Effect of delay approximation using Pade technique on controller performance designed for a SOPDT model

Abstract

Second order plus dead time model approximates many processes in the chemical, metallurgical, paint, paper, oil refineries and petroleum industries. PID controller is commonly used to control an industrial process. In the present analysis, various PID controllers based on Skogestad and Internal Model Control principles with different closed loop constants have been designed for a selected Second Order plus Dead Time model. The selected model is approximated using different approximation techniques. Significant time response characteristics of closed loop responses for the designed controllers are compared and analyzed for set-point tracking of the controller.