Advanced control engineering (S.R. Burns, 2001)

$

$

$

$

#

Xo(S)

S

s + 1

$

$ #

#

$

R(s)

+

E(s)

E*(s)

C(s)

T

R(s)

+

E(s)

E *(s)

C(s)

C *(s)

–

T

T

$

#

r(t)

+

e(t)

e*(t)

Digital

u*(t)

Zero

u(t)

C(t)

–

Controller

Order

Plant

T

Hold

microprocessor

Sensor

$ $

$ ! "

jω

ωs

Im ω = ωs

2

4

(a)

(b)

(c)

(c)

(b)

ω =

ωs

(a)

r = 1

ω = 0

–σ

σ = 0

+σ σ

2

ω =

–ωs

Re

2

–ωs

ω = 4

–ωs

stable region

2

s-plane

z-plane