

in

to its

sta

nda

rd fo

rm.

Standard Form:

a)

Iden

tify

the

depen

den

t and

ind

epen

den

t va

riab

les.

b)

Pla

ce

all

the

depe

nden

t va

riab

le te

rms o

n the

left

ha

nd

sid

e o

f th

e e

qua

tion

.

c)

Mo

ve

all

oth

er

term

s (

co

nsta

nts

and

in

d.

var.

te

rms)

to t

he

rig

ht

sid

e o

f th

e e

qua

tion

.

d)

Arr

an

ge

all

the

de

riva

tive

s b

y o

rde

r. H

ighe

st

de

riva

tive

goe

sto

the left

.

e)

No

rmaliz

e t

he

coeff

icie

nt

of

the

lo

we

st o

rde

r depe

nden

t va

riab

le t

erm

.

f)

Sim

plif

y t

he

equa

tion

, if p

ossib

le

g)

Asse

mb

le t

he

con

ditio

ns.

The

sta

nda

rd f

orm

of

the

equa

tion

sho

uld

look s

om

eth

ing lik

e th

is.

Som

etim

es e

qua

tion

s,

pa

rtic

ula

rly n

on

linea

r equ

ation

s a

nd

se

ts o

f lin

ked

equa

tion

s, m

ay u

se

a s

ligh

tly d

iffe

ren

t

sta

nda

rd d

iffe

ren

tia

l e

qua

tion

fo

rm.

F

or

the

se

equa

tio

ns,

the

coeff

icie

nt

of

the

hig

he

st

ord

er

de

riva

tive

is n

orm

aliz

ed

to 1

in

ste

ad

of

the

lo

we

st

ord

er

dep

ende

nt

term

.

1

12

1...

()

w

ith

condit

ions

))

))

dx

dx

aa

xf

t)

dt

dt

−+

++

=

1

11

...

0

w

ith

c

on

dit

ions

))

))

)

dx

dx

aa

x)

dt

dt

−+

++

=

Page 43: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Types of features to classify:

Dependent variable:

The

de

pende

nt

va

riab

le(s

) re

pre

se

nts

the

ou

tpu

t va

riab

le(s

) of

the

mod

el.

The

y a

re the

va

ria

ble

s in

the

nu

me

rato

r of

the

de

riva

tive

s in

the

DE

. If

the

mo

de

l con

sis

ts o

f se

ve

ral lin

ked

equa

tion

s,

then

the

re

ma

y b

e m

ultip

le d

epende

nt

va

ria

ble

s.

Depe

nden

t va

riab

le(s

):

x, y,

an

d z

Indepen

den

t va

riab

le(s

):

t

Independent variable

: T

he

va

riab

le in

the

den

om

ina

tor

of

the

diffe

ren

tia

l e

qua

tion

is t

he

ind

epend

en

t va

riab

le.

Yo

u t

yp

ically

pic

k its

ran

ge

when

solv

ing t

he

equ

ation

. O

rdin

ary

diffe

ren

tia

l e

qua

tion

s h

ave

a s

ingle

inde

pende

nt

va

ria

ble

. P

art

ial d

iffe

ren

tia

l e

qua

tio

ns h

ave

seve

ral in

dep

enden

t va

riab

les.

OD

EP

DE

55

22

dx

xy

td

t+

−=

+

53

0d

yt

yx

zd

t+

−+

=

53

dz

zx

dt−

+=

2

25

52

dx

dx

xx

tdt

dt

+−

=2

22

22

5x

xy

xt

∂Ω

∂Ω

∂Ω

∂Ω+

+=

−∂

∂∂

∂∂

Analy

tical so

luti

ons

of

dif

fere

nti

al

equati

ons

Page 44: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Analy

tical so

luti

ons

of

dif

fere

nti

al

equati

ons

Linear or Nonlinear:

An

equa

tion

is lin

ea

r if a

ll de

pend

en

t va

riab

le te

rms a

re r

ais

ed

to

the p

ow

er

of

1 a

nd

are

no

t in

clu

ded

in

tra

nscend

en

tal fu

nction

s (cos

, exp

, ln

, sqrt

, e

tc.)

Lin

ea

rN

on

linea

r

Homogeneous or Nonhomogeneous

: A

n e

qu

ation

is h

om

ogeneou

s if

the

rig

ht ha

nd

sid

e (

the

drive

te

rm)

of

the

sta

nda

rd f

orm

is e

qu

al to

ze

ro,

f(t)

= 0

.

An

y e

qua

tion

with

a n

on

ze

ro d

rive

te

rm is n

onho

mo

geneou

s.

Ho

mo

ge

neou

sN

on

hom

ogeneo

us

2

25

52

dx

dx

xt

dt

dt

+−

=

2

25

52

dx

dx

xx

td

td

t+

−=

2

25(

1)5

2d

xd

xt

xt

dt

dt

++

−=

2

25

5si

n(2

)2

dx

dx

xt

dt

dt

+−

=

2

2

1(

)2

52

sin

5

dx

xt

dt

t+

=+

3

3

18

02

dx

dx

dt

dt

x+

−=

2

25

50

dx

dx

xd

td

t+

−=

2

25

52

dx

dx

xx

td

td

t+

−=

Page 45: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Constant or Variable Coefficient:

An

equa

tion

wh

ich

ha

s in

depen

den

t va

riab

les w

hic

h c

ann

ot be

sepa

rate

d f

rom

the

de

pende

nt

va

riab

le w

hen

the

equa

tion

is p

laced

in

sta

nd

ard

fo

rm is a

va

riab

le c

oeff

icie

nt

equ

ation

. M

an

y v

aria

ble

coe

ffic

ien

t e

qua

tion

s r

equire

so

lution

s w

hic

h, if s

olv

ab

le,

requ

ire

infin

ite

se

rie

s s

olu

tion

s.

