Feedback control is a pervasive, powerful, enabling technology that, at first sight, looks simple and straightforward, but is amazingly subtle and intricate in both theory and practice. In a dynamic system, changes cannot be
effected instantaneously, and so an otherwise correct control decision
applied at the wrong time could result in catastrophe. People’s lives may be at stake. There are no “details” in control engineering, as even the most insignificant “detail” may prove to be important. Real control systems must be extremely reliable, especially if people’s lives depend on them. Every engineer must be able to design and implement a computer control system.