%X The proportional-integral-derivative (PID) controllers have experienced series of structural modifications and improvements. Example of such modifications are set-point weighting and fractional ordering. While the former is to achieve two-degree-of-freedom (2DOF) ability of set-point tracking and disturbance rejection, the latter is to ensure smooth control action. Therefore, this paper reviews various forms of PID controllers and provides a comparative analysis of 2DOF PID and 2DOF fractional order PID (FOPID) controllers. The paper also discusses the conversion of one PID form to another. For the comparative analysis of the various controllers, a class of unstable systems are considered. Simulation result shows that in most cases the conversion from one form to another does not significantly affect the performance of the system. It is also observed that the 2DOF controllers (2DOF PID and 2DOF FOPID) improved significantly the performance of the ordinary PID controllers. © 2018 Polish Academy of Sciences. All Rights Reserved.
%K Controllers; Degrees of freedom (mechanics); Disturbance rejection; Electric control equipment; Three term control systems; Two term control systems, 2DOF PID; Fractional-order controllers; Fractional-order PID controllers; Proportional integral derivative controllers; Set point weighting; Structural modifications; Two-degree of freedom; Unstable system, Proportional control systems
%O cited By 26
%L scholars10675
%J Archives of Control Sciences
%D 2018
%N 4
%R 10.24425/acs.2018.125487
%T A comparative study of 2DOF PID and 2DOF fractional order PID controllers on a class of unstable systems
%V 28
%I Polish Academy of Sciences
%A K. Bingi
%A R. Ibrahim
%A M.N. Karsiti
%A S.M. Hassan
%A V.R. Harindran
%P 635-682