title: Disturbance rejection performance analyses of closed loop control systems by reference to disturbance ratio.
abstract: This study investigates disturbance rejection capacity of closed loop control systems by means of reference to disturbance ratio (RDR). The RDR analysis calculates the ratio of reference signal energy to disturbance signal energy at the system output and provides a quantitative evaluation of disturbance rejection performance of control systems on the bases of communication channel limitations. Essentially, RDR provides a straightforward analytical method for the comparison and improvement of implicit disturbance rejection capacity of closed loop control systems. Theoretical analyses demonstrate us that RDR of the negative feedback closed loop control systems are determined by energy spectral density of controller transfer function. In this manner, authors derived design criteria for specifications of disturbance rejection performances of PID and fractional order PID (FOPID) controller structures. RDR spectra are calculated for investigation of frequency dependence of disturbance rejection capacity and spectral RDR analyses are carried out for PID and FOPID controllers. For the validation of theoretical results, simulation examples are presented.
authors.affiliation: Inonu University, Electrical-Electronics Engineering, Turkey. Electronic address: baykant.alagoz@inonu.edu.tr.
authors.forename: Baris Baykant
authors.initials: BB
authors.lastname: Alagoz
authors.affiliation: Inonu University, Electrical-Electronics Engineering, Turkey. Electronic address: furkan.deniz@inonu.edu.tr.
authors.forename: Furkan Nur
authors.initials: FN
authors.lastname: Deniz
authors.affiliation: Inonu University, Electrical-Electronics Engineering, Turkey. Electronic address: cemal.keles@gmail.com.
authors.forename: Cemal
authors.initials: C
authors.lastname: Keles
authors.affiliation: Inonu University, Electrical-Electronics Engineering, Turkey. Electronic address: nusret.tan@inonu.edu.tr.
authors.forename: Nusret
authors.initials: N
authors.lastname: Tan
keywords: Disturbance rejection control; Disturbance suppression; Fractional order PID controllers; PID controllers; Reference to disturbance ratio (RDR)