Dynamic Modeling and Control of Engineering Systems

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0521864356pre CUFX086/Kulakowski 0 521 86435 6 printer: Sheridan May 11, 2007 20:56
xii Preface
Chapters 11 and 12 introduce the important concept of a transfer function and
frequency-domain analysis. These two chapters are the most revised and (hopefully)
improved parts of the text. In previous editions of this text, we derived the complex
transfer function by using complex exponentials as input. For the third edition, we
retain this approach, but have added a section showing how to achieve the same
ends using the Laplace transform. It is hoped that this dual approach will enrich
student understanding of this material. In approaching these, and other, revisions,
we listened carefully to our colleagues throughout the world who helped us see where
the presentation could be improved. We are particularly grateful to Sean Brennan
(of Penn State) and Giorgio Rizzoni (of Ohio State) for their insightful comments.
This text, and the course that gave rise to it, is intended to be a prerequisite to
a semester-long course in control systems. However, Chapters 13 and 14 present a
very brief discussion of the fundamental concepts in feedback control, stability (and
algebraic and numerical stability techniques), closed-loop performance, and PID and
simple cascade controllers. Similarly, the preponderance of digitally implemented
control schemes necessitates a discussion of discrete-time control and the dynamic
effects inherent in sampling in the final chapters (15 and 16). It is hoped that these
four chapters will be useful both for students who are continuing their studies in
electives or graduate school and for those for which this is a terminal course of study.
Supplementary materials, including MATLAB and Simulink files for examples
throughout the text, are available through the Cambridge University Press web
back often as updates and additional case studies are made available.
Outcomes assessment, at the program and course level, has now become a fixture
of engineering programs. Although necessitated by accreditation criteria, many have
discovered that an educational approach based on clearly stated learning objectives
and well-designed assessment methods can lead to a better educational experience
for both the student and the instructor. In the third edition, we open each chapter
with the learning objectives that underlie each chapter. Also in this edition, the examples and end-of-chapter problems, many of which are based on real-world systems
encountered by the authors, were expanded.
This preface closes on a sad note. In March of 2006, just as the final touches were
being put on this edition, Bohdan Kulakowski was suddenly and tragically taken
from us while riding his bicycle home from the Penn State campus, as was his daily
habit. His family, friends, and the entire engineering community suffered a great loss,
but Bohdan’s legacy lives on in these pages, as does Lowen’s. As the steward of this
legacy, I find myself “standing on the shoulders of giants” and can take credit only
for its shortcomings. JFG
Boise, ID
May, 2007

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