Stability testing and IMC based fractional order PID controller design for heating furnace system

Industrial heating furnaces have many special characteristics like huge capacity, long lag, non-linear attribute etc. Due to these properties, it is very essential to design an appropriate controller for these furnace systems so that proper operation as well as safety of the workers around it is ensured. This implies that, the stability analysis and controller design for these heating furnace systems is an important and at the same time very challenging task. Therefore, in this paper the stability analysis of the fractional order model of the heating furnace system is carried out using Matignon theorem. Further, Internal Model Control (IMC) based fractional order PID controller is designed for the fractional model of the heating furnace in order to achieve suitable performance indices. The proposed controller design for fractional heating furnace system gives better performance in comparison to its integer order model. Finally, the robustness of the designed controller is shown for ±50% parameter uncertainty and the performance analysis is done using the integral error criterion.