Tuning of an iP controller for a time-delayed plant by a performance portrait method

Abstract

This paper deals with a performance analysis and optimal tuning of an intelligent proportional (iP) controller for the first order time delayed plants. iP control represents the simplest solution used within the so called “model free control”. Although it has been primarily developed for more complex nonlinear plants, its basic performance analysis may preferably be carried out in a simple linear setup by considering an integral time delayed plant with an input (load) disturbance. The corresponding disturbance observer is based on a finite-impulse-response (FIR) filter, which makes an analytical tuning inapplicable. The paper shows, how it may be carried out by the performance portrait method. Inspired by analogous problems solved already in a traditional disturbance observer based control, comparison of both approaches shows new interesting features of the “model free” control under time delays.