Comparison of two design methods for PID controllers

Abstract

Analytical formulae for designing PI or PID controllers to give specified gain and phase margins have been proposed recently in the literature. The gain and phase margin (GPM) approach gives assurance of not only robustness but also level of performance. Another popular approach with similar emphasis is the internal model control (IMC) method. The two methods require only simple knowledge of the process thus avoiding comprehensive system identification. In this paper, a comparison of the two approaches (GPM and IMC) for designing a PI and a PID controller is made. The comparison shows the difference and the similarity of the two methods and when each method is most suitable to apply.