Comparison of several well-known controllers used in process control

In this paper, several well-known design methods, PID control, Smith predictor, inferential control, internal model control, Dahlin controller, deadbeat control, and predictive control, are studied. A suboptimal Smith predictor is derived. The relationship among these methods is investigated. It is shown that these methods are equivalent to each other on certain premises. This explains why they are widely used in process control and provides insight into the work of bringing these techniques together to control system design. Examples are given to illustrate the result.