Model-free autotuning testing on a model of a three-tank cascade

Abstract

A newly developed model-free autotuning method based on frequency response analysis has been tested on a laboratory set-up that represents a physical model of a three-tank cascade. This laboratory model was chosen for the following reasons: a) the laboratory model was ready for computer control; b) simultaneously, computer simulation could be effectively utilized, because a mathematical description of the cascade based on quite exactly valid relations was available; c) the set-up provided the necessary degree of nonlinearity and changeable properties. The improvement of the laboratory set-up instrumentation presented here was necessary because the results obtained from the first experimental identification did not correspond to the results provided by the simulation. The data was evidently imprecise, because the available sensors and the conditions for process settling were inadequate.