Co

nsta

nt

co

eff

icie

nt :

Va

riab

le c

oeff

icie

nt:

Analytical or Tabular Drive term: T

he

drive

te

rm o

n the

rig

ht

hand s

ide

of

the

equa

tion

ma

y s

om

etim

es b

e d

escrib

ed

usin

g e

xpe

rim

en

tal o

r ta

bula

r d

ata. I

f th

e d

rive

te

rm c

an

be

com

ple

tely

exp

resse

d a

s a

n e

qu

ation

in

te

rms o

f th

e

inde

pend

en

t va

riab

le it is

ca

lled

ana

lytica

l.

An

aly

tica

l D

rive

Te

rmT

ab

ula

r D

rive

Te

rm

wh

ere

t

1

10

1

5

25

f(t)

0

0

1

3

g(t

)

10

5

3

2

2

25

52

dx

dx

xx

td

td

t+

−=

2

25(

1)5

2d

xd

xt

xt

dt

dt

++

−=

2

25

52

5co

s(3

)d

xd

xx

xt

td

td

t+

−=

+2

25

52

()

5(

)d

xd

xx

xf

tg

td

td

t+

−=

+

Analy

tical so

luti

ons

of

dif

fere

nti

al

equati

ons

Page 46: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Analy

tical so

luti

ons

of

dif

fere

nti

al

equati

ons

Condition Type: W

hile

in

itia

l cond

itio

ns a

re t

he

mo

st

com

mo

n,

cond

itio

ns m

ay a

lso

be

of

bo

unda

ry a

nd

m

ixed

typ

e.

Initia

l cond

itio

ns o

ccu

r if a

ll co

nd

itio

ns a

re s

pecifie

d a

t th

e s

am

e v

alu

e o

f th

e indepe

nden

t va

riab

le.

Bou

nda

ry

con

ditio

ns e

xis

t if t

he

con

ditio

ns a

re g

iven

at va

lue

s o

f th

e indep

enden

t va

riab

le w

hic

h b

racke

t th

e r

egio

n o

f in

tere

st.

Initia

l C

ond

itio

ns

Bo

un

da

ry C

ond

itio

ns:

with

x(1

) =

20

, (1

)= -

2,

an

d (

1)=

0

w

ith

x(0

) =

20

and

x(5

)= -

2

x& x&&

Page 47: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Methods of Finding Analytical Solutions to Differential Equations:

1)

Separa

tion o

f V

ariable

s M

eth

od

2)

Undete

rmin

ed C

oeff

icie

nt

Meth

od

3)

Variatio

n o

f P

ara

mete

rs M

eth

od

4)

Opera

tor

Me

thod f

or

Hom

ogene

ous E

qu

ations

Analy

tical so

luti

ons

of

dif

fere

nti

al

equati

ons

Page 48: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Separation of Variables Method:

In t

he

se

pa

ratio

n o

f va

riab

le m

eth

od

you

try

to

iso

late

the

depen

den

t an

d indep

enden

t va

riab

les o

n o

ppo

site

sid

es

of

the

equa

tion

, th

en

inte

gra

te e

ach

sid

e indepe

nden

tly.

Th

is is o

ne m

eth

od

tha

t m

ay o

ften w

ork

fo

r non

linea

r,

ho

mo

ge

neou

s 1

sto

rder

pro

ble

ms.

Exa

mp

le:

Solution

2

02

0

wit

h

(0)

dx

xx

xd

t+

==

Analy

tical so

luti

ons

of

dif

fere

nti

al

equati

ons

22

dx

xd

t=

212

dx

dt

x=

00

212

xt

xt

dx

dt

x=

−∫

∫ ] 0

0

12

xt t

x

tx

=−

()

0

0

11

2t

tx

x

−−

=−

()

0

0

11

2t

tx

x=

+−

()

0

0

1

12

x

tt

x

=+

− ()

0

00

12

xx

xt

t=

+−

Page 49: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Analy

tical so

luti

ons

of

dif

fere

nti

al

equati

ons

Undetermined Coefficient Method:

Use

the

und

ete

rmin

ed

coe

ffic

ien

t m

eth

od

to

so

lve

lin

ea

r, o

rdin

ary

, n

on

hom

ogeneo

us e

qu

ation

s w

ith

con

sta

nt

co

eff

icie

nts

.

The

so

lutio

n is fou

nd

by d

ete

rmin

ing t

wo

pa

rts t

o t

he

so

lution

:

The

co

mp

lem

en

tary

so

lution

, x

c,

is s

imp

ly t

he

ho

mo

ge

neou

s s

olu

tion o

bta

ined

wh

en

th

e d

rive

fun

ction

f(t

) is

se

t e

qual to

ze

ro.

The

pa

rtic

ula

r so

lution

, x

p,

accou

nts

fo

r th

e e

ffe

ct

of

the

drive

te

rm.

The

pa

rtic

ula

r so

lution

is

assu

med

to

ha

ve

a fo

rm s

imila

r to

the

drive

fun

ction

bu

t w

ith

a n

um

be

r of

un

kno

wn

coeff

icie

nts

. T

he

assu

med

so

lution

and

its

de

riva

tive

s a

re s

ub

stitu

ted

ba

ck in

to the

nonh

om

ogeneou

s e

qua

tion

and

the

coeff

icie

nts

are

then

de

term

ined

.

