The mechatronic servo system is the major theme studied in this book. In particular, the servo system adopted in an electric servo motor is explained in this chapter. Several items of its utilization from the development stage to the present as well as its performances. The so-called mechanism machine (called as mechatronic servo system at the following), ., the servo system adopted in the numerical control machine or industrial robot, is generally different from the servo system introduced in the textbook of automatic control, which is very important when discussing the mechatronic servo system
