Comparing filtered PI, PID and PIDD control for the FOTD plants

Abstract

The aims of the paper are: (a) to extend the 2DOF PI and PID controller design for the first order time-delayed (FOTD) plant by the multiple real dominant pole method to the 2DOF PIDD2 control, (b) to modify for this controller augmented by an nth order series binomial filter required for the derivative action implementation and measurement noise attenuation the simple integrated tuning procedures known already for the PI and PID control. (c) to align all the filtered controllers as for the guaranteed stability range in case of unstable plants, and (d) to compare the performance limits expressed in terms of the integral of absolute error (IAE) and (e) to discuss the corresponding closed loop robustness by a simple test based on comparing impacts of “exact” and simplified tunings based on the integral + dead time (IPDT) models.