1

11

...

()

w

ith

c

on

dit

ion

s)

)

))

)

dx

dx

aa

xf

t)

dt

dt

−+

++

=

cp

xx

x=

+

Page 50: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Example:

Solution

:

The

complementary solution

ha

s a

lread

y b

een

found

fro

m the

solu

tion

of

the

hom

ogene

ous e

qua

tion

in

the

pre

vio

us

exa

mp

le.

Th

e p

arti

cula

r so

luti

on

may b

e fo

un

d b

y a

ssu

min

g t

hat

th

e so

luti

on

tak

es o

n t

he

form

then

its

der

ivat

ive

is

Su

bst

itu

tin

g t

hes

e b

ack

in

to t

he

DE

giv

es

Ali

gn

ing t

he

coef

fici

ents

giv

e:

ther

efo

re t

he

par

ticu

lar

solu

tio

n i

s

and

th

e gen

eral

so

luti

on

is

Fo

r th

e in

itia

l co

nd

itio

n o

f ,

C

1m

ay b

e fo

un

d a

s

ther

efo

re

the

gen

eral

so

luti

on

is

22

35

w

ith

(0

)0

dx

xt

xx

dt+

=+

=

20

d

xx

dt+

=2

1

t

cxC

e−

=

2

12

3

px

At

At

A=

++

12

2

px

At

A=

+&

22

35

pp

xx

t+

=+

&(

)(

)2

2

12

12

32

2

35

A

tA

At

At

At

++

++

=+

()

()

22

11

22

32

22

2

30

5

At

AA

tA

At

t+

++

+=

++

12

3

A=

12

22

0

AA

+=

23

25

A

A+

=1

1.5

A=

21

AA

=−

23

5

2AA

−=

= -

1.5

5(

1.5

) =

=

3.2

52

−−

21.5

1.5

3.2

5

px

tt

=−

+

cp

xx

x=

+2

2

11

.51

.53

.25

t

Ce

tt

−=

+−

+

0(0

)x

x=

2(0

)2

01

(0)

1.5

(0)

1.5

(0)

3.2

5

xx

Ce

−=

=+

−+

01

3.2

5

xC

=+

10

3.2

5

Cx

=−

22

0(

3.2

5)

1.5

1.5

3.2

5

tx

xe

tt

−=

−+

−+

Analy

tical so

luti

ons

of

dif

fere

nti

al

equati

ons

Page 51: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Analy

tical so

luti

ons

of

dif

fere

nti

al

equati

ons

Operator Method:

Use

the

ope

rato

r m

eth

od

to

so

lve

lin

ea

r, o

rdin

ary

, h

om

oge

neou

s e

qua

tion

s w

ith

co

nsta

nt

coe

ffic

ien

ts.

Th

is m

eth

od

is im

ple

men

ted

by r

ep

lacin

g e

ach

ith

de

riva

tive

of

the

de

pende

nt

va

riab

le w

ith

D i .

T

he

equa

tio

n is the

n

so

lved

to

fin

d r

oo

ts (

va

lue

s o

f D

) w

hic

h s

atisfy

th

e "

ch

ara

cte

ristic e

qua

tio

n".

The

cha

racte

ristic e

qua

tio

n is a

ge

ne

ral po

lyno

mia

l w

hic

h s

hou

ldha

ve

Nro

ots

, r 1

, r 2

, .

. . r N

. R

oo

ts m

ay b

e r

ea

l,

multip

le, o

r com

ple

x.

The

fo

rm o

f th

e s

olu

tion

de

pend

s u

pon

the

typ

e o

f ro

ots

pre

sen

t.

If allroots arereal

and

unique

If all roots are real

bu

t not unique

, th

en

the

multip

le r

oo

ts r

equ

ire

a m

ultip

le p

ow

er

of t

be

use

d o

n s

ele

cte

d t

erm

s

If some roots are complex

, th

en

ea

ch

com

ple

x p

air s

olu

tion

ma

y b

e w

ritt

en

in

a n

um

be

r of

com

mon

fo

rms.

1

11

...

0

wit

h

co

nd

itio

ns

))

))

)

dx

dx

aa

x)

dt

dt

−+

++

=

1

1..

.0

))

)D

aD

a−

++

+=

12

12

...

)rt

rt

rt

)x

Ce

Ce

Ce

=+

++

12

22

12

2..

.)r

tr

tr

tr

t

)x

Ce

Cte

Ct

eC

e=

++

++

()

12

12

12

2

1 1

()

()

12

12

12

22

12

2

...

()

...

=

cos

sin

...

=

(si

n)

...

) )

)

)

rt

rir

tr

irt

)

rt

rt

irt

irt

)

rt

rt

)

rt

rt

)

xC

eC

eC

e

eC

eC

eC

e

eA

rt

Ar

tC

e

eB

rt

BC

e

+−

+−

=+

++

=+

++

++

+

++

+

Page 52: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Example:

Fin

d the

so

lution

of

the D

E u

sin

g t

he

Op

era

tor

me

thod

:

Solution:

Le

t t

his

equa

tion

be

rep

resen

ted

usin

g t

he

Dop

era

tor

as

so

the

cha

racte

ristic e

qu

ation

is

Th

is e

qua

tion

ha

s a

n o

rde

r o

f m

agnitude

of

1 (t

he

refo

re N

= 1

and

the

re is o

ne

ro

ot)

