Disturbance rejection performance analyses of closed loop control systems by reference to disturbance ratio

Baris Baykant Alagoz; Furkan Nur Deniz; Cemal Keles; Nusret Tan

doi:10.1016/j.isatra.2014.09.013

Disturbance rejection performance analyses of closed loop control systems by reference to disturbance ratio

ISA Trans. 2015 Mar:55:63-71. doi: 10.1016/j.isatra.2014.09.013. Epub 2014 Oct 11.

Authors

Baris Baykant Alagoz¹, Furkan Nur Deniz², Cemal Keles³, Nusret Tan⁴

Affiliations

¹ Inonu University, Electrical-Electronics Engineering, Turkey. Electronic address: baykant.alagoz@inonu.edu.tr.
² Inonu University, Electrical-Electronics Engineering, Turkey. Electronic address: furkan.deniz@inonu.edu.tr.
³ Inonu University, Electrical-Electronics Engineering, Turkey. Electronic address: cemal.keles@gmail.com.
⁴ Inonu University, Electrical-Electronics Engineering, Turkey. Electronic address: nusret.tan@inonu.edu.tr.

PMID: 25311160
DOI: 10.1016/j.isatra.2014.09.013

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.

Keywords: Disturbance rejection control; Disturbance suppression; Fractional order PID controllers; PID controllers; Reference to disturbance ratio (RDR).