Design of Optimally Tuned Two Degree of Freedom Fractional Order PID Controller for Magnetic Levitation Plant

Proper tuning along with design of Fractional Order PID (FOPID) controllers is a problem that has received immense attention and has been studied extensively since last few decades. The FOPID controller has been proved superior to the Integer Order PID (IOPID) controller in several aspects which has led to its application in various nonlinear systems. This work demonstrates the design of a 2-Degree of Freedom (DOF) FOPID controller for a magnetic levitation (maglev) plant, which is a nonlinear and unstable system. The controller parameters are tuned using Symbiotic Organisms Search (SOS), which is a recent and efficient evolutionary algorithm, to achieve better system performance, in both time and frequency domain. To determine the efficacy of the controller, it's performance is compared with 1-DOF FOPID controller.