Cascade PID Control Systems

Abstract

Cascade proportional integral derivative (PID) control systems are very important for successful applications. Most physical systems are complex in dynamics and cascade PID control systems offer effective solutions to their control problems, where a complex system is decomposed into several smaller and simpler systems for which PID control systems are designed for each of them. Understanding how the neglected dynamics affect the closed‐loop performance of the cascade control system is important for the design and applications. The chapter examines the variations of the closed‐loop poles of the cascade control system. One of the major advantages in using cascade control lies in its characteristics with regard to disturbance rejection. The chapter also examines the properties of input disturbance rejection in cascade control with both frequency response analysis and simulation studies. The input disturbance occurred at the inner‐loop system is much more effectively compensated in the cascade control structure.