preface
In
this
Seventh
Edition
we
again present a text in support
of
a first
course
in
control
and
have
retained the best features
of
our
earlier editions.
For
this
edition,
we
have
responded
to
a survey
of
users by adding
some
material
(for
example,
gears
in
Chapter
2) and moved other little-used material from
the
printed
book
(for
example,
digital control in the early chapters)
to
a
website
that
is
fully
accessible
to readers.
We
have also updated the text
throughout
so
that
it
uses
the
improved
features
of
Matlab®. But perhaps the
biggest
jolt
to
our
readers
is that
we
succumbed to the times, and changed the
notation
used
for
the
state-space
description from
(F,
G,
H,
J) to (A, B, C,
0)!
In
past
editions,
our
loyalty
to
the early pioneers in the state-space
approach
overwhelmed
our
ability
to
accept reality, and we stayed with the
classical
notation.
However,
for this edition, we decided the time
ha~
come
to
accept
the
reality
that
the
dominant
notation in the field today is (A, B,
C,
0)
as
is
the
notation
in Matlab. We have also added a section
on
feedfoward
control
to
Chapter
4
and
a model-following section to Chapter 7. In addition,
the
presentation
of
PIO
control has been improved as has some
of
the
Laplace
transform
material. We strive to equip control system designers
with
the
theory,
basic
design
methods. and an introduction to computer-aided
design
methods.
At
the
same
time. we also strive to equip designers with a
basic
understanding
so
that computer results can be guided and verified.
The
case
studies
in
Chapter
10
have been retained and updated where needed. Finally,
in
order
to
guide
the reader in finding specific topics. both in the text
and
on
our
website,
we
have expanded the table
of
contents to include
entries
for
material
that
is
on
the website as well as in the printed book.
The
basic
structure
of
the book
is
unchanged and we continue to
combine
analysis
with
design
using the three approaches
of
the root locus,
frequency
response,
and
state-variable equations. The text continues
to
include
many
carefully
worked
out exan1ples to illustrate the material.
As
before,
we
pro-
vide
a
set
of
review questions at the
end
of
each chapter with
answers
in
the
back
of
the
book
to assist the students in verifying that they have
learned
the
material.
In
the
three central chapters
on
design methods we continue
to
expect
the
students
to
learn how to perform the very basic calculations by
hand
and
make
a rough sketch
of
a root locus
or
Bode plot as a sanity
check
on
the
computer
results and as an aid to design. However,
we
introduce
the
use
of
Matlab
early
on
in recognition
of
the universal use
of
software
tools
in
control
analysis and design. Furthermore. in recognition
of
the fact
that
very
few instructors were using the early material
on
Digital
Control
in
Chapters
4,
5, and 6 in the sixth edition, that material was moved to
our
website
and
Chapter
8 was modified
so
that it
prov~"'··
introduction
to Digital Control. For those
~rs
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of
controllers
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