Design and Implementation of Fractional Order Controllers Using Nelder-Mead Algorithm

The idea of fractional order controller in combination with Nelder Mead algorithm is proposed in this paper for controlling a multivariable industrial scale polymerization reactor. The concept of decentralization is also applied to identify the pairing and decentralization of loops for better performance of the controller. PID controller is tuned using Cohen-Coon (CC) tuning technique. CC tuning technique is more flexible and suitable in comparison to conventional Ziegler-Nichols tuning technique. Using Nelder-Mead optimization technique, the Fractional Order-PID (FO-PID) controller parameters including the special parametric values are calculated which plays a very important role in tuning of FO-PID controllers finely and for optimal performance of these controllers. Simulation results are obtained and dynamic characteristics and performance indices are calculated and analyzed.