The

roo

t is

Sin

ce

th

ere

is o

ne

rea

l ro

ot,

th

e s

olu

tion

fits the

fo

rm o

f

At

the

in

itia

l cond

itio

n

so

app

lyin

g t

he

ge

ne

ral so

lutio

n w

ith

th

e in

itia

l co

nd

itio

n

giv

es t

he

so

lution

as

02

0

wit

h

(0)

dx

xx

xd

t+

==

20

D

xx

+=

()

20

xD

+=

20

D+

=

12

r

=−

12

11

rt

tx

Ce

Ce

−=

=

0(0

)x

x=

02

()

01

1(0

)t

xx

Ce

C−

==

=

2

0(

)t

xt

xe

−=

Analy

tical so

luti

ons

of

dif

fere

nti

al

equati

ons

Page 53: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Gen

era

liza

tio

n–

tra

nsf

er f

un

cti

on

an

d b

asi

c co

mp

on

en

ts

Page 54: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

GEN

ER

ALIZ

AT

ION

Tra

nsf

er f

un

ctio

nit

isra

tio

of

two

com

ple

x p

oly

no

mia

ls

Gs

Ys

Xs

kk

sk

sk

s

Ts

Ts

Ts

nm

n

n

mmm

()

()

()

...

...

,=

=+

++

++

++

+≤

01

2

2

122

21

In m

ath

em

atic

s,th

e fu

nd

amen

tal

theo

rem

of

alg

ebra

stat

es t

hat

ev

ery n

on

-zer

o s

ing

le-v

aria

ble

po

lyn

om

ial,

wit

h c

om

ple

x c

oef

fici

ents

,h

as e

xac

tly

asm

any c

om

ple

x r

oo

tsas

its

deg

ree,

if r

epea

ted

roo

ts a

re c

ou

nte

d u

pto

thei

r m

ult

ipli

city

.E

qu

ival

entl

y,

the

mat

hem

atic

al f

ield

of

com

ple

x n

um

ber

s

is c

lose

d u

nd

er a

lgeb

raic

op

erat

ion

s.In

oth

er w

ord

s, f

or

ever

y c

om

ple

x p

oly

no

mia

lp

of

deg

ree

n >

0

the

equ

atio

np

(z)

= 0

has

ex

actl

yn

com

ple

x s

olu

tio

ns,

cou

nti

ng

mu

ltip

lici

ties

. S

uch

po

lyn

om

ials

can

hav

e fo

rm

()

()

()

()

Ys

Xs

kT

sT

sT

s

sT

sT

sT

s

iiq

iib

idid

idid

j

iri

r

ipip

ipi

p

()

()=

±±

±

±±

±

==

=

==

∏∏

∏∏

11

22

1

1

22

1

12

1

12

1

ξ ξ

Usi

ng

Lap

lace

tra

nsf

orm

DE

is

conv

erte

din

alg

ebra

iceq

uat

ion

an

d i

n

tran

sfer

fu

nct

ion

.

Page 55: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Bec

ause

of

n <

= m

, th

eref

ore

fro

mfo

rmu

lare

sult

sth

atth

ere

are

six

dif

fere

nt

typ

es

of

lin

ear

syst

ems.

Th

ese

wil

l b

e ca

lled

bas

ic t

ran

sfer

fu

nct

ion

s

·ga

ink

(pro

po

rtio

n)

·in

teg

ral

1/s

·fi

rst

ord

er

k/(

Ts+

1)

·d

iffe

ren

tia

ls

·se

con

d o

rde

r k

/(T

12

s2+

2ξT

2s+

1)

(da

mp

ed l

inea

r o

scil

lato

r)

·d

elay

exp(-

sTo)

()

()

()

()

Ys

Xs

kT

sT

sT

s

sT

sT

sT

s

ii

q

iib

idid

idid

j

iri

r

ipip

ipi

p

()

()=

±±

±

±±

±

==

=

==

∏∏

∏∏

11

22

1

1

22

1

12

1

12

1

ξ ξ

GEN

ER

ALIZ

AT

ION

Page 56: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Ba

sic

tra

nsfe

r fu

nctio

ns p

rop

ert

ies

will

com

e fro

m e

qua

tio

n

Exe

mp

lary

two

step

res

po

nse

sin

cyb

ern

etic

syst

em

Page 57: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Ga

in-

pro

pert

ies

()

()

yt

kut

=T

ime-

do

mai

neq

uat

ion

Tra

nsf

er f

unct

ion

Ste

p r

esp

on

se

Gs

k(

)=

()

1()

yt

ku

t=

time

k

0

1

Itis

stat

icfu

nct

ion

.

Fig

. S

tep r

esp

onse

Inp

ut

sig

nal

u(t

)

Ou

tput

sign

al y(t

)

Fig

. Sym

bo

l

Page 58: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Ga

in-

exam

ple

s

U1

U2

12

1

UU

iR−

=

2 2

Ui

R= R

RR

UU

2

12

12

+=

Cu

rren

tth

rou

gh

resi

stor

R1

R1

Cu

rren

t th

rou

gh

res

isto

rR

2R2

Ou

tput

volt

age

U2

Ele

ctri

cal

syst

em-

RR

circ

uit

Mec

han

ical

sy

stem

-lev

erF1

r 1r 2

F2

To

rqu

e F

1r 1

=F

2r 2

Ou

tput

forc

e F

2=

F1r 2

/r1

Mec

han

ical

syst

em-g

ears

12

12

TT

FR

R=

=F

orc

eb

etw

een

two

gea

rsis

equ

al

u(t)

y(t)

Rel

atio

nsh

ip b

etw

een f

orc

e, t

orq

ue

and

mo

men

tum

vec

tors

in a

ro

tati

ng s

yst

em

Page 59: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Inte

gra

l -

pro

pe

rtie

s

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Tim

e-d

om

ain

equ

atio

n

Tra

nsf

er f

unct

ion

Ste

pre

spo

nse

k

0

1

Itis

dy

nam

icp

roce

ss.

