Effect of dead time approximation on controller performance designed for a second order delayed model

The process models for many industrial processes can be represented by a Second Order Plus Dead Time system. In the present analysis, the selected Second Order plus Dead Time model is converted in to First Order plus Dead Time model using Taylor´s Series and Skogestad dead time approximation techniques. Controllers have been designed using Internal Model Control method, with various values of desirable closed loop time constants. A comparative study has been performed for closed loop responses for the original and the dead time approximated systems.