Chapter 17 PID Control Without Math
Note: This chapter is a corrected reprint of the article “The darker side: PID control without math,” Circuit Cellar, no. 221, December 2008.
The vast majority of real-world systems are based on feedback loops. Broadly speaking, a feedback loop is used to manipulate the inputs to a system to obtain a desired effect on its outputs in a controlled way. Your DVD player uses a feedback loop to drive its spinning motor at a precise rotation speed. Your mobile phone has a feedback loop to adjust its transmission power to the required level. And, of course, your car has plenty of feedback loops (not only in the cruise control module).
The vast majority of real-world systems are based on feedback loops. Broadly speaking, ...