Fig

. S

tep

resp

onse

Fig

. Sym

bo

l

0

,(

)

td

yku

yk

ut

dt

dt=

=∫

()

yt

ku

t=

Gs

k s(

)=

time

Inp

ut

sig

nal

u(t

)

Ou

tput

sign

al y(t

)

Page 60: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Inte

gra

l -

exam

ple

s

Inp

ut

sig

nal

–vo

ltag

e

Ou

tput

sign

al–

shaf

tro

tati

on

angle

Ele

ctri

c sy

stem

AC

act

uat

or

N-z

ero

rob

ocz

e.

eL-

syg

nał

z r

egula

tora

(11

).

aL-

syg

nał

z r

egula

tora

(12

).

N-

zero

rob

ocz

e (N

).

L-

Syg

nał

(13).

Page 61: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Inte

gra

l -

exam

ple

s

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

u(t)

y(t)

PO

MP

A Ł

AD

UJĄ

CA

Z

AS

OB

NIK

PO

MP

A

CY

RK

UL

AC

YJN

A

Page 62: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Inte

gra

l -

exam

ple

s

u(t)

y(t)

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Fig

. R

ud

der

an

del

eva

tor

isco

ntr

oll

edby

Hyd

rau

lic

act

ua

tors

An

oth

erap

pli

cati

on:

bra

ke

intr

uck

Page 63: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Inte

gra

l -

exam

ple

s

u(t)

y(t)

Page 64: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Inte

gra

l -

exam

ple

s

Do

ub

leactu

ato

rin

Boe

ing

73

7

Page 65: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Page 66: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Page 67: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Page 68: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Fir

sto

rder

tran

sfe

r fu

nctio

n

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

k

0

1

Fig

. S

tep r

esp

onse

Fig

. Sym

bo

l

dy

Ty

kud

t+

=

Gs

k

Ts

()=

+1

()

1t T

yt

ku

e−

=∆

T

Ta

ng

ent

to a

cu

rve

Tim

e-d

om

ain

equ

atio

n

Tra

nsf

er f

unct

ion

Ste

pre

spo

nse

time

Inp

ut

sig

nal

u(t

)

Ou

tput

sign

al y(t

)

Page 69: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Lap

lace

tran

sfo

rm o

fD

C m

oto

r eq

uat

ion

s

ui a

Kt

Ra

La

ω

Eli

min

atin

g c

urr

ent

I aw

e ob

tain

()

2

()

()

t

aa

aa

tb

Ks

Us

LJs

JRB

Ls

BR

KK

Ω=

++

++

B(

)(

)(

)(

)(

)

()

-(

)0

aa

ab

ta

Ls

RI

sK

sU

s

Js

Bs

KI

s

+

=

= GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Fir

st o

rder

tran

sfe

r fu

nctio

n–

DC

moto

r

Page 70: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Ass

um

ing

smal

lin

du

ctan

ceL

a≈0

we

ob

tain

()

()

()

()

ta t

ba

KR

s

Us

JsB

KK

R

Ω=

++

Itis

pro

po

rtio

nal

acti

ng

elec

tric

co

mp

on

ent.

ω ωωω

atR

uK

Ba

bt

RK

K

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Fir

st o

rder

tran

sfe

r fu

nctio

n–

DC

moto

r

Page 71: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

ui a

Kt

Ra

La

ω

B(

)(

)(

)

()

1

ta t

ba

KR

sk

Us

JsB

KK

RT

s

Ω=

=+

++

Tra

nsf

er f

un

ctio

n,

La=

0:

00.1

0.2

0.3

0.4

0.5

02468

10

12

Tim

e (

secs)

Amplitude

ku

T

u

t

Ass

um

ing

, th

atk

=10

, T

=0

.1w

e

obta

inst

ep r

esp

on

se

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Fir

st o

rder

tran

sfe

r fu

nctio

n–

DC

moto

r

Page 72: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

V1

V2

V3

V=

abc

ρθ

ρθ

ρθ

ρθ

33

3

11

11

22

22

33

33

cV

d dt

cV

cV

cV

pp

pp

=+

−.

..

θθ

θθ

θθ

θθ

θ

110

1

220

21

330

3

=+

=+

=+

∆ ∆ ∆

01

11

12

22

23

33

3=

+−

ρθ

ρθ

ρθ

cV

cV

cV

pp

p

..

.

ρθ

ρθ

ρθ

ρθ

33

3

33

33

11

11

22

22

cV

d

dt

cV

cV

cV

pp

pp

∆∆

∆∆

+=

+.

..

[]

∆∆

∆θ

θθ

31

12

2

1

1(

)(

)(

)s

Ts

ks

ks

=+

+

TV V

kc

V

cV

kc

V

cV

p p

p p

==

=.

. .

. .

30

1

11

10

33

30

1

22

20

33

30

ρ ρ

ρ ρ

En

erg

y c

on

serv

atio

n e

qu

atio

n

Op

erat

ing

po

int

Sta

tic

char

acte

rist

ics

Dyn

amic

ch

arac

teri

stic

s

Lap

lace

tra

nsf

orm

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Fir

st o

rder

tran

sfe

r fu

nctio

n–

mix

ing

of

two

flu

ids

wit

hd

iffe

ren

t

tem

per

atu

res

k2

1/(

Ts+

1)

t3

++k1 t2t1

No

men

clat

ure

Page 73: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Fir

st o

rder

tran

sfe

r fu

nctio

n–

mix

ing

of

two

flu

ids

wit

h d

iffe

ren

t

con

cen

trati

on

s.

