Enhanced Control with a General Cascade Control Structure

In this paper, a general cascade control structure is proposed to handle stable, integrating, and unstable processes for cascade control systems. With the structure, a IMC controller is derived to get a desired closed-loop response and converted to a conventional PID controller. Several examples are given to illustrate the superiority of the structure and the proposed controller. The new structure is more robust to measurement noises than a conventional cascade control structure.