mechanical

I am a practicing systems engineer in industry. My company, Transpower Corporation, writes custom and commercial engineering and accounting software. Over the years I've purchased many, many control engineering books, including the fourth and seventh editions of Prof. Dorf's Modern Control Systems. At my request, Dr. Dorf sent me the solutions manual. Unlike the other reviewers here, I find the book to be easy reading, particularly because of the many fine illustrations which add immensely to the clarity of presentation. The 800 problems contained in the book cover a very wide range of modern real-life control systems; they are vastly better than the problems contained in any other control book I've purchased.

The book is very strong on classical methods, but rather weak on the so-called "modern methods." I happen to prefer the Internal Model Principle and even wrote a software package, Optimal Control Designer, to make that method easy to apply. Unfortunately Dorf treats the Internal Model Principle only briefly. The same goes for LQR and other optimization methods. On the other hand, ITAE and deadbeat systems are treated rather well.

The use of MATLAB in the book and problems is very welcome. However, Simulink is not used. Those of us in industry are likely to use Simulink to simulate a proposed system to death before production. Hopefully the forthcoming 10th edition will include example applications using Simulink.

One other deficiency is the lack of treatment of real-time computer control (for example using Real-Time Workshop and Real-Time Windows Target). I haven't yet found any text on control which goes into any detail on this subject--those of us in industry would very much like such a text.

In summary I highly recommend this book. It's worth the price just for the spectacular set of end-of-chapter problems.

If you want to learn about Modern Control Systems the first time around then use a book written by Ogata, Kuo or Nise. These three authors have some of the best books on this subject that you will ever see.

As for this book
GOOD:
The Matlab part of the book I would give 4 stars. It is pretty good and lets you get acquainted with the control toolbox. There are a wide variety of problems in the book and it has a lot of design problems for the reader. Problems include exercise problems, regular problems (beats me why he didn't put them together), advance problems and Matlab Problems. If you already know the subject then it could possibly be a good design book.

BAD:
Worst book I have ever read. This book offers some of the worst explanations I have ever seen in a book. It is nearly impossible to do the problems with the information given to you. Reading the book is like solving an exercise problem in itself. A lot of times the math is skipped so you have no idea how he got to the answer. While other books happened to spend 4 pages on a topic, Dorf managed to compress it into a useless paragraph. Also, Dorf expects you to clairvoyantly know what a definition is. When reading through a chapter he talks about something without telling you what it is. Somehow he expected you to know that at the end of the chapter, AFTER you've read everything he'll give you a definition list. Very few exercise problems have answers to them so if you are doing something wrong then you will not know. If you are looking for self-study from this book then start crying now because you will throw over 100 bucks in the garbage.

The most definitively annoying thing about the book is how it references other books. Dorf commonly gives you a sentence on a topic and then references the sentence to another book. Those sentences are meaningless and explain nothing, which gave me the impression that I was supposed to go to one of the hundreds of referenced books to learn what he was talking about.

IN SUM:
The only people who will like this book are the ones who already know the subject. I found that after I read Modern Control Engineering by Ogata and understood the subject, I appreciated a FEW of the examples Dorf gave, even though I could find a slew of books that could cover that material better. If you are a teacher looking to make this your class's book, reconsider because your students will not learn the subject.

Not once in all my university courses have I had a text that is this frustrating. It presents results without justification, it uses examples with no explanation, it weighs a ton and yet refers you to their website on every other page because the necessary material isn't even included in the book. If you have a university/college course that requires this text PLEASE do your whole campus a favor and tell the prof. to change to something else.