Ho

wch

ang

eso

utp

ut

con

centr

atio

nat

dif

fere

nt

dis

turb

ance

s?

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Ca

Ca

we

1/(

Ts+

1)

DIS

TU

RB

AN

CE

La

pla

ce

tra

nsfo

rm

L

ap

lace

tra

nsfo

rm

O

UT

PU

T

of

inp

ut

sig

na

l

of o

utp

ut

sig

na

l

Page 74: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Fir

st o

rder

tran

sfe

r fu

nctio

n–

pn

eum

ati

csy

stem

Page 75: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Fir

st o

rder

tran

sfe

r fu

nctio

n–

pn

eum

ati

csy

stem

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Page 76: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Fir

st o

rder

tran

sfe

r fu

nctio

n–

elec

tric

syst

em

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Fig

. R

C c

ircu

it

Page 77: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Fir

st o

rder

tran

sfe

r fu

nctio

n–

ther

ma

lsy

stem

, te

mp

eratu

re

sen

sor

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

α-w

spó

łczyn

nik

prz

ejm

ow

ania

cie

pła

,

υ-t

emp

erat

ura

,

τ-cz

as,

A-p

ole

po

wie

rzch

ni

czu

jnik

a,

m-m

asa

czu

jnik

a

T-s

tała

cza

sow

a,

c p–

ciep

ło w

łaśc

iwe

mat

eria

łu c

zu

jnik

a

Page 78: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Hig

he

r ord

er

tra

nsfe

r fu

nctio

ns

1

11

1...

nn

nn

nn

dy

dy

dy

TT

Ty

kudt

dt

dt

−−

++

++

=

()

()

1

()

1..

.1

n

kG

sT

sT

s=

++

11

0,

,...,

0n

nT

TT

−>

Iner

cja

3-g

o r

zęd

u

Iner

cja

2-g

o r

zęd

u

Iner

cja

1-g

o r

zęd

u

Ste

p r

esp

on

sein

1 s

,

Tim

e-d

om

ain

equ

atio

n

Tra

nsf

er f

unct

ion

Page 79: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Tra

nsfe

r fu

nctio

n o

f id

ea

l diffe

ren

tia

lsyste

m

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

∞ ∞∞∞

0

1

Fig

. S

tep

resp

onse

Fig

. S

ymb

ol

du

yT

kd

t=

Gs

Tks

()=

yt

Tk

t(

)(

)=

δ

Tim

e-d

om

ain

equ

atio

n

Tra

nsf

er f

unct

ion

Ste

pre

spo

nse

time

Inp

ut

sig

nal

u(t

)

Ou

tput

sign

al y(t

)

Page 80: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Tra

nsfe

rfu

nctio

n o

f re

al d

iffe

ren

tia

lsyste

m

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Fig

. S

tep

resp

onse

Fig

. S

ymb

ol

dy

du

Ty

Tk

dt

dt

+=

Gs

Tks

Ts

()=

+1

()

t Ty

tk

ue

−=

T0

k∆ ∆∆∆u ∆ ∆∆∆u

Tim

e-d

om

ain

equ

atio

n

Tra

nsf

er f

unct

ion

Ste

pre

spo

nse

timeIn

put

sig

nal

u(t

)

Ou

tput

sign

al y(t

)

Page 81: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Transferfunction of real

differentialsystem,e

xa

mp

le,

ele

ctr

ic s

yste

m

1)

(

)(

)(

12

+=

=T

sTs

sU

sU

sG

Page 82: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Transferfunction of real

differentialsystem,e

xa

mp

le,

me

ch

an

ica

lsyste

m

dy

du

Ty

Tk

dt

dt

+=

du

dy

cky

dt

dt

=+

Page 83: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Se

co

nd o

rder

tran

sfe

r fu

nctio

n

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

czas

Fig

. S

tep

resp

onse

Fig

. S

ymb

ol

22 2

12

12

02d

ydy

TT

yku

dt

dt

TT+

+=

<<

Gs

k

Ts

Ts

Gs

k

Ts

Ts

()

()

,

=+

+

=+

+

222

1

22

1

21

ξ

TT

T T=

=<

2

1 22

1,ξ

2

2

1(

)1

sin

11

t Tt

yt

ku

eT

ξ

ξϕ

ξ

=

∆−

−+

ϕ

ξξ

ξ=

<

arc

tg1

1

2

,

0

0.51

1.52

2.53

3.5

02

04

0

t

U,Y

Sko

k

Od

p

Tim

e-d

om

ain

equ

atio

n

Tra

nsf

er f

unct

ion

Ste

pre

spo

nse

time

Inp

ut

sig

nal

u(t

)

Ou

tput

sign

al y(t

)

Page 84: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Se

co

nd o

rder

tran

sfe

r fu

nctio

n -

exa

mp

les

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Page 85: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Se

co

nd

ord

er

tran

sfe

rfu

nctio

n-

exa

mp

les 1

di

uiR

Lid

tdt

C=

++

∫V

olt

ageu

dro

ps

con

secu

tiv

ely

on

resi

sto

r, i

nd

uct

or

and

con

den

ser

An

RL

Cci

rcu

it(a

lso

kn

ow

nas

are

son

ant

circ

uit

or

atu

ned

cir

cuit

)is

an

ele

ctri

cal

circ

uit

co

nsi

stin

g o

fa

resi

sto

r(R

),an

in

du

cto

r

(L),

and

aca

pac

ito

r(C

),co

nn

ecte

d i

n s

erie

s o

r in

par

alle

l.

