Abstract
In this study, a fractional and cascaded controller type FOPI-FOPD is designed to control the DC motor speed. The proposed controller parameters are tuned via Sparrow Search Algorithm (SSA) which is a recently introduced metaheuristic optimization algorithm. Various types of objective functions are employed to search the proposed controller parameters. These objective functions are the integral of time multiply absolute error (ITAE), the integral of absolute error (IAE),the integral of time multiply squared error (ITSE), the integral of squared error (ISE), and Zwe-Lee Gaing (ZLG). The results obtained from the objective functions were compared in the time domain in terms of overshoot (M_p), settling time (t_s), and ramp time (t_r). In addition, the obtained results are examined in terms of gain margin, phase margin, and bandwidth in the frequency domain. The best results obtained from different objective functions in the time and frequency domain were compared with the studies in the literature. In addition, for the best result obtained in the proposed controller, robustness, disturbance load, and reference speed change analysis were examined.