An Introduction to System Modeling and Control

Preface

Quite honestly, I never thought I would write a book for a first controls course. So, what happened? Well, in my teaching career I have taught out of the textbooks by Ogata [1], Kuo [2], Franklin et al. [3], and Phillips and Harbor [4] with lecture notes taken from Qiu and Zhou [5] and Goodwin et al. [6]. I did find many great ideas in these texts that I do use.¹ However, I was also disappointed that the modeling was not done using first principles of physics, but rather the model was simply stated without a derivation. To address this I made up my own lecture notes on rigid body dynamics (Chapter 05), DC motors (Chapter 06), and the inverted pendulum and magnetic levitation systems (Chapter 13). I realize that my emphasis on detailed modeling may be a “bug” to some (rather than a “feature”) as students find it difficult and it takes away from doing control “stuff”. However, as a colleague of mine put it, students develop important insight when they understand where the dynamic models come from and any linearization, approximation, or simplification used to obtain them.

It seemed to me early in my career that teaching the first controls course seemed to be more about its techniques, i.e., manipulating block diagrams, drawing root locus, Bode and Nyquist plots, doing the Routh–Hurwitz test, etc. Yet I think the course should be about making some physical system do what you want it to do such as having a robot arm rotate despite the weight of the object in its end effector, ...