Tu

ned

cir

cuit

sh

ave

man

y a

pp

lica

tio

ns

par

ticu

larl

yfo

ro

scil

lati

ng c

ircu

its

and

in

rad

ioan

d c

om

mu

nic

atio

n e

ngin

eeri

ng.

Th

ey c

an

be

use

dto

sele

cta

cert

ain

nar

row

ran

ge

of

freq

uen

cies

fro

m t

he

tota

l sp

ectr

um

of

amb

ien

tra

dio

wav

es.

Fo

rex

amp

le,

AM

/FM

rad

ios

wit

han

alo

gtu

ner

s ty

pic

ally

use

an

RL

Cci

rcu

itto

tun

ea

rad

iofr

equ

ency.

Mo

stco

mm

on

lya

var

iab

le c

apac

ito

r is

att

ach

ed

toth

e tu

nin

g k

no

b,

wh

ich

all

ow

s yo

u t

och

ang

e th

e v

alu

e o

fC

in t

he

circ

uit

an

d t

un

eto

stat

ion

so

nd

iffe

ren

t fr

equ

enci

es.

An

RL

Cci

rcu

it i

s ca

lled

ase

con

d-o

rder

circ

uit

asan

y v

olt

age

or

curr

ent

in t

he

circ

uit

can

be

des

crib

edb

y a

seco

nd

-ord

er

dif

fere

nti

al e

qu

atio

nfo

rci

rcu

it a

nal

ysi

s.

Page 86: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

De

lay

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

T0

0

1

Fig

. S

tep

resp

onse

Fig

. S

ymb

ol

0(

)y

ut

T=

Gs

eT

s(

)=

−0

0(

)1(

)y

tu

tT

=∆

Tim

e-d

om

ain

equ

atio

n

Tra

nsf

er f

unct

ion

Ste

pre

spo

nse

time

Inp

ut

sig

nal

u(t

)

Ou

tput

sign

al y(t

)

Page 87: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

De

lay -

exam

ple

s

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Fig

. G

rate

inw

ast

e u

tili

zati

on

faci

lity

Fu

el b

un

ker

Ste

am

bo

iler

Air

fan

un

der

the

gra

te

Co

mb

ust

ion

ch

am

ber

Co

al

con

veyo

r

Page 88: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Co

al

conve

yor

inp

ow

erst

ati

on

or

CH

P (

com

bin

ed h

eat

an

d p

ow

er)

or

cog

ener

ati

on

pla

nt

De

lay -

exam

ple

s

Page 89: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

De

lay –

exa

mp

les, scre

w c

on

ve

yo

r

Page 90: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

Plumber-artist

at work...

Page 91: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

GEN

ER

ALIZ

AT

ION

Basi

c t

ransf

er

functi

ons

pro

pert

ies

De

lay

–e

xa

mp

les, w

ate

r p

ipe

s

ch

imn

eyF

ire

pla

ce

rad

iato

rsu

pp

ly

retu

rnD

om

estic

cen

tra

l he

atin

gp

um

p

Sin

k

By-p

ass

Page 92: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

...

...

()

21

01

12

0

...

...

...

t

n

nk

uk

uk

uk

ud

yT

yT

yT

−+

++

++

=+

++

+∫

GEN

ER

ALIZ

AT

ION

Const

ants

meanin

gD

E o

flin

ea

rsyste

m

Pro

po

rtio

nal

P

Inte

gra

l

I

dif

fere

nti

atio

n

D

Co

ntr

ol

sign

alu

Ou

tpu

t si

gn

aly

Mu

st e

xis

t

Gai

n c

oef

fici

ents

Tim

e co

nst

ants

Page 93: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

...

...

()

()

21

01

2..

.1

...

mn

mn

ku

ku

ku

ku

yT

yT

yT

y+

++

=+

++

+

GEN

ER

ALIZ

AT

ION

Ste

ady–s

tate

gain

DE

of lin

ea

rsyste

m

Ifo

utp

utsig

na

lis

ste

ad

y, th

en

0k

uy

=

Co

effic

ient k

0

0

yk

u=

is c

alle

dsteady-state gain

.

Page 94: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

GEN

ER

ALIZ

AT

ION

Tra

nsf

er

functi

ons

pro

pert

ies

com

pari

son

Page 95: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

LIN

EA

RIZ

AT

ION

OF

NO

NLIN

EA

RSY

ST

EM

S

Page 96: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

LIN

EA

RIZ

AT

ION

OF N

ON

LIN

EA

R S

YST

EM

S

Intr

oducti

on

Ob

iekt

Fy

yy

xx

x(

,,

,,

,)

...

.

11

20

=

yd

y dt

yd

y

dt

xd

x dt

...

.

==

=2

2

Fy

xx

(,

,,

,,

)0

00

01

2=

∆∆

∆y

yy

xx

xx

xx

oo

o=

−=

−=

−1

12

2

∆∆

∆y

yx

xx

x.

..

..

.

==

=1

2

Fy

xx

F yy

F y

yF y

yF x

xF x

xF x

xR

(,

,,

,,

).

.

..

..

.

.

00

00

12

1

1

1

1

2

2+

+

+

+

+

+

+

=∂ ∂

∂ ∂

∂ ∂

∂ ∂∂ ∂

∂ ∂∆

∆∆

∆∆

∂ ∂∂ ∂

∂ ∂

∂ ∂∂ ∂

∂ ∂F y

yF y

yF y

yF x

xF x

xF x

x

+

+

+

+

+

=

∆∆

∆∆

∆∆

.

.

..

..

.

.

1

1

1

1

2

20

Ty

Ty

Ty

kx

kx

kx

01

21

12

13

2∆

∆∆

∆∆

∆+

+=

++

...

.

Let

’sta

ke

six

var

iable

eq

uat

ion

of

no

nli

nea

r sy

stem

Inp

ut

sig

nal

u1=

x1

Inp

ut

sig

nal

u2=

x2

Ou

tput

sign

aly

Tim

ed

eriv

ativ

esar

esi

gn

edb

y d

ots

Sta

tic

char

acte

rist

icis

des

crib

edb

y e

qu

atio

nw

ith

tim

ed

eriv

ativ

es

equ

alto

zer

o

Let

’sta

ke

smal

lch

ang

esar

ound

op

erat

ing

poin

t

Rec

all

Tay

lor

seri

es e

xp

ansi

on

Res

t

Tay

lor

seri

es a

llo

ws

to w

rite

equ

atio

n

In t

his

cas

e

Page 97: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Alg

ori

thm

of

lin

eari

zati

on

of

no

nli

nea

r sy

stem

1)

Wri

tedo

wn

all

var

iable

s an

dti

me

der

ivat

ives

2)

Co

mp

ute

equ

atio

n d

eriv

ates

for

all

var

iable

s

3)

Co

mp

ute

der

ivat

ives

val

ues

in

op

erat

ing

po

ints

4)

Wri

te d

ow

n l

inea

rize

d e

qu

atio

n

LIN

EA

RIZ

AT

ION

OF N

ON

LIN

EA

R S

YST

EM

S

Intr

oducti

on

...

.

12

1

,,

,,

,F

FF

FF

F

yx

xy

yx

∂∂

∂∂

∂∂

∂∂

∂∂

∂∂

∂ ∂∂ ∂

∂ ∂

∂ ∂∂ ∂

∂ ∂F y

yF y

yF y

yF x

xF x

xF x

x

+

+

+

+

+

=

∆∆

∆∆

∆∆

.

.

..

..

.

.

1

1

1

1

2

20

...

.

11

2,

,,

,,

yy

yx

xx

Page 98: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Fy

yy

yx

xx

xm

n(

,,

,...

,,

,,

,...

,)

...

()

...

()

11

0=

dF

=0

∂ ∂∂ ∂

∂ ∂∂ ∂

∂ ∂

∂ ∂F y

dy

F y

dy

F ydy

F xdx

F x

dx

F xdx

m

m

n

n

+

+

+

+

+

+

+

=

.

.

()

()

.

.

()

()

...

...

0

∂ ∂∂ ∂

F y

F xk

i(

)(

)

∂ ∂∂ ∂

∂ ∂∂ ∂

F yy

F yy

F xx

F xx

yy

m

yy

m

xx

n

xx

n

mm

nn

++

+

+

+

=

==

==

00

00

0∆

∆∆

∆..

...

.(

)

()

()

()

()

()

()

()

(1)

()

(1)

()

01

01

...

...

mn

mn

Ty

Ty

Ty

kx

kx

kx

∆+

∆+

+∆

=∆

+∆

++

LIN

EA

RIZ

AT

ION

OF N

ON

LIN

EA

R S

YST

EM

S

Genera

lizati

on

Let

’sta

ke

syst

em d

ecri

bed

by D

E

Tota

ld

eriv

ativ

eo

feq

uat

ion

Th

en

Par

tial

der

ivat

ives

in

op

erat

ing

po

int

Sub

stit

uti

ng

par

tial

der

ivat

ives

we

get

hyp

erpla

ne

Page 99: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

LIN

EA

RIZ

AT

ION

OF N

ON

LIN

EA

R S

YST

EM

S

Exam

ple

1

Lin

eari

zeeq

uati

on

ino

per

ati

ng

poin

t x

0=

1, y

0=

1 2.

34

yy

x

+

=

Solu

tio

n

1)

Var

iable

s.

,,

yy

x

2)

Der

ivat

ives

2.

34

.

.2

yy

x

y

y

+−

=

2.

34

23

yy

x

yy

+−

=

2.

34

34

yy

x

xx

+−

=

3)

Op

erat

ing

poin

t (d

eriv

ativ

es d

y/d

t=0!)

.

.

0

20

y

y=

=2

13

3y

y=

=3

14

4x

x=

=

4)

Lin

eari

zed

equ

atio

n

34

0y

x∆

−∆

=3(

1)4

(1)

0y

x−

−−

=

Page 100: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

LIN

EA

RIZ

AT

ION

OF N

ON

LIN

EA

R S

YST

EM

S

Exam

ple

1

-0.50

0.51

1.52

2.53

00

.51

1.5

22

.5

3(

1)4

(1)

0y

x−

−−

=

34

yx

= Op

erati

ng

poin

t

Sy

stem

sta

tic

cha

ract

eris

tic

Lin

eari

zed

eq

ua

tio

n o

f sy

stem

Page 101: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

LIN

EA

RIZ

AT

ION

OF N

ON

LIN

EA

R S

YST

EM

S

Page 102: 4 Control systems - Differential equationsfluid.itcmp.pwr.wroc.pl/~zaik/Dydaktyka/Basics of automatics/_4 Control... · DIFFERENTIAL EQUATIONS OF SYSTEMS DC Motor –principle of

Th

an

k y

ou fo

r

your

atten

tion